The excess carrier lifetime in p-type HgCdTe measured by photoconductive decay

Abstract

The excess carrier lifetime has been measured in p-type Hg1−xCdxTe, with x=0.225 and p∼1×1016/cm3 , using the technique of photoconductive decay. Measurements as a function of temperature were carried out on bulk vacancy-doped crystals grown by three different techniques, as obtained from four independent sources. The lifetimes at 77 K were found to vary between 23 and 100 ns, and were correlated with the inverse carrier concentration. We present simple theoretical arguments which show that the lifetime can, in certain cases, be limited by recombination at the 15-meV acceptor level. By considering this recombination mechanism, as well as recombination at deeper levels, we were able to model all our data and derive the dependence of lifetime on the doping level.