Direct or indirect semiconductor: The role of stacking fault in h-BN

Electronic properties of hexagonal boron nitride (h-BN) with stacking fault have been systematically studied using the first-principles method. The formation energy of a single layer stacking fault in five typical stacking h-BN (AA, AB, AD, AE and AF) ranges from −58 to 55 meV, which indicates that the stacking fault can be easily introduced into the material. Amazingly, we find that as long as AA, AB, AD and AF stacking h-BN with AE-liked stacking fault they are similar to AE stacking with or without stacking fault behaving as quasi-direct or direct semiconductor. We predict that the AE-liked stacking sequence may be the primary reason for the inconsistency between theoretical and experimental reports according to the type of the band gap of h-BN.