Projects Available

This page gives details of all projects currently on offer for research towards a DPhil in Materials Science at the Department of Materials, University of Oxford.

The website lists available projects in two categories, 'Funded Projects (subject to contract)' and 'Other Projects'. Some projects listed in the 'Other Projects' section may be suitable also for an MSc(Research) in Materials, and those offered by staff who are members of one or more of Oxford's EPSRC CDT's may be suitable for a CDT programme DPhil project. In all these cases please contact the supervisor(s) for clarification.

Open Admissions cycle deadline:  31 July 2016


Important information for applicants

Important information for applicants

 

SELECTION OF PROJECTS

When completing the Oxford application form, under the 'Supporting Materials' section entitled 'statement of purpose/personal statement', you must list in order of preference up to five preferred research topics/supervisors selected from those advertised on this website. In addition you should include a short statement (up to 400 words) to outline your research interests and indicate the rationale behind your choice of projects. We do not require a research proposal.

If you wish to learn more about a specific project you may e-mail the relevant supervisor.

The website describes available projects in two categories, 'funded projects (subject to contract)' and 'other projects'. Generally the projects do not have specific deadlines, as we intend to consider applicants within the University of Oxford's Graduate Admissions standard application fields. Some of the descriptions on this website are of projects that carry earmarked funding and in these cases the eligibility of home, EU and overseas applicants is indicated. These classifications as ‘Home/EU’ or ‘Overseas’ are set by the University.

Normally overseas students will require a visa and, for Materials Science, an ATAS certificate (http://www.ox.ac.uk/students/visa). More information is given below in our guide for overseas applicants.

CLOSING DATES

Until the middle of March applications will be considered in three fields, as advertised in the Oxford University Graduate Studies Prospectus. Deadlines for the receipt of fully completed applications and references are 12.00 noon (UK time) on: 20 November 2015, 22 January 2016 and 11 March 2016. Applications received after 11 March will be considered on an individual basis and may be submitted at at any time. Overseas or scholarship applicants are strongly advised to apply in the November field and home/EU applicants in the January field. In addition, project studentships with specific closing dates may be advertised on our website.

Details of how to apply are found at http://www.ox.ac.uk/admissions/graduate/applying-to-oxford/application-guide.

Before submitting an application you are strongly encouraged to contact the Department of Materials' Graduate Studies Secretary (graduate.studies@materials.ox.ac.uk) for advice and assistance.

FUNDING and PLACES

Please note that funding and places may be exhausted after the first two application cycles: applications received after 22 January 2016 will be considered only if places and/or funded projects remain unfilled. We expect to make a small number of offers, to outstanding candidates, following evaluation of the November applications. The remaining good candidates from November will be considered automatically in January, along with the new applicants for that deadline, and we normally expect to offer the majority of available places following evaluation of the January applications.

The Department of Materials strongly advises applicants for scholarships to apply in the first application field (application deadline 12 noon UK time on 20 November 2015), although those who apply in the second field (application deadline 12 noon UK time on 22 January 2016), will also be considered.

One or two EPSRC DTP studentships may be offered to world-class applicants (those of similar quality to successful Clarendon Scholarship applicants) following evaluation of the November applications, but we normally expect to award the majority following evaluation of the January applications. Prior to final ranking, interviews will be held for all short-listed applicants from the November and January gathered fields who are eligible for DTP awards. We do not assign Departmental DTP studentships to specific projects unless this is advertised in advance on our website. Overall there are many more projects advertised in the 'other project' category than the number of DTP studentships we have available. Hence, in a given year, some of the 'other projects' may be designated as ineligible for DTP funding. These projects are marked with the symbol §. Normally the most able and suitable applicants, as judged against our Graduate Admissions Criteria, are offered the awards; normally subject to a limitation of no more than one DTP studentship per supervisor per year.

UK applications
EU applications
Overseas applications

Further details may be obtained from the secretary to the Director of Graduate Studies:
Mrs Marion Beckett: tel: 01865 (2)83226; fax: 01865 273789; email:graduate.studies@materials.ox.ac.uk


Funded projects - important information

FUNDED PROJECTS - Important information

Projects in this section carry their own funding (subject to contract with the sponsor), so finance in the form of a stipend and payment of fees is available to the successful candidate. However, eligibility for funding is in some cases restricted by the applicant's country of legal residence: below and in the detailed description of funded projects we use the term 'citizen' in respect of this country.

For projects marked *: full funding is available only to UK citizens, although EU citizens are eligible to have their fees paid if they can provide their living costs from another source.

For projects marked **: applicants should in general be citizens of either a member state of the European Union or an Associated State (except the United Kingdom) or have resided in the European Union for several years. UK citizens are eligible only if they have been resident outside the EU Member or Associated States for several years. Precise details of eligibility vary from project to project; more information is included as part of the detailed project description.

For projects marked ***: the funding is available to all applicants, but the fees are covered only at the home/EU rate. Therefore, overseas students would have to provide the difference between home/EU and overseas student fees from some other source such as a scholarship or personal funds. For students who commence their studies in October 2015 this difference is expected to be in the region of £44,000 over three years. Please see http://www.ox.ac.uk/admissions/graduate/fees-and-funding for a statement of the actual fees.

4 funded projects available at present.

***“Experimental validation of Inter-granular stress corrosion cracking (IGSCC) predictive models”
( Supervisors: Prof Sergio Lozano-Perez , Prof James Marrow (Oxford), Dr Fabio Scenini (Manchester))

*Defect engineering in diamond for magnetic field imaging and gradiometry
( Prof Jason Smith and Prof Martin Booth, Dept of Engineering Science)

*Spectroscopy and modelling of catalyst nanoparticles
( Dr R J Nicholls, Dr D Ozkaya^, Dr M Schuster^, Prof P D Nellist (^Johnson Matthey))

PhD Studentship in Materials Chemistry, Electrochemistry and Energy Storage
( Professor P G Bruce / Professor M Pasta)

New projects are added from time-to-time, so please review the list regularly.


Supervisors who are members of an EPSRC CDT

SUPERVISORS WHO ARE MEMBERS OF AN EPSRC CDT

Projects offered by staff who are members of one or more of Oxford's EPSRC CDT's may be suitable for a CDT programme DPhil project. In all these cases please contact the supervisor(s) for clarification.

Science & Technology of Fusion EPSRC CDT

Prof S.G. Roberts, Dr D.E.J. Armstrong, Dr P. Bagot, Prof P.S. Grant, Prof S.L. Lozano-Perez, Prof T.J. Marrow, Prof M. Moody, Prof A.J. Wilkinson

Diamond Science & Technology EPSRC CDT

Prof J.M. Smith, Prof R.I. Todd,

New & Sustainable Photovoltaics EPSRC CDT

Prof H.E. Assender, Prof F. Giustino, Prof A.A.R. Watt

Science & Applications of Plastic Electronics EPSRC CDT

Prof H.E. Assender, Prof A.A.R. Watt

Theory & Modelling in Chemical Sciences EPSRC CDT

Prof F. Giustino, Dr J.R. Yates

Biomedical Imaging MRC & EPSRC CDT

Prof C.R.M. Grovenor

Projects - listed by supervisor in alphabetical order

PROJECTS - listed by supervisor, in alphabetical order

  •  

Dr David Armstrong (david.armstrong@materials.ox.ac.uk)

Professor Hazel Assender (hazel.assender@materials.ox.ac.uk)

Dr Paul Bagot (paul.bagot@materials.ox.ac.uk)

Professor Simon Benjamin (simon.benjamin@materials.ox.ac.uk)

Professor Harish Bhaskaran (harish.bhaskaran@materials.ox.ac.uk)

Professor Andrew Briggs (andrew.briggs@materials.ox.ac.uk)

Professor Peter G Bruce FRS (peter.bruce@materials.ox.ac.uk)

Professor Martin Castell (martin.castell@materials.ox.ac.uk)

Professor Jan Czernuszka (jan.czernuszka@materials.ox.ac.uk)

Dr Steve Fitzgerald (steven.fitzgerald@pmb.ox.ac.uk)

Professor Marina Galano (marina.galano@materials.ox.ac.uk)

Professor Feliciano Giustino (feliciano.giustino@wolfson.ox.ac.uk)

Professor Patrick Grant FIMMM FREng (patrick.grant@materials.ox.ac.uk)

Professor Nicole Grobert (nicole.grobert@materials.ox.ac.uk)

Professor Chris Grovenor, FIMMM, FIP (chris.grovenor@materials.ox.ac.uk)

Professor Angus Kirkland (angus.kirkland@materials.ox.ac.uk)

Dr Edward Laird (edward.laird@materials.ox.ac.uk)

Professor Sergio Lozano-Perez (sergio.lozano-perez@materials.ox.ac.uk)

Professor James Marrow (james.marrow@materials.ox.ac.uk)

Dr Jan Mol (jan.mol@materials.ox.ac.uk)

Professor Michael Moody (michael.moody@materials.ox.ac.uk)

Professor Peter Nellist (peter.nellist@materials.ox.ac.uk)

Dr Rebecca Nicholls (rebecca.nicholls@materials.ox.ac.uk)

Professor Keyna O'Reilly (keyna.oreilly@materials.ox.ac.uk)

Prof Mauro Pasta (mauro.pasta@materials.ox.ac.uk)

Professor Kyriakos Porfyrakis (kyriakos.porfyrakis@materials.ox.ac.uk)

Professor Steve Roberts FIMMM, FInstP. (steve.roberts@materials.ox.ac.uk)

Professor Jason Smith (jason.smith@materials.ox.ac.uk)

Professor Susie Speller (susannah.speller@materials.ox.ac.uk)

Dr Edmund Tarleton CEng, MIMMM (edmund.tarleton@materials.ox.ac.uk)

Professor Richard Todd (richard.todd@materials.ox.ac.uk)

Dr Aurelien Trichet (aurelien.trichet@materials.ox.ac.uk)

Professor Jamie Warner (jamie.warner@materials.ox.ac.uk)

Professor Andrew Watt (andrew.watt@materials.ox.ac.uk)

Professor Angus Wilkinson (angus.wilkinson@materials.ox.ac.uk)

Professor Peter R Wilshaw (peter.wilshaw@materials.ox.ac.uk)

Professor Jonathan Yates (jonathan.yates@materials.ox.ac.uk)

(return to top of list of other project titles listed by supervisor)

Projects - listed by primary research area

PROJECTS - listed by primary research area

 

Centre for Applied Superconductivity

The Materials Department will open a new £6M Centre for Applied Superconductivity in 2015; a collaboration with the Clarendon Laboratory and a team of industrial partners. This centre will specialise initially in the measurement of superconducting properties and in materials discovery across the whole range of practical applications for superconducting materials. We have openings for graduate students to join this new centre, all of whom will have the opportunity to work on industry-related projects at the interface between materials, physics and engineering.

Characterisation of Materials

Computational Materials Modelling

Device Materials (including semiconductors)

Energy Materials (including batteries)

Nanomaterials

Polymers and Biomaterials

Processing and Manufacturing

Quantum Information Processing

Structural and Nuclear Materials

(return to list of other project titles listed by research area)


 

FUNDED PROJECTS - full details, listed by title

Eligibility for some projects is restricted and these are marked with asterisks. For further details of these restrictions, please see the introductory section on funded projects earlier in these web pages on 'New DPhil Projects Available'.

***“Experimental validation of Inter-granular stress corrosion cracking (IGSCC) predictive models”
Supervisors: Prof Sergio Lozano-Perez , Prof James Marrow (Oxford), Dr Fabio Scenini (Manchester)

Stress Corrosion Cracking (SCC) is a very important mode of failure in nuclear reactors.  A lot of effort from the scientific community has been dedicated to develop more accurate predictive models for crack initiation and propagation.  EDF has produced one of the most comprehensive models to date and this project aims to validate it through direct characterization.  We aim to produce a fully comprehensive benchmark dataset that allows a better validation and optimization of IGSCC models.  For this purpose, we will test a nickel alloy in simulated reactor conditions (autoclave) and fully characterize the resultant stress corrosion cracks.

The student will be based in Oxford and work in close collaboration with EDF and the University of Manchester.  Frequent trips to both institutions are expected.  He/she will be in charge of sample design and preparation for autoclave testing in Manchester and characterization including EBSD, FIB, 3D tomography, DIC and TEM in Oxford and Manchester.

Candidates are expected to hold a first class or strong upper second class degree (or equivalent international qualifications), as a minimum, in Chemistry, Materials Science, Physics, Engineering or a related science subject.  A Master’s degree in a related discipline is also desirable.

Candidates are recommended to apply as soon as possible as applications will be considered on an individual basis as and when they are received and this position will be filled as soon as possible, but the latest date for considering applications will be 31 July 2016.

Subject to contract this project will be supported by a 3.5 year studentship sponsored by the Materials Ageing Institute (MAI) and EDF.  This studentship will provide full fees and maintenance for a student classified as home fee status (this includes an EU student who has spent the immediate previous three years, or more, in the UK undertaking undergraduate study) or EU fee status.  Further information on the availability of funding can be obtained from Marion Beckett, graduate.studies@materials.ox.ac.uk.  The stipend will be at least £17,296 per year.

Students classified as overseas fee status are eligible for this funded project, but would have to provide the difference between home/EU and overseas student fees from some other source such as a scholarship or personal funds. For students who commence their studies in October 2016 this difference is expected to be in the region of £46,000 over three years.  Please see http://www.ox.ac.uk/admissions/graduate/fees-and-funding for a statement of the actual fees.

Any questions concerning the project can be addressed to Professor Sergio Lozano-Perez (sergio.lozano-perez@materials.ox.ac.uk).  You can also visit his group website: http://www.ox.ac.uk/admissions/postgraduate_courses/apply/index.html

Also see homepages: Sergio Lozano-Perez James Marrow

*Defect engineering in diamond for magnetic field imaging and gradiometry
Prof Jason Smith and Prof Martin Booth, Dept of Engineering Science

Nitrogen-vacancy (NV) defects in diamond have generated enormous interest in recent years for their highly coherent spin properties and convenient optical interface. Magnetometry using the electron spin in an ensemble of NV- defect has been shown to be capable of detecting fields of <1 pT Hz-1/2 such that their use as quantum field sensors is generating significant industrial interest. Companies known to be building commercial magnetometry systems with NV centres include Bosch (navigation systems), and several organisations are developing NV-based magnetic imaging systems with ~10nm resolution for biological and physical sciences.

In the past two years we have demonstrated that laser processing with aberration correction can produce high quality single NV centres at precise locations in bulk diamond materials. This PhD project will use the technique we have developed (patent applied for) to produce regular 2D and 3D arrays of NV centres in diamond, and use these arrays to demonstrate magnetic field imaging and gradiometry.

The student will carry out laser processing in the Booth group, and characterisation using photoluminescence spectroscopy and optically detected magnetic resonance in the Smith group. He/she will measure the electron spin coherence times of the NV centres to assess their suitability for magnetometry. The best samples will be used to demonstrate magnetic field imaging and gradiometry. The project will take place within the UK Quantum Technologies programme, with the goal to produce commercial technologies from quantum science. Oxford hosts the UK Hub in Networked Quantum Information Technologies, providing an exciting and dynamic environment in which to carry out the project.

Applications will be considered as and when they are received and this position will be filled as soon as possible, but the latest date for considering applications will be 29 July 2016.

This 3-year studentship will provide full fees and maintenance for a student as home fee status (this includes an EU student who has spent the previous three years (or more) in the UK undertaking undergraduate study). The stipend will be £14,296 per year. Other EU students should read the guidance at http://www.materials.ox.ac.uk/admissions/postgraduate/eu.html for further information about eligibility.

Any questions concerning the project can be addressed to Professor Jason Smith (jason.smith@materials.ox.ac.uk). General enquiries on how to apply can be made by e mail to graduate.studies@materials.ox.ac.uk. You must complete the standard Oxford University Application for Graduate Studies. Further information and an electronic copy of the application form can be found at http://www.ox.ac.uk/admissions/postgraduate_courses/apply/index.html.

Also see homepages: Jason Smith

*Spectroscopy and modelling of catalyst nanoparticles
Dr R J Nicholls, Dr D Ozkaya^, Dr M Schuster^, Prof P D Nellist (^Johnson Matthey)

The surfaces of catalyst nanoparticles and their interaction with their support dictate their activity and selectivity. A lot of information on organic molecule – nanoparticle-support interaction is ad-hoc and based on mechanisms obtained using indirect averaging techniques. This makes it difficult to get an idea of variation and thus optimise the properties of the catalyst materials. Scanning transmission electron microscopes allow high-resolution imaging and spectroscopy to investigate localised bonding within materials. Earlier this year, the UK SuperSTEM facility received one of a new generation of microscopes which make it possible to do spectroscopy with a 10-fold increase in energy resolution. This increase in energy resolution, combined with first principles modelling, makes it possible to interpret the nanoparticle interactions. This has the potential to completely revolutionise the understanding of catalysis and bring about the localized understanding of interactions of organic molecules with nanoparticles and support. This project will use this cutting-edge technology, along with density functional theory modelling, to investigate the surface of commercial catalyst particles before and after reaction.

This project may be supported by a 3.5 year EPSRC DTP-CASE studentship. If still available this studentship will provide full fees and maintenance for a student classified as home fee status (this includes an EU student who has spent the previous three years (or more) in the UK undertaking undergraduate study).   Further informaiton on the availability of funding can be obtained from Marion Beckett, graduate.studies@materials.ox.ac.uk.  The stipend is expected to be at least £15,000 per year. Other EU students should read the guidance at http://www.materials.ox.ac.uk/admissions/postgraduate/eu.html for further information about eligibility.

 

Any questions concerning the project can be addressed to Dr Rebecca Nicholls or Professor Peter Nellist (rebecca.nicholls@materials.ox.ac.uk or pete.nellist@materials.ox.ac.uk). General enquiries on how to apply can be made by e mail to graduate.studies@materials.ox.ac.uk. You must complete the standard Oxford University Application for Graduate Studies and further information and an electronic copy of the application form can be found at http://www.ox.ac.uk/admissions/postgraduate_courses/apply/index.html.

Also see homepages: Peter Nellist Rebecca Nicholls

PhD Studentship in Materials Chemistry, Electrochemistry and Energy Storage
Professor P G Bruce / Professor M Pasta

A PhD studentship is available for an overseas student to work with Professor Peter Bruce FRS and Professor Mauro Pasta at the University of Oxford on one of the following topics:

  1. The discovery and investigation of new compounds with application as electrodes in lithium and sodium batteries for energy storage. An interest in solid state chemistry or materials chemistry (synthesis and characterization using a wide range of techniques) is required.
  2. The synthesis and investigation of ceramic and polymer electrolytes for lithium-ion batteries. Interest in polymer chemistry, synthesis and characterization is necessary.
  3. To investigate the electrochemistry of Li-O2 cells. Unlocking the performance of this potentially transformational energy storage technology requires an understanding of the fundamental electrochemical processes, e.g. O2 reduction.

Candidates are expected to hold a first class or strong upper second class degree (or equivalent international qualifications), as a minimum, in Chemistry, Materials Science or a related science subject. A masters degree in a related discipline is also desirable.

Candidates will be considered in the University of Oxford’s March 2016 admissions field which has an application deadline of 11 March 2016.

The 3½-year studentship provides full fees at the overseas student rate and a stipend of £14,479 per year in the first year and at least this amount in subsequent years (pro-rata for the final six months). Only candidates classed as ‘overseas’ for fee liability purposes are eligible for this studentship.

Any questions concerning the project can be addressed to Professor Peter Bruce (peter.bruce@materials.ox.ac.uk) or Professor Mauro Pasta (mauro.pasta@materials.ox.ac.uk). General enquiries on how to apply can be made by e mail to graduate.studies@materials.ox.ac.uk. You must complete the standard Oxford University Application for Graduate Studies. Further information and an electronic copy of the application form can be found at http://www.ox.ac.uk/admissions/postgraduate_courses/apply/index.html.

Also see homepages: Peter Bruce Mauro Pasta

(return to list of funded project titles)


OTHER PROJECTS - full details, listed by title

126 projects

Nanomechanical Systems (NEMS) based on Carbon
H. Bhaskaran

Nanoelectromechanical systems (NEMS) are systems where a tiny mechanical element is fabricated to add certain functionality to a device or a system. These systems are functional not only because they occupy less space, but more so because they can perform functions that larger devices cannot or carry out certain tasks with greater precision and efficiency. Our group is seeking DPhil students to carry on this work starting from October 2014. The focus will be on using non-traditional materials, especially amorphous carbon, in NEMS devices. We will also seek to study fundamental aspects of materials science, which will help us create even better devices in future.

An incoming DPhil student will have significant advantages: our experimental capability in this area is now set-up, and we have some of the most advanced instrumentation in the field. Our group has several individuals who can informally work with the student, so the student will not feel lost in their first few months.

Your Profile:
Your profile will be one of a highly motivated undergraduate (evidenced by previous stints in Research laboratories), first class honors degree (or equivalent) earning undergraduate in Physics, Materials, Engineering or a closely related field with a deep desire to carry out independent experimental research. You must like working on hands-on laboratory experiments and have the desire to try out many novel ideas. Evidence (via references) of initiative and ability to work collaboratively would be a plus, as this is an experimental project.

Also see homepages:

3D printing and additive manufacturing approaches for microwave metamaterials
Prof Patrick Grant

Meta-materials are artificial materials that have properties unavailable from single material classes or composites and have been demonstrated in the lab to enable physical phenomena as cloaking, invisibility, advanced communications, energy transfer, sensors and security. Many of the novel properties of meta-materials involve their unusual interactions with electromagnetic radiation such as light and microwaves. However, theorectical designs with meta-materials are outstripping practical demonstration and testing, and there is an urgent need and exciting opportunity to develop new processing approaches to fabricate new, practical meta-materials for engineering applications.

This project focuses on new processing approaches to build active meta-materials with graded dielectric and magnetic properties using 3D printing. An active meta-material is one that can be switched or controlled using an external stimulus such as electricity, magnetism, light, etc, and are at the early stages of development. The project will develop a number of active meta-material ideas suitable for our in-house 3D printing facility, and then design novel arrangements of these materials to make functioning demonstrators at the 5 - 15 cm scale for measurement. The work will involve interaction with designers using simulations and specialists in measurements in the mega-gigahertz range. At all stages, a key aspect will be to characterise the microstructure and performance of the feedstock materials you have developed. The project will also involve developing novel implementations of the additive manufacture process itself in order to allow 3D active devices to be fabricated.

Also see homepages: Patrick Grant

A carbon nanotube quantum computer
Dr E. A. Laird and Professor G. A. D. Briggs

A computer based on the quantum states of single electrons has the potential to be exponentially more powerful for some tasks than existing classical computers. Creating such a computer is an extremely difficult challenge, because quantum states usually decohere rapidly due to interactions with their environment. One leading approach is to use the spin states of an electron in a semiconductor. Carbon nanotubes are a particularly attractive material for this purpose, because nuclear spins, which cause decoherence in some other semiconductors, can be virtually eliminated. In this project, you will create a proof-of-principle two-bit quantum computer in an isotopically purified carbon nanotube. Very recently, a single-qubit gate was demonstrated in a nanotube quantum dot. You will extend this work by using a radio-frequency measurement setup for high-fidelity qubit readout and implementing a two-qubit gate in a pair of quantum dots. The goal is to demonstrate simple quantum algorithms in a carbon nanotube device. This project will involve training in nanofabrication, as well as low- and high-frequency electronics at millikelvin temperatures.

Also see homepages:

A new way to manufacture high performance NbTi superconducting wires
Supervisors: C.R.M. Grovenor/S.C.Speller

The workhorse material for high field superconducting magnets has for many years been a 2 phase NiTi alloy processed by a long and complex thermomechanical process to give a microstructure optimised to give strong flux pinning.  The use of artifical pinning centres to achieve even better superconducting performance has been explored in industry, but rejected because it is too expensive.  Working in the new Centre for Applied Superconductivity, This project will explore an alternative route to give a microstructure that gives strong flux pinning in a simple two-stage process.  The student will be involved in the metallurgical processing, microstructural assessment and superconducting property measurements onthe new alloys, with advice and close interaction from our industrial partners.

Also see homepages: Chris Grovenor Susannah Speller

A unified mathematical approach to stress states in inhomogenous domains
Dr Steve Fitzgerald (Materials), Prof David Hills (Engineering Science)

Although dislocations in most real materials operate in three dimensions, two-dimensional modelling has proved to be a successful and useful endeavour for several reasons. Conditions close to effectively-2D plane strain or plane stress are found in many important engineering applications, and the improved mathematical tractability can allow analytical solutions in certain cases, providing valuable insight lacked by purely numerical approaches. Furthermore, given the great computational complexity of 3D dislocation dynamics, 2D simulations have a far greater scope in terms of the length- and time-scales that can be treated. Dislocations also have widespread application in engineering, where they may be used as kernels in representations of cracks and slip along contact interfaces.

Of particular interest is the stress field generated by a dislocation in a finite or inhomogenous domain. Image stresses due to free surfaces or other boundaries complicate the stress state, and analytical solutions are available only for a few idealized cases. This project aims to apply mathematical methods from the theory of harmonic functions and conformal transformations to significantly extend and generalize the range of available analytical solutions. Potential applications are wide, and include various unsolved problems in contact mechanics, where partial slip is very effectively represented by a glide dislocation array, and it is easy to separate out the effects of slip and separation.  This procedure is exceptionally helpful when studying contact subject to fretting for example, and also the phenomenon of frictional shakedown, where cyclic slip gives way to adhesion because of self-generated interfacial shear tractions.

Also see homepages:

Advanced Gettering of Multicrystalline Silicon for Commercial Solar Cells
Prof PR Wilshaw and Dr S Bonilla

In order to move to a low-carbon future, and avoid the worst effects of anthropogenic climate change, continuing reductions in the cost of renewable energy are required. The semiconductor group at Oxford Materials, in collaboration with international research partners at Fraunhofer ISE in Germany and the University of New South Wales in Australia as well as industry partners, is working to reduce the cost of photovoltaic cells. Graduate students would work as part of a dedicated group of researchers on state-of-the-art techniques for improving the performance of crystalline silicon solar cells, which account for over 90% of all currently manufactured solar cells. Multicrystalline silicon is the most common wafer material for current solar cell production. As multicrystalline solar cell efficiencies increase, recombination due to impurities in the material becomes more and more important. These impurities may be present in the silicon feedstock, or introduced during casting of the multicrystalline ingot. The graduate student will work on developing advanced gettering techniques to remove these impurities from multicrystalline wafers, and on characterizing the improvement in device parameters that may be achieved. This will be done in collaboration with the atom probe tomography unit at Oxford Materials. These technologies may improve the performance of commercial multicrystalline silicon or enable the use of materials currently considered too contaminated for solar cell production. The student would work closely with a range of wafer suppliers, as well as international research partners to ensure the commercial relevance of the work.

Also see homepages: Peter Wilshaw

Advanced Nanoscale Engineering Group - Several Exciting New Applied DPhil Research Areas
Prof H. Bhaskaran

We are now seeking DPhil students in all areas of interest to the Advanced Nanoscale Engineering Group. Please browse through the group's research and publications and contact Prof Bhaskaran for details. Examples of projects available include exciting display applications of phase change materials (see recent news articles linked to on our webpage), artificial retinas and muscles, highly novel and sensitive NEMS, nanomanufacturing as well as nanoscale device manufacture and testing. Although several individual projects are listed with Professor Bhaskaran, the creative student will have the option of tailoring a research in collaboration with the supervisor.

 

Also see homepages: Harish Bhaskaran

Applications of aberration-corrected high resolution electron microscopy
A Kirkland

The department has installed one of the world’s few electron microscopes with aberration correctors in both the condenser (probe-forming) and objective (image forming) lenses and with a unique monochromated electron source. This instrument is capable of recording images with 70pm resolution. Several projects are available that will develop experimental, theoretical and computational techniques for exploiting aberration corrected imaging. Possible materials candidates for experimental and theoretical studies include complex oxide ceramics, surfaces, nanocatalysts and carbon nanotubes.

Also see homepages: Angus Kirkland

Architectures, materials and applications for robust and scalable quantum technologies
Prof. S.C. Benjamin

Today's computers may seem very powerful, but their designs do not take advantage of the enormous potential power of quantum physics. We know that it is possible, in principle, to build an entirely new class of technology that would harness effects like quantum superposition and quantum entanglement in order to profoundly outperform all conventional machines (at least for certain key tasks). However such technologies are very challenging to build in reality. It particular it is difficult to take the small prototype systems in the laboratory and scale them up to the point that they start to exceed the capacities of conventional technologies.  

This project is about finding ways to build quantum technologies that are robust, in the sense that they can operate with realisitic levels of imperfection, and also scalable -- so that once you have a few components working together, it is straightforward to add more and more. The research connects to the new £40M Oxford-led UK Quantum Technologies 'Hub' called NQIT (see http://NQIT.org). There are also opportunities to study potential applications such as quantum machine learning (see http://QuOpaL.org). The research is theoretical in nature, and will suit students who are talented in mathematics and/or physics; the work is applied theory in the sense that it usually links to experimental efforts in Oxford and elsewhere. The webpage of Prof. Benjamin's group is http://QuNat.org.

Also see homepages: Simon Benjamin

Atomic resolution imaging of ultra-thin oxide films
Professor Martin Castell

We are working on a new class of hybrid material that is so thin it is both a surface and an interface. These are oxide films that are one atomic layer thick and can be imaged in the scanning tunnelling microscope with atomic resolution. The structure of the films is unique to the tin film system, is not a bulk termination, and is determined through the interaction with the gold substrate. In this project oxide thin films will be imaged with particular emphasis placed on learning about the point and extended defects that occur.

Also see homepages: Martin Castell

Atomic structure and secondary electron emission
Professor Martin Castell

The most popular method for image creation in the scanning electron microscope (SEM) is to use the secondary electron signal. Until recently it was assumed that secondary electrons are emitted isotropically i.e. with no particular preferred direction, but we now know that the atomic structure of the surface does in fact play a role. This DPhil project is concerned with correlating secondary electron emission using an ultra high vacuum SEM with atomic structure imaged in a scanning tunnelling microscope (STM). Both these techniques are located on the same world-leading instrument in Oxford. The powerful combination of signals will provide a hitherto unexplored path into some very fundamental aspects of nanoscale surface structure. There is also the likelyhood that the experiments will be further expanded through the use of the PEEM instument at the Diamond synchrotron.

Also see homepages: Martin Castell

Batteries for grid-scale energy storage
Prof M. Pasta

New types of energy storage are needed in conjunction with the deployment of solar, wind, and other volatile renewable energy sources and their integration with the electrical grid. No existing energy storage technology can provide the power, cycle life, and energy efficiency needed to respond to the costly short-term transients that arise from renewables and other aspects of grid operation. We are currently working on a new family of insertion electrodes based on the Prussian Blue open-framework crystal structure. This structure is fundamentally different from other insertion electrode materials because of its large channels and interstices. It is composed of a face-centered cubic framework of transition metal cations where each cation is octahedrally coordinated to hexacyanometallate groups and has wide channels between the A sites, allowing rapid insertion and removal of sodium, potassium and other ions. In addition, there is little lattice strain during cycling because the A sites are larger than the ions that are inserted and removed from them. The result is an extremely stable electrode: over 40,000 deep discharge cycles were demonstrated in the case of the copper hexacyanoferrate cathode. 

The student will work on synthesizing new open-framework materials, perform an in-depth structural characterization at the Diamond Light Source and evaluate their electrochemical properties. Collaborations (both internal, external and with Silicon Valley based start-up) are expected.

Also see homepages: Mauro Pasta

Carbon-based quantum devices characterised electrically and by imaging
Dr E. A. Laird, Dr J. H. Warner and Professor G. A. D. Briggs

Carbon nanomaterials are attractive materials for electronic devices, especially for quantum computers using the spin of single electrons. One challenge in realising these applications is that the detailed device structure cannot be fully controlled during fabrication. The aim of this project is to characterize the same devices both through electrical measurements and by high-resolution electron microscopy, with the aim of understanding the electronic properties in terms of the atomic structure.

The goal of project will be to determine how the bandstructure and spin-orbit coupling of carbon nanotubes depend on the atomic structure – in particular on the chirality, which describes how the carbon atoms are aligned. Through aberration-corrected high-resolution transmission electron microscopy (AC-HRTEM), it is possible to measure the chiral indices of individual nanotubes, but so far this has not been performed on nanotubes integrated into electronic devices. You will combine these two kinds of measurement by incorporating a TEM window into existing fabrication technology for ultra-low-disorder nanotubes. You will then make electrical measurements of selected devices in a dilution refrigerator, with the aim of correlating the measured spin-orbit coupling to the previously determined chirality and comparing with existing theoretical predictions.

Also see homepages: Andrew Briggs Edward Laird Jamie Warner

Causal mechanisms of chemotherapy-induced neurotoxicity by mapping local chemistry in the electron microscope
Prof P D Nellist, Dr R Fleck (Kings College London), Dr S Flatters (Kings College London)

Up to 60% of patients receiving standard chemotherapy for various cancers will develop neurotoxicity as a consequence of their treatment resulting in ongoing pain, numbness, tingling and cold/mechanical hypersensitivities in their hands and feet. Chemotherapy-induced neurotoxicity (CIN) is a substantial clinical problem which limits anti-cancer benefits and impacts on patient quality of life and survival. Currently there are no treatments to prevent CIN or effectively treat it once it emerges. Greater understanding of the causal mechanisms of CIN will aid development of novel therapies for this debilitating disorder. In this project the latest cutting-edge spectroscopic techniques in the high-resolution electron microscope will be used to map changes in concentration of key elemental species in the neuronal mitochondria to study the mitochondrial disorder which results from the neurotoxicity. A key aim of the project is to use state-of-the-art technologies developed for materials science and to extend their application into an area to which they have not yet been applied and with the potential for significant impact in healthcare.

Also see homepages: Peter Nellist

Charge sensitive imaging
A Kirkland

“If one knew the positions of all the electrons in a material, there would be no need to find where the nuclei are”. Traditional electron microscopy determines the nuclei positions and we are now aiming to develop methods for locating the electrons. This will revolutionise the study of almost all materials and will provide a new level of structural information for comparison with theoretical models. This project will aim to establish new methods using oxides and low dimensional materials including Graphene as test materials using aberration TEM with advanced image simulation incorporating Density Functional Theory.

Also see homepages: Angus Kirkland

Chip-based atomic clocks
E A Laird / G A D Briggs

Atomic clocks are among the most precise scientific instruments ever made, and are key to advanced navigation, secure communication, and radar technology. We are pursuing a new approach to create a clock that will fit on a chip. Instead of atomic vapours, we will use electron and nuclear spins in endohedral fullerene molecules, whose energy levels offer an exquisitely stable frequency reference. To make this novel approach work, we must overcome a range of physics and engineering challenges, including detecting spin resonance from a small number of spins, identifying the energy levels involved, and miniaturizing the control electronics and magnet. The reward will be a completely new technology with a wide range of civilian and military uses. We are looking for a candidate who has a strong interest in applying quantum physics in new technology, and is motivated to develop the new and demanding electronic measurement techniques that will be necessary.

Also see homepages: Andrew Briggs Edward Laird

Chiral networks and the origin of life
Professor Martin Castell

In this project 2D molecular networks are synthesized through self-assembly on metal and mineral surfaces. Scanning tunnelling microscopy is used to investigate their ordering. In particular, methods will be studied that influence the chirality (handedness) of the molecular arrangements. Examples of this are networks that consist of DNA and RNA nucleobases such as adenine and uracil. These experiments are motivated by the question of what gives rise to a particular chirality in biomolecules such as DNA and amino acids, and as such are relevant to the origin of life.

Also see homepages: Martin Castell

Colloidal Quantum Dot Displays and Lighting
Andrew Watt

Optoelectronic devices made from Colloidal Quantum Dots (CQD) have started to transition from the lab to consumer products, the Sony Triluminous display being a prime example. CQD have great promise in a number of applications, but there are still challenges to be met, primarily methods for continuous production in bulk and lowering the toxicity of the constituent material, and for the integration process of devices and systems. This project focuses on manufacturing process of CQD materials and next-generation smart display/lighting devices based on LEDs.

The latest CQD display technology uses back lit LCD units and Cd based CQD as the phosphor. A second generation of LED driven by electroluminescent (EL) CQD devices (CQD LED) is envisaged to replace current organic LED (OLED) for use in both displays and smart lighting. The main advantage of the CQD LED over OLED are improved reliability/stability, lower production costs, lower power consumption and improved colour purity/gamut. This project is focused on the manufacturing technologies we believe are needed to augment current, and develop additional markets for CQD based companies and also create new businesses.

Also see homepages: Andrew Watt

Colloidal Quantum Dot Photovoltaics
Andrew Watt

The ability to tune the band gap across the solar spectrum through quantum confinement allows the possibility to create broadband multi-junction and multi-band gap solar cells. If this can be harnessed alongside multiple exciton generationand emerging energy transfer mechanisms there is a very real opportunity to break the Shockley Queisser limit. This project will address the challenge of improving device efficiency by using a number of strategies including improving energy level matching and limiting recombination losses by passivation.

Also see homepages: Andrew Watt

Coupling molecular spins to valley-spin qubits in carbon nanotubes
Professor G. A. D. Briggs, Dr J. H. Warner, Dr K. Porfyrakis and Dr E. A. Laird

Carbon-based quantum technologies require the ability to transfer quantum information from one form to another. Valley-spin qubits (so called because of the hybridisation between electron spin states and the valleys in the band structure of the nanotube) enable single states to be manipulated and measured in electron dipole spin resonance, but the coherence times are not long enough for scaleable quantum computing. Molecular qubits are known from ensemble experiments to have useful quantum coherence times, but to exploit these in useful devices we must have ways to measure them individually. By attaching molecules to the nanotube, and transferring quantum states between the nanotube and the molecule, it should be possible to exploit the best of each. The storage time can be increased a further thousandfold by using molecular nuclear spins as a further resource.

Successful development of this scheme will require nanofabrication of the devices, attachment of the spin-bearing molecules, microscopy of the resulting structures, and magnetic resonance at cryogenic temperatures. This project will involve training in nanofabrication, together with electron microscopy and low-temperature electronic measurements. Aspects of the project will be undertaken in collaboration with other members of the laboratory. The goal will be to show that quantum information can be effectively transferred between the nanotube device and the spin states of the attached molecules. This will be achieved by entangling quantum mechanically the molecular spin with an electron spin on the nanotube, and measuring the molecular spin state through its effect on the electron.

Also see homepages: Kyriakos Porfyrakis Jamie Warner

Coupling valley-spin qubits in nanotubes by superconducting cavities
Professor G. A. D. Briggs, Dr E. A. Laird and Dr P. J. Leek*

Carbon-based quantum technologies will use electron spin states in nanotubes as a fundamental resource. A single electron in a confined region (sometimes referred to as a quantum dot) in a nanotube can form a valley-spin qubit, through the interaction between the valleys in the band structure and the spin of the electron. The spin-orbit coupling provides a means of linking the qubit to an external system via an electric dipole.

Quantum technologies will demand the ability to transfer quantum information from one device to another. The magnetic dipole moment of a single electron spin is too weak for this purpose, but by converting it to an electric dipole moment the coupling can be significantly increased. Superconducting cavities, fabricated either in the form of on-chip resonators or as a 3-D box, provide the means to couple two nanotube quantum devices together, or to couple a nanotube device to collective spin states as a quantum information register. The goal of this project will be to learn how to couple a valley-spin qubit to a superconducting cavity, and then to show how that will useful for scalable quantum technologies.

* Department of Physics

Also see homepages:

Defects in diamond as spin qubits in quantum networks
Prof Jason Smith

Diamond has unsurpassed properties for quantum technologies such as quantum sensing and quantum computing, and point defects in the material can act as trapped atoms with properties ideal for the storage and manipulation of quantum states. A major challenge is the efficient coupling of these atom-like systems with optical systems, so that quantum states can be transferred between electrons (or nuclei) and photons to enable the construction of scalable networks. This doctoral project will involve the coupling of single nitrogen-vacancy defects in diamond to optical microcavities in order to maximise the efficiency of quantum state transfer and facilitate scalable networking. You will be part of a small team working towards this goal, which will involve a range of techniques including optical characterisation and spectroscopy, fabrication and handling of diamond microstructures and optical devices, and lasers and cryogenic instrumentation. As such the project is well suited to an energetic and hands-on student who enjoys building apparatus and has a good working knowledge of optics. The project is part of a substantial nationwide program to build scalable quantum networks involving matter systems and photons.

Also see homepages: Jason Smith

Deposition of organic an inorganic layers on polymer substrates by roll-to-roll coating in vacuum
Prof H E Assender

The project will make use of our state-of-the art roll-to-roll polymer web coater to deposit under vacuum acrylate or other organic layers on polymer substrates, followed by evaporation or magnetron sputtering deposition of thin film inorganic layers such as metals or oxides. The resulting materials will then be characterized using a suite of methods. Possible applications include optical coatings, gas barrier films (often for electronics applications), or polymer electronics.

Also see homepages: Hazel Assender

Development of aluminium matrix nanocomposites for high temperature applications
M Galano / F. Audebert

This project  is based on the development of Aluminium Matrix Complex Nanocomposties (AlMCNCs) with combinations of reinforcement strategies at the nanoscale that offer unique properties to target specific applications with an enhancement of combined properties i.e. increase thermal stability, ductility at forging temperature, and higher strength and Young’s modulus in higher performance applications. New materials will be used as nanoreinforcements for improving Young’s modulus and strength of nanoquasicrystalline alloys (NQX). Small Al-particles will be used as a plasticizer for improving the ductility of NQX alloys at forging temperature. These combinations of reinforcement strategies at the nanoscale will create unique complex nanocomposites with a unique combination of properties. Thus, a detailed study on the processing and the mechanisms responsible for microstructural stability and mechanical properties is required to develop these new Al matrix complex nanocomposites and to provide a platform for a disruptive knowledge for designing the right material for each application. Several aspects will be developed within the project: (i)Investigation the different processing routes that lead to obtaining AlMCNCs in bulk shape for industrial applications. (ii)Development of bulk AlMCNCs with different combinations of exciting mechanical properties for producing high industrial impact. (iii)Testing of the new AlMCNCs in real applicationsThe project makes use of processing, microstructural characterisation facilities and expertise and draws on the latest alloy developments within the research group that offer genuine prospects for industrially useful nanomaterials. This project will be within an already running EPSRC/RAEng project that is working on the development of bulk nanostructured alloy alloys and will run with the collaboration of several industrial partners representing a range of interests to pull through developed know-how.

Also see homepages: Marina Galano

Development of metal-metal matrix nanocomposites for hight strength applications
M Galano / F. Audebert

This project is based on the development of Metal Matrix Complex Nanofibril composites using new materials as reinforcements for improving Young’s modulus and strength of nanofibril alloys.  A combination of experimental and simulation studies will be carried out to help understanding of the optimum metal-metal combination, phase fractions, and processing conditions for obtaining the finest nanoparticles and nanofibers size
Several aspects will be developed within the project some of them with help of industrial and academic collaborators:
(i)    Investigation of the different processing routes
(ii)    Development of bulk Metal-Metal Matrix Complex composites with different combinations of exciting mechanical properties for producing high industrial impact.
(iii)    Modelling of the strengthening and deformation mechanisms at the nanoscale in order to predict the mechanical properties of the different composites types.
The project makes use of processing, microstructural characterisation facilities and expertise and draws on the latest alloy developments within the research group that offer genuine prospects for industrially useful nanomaterials. Strong industrial support is already in place for different aspects of the project in particular a company specializing in processing simulations will be carrying out the modelling for the different nanocomposites developed.

Also see homepages: Marina Galano

Development of novel wet chemical techniques towards dedicated nanoparticles manufacturing
Dr. F. Dillon, Professor N. Grobert

Nanomaterials' properties are highly depended on their atomic structure and composition. This project will focus on the synthesis of dedicated nanoparticles defined properties. The student will investigate the influence of various parameters on particle size, shape, concentration and composition. Experiments will involve wet-chemical techniques in conjunction with state-of-the-art electron microscopy techniques. This project is essential to the group and will be an integral part of the ongoing research activities. It will be carried out in close collaboration with Dr K Moh, Prof E Arzt (Leibniz Institute for New Materials Saarbruecken, Germany), and industrial partners.

Also see homepages: Nicole Grobert

Direct electron beam lithography of graphene
J H Warner

Graphene holds a lot of promise for electronic applications. In order to be an effective semiconductor in transistors it is desirable for the width of graphene channels to be sub-10nm. This project will focus on fabricating sub-10nm features in graphene using the novel concept of direct electron beam lithography. Electron beam irradiation will be used to directly sputter carbon atoms from graphene with the aim of fabricating structures for nanoelectronic devices. Graphene structures such as nanoribbons will be produced and implemented in field effect transistors. This will involve fabricating graphene nanoelectronic devices that are compatible with high resolution transmission electron microscopy. Parameters that enable control over the graphene sputtering process will be elucidated. Atomic structure will be gained by aberration-corrected HRTEM and correlated with the electronic device properties.

Also see homepages: Jamie Warner

Dislocation based modelling of engineering alloys
E Tarleton and Prof A J Wilkinson

You will be part of a small dynamic team developing state of the art computational models which are used to simulate a range of micro mechanical tests and microscopy data. This project focuses on simulating delayed hydride cracking in Zr alloys as used in compact nuclear reactors for submarine propulsion. You will simulate the coupled mechanical/hydrogen diffusion process within a discrete dislocation plasticity framework. This will involve developing a FEM code to solve the H diffusion equation, and coupling this with a discrete dislocation plasticity code to simulate dislocation-hydrogen interactions. The majority of the coding will be in Matlab, with the opportunity to learn and use C and CUDA to accelerate the code.

The project will link to experimental work within the wider Materials for Fusion and Fission Power group and may involve interaction with Rolls Royce (Marine).

 

Also see homepages: Edmund Tarleton

DNA sequencing using graphene nanoelectrodes
Dr J. A. Mol and Professor G. A. D. Briggs

Single strand DNA sequencing is a rapidly developing field of research on the cutting edge of physics, biology and chemistry. Solid state nanopores are currently being researched by Oxford Nanopore Technologies to form the basis for next-generation DNA sequencing tools. This includes the evaluation of graphene as a membrane for DNA sequencing applications. There is great need to develop methods for fabricating holes and gaps in graphene membranes that are scalable enough to be part of a production process. We are looking for a DPhil student who will develop suspended graphene devices that have the potential to meet the requirements for solid state nano-pores, and will: 

1. Optimise the nanogap size for analyte molecules of interest.

2. Incorporate our suspended graphene nanogaps into the kind of instrumentation which Oxford Nanopores already uses.

3. Characterise the signals which we can measure from a range of analytes.

4. Seek to improve the geometry in order to optimise the nanogap/nanopore structures for commercial applications.

5. Develop recognition tunnelling as an electronic single-molecule sequencing method for DNA.

The goal is to develop arrays of 10s to 100s of nanopore/nanogap sensing elements integrated with an ASIC for single molecule detection. Following an initial proof of concept, the DPhil student will be working closely with Oxford Nanopore Technologies’ team to manufacture the device at scale and increase the array density to 1000s of channels.

Also see homepages: Andrew Briggs Jan Mol

Electronic and optical properties of metal-halide photovoltaic perovskites
F Giustino / M Filip

Perovskites solar cells are becoming one of the fastest-growing emerging photovoltaic technologies, due to the optimum optoelectronic properties of CH3NH3PbI3 [1,2]: strong absorption in the visible range, long electron and hole difussion length and low exciton binding energy. One of the primary challenges for the future development of optoelectronic devices based on metal-halide perovskites is to achieve a complete theoretical understanding  of their electronic and optical properties.

In our group we are interested in understanding the properties of this relatively unexplored class of materials, such as the electronic and optical band gaps, the effective masses, the optical absorption spectra in the visible and in the infrared, and the transport properties [3,4,5].

In this project we will to explore new strategies for tuning the optical and electronic properties of tin and germanium halide perovskites using rational design. We will perform state-of-the-art electronic structure calculations based on density functional theory and many-body perturbation theory (GW method). Close collaboration with experimental groups is anticipated.

The prospective student is expected to have a strong background in Solid State Physics, and a keen interest in theoretical modelling as well as the study of materials which are technologically relevant for solar energy research. Previous experience with density-functional theory calculations is desirable.

[1] Stranks, S. & Snaith, H. J. Nature Nanotechnology, 10, 391-402 (2015)
[2] Gratzel, M. Nature Materials 13, 828-842 (2014)
[3] Filip, M. R., Eperon, G., Snaith, H. J. & Giustino, F., Nature Communications 5, 5757 (2014)
[4] Filip, M. R. & Giustino, F., Phys Rev B 87, 20, 205125 (2014)
[5] Filip, M. R., Verdi, C. & Giustino, F., J Phys Chem C, 119(45), 25209-25219,  2015

Also see homepages: Feliciano Giustino

Energy extraction from water salinity differences
Prof M. Pasta

The large-scale chemical energy stored as the salinity difference between seawater and fresh water is a renewable source that can be harvested. The entropic energy created by the difference in water salinities (also called “blue energy”) is normally dissipated when river water flows into the sea. This reduction in free energy due to mixing is estimated at 2.2 kJ per liter of fresh water.  We have previously developed a device called a “mixing entropy battery” that efficiently extracts this wasted energy. The device employed sodium manganese oxide and silver as sodium and chloride capturing electrodes respectively. While this device worked well, there are some limitations. Sodium manga has a limited specific capacity (i.e. number of sodium ions storable per gram of active material), while the silver-silver chloride electrode is much too expensive for this application. Moreover, both manganese and silver are heavy metals and their release in seawater is severely regulated. In addition, by operating the mixing entropy battery in reverse we demonstrated the possibility of efficiently desalinating seawater through a device I called a “desalination battery”. The development of the two devices will progress in parallel.

The student will work on new electrode materials as well as improving the design of the device and will be part of an international network working on developing this technology. 

Also see homepages: Mauro Pasta

Engineered Alloys and Nanoparticles for Catalytic Applications
P.A.J. Bagot / M.P. Moody

Heterogeneous catalysts underpin a vital range of industrial applications including exhaust emission control, hydrogen fuel-cells, pharmaceuticals and hydrocarbon production. At the heart of these systems are metal nanoparticles which catalyse the reactions. The overall performance of the catalyst is highly sensitive to the total number of nanoparticles present, their shape, size and also composition when used as alloys. Despite the widespread use of these catalysts the fundamental details of how reactive environments can dramatically alter catalyst surfaces or even strip out expensive metals is not well understood. In this project Atom Probe Tomography will be used to study a range of catalytic alloys and nanoparticles, using custom-built reaction cell facilities to investigate changes to alloy composition at the atomic scale. The student will also be trained to carry out supporting TEM characterisation of catalytic nanoparticles, and will have the opportunity to collaborate with expert project partners working on catalysts synthesis/testing in the University of Lille and UPMC, Paris.

Also see homepages: Paul Bagot

Enhancing 3D Atom Probe Imaging for Nano-Electronic Devices
D. Haley, P.A.J. Bagot, M.P. Moody

Atom Probe Tomography (APT) is a microscopy technique that offers atomic scale spatial and chemical resolution, providing unique insights to an array of materials research programmes. Based upon the physics that underpin the technique, the aim of this project is to design, develop and evaluate a new analytical scheme to reconstruct data obtained from APT experiments, and ultimately significantly improve the quality of images obtained from this microscope.

This projects requires a demonstrated capacity for the solution of applied mathematical problems, good working knowledge of numerical computing, such as a background understanding of multidimensional differential equations and understanding of implementation of numerical solvers. A programming background in numerical computing is essential (e.g C/C++, python, etc.). The student will also be trained to operate the atom probe, enabling data acquisition to support their numerical research The application will be targeted towards high fidelity imaging of nano-electronic devices, such as nm-scale transistors, designed by our industrial collaborators

Also see homepages: Paul Bagot Michael Moody

Epitaxial oxide nanocrystals
Professor Martin Castell

Very small crystals, nanocrystals, of one type of oxide can be grown onto another oxide substrate. The shape, structure, and electrical / optical properties of these nanocrystals is influenced by the strain that builds up between the substrate and the nanocrystal. The idea is to grow an oxide of one type onto a different oxide substrate that has a slight lattice mismatch. The strain that builds up in the oxide nanocrystals will then affect the electronic properties such as the bandgap. This is called strain engineering, and has been carried out for many years in the semiconductor industry with e.g. germanium on silicon systems. In this project the scope of strain engineering will be expanded into the realm of oxide materials. We have some exciting preliminary data of Mn3O4 and TiO2 nanocrystals on SrTiO3 substrates that show the feasability of the proposed work.

Also see homepages: Martin Castell

Experimental Validation of Crack Propagation Criteria under Mixed Mode Loading
James Marrow

To accurately predict crack paths in brittle materials, it is important to properly address the effect of mixed mode loading in multi-axial stress states.  Predictive models exist, and their experimental validation needs support from direct measurement the crack tip strain fields for comparison with the predicted strain fields; the latter are currently used to predict the crack path.  Discrepancies are expected due to material microstructure effects such as aggregate interlocking (from shear loading), for instance.  We have developed tools so that direct measurement of crack tip displacement fields can be used to calculate the stress intensity factor, via the J-integral.  This is done by injecting the measured displacements as boundary conditions into a Finite Element mesh; the displacement field is obtained by digital image correlation.

This project will apply these methods to examine the crack propagation criteria in brittle materials, such as the polygranular graphite used in current and next generation nuclear reactors.  The project will also investigate the relationships between the applied stress state, the local strain fields and the crack propagation path.  This experimentally-based study will support the ongoing modelling and experimental studies in industry; an EPSRC iCASE studentship with industry may be available.

The project is suitable for students with an engineering, physics or materials background and will involve techniques such as digital image correlation, finite element modelling and computed X-ray tomography.

Also see homepages: James Marrow

Explaining dislocation motion by the 3D measurement of core structures
Prof P D Nellist

The dislocation is a key crystal defect that controls how materials can deform.  In some materials, for examples the tungsten used in fusion reactors, the certain types of dislocations can behave in unusual ways.  For example, screw dislocations can have low mobility making the materials much more brittle.  The explanation of this unusual behaviour probably lies in the detailed atomic arrangement at the core of the dislocation, but a full 3D characterisation of such defects has not before been possible.  Here we make use of a novel “optical sectioning” procedure we have developed to determine the structure of dislocations in 3D.  Using this approach to relate atomic structure to materials properties allows the rational design of alloys to improve the ductility of important structural materials.  The project will involve using state-of-the-art atomic resolution electron microscopes, developing new imaging and data processing methods, and modelling crystalline defects.

Also see homepages: Peter Nellist

Exploiting extrinsic passivation on antireflection coatings for high efficiency silicon solar cells
Supervisors Prof PR Wilshaw and Dr S Bonilla

In order to move to a low-carbon future, and avoid the worst effects of anthropogenic climate change, continuing reductions in the cost of renewable energy are required. The semiconductor group at Oxford Materials, in collaboration with international research partners at Fraunhofer ISE in Germany and the University of New South Wales in Australia as well as industry partners, is working to reduce the cost of photovoltaic cells. Graduate students would work as part of a dedicated group of researchers on state-of-the-art techniques for improving the performance of crystalline silicon solar cells, which account for over 90% of all currently manufactured solar cells.

Silicon solar cells capture solar energy when light is absorbed near the cell’s surface. The surface of the cell represents a major material defect where loss of charge carriers may occur. The reduction of charge loss at the surface, termed passivation, is hence a critical feature requiring improvement. For solar energy to be cost competitive with other technologies, manufacturing costs of solar cells must be brought down while maintaining device performance. This project aims to explore a new generation of cost effective dielectric coatings that provide optimal passivation using the technologies proposed and patented by the group, as well as improving the optical qualities over current industrial films. The student performing the work will be involved in deposition of dielectrics using semiconductor facilities and characterisation of their properties using electronic techniques. These films will then be extrinsically treated to exploit their passivation characteristics.

Also see homepages: Peter Wilshaw

Exploring low energy excitations with electron microscopy
Dr R J Nicholls, Dr J R Yates, Prof P D Nellist

In the last two years advances in electron microscopy have given us the opportunity to revolutionise our understanding of catalysts, defects and functional materials.  This can be achieved by using electron energy loss spectroscopy to probe the low-energy excitations within advanced materials.  A new generation of electron microscopes are able to combine atomic resolution imaging with high resolution electron energy loss spectroscopy, allowing vibrational spectroscopy at atomic resolution and the ability to carry out precise bandgap measurements with spatial resolution.  These advances will benefit the study of catalyst particle surfaces and materials such as transparent conducting oxides.  The first of these new microscopes in Europe was unveiled at the UK SuperSTEM facility earlier this year.  The project will make use of this new facility to address some of the fundamental questions rising from these new experimental capabilities, as well as applying this new technique to answer cutting-edge materials problems.

Also see homepages: Rebecca Nicholls

Fast pixelated detectors for STEM: a paradigm shift in atomic imaging
Prof P D Nellist (in collaboration with the University of Glasgow)

The research proposed here aims to develop entirely new ways of imaging in the scanning transmission electron microscope (STEM), and to use these methods to study materials problems.  The overarching aim that forms the basis of the project is to use recently developed fast pixelated detectors to record two-dimensional diffraction patterns as a function of the position of a focused, atomic-scale, electron beam performing a two-dimensional scan.  The resulting four-dimensional data set is the ultimate STEM imaging experiment.  Such a rich dataset contains information about the phase shift that results from transmission through the sample.  Using an approach similar to holography, information about the composition of the sample, the strain in the sample and the three-dimensional ordering in the sample can be measured.  These developments will allow new types of materials to be observed at atomic resolution and new types of measurements about materials to be made.  The project will involve developing skills ranging from fundamental studies of electron scattering processes to statistical methods and parallel computing along with developing the appropriate experiments on the microscope.

Also see homepages: Peter Nellist

Fatigue Crack Initiation in Ti alloy Linear Friction Welds
Prof Angus J Wilkinson and Dr Jicheng Gong

We have developed novel methods for very rapid (~106 cycles in 1 min) fatigue testing of very small (~0.5 to 200 µm across) material volumes. This has opened up new possibilities for studying fatigue crack initiation in (very) high cycle fatigue. In this project the method will be used to examine fatigue crack initiation in Ti-6Al-4V linear friction welds - the key technology in manufacture of bladed disks 'blisks' for areoengines.  During linear friction welding very intense but localised heating is generated and followed by rapid cooling as the process stops which leads to very dramatic changes in microstructure over a narrow weld region. The new testing method will allow individual parts of this microstructure to be isolated and its fatigue response established. We aim to provide a very complete analysis of the weld zone's fatigue behaviour and link it to microstructural variation and processing conditions.

This project will be carried out in close conjunction with Rolls Royce and will link to activities under the flagship EPSRC HexMat programme grant.

Also see homepages: Angus Wilkinson

Flash sintering
R I Todd

Normally, it takes several hours at a temperature in excess of 1000 C to sinter a ceramic. However, it has recently been discovered that this can be achieved in a few seconds with furnace temperatures below 1000 C by applying an electric current to the specimen whilst it is heated. We have successfully repeated the result and have established that the "flash event" originates in a thermal runaway effect. The project aims to investigate and exploit the rapid sintering and deformation which accompanies the power surge of the flash event.

Also see homepages: Richard Todd

Fundamentals of Fatigue Crack Initiation
Prof Angus J Wilkinson

The development within the group of the high resolution EBSD method provides a route to map the intra-granular distributions of local stress and dislocation density in a routine way. This project will exploit this development in trying to gain insight into cyclic deformation leading to fatigue crack initiation. Polycrystals processed to give different characteristic length scales will be examined at various points through the early stages of fatigue. The formation of 'hot spots' of high stresses and/or high dislocation density will be characterised. We will also attempt to identify local microstructural features that tend to encourage hot spot formation and crack initiation.  

Also see homepages: Angus Wilkinson

Graphene based 2D nanoelectronics
Jamie Warner

Graphene has exceptional electronic properties, combined with a 2D structure that makes it attractive for a wide range of electronic applications. Other 2D crystals such as MoS2 and BN have similar 2D structure, but are semiconducting and insulating. This project will focus on the fabrication and characterization of nanoelectronic devices such as field effect transistors and ultrathin optoelectronic devices using 2D crystals. It will involve working in a clean-room environment using electron beam lithography to fabricate nanostructured electrodes and the patterning of graphene from the top down. The graphene and other 2D materials will be available within the group and are grown by chemical vapour deposition. The aim of this project is to solve processing and materials issues that currently limit the potential of 2D materials in electronics.

Also see homepages: Jamie Warner

Graphene based sensors and actuators
H. Bhaskaran

Graphene has been around for a bit now, and technology is reasonably advanced in order for reasonable quality graphene to be procured commercially. However, the ability to make devices and test them is sorely lacking. Even worse is the inability to integrate graphene with other functional materials to make real nanoscale devices that actually perform important tasks. In this project, we will specifically target projects related to directly patterning graphene to make nanomechanical resonators. Our group has been gaining much expertise in reaching very high mass sensitivities using such sensors (mass less than a He atom), and we are seeking a DPhil student that can actually integrate sensing functions into arrays of such sensors.

Your Profile and application
Your profile will ideally be one of a highly motivated researcher (evidenced by previous stints in research groups or labs), having (or predicted to earn) a first class honors degree (or equivalent) undergraduate/masters in Physics, Materials, Engineering, Chemistry or a closely related field with a deep desire to carry out independent experimental research.  You must enjoy hands-on laboratory experiments and have the desire to try out many novel ideas.  Evidence (via references) of initiative would be a plus, as this is an experimental project.

Also see homepages:

Graphene electrodes for nanocrystal solar cells
Jamie Warner and Andrew Watt

Graphene is an ideal 2D material for utilization as a transparent conducting electrode in photovoltaics (solar cells). High efficiency photovoltaic devices will require the effective integration of other nanomaterials with graphene to produce hybrid nanosystems. Inorganic nanocrystals such as PbS, ZnSe, TiO2 and Si, have unique semiconducting properties with band gaps that span from the near-IR to UV. This project will focus on synthesizing inorganic nanocrystals using solution-phase chemistry. Control over the shape to tailor spherical, rod and branched structures will be investigated. Variation of surface state morphology will be conducted through various chemical approachs to control the inter-nanocrystal interactions. Synthetic graphene will be produced using chemical vapour deposition. Composite hybrid devices will be fabricated that use synthetic graphene as a working transparent conducting electrode and the inorganic nanocrystal as the active functional nanomaterial.

Also see homepages: Jamie Warner Andrew Watt

Graphene ribbons for nanoelectronics
Dr. A.A. Koos, Professor N. Grobert

Controlling the structure and hence properties of nanomaterials is essential for their successful implementation in devices. This project will focus on the generation of graphene ribbons and their detailed characterisation using state-of-the-art in-situ characterisation techniques.

Also see homepages: Nicole Grobert

Growth and spectroscopy of metallic nanocrystals and clusters
Professor Martin Castell

Nanometre sized metal islands on oxide supports are used in diverse applications from catalytic materials to gas sensors. Interaction between the oxide support and the islands, the island shape, the temperature dependence of island ripening, and molecular interactions with the islands are all active areas of study. In this DPhil project a variety of transition metal clusters on single crystal oxide supports will be investigated. The atomic structure of the nanocrystals will be imaged with scanning tunnelling microscopy, and their electronic structure will be probed using optical spectroscopies.

Also see homepages: Martin Castell

Hierarchical nanostructures for energy applications
Dr. F. Dillon, Dr. A.A. Koos, Professor N. Grobert

This project will aim to develop fast, facile, and inexpensive routes to manufacturing hierarchical inorganic nanostructures for energy applications. Various production techniques and combinations of these will be explored including hydrothermal methods, chemical vapour deposition techniques, and wet chemistry.

Also see homepages: Nicole Grobert

High Temperature Micro-mechanical testing of Zirconium for Nuclear Fission Applications
Dr D.E.J. Armstrong, Professor A. J. Wilkinson

Zirconium alloys are widely used in nuclear fission reactors in fuel cladding, where its mechanical performance is key to ensure safe operation of the reactor. However there is a lack of basic mechanical data on these alloys at both reactor specific temperatures, and with controlled, known levels of oxygen, both of  which are needed for improved alloy processing and reactor design.

This project will utilize and further develop novel micro-mechanical techniques, based on FIB machined test samples such as pillars and cantilevers, to measure key mechanical parameters such as Young’s Modulus, critical resolved shear stress, and slip system activity. The world leading Variable Temperature Nanoindenter, recently installed in Oxford, will be used to carry out these tests at elevated temperatures and advanced finite element modelling used to extract the key mechanical properties from the tests. Work will be carried out on pure alpha zirconium as well as samples with intentionally increased oxygen content. The data produced will be used to improve the modelling of zirconium alloys in the nuclear industry. This project will be carried out in close conjunction with Rolls Royce and the other partner Universities in the flagship EPSRC HexMat programme grant.

Also see homepages: David Armstrong

Hydrogen Passivation of Defect Engineered Silicon Solar Cells
Prof PR Wilshaw and Dr S Bonilla

In order to move to a low-carbon future, and avoid the worst effects of anthropogenic climate change, continuing reductions in the cost of renewable energy are required. The semiconductor group at Oxford Materials, in collaboration with international research partners at Fraunhofer ISE in Germany and the University of New South Wales in Australia as well as industry partners, is working to reduce the cost of photovoltaic cells. Graduate students would work as part of a dedicated group of researchers on state-of-the-art techniques for improving the performance of crystalline silicon solar cells, which account for over 90% of all currently manufactured solar cells. While multicrystalline silicon is currently the most cost effective material for the fabrication of solar cells, the high levels of defects and impurities present in this material limits the cell efficiencies that can be obtained. This is mostly through recombination of excited charge carriers at defect sites in the silicon bulk. The two most common approaches for reducing bulk recombination in crystalline silicon solar cells are defect engineering via gettering and hydrogen passivation. While both approaches are capable of reducing the recombination rate by more than an order of magnitude they are typically optimized separately. The graduate student would work in close collaboration with the world-leading hydrogen passivation group at the University of New South Wales to develop and apply hydrogen passivation techniques to defect engineered silicon. This would allow observation of how gettering techniques affect the ability of hydrogen to passivate the impurities remaining in the silicon and subsequently address optimization of both processing techniques.

Also see homepages: Peter Wilshaw

Image reconstruction techniques for super-reconstruction electron microscopy
A Kirkland

We are developing techniques for reconstructing the exit wavefunction of various specimens from images recorded with different focus values or with different illumination tilts. In this way it is possible to obtain fully quantitative structural data at higher resolution than the instrinsic limit set by the optics of the electron microscope. This project will apply this approach to a variety of nanomaterials with the aim of understanding their structure property relationships at higher spatial resolution than is otherwise possible.

Also see homepages: Angus Kirkland

Improving melt cleanliness
K A Q O'Reilly

Most metals have, at some stage in their processing, been in the liquid state. Such metallic melts can be chemically dirty (containing impurities and dissolved gases) and physically dirty (containing unwanted hard particles, oxide films etc). It is now becoming accepted that the cleanliness of a melt can significantly influence the ease with which a melt can be handled and cast, and the properties of the final components into which it is made. This project will investigate the effect of melt cleanliness in Al alloys. Novel intrinsic and extrinsic methods will be developed, including chemical doping and thermal excursions of the melt, in order to improve melt cleanliness. Melt cleanliness will be measured in-house both directly in the melt and by investigating the effect on primary grain size and properties. The effectiveness of these novel methods will be compared to current industrial methods such as rotary flux degassing and filtration. The overall aim is to develop new methods for improving melt cleanliness which are both quicker and cheaper than existing technology, while being suitable for use on an industrial scale.

Grain refiner additions, impurity levels and melt cleanliness have all recently been shown to individually affect secondary intermetallic phase selection in Al alloys. In turn, the type, size and morphology of such intermetallics can significantly affect the ability to carry out downstream processing and the mechanical properties of final components. This project will investigate the effects of combining these and other factors (such as solidification conditions) in order to determine the dominant factors affecting intermetallic selection under more realistic, commercially relevant conditions.

Grain refiner additions, impurity levels and melt cleanliness have all recently been shown to individually affect secondary intermetallic phase selection in Al alloys. In turn, the type, size and morphology of such intermetallics can significantly affect the ability to carry out downstream processing and the mechanical properties of final components. This project will investigate the effects of combining these and other factors (such as solidification conditions) in order to determine the dominant factors affecting intermetallic selection under more realistic, commercially relevant conditions.

Also see homepages: Keyna O'Reilly

In situ study of atmospheric stress corrosion cracking in engineering alloys under controlled humidity environments
James Marrow and Marina Galano

Stress corrosion cracking of engineering alloys, such as stainless steels and high strength aluminium, can occur gradually in specific conditions of controlled humidity and temperature - if a salt deposit is present.  To predict the lifetime of structural components, it is very important to understand the kinetics of both crack initiation and crack propagation.  However, the presence of the corrosion deposit makes direct observations difficult, particularly of the early stages of crack development. 

This project will investigate the effects of surface finish and applied stress, utilising digital image correlation (DIC) to detect the onset of stress corrosion cracking and quantify its propagation during long term tests. Previous studies have demonstrated that DIC can detect cracks beneath the corrosion deposit.  A key objective will be to apply a novel method that injects the measured crack tip displacement field into finite element analysis software to obtain the crack's strain energy release rate - this describes the mechanical driving force that is responsible for crack propagation.  Combined with local measurements of the crack tip opening displacement, the aim is to understand the influence of mechanical factors in the early stages of stress corrosion cracking in engineering alloys.  The use of X-Ray computed  tomography and digital volume correlation to study cracks in three-dimensions will also be explored.

The project is suitable for students with s background in engineering, materials science or physics.

Also see homepages: James Marrow

Insulating and Semiconducting 2D crystals for electronic applications
Jamie Warner

Graphene is a semi-metal 2D crystal, Boron Nitride (BN) an insulating 2D crystal, and MoS2/WS2 are semiconducting 2D crystals. Realizing the potential of 2D crystals in electronic applications requires all 3 of these variants. We have undertaken years of research in growing graphene crystals by chemical vapour deposition and can now produce high quality materials. However, further improvement is needed to advance the synthesis of BN and MoS2/WS2 2D crystals to obtain similar quality films. In this project 2D crystals will be synthesized by chemical vapour deposition to produce materials with varying band structure. New synthetic strategies will be developed in order to produce large single crystal structures on a variety of substrates compatible with device processing. The atomic structure of the new 2D crystals will be characterized using advanced electron microscopy (scanning electron microscopy and transmission electron microscopy). The electronic properties of the new materials will be analysed by fabricating nanoelectronic devices such as transistors. This is a unique opportunity to undertake a project involving new materials synthesis, characterization of the atomic structure, and implementation in nanoelectronic transistor arrays. The project is well integrated into the group's goals by developing new 2D crystals that will have large up-take amongst other researchers for applications ranging from flexible electronics, pressure sensors, optical detectors, LEDs and solar cells.

Also see homepages: Jamie Warner

Integrating Inorganic Nanocrystals into Graphene Devices
Jamie Warner

Utilizing graphene in opto-electronic devices will require the effective integration of other nanomaterials to produce hybrid nanosystems. Inorganic nanocrystals such as PbS, ZnSe, TiO2 and Si, have unique semiconducting properties with band gaps that span from the near-IR to UV. This project will focus on synthesizing novel inorganic nanocrystals using solution-phase chemistry. Control over the shape to tailor spherical, rod and branched structures will be investigated. Variation of surface state morphology will be conducted through various chemical approachs to control the inter-nanocrystal interactions. Synthetic graphene will be produced using chemical vapour deposition. Composite hybrid devices will be fabricated that use synthetic graphene as a working transparent conducting electrode and the inorganic nanocrystal as the active functional nanomaterial. Viability in photodetectors and photo-catalysis will be explored.

Also see homepages: Jamie Warner

Investigation of atomic structures of bioactive glasses for biomedical applications
A I Kirkland / K Borisenko

Bioactive glasses play a key role in bone tissue engineering due to their ability to form strong bond with the living tissues . This is often related to the ability of such glasses to precipitate bone-compatible hydroxyapatite phasesat rhe surface. It is also  observed that their bioactivity can be modified by various additives or dopants. However, the mechanisms of the hydroxyapatite formation and the influence of dopants/additives and composition of the glass on  hydroxyapatite precipitation are poorly understood. This is in part related to the fact that there is no reliable experimental information on structures of such glasses. In the project we will study the atomic structures of various bioactive glasses prepared by different methods and containing different additives using advanced electron selected area and nanodiffraction, reduced density function (RDF) analysis, imaging and modelling methods.

Also see homepages: Angus Kirkland

Layer-by-layer manufacture of improved materials and devices for energy storage
Prof Patrick Grant

New ideas for manufacturing the electrodes used Li ion batteries, electrochemical supercapacitors and permeable fuel cell membranes are being investigated to produce improvements in one or more of energy density, power density, cycle life, safety and reduced cost.  The research involves developing new ideas and equipment for layer-by-layer fabrication of the various parts of these devices, with each layer optimised for its specific function and location in the device - and is quite different for the very productive but simplistic and constraining processes used currently in industry. For example, in this project LbL processing will be used to adjust the electrode microstructure progressively during fabrication to improve ion mobility from place to place in the electrode, to reduce charge and discharge times for electric vehicle applications. LbL processing will also be investigated for its ability to transform cheap, safe but previously considered unpromising materials into efficient electrochemical storage materials for very large, grid scale storage applications. The project will involve a combination of processing and equipment development, microstructural characterisation and energy storage measurements.

Also see homepages: Patrick Grant

Making and manipulating metal nanowires inside carbon nanotubes
Professor N. Grobert

Ferromagnetic nanowires have attracted much interest and are widely used across different disciplines, including biology and medicine. In preliminary experiments, ferromagnetic nanoparticles and -wires have proven to be highly efficient for manipulating nano- and micro-scale objects. Recently it has been shown that carbon nanotubes (CNTs) can be filled during growth with pure metals and alloys simply by varying catalyst concentration. The carbon coating prevents nanowire oxidation making them easy to handle.

This project is aimed at the production of metal-filled carbon nanotubes, their structural characterisation using state-of the art analytical electron microscopy. The project will be carried out in close collaboration with Professor Toru Maekawa (Bio-Nano Electronics Research Centre, Toyo University, Japan). The candidate will have the opportunity to interact with researchers based at the Bio-Nano Electronic Research Centre and will be participating at the 21st Century's Centre of Excellence Programme on Bioscience and Nanotechnology.

Also see homepages: Nicole Grobert

Manufacturing and characterization of new light weight alloys
M. Galano/ F. Audebert

The design of new light weight materials (Al and Mg based) is of extreme importance to industry due to the constant need to develop materials that combine high strength and light weight. This project is based on the development of new alloys systems by means of diverse rapid solidification techniques achieving cooling rates of 10 6 K/s. These rapid solidification techniques allow obtaining microstructures that combine several stable and metastable phases such as amorphous, quasicrystalline and crystalline phases opening wide range of alternative phases to be able to produce innovative light weight alloys for demanding applications. Materials are going to be characterised by X- Ray analysis, calorimetry and electron microscopy techniques. The evolution of the microstructure is going to be studied by means of heat treatments, structural characterisation and mechanical testing in order to understand the phase transformations and the potential properties for structural applications.

Also see homepages: Marina Galano

Mapping fluorescent markers in biological samples using low-loss electron energy-loss spectroscopy
Prof P D Nellist, Dr Roland Fleck (Kings College London)

Fluorescence microscopy in light microscopy is a very common technique because it allows the molecular composition of biological structures to be identified through the use of fluorescently-labelled probes of high chemical specificity such as antibodies. Observation of sub-wavelength structures with light microscopes is difficult because of the Abbe diffraction limit. Green light at around 500 nm has an Abbe limit of 250 nm larger than many relevant cellular structures. Resolution is further degraded by detector sensitivity (increasing noise at the expense of signal), wide spread use of signal amplification (reducing spatial resolution) to improve detection and scattering of light. Recent developments in spectroscopy in the electron microscopy now allow optical excitations to be observed with nanometre-scale spatial resolution. The aim of this project is to attempt for the first time to apply these electron microscopy methods to fluorescently-labelled biological structures, creating an entirely new method for characterising biological structures.

Also see homepages: Peter Nellist

Mechanism and Modelling of Superplastic Deformation
R.I. Todd, A.J. Wilkinson,

§ Superplasticity is a phenomenon in which metals and ceramics can exhibit spetacularly large tensile elongations to failure under certain conditions (the world record approaches 10 000!). By using submicron surface marker grids we have recently shown conclusively that superplastic deformation takes place by stress-directed diffusion and does not involve significant lattice dislocation activity under optimum conditions. This has made a clear step forward in the understanding of the phenomenon and has settled the 75 year old question of how grain boundary sliding is “accommodated” at grain boundary triple lines. At the same time, this advance raises a new set of questions, and in particular why the kinetics of superplasticity do not correspond to those of classical diffusion creep. This project aims to answer these questions by expanding our surface studies to different materials and different deformation regimes. A further aim is to incorporate this new understanding of superplasticity into improved modelling of superplastic forming. The research will involve Focused Ion Beam milling and mechanical testing in the SEM over a range of temperatures and nanoindentation.

Also see homepages: Richard Todd

Mechanisms for the control of fatigue resistance of advanced lightweight nano-composites
James Marrow, Marina Galano, Fernando Audebert

This project is concerned with the role of microstructure in the fatigue resistance of novel high strength Light weight nanostructured alloys. A new family of rapid solidified alloys show good mechanical properties with combined high strength and low density, these alloys have the potential to be used in pistons in car engines and replace Ti-alloys in gas turbines; the consequent reduction in weight and inertial forces will reduce fuel consumption and increase power output.

Tests performed to data show these alloys have very good fatigue resistance, but there have been no fundamental studies to investigate the mechanisms for this; the hypothesis is that initiated fatigue cracks are arrested at interfaces between the matrix and reinforced zones.  If so, then the strain paths arising from process variations during forging may have a significant effect on microstructure and the local fatigue properties.  To study this, a range of microstructures of a nanostructured Al alloy obtained by different heat treatments and processing conditions  will be produced and tested to correlate fatigue crack initiation and growth with the microstructure; importantly the interactions between arrested fatigue cracks and local microstructure will be studied using advanced electron microscopy, including high resolution EBSD and TEM of FIB-milled selected regions, to develop mechanistic models for fatigue resistance.

Also see homepages: Marina Galano James Marrow

Metal matrix composites produced by semi-solid processing
K. O'Reilly / M. Galano / F. Audebert

The aim of this project is to use semisolid processing to obtain novel graded properties and selective local reinforcement of Al alloy components. The processing is based on the rapid induction heating into the semi-solid state of cylindrical slugs of materials containing various fine-scale complex microstructures. Stacking of slugs of various compositions will be used to obtain the gradation in properties or local reinforcement. Semi-solid material will subsequently be injected into an Ube 350 tonne New Rheocaster to produce components. Semi-solid techniques are known to produce small, equiaxed, non-dendritic grains resulting in an increase in the toughness of the material.Materials manufactured by this route will be suitable for use at a wide range of temperatures, dependent on the the Al alloy system. The applications the project will be focusing on are engine blocks and automotive and machine components.Different types of nano-sized reinforcements will be used in order to optimise the properties achieved in the final components. The fine scale complex microstructures of the composites obtained will need to be characterised at the different stages of the processing to gain an understanding of the processing/microstructure relationship and the microstructural evolution, to provide a platform to control the complex microstructures and to understand mechanical behaviour.

Also see homepages: Marina Galano Keyna O'Reilly

Metal Nanowires for Optoelectronics
Andrew Watt

Transparent conductors are part of life from iPod touch screens to solar cells. Current technologies utilise doped metal oxides, however the constituent materials and processing method are expensive and not applicable to a wide range of substrates (eg plastics). This project will involve the synthesis of metal nanowire alloys, thin film processing on a variety of substrates, conductivity and mobility measurements along with physicochemical characterization eg XRD, SEM, XPS, TEM.  The last stage of the project will be to apply the new materials in photovoltaic and LED devices.

Also see homepages: Andrew Watt

Micromechanics
S G Roberts / A J Wilkinson / R I Todd

We have demonstrated over the last two years that focussed ion-beam (FIB) machining can be used to produce specimens for mechanical testing on a length scale of microns to tens of microns. These can then be imaged using a nanoindentation system in AFM mode and loaded to produce a load-displacement curve from which stress-strain data can be derived. This type of testing only became possible with the advent of precision FIB equipment, and is greatly facilitated by the use of the recent dual-beam (electron & gallium) instruments that allow imaging without simultaneous cutting & damage. The Oxford group is one of thee groups worldwide (the other two being in the USA and in Austria) currently leading in this new and very rapidly-developing area. For the first time, we can make quantitative studies of mechanical behaviour at the scale of materials’ microstructures, the scale that control their behaviour. These techniques will form an integrated part of many of the “fusion reactor materials” projects. We have devised specimen geometries that contain only the thin ion-irradiated layer in the deforming region of the specimen, and have shown that we can obtain full stress strain curves of irradiated materials from such specimens. In other aspects of micromechanical testing, we are now looking to recruit researchers to develop these new techniques and to apply them to the understanding of the microstructural basis of the mechanical behaviour of materials.In particular, we aim to initiate projects focussing on: Factors controlling the strong size-effects on yield and work-hardening in micro-cantilever, micro-tension and micro-compression specimens; Technique and equipment development, especially to low  and high test temperatures and use of controlled test environments Characterising stress-corrosion cracking rates as a function of stress and boundary character for individual grain boundaries in steels; Mechanical behaviour of microporous materials; Grain boundary strength and sliding in superplasticity; Grain boundary embrittlement in ferritic steels; strength and toughness of individual grain boundaries in engineering ceramics. Funding may be available (for UK/EU applicants), depending on the outcome of some currently pending research grant applications.

Also see homepages: Steve Roberts Richard Todd Angus Wilkinson

Microstructural analysis of irradiated nuclear fuel cladding alloys
Professor Chris Grovenor

Over the past several years we have developed novel techniques for the study of the microstructure and nano-chemistry of zirconium fuel cladding alloys exposed to aqueous corrosion.  However, these techniques have rarely been applied to materials exposed to neutron irradiation damage. This project will design and carry out experiments on ex-reactor materials provided by our project partners in Westinghouse and Canadian Nuclear Laboratories to explore how irradiated materials differ from those corroded in an autoclave.  The student will become an expert user of high resolution TEM techniques and there will be opportunities to work closely with leading international nuclear companies in the design of improved alloys that will enable the more efficient use of nuclear fuels.

Also see homepages: Chris Grovenor

Microstructural control of Al alloys using intrinsic oxides
K O'Reilly

The world produces 37 million tons of Al every year. All of this metal will have grain refiner additions made to it to promote the nucleation of a fine primary Al grain size.
Oxide particles exist in nearly all liquid metals and alloys exposed to air or even under protective atmospheres. Oxide particles are often considered harmful inclusions since they reduce castability of alloy melts, deteriorate ductility and fatigue strength of castings and cause severe difficulties in down stream processing of continuous cast feedstock. As a result, considerable effort is expended to prevent oxide formation and to clean the melt by expensive melt filtering. However, recent research work at Brunel has demonstrated that by liquid metal engineering they can not only eliminate the harmful effects of the oxides but also make positive use of them for effective enhancement of nucleation for structural refinement of the Al grains, so reducing the need for grain refiner additions.
Work in Oxford has demonstrated that grain refiner additions not only nucleate the Al grains, but also control intermetallic selection in Al alloys, hence modifying mechanical properties. This project will investigate the potency of oxide particles for heterogeneous nucleation of intermetallics. The nucleation sequence of various intermetallic phases due to unavoidable oxides and their control will be studied during solidification of Al-alloys. A phase extraction technique will be used to facilitate the detailed characterisation of intermetallic phases and their interaction with extrinsic and intrinsic alloy additions. Special reference will be made to inclusions and impurity elements in recycled materials.

Also see homepages: Keyna O'Reilly

Multi-component molecular crystals
Professor Martin Castell

The surfaces of a variety of nanostructured oxides can be used to order molecules, such as fullerenes (e.g. C60, C70), into specific two dimensional patterns. This is called templated molecular ordering. In this DPhil project fullerenes of different sizes will be mixed together to give rise to molecular alloys. Specific concentrations and relative sizes of fullerenes are thought to form ordered systems. The structure of these molecular alloy crystals will be studied at atomic resolution with scanning tunnelling microscopy. Ultimately the idea is to create molecular architectures that can be used in advanced electronic devices.

Also see homepages: Martin Castell

Nanocrystalline metal and metal oxide catalysts
A Kirkland

Nanocrystalline metal and metal oxide particles play a key role in catalysis. This project aims to characterize these materials, and in particular their surfaces and shapes using combinations of high resolution imaging and three dimensional tomographic reconstruction. The project will also involve interactions with theoretical modelling groups and for suitable systems prototype catalytic studies. 

Also see homepages: Angus Kirkland

Nanomaterials for quantum technologies
Professor G. A. D. Briggs, Dr K. Porfyrakis, Dr J. H. Warner and Dr E. A. Laird

Quantum information processing offers one of the most exciting challenges in the study and development of nanomaterials. It is at the cutting edge of quantum nanoelectronics, and Oxford is part of the world-wide endeavour to develop scalable quantum computers. Instead of classical bits of information, these will work with qubits (quantum bits). We need materials with quantum states that can be individually controlled and measured, and yet which are sufficiently robust against decoherence that they can sustain a sequence of quantum manipulations and interactions. We lead the world in using the new family of fullerene materials (popularly known as Bucky balls), which can be used to contain atomic species inside a cage that separates them from the environment. We can store the quantum information in an electron or nuclear spin, and exchange it between the two. We can manipulate and characterize the spin states by electron paramagnetic resonance and also optically. By creating entanglement between several spins, it is possible to develop sensors that exceed the standard quantum limit. A core thrust of our research is to incorporate molecular materials in working devices for practical quantum technologies. There will be several projects with these nanomaterials, ranging from synthesis and microscopy to experimental implementation of candidate schemes for quantum computing. The research is highly interdisciplinary, and there is scope for a range of skills and interests from materials science and chemistry to experimental quantum physics. There may be possibilities for industrial support and for international travel and collaboration.

Also see homepages: Edward Laird Kyriakos Porfyrakis Jamie Warner

Nanoparticle toxicity characterization via atomic force microscopy
H. Bhaskaran

Nanoparticle toxicity is of high interest because of emerging concerns regarding their environmental impact. However, recent methods to manufacture nanoparticles using bio-inspired processing have been reasonably successful. The big question is: what is the difference between such bio-inspired processing routes and conventional routes. The DPhil student who will work on this project will pursue very advanced atomic force microscopy techniques in our laboratory to understand how surface texture at the nanoscale, as well charge contribute to theor toxicity. 

Our group is very well set-up to perform these measurements. We are now in possession of one of the most advanced atomic force microscopes with excellent collaborations with Asylum Research in Santa Barbara. Thus a DPhil student will be able to start on this project with plenty of informal as well as formal mentoring and support.

Your Profile:
Your profile will be one of a highly motivated undergraduate (evidenced by previous stints in Research laboratories), first class honors degree (or equivalent) earning undergraduate in Physics, Materials, Engineering or a closely related field with a deep desire to carry out independent experimental research. You must like working on hands-on laboratory experiments and have the desire to try out many novel ideas. Evidence (via references) of initiative and ability to work collaboratively would be a plus, as this is an experimental project.

Also see homepages: Harish Bhaskaran

Nanorobots for pick and place assembly of nano particles
H. Bhaskaran

We have an ambitious plan to deliver pick-and-place manufacturing at the nanoscale. To realize our ambitions, we are looking for a team member to pursue the doctorate on fundamental aspects of nanoscience, including the study of surface forces at the nanoscale and the ability to attract single nanoparticles reliably, and place them in a manner similar to automobile assembly - except this is at the nanoscale. This project is in close collaboration with Asylum Research of Santa Barbara USA, IBM Research - Zurich, Switzerland and the Microelectronics iNets with potential opportunities to travel to partner sites. 

The DPhil student working on this project will become an expert in advanced nanomanufacturing techniques, atomic force microscopy and nanoparticle assembly. All our projects allow for significant creative contributions and the right DPhil candidate will have the freedom to shape research directions.

Your Profile:
Your profile will be one of a highly motivated undergraduate (evidenced by previous stints in Research laboratories), first class honors degree (or equivalent) earning undergraduate in Physics, Materials, Engineering or a closely related field with a deep desire to carry out independent experimental research. You must like working on hands-on laboratory experiments and have the desire to try out many novel ideas. Evidence (via references) of initiative and ability to work collaboratively would be a plus, as this is an experimental project involving many collaborations.

Also see homepages: Harish Bhaskaran

Nanoscale patterning of graphene for electronic devices
J H Warner

One of the key challenges limiting 2D electronics is the ability to pattern features on the 10nm scale with high uniformity across a wafer. Field effect transistors comprised of graphene nanoribbons exhibit large on/off ratios only when their channel widths are sub-10nm. At this small size scale the structure of the edges plays a role in their transport properties. Developing methods to control the edge atomic structure is important and it will lead to uniform structures with tailored properties. This project aims to develop top-down lithographic approaches to achieving nanoscale structures in 2D sheets of graphene that are then incorporated into electronic devices. Graphene nanoribbon field effect transistors will be fabricated that are compatible with electron microscopy. Low-voltage aberration-corrected high resolution transmission electron microscopy will be used to characterize the atomic structure. The goal is to improve the performance of graphene nanoribbon field effect transistors by cleaning up the atomic disorder at the edges. Other methods to improve the atomic ordering at the edges such as Joule heating will be examined whilst inside the aberration-corrected HRTEM. The main focus of this project is to develop nanoscale patterning techniques that are scalable, rapid and provide uniformity across a large area.

Also see homepages: Jamie Warner

NanoSIMS analysis of nuclear materials
Professor Chris Grovenor

The NanoSIMS is a very high resolution instrument for performing chemical analysis of dilute species and with an exceptional sensitivity for light elements.  The NanoSIMS group have developed novel techniques for the study of trace element distributions in zirconium fuel cladding alloys exposed to corrosion in isotopically labelled water in order to explore the fundamental mechanisms of hydrogen pick up in service.   This project will design and carry out experiments on both hydrogen pickup and the effect of water chemistry (Li and B in particular) on corosion processes on real ex-reactor materials provided by our project partners in Westinghouse and Canadian Nuclear Laboratories.  There will be opportunities for visiting both laboratories and to work closely with leading international nuclear companies.

Also see homepages: Chris Grovenor

Next generation of solid-state lithium batteries electrolytes
Prof M. Pasta

Rechargeable lithium-ion batteries have revolutionized the portable electronics industry because of their high energy density and efficiency. They may also prove valuable for a variety of other applications, including electrification of the transport system and grid-scale stationary energy storage. However, they still suffer from several significant safety and reliability issues, many of which are related to the use of electrolytes dissolved in organic solvent. Solid-state electrolytes could resolve all of these problems. However, most candidate materials have much lower ionic conductivity compared to that of liquid electrolytes, which reduces the power density of the cell and limits their practical applications. 

Prussian Blue analogues have recently demonstrated remarkable electrochemical performance that is enabled by rapid movement of ions through their open-framework crystal structure. 

The overarching goal of this project is to identify PBAs materials that function as a stable, high-power solid electrolyte for lithium-ion batteries. PBA materials have many tunable properties that affect their electronic and structural characteristics. In this project, the student will explore the effect of these parameters on the structural, electronic and electrochemical properties of PBA. Collaborations (both internal, external) are expected.

 

Also see homepages: Mauro Pasta

NMR Crystallography: Exploring the use of J-couplings in Molecular Crystals
J Yates

Molecular crystals have a wide range of technological uses, from pharmaceuticals to electronic devices. Unfortunately, X-ray diffraction cannot always determine the structures of such materials. Solid-state NMR is an important technique for materials characterisation and could, in principle, be used for structure solution (so call 'NMR Crystallography'). However, there is no simple theory to link the observed NMR spectrum to the underlying atomic level structure (as Bragg's Law does for XRD).

In recent years we have developed computational techniques, based on quantum mechanics, to predict and interpret NMR spectra (see www.gipaw.net). Typically this has focused on the so-call NMR chemical shift, but, excitingly, it has recently become possible to both measure and compute the NMR J-coupling. J-coupling is an indirect interaction of the nuclear magnetic moments mediated by bonding electrons, and provides a direct measure of bond strength and a map of the connectivities of a system (hence its importance for crystallography).

The aim of this DPhil project is to study the nature of NMR J-coupling in molecular crystals - to interpret current experiments, understand the microscopic mechanisms, and guide the development of new experiments. The project is highly computational and will involve the use of large supercomputers, it may (optionally) include the development of new computational methods. The work will be carried out in close collaboration with experimental solid-state NMR studies performed in the group of Dr Steven Brown (University of Warwick).

Also see homepages: Jonathan Yates

Novel Photon Capture Methods for Multicrystalline Silicon
Prof PR Wilshaw and Dr S Bonilla

In order to move to a low-carbon future, and avoid the worst effects of anthropogenic climate change, continuing reductions in the cost of renewable energy are required. The semiconductor group at Oxford Materials, in collaboration with international research partners at Fraunhofer ISE in Germany and the University of New South Wales in Australia as well as industry partners, is working to reduce the cost of photovoltaic cells. Graduate students would work as part of a dedicated group of researchers on state-of-the-art techniques for improving the performance of crystalline silicon solar cells, which account for over 90% of all currently manufactured solar cells. Texturing of multicrystalline silicon wafers for solar cell production has been an ongoing concern for cell manufacturers. While anisotropic texturing of mono-crystalline silicon can reduce the weighted average reflection (WAR) of bare silicon to below 10%, most approaches on multicrystalline materials yield WAR’s in excess of 25%. Furthermore the traditional approach of using acidic etching solutions to preferentially attack defect sites is incompatible with new wafer sawing techniques. In this project the graduate student will develop novel texturing approaches for multicrystalline silicon. These techniques will be evaluated in collaboration with international research institutions and industrial partners including cell manufactures and wafer suppliers. If successful this technology will reduce the cost of solar electricity by realizing superior optical performance with a reduced cost of production.

Also see homepages: Peter Wilshaw

Novel routes to manufacturing layered inorganic nanomaterials
Dr. F. Dillon, Dr. R. Nicholls, Professor N. Grobert

Cabon nanotubes, have attracted increasingly more attention due to their outstanding properties in recent years. Concurrently, other 1D nanomaterials such as, inorganic nanowires and nanotubes of other layered materials, such as MoS2, WS2, BN, have been explored. Recently, new techniques for the precise structural control of WS2 nanomaterials were developed in house. Larger laboratory scale production, however, is still scarce and needs to be developed in order to make these novel nanomaterials viable for further characterisation, manipulation and application. This project will be focusing on the development of novel routes to inorganic 1D nanomaterials using chemical vapour deposition techniques. In this project the student will work closely with other members of the group and the samples produced by the student will be an integral part of a collaborative project with Dr Michael B Johnston (Department of Physics) and Dr Kylie Vincent (Department of Chemistry). It is envisaged to publish the findings in a peer reviewed journal and conference participation will be encouraged.

Also see homepages: Nicole Grobert Rebecca Nicholls

Persistent mode joints in high temperature superconducting materials
S.C. Speller / C.R.M. Grovenor

New designs of high field magnets are combining high temperature superconducting materials with modern closed cycle cooling systems to create systems that are cheaper to operate than conventional machines. Manufacturing these magnets will require processes for the fabrication of reproducible persistent mode joints between current leads and superconducting wires that can operate in significant background magnetic fields and also have the mechanical integrity to survive the thermal mismatches induced by warming and cooling operations. The student, working closely with our industrial partners Oxford Instruments, will use the new facilities in the Centre for Applied Superconductivity to design novel thermomechanical processes to form joints between commercial wires and leads, and measure their properties over a wide range of applied fields and temperatures. There will be opportunities for the student to spend time in the laboratories of Oxford Instruments, and to become an expert in the correlation of the microstructures formed by jointing processes and the superconducting performance of commercially-relevant devices.

Also see homepages: Chris Grovenor Susannah Speller

Phase separation in thin film polymers
Prof Hazel Assender

The project will examine phase separation processes and morphological changes in thin film polymers, comparing the processes and kinetics in thin film systems with those in the bulk.  Collaborations with other universities should allow novel polymer systems to be investigated.

Also see homepages: Hazel Assender

Probing the atomic scale structure and dynamics of energy materials
J Yates

The aim of this project is to develop and apply computational techniques to interpret solid-state NMR spectra of materials used in solid-oxide fuel cells and battery materials. Determining the local atomic structure and material function of such materials has proved challenging using convention (diffraction based) techniques, due to the presence of long-range disorder and ionic motion.

Solid-state NMR is a powerful probe of atomic scale structure and dynamics. However, there is no simple theory to link the observed NMR spectrum to the underlying atomic level structure (as Bragg's Law does for diffraction). In recent years we have developed computational techniques, based on quantum mechanics, to predict and interpret NMR spectra (see www.gipaw.net).

There are several possible routes for this project, depending on the student's interest - either focusing on applying existing techniques to novel problems, or developing new computational methodologies. There will be close collaboration with experimental NMR groups, both international and within the UK.

Also see homepages: Jonathan Yates

Putting the mechanics into quantum mechanics: creating superpositions of motion using vibrating carbon nanotubes
E A Laird / N Ares / GAD Briggs

The quantum mechanics of microscopic objects such as atoms and spins is well established. But what about larger objects? Can we verify true quantum behavior for these?

As a first step to answering this question, we plan to create and measure quantum superpositions of nanoscale mechanical devices. Although tiny by everyday standards, even the smallest fabricated device contains thousands of atoms. We will make use of suspended vibrating carbon nanotubes. These possess many attractive features for creating mechanical quantum superpositions, including low mass, large quantum level spacing, and comparatively large zero-point motion. Our goal is to carry out a foundational test of quantum mechanics – the Leggett-Garg test – that falsifies the hypothesis of classical behavior in this device. This project will focus on creating and probing so-called “macroscopically distinct” superpositions, such as a superposition of zero and ten phonons in the same device. These challenging experiments on tiny devices are the first step on a long road to discovering whether quantum mechanics applies to macroscopic objects.

Also see homepages: Andrew Briggs Edward Laird

Quantitative atomic resolution imaging
A Kirkland

Almost all structural information derived from High Resolution Electron Microscopy relies on qualitative matching of observed and calculated images. This project aims to investigate the fundamental reasons as to why the calculated and measured image contrast differs by significant amounts and to develop new quantitative approaches to image matching that can be applied to a range of structural problems.

Also see homepages: Angus Kirkland

Quantum confinement in oxide nanostructures
Professor Martin Castell

Crystalline oxides such as SrTiO3 have vast potential as a material to be integrated in the next generation of microelectronic devices. It has recently been discovered in Oxford that certain surface treatments of SrTiO3 produce atomic scale nanostructures by subtly changing the ratio of Ti to Sr in the surface region. The aim of this DPhil project is to investigate the quantum confinement of electrons in these nanostructures, similar to the particle in a box problem in elementary quantum mechanics. Atomic resolution scanning tunneling microscopy will be used to determine the size and distribution of the nanostructures, and spectroscopy techniques will show the degree of quantum confinement. For this research a new state of the art microscopy/spectroscopy facility is available.

Also see homepages: Martin Castell

Quantum interference in single-molecule devices
Dr J. A. Mol, Professor G. A. D. Briggs and Professor H. L. Anderson*

Quantum interference offers a rich resource which could be exploited in molecular devices. If there are multiple pathways for energy transport through a molecule, or if electrical transport is subject to resonances within a molecule, then these effects could be exploited for practical technologies. For example, it may be possible to make transistors with much lower power consumption than current silicon CMOS, and it may be possible to develop improvement of thermovoltaic materials for scavenging heat that would otherwise be wasted. Understanding such phenomena may also shed light on postulated quantum coherent processes in biology, ranging from photosynthesis to bird navigation.

The project will require nanofabrication of carbon-based devices into which individual molecules can be inserted. The current through the molecules will be measured with a view to discovering mechanisms of quantum interference. A major challenge will be to devise and fabricate geometries with additional gates to control the quantum interference. The project will involve nanofabrication, chemical attachment of the molecules, and electrical measurements over a range of temperatures and frequencies, with especial regard to discovering the conditions under which quantum coherence can be found. A successful outcome will be to find regimes in which quantum coherence gives enhanced device performance.

* Department of Chemistry

Also see homepages: Andrew Briggs Jan Mol

Quantum read-out of spin resonance in a silicon transistor
Dr J. A. Mol, and Professor G. A. D. Briggs

If quantum computers could be made using silicon materials, they would benefit from the vast investment that has been made in the purification of the materials and the nanofabrication of devices. Recent work in collaboration with Oxford has shown that the quantum coherence time of spin qubits can be more than three hours. The great challenges now are to learn how to control the interactions and measure the states of a small numbers of spins in silicon. This project will seek to detect electron spin resonance in a nanoscale silicon transistor through the resulting change in current.

The project will study electrically detected magnetic resonance (EDMR) in state-of-the-art silicon transistors. The size and geometry of these devices allows for the detection of spin states down to level of a single donor atom. The project will combine device fabrication and measurement with cavity-based electron and nuclear magnetic resonance. This will open the way to exploring phenomena usually associated with atomic physics for quantum information processing. The project will demand good knowledge of physics and/or electrical engineering as well as a deep understanding of semiconductor materials, and will benefit from new facilities currently being established at Oxford for experiments on quantum devices.

Also see homepages:

Quantum superposition in a vibrating carbon nanotube
Professor G. A. D. Briggs, Dr E. A. Laird and Dr N. Ares

There are two motives for extending the amount of ‘quantumness’ in our materials and devices. One is to develop technologies which exploit uniquely quantum phenomena, to perform tasks which are not feasible using classical physics alone. The other is to investigate ways in which classical realism can be ruled out in interpreting quantum measurements. A well-established test of ‘macrorealism’ is provided by the Leggett-Garg inequality (LGI), which enables you to tell whether or not a system is in one and only one state at any given time. We have demonstrated violations of the LGI in atomic scale systems, and the time is now ripe to stretch the limits of ‘macroscopicity’ which can be tested.

This project will test the LGI in different states of a vibrating single-walled carbon nanotube. Nanotubes will be mounted so that their vibrational frequency can be tuned electrically at frequencies of tens of gigahertz. They will have a high quality factor, so that their quantum states decay only slowly, typically over 10,000 or more oscillations, with large level spacing, so that they can be cooled to the quantum ground state in a dilution refrigerator. A pair of valley-spin qubits in the nanotube will provide means of excitation one quantum at a time, and also the means of measuring resulting states. A carefully designed experiment will make it possible to test whether the LGI is violated, and hence whether a macrorealistic interpretation of the experiment can be ruled out. This will be an important practical demonstration of how to increase size of systems that manifest fully quantum behaviour.

Also see homepages:

Radiation damage in superconducting materials
S.C. Speller / C.R.M. Grovenor

Superconducting magnet windings in particle accelerator applications are often subjected to high fluxes of energetic particles, and little is known about the effect on the superconducting properties of the lattice damage resulting from these interactions. Now that superconducting coils are being designed for possible future fusion power systems, it is particularly important to develop a better understanding of these damage mechanisms. This would be a CASE studentship in collaboration with a local company, Tokamak Energy, and with Oak Ridge National Laboratory in the USA and the University of Vienna. The project will use advanced electron microscopy techniques to identify the key damage mechanisms in a range of different superconducting tapes and wires exposed to high energy particles and to correlate these with direct superconducting property measurements.

Also see homepages: Chris Grovenor Susannah Speller

Recycling of Al alloys
K A Q O'Reilly

Reducing energy use is a major component of the UK’s policy for meeting its CO2 emission targets. Vehicle lightweighting, by replacing steel components with light alloy castings and wrought components, has been identified as one of the technologies with the greatest potential to contribute to this goal. Aluminium alloys are hence being used by the automotive and aerospace sectors. However, these industries are currently using primary grade aluminium, as recycled materials do not give adequate mechanical properties.  
A recent life cycle assessment for the Al industry showed that the production of 1kg of primary Al, when all the electricity generation and transmission losses were included, required 45kWh of energy and emitted 12kg CO2, whereas 1 kg of recycled Al required only 2.8kWh (5%) energy and emitted 0.6kg (5%) of CO2. Hence the use of recycled materials would considerably reduce the carbon footprint.
This project will investigate the ability of melt conditioning to improve the mechanical performance of recycled materials. Melt conditioning is defined as treatment of liquid metals by either chemical or physical means for the purpose of enhancing heterogeneous nucleation through manipulation of the chemical and physical nature of both intrinsic (naturally occurring) and extrinsic (externally added) nucleating particles prior to solidification processing. A prime aim of melt conditioning is to produce solidified metallic materials with fine and uniform microstructure, uniform composition and minimised cast defects and hence good mechanical properties.

Also see homepages: Keyna O'Reilly

Roll-to-roll manufacture of OTFT sensors
Prof Hazel Assender

We are seeking to develop sensor devices based on organic transistors on polymer substrates by roll-to-roll vacuum deposition using high-throughput molecular and polymer evaporation.   The project will be to explore options for manufacture of sensor devices, and an exploration of sensitivity and selectvity of the analytes by such devices.

Also see homepages: Hazel Assender

Sensing, characterisation and manipulation at the nanoscale using optical microcavities
Prof Jason Smith and Dr Aurelien Trichet

Optical sensing and spectroscopy are powerful tools for detecting and characterising nanoparticles at the single particle level. Pollutants and aerosols or microbiological organisms such as viruses have characteristic optical signatures based on their refractive index, size, and polarisability as well as spectral signatures that allow them to be identified and studied. This project will develop novel optical microcavities as means of confining light such that its interaction with nanoparticles is both strengthened and highly controlled. These microcavities show great potential for the trapping and manipulation of particles, and for particle identification using refractive index and spectroscopic methods. The project will involve fabrication of cavity devices and using them to perform some foundational experiments in this area. The student project is part of a larger effort within the group, in collaboration with Dr Claire Vallance in the Department of Chemistry. 

Also see homepages: Jason Smith Aurelien Trichet

Sensor Technology Based on Large Area Synthetic Graphene
Jamie Warner

Sensor technology, such as touch screen displays and pressure/strain sensors, will be developed using graphene. The graphene will be synthetic and of large area, produced using metal catalyst assisted chemical vapour deposition. Processing methods for transferring the graphene onto transparent flexible polymer substrates will be developed. This project aims at bringing graphene into application and will utilize recent advances within the group for producing outstanding synthetic graphene material. Optical and electron beam lithography will be used to pattern the graphene and metal electrodes for devices. Interfacing with computer hardware will be undertaken to achieve functioning sensor technology.

Also see homepages: Jamie Warner

Silicon quantum electronics
Dr J. A. Mol and Professor G. A. D. Briggs

Quantum information embodied in spins in silicon can be manipulated very precisely, and can persist for over three hours.  Quantum computers made from silicon materials would benefit from the great industrial development of silicon processing and nanofabrication. Much of previous research in silicon for quantum computing has used donor impurities in bulk crystals. The great challenges now are to learn how to measure the states and control the interactions of a small numbers of spins in silicon. This project will seek to develop control techniques that will be sufficiently precise to allow fault-tolerant error-correction in silicon devices with small numbers of spins. Scalable quantum technologies will need to meet and surpass certain accuracy thresholds to demonstrate quantum error correction. The goal of the project will be to exceed these thresholds using impurity and quantum dot spins in silicon devices. For this you will investigate magnetic resonance in both many-spin and single-spin regimes. You will need to have, or to acquire early in the project, good knowledge of physics, magnetic resonance, quantum information, and semiconductor materials.

Also see homepages: Andrew Briggs Jan Mol

Slip Band - Grain Boundary Interactions in Ti alloys
Prof A J Wilkinson

Over the last few years we have had good success using EBSD to map local stress distributions at the head of slip bands intersecting with grain boundaries and the work has received considerable interest. This project will extend the measurements by looking at how material alloying and mechanical parameters alter the response. In Ti oxygen content and Al alloying have profound effects on strength and alter slip planarity. This can alter the amount of plastic strain localised into a particular slip band and hence influence the magnitude of stress ‘hot spots’ that develop at grain boundaries. Similarly altering the mechanical loading conditions from quasi-static tension, to creep or cyclic ratcheting may also alter the strength of grain boundaries as barriers to slip transfer.

 

Also see homepages: Angus Wilkinson

Spectroscopy and device applications of monolayer semiconductors coupled to optical microcavities
Prof Jamie Warner, Prof Jason Smith

Monolayer semiconductor materials such as WS2 and MoSe2 display strong optical transitions that are attractive for nanoscale optoelectronic devices. These properties can be both enhanced and harnessed by coupling the materials to optical microcavities, opening possibilities for fast optical switches, ultra-low threshold lasers, and advanced quantum light sources. This project brings together the expertise of two leading research groups in 2D materials (Prof Jamie Warner) and in microcavity photonics (Prof Jason Smith). The project will build on some preliminary work which provides first demonstrations of basic phenomena, and will develop the experiments further to investigate ‘strong coupling’ (ie the creation of polaritons - part electronic excitation, part photon) and the switching of polariton states to realise ambient temperature devices.

Also see homepages: Jason Smith Jamie Warner

Spray forming of high entropy alloys
Professor Patrick Grant

High entropy alloys is a term applied to a new type of metallic alloy system that comprises near equi-atomic concentrations of at least three alloying elements, and frequently more. Since their discovery simultaneously in Oxford and Japan in 2004 a large number of alloys have been developed at small scale. A key and potentialy attractive aspect of these alloys is that despite their apparent compositional complexity, they may form extremely simple microstructures, including stable solid solutions. More recently, some alloys have been shown to offer exciting but sometimes puzzling mechanical properties. To advance these alloys and to understand their potential for commercial applications requires the manufacture of high quality alloys at larger scale, and the development of critical process-structure know-how. This project will make use of the range of leading spray forming and casting equiment available at Oxford for the manufacture of high temperature, complex composition alloys of up to 30 kg billets. The as-sprayed microstructure and its development in downstream processes will be carefully studied, and mechanical properties studied in collaboration with investigators in Oxford, China and the US.

Also see homepages: Patrick Grant

Stabilization of world record surface passivation for high efficiency silicon solar cells
Supervisors Prof PR Wilshaw and Dr S Bonilla

In order to move to a low-carbon future, and avoid the worst effects of anthropogenic climate change, continuing reductions in the cost of renewable energy are required. The semiconductor group at Oxford Materials, in collaboration with international research partners at Fraunhofer ISE in Germany and the University of New South Wales in Australia as well as industry partners, is working to reduce the cost of photovoltaic cells. Graduate students would work as part of a dedicated group of researchers on state-of-the-art techniques for improving the performance of crystalline silicon solar cells, which account for over 90% of all currently manufactured solar cells.

Efficiency in the most advanced silicon solar cells is limited by recombination of photo-excited electron-hole pairs at surfaces and interfaces. Future generations of industrial high efficiency solar cells will require cost effective techniques for producing semiconductor/dielectric interfaces with very low rates of recombination. The process of creating these low recombination interfaces is known as surface passivation and its development is critical to the next generation solar cells. Existing work in the semiconductor group has produced record breaking surface passivation using charge extrinsically added to dielectric coatings. The problem, however, is that the passivation produced is not stable over a period of years as required for solar cells in the field. This project aims to develop new techniques that will stabilise the charge in dielectrics to produce superior and industrially relevant passivation of silicon surfaces.

The student performing the work will be involved in cleanroom processing and dielectric characterisation using electronic and optical techniques. They will have the opportunity to apply the passivation techniques to the most advanced silicon solar cell structures developed by research institutions around the world.

Also see homepages: Peter Wilshaw

Strains Induced by Hydride Formation in Zirconium
Prof Angus J Wilkinson

In service temperature cycling of nuclear fuel cladding can lead to repeated sequences of precipitation and dissolution of hydrides in zirconium based alloys. During the transformation from hydrogen in solid solution to the hydride phase there is a considerable volume expansion. This project will explore the links between nucleation sites, hysteresis between temperatures for precipitation and dissolution, the stress field and local plasticity induced by the transformation strain and the precipitation morphology. The following techniques will be used: high resolution EBSD, digital image correlation of SEM images, in situ thermal cycling, finite element based-crystal plasticity simulations. This project will be carried out in close conjunction with Rolls Royce and other partner Universities within the HexMat flagship EPSRC programme (http://www3.imperial.ac.uk/hexmat).

Also see homepages: Angus Wilkinson

Structural anisotropy properties correlations in materials for electronics and photonics
A Kirkland / K Borisenko

Chalcogenide phase change memory materials (for example, Ge2Sb2Te5, GST) find applications as electronic memory storage materials. In these materials the phase change, and therefore information storage, can be initiated by laser or electric pulses. It has recently been suggested that by using polarised light to initiate the phase change it may be possible to control the  anisotropic structures. In GST materials this could add an extra parameter  to increase the fundamental storage density. In the project we will prepare new chalcogenide-based phase-change memory materials with dopants that are likely to induce anisotropic properties and study their atomic structures .  The project will also involve measurements of the optical and electric properties of the prepared materials and the building of computed models describing structure – property correlations. The project will involve electron micrsoscopy, computer modelling and studies at the Diamond Synchrotron.

Also see homepages: Angus Kirkland

Structural studies of Graphene and other 2D crystals with single atom sensitivity
Jamie Warner, Angus Kirkland

Graphene is a 2D crystal only one atom thick and is ideal for studying individual atoms by transmission electron microscopy. This project will focus on understanding fundamental crystal defects in graphene and other 2D crystals such as boron nitride, MoS2 and WS2. Mono-vacancies and the other non-6 member ring structures that exist in the unique 2D crystal. It will also investigate the grain boundary interface between two graphene domains with the aim of mapping out the unique atomic stitching that occurs. Graphene will be grown by chemical vapour deposition. This project will use Oxford's state-of-the-art aberration-corrected high resolution transmission electron microscope, equipped with a monochromator for the electron beam to give unprecedent spatial resolution at a low accelerating voltage of 80 kV. Advanced image analysis techniques, including exit-wave reconstruction, and comparison to image simulations will be utilized for a deeper understanding of the atomic structure.

Also see homepages: Angus Kirkland Jamie Warner

Studies of rapid phase-change and resistive memory materials for information storage
Professor A I Kirkland / Dr K Borisenko

Phase change memory materials based on chalcogenide alloys and resistive memory materials based on metal oxides are an important class of industrial materials, which find applications in electronic storage and rewritable memory. The operation of phase-change memory is based on fast and reversible phase transformation between amorphous and crystalline forms which have different properties. Similarly, resistive memory operates by transition between states that have different resistivities. Despite their wide commercial applications the exact mechanism describing fast phase transitions or resistance changes remains unclear. To understand the ways in which performance of memory devises using such materials can be improved, accurate structure properties correlations are required. The project will involve preparation of new phase change and resistive memory materials and investigation of their atomic structures using advanced diffraction and imaging techniques as well as theoretical simulations. The electric and optical properties of the materials will be also measured and correlated with their structures

Also see homepages: Angus Kirkland

Superconducting thin films for quantum devices
S.C. Speller / C.R.M. Grovenor

Many of the most exciting advances in quantum technologies rely on very high quality resonant circuits fabricated in superconducting materials. Simple Al or Nb films can be used, but many of the most impressive results have been achieved with nitride films as the superconducting material because they offer greater stability to atmospheric attack and oxidation and so are less lossy. Previous work on TiN films has shown that the stoichiometry uniformity, oxygen content, resistivity, texture and residual strain all have a significant impact on resonance performance, and that film uniformity over large areas will become an important issue in future more complex circuit designs. Although high quality VN and NbN thin films with excellent superconducting properties can be deposited, these materials have not been much tested for use in resonant circuits. The objective of this project is to explore a wider range of new superconducting compounds and alloys for low loss resonant structures. The student, working closely with our industrial partners Oxford Instruments, will use the new thin film growth and characterisation facilities in the Centre for Applied Superconductivity to deposit and measure the properties of nitride thin films, and to assist in the testing of resonator performance with the quantum technology groups in both Physics and Materials Departments.

Also see homepages: Chris Grovenor Susannah Speller

Surface structure characterisation of iron-based superconductors and topological insulators
Dr Susannah Speller/Professor Martin Castell

The unexpected discovery in 2008 of a new family of superconductors based on iron promises to lead to substantial progress in understanding the elusive mechanisms responsible for high-temperature superconductivity. However, worldwide efforts to understand the fundamental properties using a wide variety of experimental techniques have so far proved to be inconclusive and contradictory due to the lack of detailed understanding of the complex microstructures of even the best single crystal samples. This project involves using Scanning Tunnelling Microscopy (STM) to investigate the surface structure with atomic resolution in combination with High-Resolution Electron Backscatter Diffraction analysis for mapping local structural variations on the micron-scale.

Iron-based superconductors are only one of several novel quantum state materials of great interest in the scientific community. Another 'hot topic' are the so-called topological insulators, which exhibit bulk insulating properties with special conducting surface states, promising dissipation-less carrier transport at room temperature. There are a wide range of potential applications for these exciting new materials including dramatically faster, almost powerless computer chips. The experimental techniques developed in this project are ideally suited to studying the distribution of ferromagnetic additions needed to exploit the exciting properties of topological insulators in practical devices.

Also see homepages: Martin Castell

Synthesis of large area graphene sheets using chemical vapour deposition
J H Warner

The 2D crystalline nature of graphene makes it suitable for large area transparent conducting electrodes. Recent advances in chemical vapour deposition (CVD) methods now permit a route to making large area sheets. This project will focus on understanding the growth mechanisms behind CVD grown graphene and then developing approaches to improve the atomic structure and electronic properties. Insights into the structure will be gained using atomic-resolution imaging with low-voltage aberration-corrected high resolution transmission electron microscopy. Techniques to transfer the sheets to transparent substrates, such as glass or flexible polymers will be examined and the sheet resistance determined. Methods to incorporate dopants into the CVD growth process will be pursued with the aim of improving conductivity. Controlling the number of graphene layers grown by CVD will be investigated.

Also see homepages: Jamie Warner

Tailored nanocrystal catalysts
Professor Martin Castell

Currently, industrial catalyst nanoparticles used for pollution control and chemical processing are randomly dispersed on their supports with a large variety of sizes and shapes. Within this multi-billion pound industry the main research driver is to find ways of increasing the catalytic efficiency of the precious metals used such as Pt, Pd, and Rh, or increasingly alloys of various metals. One method is to increase the surface to volume ratio of the particles, and much effort has been directed towards that goal. Another method, proposed here, is to recognise that the crystal facets of the catalyst particles all have different chemical properties. This means that highly efficient catalysts can be created by synthesising particles with particularly large fractions of highly active crystal facets. One of the central aims of this project is to develop new processing routes to allow large-scale manufacture of shape and size selected metal and oxide nanoparticles with high catalytic efficiency. The project will also involve the synthesis of core-shell nanocatalysts. Characterisation of the catalyst particles will be carried mainly with scannning tunnelling microscopy.

Also see homepages: Martin Castell

The Effect of Microstructure on Strength and Fracture Resistance of Nuclear Graphite
James Marrow, David Nowell (Engineering)

The project is concerned with the role of significant defects, such as single or collections of large pores, on sub-critical and critical crack propagation in polygranular nuclear graphite, which is used as a moderator and structural component in the UK Advanced Gas Cooled Reactors, and also in some designs of Generation IV advanced high temperature reactors.

The aim is to experimentally validate a key aspect of the microstructure modelling of short crack propagation in nuclear graphite: the role of significant defects such as single or collections of large pores.  Advantage will be taken of new facilities in Oxford (high resolution X-ray computed tomography) and methods for in situ study of three-dimensional deformation and damage (e.g. digital volume correlation).  The work will be done using non-irradiated graphite, but the methodology developed will be suitable for active studies in due course.

The project's objectives are to observe the propagation of sub-critical cracks from significant defects in virgin graphite, test developed microstructure-sensitive models of sub-critical crack propagation, simulate the effect of the effects of microstructure on the statistics of strength and fracture resistance of virgin graphite and improve the modelling of sub-critical crack propagation in reactor components.

This project is in collaboration with EDF Energy Generation.

Also see homepages: James Marrow

The Role of Oxygen in Ti-alloys for Aerospace
P.A.J. Bagot / D.E.J Armstrong / M.P. Moody

Titanium-alloys are the dominant engineering material in modern aircraft frames, internal structures and gas-turbine engines due to their unsurpassed characteristics of excellent corrosion resistance and high specific strength. A current area of interest in these alloys is the role of oxygen, which strengthens but also cause embrittlement. The exact mechanism by which oxygen does this, along with how it varies in different alloys is not properly understood. In this project, carried out in close collaboration with Rolls-Royce plc, the advanced characterisation tool of Atom Probe Tomography (APT) will be utilized to study a range of commercial alloys with different introduced oxygen contents, aiming to explore where oxygen resides with the microstructure, whether at dislocations, grain boundaries or phase interfaces, and how this may change with heat treatments. Supporting Transmission/Scanning Electron Microscopy experiments and mechanical testing will also be carried out to properly link atomic-scale chemistries to engineering performance. A second theme will be exploring the structure of oxides and oxygen-rich layers formed at the surface of components exposed to working environments, along with developing and utilising unique reaction cell facilities within the Atom Probe Tomography group to carry out tightly controlled realistic exposures

Also see homepages: Paul Bagot

Three projects on the materials chemistry and electrochemistry of lithium-air, lithium-ion and sodium-ion batteries, and Li-ion solid electrolytes
Prof Peter G Bruce (Wolfson Chair in Materials, Departments of Materials and Chemistry)

1. The materials chemistry and electrochemistry of the lithium-air battery
Energy storage represents one of the major scientific challenges of our time. Pioneering work in Oxford in the 1980s led to the introduction of the lithium-ion battery and the subsequent portable electronics revolution (ipad, mobile phone). Storing electrons is key to a step change in electric vehicles and the storage of electricity from renewable sources.

Theoretically the Li-air battery can store more energy than any other device, as such it could revolutionise energy storage. The challenge is to understand the materials chemistry and electrochemistry of the Li-air battery and by advancing the science unlock the door leading to a practical device. The Li-air battery consists of a lithium metal negative electrode and a porous positive electrode, separated by an organic electrolyte. On discharge, at the positive electrode, O2 is reduced to O22- forming solid Li2O2, which is oxidised on subsequent charging. The project will involve understanding the electrochemistry of O2 reduction in Li+ containing organic electrolytes to form Li2O2 and its reversal on charging. While O2 reduction in aqueous media has been studied exhaustively for many decades, much less is known about the process in aprotic solvents.

The project will use a range of electrochemical, spectroscopic (Raman, FTIR, XPS, in situ mass spec.) and microscopic (AFM, TEM) methods to determine the mechanism of O2 reduction (presence and nature of intermediates e.g. superoxide,) and its kinetics. Our aim is not to build devices but to understand the underlying science. We seek highly qualified, ambitious, imaginative, hard-working and self-motivated candidates. Further details may be obtained by contacting simultaneously Dr Lee Johnson and me at: Lee lee.johnson@materials.ox.ac.uk and peter.bruce@materials.ox.ac.uk.

2. Polymer and ceramic Li-ion conducting electrolytes - the challenges
Replacing the flammable liquid electrolytes, used in current Li-ion batteries, with solid polymers or ceramics would transform safety and make the all-solid-state Li-ion battery a reality. There is worldwide interest in this topic. The project can focus on either polymer or ceramic Li-ion conducting solid electrolytes depending on the interests of the student. The work will involve the discovery, synthesis and understanding of solid polymer or ceramic electrolytes, but will also include the investigation of the interfaces between these electrolytes and typical solid anodes and cathodes used in Li-ion batteries. The interfaces are as significant a problem as is finding new electrolytes with high conductivity. A range of techniques to synthesise and characterise the solid electrolytes, including X-ray and neutron diffraction, electron microscopy, NMR, Raman and IR spectroscopy, X-ray tomography, as well as several electrochemical techniques will be employed. We seek highly qualified, ambitious, imaginative, hard-working and self-motivated candidates. Further details may be obtained by contacting peter.bruce@materials.ox.ac.uk.

3. The materials chemistry and electrochemistry of lithium and sodium-ion batteries
Lithium-ion batteries have revolutiosnised portable electronics and are now used in electric vehicles. However new generations are required for future applications in transport and storing electricity from renewable sources (wind, wave, solar). Such advances are vital to mitigating climate change. Sodium is more abundant than lithium and so attractive especially for applications on the electricity grid. Lithium and sodium ion batteries both consist of intercalation compounds as the negative and positive electrodes. The charge and discharge involves shuttling Li+ or Na+ ions between the two intercalation hosts (electrodes) across the electrolyte. In the case of Li-ion batteries currently the most common technology is still graphite (anode) and LiCoO2 (cathode). However, the development of increased energy storage in Li ion systems drives research to discover new materials. In the case of Na-ion batteries whilst the principles are analogous to that of the Li-ion battery, as yet there are no preferred candidates as electrodes, which provides excellent motivation for further work.

The project will involve synthesising and characterising a number of Na/Li containing transition metal oxides. This will utilise synthesis methods such as sol-gel, hydrothermal and solid state, characterisation will involve X-ray and Neutron diffraction, solid state NMR, XPS, FTIR, TEM and SEM. Additionally it is important to understand the processes at the interfaces between the intercalation oxides and the organic electrolyte. For such the interfacial studies FTIR, Raman, in situ mass spec and XPS will be the main techniques. We seek highly qualified, ambitious, imaginative, hard-working and self-motivated candidates. Further details may be obtained by contacting simultaneously Dr Nuria Tapia Ruiz and me at, nuria.tapiaruiz@materials.ox.ac.uk and peter.bruce@materials.ox.ac.uk.

 

Also see homepages: Peter Bruce

Three-Dimensional Fracture Mechanics
James Marrow, David Nowell (Engineering)

The fracture resistance of engineering materials is measured using standard test specimens; real cracks and engineering components are three-dimensional and more complex, so approximations and adjustments are needed to reliably assess their structural integrity. Over-conservatism, to safely account for the uncertainties in these adjustments, can have significant economic consequences.  There is also an increasing need to miniaturized test specimens, to monitor the degradation of structural material properties in fission and fusion energy generating power plants.

We are using 2D and 3D digital correlation image analysis, combined with X-ray computed tomography techniques (laboratory and synchrotron), to obtain precise, in-situ, measurements of the material displacements inside solid samples, such as the strain distribition at stress concentrations; damage development relaxes the elastic strain energy and increases strength for example.

You will investigate, by experiment and finite element modelling, the propagation of three-dimensional cracks, to develop novel test methods to study energy materials.

The project is suitable for graduates with an engineering, mathematical or physics background.

Also see homepages: James Marrow

Tissue engineering of scaffolds
J T Czernuszka

§ Tissue engineering is a rapidly expanding commercial and research area. To date, skin and articular cartilage have been tissue engineered and are available for clinical use. Other larger structures have been more difficult to produce. The major reason for this is the diffusion constraints imposed on the scaffold. We have developed a novel and unique method for producing three dimensional scaffolds from collagen, either by itself or as a composite with hydroxyapatite or other biopolymers. The technique involves rapid prototyping by solid freeform fabrication combined with CT/MRI data scanned directly from patients. Because we use SFF we can create a microvasculature within the scaffold ensuring that nutrients are kept supplied to cells deep within the structure. This is termed a 'platform technology' and the following examples show the breadth of tissues which can now be fabricated: bone, meniscal cartilage, heart valves, smooth muscle and arteries. We have a range of collaborations with leaders in their field both within the UK and abroad. There is scope for several projects within this general theme, depending on the interests and experience of the applicants.

Also see homepages: Jan Czernuszka

Tissue expanders
J T Czernuszka

§ Tissue expanders are widely used by plastic surgeons in reconstructive surgery. These are of the 'balloon' type which involves sequentially injecting fluid into the device to expand the overlying tissue. This tissue is then used elsewhere in the patient. We are developing an in situ anisotropic tissue expander for the treatment of severe cleft palates, syndactyly and tissue reconstruction following major burns. We are collaborating with plastic surgeons at the John Radcliffe Hospital and at the Radcliffe Infirmary and with colleagues at Georgia Tech in the US.

Also see homepages: Jan Czernuszka

Two-dimensional superconductors
F Giustino

During the past decade two-dimensional crystals such as graphene, boron nitride, and transition metal dichalcogenides have rapidly become the ultimate playground for exploring exotic physics in 2D. One potentially ground-breaking application of these novel materials is gate-tunable superconductivity, i.e. the possibility of inducing a superconducting state with a transition temperature controlled by a gate voltage in a transistor architecture. This possibility has recently been demonstrated in the case of MoS2 [Ye et al, Science 2012].

In our group we are interested in understanding and designing novel 2D superconductors using first-principles computational methods based on density-functional theory and many-body perturbation theory [Margine and Giustino, Phys. Rev. B 87, 024505 (2013)]. Recent work includes the study of possible superconducting phases of graphene [Margine and Giustino, Phys. Rev. B 90, 014518 (2014)], of hydrogenated graphene [Savini, Ferrari, Giustino, Phys. Rev. Lett. 105, 037002 (2010)], and more recently molybdenum disulphide monolayers.

In this project we will explore the potential of inducing superconductivity in a variety of transition metal dichalcogenide monolayers and their intercalation compounds. The prospective student is expected to possess a solid background in Solid State Physics, and a keen interest in theoretical modelling, linear algebra, and computer programming.

Also see homepages: Feliciano Giustino

Ultimate microscopy without lenses
A Kirkland

All Transmission Electron Microscope Images are resolution limited by the aberrations of the objective lens. This project aims to develop radical new approaches to overcoming these limitations by processing diffraction data thus avoiding the need for a good (or even any) lens. The approaches developed will form part of a multi University program and the Diamond Synchrotron investigating imaging and diffraction using a variety of radiation sources.

Also see homepages: Angus Kirkland

Ultra high resolution imaging of soft (biological) materials
A Kirkland

This project aims to extend many of the ultra high resolution imaging techniques that have been developed for imaging hard (radiation resistant) materials to soft materials including biological structures. This is an entirely new area and projects will be available in experimental, theoretical and computational areas or combinations of these. Part of this work may involve collaboration with the MRC laboratories in Oxford.

Also see homepages: Angus Kirkland

Ultra-sensitive molecular detection
Professor Martin Castell

The aim of this project is to develop a novel ultra-sensitive sensor for the detection of low concentrations of gases, especially concentrating on volatile organic compounds. The sensor design is based on our recently submitted 'percolation sensor' patent. It is made of a network of metal nanoparticles connected by conducting polymers and is optimised for high sensitivity and functionalised for selectivity. The student will be involved in a broad range of interdisciplinary activities from sensor design and construction to testing and evaluation.

Also see homepages: Martin Castell

Ultrafast Electron Microscopy
A Kirkland

Modern electron microscope can provide information at the atomic scale in the spatial dimemsion. The next generation of instruments will also provide temporal resolutions in the fs regime. This project will investigate solutions to providng temporal resoltuions from the ms to micro s timescale to bridge the gap between the limits imposed by current detectors and possible future pulsed electron sources.

Also see homepages: Angus Kirkland

Unconventional Computing using a Materials Science Approach
H. Bhaskaran

We want to achieve something unique - creating a computing system where data storage and processing are closely linked using a materials science approach. In this exciting and pioneering project we aim to create nanoscale devices using phase change materials, and investigate arithmetic computations on these devices - this is our attempt to mimic biological computing processes (albeit at a very early stage).

This is difficult to achieve, and so we need very, very bright and motivated colleagues. Doctoral students working on this project will have much scope to effect a large-scale impact in the future of computing. We also have several international academic collaborations for this project, and the student will have potential opportunities to travel to partner institutions in Germany and the USA.

The DPhil student working on this project will become an expert in phase change materials and memories as well as advanced measurement techniques. All our projects allow for significant creative contributions and the right DPhil candidate will have the freedom to shape research directions.

Your Profile:
Your profile will be one of a highly motivated undergraduate (evidenced by previous stints in Research laboratories), first class honors degree (or equivalent) earning undergraduate in Physics, Materials, Engineering or a closely related field with a deep desire to carry out independent experimental research. You must like working on hands-on laboratory experiments and have the desire to try out many novel ideas. Evidence (via references) of initiative and ability to work collaboratively would be a plus, as this is an experimental project.

Also see homepages: Harish Bhaskaran

Understanding High Temperature Small Scale Mechanical Performance of Materials for Nuclear Fusion
Dr D.E.J. Armstrong, Dr E. Tarleton, Professor A.J. Wilkinson,

Future nuclear fusion power systems rely on the development of materials which can withstand some of the most extreme engineering environments. These include temperatures up to 1500oC, high fluxes of high energy neutrons and effects of gaseous elements produced by transmutation and implantation from the plasmas. Due to efforts to minimise the production of nuclear waste by such reactors the elements which may be used in structural components is limited and in many cases there is a lack of understanding of the basic deformation processes occur in ether pure materials or alloys and importantly how these are effected by temperature, radiation damage and gas content.

This project will build upon the expertise in the MFFP and Micromechanics groups on high temperature mechanical testing at the micro and nano-scale. Facilities include two high temperature nanoindenters (-50oC to 950oC), high temperature microhardness (RT to 1500oC) and dedicated FIB-SEM and FEG-SEM with EBSD  as well as state of the art computer codes for strain gradient crystal plasticity finite element modelling and discrete dislocation plasticity modelling. Both nanoindentation, micro-compression and micro-bend experiments will be used to study plastic deformation and creep in a range of novel high temperature alloys (likely Fe, Cr and V based) with potential for use in future fusion reactors. HR-EBSD and AFM will be used to study deformation structures produced during testing and to inform strain gradient crystal plasticity finite element and discrete dislocation models. This will allow for a fuller understanding of the underlying physics of deformation in these materials both before and after irradiation or gas implantation.

Strong links will be made to activities within the Science and Technology of Fusion Energy (EPSRC Centre for Doctoral Training) and the Culham Centre for Fusion Energy.

Also see homepages: David Armstrong Edmund Tarleton

Understanding Radiation Enhanced Corrosion Mechanisms in Advanced Nuclear Materials
P. D. Edmondson / Prof. S.G. Roberts

Oxford Materials has established a major research effort in the study of materials for use in nuclear applications. This includes the radiation and corrosion effects of nuclear materials. Understanding these effects is extremely important in the design of new alloys in order to mitigate the degradation of materials during service.

This project, in collaboration with researchers at Sandia National Laboratory in the USA, will – for the first time – examine microstructural changes within advanced nuclear materials, from both radiation damage and corrosion. These process will be studied individually and holistically, as they occur. This analysis will be undertaken using the unique In-Situ Ion Irradiation Transmission Electron Microscope (I3TEM) facility at Sandia National Laboratory.

This project is available to students that satisfy both the academic requirements for Oxford University and security requirements for access to Sandia National Laboratory.

Any questions concerning this project can be addressed to Dr Phil Edmondson (philip.edmondson@materials.ox.ac.uk).

Also see homepages:

Understanding Radiation Induced Transmutation in Tungsten Alloys for Nuclear Fusion
Dr D.E.J. Armstrong, Dr P. Bagot

The development of viable nuclear fusion power plants relies on materials capable of withstanding the combined effects of high neutron irradiation and elevated temperatures in an extreme environment around the fusion plasma. Few materials proposed for plasma-facing components are capable of meeting these demands, with tungsten the leading candidate. During irradiation, transmutation effects will alter the composition of any materials, further complicating accurate predictions of lifetime assessment. Previous work has shown that binary W-Re and W-Ta alloys can form nanosized precipitates under irradiative exposures, which harden then ultimately embrittle the materials. However ternary W-Re-Ta and W-Re-Os alloys have been shown to behaviour quite differently under irradiation which raises important questions about the best route for mimicking transmutation pathways using pre-alloyed materials and fundamental questions regarding the mechanisms of precipitation formation in both irradiated and unirradiated alloys.

 

In this project, higher-order (both ternary and quaternary alloys from the W-Re-Os-Ta systems) alloys representing more accurate transmutation products will be exposed to ion-irradiation, then examined using a multi-technique approach of Atom Probe Tomography, TEM and Nanoindentation Measurements, aiming to link 3D chemical information at the atomic-scale to mechanical properties of these alloys. In this manner we hope to obtain a much deeper understanding of interactions between solute additions in these materials following irradiation, better understand the kinetics and thermodynamics of irradiation assisted precipitation and how this alters the mechanical behaviour.

Strong links will be made to activities within the Science and Technology of Fusion Energy (EPSRC Centre for Doctoral Training) and the Culham Centre for Fusion Energy

Also see homepages: David Armstrong

Understanding the mechanisms controlling stress corrosion cracking (SCC) through high-resolution characterization
Prof S Lozano-Perez

The operating mechanisms in environmental degradation of nuclear reactor materials are not fully understood. Several mechanisms have been proposed but none fully accounts for the experimental observations. A comprehensive set of samples has been tested in simulated reactor environment, revealing a clear correlation with operating temperature and alloy composition. This project will involve a detailed characterization by transmission electron microscopy and atom-probe tomography of selected samples, in order to provide with an atomistic understanding of the mechanisms involved in crack growth. You should have an interest for using and developing high-resolution experimental techniques.

The student will be part of a bigger group which works on the understanding of SCC in nuclear reactors, where collaborations (internal and external) are expected.

Please note that, currently, there is no studentship/funding associated to this project.

Also see homepages: Sergio Lozano-Perez

Understanding Zeolite Catalysts
Professor A I Kirkland

Zeolites are one of the worlds most important catalysts but their structures are still relatively poorly understood. This project which is co-sponsored by Johnson Matthey aims to understand how these catalysts evolve and degrade. The project will involve advanced electron microscopy under low dose conditions and possibly X-Ray synchrotron studies and computer modelling. There may be opportinities for direct placement with the Industrial partner.

Also see homepages: Angus Kirkland

Up-scaling graphene manufacturing to meet target device specifications
Dr. A.A. Koos, Professor N. Grobert

For graphene to become industrially viable und useful for technological applications large scale production of high-quality graphene must be developed. This project will investigate different routes to manufacturing highest grade graphene and the feasibility of up-scaling production. State of the art characterisation techniques will be employed for quality control, and close collaboration with internationally leading industries will form an integral part of the project.

Also see homepages: Nicole Grobert

Vacuum Deposited Organic Photovoltaics
Andrew Watt

In the last 3 years there has been a surge in the power conversion efficiency of organic photovoltaic devices to over 10% . This has been brought about by the development of new materials with improved electronic structure and molecular co-doping to create graded p-i-n structures. This project aims to build on this work and start from a first device operation principles to determine what the key metrics are for a good organic photovoltaic device. From here we will assess the conjugated molecules available and build devices using a new deposition tool that will be built as part of the project. Particular attention will be paid to using materials which are stable, low cost, environmentally friendly and amenable to large volume productio

Also see homepages: Andrew Watt

Vapour sensing of explosives, chemical agents, and drugs
Prof M R Castell

There is significant civil and military interest in the accurate detection of hazardous and illicit materials. Current methods for detecting explosives and narcotics include the olfactory sense of a trained sniffer dog and ion mobility spectrometry (IMS).

The aim of the work in this project is to develop vapour sensing technology that can be readily miniaturised and provide lightweight mobile or networked molecular detection of threats. A further requirement is that the sensor is cheap and does not require protracted training for the user. In Oxford we have been working on developing such sensors through research into the use of conducting polymer networks operating near the electrical percolation threshold, which we refer to as percolation sensors.

A DPhil (PhD) studentship is available to develop percolation sensors for the detection of explosives, chemical agents, and drugs. The student will be involved in a broad range of interdisciplinary activities including design, building, and testing of the sensor.  The student will have regular contact with the Dstl Explosives Detection Group, based near Sevenoaks in Kent and Porton Down in Wiltshire. Some extended visits to Dstl of a few weeks per year may also be required.

 

Also see homepages: Martin Castell

X-ray video imaging and machine learning based analysis to understand alloy solidification
Prof Patrick Grant / Dr Enzo Liotti

We have developed X-ray imaging equipment and experimental approaches to record real-time videos of the solidification of alloys with high temporal and spatial resolution. This technique is providing new information to help understand and resolve long-standing and important issues in solidification science, including the role of grain refiners, impurities, external fields and many other important practical parameters. The particular novelties developed in the group include: (i) the ability to apply a highly controlled and reproducible pulsed electromagnetic field during solidification to break-up dendrites and to mimic industrial processes; (ii) the use of new multi-element detector (with STFC) that allows the investigation of more complex composition, realistic alloys; and (iii) a range of image analysis techniques including state-of-the-art pattern recognition machine learning algorithms (with Engineering Science) that allow quantified data to be extracted from videos automatically. This project will exploit and further develop these capabilities to study and quantify the nucleation and growth behaviour of equiaxed grains during commercial casting practices. The work will involve X-ray imaging solidification experiments, microstructural analysis and computer programming for automated analysis of images and videos. The project will also require travel and stays of typically 5 days to X-ray synchrotron sources around the world, particularly the Diamond Light Source (UK), ESRF and Soleil (Grenoble and Paris, France) and the Swiss Light Source (Geneva, Switzerland).

Also see homepages: Patrick Grant

126 projects

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