▎ 摘　　要

Large-area epitaxial graphene films were grown on cobalt by thermal cracker enhanced gas source molecular beam epitaxy. Growth conditions including growth temperature and growth time play important roles in the resulting morphology of as-grown films. High-quality graphene films can be achieved in a small growth window. Fast cooling rate was not required in this process due to direct growth mechanism under atomic carbon growth condition. Large-area graphene films with high single-layer and bi-layer coverage of 93% were confirmed by Raman spectroscopy and transmission electron microscopy.