ELECTRONIC-ENERGY STRUCTURE OF NONSTOICHIOMETRIC CUBIC BORON-NITRIDE

In terms of the multiple-scattering theory using the cluster version o f the local coherent-potential approximation the electronic energy str uctures of both stoichiometric and non-nonstoichiometric cubic boron n itride have been calculated. It was found that vacancies induced in th e sublattice of nitrogen in boron nitride resulted in a marked change in the nitrogen p-band, in a noticeable low-energy shift of the total density of electron states of the valence band and in the appearance o f additional acceptor energy levels in the region of forbidden energie s. The latter explains the twofold increase in the electrical conducti vity of non-stoichiometric boron nitride in comparison with stoichiome tric boron nitride found experimentally and calculated in the present work. The calculated partial and total densities of electron states of boron nitride have been used to explain the form of its experimental x-ray emission and x-ray photoelectron spectra.