Avalanche Photodiodes Based on the AlInAsSb Materials System

We report avalanche photodiodes (APDs) fabricated from high-aluminum-content Al x In 1− x As y Sb 1− y lattice matched to GaSb that is grown within the miscibility gap using a digital alloy approach. The material was initially characterized through a series of Al x In 1− x As y Sb 1− y ( x = 0.3, 0.4, 0.5, 0.6, 0.7) p-i-n structures. In order to achieve operation at telecommunications wavelengths, an Al x In 1− x As y Sb 1− y separate absorption, charge, and multiplication APD has been developed. Very low excess noise, as characterized by k ∼0.01−0.05, has been achieved.