High efficiency detection of single photons at telecommunication wavelengths (notably at 1.55 µm) is critical for emerging technologies, such as free-space and on-fiber quantum information processing, eye-safe and long-distance light detection and ranging (LiDAR), and highly sensitive remote sensing. This research project aimed to meet this critical need by developing III-V nanopillar-based uncooled single-photon avalanche diodes (NP-SPADs). The overall objectives of the project were: (i) develop heteroepitaxy of III-V nanopillars (work package, WP1), (ii) optimize device fabrication process (WP2), (iii) demonstrate single photon detection (WP3), (iv) develop 3-D nanopillar GmAPD model (WP4), and (v) collaborate with European industrial partners (WP5). WP5 was contingent on the complete demonstration of single photon detection in WP3. Although the research for WP3 was completed, the outcome was not as expected and as such, WP5 was augmented to further the development of nanopillar SPADs using top-down etch method, alongside liaising with the industrial partners.
Despite the unforeseen difficulties resulting from the COVID-19 lockdown and subsequent restrictions, the project provided many important findings and avenues for developing nanopillar-based devices. The results will be published in scientific journals and presented in future conference.
The NP-SPAD project further helped the fellow achieve valuable experience through exposure to high-risk high-gain research, working in an internationally renowned multidisciplinary group, acquisition of new experimental expertise, and development of transferable skills. He also gained research experience in nanopillar surface chemistry, materials study, device physics, and plasmonics. This also includes mastering a range of novel nanomaterial, device, and optoelectronic characterization techniques.
