Surface diffusion coefficient of Au atoms on single layer graphene grown on Cu

A 5 nm thick Au film was deposited on single layer graphene sheets grown on Cu. By thermal processes the dewetting phenomenon of the Au film on the graphene was induced so to form Au nanoparticles. The mean radius, surface-to-surface distance, and surface density evolution of the nanoparticles on the graphene sheets as a function of the annealing temperature were quantified by scanning electron microscopy analyses. These quantitative data were analyzed within the classical mean-field nucleation theory so to obtain the temperature-dependent Au atoms surface diffusion coefficient on graphene: D_S (T)=[(8.2±0.6)×〖10〗^(-8) ]exp⁡[-(0.31±0.02 eV/at)/kT] 〖cm〗^2/s.