Hybrid functional with semi-empirical van der Waals study of native defects in hexagonal BN

The formation energies and transition energy levels of native defects in hexagonal BN have been studied by first-principles calculations based on hybrid density functional theory (DFT) together with an empirical dispersion correction of Grimmeʹs DFT-D2 method. Our calculated results predict that the interstitial B is the most stable defect under N-rich and p-type conditions. While the B vacancy and interstitial N become the dominate defects when the electron chemical potential is near the conduction band maximum of host. Nevertheless, these compensating defects would be inactive due to their ultra deep ionization levels under both p- and n-type conditions.