▎ 摘　　要

NOVELTY - The preparation of single layer polycrystalline graphene film, involves (1) annealing metal substrate using chemical vapor deposition technology in the presence of hydrogen, and catalytically cracking carbon source gas with large gas flow on the surface of metal substrate at high temperature, and controlling the gas flow rate greater than or equal to 20 sccm, and growing graphene film, (2) changing the growth atmosphere to inert gas, etching the surface layer of graphene, using small amount of hydrogen to precipitate carbon atoms dissolved in interior of the substrate to surface of the substrate, forming graphene crystal nucleus with adjustable density, (3) introducing carbon source gas to regenerate surface of graphene nucleus to obtain polycrystalline graphene film and adjusting grain size of graphene film to form uniform controllable grain size. USE - Preparation of single layer polycrystalline graphene film used for nano-electronic device, optoelectronic device, photonic device, gas sensor and thin film electronic device. ADVANTAGE - The method enables preparation of single layer polycrystalline graphene film ensuring high quality by simple process.