双层石墨烯
石墨烯
拉曼光谱
材料科学
凝聚态物理
拉曼散射
光学
纳米技术
物理
作者
Robin W. Havener,Houlong L. Zhuang,Lola Brown,Richard G. Hennig,Jiwoong Park
出处
期刊:Nano Letters
[American Chemical Society]
日期:2012-05-25
卷期号:12 (6): 3162-3167
被引量:287
摘要
Few-layer graphene is a prototypical layered material, whose properties are determined by the relative orientations and interactions between layers. Exciting electrical and optical phenomena have been observed for the special case of Bernal-stacked few-layer graphene, but structure-property correlations in graphene which deviates from this structure are not well understood. Here, we combine two direct imaging techniques, dark-field transmission electron microscopy (DF-TEM) and widefield Raman imaging, to establish a robust, one-to-one correlation between twist angle and Raman intensity in twisted bilayer graphene (tBLG). The Raman G band intensity is strongly enhanced due to a previously unreported singularity in the joint density of states of tBLG, whose energy is exclusively a function of twist angle and whose optical transition strength is governed by interlayer interactions, enabling direct optical imaging of these parameters. Furthermore, our findings suggest future potential for novel optical and optoelectronic tBLG devices with angle-dependent, tunable characteristics.
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