Copper Vapor Catalyzing Role in the Growth of Graphene.

Cu is the most used substrate to grow monolayer graphene under a temperature near the melting point. In this study, we elaborated a remarkable amount of Cu clusters were continuously evaporated during the graphene growth, resulting in the vapor pressure comparable with the CH₄. Importantly, the decomposition barrier of CH₄ on Cu clusters is similar to or even lower than that on the Cu surface. CuCH₄ serves as the primary active cluster in complex intermediates, exhibiting a growth-promoting effect. Particularly after the first graphene layer coverage, it may emerge as a dominant catalytic factor for multilayer growth by supplying critical growth species. Through controlled seed incorporation, this mechanism is expected to enable large-area controllable growth of bilayer and multilayer graphene structures.