▎ 摘　　要

Growth of epitaxial graphene (EG) on silicon carbide (SiC) is regarded as one of the most effective routes to high-quality graphene towards practical applicability. We try to build up a model to illuminate the nucleation process of EG on SiC by thermal decomposition. The model is derived from some experimental results and discloses that surface diffusion plays an important role in the nucleation. For the chemical vapor deposition process used, the organic gas as carbon precursor enables carbon deposition quickly for supporting the growth of high-quality graphene via vapor transformation, so that the nucleated and final graphene becomes almost stress-free and mimics the free-standing graphene. Our findings have a potential in preparing high-quality graphene by controlling the nucleation conditions.