▎ 摘　　要

A photon-assisted CVD growth scheme of graphene using metal adatoms as catalysts it the edge of a graphene seed on noncatalytic surfaces, such as silicon dioxide (SiO2), hexagonal boron nitride (h-BN), and graphene, is reported based on first-principles calculations. We systematically examine the possible graphene edge reactions with carbon precursors such as methane, ethylene, or acetylene, using Cu and Ni adatoms as catalysts. The metal atoms adsorbed at the graphene edge capture the ambient ethylene or acetylene molecules, and initiate a series of edge reactions that would be energetically unfavorable in the absence of metal adatoms catalysts. We also suggest that ultraviolet photons can be used to dissociate the stable metal-ethylene or metal-acetylene complex in order to sustain the catalytic reactions. The growth rate of the graphene seed is shown to be slightly higher when on an h-BN or graphene substrate. In principle, this process could also be used to heal graphene defects between flakes or improve the continuity of I reduced graphene oxide films.