Group-IV and group-V substitutional impurities in cubic group-III nitrides -: art. no. 085209

We present ab initio pseudopotential plane-wave calculations for C, Si, Ge, P, As, and Sb on substitutional sites in cubic AlN and GaN for several charge states. The stability of these impurities, the geometry of the nearest neighbors, as well as the defect levels are studied in large supercells, reducing the impurity-impurity interaction and the alloying effect inherent the small supercells. Due to the large number of electrons in the supercell, higher charge states can be studied with less perturbation of the system. The trend of the defect levels and stability with respect to the atomic number of the impurity is analyzed in order to provide information about alternative dopants for the nitrides. Different growth and preparation conditions are considered. We estimate the partial concentrations of the incorporated impurities according to their charge states and versus the total amount of impurities available.