Contrasting Behavior of Carbon Nucleation in the Initial Stages of Graphene Epitaxial Growth on Stepped Metal Surfaces
Contrasting Behavior of Carbon Nucleation in the Initial Stages of Graphene Epitaxial Growth on Stepped Metal Surfaces
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DOI：
10.1103/physrevlett.104.186101
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发表时间：
2010-05-07
影响因子：
8.6
通讯作者：
Zhang, Zhenyu
中科院分区：
文献类型：
--
作者：
Chen, Hua;Zhu, Wenguang;Zhang, Zhenyu
利用密度泛函理论中的第一性原理计算，我们研究了在三个代表性的阶梯金属表面：Ir（111）、Ru（0001）和Cu（111）上外延石墨烯生长的早期阶段C成核的能量学和动力学。我们发现，在Ir（111）和Ru（0001）的平面上，两个C原子相互排斥，而它们更倾向于在Cu（111）上形成二聚体。此外，Ir和Ru表面的台阶边缘不能作为单个碳原子的有效捕获中心，但可以很容易地促进碳二聚体的形成。这些不同的行为归因于C-C键和C-金属键之间的微妙竞争，并提出了一个简单的通用原理，以C-金属键强度作为最小输入来预测其他金属基底上C附着原子的成核位置。
Using first-principles calculations within density functional theory, we study the energetics and kinetics of C nucleation in the early stages of epitaxial graphene growth on three representative stepped metal surfaces: Ir(111), Ru(0001), and Cu(111). We find that on the flat surfaces of Ir(111) and Ru(0001), two C atoms repel each other, while they prefer to form a dimer on Cu(111). Moreover, the step edges on Ir and Ru surfaces cannot serve as effective trapping centers for single C adatoms, but can readily facilitate the formation of C dimers. These contrasting behaviors are attributed to the delicate competition between C-C bonding and C-metal bonding, and a simple generic principle is proposed to predict the nucleation sites of C adatoms on many other metal substrates with the C-metal bond strengths as the minimal inputs.