▎ 摘　　要

Graphene has aroused great interest because of its peculiar band structure and excellent physical properties. But today, the development of graphene is limited to its size and quality. In this paper, single- and multilayer graphene films are synthesized on copper foils by chemical vapor deposition (CVD) using methane at ambient pressure. Experimental results find that the high temperature, low concentration of methane gas, shorter growth time and suitable gas flow are the key to obtaing the high-quality and large-scale graphene films. Raman spectra, scanning electron microscope and transmission electron microscope characterization indicate the graphene films are mostly of single-layer structure, only a few of multilayer graphene films are observed around the copper boundaries. Further electrical tests show that the graphene films grown by CVD method represent semiconductor behavior under low temperature and the sheet resistances of graphene films decrease with the external magnetic field increasing.