Minority-carrier lifetime in doped and undoped n-type CdxHg1−xTe

Measurements of minority-carrier lifetime have been carried out on slices of n-type CdxHg1−xTe (0.2<x<0.3) prepared by both normal Bridgman and accelerated crucible rotation (ACRT) Bridgman techniques. Some of these crystals were deliberately doped with a high level of a single impurity. A study of aging effects has been concluded. Lifetime variations with temperature are explained using a combination of band-to-band and Shockley–Read recombination processes. Frequently, a single level 10–30 meV below the conduction-band edge was assumed, but for ACRT crystals it was necessary to postulate a second level. Attempts to identify the origin of the centers, by measurements on doped crystals, were only successful in the case of iron since it acts as a recombination center without providing conduction electrons in CdxHg1−xTe.