Low Partial Pressure Chemical Vapor Deposition of Graphene on Copper

A systematic study of the Cu-catalyzed chemical vapor deposition of graphene under extremely low partial pressure is carried out. A carbon precursor supply of justPCH_4~0.009 mbar during the deposition favors the formation of large-area uniform monolayer graphene verified by Raman spectra. A dilutedHNO₃solution is used to remove Cu before transferring graphene onto SiO₂/Si substrates or carbon grids. The graphene can be made suspended over a~12μm distance, indicating its good mechanical properties. Electron transport measurements show the graphene sheet resistance of~0.6kΩ /at zero gate voltage. The mobilities of electrons and holes are~1800 cm²/Vs at 4.2 K and~1200 cm²/Vs at room temperature.