title: Metal-graphene interaction studied via atomic resolution scanning transmission electron microscopy.
abstract: Distributions and atomic sites of transition metals and gold on suspended graphene were investigated via high-resolution scanning transmission electron microscopy, especially using atomic resolution high angle dark field imaging. All metals, albeit as singular atoms or atom aggregates, reside in the omni-present hydrocarbon surface contamination; they do not form continuous films, but clusters or nanocrystals. No interaction was found between Au atoms and clean single-layer graphene surfaces, i.e., no Au atoms are retained on such surfaces. Au and also Fe atoms do, however, bond to clean few-layer graphene surfaces, where they assume T and B sites, respectively. Cr atoms were found to interact more strongly with clean monolayer graphene, they are possibly incorporated at graphene lattice imperfections and have been observed to catalyze dissociation of C-C bonds. This behavior might explain the observed high frequency of Cr-cluster nucleation, and the usefulness as wetting layer, for depositing electrical contacts on graphene.
authors.affiliation: School of Physics, The University of Manchester , Manchester, M13 9PL, United Kingdom.
authors.forename: Recep
authors.initials: R
authors.lastname: Zan
authors.forename: Ursel
authors.initials: U
authors.lastname: Bangert
authors.forename: Quentin
authors.initials: Q
authors.lastname: Ramasse
authors.forename: Konstantin S
authors.initials: KS
authors.lastname: Novoselov