Chemical trends of defect formation and doping limit in II-VI semiconductors: The case of CdTe

Using first-principles band structure methods we studied the general chemical trends of defect formation in II-VI semiconductors. We systematically calculated the formation energies and transition energy levels of intrinsic and extrinsic defects and defect complexes in the prototype CdTe and investigated the limiting factors for p-type and n-type doping in this material. Possible approaches to significantly increase the doping limits are discussed. Our general understanding of the chemical trends of defect formation energies and transition energy levels in CdTe is expected to be applicable also to other II-VI semiconductors.