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.

Open Admissions Field closing date: 20 August 2012

Important information for Applicants

SELECTION OF PROJECTS

When completing the Oxford application form, under the 'Supporting Materials' section entitled 'statement of purpose/research proposal', you must list in order of preference up to six 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.

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. For guidance on your status as a home, EU or overseas/international student, please see http://www.ox.ac.uk/students/international_students/doineedavisa/.

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: 18 November 2011, 20 January 2012 and 9 March 2012. Applications received after 9 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/postgraduate_courses/apply/apply_guide.html.

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 20th January 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 18 November 2011), although those who apply in the second field (application deadline 21 January 2011), will also be considered.

One or two EPSRC DTA 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 eligible for DTA awards. We do not assign Departmental DTA studentships to specific projects unless this is advertised in advance on our website. In a given year, some of the projects without ear-marked funding may be designated as ineligible for DTA funding. Usually most able and suitable applicants, as judged by our Graduate Admissions Criteria, are offered the awards; normally subject to a limitation of one DTA 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

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 only covered 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 2012 this difference is expected to be in the region of £36,000 over three years. Please see http://www.ox.ac.uk/admissions/postgraduate_courses/finance/index.html for a statement of the actual fees.

5 funded projects available at present.

***4 studentships in nuclear materials
( C.R.M. Grovenor / S. Lozano-Perez / P. Bagot / P. Edmondson)

***Micro-mechanical properties of advanced fission materials
( C.R.M. Grovenor /S.G. Roberts)

Atom Probe Tomography analysis of semiconductors and nanoelectronic devices
( M. P. Moody)

Materials for fission and fusion power
( S G Roberts / A J Wilkinson / P Bagot / P S Grant)

Quantum energy and nanostructures (theory and computation)
( S C Benjamin/ B W Lovett)

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

Other Projects - listed by supervisor, in alphabetical order

These projects do not have earmarked funding, but are available to students who win scholarships (including EPSRC DTA studentships) or have their own funding.

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

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

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

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

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

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

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

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

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

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

Professor Christopher R M Grovenor (chris.grovenor@materials.ox.ac.uk)

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

Dr Brendon W Lovett (brendon.lovett@materials.ox.ac.uk)

Quantum Information Processing

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

***4 studentships in nuclear materials

Dr Kanad Mallik (kanad.mallik@materials.ox.ac.uk)

Production of Semi-Insulating Silicon for High Frequency Devices

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

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

Dr John J L Morton (john.morton@materials.ox.ac.uk)

Dr John D Murphy (john.murphy@materials.ox.ac.uk)

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

Dr Keyna A Q O'Reilly (keyna.oreilly@materials.ox.ac.uk)

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

Prof Steven G Roberts (steve.roberts@materials.ox.ac.uk)

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

Dr Susannah C Speller (susannah.speller@materials.ox.ac.uk)

Processing of novel topological insulators in thin film form

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

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

Dr Andrew A R Watt (andrew.watt@materials.ox.ac.uk)

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

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

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

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

Other Projects - listed by primary research area

Characterisation of Materials

Modelling of Materials

Processing of Materials

Properties of Materials

Quantum Information Processing

(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'.

***4 studentships in nuclear materials
C.R.M. Grovenor / S. Lozano-Perez / P. Bagot / P. Edmondson

The Oxford Materials Department has established a major research effort in nuclear materials with funding from the Engineering and Physical Sciences Research Council and a number of global industrial partners. These new studentships are all externally funded and will offer the successful candidates the opportunity to join a very active team of 4 academic staff, 7 postdoctoral researchers and more than 20 students working on different aspects of materials design and materials degradation mechanisms critical to the nuclear industry, and to work closely with the funding companies.

***Studentships 1 and 2. Atomic scale mechanisms of hydrogen pick up in nuclear fuel cladding
C.R.M. Grovenor/S. Lozano-Perez/P. Bagot/B. Comstock (Westinghouse)

These 2 studentships are part of a large international project on the mechanisms of hydrogen pick up in zirconium fuel cladding alloys, involving researchers and industrial partners in the USA, France, Sweden and the UK. The detrimental impact of hydrogen on the performance of nuclear fuel is a serious issue for the efficient use of nuclear fuel in high burn-up applications. Understanding the mechanism of hydrogen pickup will provide a scientific basis for designing improved alloys. Working on the same samples, the first studentship will concentrate on chemical analysis at the atom scale by state-of-the-art Atom Probe Tomography, and the second will work on transmission electron microscopy and high resolution SIMS analysis. There will also be opportunities for undertaking experiments with the project partners, and spending time in their laboratories.

*Studentship 3. Stability of Bubble Lattices in irradiated materials
C.R.M. Grovenor /S. Lozano-Perez/P. Edmondson

During the irradiation of nuclear reactor components in service, small voids or bubbles can be created that degrade the mechanical properties. However, under certain conditions these bubbles can form stable lattices that are much less damaging to the macroscopic properties, and can allow the materials to have a much longer service life. This project will use transmission electron microscopy and ion irradiation techniques to define in a range of nuclear alloys the dose, flux and temperature conditions under which stable bubble lattices can be developed using implanted ions to mimic neutron irradiation.

This project is only available to a citizen of the United Kingdom.

***Studentship 4. Atom Probe Tomography studies of longterm ageing of nuclear pressure vessel steels
C.R.M. Grovenor /P. Bagot/ K. Wilford (Rolls Royce)

The Materials Department has a longstanding research partnership with Rolls Royce on the atomic scale changes of microstructure that occur in nuclear steels during thermal ageing which is intended to provide mechanistic understanding of similar changes during neutron irradiation. These microstructural changes can strongly influence the mechanical properties of the steels and have implications on the service life of nuclear components. This project will use state-of-the-art atom probe tomography techniques to study the precipitation processes in a unique set of nuclear steels thermally aged for more than 10 years, and there will be opportunity during the project for strong interaction with the sponsoring company.

These 3.5 year studentships will provide full fees and maintenance for a citizen of the UK or EU (the stipend is expected to be £15,500 per year, tax free). 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 2012 this difference is expected to be in the region of £40,000 over three years. Please see http://www.ox.ac.uk/admissions/postgraduate_courses /finance/index.html for a statement of the actual fees.

Any questions concerning the project can be addressed to Professor Chris Grovenor (chris.grovenor@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: Paul Bagot Chris Grovenor Sergio Lozano-Perez

***Micro-mechanical properties of advanced fission materials
C.R.M. Grovenor /S.G. Roberts

The Oxford Materials Department is expanding a major research effort in nuclear materials with funding from the Engineering and Physical Sciences Research Council and our industrial partners. The appointee to this new studentship will join a very active team of 4 academic staff, 6 postdoctoral researchers and 15 students working on different aspects of materials design and critical degradation mechanisms in the nuclear industry.

One of the key challenges in the study of existing and new materials for application in nuclear reactors is to undertake experiments on damage mechanisms at the scale at which they operate. This project will use and develop further novel methods which allow direct mechanical testing of microstructural features - e.g. grain boundaries, precipitates - at the micron-scale. The Oxford group will shortly be commissioning unique new apparatus to extend micromechanical testing up to 750°C (appropriate for materials for generation IV reactors). Two key areas of interest are the micro-mechanisms of delayed hydride cracking in zirconium alloys, and the strength of embrittled grain boundaries in structural alloys. The aim of the project will be to contribute experimental data to the development of new models for materials behaviour under the extreme conditions expected in new reactor designs.

This 3.5 year studentship is funded by an EPSRC project grants and will provide full fees and maintenance for a citizen of the UK or EU (the stipend is expected to be £15,500 per year, tax free). 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 2011 this difference is expected to be in the region of £33,000 over three years. Please see http://www.ox.ac.uk/admissions/postgraduate_courses /finance/index.html for a statement of the actual fees.

Any questions concerning the project can be addressed to Professor Steve Roberts (steve.roberts@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: Chris Grovenor Steve Roberts

Atom Probe Tomography analysis of semiconductors and nanoelectronic devices
M. P. Moody

Atom probe tomography (APT) is a microscopy technique capable of generating large 3D atom-by-atom images of a material, in which the chemical identity of every atom is characterised with very high accuracy. Hence, APT provides a powerful means to investigate the distribution of dopants that have been ion-implanted into semiconductor systems. In this project APT will be used to characterise the depth profile of implanted dopants, also undertaking a precise evaluation of clustering, segregation to defects in the silicon crystal and segregation to interfaces. APT can characterise the influence of fabrication processing conditions on the quality of the implantation and in this project a systematic mapping of the parameter space relevant to the fabrication requirements. APT may also be utilised in this study for the atomic-scale characterisation of nanoelectronic devices. This project offers an interesting blend of experimental and analytical challenges.

This project is supported from the Department's EPSRC Doctoral Training Account (DTA). The 3.5 year studentship provides full fees at the Home/EU rate and subject to eligibility (see below) will pay a stipend of at least £13,590 per year in the first year and at least this amount in subsequent years (pro-rata for the final six months).

Under the EPSRC rules Home (UK) students are eligible for full funding from a DTA studentship, as are EU students who have spent the previous three years (or more) in the UK undertaking undergraduate study.

For a small number of students each year the EPSRC's DTA studentship rules also give the University the flexibility to fully fund an EU student who does not meet the above criterion, but in most cases we are permitted only to fund the fees for an EU student. For such fees-only DTA studentships the student must fund minimum living costs of approximately £12,900 per year from their own resources/sponsorship.

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 20 August 2012. Further information concerning the project can be sought by e-mailing michael.moody@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 can be found at http://www.ox.ac.uk/admissions/postgraduate_courses/index.html.

Also see homepages: Michael Moody

Materials for fission and fusion power
S G Roberts / A J Wilkinson / P Bagot / P S Grant

Do you want to help to solve the future energy crisis? Are you interested in doing novel and exciting experimental work? Would you like opportunities for international collaborations and travel?

Fusion reactors potentially offer a complete solution to the problem of future energy supply, and are environmentally friendly: they emit no greenhouse gases, and so would not contribute to global warming. The recent success of the JET project at Culham in the south of Oxfordshire, which proved that plasma could be heated and controlled to produce fusion, has demonstrated the feasibility of the concept. The next step is to construct a prototype reactor (ITER) which is now the focus of a major international project. This will be followed by a prototype commercial reactor (DEMO).

So far relatively little demand has been made on the properties of the materials used for JET and other prototype reactors, since they had only to contain an operating plasma for very short times. For actual fusion power plants, materials issues will be crucial to success.

In the closer future, advanced fission reactors will be needed to meet some at least of the world energy demand, as fossil stocks dwindle and as their use become less environmentally acceptable. Materials degradation by radiation damage is a serious issue in current-generation reactors, and the new “generation IV” reactors currently being proposed will place even heavier demands on materials.

The materials needed will operate at temperatures of 600ºC or more, will need to withstand stresses up to 300MPa, and will accumulate over their lifetime radiation damage from fast neutrons amounting to ~100 displacements per atom. In fusion reactors, an additional problem will arise due to the high levels of helium and hydrogen produced in transmutation reactions. It is essential that any material used maintains adequate strength and toughness, while suffering minimal dimensional change through swelling and creep. These are very demanding requirements, which cannot be met by conventional structural materials. It will be necessary to develop and evaluate new materials.

Ion irradiation is currently the only non-activating method of mimicking the fast neutron damage produced in nuclear fission and fusion reactors (with or without co-implantation with He or H, to mimic the effects of fusion by-products). Implanted layers are ~2-3 microns deep or less. We have developed micromechanical test methods, using ion beam machining to make specimens only a few microns in size, for determination of the elastic, plastic and fracture properties of candidate materials. This is linked with parallel electron microscopy and atom-probe microscopy studies of the development and nature of the radiation damage, and of the interactions between radiation damage and mobile dislocations which give rise to hardening and embrittlement.The experimental work is closely linked to the development and verification of computer models of radiation defects and their interactions.

A new large research project in this area, an EPSRC programme grant centred at Oxford University, started in early 2010. It involves UK and European partners (especially Liverpool University, CCFE Culham laboratory, the Commissariat à l'Énergie Atomique (CEA), and Rolls Royce). It aims at providing a thorough understanding of the mechanical properties and irradiation response of materials with potential for fusion and advanced fission reactor applications, including low-activation ferritic-martensitic steels, oxide-dispersion strengthened steels, model Fe-Cr alloys and tungsten alloys.

Individual research student projects started in 2009, 2010 and 2011 in the areas of:

Tungsten-based alloys,
Radiation hardening and embrittlement,
Grain boundary irradation embrittlement,
Grain boundary stress-corrosion cracking,
Processing & properties of Oxide Dispersion Strengthened alloys

Further projects will be available, to start October 2012. Applications for studentships in these areas from well-qualified applicants of all nationalities are welcome, but the note that available funding covers fees and stipend of UK and EU nationals only.

Also see homepages: Paul Bagot Patrick Grant Steve Roberts Angus Wilkinson

Quantum energy and nanostructures (theory and computation)
S C Benjamin/ B W Lovett

A fully funded studentship is available with a team based at the University of Oxford, working to better understand energy transfer at the quantum level. The team, who are based in Oxford's Materials and Physics Departments, are collaborating with Heriot-Watt University in Edinburgh. We are studying various nanostructures but with particular interest in natural light harvesting systems (photosynthetic complexes).

We are interested in recruiting a student who has a physics undergraduate degree, or at least a degree with a strong physics component. The work will involve opportunities for both analytic and numerical calculations. There are already a number of team members focusing on analytic techniques, therefore applications from those with strong skills in numerical computation are particularly encouraged in order to complement this existing expertise.

The studentship is available immediately, or for any start date before October 2012. The eligibility extends to those of British or EU nationality, and will support three years of research and both University fees and maintenance costs (food, accommodation etc) will be paid for by the grant. The stipend is expected to be £13,590 per year.

To apply, or to request further information, email simon.benjamin@materials.ox.ac.uk. Applications should include a full CV and the names of three referees (it is not necessary for the referees to provide references at the initial application stage).

Also see homepages: Simon Benjamin

(return to list of funded project titles)

Other Projects - full details, listed by title

85 projects

A new approach for 3D Field Ion Microscopy
M. P. Moody

It is an exciting period for field ion microscopy (FIM) and atom probe tomography (APT) research. APT has risen to prominence recently because of its capacity to generate large 3D atomistic images of a specimen, in which the chemical identity of every atom is characterised with very high accuracy. However, limitations remain which are now encouraging some researchers to revisit its predecessor, field ion microscopy. FIM provides a highly resolved 2D image of the surface of the specimen with limited contrast between different types of atoms, depending on the analysed system. Significantly, unlike APT, FIM can image individual sites on the atomic lattice, and hence can identify the presence of vacant sites, dislocations and radiation induced damage to the crystal. The goal of this project is to extend these capabilities into three dimensions and to develop a new tomographic approach for 3D FIM. The student will undertake both FIM and complementary APT experiments on a range of materials, including: semiconductors, pure metals and steels. A key focus of the work will be the development and optimization of a tomographic reconstruction protocol to generate accurate 3D FIM images, and further to adapt analysis tools to characterise the nature of the data. Any questions concerning the project can be addressed to Dr Michael Moody (michael.moody@materials.ox.ac.uk).

Also see homepages: Michael Moody

Applications of aberration-corrected high resolution electron microscopy
A Kirkland

The department has installed one of the world’s only electron microscopes with aberration correctors in both the condenser (probe-forming) and objective (image forming) lenses. 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

Atomic Resolution Imaging of Defects and Grain Boundaries in Graphene
Jamie Warner, Angus Kirkland

Graphene is a 2D crystal only one atom thick and is ideal for studying individual carbon atoms using transmission electron microscopy. This project will focus on understanding fundamental crystal defects in graphene, such as edge dislocations (both glide and shuffle), 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, such as 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

Atomic structure and secondary electron emission
M R 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.

Also see homepages: Martin Castell

Atomic-scale Characterization of Catalytic Alloys
P Bagot / C Grovenor

Many industrial processes and chemical reactions rely heavily on the use of active metals as catalysts. For example, the key ingredients of automobile exhausts and fuel-cells are expensive metals including Pt, Rh, Ru and Pd. Maximising the efficiency of these is crucial for cost-effective catalysts. However a proper understanding how different metals behave in reactive environments has yet to be achieved; the surface composition of alloy catalysts can alter markedly from the as-prepared state under high temperatures/pressures. This project will use Atom Probe Tomography (APT), a unique facility in the UK, to investigate structural and chemical changes at the atomic scale on the surfaces of a range of alloys using a fully integrated reaction cell. The student will become an expert user of these advanced facilities, and be a member of the Oxford Catalysis Network.

Also see homepages: Paul Bagot Chris Grovenor

Atomistic modelling of semiconductor/polymer interfaces for excitonic solar cells
F Giustino

Hybrid excitonic solar cells based on blends of semiconductor nanocrystals and polymers have emerged as a potential alternative to dye-sensitized and all-organic solar cells. In hybrid solar cells the polymer enables the deposition of the active layer onto flexible substrates, and the semiconductor offers high carrier mobilities. During the past five years hybrid solar cells based on ZnO and the polymer poly(3-hexylthiophene) have received considerable attention, and solar cells using ZnO quantum dots or nanowires have successfully been demonstrated. The power conversion efficiencies of these devices, however, have not exceeded 2% due to low short-circuit currents and open-circuit voltages. In this DPhil project we want to clarify, using first-principles computational modelling, the atomic-scale mechanisms underlying the operation of semiconductor/polymer excitonic cells. Particular emphasis will be given to the alignment of the quantum-mechanical energy levels at the photovoltaic interface and to the generation of charge carriers. Computational techniques include hybrid-functional approaches and many-body perturbation theory methods. This DPhil project will involve the extensive use of high-performance parallel computers. Interactions with experimental groups in Oxford are anticipated.

Also see homepages: Feliciano Giustino

Biomimetic Energy Storage Devices
Dr Andrew Watt

Melanins are macromolecules found throughout the biosphere. Eumelanin is found in skin pigment and act as a photoprotectant and has been implicated in the development of deadly malignant melanoma. This project will seek to understand the optoelectronic properties of melanin using materials science techniques and fabricate supercapacitor structures using squid ink courtesy of the Japanese fishing industry. The project will involve, fabrication of melanin composite films, fabrication of supercapacitor devices, measurement of impedance and electrochemical properties and some physicochemical characterization eg XRD, SEM, XPS, TEM.

Also see homepages: Andrew Watt

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 as test materials by combing TEM and STM studies together with advanced image simulation. The project will form part of a major collaboration between Oxford and Northwestern University in Chicago with extensive opportunities for travel between the two.

Also see homepages: Angus Kirkland

Control of microstructure by grain multiplication
P. Grant

This project concerns the control of nucleation and subsequent microstructural evolution during solidification by intrinsic grain multiplication using external physical means such as acoustic/shock waves and pulsed magnetic fields. Fragments from broken dendrites are well-known to multiply the number of final grains in a casting, and so provide grain refinement and attendant improvements in quality and performance. The central idea of this project is to enhance dramatically this effect by disrupting continuously the thermal conditions in the melt and at growing solid/liquid interface, without any melt contamination. While various external field approaches have been developed, there remains some uncertainty in the mechanism of dendrite fragmentation, and this project will study both the underlying physics of grain multiplication as well as a new approach for its enhancement.

Also see homepages: Patrick Grant

Controlling the edge structure of graphene
J H Warner

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 as it will lead to uniform structures with tailored properties. This project aims to fine-tune the atomic structure of graphene nanoribbons using electron beam irradiation. Low-voltage aberration-corrected high resolution transmission electron microscopy will be used to characterize the atomic structure. Graphene nanoribbon field effect transistors will be fabricated that are compatible with electron microscopy. The small probe size in scanning transmission electron microscopy will be used to interact with atoms at the edges of the ribbons to provide greater control over the sputtering process. 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.

Also see homepages: Jamie Warner

Defect engineering to increase the efficiency of multi-crystalline silicon solar cells
Dr P.R. Wilshaw, Dr J.D. Murphy

Silicon solar cells account for over 80% of the solar cell market and this market is consistently growing at up to 40% per annum. Most of the silicon used for solar cells comes in the form of multi-crystalline wafers sliced from ingots of cast silicon. This material contains relatively high concentrations of metallic impurities, dislocations and grain boundaries, all of which enhance electron-hole recombination and hence reduce solar cell efficiency. This project aims to develop a range of novel ideas originating from the Semiconductor Group in Oxford. Ideas to be developed include the use of low temperature processes to clean-up the material ("gettering") and removing defects from the material in other novel ways. The research will rely on a wide range of experimental techniques, including basic electrical characterisation (IV, CV etc), electron beam induced current (EBIC), deep-level transient spectroscopy (DLTS), quasi-steady-state photoconductance decay (QSS-PCD), cathodoluminescence (CL) and transmission electron microscopy (TEM). The research will be performed in lose collaboration with leading suppliers of silicon to the photovoltaic industry.

Also see homepages: John Murphy Peter Wilshaw

Deposition of organic an inorganic layers on polymer substrates by roll-to-roll coating in vacuum
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 applications

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. This project will be within an already running EPSRC 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 Crack-Microstructure Interactions
Dr. A.J. Wilkinson

This project will continue to develop and apply computer simulation methods based on using dislocation dipoles to represent cracks and the associated localised plastic flow fields. An array of edge dislocation can represent the mode I opening (Burgers vector normal to the crack) and mode II shearing (Burgers vector along the crack). Previous work within the group began simulating multiply deflected and branched crack paths that are typical in IGSCC and lead to extensive crack-crack interactions and complicated variations in the local driving force for crack advancement (K). This project will aim to incorporate the effects of pre-existing residual stress variations on the crack propagation so as to simulate the technologically important cold work effects on micro-structurally short cracks.

Also see homepages: Angus Wilkinson

Electrical conductivity through 2D polymer networks
M R Castell

In this project the electrical transport properties of conducting polymer networks are investigated. The polymers are connected via metal nanoparticle nodes. The long term aim is to use these networks to act as highly sensitive gas sensors.

Also see homepages: Martin Castell

Electronic and optical properties of quantum-dot sensitizers for nanostructured solar cells
F Giustino

The solid-state semiconductor-sensitized solar cell is an evolution of the concepts of dye-sensitized solar cells and hybrid nanocrystal/polymer solar cells, whereby the molecular sensitizers are replaced by semiconductor quantum dots and the liquid electrolyte is replaced by a solid-state hole-transporter. These new solar cells are very promising because the semiconductor sensitizer can be obtained by inexpensive colloidal synthesis and the harvesting of sunlight can be tuned via quantum size effects by changing the size of the quantum dots. As this research field is very young, there exists a large number of semiconductor nanoparticles which could act potentially as quantum-dot sensitizers. The goal of this DPhil project is to investigate, using first-principles computational modelling, the electronic and optical properties of the most promising sensitizers, in order to identify candidate materials for high-efficiency solar cells. Computational techniques include highly accurate many-body perturbation theory methods such as the GW and the Bethe-Salpeter approach. Our group has a strong background in these computational methodologies and is currently developing high-performance algorithms for GW/BSE calculations. This DPhil project will involve the extensive use of high-performance parallel computers. Interactions with experimental groups both in Oxford and overseas are anticipated. [http://dx.doi.org/10.1002/adfm.201101103]

Also see homepages: Feliciano Giustino

Endohedral metallofullerenes for nanotechnological applications
K Porfyrakis / G A D Briggs

Fullerenes are fascinating carbon-based materials. Their most interesting feature is that due to their cage-like structure they can trap atom(s) inside their empty "shell". This project explores the synthesis and chemical functionalization of endohedral metallofullerenes: Mn@Cm (where n=1-3 and m ≥ 60).
We shall synthesise novel endohedral metallofullerenes using a new arc-discharge facility. We shall customise the fullerene molecular structure in order to tune their properties, such as their HOMO-LUMO gap. We shall develop methods for the covalent functionalization of endohedral metallofullerenes. We shall investigate the effect of rigid or flexible functional groups on the electronic properties of the endohedral species. We shall focus on malonate and pyrrolidine adducts initially, but other schemes will also be considered. Endohedral metallofullerenes and their derivatives will be purified by high-performance liquid chromatography (HPLC) and will be characterized by various spectroscopic techniques available to us, including mass spectrometry, UV-Vis-NIR and FTIR spectroscopies and other analytical tools.
These nanomaterials are of interest for quantum information processing, but are also attractive for opto-electronics and photovoltaic applications.

Also see homepages: Andrew Briggs Kyriakos Porfyrakis

Engineering excitons in semiconductor nanocrystals
Dr Jason Smith and Dr Andrew Watt

The ability to grow heterostructured semiconductor nanocrystals using wet chemical techniques opens up a plethora of new possibilities for engineering their optical and electrical properties. For instance (i) in type II heterostructures, the electron and hole that form the ‘exciton’ are separated spatially, so that optical gain can be generated; and (ii) alloyed structures have recently been grown in which luminescence blinking is absent – a discovery that may hold the key to developing nanocrystal-based LEDs, sensors, and even quantum optical devices. The aim of this project will be to investigate the excitonic behaviour of heterostructured and alloyed nanocrystals. In particular, low temperature spectroscopy of single nanocrystals will be used to gain information free from inhomogeneous and thermal broadening. Experimental results will be compared with theory developed in-house. Applicants interested in the synthesis of alloyed and heterostructured nanocrystals will also be considered.

Also see homepages: Jason Smith Andrew Watt

Excitonic solar cells
F Giustino

The ability to manufacture low-cost and high-efficiency solar cells is a strategic asset to meet the increasing global energy demand. In view of conjugating cost-effective materials processing with adequate energy conversion efficiency, significant efforts are currently being devoted to developing excitonic solar cells, including dye-sensitized solar cells and hybrid organic/inorganic solar cells. In such devices the interface between the semiconductor nanocrystals and the dye or polymer plays a crucial role in the separation of the excitons into electrons and holes, and influences both the energy-conversion efficiency and the open-circuit voltage of the solar cell. Despite the key role of the photovoltaic interface in excitonic solar cells, its morphology at the nanoscale is not well understood. A detailed modelling of the interface at the atomistic level would represent the first step towards a rational approach to device optimization. The aim of this DPhil project is to investigate the electronic and optical properties of these interfaces using atomic-scale quantum-mechanical simulations. We will first construct atomistic computer models of the interfaces between semiconductors and dyes or polymers, and then we will investigate their electronic and optical properties, including the ideal open circuit voltage and light absorption, using advanced electronic-structure techniques based on density-functional theory. The project will involve the extensive use of parallel high-performance computers.

Also see homepages: Feliciano Giustino

Fabrication and microstructural characterisation of novel iron-calchogenide superconductors
S.C. Speller / C.R.M Grovenor

In 2008 an entirely new class of high temperature superconducting compounds containing iron was discovered, and in the subsequent few months a huge number of different iron-based superconducting phases were synthesised. This project will focus on bulk samples and thin films of the simplest of these compounds based on FeSe. Up to 50% doping of Te on the Se site is known to significantly increase the critical temperature of these compounds, but there is considerable variation in the properties of samples made by different groups, and a lack of understanding of the detailed phase stability and chemistry in this system. Our aim is to use sophisticated microanalysis techniques (SEM/FIB/TEM) to determine the local phase chemistry in bulk and thin film Fe(Se,Te) samples fabricated in-house and single crystals grown by collaborators elsewhere, to develop a better understanding of the unusual magnetic and superconducting phenomena observed in these materials, and to enable the fabrication of higher quality samples by optimising processing strategies and chemical doping.

Also see homepages: Chris Grovenor

Fundamentals of cyclic deformation and fatigue crack initiation
A J Wilkinson / S G Roberts / F P E Dunne (Eng. Sci.)

Understanding of the basic nature of fatigue crack initiation and growth in metals has long been a problem. The SEM based techniques of ECCI and EBSD allow detailed study of the interaction of dislocation patterning and crack initiation and growth; data can be gathered easily from a large specimen volume throughout the whole fatigue life. The work will be on pure Cu and Cu-Al, or Cu-Zn alloys. The aim is to study how variations in, grain size, solid solution hardening and in stacking-fault energy, both of which are dependent on alloy chemistry, affect the cyclic stress-strain curve, the dislocation patterning behaviour and ultimately the initiation and growth of fatigue cracks. Knowledge gained from experimental studies will be used to guide development and validate crystal plasticity simulations undertaken in collaboration with Prof Dunne in Engineering Science.

Also see homepages: Steve Roberts Angus Wilkinson

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
M R 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 Q optical microcavities for solid state cavity QED
Dr Jason Smith

We are currently developing large arrays of high quality tunable optical microcavities and using them to modify the photon emission properties of nanomaterials such as diamond colour centres and semiconductor nanocrystals. Our work focuses on cavity fabrication, the basic science of the emitter/cavity quantum systems, and exploring their use as single photon sources, microlasers, and in a range of sensing and spectroscopic applications. The new project will involve further developing the cavity fabrication techniques (using focused ion beam milling), and performing experiments to characterise the cavities and the cavity/emitter systems. Particular directions of focus may include increasing the cavity quality factors sufficiently to enter the strong coupling regime, developing nanocrystal-based semiconductor microlasers, or exploring their use in advanced sensing and optical characterisation applications.

Also see homepages: Jason Smith

High resolution imaging and spectroscopy beam sensitive materials - Gentle STEM
Prof P D Nellist

By the very nature of their length scales, nanoscale materials require imaging and analysis techniques at resolutions approaching individual atoms. Transmission electron microscopy (TEM) can provide such capability. Many nanoscale materials, however, are also formed from low atomic number materials, such as carbon nanotubes and biological macromolecules, and tend to be damaged by electron beams. The aim of this project is to develop advanced electron microscope detectors and develop strategies for the characterization of materials with minimum electron exposure. Initial applications of the techniques developed will range from doped carbon nanotubes to polymer materials.

Also see homepages: Peter Nellist

Hydrogen-bonded chiral supramolecular networks
Dr. M.R. Castell

In this project molecular networks are synthesized through self-assembly on metal and oxide 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.

Also see homepages: Martin Castell

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

Imaging and spectroscopy of doped carbon nanomaterials
Prof P D Nellist, Prof N Grobert, Dr J R Yates, Dr R J Nicholls

The very small (~0.1 nm) beam widths available in the scanning transmission electron microscope allow for extremely high resolution imaging and spectroscopy of materials. Such an approach is extremely powerful for investigating carbon-based nanostructures, such as carbon nanotubes or graphene, that contain heteroatoms (e.g. nitrogen, boron and phosphorous). The incorporation of heteroatoms can be used to modify the growth processes of such materials and to control their response to mechanical deformation or electrical transport. By combining imaging and spectroscopy of such materials with simulations of bonding and structure using density functional theory calculations, we aim to further understand the mechanisms by which heteroatoms can modify the properties of carbon nanostructures.

Also see homepages: Nicole Grobert Peter Nellist

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

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

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

Manipulating spin qubits in diamond
Dr Jason Smith, and Dr John Morton

Electron spins on colour centres in diamond show excellent prospects for use in quantum information technologies, offering long coherence times (tens of milliseconds) and the ability to initialize, manipulate, and read out the spin state – all prerequisites for quantum information processing. The aims of this project will be to develop advanced spin control techniques for single colour centres, such as the well established nitrogen-vacancy centre, using pulsed microwave signals. It will be co-supervised by Dr Jason Smith, head of the photonic nanomaterials group, and Dr John Morton, a Royal Society URF working on electron spin resonance. Focus will be on adapting techniques from ‘bulk’ ESR spectroscopy (eg ‘Bang Bang’ pinning), to use on single electrons and nuclei in the solid state.

Also see homepages: Jason Smith

Mechanism and Modelling of Superplastic Deformation
R.I. Todd

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, SEM, mechanical testing over a range of temperatures and nanoindentation.

Also see homepages: Richard Todd

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 Oxide Photovoltaics
Dr Andrew Watt

The leading second generation thin film solar cells are made of copper indium gallium diselenide and cadmium telluride. Significant market penetration of these systems is hampered by their toxicity and use of expensive rare earth metals. There is growing need to develop new second generation thin film photovoltaic materials which are robust, low energy cost, lower toxicity and recyclable. The project will examine visible light absorbing metal oxide semiconductors which we have developed and proven to work effectively in solar cell devices. The project will involve, deposition of thin films visible light absorbing ternary metal oxide, fabrication of solar cell devices, power conversion efficiency and spectral response measurements and some physicochemical characterization eg XRD, SEM, XPS, TEM. There is a commercial license associated with this project and close industrial collaboration and further IP generation is expected.

Also see homepages: Andrew Watt

Metal-Organic-Semiconductor Nano-composites Transparent Conductors
Dr 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 percolated networks of metal nano-particles in a porous hosts, thin film processing on a variety of substrates, conductivity and mobility measurements along with some physicochemical characterization eg XRD, SEM, XPS, TEM. There is IP generated within the research group associated with this project and close industrial collaboration and further IP generation is expected.

Also see homepages: Andrew Watt

Micromechanical testing of individual grain boundaries
A J Wilkinson / S G Roberts / R I Todd

Marked differences exist in the mechanical behaviour of different types of grain boundaries in metals and alloys and this has a large impact on their overall mechanical properties. Within this project we will further develop our micro-mechanical testing methodologies so as to study a range of grain boundary behaviours, including dislocation generation, slip transfer/transmission, grain boundary sliding as a function of grain boundary geometry. A focus ion beam (FIB) will be used to fabricate micro-cantilever beams which contain a single isolated grain boundary. Load-displacement data for the deformation of such micro-cantilevers will be generated using a nano-indenter. AFM, EBSD and TEM methods will be used to characterize the grain boundaries and micro-cantilevers before and after deformation. Studies will centre on simple model systems (ie elemental metals) and be aimed at generating fundamental understanding of grain boundary related phenomena.

Also see homepages: Steve Roberts Richard Todd Angus Wilkinson

Micromechanical testing of Zirconium and it alloys
A J Wilkinson

Zr and its alloys are of great importance within the nuclear industry and are used in safety critical components. Their elastic and plastic properties are known to be highly anisotropic so that deformation processing leads to strong crystallographic textures and significant directionality in the performance of the final product. There are still significant gaps in the fundamental understanding of deformation in these systems. For example, the few data available for critical resolved shear stress (CRSS) in the literature show huge scatter, and do not even agree on which slip systems are the most easily activated. In this project a FIB will be used to machine micron-scale cantilever beams within suitably oriented grains of polycrystalline samples, which will then be taken to a nano-indenter for mechanical testing. The elastic and plastic behaviour will be analysed by comparing experimental load-displacement data with the response of finite element crystal plasticity simulations, so as to determine Young’s modulus and CRSS values. In the latter stages of the programme methods may be adapted to explore the effects of irradiation damage, hydride percipitates and/or temperature on the mechanical deformation.

Also see homepages: Angus Wilkinson

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. 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 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

Molecular alloy crystals
M R 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.

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 in Australia and for suitable systems prototype catalytic studies. Within this project there may be opportunities for an extended work period in Australia.

Also see homepages: Angus Kirkland

Nanomaterials for quantum information processing
GAD Briggs / A Ardavan (Department of Physics) / JJL Morton / K Porfyrakis / JH Warner

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 we are part of the world wide race to develop a scalable quantum computer. 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 and molecular species inside a cage that separates them from the quantum environment. We can insert fullerenes into carbon nanotubes to create one-dimensional 'peapod' arrays, which we can image by HRTEM, and we are also developing other schemes for molecular self-assembly of fullerenes and other functional molecules. We can also use other materials such as doped silicon and diamond. We can store the quantum information in 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 will be possible to develop sensors that exceed the standard quantum limit. By storing information holographically in collective spin states, it will be possible to process quantum information in large ensembles of spins. There will be several projects with these nanomaterials, ranging from synthesis and characterization 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 (qsd.materials.ox.ac.uk). In association with the experimental programme which will take place within a large and active research group (www.qipirc.org), there will be theory and modelling projects with Dr S C Benjamin, Dr J Fitzsimons, Dr B W Lovett and Professor J H Jefferson (www.qunat.org). There may be possibilities for industrial support and for international travel and collaboration.

Also see homepages: Andrew Briggs John Morton Kyriakos Porfyrakis Jamie Warner

Nanoscale mapping of local strains in semiconductors
A J Wilkinson

Our development of cross-correlation based analysis of EBSD has produced a step change in performance allowing elastic strain and lattice rotations to be measured in the SEM at high spatial resolution and with sensitivity that is competitive with large synchrotron facilities. The project will continue pushing this development by establishing routes to determine the detector geometry with the accuracy required to allow the use of dynamical diffraction simulations as reference patterns. This will dramatically increase the scope of the method. The method will be use it to map strains distributions in a variety of semiconductor devices and structures, including (i) GaN epilayers which have been grown using lateral overgrowth from misfitting substrates in an attempt to minimise defect density, (ii) SiGe epilayers grown on Si, and GaAs/AlGaAs vertical cavity surface emitting laser structures. The EBSD analysis will be complemented by finite element modeling of strains distributions and cathodoluminescence, AFM and TEM observations as appropriate.

Also see homepages: Angus Wilkinson

New detectors for transmission electron microscopy
A Kirkland / P R Wilshaw / G. Moldovan

Current generation imaging detectors for Transmission Electron Microscopy rely on a complex electron-photon conversion chain with the photons being detected by Charge Coupled Devices. As a result the overall sensitivity of these systems is poor and they are limited in their frame rate. We aim to construct the next generation of direct electron detector and this project will involve both simulation and fabrication of prototype devices.

Also see homepages: Angus Kirkland Peter Wilshaw

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 passivation processes for semiconductor surfaces
Dr P.R. Wilshaw, Dr J.D. Murphy, Dr S.C. Speller

Carrier recombination at surfaces and interfaces in solar cells reduces their effciency. We are devloping new processes which can be applied in a laboratory environment and perhaps, in the future, in an industrial context to passivate these structures. Our work focusses on manipulating the electrical charge associated with surface dielectric layers to repel the carriers from the interface so that recombination is mainly eliminated. We are investigating SiO2, Al2O3 and TiO2.

Also see homepages:

Novel processing of nanostructured films for energy storage
P S Grant

This project will study a new and scaleable spray deposition technology developed at Oxford that can produce thin films (0.5micron up to 10’s of microns) from aqueous and non-aqueous suspensions of nanomaterials over areas of (currently) up to 750cm2. In particular, the processing of 1D nanostructures (rods and wires) of transition metal oxides into large area meso-porous films for supercapacitors and battery/photovoltaic hybrids will be studied. As well as the synthesis of nanostructures and their suspension, the project will focus on the manufacture of the films themselves with a particular emphasis on the scaleability and reproducibility of any developed approaches. Both single material meso-porous films formed from rods, wires and tubes, and hybrid or composite structures comprising mixtures of materials, for example to optimise energy storage and mechanical stability, will be studied in terms of their processability, microstructure and energy and power performance in real supercapacitor configurations.

Also see homepages: Patrick Grant

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

Optical resonators in ultrapure diamond
Dr Jason Smith

Diamond is optically transparent throughout the infrared, visible and into the ultraviolet region of the spectrum, and its refractive index is relatively insensitive to temperature, making it highly attractive for producing stable optical resonator structures. Such structures could have a number of uses, from classical optical switches, to microcavities for housing quantum bits (qubits) for quantum computing. The difficulty is that processing diamond into microstructures is highly challenging as its chemical inertness makes it resistant to most etches. New plasma etching techniques developed by our collaborators at the University of Strathclyde Institute of Photonics look extremely promising in this regard, and the project will be to design and characterize resonators and waveguides based on thin films of diamond. The project will also involve interaction with the Quantum Photonics group at the University of Bristol.

Also see homepages: Jason Smith

Optical sectioning in aberration-corrected microscopy
Prof P D Nellist, Prof A I Kirkland

The development of correctors for the inherent aberrations of electron optics has revolutionized the spatial resolution achievable in transmission electron microscopy (TEM), which now can reach below 0.1 nm. Accompanying this improvement in lateral resolution is a dramatic reduction of the depth of field of the microscope. This reduced depth of field offers the opportunity to perform three-dimensional imaging and spectroscopy on materials by focusing the microscope at specific depths within a sample, a method known as optical sectioning. The aim of this project is to apply a variety of imaging modes, including confocal TEM which we have recently developed in our group, to investigate the optimal ways to access the three-dimensional information. Applications include novel transistors in the latest microprocessor, and crystal defects in solid-state lighting materials.

Also see homepages: Angus Kirkland Peter Nellist

Optical spectroscopy of nanomaterials
F Giustino

Many of today's most advanced solar cell concepts are based on the idea that sunlight can be harvested by using nanomaterials with high extinction coefficients, such as polymers, or nanomaterials with tunable optical absorption wavelengths, such as semiconductor quantum dots. For both categories a crucial feature is that the light harvesting takes place though the generation of bound electron-hole pairs called excitons, and is profoundly affected by the reduced dimensionality and by the nanoscale size of the light absorber. In this DPhil project we want to develop computational tools for investigating the mechanism of light harvesting in nanomaterials from an atomic-scale perspective. In particular we will develop methods for calculating excitonic properties such as exciton binding energies, exciton wavefunctions, and optical absorption spectra of nanomaterials. We are currently developing a technique for studying electronic excitations in large systems using quantum-mechanical methods based on density-functional theory. In this project we will extend that approach to the calculation of optical excitations in large systems, and we will investigate the excitonic properties of polymers and semiconductor quantum dots. This is a development-oriented project suitable for a student with a keen interest in condensed matter theory, programming, and high-performance scientific computing. [http://dx.doi.org/10.1103/PhysRevB.81.115105]

Also see homepages: Feliciano Giustino

Phase separation in thin film polymers
Dr Hazel Assender

The project will examine phase separation processes in thin film polymers, comparing the processes and kinetics in thin film systems with those in the bulk.

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

Processing of novel topological insulators in thin film form
S.C. Speller / C.R.M. Grovenor

Very recently, a new class of functional materials have been discovered that are bulk insulators with exotic metallic states at their surfaces, called topological insulators. These materials are particularly exciting because electron transport at these surfaces is insensitive to scattering by impurities, making them attractive for spintronics and quantum computing applications. This project involves the development of processing strategies for fabricating by sputtering high quality thin films of topological insulators such as Bi2Se3. X-ray diffraction will be used to study the crystal structure, phase purity and texture of the thin films, SEM/EDX will be used to study the local chemical composition and TEM for detailed examination of microstructure. Measurement of electrical properties will be carried out with our collaborators at the University of Leeds.

Also see homepages: Chris Grovenor Susannah Speller

Production of Semi-Insulating Silicon for High Frequency Devices
P R Wilshaw / Kanad Mallik

This project will provide an opportunity to research the making of semi-insulating (resistivity of 10-100kohm-cm) silicon-on-insulator (SOI) substrates grown by the Czochralski technique for microwave monolithic integrated circuits (MMIC). This has been identified as a novel substrate material in the ITRS Roadmap and has the potential to bring about a paradigm shift in the semiconductor industry.

The research involves enhancement of the resistivity of SOI handle wafers by doping with transition elements, which introduce deep impurity levels in the silicon energy band gap. Another challenging aspect of the research is to confine these dopants to the handle wafer by use of diffusion barriers. The work will provide an excellent opportunity to get training and gain experience in a wide range of experimental skills in modern semiconductor science and technology. For example:

Transition element doping techniques, including ion implantation and diffusion.
Characterization techniques like, deep level transient spectroscopy (DLTS), secondary ion mass spectroscopy (SIMS), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and microwave absorption measurements.
Some of the characterisation experiments will involve training in high vacuum techniques and cryogenics.
Semiconductor device fabrication using photolithography.
Working in semiconductor-grade cleanrooms in Southampton and Oxford.
There is also scope for numerical modelling work concerning the electronic properties of semiconductors and microwave device simulation.

The student will work in a team involving members of the Department of Materials, Oxford, the Electronic Engineering Department, Southampton, a multi-national Si wafer manufacturer, and a UK/EU semiconductor device manufacturer.

Also see homepages: Kanad Mallik Peter Wilshaw

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
M R 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 dynamics of electron and nuclear spins
JJL Morton / A Ardavan (Department of Physics)

Magnetic domains, each consisting of vast numbers of magnetic atoms, have been used for decades for information storage, for example in hard disk drives. New models for computing have been put forth in which information is encoded at a much deeper level, within the spin of individual nuclei, atoms and molecules, and calculations performed through the interactions between spins. The nature of this information inherits the quantum mechanical properties of the spin states, such as superposition, allowing certain computations to take place at dramatically faster rates than in conventional computers.

We study the quantum dynamics of electron and nuclear spin systems, principally using magnetic resonance, to establish i) how best to exploit spins in condensed matter for quantum information applications; ii) the environment of the spin, which can tell us about materials properties, molecular structures, conformation changes, and relaxation mechanisms; iii) the interaction of spins with other excitations, to allow detection of magnetic resonance through optical or transport phenomena; iv) ...and much more!

This research is highly interdisciplinary and includes the development of novel instrumentation and techniques for the coherent manipulation of electron and nuclear spin states. There are extensive opportunities for international travel and collaboration.

Also see homepages: John Morton

Quantum Information Processing
B W Lovett / S C Benjamin

The Quantum and Nanotechnologies Group (www.qunat.org) anticipates that they will be able to offer one or more doctoral studentships in the area of quantum information processing. The group has broad interests, ranging from detailed modelling of semiconductor structures through more abstract ideas related to designs for quantum computer architectures and extending to fundamental questions about the nature of quantum information and measurement. At the time of writing the following are active projects:

i) Measurement based quantum computing. One can regard quantum entanglement as the fundamental resource needed in order to execute quantum algorithms. Certain kinds of entangled states exist which are universal resources, in the sense that _any_ quantum algorithm can be performed simply by performing a prescribed series of quantum measurements. Moreover, even the entangled state itself can by created by making measurements. These insights have led to many new possible implementations of quantum computers, for example: one that uses only photons, one exploiting crossed atomic beams and others based on optical measurements on colour centres in diamond.

Specific topics are: first principles physics of measurement, implementation of error correction or avoidance and entanglement creation by measurement.

ii) Nanomaterials and quantum computing. We are looking at how certain nanomaterials (such as quantum dots, molecules or crystal defects) can be used to implement quantum gate operations. We have developed methods for coherent quantum control of systems with a range of Hamiltonians. We are also interested in modelling decoherence, which is caused by the interaction of a system with its environment, and employs the theory of open quantum systems.

iii) Spin chains. One of the most important questions in quantum information processing is how we might transmit information from one computer to another. We have been looking at at this might be done using one (or higher) dimensional arrays of interacting spins (or similar quantum two level systems). An important theme is to achieve is much as possible with minimal external control --- in other words, to exploit the 'natural' dynamics of the spin system as completely as possible.

Another potential application of a spin chain is as a globally controlled quantum memory element. We are interested in developing the theory of molecular quantum memories, for both interacting and independent molecular systems.

There are several collaborators on these projects, including Dr Tom Stace (University of Queensland), Prof Sougato Bose (University College London), and Prof Leong Chuan Kwek (National University of Singapore). Currently no specific funding is in place; however, a number of funding routes exist and we would be happy to advise strong students about how to explore these.

Also see homepages: Simon Benjamin Brendon Lovett

Quantum photonics and spintronics of colour centres in diamond
Dr Jason Smith and Dr John Morton

Diamond colour centres have demonstrated exquisite properties as single photon sources and quantum spin registers that operate even at room temperature, providing great opportunities for quantum communications and information technologies. This project will involve using optical microscopy, spectroscopy, and spin resonance techniques to characterise the underlying physics and properties of single colour centres, including the well established nitrogen-vacancy defect, and the '532' centre from which we have recently seen the first single photon emission. Principal collaborations are with Element Six Ltd and the Diamond Trading Company.

Also see homepages: John Morton Jason Smith

Reactive Metal Nanoparticles for Batteries
Dr Andrew Watt

Recently we discovered a new method for producing highly reactive metal nanoparticles (eg aluminum, lithium) in large volumes and under environmentally friendly conditions. The process overcomes the major barriers for using reactive metals as materials in batteries or hydrogen generators; (1) there is no surface oxide to prevent reaction, and (2) the nanoparticles are so small that once the reaction has taken place all metal has been reacted so there is no waste. The objective of this project is to utilize Aluminum’s superior energy density to weight ratio, zero emissions potential and minimal toxicity to produce a hydrocarbon replacement fuel source.

Also see homepages: Andrew Watt

Recombination at extended defects in silicon solar cells
Dr J.D. Murphy

Solar cells made from multicrystalline silicon (mc-Si) make up more than half the market for photovoltaics at present. Mc-Si contains a host of defects, including grain boundaries, precipitates, dislocations and transition metal point defects. All these defects act to reduce the efficiency of the final cell as they act as recombination centres for photo-generated charge carriers. In this project, the minority carrier lifetime is studied by quasi-steady-state photoconductance (QSS-PC). Model systems (e.g. oxide precipitates) are used in order to isolate and understand the effects of individual defects. Some samples are intentionally contaminated with transition metals, to understand the effect of transition metal decoration on the recombination activity of extended defects. The project is performed in collaboration with leading suppliers of silicon to the photovoltaic industry.

Also see homepages: John Murphy

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

Reverse-engineering the atomic-scale structure of dye-sensitized solar cells
F Giustino

Among the many innovative photovoltaic concepts currently under consideration, dye-sensitized solar cells based on mesoporous TiO2 films sensitized with molecular dyes have gained prominence due to their relatively high energy conversion efficiencies in excess of 10%. In these devices the photocurrent is generated via ultrafast electron transfer from the photoexcited dye to the nanostructured semiconductor. Since the electron injection takes place within a sub-nanometer length scale, the atomistic nature of the dye/semiconductor interface plays a critical role in the performance of dye-cells. Determining the atomic-scale structure of TiO2/dye interfaces is a formidable task, because there exists a very large number of possible geometries and bonding configurations. In this DPhil project we will determine the atomistic structures of dye-cell interfaces by reverse-engineering measured X-ray photoemission spectra and measured infrared absorption spectra using first-principles calculations. Since these spectra are very sensitive to the local bonding environment, they carry the signature of the interface structure at the atomic scale. This project will focus on the most advanced dye-cell configurations, including organic dyes and alternative metal-oxide substrates. Computational techniques include density-functional theory, core-level spectroscopy, vibrational spectroscopy, and molecular dynamics. This DPhil project will involve the extensive use of high-performance parallel computers. Interactions with experimental groups both in Oxford and overseas are anticipated. [http://dx.doi.org/10.1103/PhysRevB.84.085330]

Also see homepages: Feliciano Giustino

Roll-to-roll manufacture of organic transistors
Dr Hazel Assender

We are seeking to develop organic transistor devices on polymer substrates by roll-to-roll vacuum deposition using high-throughput molecular and polymer evaporation. The project will be to explore materials parameters for improved properties, and also the lifetime/degradation in performance of the device as a result of chemical degradation, and mechanical and thermal stresses on the devices.

Also see homepages: Hazel Assender

Semiconductor nanocrystal sensors
Dr Jason Smith

Semiconductor nanocrystals grown by wet chemical methods are rapidly becoming a key functional material that are finding applications in fields as diverse as life sciences, solar power generation, and telecommunications. It is well known that the chemistry of the nanocrystals’ surface profoundly affects their electronic properties, and the fluorescence from single nanocrystals displays a number of interesting dynamic phenomena such as random blinking and spectral drift due to the Quantum Confined Stark Effect which can potentially be harnessed for use as sensors of the local environment. The aim of this project will be to develop techniques for using changes in the fluorescence properties of nanocrystals to sense changes in the surroundings. It will build on recent work to develop a fluidics device and electrical gating structures compatible with single nanocrystal photoluminescence measurements.

Also see homepages: Jason Smith

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

Spray forming of hierachical metal-metal composites
P S Grant

Spray forming is a high technology casting process for producing large scale advanced alloys with unmatched quality and performance. This project will explore spray forming for the processing of “designer” alloys by co-spraying a second (or more) liquid or metal phase into the primary sprayed alloy so that co-deposition and mixing occur to produce unusual and potentially highly useful structures and properties. This project will make use of the leading spray forming facilities at Oxford to manufacture and study hierachical metal-metal composites in which microstructural features at the nano, micro and meso scale are attempted to be controlled separately by co-spraying of different materials, from the simplest mixture of two pure metals that are then heavily deformed to produce nanofibrils, through to the co-injection of nanoscale powders and mixing of different liquid sprays to produce in-situ reactions and otherwise difficult to process compositions and phases. The microstructure and mechanical properties will be studied for the most promising combinations, together with the effect of downstream processing operations.

Also see homepages: Patrick Grant

Strained layer epitaxy of oxide on oxide islands
M R Castell

We have recently done some innovative work on anatase TiO2 and BaTiO3 epitaxy on SrTiO3 (001). The results of both these streams of work indicate that there is plenty of scope to expand these efforts into a coherent programme related to oxide strained epitaxy. The idea is to grow thin oxide layers on oxide substrates that have a slight lattice mismatch. The strain that builds up in the oxide layer will then affect its electronic properties such as the bandgap. There is a strong foundation of strain induced electronic structure engineering in semiconductors, and this project is to expand these ideas into oxides.

Also see homepages: Martin Castell

Studies of metal nanocrystals on Strontium Titanate
M R Castell / A I Kirkland

It is possible to grow a variety of metal nanocrystals on clean single crystal strontium titanate surfaces. Such particles often adopt novel morphologies which can be controlled and which may provide novel catalysts and gas sensors. For example, silver nanocrystals with fivefold symmetry have been observed, and palladium crystals have been shown to change their shape depending on the detailed atomic structure of the substrate. This project aims to characterize these materials with atomic resolution, using both scanning tunnelling microscopy (STM) and transmission electron microscopy (TEM) in an attempt to understand their growth and structure.

Also see homepages: Martin Castell Angus Kirkland

Superconducting metamaterials
Dr Susannah Speller/Professor Chris Grovenor

Metamaterials - composites designed with spatially varying dielectric and/or magnetic properties - are of great interest internationally for novel communications devices. Working alongside the team involved in the £5m EPSRC Programme Grant QUEST (http://www.quest-spatial-transformation.org/research.html), this project involves the fabrication of polymer/superconductor composite materials to extend the range of performance of conventional metamaterials and to allow the design of more sophisticated communications systems. The student will become trained in a wide range of composite processing techniques, and will carry out microstructural and electromagnetic characterisation using techniques including electron microscopy, high frequency testing and SquID magnetometry. There will be opportunities to spend time in the laboratories of our partner universities; Queen Mary, University of London, and Exeter University.

Also see homepages: Chris Grovenor

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
M R 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.

Also see homepages: Martin Castell

Three-Dimensional Damage in Quasi-Brittle Materials
Prof James Marrow

Quasi-brittle materials have brittle, porous, aggregate microstructures with a capacity to modify, or limit elastic strain energy storage. Graphite, concrete and SiC-SiC composites are such materials, and in applications such as 4^th generation nuclear fission and fusion power plants their structural integrity is critical. Knowledge of their damage tolerance is important. It is critical to be able to predict the circumstances in which microstructure degradation can lead to “cliff-edge” accelerations in the deterioration in mechanical properties. An understanding of the mechanisms and heterogeneity of damage development in such materials is required to reduce unnecessary conservatism in design and operation.

In this project, we will quantify the three-dimensional development and coalescence of damage in quasi-brittle materials using three-dimensional image correlation of X-ray tomography data. Microstructure-based models for three-dimensional and multiple-crack interactions in heterogeneous aggregates will be developed. The sensitivity of damage development to the stress state in small specimens will be studied. This will help us understand how data from test specimens may be used to predict the behaviour of large and complexly shaped components.

The student will collaborate with the Oxford Martin School Research Fellow in the Materials Department, in a project developing tools for three-dimensional studies of materials for energy, and will benefit from strong links with the Henry Moseley X-ray Imaging Facility, at the University of Manchester, where some of the experimental work will be conducted.

Also see homepages: James Marrow

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

The fracture resistance of engineering materials is measured using standard two-dimensional test specimens. But real cracks and engineering components are three-dimensional, 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.

Digital correlation image analysis, combined with new X-ray tomography techniques, allows precise, in-situ, measurement of the material displacements inside solid samples. In an optimisation approach that combines these novel observations with finite element modelling of deformation and damage, we will investigate the propagation of three-dimensional cracks in a range of engineering and model materials. Our aim is to validate the current design rules for complex crack shapes and their interactions with three-dimensional stress gradients.

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

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 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 develop 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 University College Davis in the USA and with the MRC laboratories in Oxford.

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

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