Bilayer graphene synthesis by plasma treatment of copper foils without using a carbon-containing gas

Bilayer graphene has been synthesized by using hydrogen plasma treatment of copper foils for 30 s at the temperature of 850 °C together with joule-heating treatment of the foils without using a carbon-containing gas such as methane in order to suppress the nucleation density of graphene. The effect of plasma provides active species of carbon atoms on copper substrate and a selective bilayer graphene formation of AB-stacking in a very short time. Carbon to be precipitated is delivered from the copper foil and/or the environment in the reaction chamber. The domain size of synthesized graphene, the controllability of a few layers and the electrical conductivity have been significantly improved compared with plasma chemical vapor deposition (CVD) using carbon-containing gas. The sheet resistance of bilayer graphene exhibits 951 Ω in average. The carrier mobility shows 1000 cm2/V s in maximum at room temperature. The sheet resistance of 130 ± 26 Ω has been attained after the doping by gold chloride solution.