拉曼光谱
钨
方向(向量空间)
图层(电子)
材料科学
光谱学
光学
物理
纳米技术
几何学
数学
冶金
量子力学
作者
Minjung Kim,Song‐Hee Han,Jung Hwa Kim,Jae‐Ung Lee,Zonghoon Lee,Hyeonsik Cheong
出处
期刊:2D materials
[IOP Publishing]
日期:2016-08-12
卷期号:3 (3): 034004-034004
被引量:46
标识
DOI:10.1088/2053-1583/3/3/034004
摘要
Orthorhombic tungsten ditelluride (WTe2), with a distorted 1T structure, exhibits a large magnetoresistance that depends on the orientation, and its electrical characteristics changes rom semimetallic to insulating as the thickness decreases. Through polarized Raman spectroscopy in combination with transmission electron diffraction, we establish a reliable method to determine the thickness and crystallographic orientation of few-layer WTe2. The Raman spectrum shows a pronounced dependence on the polarization of the excitation laser. We found that the separation between two Raman peaks at ~90 cm-1 and at 80-86 cm-1, depending on thickness, is a reliable fingerprint for determination of the thickness. For determination of the crystallographic orientation, the polarization dependence of the A1 modes, measured with the 632.8-nm excitation, turns out to be the most reliable. We also discovered that the polarization behaviors of some of the Raman peaks depend on the excitation wavelength as well as thickness, indicating a close interplay between the band structure and anisotropic Raman scattering cross section.
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