Study of Cooling Rate on the Growth of Graphene via Chemical Vapor Deposition

The chemical vapor deposition (CVD) technique has become one of the most widely used methods in the synthesis/study of graphene owing to its capability in large-area and uniform synthesis with great potential in mass production. It is also well-known that single-layer graphene can be grown on copper-based catalytic substrates due to its low carbon solubility. However, few layer graphene patches are typically generated at grain boundaries or defect sites in the metal substrate, which lowers the overall qualities of graphene film. Various factors, often closely correlated, influence the CVD process, and thus the properties of graphene. In this work, we provide detailed analysis on the cooling rate in the CVD process and its effect on the general properties of graphene. Various configurations of cooling conditions, controlled by the speed of cooling rate, were examined. Its effects on several physical properties were investigated, and it is found that the cooling rate plays an important role in producing high-quality single-layer graphene. On the basis of our observations, synthesis of high quality, continuous, single-layer graphene with negligible few-layer patches can be successfully accomplished, which can promote the widespread industrial applications of CVD graphene.