Evaluating the size-dependent quantum efficiency loss in a SiO₂-Y₂O₃ hybrid gated type-II InAs/GaSb long-infrared photodetector array

Abstract

Growing Y2O3 on 20 nm SiO2 to passivate a 11 μm 50% cut-off wavelength long-wavelength infrared type-II superlattice gated photodetector array reduces its saturated gate bias (VG,sat) to −7 V. Size-dependent quantum efficiency (QE) losses are evaluated from 400 μm to 57 μm size gated photodiode. Evolution of QE of the 57 μm gated photodiode with gate bias and diode operation bias reveals different surface recombination mechanisms. At 77 K and VG,sat, the 57 μm gated photodiode exhibits QE enhancement from 53% to 63%, and it has 1.2 × 10−5 A/cm2 dark current density at −200 mV, and a specific detectivity of 2.3 × 1012 Jones.