Temperature induced modulation of resonant Raman scattering in bilayer 2H-MoS${}_2$

Abstract

The temperature evolution of the resonant Raman scattering from high-quality bilayer 2H-MoS${}_2$ encapsulated in hexagonal BN flakes is presented. The observed resonant Raman scattering spectrum as initiated by the laser energy of 1.96 eV, close to the A excitonic resonance, shows rich and distinct vibrational features that are otherwise not observed in non-resonant scattering. The appearance of 1${}^{st}$ and 2${}^{nd}$ order phonon modes is unambiguously observed in a broad range of temperatures from 5 K to 320 K. The spectrum includes the Raman-active modes, $i.e.$ E${}_{\text{1g}}^2$($\Gamma$) and A${}_{\text{1g}}$($\Gamma$) along with their Davydov-split counterparts, $i.e.$ E${}_{\text{1u}}$($\Gamma$) and B${}_{\text{1u}}$($\Gamma$). The temperature evolution of the Raman scattering spectrum brings forward key observations, as the integrated intensity profiles of different phonon modes show diverse trends. The Raman-active A${}_{1g}$($\Gamma$) mode, which dominates the Raman scattering spectrum at $T$=5~K quenches with increasing temperature. Surprisingly, at room temperature the B${}_{\text{1u}}$($\Gamma$) mode, which is infrared-active in the bilayer, is substantially stronger than its nominally Raman-active A${}_{\text{1g}}$($\Gamma$) counterpart.

7 pages, 3 figures

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• Twistronics: Manipulating the Electronic Properties of Two-dimensional Layered Structures through their Twist Angle
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Cited by in corpus (5)

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• Resonant Raman Scattering of Few Layers CrBr${}_3$
• Raman scattering excitation in monolayers of semiconducting transition metal dichalcogenides
• The effect of temperature and excitation energy on Raman scattering in bulk HfS${}_2$
• Phonon-assisted photoluminescence of bilayer MoS${}_2$ from first principles