Suppression of leakage currents in InAsSb MWIR photodiodes by chemical treatment and illumination

摘要

Novel surface treatments for an InAs_(0.91)Sb_(0.09) p-n junction grown on GaSb by MOCVD are proposed and demonstrated. Exposure of the p-n junction to argon ion plasma followed by etching with tartaric acid reduces the dark currents by five orders of magnitude. An additional reduction by two orders of magnitude in the dark current is achieved by illuminating the sample with white light. A mid-wavelength infrared photodetector based on the so treated p-n junction exhibits a high zero-bias resistance-area product (R_0A) of 2.7 × 10~7 Ω cm~2 and an internal quantum efficiency of 70% at 77 K. The measured BLIP temperature is 170 K and a high detectivity value (D~* _(BLIP)) of 4.03 × 10~(11) cm Hz~(1/2) W~(-1) is observed at 3.7 μm. The surface treatment results indicate that the device performance is limited by bulk material properties.