Synthesis of Multilayer Graphene with Controlled C Supply

Because of the very low C solubility, Cu substrates possess a great advantage in growing the graphene film of monolayer or few layers with well‐developed uniformity. The self‐limited growth manner ensures the growth of nearly pure monolayer graphene, but it prevents the supply of C for the growth of adlayers after the complete growth of the top layer. Herein, a method to continuously supply C from one side of Cu substrate while maintaining sustained growth of multilayer graphene on the other side by separately controlling the atmosphere on two sides is studied. The growth rate and thickness of graphene can be controlled by tuning the oxygen flow and postgrowth time. Multilayer graphene with thickness (t) up to 100 nm is achieved. It demonstrates a potential application in terahertz shielding with a high shielding effectiveness (SE) of 25 dB and accordingly a high SE/t of 2.5 × 105 dB/mm. The study contributes to the controllable growth of graphene films in terms of layer numbers and can be scaled up to large‐area growth through the appropriate design of equipment. A method to continuously supply carbon from one side of Cu substrate while maintaining a sustained growth of multilayer graphene on the other side by separately controlling the atmosphere on the two sides is provided. The study contributes to the controllable growth of graphene films in terms of layer numbers.