Adsorptions and diffusions of carbon atoms on the surface and in the subsurface of Co （200）： A first-principles density-functional study

• Published in: 中国物理B：英文版 2014 (8), p.75-80
• Main Author: Qiao Liang Wang Shu-Min Zhang Xiao-Ming Hu Xiao-Ying ZengYi Zheng Wei-Tao
• Format: Article
• Language: English
• Subjects: 化学气相沉积; 吸附结构; 密度泛函理论; 扩散; 碳原子; 第一原理计算; 表面偏析; 钴
• ISSN: 1674-1056; 2058-3834

First-principles calculations based on density functional theory are used to investigate the adsorptions and diffusions of carbon atoms on the surface and in the subsurface of Co （200）. The preferred site for the carbon atom on the surface is the hollow site, and the preferred site in the subsurface is the octahedral site. There is charge transfer from the surface to the adsorbed carbon atom, and for the most favorable adsorbed structure the charge transfer is largest. Moreover, the energy barriers for the diffusions of carbon atoms on the surface and from the surface into the subsurface and then back to the surface are calculated in detail. The results indicate that the energy barrier for the diffusion of carbon atoms on the surface is comparable to that from the subsurface to the surface. The results imply that both the direct surface nucleation and the surface segregation from Co bulk can be observed in the chemical vapor deposition growth of graphene on Co （200） substrate, which can gain a new insight into the growth mechanism of graphene.