Synchronous Growth of High-Quality Bilayer Bernal Graphene: From Hexagonal Single-Crystal Domains to Wafer-Scale Homogeneous Films

摘要

The precise control of the domain structure, layer thickness, and stacking order of graphene has attracted intense interest because of its great potential for nanoelectronics applications. Much effort has been devoted to synthesize semiconducting Bernal (AB)-stacked bilayer graphene because of its tunable band structure and electronic properties that are unavailable to single-layer graphene. However, fast growth of large-scale bilayer graphene sheets with a high AB-stacking ratio and high mobility on copper poses a tremendous challenge, which has to overcome the self-limiting effect. This study reports a low-cost but facile method to rapidly synthesize bilayer Bernal graphene by atmospheric pressure chemical vapor deposition using polystyrene as the feedstock. The bilayer graphene grains and continuous film obtained are of high quality and exhibit field-effect hole mobilities as high as 5700 and 2200 cm(2) V-1 s(-1) at room temperature, respectively. In addition, a synchronous growth mechanism of bilayer graphene is revealed by monitoring the growth process, resulting in a high surface coverage of nearly 100% for a near-perfect AB-stacking order. This new synthesis route is significant for industrial application of bilayer graphene and investigation of the growth mechanism of graphene by the chemical vapor deposition process.