Abstract Graphene is expected to be one of the most promising materials for nanoelectronics and spintronics. In most graphene-based devices, the graphene channel is placed on insulating substrates. Therefore, the study of interfacial interactions between graphene and the insulator surface is of critical importance. In this study, the vertical arrangement of graphene which is transferred on α-Al2O3(0001) has been studied by normal incidence X-ray standing wave (NIXSW) technique. The analysis of the NIXSW profile reveals that the graphene layer is located at 3.57 A above the α-Al2O3(0001) surface, which is larger than the interlayer distance of graphite (3.356 A). Micro-Raman spectroscopy shows that the transferred graphene has a limited spatial distribution of hole concentration. The present study shows that transferred graphene on the sapphire substrate followed by vacuum-annealing has an atomically flat surface free from residual contaminations such as organic compounds and there occurs the hole-doping in graphene.

中文翻译：

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同步加速器 X 射线驻波表征转移石墨烯和 α-Al2O3(0001) 之间界面处的原子排列

摘要 石墨烯有望成为纳米电子学和自旋电子学最有前途的材料之一。在大多数基于石墨烯的器件中，石墨烯通道放置在绝缘基板上。因此，研究石墨烯与绝缘体表面之间的界面相互作用至关重要。在这项研究中，通过垂直入射 X 射线驻波 (NIXSW) 技术研究了在 α-Al2O3(0001) 上转移的石墨烯的垂直排列。NIXSW 剖面分析表明，石墨烯层位于 α-Al2O3(0001) 表面上方 3.57 A，大于石墨的层间距离 (3.356 A)。微拉曼光谱表明，转移的石墨烯具有有限的空穴浓度空间分布。