Semiconductor nanowires have shown great promise for the development of a wide range of optoelectronic devices such as lasers/LEDs, photodetectors and solar cells due to its nanoscale size and unique geometry-related properties. In particular, owing to their intrinsic small photon collection area and flexibility in junction design in both axial direction and radial direction, semiconductor nanowire based APDs have shown great promise to enable photocurrent gain and sensitivity down to the single photon level. In this project, we aim to develop III-V semiconductor nanowire based avalanche photodetectors (APDs) with ultra-high sensitivity towards single photon detection, as a new platform to enable numerous emerging fields of science, technology and application, including long-range free-space communications, time-of-flight 3D scanners, light detection and ranging (LiDAR), and quantum computing and information processing.

This project involves the design, fabrication and characterisation of III-V nanowire APD arrays. A simulation platform for combined optical and electrical simulation of nanowire APD will be developed to investigate the fundamental properties of light interaction with nanowire arrays and carrier transport within each individual nanowire and thus the design of more efficient infrared APD structures.

Through the project, the student will develop skills in the area(s) of:

• 3-D coupled optical and electrical simulation on nanowire APDs
• Material synthesis and device fabrication technologies within a cleanroom environment
• State-of-the-art nanofabrication techniques such as electron beam lithography and focussed ion beam processing
• Nanoscale material and device characterisation (structural, optical and electrical).

For PhD students 3rd year Condensed Matter Physics or Engineering Materials Science/Semiconductor courses are recommended but for undergraduate projects no special requirements.