First-principles study of native and extrinsic point defects in cubic boron nitride

Using first-principles total energy methods, we systematically calculated the formation energies and transition energy levels of intrinsic and extrinsic defects in cubic boron nitride (c-BN). We employed a mixed k-point sampling approach and brought the band-gap error into consideration. We find that under B-rich conditions boron vacancy (VB) and nitrogen vacancy (VN) act as the dominant compensating centers for additional dopants, while at N-rich limits, boron antisite (NB) becomes the main acceptor 'killer'. The result is inaccessible if the impact of band-gap correction on the formation energies is ignored. Besides, all the calculated defect levels are too deep to account for the observed n- or p-type conductivity in as-grown samples. Among all the attempted dopants, substitutional Be (BeB) is the desirable acceptor in terms of lower formation energy and energy levels under N-rich conditions. However, n-type c-BN seems difficult to obtain under equilibrium conditions, because of the low solubility of dopants and the abundance of the compensating center VB3−.