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

Kato, Ryuichi, Tsugawa, Kazuo, Okigawa, Yuki, Ishihara, Masatou, Yamada, Takatoshi, Hasegawa, Masataka
Carbon 2014 v.77 pp. 823-828
ambient temperature, chlorides, copper, electrical conductivity, foil, gold, graphene, hydrogen, methane, vapors
Bilayer graphene has been synthesized by using hydrogen plasma treatment of copper foils for 30s 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 951Ω in average. The carrier mobility shows 1000cm²/Vs in maximum at room temperature. The sheet resistance of 130±26Ω has been attained after the doping by gold chloride solution.