Point vacancy defects in hexagonal boron nitride studied by first-principles

Abstract

Point vacancy defects in hexagonal boron nitride (h-BN) were investigated by first-principles calculations based on the generalized gradient approximation method in the density-functional theory. The obtained formation energies of B vacancy (V_B) and N vacancy (V_N) with different charge states suggest that is stable for p-type h-BN in both N-rich and N-poor growth conditions, while is stable for n-type h-BN in both N-rich and N-poor growth conditions. Positron lifetime calculations were also carried out on h-BN using the atomic superposition method. The calculated positron bulk lifetime of h-BN was 180.6 ps, positron lifetime of V_B was 183.6 ps, and positron lifetime of V_N was 181.5 ps. The positron lifetime difference is small, but the tendency is clear, showing that .