Influence of copper crystal surface on the CVD growth of large area monolayer graphene

We study the influence of the surface structure of copper single crystals on the growth of large area monolayer graphene by chemical vapor deposition (CVD) in ultra-high vacuum (UHV). Using atomic-resolution scanning tunneling microscopy (STM), we find that graphene grows primarily in registry with the underlying copper lattice for both Cu(111) and Cu(100). The graphene has a hexagonal superstructure on Cu(111) with a significant electronic component,whereas it has a linear superstructure on Cu(100). Graphene on Cu(111) forms a microscopically uniform sheet, the quality of which is determined by the presence of grain boundaries where graphene grains with different orientations meet. Graphene grown on Cu(100) under similar conditions does not form a uniform sheet and instead displays exposed nanoscale edges. Our results indicate the importance of the copper crystal structure on the microstructure of graphene films produced by CVD.

Research highlights
► UHV growth of graphene by CVD.
► Structure of graphene grown on Cu(111) is significantly different from that grown on Cu(100).
► Graphene grows primarily in registry with the atomic lattices of Cu(111) and Cu(100).
► Graphene on Cu substrates has a strong electronic superstructure caused by interaction with the underlying metal.
► Graphene grown on these copper substrates is an electronically transparent yet chemically inert membrane that protects the surface.