Feasibility and Structural Transformation of Electrodeposited Copper Foils for Graphene Synthesis by Plasma-Enhanced Chemical Vapor Deposition: Implications for High-Frequency Applications

Large-area graphene is typically synthesized on rolled-annealed copper foils, which require transferring to other substrates for applications. This study examines large-area graphene growth on electrodeposited (ED) copper foils—used in lithium-ion batteries and printed circuit boards—via plasma-enhanced chemical vapor deposition (PECVD). It reveals that, for a set plasma power, a minimum growth time ensures full graphene coverage, leading to monolayer and then multilayer graphene, showing PECVD growth on ED copper is not self-limited. The process also beneficially modifies the ED copper substrate, like removing the surface zinc layer and changing copper grain size and orientation, thus improving graphene growth. Additionally, the study includes high-frequency scattering parameter (S-parameter) measurements in a coplanar waveguide (CPW) system. This involves graphene on a sapphire substrate with a silver electrode. The S-parameter data indicate that the CPW with graphene shows reduced insertion losses in high-frequency circuits compared to those without graphene. This underscores graphene's role in reducing insertion losses between metallic and dielectric layers in high-frequency settings, offering valuable insights for industrial and technological applications.