Size-Selective Carbon Nanoclusters as Precursors to the Growth of Epitaxial Graphene

摘要: The nucleation and growth mechanisms of graphene on Rh(111) via temperature-programmed C2H4 are studied by scanning tunneling microscopy spectroscopy, density functional theory calculations. By combining our experimental first-principles approaches, we show that carbon nanoislands form in the initial stages growth, possessing an exclusive size seven honeycomb units (hereafter labeled as 7C6). These clusters adopt a domelike hexagonal shape indicating bonding to substrate is localized peripheral C atoms. Smoluchowski ripening identified dominant mechanism leading formation graphene, with size-selective islands precursors. Control experiments calculations, whereby coronene molecules, hydrogenated analogues 7C6, deposited Rh(111), provide unambiguous structural chemical identification 7C6 building blocks.