Highly mismatched semiconductor production by molecular beam epitaxy for next generation photodetectors (EEE-22-Richards)

Details

Many modern technologies rely on the interaction of light and electron flows to produce different functionalities. In LEDs, flows of electrons are converted into light. Solar cells convert energy from sunlight into electrical potential energy. There are many modern devices that utilise more complex light / electronic interaction. In all cases, the nature of the interaction of light and electrons is dictated by the properties of the active material of the device, which in most cases is a semiconductor. There is a great range of mature semiconductor materials.

However, significant effort still goes into developing new semiconductor materials, and combinations of materials, for different applications. For example, the white light LED was made possible by the development of gallium nitride. Recent world record solar cell performances have been achieved by stacking different materials together effectively.

This PhD will investigate the production of semiconductors containing a small fraction of bismuth. This family of semiconductors has proven difficult to manufacture in the past due to the very large size of the bismuth atom. However, the device properties that can be achieved with this family of alloys makes them an attractive prospect if issues with their production can be overcome. Recent work has shown that bismuth atoms incorporate in a process mediated by specific configurations of atoms on the crystal surface. Understanding these configurations and their impact on the final alloy content and quality will be key to producing high-quality devices in the future.

The experimental work will involve growing crystals of the dilute bismide alloy indium aluminium arsenide bismide using a technique called molecular beam epitaxy. The samples grown will be characterised using in-house optical and structural analyses and will be sent to project partners at the University of Cadiz for extremely high-resolution imaging, which will enhance understanding of the material produced.

Interested candidates are strongly encouraged to contact the project supervisors to discuss your interest in and suitability for the project prior to submitting your application.

Please refer to the EPSRC DTP webpage for detailed information about the EPSRC DTP and how to apply.

Apply Here: Application Form (sheffield.ac.uk)