Minority carrier sweepout effects in HgCdTe infrared photoconductors at temperatures above 80K

Abstract

The effect of drift and diffusion of minority carriers into regions of high recombination which occur at the metal/semiconductor interface of contacts, has the effect of reducing the density of photogenerated excess carriers in photoconductive devices. This loss of photogenerated carriers, which is enhanced at higher applied electric fields, is known as minority carrier sweepout, and is an important mechanism that limits the performance of HgCdTe photoconductive devices operating at high bias fields. In this study, experimentally determined contact recombination velocities range from 25 cm/s at 80 K, to 600 cm/s at 200 K for x=0.31 Hg/sub 1-x/Cd/sub x/Te. Hence, it is concluded that contact recombination is a dominant mechanism at higher temperatures even though it may not be significant at 80 K.