Issue 29, 2019

Anomalous lattice vibrations of CVD-grown monolayer MoS2 probed using linear polarized excitation light

Abstract

A novel physical phenomenon and advanced application have been explored in 2D low-dimensional van der Waals layered materials due to their reduced in-plane symmetry. The light–matter interaction is observed upon rapid characterization of the 2D material's crystal orientation. Here, the effects of the sample's rotation angle and the incident light's linear polarization angle on the Raman scattering of chemical vapor deposition (CVD)-grown monolayer MoS2 were investigated. The results show that the crystal orientation of monolayer MoS2 can be distinguished by analyzing the intensity ratio and frequency difference of its two dominant Raman vibration modes. In addition, an increase in the incident light's power intensity causes the Raman peaks to red shift due to the photothermal effect. Strikingly, it was found that, with an increase in the incident linear polarization angle, the out-of-plane A1g phonon mode red shifts, while the in-plane E2g1 phonon mode blue shifts. The frequency difference consequently decreases from 19.5 cm−1 to 17.4 cm−1. The anomalous lattice vibrations of monolayer MoS2 originate from the built-in strain introduced by the SiO2/Si substrate. This work paves the way for the investigation and characterization of 2D MoS2, providing further understanding of the light–matter interaction in 2D materials, which is beneficial for advanced studies on anisotropic MoS2 based electronic and photoelectric information technologies and sensing applications.

Graphical abstract: Anomalous lattice vibrations of CVD-grown monolayer MoS2 probed using linear polarized excitation light

Supplementary files

Article information

Article type
Communication
Submitted
14 Apr. 2019
Accepted
20 Jūn. 2019
First published
20 Jūn. 2019

Nanoscale, 2019,11, 13725-13730

Anomalous lattice vibrations of CVD-grown monolayer MoS2 probed using linear polarized excitation light

F. Li, T. Huang, Y. Lan, T. Lu, T. Shen, K. B. Simbulan and J. Qi, Nanoscale, 2019, 11, 13725 DOI: 10.1039/C9NR03203G

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