▎ 摘　　要

Epitaxial graphene by chemical vapor deposition (CVD) is one of the main meth-lids to fabricate high-quality wafer-scale graphene materials. However, CVD-grown graphene on metal substrates has some disadvantages, such as the need for a transfer process and carbon atoms dissolved into the metal substrate. In this work, we evaluate sapphire substrates to overcome those disadvantages. The morphology and crystal. quality of the samples grown at different temperatures were characterized by atomic force microscopy (AFM), optical microscopy (OM), Raman spectroscopy, and a Hall measurement system. To ease the etching process of carbon atoms to the substrate, we adopt a very low carbon concentration of 0.01%. AFM and Raman results show that the surface morphologies of samples grown at lower temperatures were smoother, whereas the quality of samples grown at higher temperatures was better. The sapphire substrate was etched in an H-2 environment, while it was not etched only by carbon source without H-2 environment. Epitaxial graphene with flat surface morphology and good crystal quality was prepared on a c-plane sapphire substrate (diameter: 50 mm) at a growth temperature of 1200 degrees C. The carrier mobility is above 1000 cm(2)-V-1.s(-1) at room temperature.