Compensation ofp-Type Doping in ZnSe: The Role of Impurity-Native Defect Complexes

We have examined the possibility that the saturation of the hole concentration observed in the $p$-type doping of ZnSe is caused by the formation of complexes between the substitutional acceptors and charged native defects such as Se vacancies and Zn interstitials. We present a simple model of compensation in which the relevant parameters are computed from first principles. A large lattice relaxation associated with the Se vacancy and the corresponding complex lowers their formation energy significantly. However, the large binding energy of the acceptor-Zn-interstitial complex should make it a more efficient compensator. Under typical growth conditions, our model reproduces the experimentally observed saturation of the hole concentration in the ${10}^{18}$ ${\mathrm{cm}}^{-3\mathrm{}}$ range.