Generation recombination suppression via depletion engineered heterojunction for alternative substrate MWIR HgCdTe infrared photodetectors

Abstract

We show suppression of generation-recombination dark current that leads to an increase in the operating temperature nearly 40 K (from ∼85 K to ∼125 K, τSRH = 200 ns) with diffusion limited performance of alternative substrate multiwafer infrared HgCdTe infrared photodetectors with a cut-off wavelength of 5 μm. Enhancement has been achieved by shifting the depletion region into an n type wide bandgap material. An in-house numerical model, which solves Poisson, continuity, and current equations for electrons and holes, is utilized for high precision in electrical and optical characterization of the detector. Composition and doping levels are optimized so that the collection of photo-generated carriers is not disturbed and the quantum efficiency is kept high.