Neumann C, Reichardt S, Venezuela P, Drögeler M, Banszerus L, Schmitz M, Watanabe K, Taniguchi T, Mauri F, Beschoten B, Rotkin S V, Stampfer C
JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, Aachen 52074, Germany.
Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Jülich 52425, Germany.
Nat Commun. 2015 Sep 29;6:8429. doi: 10.1038/ncomms9429.
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.
共焦拉曼光谱已成为用于石墨烯非侵入性表征的一种主要的、多功能的工具。尽管它已成功用于确定层数、边缘质量以及应变、掺杂和无序的影响，但实验观察到的最显著拉曼2D线展宽的本质仍不清楚。在这里，我们表明，观察到的2D线宽包含了关于石墨烯中应变变化的有价值信息，这些应变变化发生在远低于激光光斑尺寸的长度尺度上，即纳米尺度上。这一发现具有高度相关性，因为最近已经表明，这种纳米尺度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线宽是用于分类石墨烯的晶体质量、纳米尺度平整度以及局部电子性质的一个良好且易于获取的量，所有这些对于未来的科学和工业应用都很重要。
