Spectromicroscopy of single and multilayer graphene supported by a weakly interacting substrate

We report measurements of the electronic structure and surface morphology of exfoliated graphene on an insulating substrate using angle-resolved photoemission and low-energy electron diffraction. Our results show that, although exfoliated graphene is microscopically corrugated, the valence band retains a massless fermionic dispersion with a Fermi velocity of ~10⁶ m/s. We observe a close relationship between the morphology and electronic structure, which suggests that controlling the interaction between graphene and the supporting substrate is essential for graphene device applications.