Bilateral Geiger mode avalanche in InSe Schottky photodiodes
Dongyang Zhao, Yan Chen, Hu Tao, Hechun Cao, Xuefeng Zhao, Yu Jia, Xudong Wang, Hong Shen, Jing Yang, Yuanyuan Zhang, Xiaodong Tang, Wei Bai, Jianlu Wang, Junhao Chu
Abstract
Avalanche photodiodes are crucial in emerging weak light signal detection fields. However, most avalanche photodiodes either suffer from relatively high breakdown voltage or relatively low gain, impairing the advantages of avalanche multiplication. Herein, we report the bilateral Geiger mode avalanche in two-dimensional Graphene/InSe/Cr asymmetrical Schottky junction. A high gain of 6.3 × 107 is yielded at low breakdown voltage down to 1.4 V approaching InSe’s threshold limit of bandgap. In addition to the separated carrier injection region and avalanche multiplication region, a positive temperature coefficient of the ionization rate and a very low critical electric field (11.5 kV cm–1) are demonstrated, leading to the nice performance. Such device architecture also enables low dark current and noise equivalent power, showing weak light signals detection ability down to around 35 photons at room temperature. This study provides alternative strategies for developing energy-efficient and high-gain avalanche photodiodes. Zhao et al. report bilateral Geiger mode avalanche in 2D graphene/InSe/Cr asymmetrical Schottky junction. The asymmetrical Schottky junction benefits to initiate impact ionization and multiplication for the injected majority carriers, leading to a multiplication factor up to 10 ^ 7 and a breakdown voltage of 1.4 V.