Low noise low dark current AlAsSb/GaAsSb digital alloy avalanche photodiode

This study introduces a digital alloy AlAsSb/GaAsSb avalanche photodiode (APD) on InP, demonstrating low dark current and low noise performance. The lattice-matched AlAsSb/GaAsSb APD structure exhibits a dark current density of 16 mu A/cm2 at a gain of 10 and an excess noise factor near 2 at room temperature, attributed to high crystal quality and effective passivation. The dark current level achieved in this work is the lowest reported for Sb-based p-i-n APDs with a 1000 nm thick intrinsic region. These results make it highly promising for separate absorption, charge, and multiplication (SACM) structures in optical communication and LIDAR applications. (c) 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement