Micro-Structure and Transport Mechanism in Graphene Copper Composites

The addition of nanocarbons to copper (Cu), specifically in the form of graphene (GN), has shown to enhance copper’s physical properties. GN-Cu nanocomposites can potentially achieve a higher current carrying capacity and a lower temperature-sensitivity of electrical resistivity compared with copper. These characteristics make GN-Cu materials interesting for several applications including but not limited to interconnects, high current power lines, and elevated-temperature rotating machines. Charge conduction in these materials is controlled by microstructural features as well as nanoscale interfacial phenomena between the GN and Cu. In this work, we analytically investigated the possibilities for an improved electrical conductivity in GN-Cu composites. Subsequently, GN-Cu samples were prepared by the consolidation of CVD Cu-graphene films under high pressures and temperatures. The effects of processing time, temperature, and pressure on both the structure and physical properties of the GN-Cu composite films were investigated. Finally, in-situ conductivity measurements of the Cu-GN interfaces were carried out. These measurements provide insights into transport mechanisms in nanocarbon-metal composites.