Structural consequences of hydrogen intercalation of epitaxial graphene on SiC(0001)
Structural consequences of hydrogen intercalation of epitaxial graphene on SiC(0001)
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DOI：
10.1063/1.4899142
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发表时间：
2014-10-20
影响因子：
4
通讯作者：
Bedzyk, Michael J.
中科院分区：
文献类型：
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作者：
Emery, Jonathan D.;Wheeler, Virginia H.;Bedzyk, Michael J.
已知各种原子物种（例如氢）到外延石墨烯（EG）与其SiC衬底之间的界面的嵌入显著影响石墨烯覆盖层的电子性质。在这里，我们使用高分辨率的X射线反射率来研究用于形成准独立（QFS）EG/SiC（0001）的氢嵌入过程的结构后果。我们确认，界面层被转换成一个层结构上无法区分的覆盖石墨烯层。该新形成的石墨烯层变得与SiC衬底解耦，并且与膜内的其他石墨烯层一起沿着垂直移位大约2.1埃。在该过程中，总碳层的数量是保守的，并且我们没有观察到其他结构变化，例如层间插入或石墨烯d-间距的扩展。这些结果澄清了氢插层QFS-EG/SiC（0001）的不确定结构，并提供了一个精确的模型，为进一步了解该系统提供了基础和实际的理解。(C)2014 AIP Publishing LLC.
The intercalation of various atomic species, such as hydrogen, to the interface between epitaxial graphene (EG) and its SiC substrate is known to significantly influence the electronic properties of the graphene overlayers. Here, we use high-resolution X-ray reflectivity to investigate the structural consequences of the hydrogen intercalation process used in the formation of quasi-free-standing (QFS) EG/SiC(0001). We confirm that the interfacial layer is converted to a layer structurally indistinguishable from that of the overlying graphene layers. This newly formed graphene layer becomes decoupled from the SiC substrate and, along with the other graphene layers within the film, is vertically displaced by similar to 2.1 angstrom. The number of total carbon layers is conserved during the process, and we observe no other structural changes such as interlayer intercalation or expansion of the graphene d-spacing. These results clarify the under-determined structure of hydrogen intercalated QFS-EG/SiC(0001) and provide a precise model to inform further fundamental and practical understanding of the system. (C) 2014 AIP Publishing LLC.