Quasi-Free-Standing Epitaxial Graphene on SiC (0001) by Fluorine Intercalation from a Molecular Source

We demonstrated a novel method to obtain charge neutral quasi-free-standing graphene on SIC (0001) from the buffer layer using fluorine from a molecular source, fluorinated fullerene (C60F48). The intercalated product is stable under ambient conditions and resistant to elevated temperatures of up to 1200 degrees C. Sunning tunneling microscopy and spectroscopy measurements are performed for the first time on such quasi-free-standing graphene to elucidate changes in the electronic and structural properties of both the graphene and interfacial layer. Novel structures due to a highly localized perturbation caused by the presence of adsorbed fluorine were produced in the intercalation process and investigated. Photoemission spectroscopy is used to confirm these electronic and structural changes.