Electronic properties of graphene on the C-decorated Si(111) surface: An ab initio study

First principles calculations based on the density functional theory are performed to study electronic structures of graphene adsorbed on clean or C-decorated Si(111) surface. Two types of surface reconstructions, 2 × 2 and 3×3, are considered to be decorated by carbon atoms with different concentrations. We find that graphene adsorbed on ideal clean Si(111) surface tends to induce a 2 × 1 reconstruction, and its electronic dispersion characteristics are preserved. Moreover, the decoration of carbon atoms on the Si(111) surface can effectively passivate the Si dangling bonds on the surface. Such decoration effects make the carbon decorated Si(111) surfaces promising substrate for graphene preserving its excellent electronic structure.