Insights into Graphene-Copper Conductors: Evaluating Conductivity Enhancement and Measurement Challenges

Incorporating graphene (Gr) into copper (Cu) to enhance its electrical properties has become a focal point of research for applications such as microelectronics, electromagnetic shielding, and electric motors. This paper aims to replicate the samples and results from recent studies that reported “ultraconductivity” in Gr–Cu specimens. Moreover, it identifies potential sources of error in conductivity measurements for thin metal films and fine wires, commonly used as test samples in Gr–Cu research. The findings indicate that adding Gr only marginally improves the conductivity of Gr–Cu specimens in the sub-300 K range. However, it reduces their temperature coefficient of resistance (TCR) by about 3% in the 300–400 K range compared with reference samples. This study also investigates conduction mechanisms and electrical conductivity through atomistic simulations at ambient and elevated temperatures, testing several functionals to determine the most accurate approach for modeling the Gr/Cu hybrid system. Density functional theory (DFT) calculations confirm that changes in the electronic structure─arising from strong electron transfer from Cu to Gr, do not significantly increase electrical conductivity, contrary to popular belief. Instead, the marginal experimental increases are primarily attributed to alterations in the Cu microstructure rather than substantial improvements due to graphene incorporation.