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.