▎ 摘　　要

NOVELTY - The modified chemical vapor deposition method for preparing uniform graphene material involves selecting semi-insulating silicon carbide substrate, cleaning the silicon carbide substrate, drying, placing into a chemical vapor deposition (CVD) apparatus, vacuumizing, turning on microwave power, heating, removing the gas adsorbed on a surface of the silicon carbide substrate, introducing hydrogen, heating, leaving still, removing the damage layer and scratches on the surface of the silicon carbide substrate, using argon gas and hydrogen as carrier gas, and filling argon gas. USE - Modified chemical vapor deposition method for preparing uniform graphene material. ADVANTAGE - The method enables modified chemical vapor deposition for preparing graphene material with flat and uniform surface. DETAILED DESCRIPTION - The modified chemical vapor deposition method for preparing uniform graphene material involves (1) selecting semi-insulating silicon carbide substrate, cleaning the silicon carbide substrate, and drying, (2) placing the cleaned silicon carbide substrate obtained in the step (1) into a chemical vapor deposition (CVD) apparatus, and vacuumizing to less than or equal to 10-4 mbar, (3) turning on microwave power, heating in vacuum environment, removing the gas adsorbed on a surface of the silicon carbide substrate, (4) introducing hydrogen at rate of 1-60 l/minute, where the gas pressure is 50-1000 mbar, heating at 1300-1600 degrees C, leaving still for 5-15 minutes, removing the damage layer and scratches on the surface of the silicon carbide substrate, (5) using argon gas and hydrogen as carrier gas, (6) filling argon gas, adjusting the flow rate of argon gas and hydrogen in carrier gas, controlling the partial pressure of argon gas in the carrier gas to more than 70%, introducing gaseous carbon source, where the flow rate of the gaseous carbon source is 0.001-10 l/minute, the ratio of flow rate of gaseous carbon source and hydrogen is controlled between 0.001-50%, adjusting the flow rate of argon gas and hydrogen gas in the carrier gas, controlling the partial pressure of hydrogen in the carrier gas to more than 70%, and introducing gaseous nitrogen source at flow rate of 0.001-2 l/minute, and (8) maintaining the nucleation and growth temperature at 1100-1900 degrees C and air pressure at 50-1000 mbar, where the nucleation phase time is 1-10 minutes and the growth phase time is 10-100 minutes, and forming 1-5 layers of P-type doped graphene on the surface of the silicon carbide substrate.