▎ 摘　　要

Graphene thin films were epitaxial grown on Si(111) substrates by depositing carbon atoms with solid source molecular beam epitaxy (SSMBE). The structural properties of the samples deposited at different substrate temperature (400, 600, 700 and 800 degrees C) were investigated by reflection high energy electron diffraction (RHEED), Fourier transform infrared spectroscope (FTIR), Raman spectroscope (RAMAN) and near-edge X-ray absorption fine-structure (NEXAFS). RAMAN and NEXAFS results indicated that the thin film deposited at 800 degrees C exhibited the characteristic of graphene, while the thin films deposited at 400 degrees C, 600 degrees C and 700 degrees C were attributed to amorphous or polycrystalline carbon thin films. RHEED and FTIR results indicated that C atoms did not bond with Si atoms at the substrate temperature below 600 degrees C, however, above 700 degrees C, C atoms reacted with Si atoms and formed the SiC buffer layer. Furthermore, the better quality of SiC buffer layer could be obtained at 800 degrees C. Thus, high substrate temperature and high-quality SiC buffer layers are essential to the formation of the graphene layers on the Si substrates.