Band gaps of graphene on layered ZnO substrate: A first principles study

Abstract

Using density functional theory, we show that the band gap of graphene can be induced via deposition on a layered ZnO substrate. This phenomenon can be understood based on the symmetry-breaking substrate potential, which leads to the nonequivalence of sublattices in graphene. With the decrease of interlayer spacing, the band gap of graphene was improved, while the electron effective mass (EEM) increases and the carrier mobility decreases. The finding of large Fermi velocity, which is comparable to that of an isolated graphene, retards the increase of EEM with the band gap, and thus, provides a possible way to design the graphene-based field-effect transistors.