Electronic and transport gaps of graphene opened by grain boundaries

Abstract

The electronic and transport properties of graphene grain boundaries (GBs) are studied using density functional theory and nonequilibrium Green's function method. Most GBs preserve the semi-metal properties of perfect graphene; however, some GBs can open a moderate band gap up to 0.5 eV, which provides a potential way for band engineering of graphene-based materials. Nonequilibrium calculations of transmission coefficients showed that the conduction channels for transport electrons at Fermi level can be totally blocked or reduced due to existence of GBs. Moreover, the detailed defect arrangements have some influence on the transport behavior of graphene GBs.