Electron beam-induced formation and displacement of metal clusters on graphene, carbon nanotubes and amorphous carbon

Nanocrystals of different metals with sizes of 2–6 nm are deposited on graphene, carbon nanotubes, or amorphous carbon films. Irradiation with a highly focused electron beam is used to split clusters of a few metal atoms (<1 nm in diameter) from the crystals. The metal clusters follow the electron beam spot on the graphitic surface when the beam is slowly deflected away from the clusters. This unusual behaviour of metals on graphitic surfaces is explained in terms of electron beam-induced activation of the graphitic surfaces and covalent bonding between metal and carbon atoms. The technique might be applicable in (sub-)nanometre structuring of graphene with metal dots.