The role of methane in the growth of bilayer graphene via chemical vapor deposition on copper foil
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1Chemical Enginnering Department, Tarbiat Modares University, Tehran, Iran
2Assistant Professor of Chemical Engineering, Nuclear Science and Technology Research Institute, Tehran, Iran
A controlled synthesis of high-quality bilayer graphene by chemical vapor deposition, has attracted enormous for use in a wide range of electronic and photonic devices. Although growth of graphene via chemical vapor deposition (CVD) on Cu substrate has limited with low coverage, uniformity and is facing self-limiting effect, but this method has been widely accepted as a promising approach to provide graphene in a repeatable, scalable and transferable manner. In this work, we demonstrated the effect of partial pressure of methane on the growth rate of bilayer graphene and the numbar of graphene layers for a various growth conditions. We can utilize a two-step growth process for controlling the nucleation and carbon delivery for bilayer graphene.It is accepted that the second layer is formed underneath the top-layer in according to adsorption-diffusion mechanism that dominates when a large portion of metal surface are exposed. Based on this mechanism,we find that concentration of CH4 and portion of availabled metal surface is critial for the formation of bilayer graphene in a low-pressure CVD process.