Effect of interfacial layer on graphene structure in-situ grown on cemented carbide

In-situ spheroidal graphene film (SGF) may be a hopeful candidate of sensor matrix for space exploration. A poor understanding of the influence of interfacial layer on graphene structure restricts its benefit fulfillment. In this work, the SGF was in-situ grown on a cemented carbide substrate, and its influence on the graphene structure was investigated. An amorphous silicon carbide (a-SiC) layer was deposited on the carbide substrate by magnetron sputtering catalyzed by Co, a binding phase of carbide substrate, to form SGF under thermal annealing at 1000 °C. The influence of the interfacial layer on the graphene structure was investigated as a function of annealing time. As a result, the phase of the interfacial layer is a critical factor affecting the formation and structure of SGF. As the annealing time increases, the interfacial phase is transformed from CoSi to Co₂Si, and then a pure Co₂Si particles layer is formed. The C atoms, attached to the Co₂Si particles, gather thereon and form the SGF. When the interfacial phase is a mixture of CoSi and Co₂Si, multilayer graphene comprising many defects is formed. A bilayer graphene is obtained when the interfacial layer is composed of pure Co₂Si.