Sensitization of the minority-carrier lifetime in a photoconductor

Abstract

The effect of an increase of the majority-carrier lifetime, which follows the addition of rather than the elimination of recombination centers, has been known for years. In contrast, the corresponding effect for minority carriers has not been reported for any photoconductor, to the best of our knowledge. In this paper we present evidence for the latter effect in $n$-type $({\mathrm{Cu}}_{1\ensuremath{-}x}{\mathrm{In}}_{x}\mathrm{Se}{)}_{2}.$ It is shown that recombination centers, associated with the introduction of excess In, act as sensitizing centers for the minority carriers. The general importance of the effect for the spectroscopy of the electronic states in the forbidden band gap, and for device applications, are discussed.