▎ 摘　　要

The transfer process before graphene device fabrication could worsen the performance of graphene device greatly, so a transfer-free growth method for preparing graphene films is demanded urgently. Herein, we propose a novel three-step method to achieve transfer-free graphene films on Al2O3 (0001) substrates. Cu (111) films and carbon source were co-deposited on alpha-Al2O3 (0001) substrates by metalorganic chemical vapor deposition (MOCVD) at one step, then graphene was synthesis by a rapid annealing process, transforming the carbon source in copper into graphene films. Finally, a transfer-free graphene film with an ultra-smooth surface (similar to 3.49 nm) is achieved by etching the copper film on Al2O3(0001). Crystallographic characterization demonstrated the as-deposited Cu films show a nature of epitaxial single crystal, with a smooth surface (similar to 6.89 nm). Few layer graphene films (3-4 layers) with least defect concentration were grown at annealing time of 20 min. (C) 2018 Elsevier Ltd. All rights reserved.