the role of methane in the growth of bilayer graphene via chemical vapor deposition on copper foil

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#