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arXiv 1107.1909cond-mat.mtrl-sci
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Cu(111)衬底上石墨烯镶嵌性的起源

Origin of the Mosaicity in Graphene Grown on Cu(111)

S. Nie, J. M. Wofford, N. C. Bartelt, O. D. Dubon, K. F. McCarty

摘要:

我们使用低能电子显微镜来研究石墨烯如何在Cu(111)上生长。石墨烯岛首先在衬底缺陷处成核,例如台阶束和杂质。这些岛的相当大的一部分可以与衬底旋转错位,产生晶粒边界后的冲击。新的旋转边界也产生了石墨烯生长跨越衬底步骤束。因此,较粗糙的基板比较平坦的基板导致更高程度的镶嵌性。增加生长温度改善晶体学对准。我们证明,石墨烯在Cu(111)上的生长是表面扩散限制通过比较模拟的时间演变的岛屿形状与实验。岛是具有不同叶的树枝状,但与在(100)织构铜箔上观察到的多晶四叶岛不同,每个岛都可以是单晶。因此,在光滑、干净的Cu(111)上的外延石墨烯具有比在Cu(100)上更少的结构缺陷。

英文摘要:

We use low-energy electron microscopy to investigate how graphene grows on Cu(111). Graphene islands first nucleate at substrate defects such as step bunches and impurities. A considerable fraction of these islands can be rotationally misaligned with the substrate, generating grain boundaries upon interisland impingement. New rotational boundaries are also generated as graphene grows across substrate step bunches. Thus, rougher substrates lead to higher degrees of mosaicity than do flatter substrates. Increasing the growth temperature improves crystallographic alignment. We demonstrate that graphene growth on Cu(111) is surface diffusion limited by comparing simulations of the time evolution of island shapes with experiments. Islands are dendritic with distinct lobes, but unlike the polycrystalline, four-lobed islands observed on (100)-textured Cu foils, each island can be a single crystal. Thus, epitaxial graphene on smooth, clean Cu(111) has fewer structural defects than it does on Cu(100).

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