Earth abundant chalcogenides for silicon photonics

A 3.5 year fully funded PhD studentship is available in the Department of Physics at the University of York co-supervised by Dr Yue Wang and Prof Keith McKenna.

Computers form the backbone of modern society and the digital economy. However, since 2010 CPUs have reached the maximum speed they can practically sustain - limited by the intrinsic loss in electrical wires. To overcome this limit, electrical wiring must be replaced by optical wiring, while continuing to use the mature silicon technology platform.

The current industrial solution is to mount efficient light emitters such as III-V semiconductors on silicon, but this approach is rather expensive and complicated. What is needed is an efficient and low-cost light emitting material that is compatible with silicon. One can easily identify the requirements of the required light emitting material: it should be stable, have a direct band-gap of around 1 eV and type-I band alignment to Si, be composed of low-cost and earth-abundant elements, and be suitable for mass production.

In this project, you will use density functional theory to screen prospective materials and identify candidates with the required stability and electronic properties. The search will focus on chalcogenide materials, which have proven to be a very fertile ground for the discovery of semiconductors for applications in optoelectronics and photovoltaics (e.g. CuInSe2, Sb2Se3 and Cu2ZnSnS4). However, their potential for on-chip optical interconnects remains relatively unexplored.

Once prospective materials are identified you will produce corresponding thin film samples and characterise them using techniques such as absorption and photoluminescence, AFM and SEM. In the latter stages of the project the materials will be combined with silicon devices to make light emitting diodes in order to test their suitability for optical communication.

It is not expected applicants will have experience in both theoretical and experimental research techniques at the start of the project. Full training will be given within the research groups of Prof Keith McKenna (theory) and Dr Yue Wang (experiment). However, relevant experience in one of the areas would be desirable and a willingness to learn is essential.


Funding is available to UK and EU applicants and will cover tuition fees and a tax-free stipend at the standard rate (currently, £15,009 per year) for 3.5 years. The studentship is available to start in October 2020.