Influence of Cu substrate topography on the growth morphology of chemical vapour deposited graphene

Raman spectroscopic maps were used to study the local properties of graphene films as grown on corrugated copper foils, by chemical vapour deposition, and after transfer onto SiO₂(300 nm)/Si substrates. Analysis of the Raman peaks show the films exhibit a striped periodic pattern of single- and bi-layer graphene. By performing simultaneous AFM-Raman line maps of the as grown film on Cu we find that the layer growth shows a strong correlation to substrate topography. As a result, compressively strained non-AB stacked bi-layer graphene forms preferentially along the ridges, whilst single-layer graphene grows inside the trenches, of the Cu foil topography. These experimental results suggest that surface mobility is not the dominating factor determining control of layer number in such growth regimes.