Thermodynamics and Kinetics of Graphene Growth on Ni(111) and the Origin of Triangular Shaped Graphene Islands

To understand the origin of the triangular shaped graphene, we systematically investigated the thermodynamics and kinetics of graphene growth on Ni(111) surface. It was found that the fcc staking of graphene on the substrate is more energetically favorable than other stacking sequences. Under the near thermoequilibrium condition, a graphene island will present a truncated triangular shape with alternative zigzag (ZZ) and ZZKlein edges; its growth is either on the top of the terrace (on-top mode) or embedded into the metal lattice (inlay mode). If the growth process is controlled by kinetics of carbon atom incorporation, the shape of a graphene island will be triangular because of the significant growth rate difference between the ZZ and ZZ-Klein edges. This study reveals the atomic details of graphene growth on Ni(111) surface, and the deep insights into the mechanism of graphene CVD growth may lead to the rational design of experiments for the growth of desired graphene and other 2D materials.