The effect of growth condition on graphene growth via Cu-assisted plasma reduction and restoration of graphene oxide

Graphene, a monolayer sheet of graphite, shows plenty of attractive properties and has been expected to replace conventional materials in various fields. For the industrial application of graphene, a high throughput synthesis method on arbitrary substrates is strongly required. Chemical exfoliation via graphene oxide (GO) is thought to be a suitable method for the high throughput synthesis. However, the crystallinity of reduced GO is unacceptably low. Although we found that the plasma treatment with Cu catalyst yields graphene with high crystallinity from GO on a dielectric substrate, the effect of the growth parameter has been unclear. Here, we investigated the effect of the gas ratio of CH ₄ and H ₂ in this process on the crystallinity of graphene. By optimizing the gas ratio, we succeeded in reducing and restoring GO to the extent that its mobility increased to 9.0 × 10 ² cm ² V ^-1 s ^-1 .