We review the development of synthesis technique of highly-electrically conductive graphene by plasma assisted chemical vapor deposition (CVD). Plasma exposure enhances the decomposition of the carbon source gas such as methane and the activation by the catalyst, resulting in a high growth rate of the graphene. If the carbon concentration is high the nucleation density on the metal catalyst is increased, resulting in a smaller domain size. For plasma CVD, the carbon concentration should be much lower than that for thermal CVD. Decreasing the carbon concentration during the graphene synthesis, which is expected to suppress the nucleation density, is one way to expand the size of the graphene crystals and to improve the controllability of a few layers. We developed the synthesis method of graphene by plasma CVD with very low carbon-source concentrations to improve the crystalline quality and the electrical properties of graphene transparent conductive films. The carrier mobility of more than 1000 cm2/Vs and the sheet resistance of less than 150 Ω for bilayer graphene have been attained. We have demonstrated superior flexibility of graphene transparent conductive films and demonstrated some flexible devices. This paper is partially based on results obtained from a project supported by New Energy and Industrial Technology Development Organization (NEDO).

We review the development of synthesis technique of highly-electrically conductive graphene by plasma assisted chemical vapor deposition (CVD). Plasma exposure enhances the decomposition of the carbon source gas such as methane and the activation by the catalyst, resulting in a high growth rate of the graphene. If the carbon concentration is high the nucleation density on the metal catalyst is increased, resulting in a smaller domain size. For plasma CVD, the carbon concentration should be much lower than that for thermal CVD. Decreasing the carbon concentration during the graphene synthesis, which is expected to suppress the nucleation density, is one way to expand the size of the graphene crystals and to improve the controllability of a few layers. We developed the synthesis method of graphene by plasma CVD with very low carbon-source concentrations to improve the crystalline quality and the electrical properties of graphene transparent conductive films. The carrier mobility of more than 1000 cm2/Vs and the sheet resistance of less than 150 Ω for bilayer graphene have been attained. We have demonstrated superior flexibility of graphene transparent conductive films and demonstrated some flexible devices. This paper is partially based on results obtained from a project supported by New Energy and Industrial Technology Development Organization (NEDO).