Minority carrier lifetime in doped and undoped p-type Cd_xHg_1-xTe

Abstract

Photoconductive lifetime measurements have been carried out on thick samples of both doped and undoped slices of p-type CdxHg1-xTe prepared by Bridgman and accelerated crucible rotation (ACBT) Bridgman techniques. Means of reducing and/or allowing for surface recombination from front and back surfaces are described. The four recombination mechanisms though to be the most important in p-type material are outlined and compared to the experimental results. An analysis of lifetime versus temperature variations suggests that the Auger-7 recombination mechanism is not important for p-type material grown by the Bridgman technique. Measurements of lifetime in material covering a wide range of carrier concentration values confirms this view. An investigation of ZnS passivation on both n- and p-type material suggests that it can be a useful passivation for photovoltaic n-on-p devices.