Asymmetric Growth of Monolayer Graphene on Cu Foil by Space‐Confined CVD

Abstract Chemical vapor deposition (CVD) is the most efficient method for growing graphene while its performance heavily relies on the growth environment. In this work, we examine the growth of continuous monolayer graphene films using CVD in an asymmetric environment by placing the Cu foil substrate on a specially designed semicircular quartz boat with grooves. We find that the asymmetry plays a key role in the growth of graphene and the quality of graphene on the bottom surface of Cu foil is higher than that on the top surface. This difference is attributed to different oxygen and carbon source concentration on the two surfaces of Cu foil, which leads to different nucleation density, grain size, and growth rate. COMSOL simulation confirms this hypothesis and reveals that the lower gas flow velocity on the bottom is responsible for the higher oxygen content and less carbon source supply, promoting higher‐quality graphene. Based on this asymmetric mechanism, we achieve stable and efficient batch production of high‐quality graphene using a special substrate support. Our method has guiding significance for the stable and batch growth of high‐quality graphene or other two dimensional (2D) materials in spatial design strategies.