▎ 摘　　要

The growth process of graphene structure on 6H-SiC(0001) surface has been studied using the classical molecular dynamics simulation and the simulated annealing technique. Effects of annealing temperature and coverage of carbon atoms on the formation of graphene have been investigated. We found that two layers of carbon atoms of the 6H-SiC(0001) subsurface after sublimation of Si atoms undergo a transformation from a diamondlike phase to a graphenelike structure at annealing temperature above 1500 K. This transformation temperature is in good agreement with experimental observations. We also found that the formation of graphene structure strongly depends on the number of carbon layers. Two layers of carbon atoms result in large graphene clusters and four layers of carbon lead to the formation of graphene bilayer sheets. However, a single layer of carbon only forms chainlike and ringlike clusters without the hexagonal ordering. Our results provide atomic-level information about the graphitization of the 6H-SiC(0001) surface, which is useful in controlling the growth of graphene sheets. (C) 2008 American Institute of Physics.