Insulating to metallic transition of an oxidized boron nitride nanosheet coating by tuning surface oxygen adsorption

Surface modification and functionalization are of fundamental importance in actual application of insulating coating, such as hexagon boron nitride (h-BN) nanosheet. Our first-principles calculations reveal that an oxidized h-BN monolayer supported by a Cu substrate exhibits metallic properties when O adatom vertically bonds with the B atom. This is mainly due to the hybridization of the p orbital of the BN layer and O adatom around the Fermi level. Charge transfer from the Cu substrate to the O atom stabilizes the formation of the vertical O-B bond. Injecting negative charges could trigger the migration of the O adatom from the B-N bond to B atom for metal or insulator-supported h-BN monolayer, which will lead to a metallic transition in the oxidized h-BN nanosheet. Our results provide a viable way to tune the electronic properties of surface h-BN coating through charge injection mediated O adsorption.