Control of valence states by a codoping method in CuInS2

We deviate the valence and conduction band energies of stoichiometric CuInS2 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 isa good intrinsic parameter for stabilization of p-or n-type doped CuInS2 crystals. We find that P and Sb atoms are eminently suitable dopants substituted for S atoms for p-type doped CuInS2 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 CuInS2 crystals using first-principles band structure calculation method reveals that In with polyvalence codoping for p-type CuInS2 doped with P results in a decrease of the Madelung energy compared with CuIrS2:P, to be an effective method for stabilizing of its ionic charge distributions.