Influence of edge imperfections on the transport behavior of graphene nanomeshes

The electronic and transport properties of graphene nanomeshes (GNMs) were investigated using the density-functional theory and the non-equilibrium Green's function method. Our research indicates that the edge imperfections, such as edge roughness and edge doping, are of vital importance to the transport properties of GNMs. While the tunneling between the localized states caused by edge roughness would result in the metallic transport behavior of intrinsic GNMs, the experimentally observed semiconducting behavior could be explained by p-doping of GNMs with oxygen-containing groups. Furthermore, we found that the balance between the density of localized edge states and that of the edge O-doping is the key to the semiconductor behavior of GNMs. Unfortunately, the small density of edge states would lead to an ultra-low yield of semiconductor GNMs.