CZTS (Cu2ZnSnS4) is a semiconductor comprising Earth-abundant, cheap elements and is being researched as a sustainable material for solar photovoltaic cells. However despite extensive international efforts, it has failed to exceed 13% efficiency. There is therefore a major opportunity – if this limit can be overcome, CZTS would become viable as a large scale production technology that could compete with silicon, transforming the international PV market.
Technically the challenge is that CZTS has a much lower voltage (Voc) than is expected from its band gap. This is likely to be caused by grain boundaries in the thin film material. This project sets out to explore the idea that single crystal materials can be used to investigate the origin of the Voc limit in CZTS with the ambition of breaking its present limitation.
The project will be to grow single crystals of CZTS, to characterise their basic electrical properties, and to fabricate test PV devices from them in order to determine the efficiency-limiting mechanisms. Crystal growth and materials preparation will form a significant part of the project. Project specific training will include: crystal growth and characterisation, studies of deep and shallow electrical levels, carrier lifetime measurements, device fabrication, determination of the limiting aspects of device performance from idealised test devices. Hands-on training in thin film deposition, including sputtering and sublimation, plus device processing will follow. There will also be scope for the student to become involved with thin film polycrystalline CZTSS device fabrication.
Qualifications Required: First class degree in physics, chemistry or materials science. Excellent English (written and spoken) is essential.
Project Type: Experimental
Eligibility: UK or EU students only.
This studentship is funded by the EPSRC Centre for Doctoral Training (CDT) in New and Sustainable Photovoltaics. The CDT is a multi-centre team composed of seven universities that will provide dedicated training in PV to train highly-skilled students capable of transforming state-of-the art research and development across the sustainable energy and PV sectors. For more information see the CDT website