On the Role of Metal Step-Edges in Graphene Growth

Abstract

Graphene growth on transition metal surfaces is studied by means of density functional theory calculations. The results show that graphene grows preferentially out from surface step edges onto lower facets on fcc and hcp metal surfaces. The results also reveal that an epitaxial lattice match between graphene and the metal step-edge stabilizes graphene and lowers the corresponding critical graphene nucleus size. In the case of a graphene−metal lattice mismatch, a destabilization of the critical graphene nucleus size may be compensated by tuning the carbon chemical potential. The concepts of metal−graphene lattice and carbon chemical potential are included in a simple growth model that describes experimental trends in graphene formation at different metal surfaces under varying growth conditions.