Preparation of meter-scale Cu foils with decimeter grains and the use for the synthesis of graphene films

Chemical vapor deposition (CVD) is the most promising method for the preparation of high-quality and large-area graphene films, especially the epitaxial growth of graphene on large-area single-crystal Cu foils. While single-crystal Cu foils are normally achieved by thermally annealing the commercial polycrystalline Cu foils, their size and therefore the size of graphene films grown on them are limited to the size of the reaction chamber. We report a simple and feasible method to prepare large-area Cu foils with decimeter grains by thermally annealing the rolled-up Cu foils, where the Cu layers are separated by thin porous carbon fiber cloths. The carbon fiber cloths prevent Cu layers from sticking to each other at high temperatures while do not block the gas transportation. In such a way, the utilization efficiency of the reaction chamber is significantly improved, e.g., 0.2 m × (1–2) m Cu foils can be processed even in a 5 cm diameter quartz tube chamber. High-quality graphene films grown on such Cu foils are then demonstrated. This method may be suitable for the annealing of other metal foils to enlarge grain size and the synthesis of other two-dimensional materials on them such as h-BN.