Theoretical Insights into the Thermodynamics and Kinetics of Graphene Growth on Copper Surfaces

To control graphene growth on copper surfaces, we must understand the underlying growth mechanisms. Unfortunately, most high-resolution experimental characterization methods are not applicable under typical growth conditions, which makes theoretical simulations especially important in graphene growth mechanism studies. In this Feature Article, recent theoretical efforts in understanding graphene growth on copper surfaces are summarized. First-principles calculations indicate that methane decomposition on copper surfaces is very difficult. In contrast, dissociative adsorption of H₂ is exothermic and H adatom can reach an equilibrium with gas-phase hydrogen quickly. Although thermodynamic analysis is useful in estimating the concentrations of different C_xH_y species on the surface, reliable steady-state concentrations can only be obtained after the full kinetic network is constructed by kinetic Monte Carlo simulations or other methods, since graphene growth is a nonequilibrium process. With thermodynamic and kinetic insights provided by first-principles calculations and simulations, a unified picture can be obtained to understand graphene growth on Cu surfaces.