Growth mechanisms and selectivity for graphene or carbon nanotube formation on SiC (): A density-functional tight-binding molecular dynamics study

We have performed density-functional tight-binding simulations mimicking the thermal decomposition of the SiC ( 0 0 0 1 ¯ ) surface to reproduce the experimentally observed growth of either graphene or carbon nanotubes. A graphene-like network was obtained from a layer-by-layer decomposition of the SiC surface. The interaction between graphene and SiC was found to be relatively weak. Meanwhile, carbon nanotubes grew when a five-membered ring was initially formed together with a carbon chain. The simulation results suggest that growth selectivity depends on the overall carbon network connectivity and carbon aggregation speed at the very initial stage of the decomposition process.