Graphene/copper composite films: Interface regulation for enhanced electrical performance

Graphene/copper composites are promising highly conductive materials for synergistic high carrier density of copper and high carrier mobility of graphene. However, the weak interface interaction and poor electron transfer ability between the graphene and copper limited the increase in conductivity. Here, nitrogen-doped graphene sheets growing on copper films (NGs/Cu) were prepared by using silk fibroin as carbon source. The presence of N enhances interface bonding and modifies charge transport behavior, leading to increased conductivity. A maximum electrical conductivity of 6.58 × 107 S/m was obtained, which is 113% of that of International Annealed Copper Standard for conductivity. Hall measurements and first-principles calculations demonstrated that the increased conductivity is attributed to the altered charge transport behavior at the interface caused by defect N (pyridinic N, pyrrolic N). Nitrogen-doped graphene was shown to enhance the interaction between graphene and copper, providing a viable approach to improve the electrical properties of composite materials.