Epitaxial growth of a graphene single crystal on the Ni(111) surface

The thermally controlled synthesis of graphene from propylene molecules on the Ni(111) surface in ultrahigh vacuum is studied by scanning tunneling microscopy and density functional theory. It is established that the adsorption of propylene on Ni(111) atomic terraces at room temperature results in the dehydration of propylene molecules with the formation of single-atomic carbon chains and in the complete dissociation of propylene at the edges of atomic steps with the subsequent diffusion of carbon atoms below the surface. The annealing of such a sample at 500$^\circ$ C leads to the formation of multilayer graphene islands both from surface atomic chains and by the segregation of carbon atoms collected in the upper nickel atomic layers. The process of formation of an epitaxial graphene monolayer until the complete filling of the nickel surface is controllably observed. Atomic defects seen on the graphene surface are interpreted as individual nickel atoms incorporated into graphene mono- or bivacancies.