Role of Argon in Optimization of the Cu Surface to Synthesize Uniform Monolayer Graphene by Chemical Vapor Deposition

Chemical vapor deposition is considered as one kind of most promising method to synthesize large-area monolayer graphene film. However, bilayer areas are usually observed on the monolayer graphene, which obviously influence the uniformity and decrease the mobility of graphene. In this work, high-quality and uniform monolayer graphene has been synthesized on the Cu foil. The studies reveal that the formation of multilayer graphene regions can be effetely prevented by replacing H-2 with Ar during the annealing process for Cu foil before the graphene growth. We expect the large area, monolayer graphene with high uniformity and quality will be widely used in graphene electronic devices and this study may be beneficial for the understanding of the growth mechanism for graphene on Cu surface.