Bilayer graphene (BLG) shows great application prospect and potential in next-generation electronics because of its unique electrical and mechanical properties. However, the scalable synthesis of large-area high-quality BLG films is still a great challenge, despite the maturity of chemical vapor deposition (CVD) technique. In this study, we report a robust method to grow BLGs on flat, softened Cu foils by atmospheric pressure CVD. A moderate amount of residual oxygen accelerates the growth of BLG domains while suppressing the formation of multilayers. Raising the nucleation density at low hydrogen pressure efficiently increases the film continuity. Based on the optimized CVD process, the growth of graphene films on 4×4 cm 2 Cu foils with an average BLG coverage of 76% is achieved. The morphology and structure characterizations demonstrate a high quality of the BLG. Dual gate field-effect transistors are investigated based on AB-stacked BLG, with a tunable bandgap and high carrier mobility of up to 6790 cm 2 V −1 s −1 at room temperature.

Precursors and catalysts play vital roles in chemical reactions. Considerable efforts have been devoted to the investigation of catalysts for graphene growth by chemical vapor deposition in recent years. However, there has been little research on precursors because of a lack of innovation in term of creating a controllable feeding method. Herein, we present a novel sustained and controlled release approach, and develop a convenient, safe, and potentially scalable feeding system with the assistance of matrix materials and a simple portable feeder. As a result, a highly volatile liquid precursor can be fed accurately to grow large‐area, uniform graphene films with optimal properties. This feeding approach will further benefit the synthesis of other two‐dimensional materials from various precursors.