The InGaAs single photon detector chip designed and prepared by Professor Wang Liang's research group of the Department of Optics and Optical Engineering of the University of Science and Technology of China has made great progress. The research team optimized the optical performance of single photon detector chips by designing metal-distributed Bragg reflectors, completed the independent design and preparation of single photon detector chips with low intrinsic dark count, and realized the localization of single photon detector chips, which made an important step forward to solve the frontier science and technology problems urgently needed by the country. The relevant research results are entitled "High performance InGaAs/InP single-photon avalanche diode using DBR-metal reflector and backside micro-lens". Published online in the Journal of Lightwave Technology, a leading journal in the field of electronic engineering technology.

The semiconductor single photon avalanche diode (SPAD) based on InGaAs material has the advantages of high sensitivity in single photon level, human eye safety in short-wave infrared band, low loss in atmospheric window band, haze penetration, low power consumption, small size, easy integration and so on. These advantages make SPAD play a huge role in quantum information technology, active and passive focal plane detector, urban mapping, Lidar and other fields, and have great civil, commercial and military value.

Professor Wang Liang's research team achieved epitaxial structure growth with low defect density and high doping accuracy by adjusting MOCVD growth parameters such as temperature, V/III ratio and doping concentration. Based on the structure of SPAD device, a new wide spectrum (all-optical communication band) total mirror, namely metal-distributed Bragg mirror, is proposed and designed to improve the photoelectric absorption efficiency of SPAD chip. The 12μm window low dark count SPAD prepared by the research team has an ultra-low intrinsic dark count of 127 Hz at a temperature of 233 K and a detection efficiency of 10%, which is an order of magnitude lower than similar foreign products, and has better device performance. This chip can meet the needs of single-photon detection in applications such as quantum communication and can replace imported devices.

图1（a）SPAD的器件结构示意图（b）12μm窗口的超低暗计数SPAD芯片及测试结果

Professor Wang Liang from the Department of Optics and Optical Engineering at the University of Science and Technology of China is the corresponding author of the paper, and doctoral candidate Zhang Bojian is the first author of the paper. This research was supported by the Ministry of Science and Technology of China, the National Natural Science Foundation of China and the Science and Technology Department of Anhui Province, as well as support from the School of Physics, China University of Science and Technology, the 13th Research Institute of China Electronic Science and Technology Group, China University of Science and Technology Research and Manufacturing Center, and the Key Laboratory of Quantum Information of the Chinese Academy of Sciences.

Paper link:https://ieeexplore.ieee.org/abstract/document/9720212

(Department of Optical and Optical Engineering, Department of Scientific Research, School of Physics)
Source: HKUST News Network