Observation of interlayer phonon modes in van der Waals heterostructures

Abstract

We have investigated the vibrational properties of van der Waals heterostructures of monolayer transition metal dichalcogenides (TMDs), specifically MoS2/WSe2 and MoSe2/MoS2 heterobilayers as well as twisted MoS2 bilayers, by means of ultralow-frequency Raman spectroscopy. We discovered Raman features (at 30 ~ 40 cm-1) that arise from the layer-breathing mode (LBM) vibrations between the two incommensurate TMD monolayers in these structures. The LBM Raman intensity correlates strongly with the suppression of photoluminescence that arises from interlayer charge transfer. The LBM is generated only in bilayer areas with direct layer-layer contact and atomically clean interface. Its frequency also evolves systematically with the relative orientation between of the two layers. Our research demonstrates that LBM can serve as a sensitive probe to the interface environment and interlayer interactions in van der Waals materials.

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Cited by in corpus (11)

• 2D materials and van der Waals heterostructures
• Photocurrent generation with two-dimensional van der Waals semiconductors
• Interlayer coupling in commensurate and incommensurate bilayer structures of transition metal dichalcogenides
• Activation of new Raman modes by inversion symmetry breaking in type II Weyl semimetal candidate T'-MoTe2
• Seebeck Coefficient of a Single van der Waals Junction in Twisted Bilayer Graphene
• Stacking-Dependent Interlayer Phonons in 3R and 2H MoS${}_2$
• Interlayer bond polarizability model for stacking-dependent low-frequency Raman scattering in layered materials
• Low-frequency Raman scattering in WSe${}_2$-MoSe${}_2$ heterobilayers: Evidence for atomic reconstruction
• Rigid-layer Raman-active modes in $N$-layer Transition Metal Dichalcogenides: interlayer force constants and hyperspectral Raman imaging
• Interlayer exciton-polaron in atomically thin semiconductors
• Suppression of the Shear Raman Mode in Defective Bilayer MoS2