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

We investigate the electronic structures of n-type CuInS2 crystals in the c halcopyrite structure using Zn or Cd species, Cu-substituting species, as d onor dopants, based on the results of ab initio electronic band structure c alculations. We find the strongly localized impurity states for n-type CuIn S2 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 calculati ons show that the formation of a Cu vacancy in the vicinity of a Zn site, d onor-impurity site, is energetically more favorable. From these findings fo r the electronic structure and the compensation mechanism, we predict that Cd species can be considered as suitable candidates for use as donor dopant s. (C) 1999 Elsevier Science B.V. All rights reserved.