Controlled nucleation and growth of graphene: Competitive growth and etching in hydrogen diluted methane

摘要

Synthesis of graphene of large domain sizes in order to minimize scattering of charge carriers in grain boundaries is an essential process to be achieved before the full merits of graphene can be realized for next-generation nanoelectronics. Independent control of nucleation processes and growth processes in the complicated chemical vapor deposition environments is a key to achieving this goal. Catalyst assisted chemical vapor deposition of graphene on copper at around 1000°C near the melting point of copper in hydrogen diluted methane is fine tuned to reach dynamic balance between etching and growth of graphene. Surface diffusion of carbon atoms generated from methane and other hydrocarbon species, including those from etching graphene by atomic hydrogen, generated by the assistance of copper catalyst on the surface of copper foil results in complicated network of graphene domains separated by alley-like gaps of nearly equal width. By controlling the dynamic balance point, independent control of nucleation and growth and the synthesis of large individual graphene of various unique shapes and graphene films with networked alleys have been demonstrated.