Rapid growth of large-area single-crystal graphene film by seamless stitching using resolidified copper foil on a molybdenum substrate

Graphene grain boundaries are inevitably formed during the stitching of graphene domains, consequently degrading the graphene film quality. Herein, we have developed a new strategy to grow large-area single-crystal graphene film using resolidified Cu foil on a Mo substrate. The Cu foil resolidifies into a quasi-atomically smooth Cu film, and recrystallizes into a single-crystal Cu (111) film sticking to the Mo foil surface after annealing above the Cu melting point under a H₂ atmosphere. A single-crystal graphene film of more than 2 inches in size is obtained by seamless stitching of more than 99% ultra-highly oriented single-crystal graphene domains of ∼500 μm on the resolidified Cu (111) surface, and it shows a low average sheet resistance of 315 Ω sq^-1 and a high optical transmittance of ∼97.6%. Moreover, the field-effect mobility of the single-crystal graphene film reaches up to 11500 cm² V^-1 s^-1, significantly higher than that of polycrystalline graphene film (∼4260 cm² V^-1 s^-1). This approach can easily be scaled up to achieve large-area and high-quality graphene film with a single crystal nature, and thereby realize various industrial-level applications at low cost.