Deparment of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, California 90095, United States.
J Am Chem Soc. 2011 Aug 17;133(32):12536-43. doi: 10.1021/ja200245p. Epub 2011 Jul 21.
Growth of graphene on copper (100) single crystals by chemical vapor deposition has been accomplished. The atomic structure of the graphene overlayer was studied using scanning tunneling microscopy. A detailed analysis of moiré superstructures present in the graphene topography reveals that growth occurs in a variety of orientations over the square atomic lattice of the copper surface. Transmission electron microscopy was used to elucidate the crystallinity of the grown graphene. Pristine, defect-free graphene was observed over copper steps, corners, and screw dislocations. Distinct protrusions, known as "flower" structures, were observed on flat terraces, which are attributed to carbon structures that depart from the characteristic honeycomb lattice. Continuous graphene growth also occurs over copper adatoms and atomic vacancies present at the single-crystal surface. The copper atom mobility within vacancy islands covered with suspended graphene sheets reveals a weak graphene-substrate interaction. The observed continuity and room-temperature vacancy motion indicates that copper mobility likely plays a significant role in the mechanism of sheet extension on copper substrates. Lastly, these results suggest that the quality of graphene grown on copper substrates is ultimately limited by nucleation at the surface of the metal catalyst.
通过化学气相沉积在铜（100）单晶上生长石墨烯已经实现。使用扫描隧道显微镜研究了石墨烯覆盖层的原子结构。对石墨烯形貌中存在的莫尔超结构的详细分析表明，在铜表面的正方形原子晶格上以各种取向生长。透射电子显微镜用于阐明生长石墨烯的结晶度。在铜台阶、角和螺旋位错上观察到了无缺陷的原始石墨烯。在平坦的台地上观察到了明显的突起，称为“花”结构，这归因于偏离特征蜂窝晶格的碳结构。在单晶表面上存在的铜原子吸附物和原子空位上也发生了连续的石墨烯生长。在悬空石墨烯片覆盖的空位岛中的铜原子迁移率表明石墨烯与基底的相互作用较弱。观察到的连续性和室温空位运动表明，铜的迁移率可能在铜基底上的片层扩展机制中起重要作用。最后，这些结果表明，在铜基底上生长的石墨烯的质量最终受到金属催化剂表面成核的限制。
