The electronic structures of B and N vacancies in the cubic nitride were investigated by using the full-potential linearized augmented plane-wave, full-potential linear muffin-tin orbital, and linear muffin tin orbital tight-binding approaches. It was found that all of the methods gave quantitatively consistent results for the ideal cubic nitride. By using a 64-atom super-cell, a study was made of the electronic states of B and N vacancies. Lattice relaxation around the vacancies was not considered. Both B and N defect states appeared to form well-defined narrow bands in the forbidden gap of crystalline material. Those for the B vacancy were located near to the top of the valence band, and were partially occupied. They represented so-called acceptor levels of the B vacancy. In the case of the N defect, the so-called vacancy levels overlapped with the states at the conduction-band edge. The characteristics of vacancy states, their degree of localization and effect upon the electronic density of states, and the charge distribution in crystals, were considered. The results suggested that B and N vacancies could be thought of as being p-type and n-type doping agents, respectively, when the composition deviated from the ideal stoichiometry.

V.A.Gubanov, Z.W.Lu, B.M.Klein, C.Y.Fong: Physical Review B, 1996, 53[8], 4377-85