Carrier lifetime in HgTe/CdTe superlattices grown by photoassisted molecular beam epitaxy

Abstract

We report excess carrier lifetimes of several hundred nanoseconds in HgTe/CdTe superlattices grown by photoassisted molecular beam epitaxy. The structures were doped either n-type in the low 1015 cm−3 range or p-type in the low 1016 cm−3 range, and were designed for peak response in the long-wave infrared regime. The measured lifetimes, recorded by the transient photoconductivity technique, approach values calculated for alloys of equivalent band-gap energy. They indicate that recombination at the superlattice interfaces has been substantially reduced and underscore the recent progress achieved in superlattice growth technology.