Engineering of Quantum Light Emmitters in Gallium Nitride

Gallium Nitride (GaN) is a wide bandgap semiconductor that can host emitters covering a wide spectral range from the ultraviolet to the near-infrared (400-1550nm). As a host for single photon emitters this material can offer a number of advantages, such as a less carrier escape at high temperature, a reduced rate of non-radiative surface recombination (relative to, say, GaAs) and low-cost GaN-on-Sapphire substrates.

Single photon emission has been demonstrated from point defects unintentionally introduced into as-grown material, strain driven self-assembly of quantum dots, or growth of nanowires with engineered emitters self-aligned to the nanowire centre. These nanowires can be most easily produced by selective area epitaxy using a titanium mask on a host substrate (which need not be GaN). The resulting nanowire may be shaped and tapered by the growth conditions to enhance the efficiency with which emitted light is collected.

This project lies part way between Physics and Engineering, making full use of the facilities of a newly established Institute for Compound Semiconductors. During the project the student will:
- Establish a micro-photo-luminescence system to map defects in as-grown GaN and characterise them.
- produce a literature review on the growth of III-Nitride nanowires.
- Carry out cleanroom processing of titanium masks for GaN nanowire growth
- Develop the growth of nanowire devices, which will involve handling wafers, optical and electron beam lithography, metal evaporation and etching.
- Investigate the non-linear optical response of these nanostructures
- Demonstrate resonant optical excitation of single emitters.