▎ 摘　　要

The growth of graphene by chemical vapor deposition on transition metal has shown promise in this regard. The main hurdle for further improvement is the lack of complete understanding of the atomistic processes involved in the early growth stages, which is conceivable because there are too many factors affecting the growth process. Using first-principles calculations, we investigate the effect of substrate defects on the graphene nucleation on the Ni(111) surface. Our calculations reveal that the defects on substrates can induce the carbon aggregation, and the corresponding structures are completely different from that on the perfect Ni surface. We also compare the critical cluster sizes for the transition from one-dimensional carbon chains to two-dimensional graphene flakes in the growth sequence. Our investigations on the effects of substrate defects would be extremely useful for the future experimental synthesis of high-quality graphene. (C) 2014 Elsevier B.V. All rights reserved.