title: Slow gold adatom diffusion on graphene: effect of silicon dioxide and hexagonal boron nitride substrates.
abstract: We examine the nucleation kinetics of Au clusters on graphene and explore the relationship with layer number and underlying supporting substrate of graphene. Using the mean field theory of diffusion-limited aggregation, morphology patterns are semiquantitatively analyzed to obtain Au adatom effective diffusion constants and activation energies. Under specified assumptions, the Au adatom diffusion constant for single-layer graphene supported on SiO2 is ∼50 times smaller than that for hexagonal boron nitride (h-BN)-supported graphene and on the order of 800 times smaller than that for multilayer graphite. Bilayer graphene on SiO2 shows a Au adatom diffusion constant similar to single-layer graphene on h-BN. Scanning probe data show that single-layer graphene is far flatter on h-BN than on SiO2. Two factors are proposed as contributing to the observed lower diffusion constants on single-layer graphene: local surface roughness and homogeneous loss of dispersion/van der Waals electronic stability in multilayers. Graphene Raman spectroscopy shows little charge transfer between Au nanoparticles and graphene.
authors.affiliation: Department of Chemistry, Columbia University, New York, New York 10027, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.forename: Zheyuan
authors.initials: Z
authors.lastname: Chen
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Elena
authors.initials: E
authors.lastname: Polyakova Stolyarova
authors.forename: Takashi
authors.initials: T
authors.lastname: Taniguchi
authors.forename: Kenji
authors.initials: K
authors.lastname: Watanabe
authors.forename: James
authors.initials: J
authors.lastname: Hone
authors.forename: George W
authors.initials: GW
authors.lastname: Flynn
authors.forename: Louis E
authors.initials: LE
authors.lastname: Brus