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