Excitation energy dependence of Raman spectra of few-layer WS2

Yang, Jinho; Lee, Jae-Ung; Cheong, Hyeonsik

doi:10.1016/j.flatc.2017.06.001

Cited by 55 publications

(67 citation statements)

References 62 publications

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“…2b. The interlayer LB coupling of WS 2 ( α ⊥ (W) = 9.0 × 10 19 Nm −3 ) is known from the previous experiments 41 , while that ( α ⊥ (BN)) in hBN and the interfacial LB coupling ( α ⊥ (I)) between hBN and WS 2 constituents can be fitting parameters of the LCM. The experimental Pos(LB) of all n L-hBN/ m LW () in Fig.…”

Section: Resultsmentioning

confidence: 96%

Cross-dimensional electron-phonon coupling in van der Waals heterostructures

Lin

Zhou

et al. 2019

Nat Commun

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The electron-phonon coupling (EPC) in a material is at the frontier of the fundamental research, underlying many quantum behaviors. van der Waals heterostructures (vdWHs) provide an ideal platform to reveal the intrinsic interaction between their electrons and phonons. In particular, the flexible van der Waals stacking of different atomic crystals leads to multiple opportunities to engineer the interlayer phonon modes for EPC. Here, in hBN/WS 2 vdWH, we report the strong cross-dimensional coupling between the layer-breathing phonons well extended over tens to hundreds of layer thick vdWH and the electrons localized within the few-layer WS 2 constituent. The strength of such cross-dimensional EPC can be well reproduced by a microscopic picture through the mediation by the interfacial coupling and also the interlayer bond polarizability model in vdWHs. The study on cross-dimensional EPC paves the way to manipulate the interaction between electrons and phonons in various vdWHs by interfacial engineering for possible interesting physical phenomena.

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Section: Resultsmentioning

confidence: 96%

Cross-dimensional electron-phonon coupling in van der Waals heterostructures

Lin

Zhou

et al. 2019

Nat Commun

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“…In the upconversion photoluminescence process, the A 2 ’’ vibration at 441 cm −1 (~55 meV) 36 can be also considered. This phonon is Raman inactive in bulk, but becomes partially active for one or a few layers under resonant excitation 37 .…”

Section: Resultsmentioning

confidence: 99%

Room temperature multi-phonon upconversion photoluminescence in monolayer semiconductor WS2

et al. 2019

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Photon upconversion is an anti-Stokes process in which an absorption of a photon leads to a reemission of a photon at an energy higher than the excitation energy. The upconversion photoemission has been already demonstrated in rare earth atoms in glasses, semiconductor quantum wells, nanobelts, carbon nanotubes and atomically thin semiconductors. Here, we demonstrate a room temperature upconversion photoluminescence process in a monolayer semiconductor WS2, with energy gain up to 150 meV. We attribute this process to transitions involving trions and many phonons and free exciton complexes. These results are very promising for energy harvesting, laser refrigeration and optoelectronics at the nanoscale.

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“…Very recently, Yang et al . 39 and Tan et al . 40 investigated the excitation energy dependence of low-frequency Raman scattering spectra in few-layer WS 2 .…”

Section: Introductionmentioning

confidence: 95%

Deep-ultraviolet Raman scattering spectroscopy of monolayer WS2

Liu

Yang

Tatsumi

et al. 2018

Sci Rep

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Raman scattering measurements of monolayer WS2 are reported as a function of the laser excitation energies from the near-infrared (1.58 eV) to the deep-ultraviolet (4.82 eV). In particular, we observed several strong Raman peaks in the range of 700∼850 cm−1 with the deep-ultraviolet laser lights (4.66 eV and 4.82 eV). Using the first-principles calculations, these peaks and other weak peaks were appropriately assigned by the double resonance Raman scattering spectra of phonons around the M and K points in the hexagonal Brillouin zone. The relative intensity of the first-order to A1g peak changes dramatically with the 1.58 eV and 2.33 eV laser excitations, while the comparable relative intensity was observed for other laser energies. The disappearance of the peak with the 1.58 eV laser light comes from the fact that valley polarization of the laser light surpasses the mode since the mode is the helicity-exchange Raman mode. On the other hand, the disappearance of the A1g peak with the 2.33 eV laser light might be due to the strain effect on the electron-phonon matrix element.

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Excitation energy dependence of Raman spectra of few-layer WS2

Cited by 55 publications

References 62 publications

Cross-dimensional electron-phonon coupling in van der Waals heterostructures

Cross-dimensional electron-phonon coupling in van der Waals heterostructures

Room temperature multi-phonon upconversion photoluminescence in monolayer semiconductor WS2

Deep-ultraviolet Raman scattering spectroscopy of monolayer WS2

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