Graphene on ordered Ni-alloy surfaces formed by metal (Sn, Al) intercalation between graphene/Ni(111)

Deposition and intercalation of Al and Sn on Ni(111) supported graphene is investigated by Auger electron spectroscopy, low energy electron diffraction, and scanning tunneling microscopy. Al intercalates at ~ 200 °C while Sn intercalates at ~ 350 °C, indicating that the intercalation process is element specific. Both Al and Sn alloy with the Ni-substrate at higher annealing temperatures and form ordered alloy surfaces and surface alloys, respectively. Sn forms a (√3 × √3) R30° surface alloy by substituting surface Ni-atoms with Sn and thus the alloy maintains the same good lattice match with graphene as for Ni(111). Both Sn and Al are interacting weakly with graphene and can therefore be used to decouple graphene from the strongly interacting Ni substrate.