Very high gain and low noise GaAsSb/AlGaAsSb avalanche photodiodes for 1550nm detection at room temperature

The performance of the photodetector is often the primary limiting factor affecting a free space communication or LiDAR system's sensitivity. Avalanche photodiodes (APDs) can be used to improve the signal to noise ratio (SNR) compared to conventional p-i-n photodiodes. Our study focuses on demonstrating an APD operating in the eye-safe short-wave infrared (SWIR) spectrum (>1400 nm) with high multiplication (M>1200) and low excess noise (F<7 at M=200) at room temperature. This device utilizes GaAsSb and Al_0.85Ga_0.15AsSb in a separate absorber, charge, and multiplication (SACM) configuration on an InP substrate. Notably, this device exhibits more than 40 times improvement in maximum achievable multiplication and 6.5 times lower excess noise at M=25 compared to commercially available InGaAs/InP devices.