Visualization of Grain Structure and Boundaries of Polycrystalline Graphene and Two-Dimensional Materials by Epitaxial Growth of Transition Metal Dichalcogenides
Visualization of Grain Structure and Boundaries of Polycrystalline Graphene and Two-Dimensional Materials by Epitaxial Growth of Transition Metal Dichalcogenides
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DOI：
10.1021/acsnano.5b05879
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发表时间：
2016-03-01
期刊：
影响因子：
17.1
通讯作者：
Tsuji, Masaharu
中科院分区：
文献类型：
--
作者：
Ago, Hiroki;Fukamachi, Satoru;Tsuji, Masaharu
在二维（2D）材料中，晶界的存在对材料的物理、电学和化学性质有很大的影响。由于二维材料生长大单晶的困难，揭示晶界的存在和特性成为实际应用的重要问题。在这里，我们提出了一种方法来可视化的晶粒结构和边界的二维材料，通过外延生长过渡金属二硫属化物（TMDC）在他们身上。在石墨烯表面上外延生长的二硫化钼（MoS2）的三角形单晶使我们能够确定石墨烯晶粒的取向和尺寸。多晶石墨烯中的晶界也是可视化的，反映了它们比基面更高的化学反应性。该方法已成功应用于石墨烯场效应晶体管，揭示了石墨烯通道的实际晶粒结构。此外，我们证明，这种方法可以扩展到确定其他二维材料，如二硫化钨（WS2）的晶粒结构。我们基于货车德瓦尔斯外延的可视化方法可以提供一种简便且大规模的标记技术来研究各种二维材料的晶粒结构，也有助于了解其晶粒结构与物理性能之间的关系。
The presence of grain boundaries in two-dimensional (2D) materials is known to greatly affect their physical, electrical, and chemical properties. Given the difficulty in growing perfect large single-crystals of 2D materials, revealing the presence and characteristics of grain boundaries becomes an important issue for practical applications. Here, we present a method to-visualize the grain structure and boundaries of 2D materials by epitaxially growing transition metal dichalcogenides (TMDCs) over them. Triangular single-crystals of molybdenum disulfide (MoS2) epitaxially grown on the surface of graphene allowed us to determine the orientation and size of the graphene grains. Grain boundaries in the polycrystalline graphene were also-visualized reflecting their higher chemical reactivity than the basal plane. The method was successfully applied to graphene field-effect transistors, revealing the actual grain structures of the graphene channels. Moreover, we demonstrate that this method can be extended to determine the grain structure of other 2D materials, such as tungsten disulfide (WS2). Our visualization method based on van der Waals epitaxy can offer a facile and large-scale labeling technique to investigate the grain structures of various 2D materials, and it will also contribute to understand the relationship between their grain structure and physical properties.