Raman spectroscopy as probe of nanometre-scale strain variations in graphene.
Raman spectroscopy as probe of nanometre-scale strain variations in graphene.
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DOI：
10.1038/ncomms9429
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发表时间：
2015-09-29
影响因子：
16.6
通讯作者：
Stampfer C
中科院分区：
文献类型：
--
作者：
Neumann C;Reichardt S;Venezuela P;Drögeler M;Banszerus L;Schmitz M;Watanabe K;Taniguchi T;Mauri F;Beschoten B;Rotkin SV;Stampfer C
共焦拉曼光谱已经成为石墨烯非侵入性表征的主要、通用的主力。虽然它被成功地用于确定层的数量，边缘的质量，以及应变，掺杂和无序的影响，实验观察到的最突出的拉曼2D线的加宽的性质仍然不清楚。在这里，我们表明，所观察到的2D线宽包含有价值的信息，在石墨烯的应变变化的长度尺度远低于激光光斑的大小，也就是说，在纳米尺度上。这一发现是高度相关的，因为最近已经表明，这种纳米级的应变变化限制了高质量石墨烯器件中的载流子迁移率。因此，2D线宽是用于对石墨烯的结晶质量、纳米级平坦度以及局部电子性质进行分类的良好且容易获得的量，所有这些对于未来的科学和工业应用都是重要的。拉曼光谱已成为石墨烯表征的宝贵工具，但拉曼2D谱线加宽的性质仍不清楚。在这里，Stampfer等人表明，拉曼2D线宽是绝缘衬底上石墨烯的纳米级应变变化的量度。
Confocal Raman spectroscopy has emerged as a major, versatile workhorse for the non-invasive characterization of graphene. Although it is successfully used to determine the number of layers, the quality of edges, and the effects of strain, doping and disorder, the nature of the experimentally observed broadening of the most prominent Raman 2D line has remained unclear. Here we show that the observed 2D line width contains valuable information on strain variations in graphene on length scales far below the laser spot size, that is, on the nanometre-scale. This finding is highly relevant as it has been shown recently that such nanometre-scaled strain variations limit the carrier mobility in high-quality graphene devices. Consequently, the 2D line width is a good and easily accessible quantity for classifying the crystalline quality, nanometre-scale flatness as well as local electronic properties of graphene, all important for future scientific and industrial applications. Raman spectroscopy has become an invaluable tool for graphene characterisation, yet the nature of the broadening of the Raman 2D line remains unclear. Here, Stampfer et al. show that the Raman 2D line width is a measure of nanometre-scale strain variations in graphene on insulating substrates.