AVS 57th International Symposium & Exhibition
    Graphene Focus Topic Tuesday Sessions
       Session GR+TF-TuA

Paper GR+TF-TuA11
Stability of Continuous Graphene Sheet and Graphene Flake on the Si(111) Surface

Tuesday, October 19, 2010, 5:20 pm, Room Brazos

Session: Graphene and 2D Nanostructures
Presenter: B.B. Kappes, Colorado School of Mines
Authors: B.B. Kappes, Colorado School of Mines
T.E. Davies, Colorado School of Mines
S. Jun, University of Wyoming
A.C.T. van Duin, Penn State University
C.V. Ciobanu, Colorado School of Mines
Correspondent: Click to Email
While rapid use of carbon nanostructures in the silicon-based nanoelectronics industry will involve the direct integration of graphene with silicon chips, so far graphene has not been grown on pristine silicon surfaces because usual synthesis routes would likely lead to the formation of stable silicon carbide instead of the precipitation of carbon at the surface. Here we show that if graphene can be deposited on pristine Si(111) surfaces, then it forms moiré superstructures and binds strongly to the substrate over a wide range of in-plane orientations. The binding energies depend on the orientation of graphene as well as the strain applied to achieve commensurability with the substrate; the strongest binding estimated from density functional theory calculations is approximately 1.5 eV/carbon atom. Using molecular dynamics simulations based on bond-order and reactive force field interatomic potentials, we present evidence that graphene remains stable and bonded to the substrate for temperatures up to 80% of the substrate melting temperature. Bonding information, study of the local density of states, and simulated scanning tunneling microscopy show graphene on Si(111) is semiconducting, with a sizable number of carbon hybridized sp3 and a bandgap affected by the orientation of graphene with respect to the substrate.