Two-step growth of graphene with separate controlling nucleation and edge growth directly on SiO2 substrates

Recently, we have developed a catalyst-free and direct growth approach for nanographene on various substrates by a remote-plasma assisted chemical vapor deposition. A two-step growth strategy for separately controlling the nucleation and subsequent edge growth was further developed for growing graphene sheets with adjusted nuclei density and large domain size of 500 nm. The key for tuning the growth mode from nucleation to edge growth is the growth temperature; at a specific growth temperature (∼510–545 °C), only edge growth is available while the nucleation can be largely suppressed. This fine tuning of growth process yields a continuous polycrystalline graphene film with domain size of ∼150 nm. This domain size is controllable in this tunable growth to thus giving more freedom to control the graphene film properties.