Optimization of Surface Passivation for InAs-GaSb Infrared Photodetector

A type II indium arsenide / gallium antimonide (InAs-GaSb) strained layer superlattice (SLS) semiconductor is optimal for detecting long wavelength infrared (LWIR) signals for infrared imaging applications. However, as with all crystal structures dangling bonds at the surface of the semiconductor must be pacified with a passivant to maintain the integrity of the semiconductor. We report the most effective passivation layer for this III-V semiconductor by examining both the material and device characteristics of the devices pacified by silicon dioxide (SiO 2 ), silicon nitride (Si x N y ), and zinc sulfide (ZnS). Our final reporting shows ZnS with a pre-passivation of ammonium sulfide ((NH 4 ) 2 S) as being the most effective passivant.