Anomalous Lattice Vibrations of Single- and Few-Layer MoS 2

作者：Changgu Lee, Hugen Yan, Louis E. Brus, Tony F. Heinz, James Hone, Sunmin Ryu · 发表于：ACS Nano · 年份：2010 · DOI：10.1021/nn1003937 · 被引用次数：4858 · 研究领域：2D Materials and Applications、Organic and Molecular Conductors Research、Graphene research and applications

Molybdenum disulfide (MoS(2)) of single- and few-layer thickness was exfoliated on SiO(2)/Si substrate and characterized by Raman spectroscopy. The number of S-Mo-S layers of the samples was independently determined by contact-mode atomic force microscopy. Two Raman modes, E(1)(2g) and A(1g), exhibited sensitive thickness dependence, with the frequency of the former decreasing and that of the latter increasing with thickness. The results provide a convenient and reliable means for determining layer thickness with atomic-level precision. The opposite direction of the frequency shifts, which cannot be explained solely by van der Waals interlayer coupling, is attributed to Coulombic interactions and possible stacking-induced changes of the intralayer bonding. This work exemplifies the evolution of structural parameters in layered materials in changing from the three-dimensional to the two-dimensional regime.