Controlling the self-doping of epitaxial graphene on SiC via Ar ion treatment

We present a simple but efficient way to control substrate-induced doping of graphene via mechanical deformations induced by Ar ions. Graphene on SiC is n-doped because of the substrate-to-graphene charge transfer. Using angle-resolved photoemission spectroscopy (ARPES), core level shift, and scanning tunneling microscopy (STM), the treatment with 0.5-keV Ar ions was found to reduce the charge transfer. First-principles calculations suggest that Stone-Wales defects among various defect structures are likely responsible for the change in the substrate-graphene charge transfer.