Periodic Reporting for period 1 - NP-SPAD (Uncooled Nanopillar Single-Photon Avalanche Diodes (NP-SPADs) at Telecommunication Wavelengths)
Periodo di rendicontazione: 2020-01-01 al 2021-12-31
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.
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.
The project was implemented through 5 different experimental and simulation work packages (WPs). In WP1, bottom-up p-n GaAs and p-i-n InGaAs nanopillars and InGaAsP/InP planar thin films for top-down etch were grown. In WP2, fabrication process was optimized using p-n GaAs nanopillar and then the optimized fabrication process was used for fabricating p-i-n InGaAs nanopillar devices. In WP3, both p-n GaAs and p-i-n InGaAs were characterized for I-V (room temperature and low temperature) and C-V (approximate doping). Photocurrent was also measured for p-i-n InGaAs nanopillars. In WP4, preliminary Gm-APD model for planar SAM-APD structure was developed and ex-situ PECVD nitride (SiNx) passivation was investigated on InGaAs nanopillars and a simulation model was developed. Lastly, in WP5, p-i-n InGaAs nanopillar devices were bonded to chips and top down etched InP and InGaAsP/InP nanopillars were fabricated, further µ-photoluminescence study was carried out to investigate their surface quality following digital etching. The dissemination of the project will continue even after the official end date with scientific papers in various stages of preparation to be published soon.
We pushed the state of the art in bottom-up and top-down nanopillar device fabrication. We investigated ex-situ nanopillar passivation and surface passivation model. We also investigated ensemble p-n GaAs nanopillar devices. We have also paved the foundation for top-down etched InGaAsP/InP nanopillar devices. These results will no doubt open new areas of investigation into III-V nanopillar devices.
On a personal level, this fellowship has further provided the fellow with the opportunity to experience excellent multidisciplinary research while being involved in cutting edge research. This will no doubt have a tremendous impact on his research career going forward. The fellow also gained valuable experience in preparing and applying for research funding grants that he plans to use for writing future grants, thus providing novel opportunities for future research endeavors.
On a personal level, this fellowship has further provided the fellow with the opportunity to experience excellent multidisciplinary research while being involved in cutting edge research. This will no doubt have a tremendous impact on his research career going forward. The fellow also gained valuable experience in preparing and applying for research funding grants that he plans to use for writing future grants, thus providing novel opportunities for future research endeavors.