Passivation of type II InAs/GaSb superlattice photodetectors

Leakage currents limit the operation of high performance type II InAs/GaSb superlattice photodiode technology. Surface leakage current becomes a dominant limiting factor, especially at the scale of a focal plane array pixel (< 25 μm) and must be addressed. A reduction of the surface state density, unpinning the Fermi level at the surface, and appropriate termination of the semiconductor crystal are all aims of effective passivation. Recent work in the passivation of type II InAs\GaSb superlattice photodetectors with aqueous sulfur-based solutions has resulted in increased R0A products and reduced dark current densities by reducing the surface trap density. Additionally, photoluminescence of similarly passivated type II InAs/GaSb superlattice and InAs GaSb bulk material will be discussed.