Tailoring phonon modes of few-layered MoS2 by in-plane electric field

Sreemanta Mitra*, Divya Srivastava, Shib Shankar Singha, Saurav Dutta, Biswarup Satpati, Maarit Karppinen, Arindam Ghosh, Achintya Singha

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

We discuss the effect of the in-plane electric field on the Raman spectroscopy for few-layered MoS2. The characteristic Raman modes of MoS2 show gradual red shift, while the intensity increases by 45–50% as the electric field is increased, showing a large electro-optical effect. Structural analysis suggests that our few-layered MoS2 belongs to P6/m2 space group with broken inversion symmetry. We attribute this gradual red shift to this broken symmetry-driven piezoelectricity in MoS2, which generates tensile strain along the perpendicular direction when the electric field is applied. The enhancement of the effect upon reversing the electric field direction adds credence to our interpretation. Our first principal density-functional theory calculation further substantiates the claim. This optical probing of the electromechanical coupling may lead to applications as a nonextensive technique for electric field/strain sensors in the nanoelectronics devices.

Original languageEnglish
Article number6
Journalnpj 2D Materials and Applications
Volume4
Issue number1
DOIs
Publication statusPublished - 30 Apr 2020
MoE publication typeA1 Journal article-refereed

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