First-principles calculation of band offsets, optical bowings, and defects in CdS, CdSe, CdTe, and their alloys

Abstract

Using first principles band structure theory we have calculated (i) the alloy bowing coefficients, (ii) the alloy mixing enthalpies, and (iii) the interfacial valence band offsets for three Cd-based (CdS, CdSe, CdTe) compounds. We have also calculated defect formation energies and defect transition energy levels of Cd vacancy ${\mathrm{V}}_{\mathrm{Cd}}$ and ${\mathrm{Cu}}_{\mathrm{Cd}}$ substitutional defect in CdS and CdTe, as well as the isovalent defect ${\mathrm{Te}}_{\mathrm{S}}$ in CdS. The calculated results are compared with available experimental data.