The level of local charge-neutrality and pinning of the Fermi level in irradiated nitrides wz-III-N (BN, AlN, GaN, InN)

Abstract

On the basis of the density functional theory and general gradient approximation and the method of special points, the electronic spectra and the energy position of the local charge-neutrality level are calculated for the wurtzite BN, AlN, GaN, and InN compounds with the use of different heuristic models. It is shown that, with an increasing atomic mass of the cation in the wz-III-N compounds, the charge-neutrality level shifts from the position near the midgap in the BN and AlN, to the upper part of the band gap in GaN, and to the allowed energy region of the conduction band in InN. Such shifts define the semi-insulator properties of BN and AlN, the n-type conductivity of GaN, and the n+-type conductivity of InN on saturation of the wz-III-N compounds with intrinsic defects induced by high-energy irradiation.