First-Principles Study of Doping Limits of CdTe

First-principles total energy and band structure calculations are performed to understand the factors that limit doping in CdTe. We calculated systematically the formation energies and transition energy levels of intrinsic and extrinsic defects and defect complexes. We find that n-type doping in CdTe is limited by the spontaneous formation of the intrinsic closed-shell cation vacancy VCd2— and/or DX centers. For p-type doping, it is limited by not having a dopant with both high solubility and shallow acceptor level.