AlInAsSb Separate Absorption, Charge, and Multiplication Avalanche Photodiodes for Mid-Infrared Detection

We report AlInAsSb separate absorption, charge, and multiplication (SACM) avalanche photodiodes with a >3- $\mu \text{m}$ optical cutoff, operating at 240 K. Gain and dark current performance further improve with reduced temperature. 65% external quantum efficiency at 2- $\mu \text{m}$ is achieved without anti-reflection enhancement.