Differences in the electronic structure and compensation mechanism between n-type An- and Cd-doped CuInS_2 crystals

摘要

We investigate the electronic structures of n-type CuInS_2 crystals in the chalcopyrite structure using An 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 CuInS_2 doped with An, compared with that for n-type CuInS_2 crystals doped with Cd species. For n-type CuInS_2 doped with An species, total energy calculations show that the formation of a Cu vacancy in the vicinity of a An 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.