GeSi APD with Ultralow Dark Currents for LiDAR

Abstract

We report the fabrication and characterization of a 50-µm diameter GeSi avalanche photodiode (APD) in normal incidence configuration. The dark currents at unity gain and gain of 10 are measured to be 0.24 nA and 2.4 nA, respectively, demonstrating roughly 2 and 3 orders of magnitude reduction compared to the previously reported Ge-on-Si APDs, and out-performing many of the corresponding group III-V APDs in the literature. 3D point cloud (PCL) images are taken using the fabricated GeSi APD as proof of concept for time-of-flight (TOF) based light detection and ranging (LiDAR).