摘要
研究采用传统的二维材料制备方法——机械剥离法制备了厚度约为60 nm的MoS_(2)纳米薄片,由光学显微镜和原子力显微镜观察MoS_(2)薄片的形貌和厚度分布,并搭建了偏振拉曼测试系统,根据MoS_(2)薄片1.8 eV的能带分别选择633 nm(1.96 eV)和458 nm(2.71 eV)激光来激发MoS_(2)的共振和非共振拉曼散射,拉曼散射光经过光纤耦合进频谱仪获得拉曼光谱,由洛伦兹拟合确定了共振拉曼光谱中的特征模式,通过与非共振拉曼对比,分析出MoS_(2)的拉曼光谱在共振状态下会激发出新的拉曼模式。通过观察0°到360°之间不同偏振角度下的共振拉曼光谱和极坐标图,发现共振拉曼光谱中的所有模式均具有偏振相关性,且偏振相关的方式相似,均呈现双极纺锤形,结合拉曼张量理论模型计算出的拉曼强度理论值与实验数据几乎完全重合。
MoS_(2)nanosheets with the thickness of above 60 nm were prepared by mechanical stripping,a traditional two-dimensional material preparation method.The morphology and thickness distribution of MoS_(2)flakes were observed by optical microscope and atomic force microscope,and a polarization Raman test system was built.According to the 1.8 eV bandgap of MoS_(2)flakes,633 nm(1.96eV)and 458 nm(2.71 eV)lasers were selected to excite the resonance and non-resonance Raman scattering of MoS_(2)flakes.The Raman scattering light was coupled into a spectroscope through optical fiber to obtain the Raman spectra,and the characteristic modes in the resonance Raman spectrum were determined by Lorentz fitting.By comparing with non-resonant Raman spectrum,it was found that the Raman spectrum of MoS_(2)could arouse a new Raman mode in resonant state.In addition,the resonance Raman spectra and polar coordinates at different polarization angles from 0°to 360°were observed.It was found that all the modes in the resonance Raman spectra were polarization-dependent,and the ways of polarization-dependence were similar.The theoretical model of Raman tensor was also combined with the experiment,and the fitted intensity curve could almost coincide with the data points.
作者
张新悦
李睿
崔祥辰
ZHANG Xinyue;LI Rui;CUI Xiangchen(School of Optoelectronic Engineering and Instrumentation Science,Dalian University of Technology,Dalian Liaoning 116024,CHN)
出处
《光电子技术》
CAS
2022年第4期280-285,共6页
Optoelectronic Technology
基金
辽宁省重点研发计划项目(2020JH2/10500003)
中央高校基本科研业务费(DUT18RC(3)047 and DUT20RC(5)028)。
关键词
拉曼光谱
二维材料
共振拉曼
拉曼张量
Raman spectrum
two-dimension material
resonance Raman
Raman tensor
