Large-Area Synthesis of High-Quality and Uniform Graphene Films on Copper Foils

TLDR

Graphene is prized for its unique band structure and physical properties, yet production is limited to small sizes due to reliance on graphite exfoliation. Large‑area centimeter‑scale graphene films were grown on copper by methane‑based CVD, with copper’s low carbon solubility rendering the process self‑limiting. The resulting films are largely single‑layer, continuous across copper steps and grain boundaries, and when transferred to Si/SiO₂ enable dual‑gated transistors with room‑temperature electron mobilities up to 4050 cm² V⁻¹ s⁻¹.

Abstract

Graphene has been attracting great interest because of its distinctive band structure and physical properties. Today, graphene is limited to small sizes because it is produced mostly by exfoliating graphite. We grew large-area graphene films of the order of centimeters on copper substrates by chemical vapor deposition using methane. The films are predominantly single-layer graphene, with a small percentage (less than 5%) of the area having few layers, and are continuous across copper surface steps and grain boundaries. The low solubility of carbon in copper appears to help make this growth process self-limiting. We also developed graphene film transfer processes to arbitrary substrates, and dual-gated field-effect transistors fabricated on silicon/silicon dioxide substrates showed electron mobilities as high as 4050 square centimeters per volt per second at room temperature.