Advanced Functional Materials· 2012Q1
From Bulk to Monolayer MoS<sub>2</sub>: Evolution of Raman Scattering
- 4,200citations
- Q1SCImago
- 2012year
Short summary
Raman spectroscopy reveals that only the $ E_{2{ m g}}^1 $ and $ A_{{ m 1g}}^{} $ peak frequencies of MoS<sub>2</sub> vary predictably with layer number, while intensities and widths fluctuate arbitrarily.
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Key points
- Only $ E_{2{ m g}}^1 $ and $ A_{{ m 1g}}^{} $ Raman peak frequencies of MoS<sub>2</sub> change predictably with layer number.
- Peak intensities and widths of MoS<sub>2</sub> vary arbitrarily with layer number.
- Electron-phonon coupling weakens in ultrathin MoS<sub>2</sub> due to increased electronic transition energies or elongated bonds.
- The 454 cm<sup>−1</sup> Raman peak is a combinational band of LA(M) and $ A_{{ m 2u}}^{} $ modes, not an overtone.
AI-generated from the title and abstract; the full text is not read.
Abstract
Abstract Molybdenum disulfide (MoS 2 ) is systematically studied using Raman spectroscopy with ultraviolet and visible laser lines. It is shown that only the Raman frequencies of $ E_{2{\rm g}}^1 $ and $ A_{{\rm 1g}}^{} $ peaks vary monotonously with the layer number of ultrathin MoS 2 flakes, while intensities or widths of the peaks vary arbitrarily. The coupling between electronic transitions and phonons are found to become weaker when the layer number of MoS 2 decreases, attributed to the increased electronic transition energies or elongated intralayer atomic bonds in ultrathin MoS 2 . The asymmetric Raman peak at 454 cm −1 , which has been regarded as the overtone of longitudinal optical M phonons in bulk MoS 2 , is actually a combinational band involving a longitudinal acoustic mode (LA(M)) and an optical mode ( $ A_{{\rm 2u}}^{} $ ). Our findings suggest a clear evolution of the coupling between electronic transition and phonon when MoS 2 is scaled down from three‐ to two‐dimensional geometry.
The authors' abstract, as published at the source. Advanced Functional Materials, 2012 · DOI ↗
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Field: Materials Chemistry
Materials ChemistryMaterials Science