Graphene defect engineering for optimizing the interface and mechanical properties of graphene/copper composites

Abstract

A graphene defect engineering strategy was proposed in this work to tailor the interface and mechanical properties of graphene/Cu composites. Plasma treatment was used to create surface defects (5–10 nm nanopores) on the basal-plane of starting graphene material but without considerably damaging the graphene structure. It was demonstrated that the CuxOy oxides were in situ formed at the defect sites of plasma-treated graphene in the sintering process, which played a bridging role in enhancing the interfacial adhesion of graphene with Cu matrix. Compared to the composites with untreated graphene, the composites with plasma-treated graphene exhibited a higher strength enhancement, and better interface stability in response to thermal cycling, which was ascribed to the CuxOy-coordinated improved interfacial bonding that provided efficient load transfer and thermal stress relaxation. Nevertheless, the overlong plasma treatment could severely damage the graphene structure and result in a reduced strength enhancement. This study suggests that the rational defect engineering of graphene is an efficient approach for optimizing the interface and mechanical properties of graphene/metal composites.