Auger-limited carrier lifetimes in HgCdTe at high excess carrier concentrations

Abstract

The performance of n-type Hg0.8Cd0.2Te (PC) detectors under high optical flux densities was investigated. Detector photoconductivity and response time were measured, in the presence of 10.6-μm laser radiation. Flux densities, φ, were varied over four orders of magnitude up to a maximum level of φ=1021 photons/cm2 sec. For high flux levels the photoconductivity varies as the cube root of the incident flux and the detector response time varies as φ−2/3. It is concluded that the observed saturation in photoconductivity is due to the decrease in carrier lifetime with carrier concentration. The dominant recombination mechanism at high flux levels was determined to be Auger recombination.