First-principle study of vacancy-induced cubic boron nitride electronic structure and optical propertiy changes

Influences of vacancies on the electronic and optical properties of cubic boron nitride were investigated by using first-principles ultra-soft pseudopotential approach of the plane wave, based on the density functional theory. It was found that the formation of B vacancy is stable from the view of energy. Only the nearest atom were affected by vacancy, and the bandgap decreased from 6.3 eV to 2.86 eV or to 3.43 eV, by the introduction of 4.17% B or N vacancy . In addition, the boron vacancy also induce the emergence of an absorption band in the visible region, with the increase in vacancy concentration, the absorption in the visible region increased gradually, while the absorption in the ultraviolet region decreased.