Unusual Exciton-Phonon Interactions at van der Waals Engineered Interfaces

Abstract

Raman scattering is a ubiquitous phenomenon in light-matter interactions which reveals a material's electronic, structural and thermal properties. Controlling this process would enable new ways of studying and manipulating fundamental material properties. Here, we report a novel Raman scattering process at the interface between different van der Waals (vdW) materials as well as between a monolayer semiconductor and 3D crystalline substrates. We find that interfacing a WSe2 monolayer with materials such as SiO2, sapphire, and hexagonal boron nitride (hBN) enables Raman transitions with phonons which are either traditionally inactive or weak. This Raman scattering can be amplified by nearly two orders of magnitude when a foreign phonon mode is resonantly coupled to the A exciton in WSe2 directly, or via an A'1 optical phonon from WSe2. We further showed that the interfacial Raman scattering is distinct between hBN-encapsulated and hBN-sandwiched WSe2 sample geometries. This cross-platform electron-phonon coupling, as well as the sensitivity of 2D excitons to their phononic environments, will prove important in the understanding and engineering of optoelectronic devices based on vdW heterostructures.

Nano Letters: http://dx.doi.org/10.1021/acs.nanolett.6b04944

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Cited by in corpus (35)

• Excitons in atomically thin transition metal dichalcogenides
• Excitonic linewidth approaching the homogeneous limit in MoS2 based van der Waals heterostructures : accessing spin-valley dynamics
• Charged excitons in monolayer WSe${}_2$: experiment and theory
• Magneto-Optics of Exciton Rydberg States in a Monolayer Semiconductor
• The dielectric impact of layer distances on exciton and trion binding energies in van der Waals heterostructures
• Emerging Photoluminescence from the Dark-Exciton Phonon Replica in Monolayer WSe2
• Exciton-phonon coupling in MoSe2 monolayers
• Engineering of Neutral Excitons and Exciton Complexes in Transition Metal Dichalcogenide Monolayers through External Dielectric Screening
• Energy spectrum of two-dimensional excitons in a non-uniform dielectric medium
• Exciton states in monolayer MoSe2 and MoTe2 probed by upconversion spectroscopy
• Luminescent emission of excited Rydberg excitons from monolayer WSe2
• Atomic-scale mechanisms of defect- and light-induced oxidation and degradation of InSe
• Observation of the polaronic character of excitons in a two-dimensional semiconducting magnet $\mathrm{Cr}{\mathrm{I}}_3$
• Spatial extent of the excited exciton states in WS${}_2$ monolayers from diamagnetic shifts
• Superior valley polarization and coherence of 2s excitons in monolayer WSe2
• Dielectric Engineering of Electronic Correlations in a van der Waals Heterostructure
• Anisotropic structural dynamics of monolayer crystals revealed by femtosecond surface x-ray scattering
• Macroscopic Single-Phase Monolayer Borophene on Arbitrary Substrates
• Ultrafast coherent interlayer phonon dynamics in atomically thin layers of MnBi2Te4
• Excitonic Complexes and Emerging Interlayer Electron-Phonon Coupling in BN Encapsulated Monolayer Semiconductor Alloy: WS0.6Se1.4
• Probing Hyperbolic and Surface Phonon-Polaritons in 2D materials using Raman Spectroscopy
• New insights in the lattice dynamics of monolayers, bilayers, and trilayers of WSe2 and unambiguous determination of few-layer-flakes' thickness
• Dynamical screening effects of substrate phonons on two-dimensional excitons
• Direct Observation of Intravalley Phonon Scattering of 2s Excitons in MoSe${}_2$ and WSe${}_2$ Monolayers
• Spectrally tunable, large Raman enhancement from nonradiative energy transfer in van der Waals heterostructure
• Single-photon emitters in WSe${}_2$: Critical role of phonons on excitation schemes and indistinguishability
• Monolayer Semiconductor Auger Detector
• Optical signatures of exciton-polarons from diagrammatic Monte Carlo
• Valley Phenomena in the Candidate Phase Change Material WSe${}_{2(1-x)}$Te${}_{2x}$
• Impact of optically pumped non-equilibrium steady states on luminescence emission of atomically-thin semiconductor excitons
• Insights into hyperbolic phonon polaritons in hBN using Raman scattering from encapsulated transition metal dichalcogenide layers
• Resonant Raman scattering of surface phonon polaritons mediated by excitons in WSe${}_2$ films
• Magneto-Optical Measurements of the Negatively Charged 2$s$ Exciton in WSe${}_2$
• Origin of interlayer exciton-phonon coupling in 2D heterostructures
• Moiré exciton dynamics and moiré exciton-phonon interaction in a WSe${}_2$/MoSe${}_2$ heterobilayer