Differences in the electronic structure and compensation mechanism between n-type Zn- and Cd-doped CuInS2 crystals

Abstract

We investigate the electronic structures of n-type CuInS2 crystals in the chalcopyrite structure using Zn or Cd species, Cu-substituting species, as donor dopants, based on the results of ab initio electronic band structure calculations. We find the strongly localized impurity states for n-type CuInS2 doped with Zn, compared with that for n-type CuInS2 crystals doped with Cd species. For n-type CuInS2 doped with Zn species, total energy calculations show that the formation of a Cu vacancy in the vicinity of a Zn site, donor-impurity site, is energetically more favorable. From these findings for the electronic structure and the compensation mechanism, we predict that Cd species can be considered as suitable candidates for use as donor dopants.