Control of valence states by a codoping method in CuInS 2

Abstract

We deviate the valence and conduction band energies of stoichiometric CuInS 2 crystals based on ab initio electronic band structure calculations using the augmented spherical wave (ASW) method and discuss that at low doping levels, the Madelung energy is a good intrinsic parameter for stabilization of p- or n-type doped CuInS 2 crystals. We find that P and Sb atoms are eminently suitable dopants substituted for S atoms for p-type doped CuInS 2 crystals with lower resistivity from both the character of electronic states around E F and the Madelung energy. A closer study of the nature of chemical bonds of CuInS 2 crystals using first-principles band structure calculation method reveals that In with polyvalence codoping for p-type CuInS 2 doped with P results in a decrease of the Madelung energy compared with CuInS 2: P, to be an effective method for stabilizing of its ionic charge distributions.