Will a graphitic-like ZnO single-layer be an ideal substrate for graphene?

The interaction between graphene and substrates may destroy the intrinsic properties of graphene, and reduce the potential applications of graphene in electronic devices. Here, we use first-principles calculations to explore the possibility of a graphitic ZnO layer as an ideal substrate for graphene. Taking graphitic ZnO with and without oxygen vacancies, we found that the intrinsic linear dispersion of graphene is well retained. Additionally, the resultant bilayer structure of graphene and the graphitic ZnO layer shows much better optical properties compared with separate graphene and graphitic ZnO. Moreover, we also found that both the band dispersion and Fermi velocity of the bilayer structured graphene are robust towards an external electric field. Therefore, our results indicate that a graphitic ZnO layer may be a suitable substrate for graphene in real applications.