Bulk and surface optical absorption in molybdenum disulfide

Roxlo, C. B.; Chianelli, R. R.; Deckman, H. W.; Ruppert, A. F.; Wong, P. P.

doi:10.1116/1.574671

Cited by 95 publications

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“…2, we note that the lateral dimensions of the majority of MoS 2 flakes is ~100-200 nm, resulting in a large edge to surface area ratio. We suggest that in spite of operating at below the material bandgap, our device initiates modelocking because of saturable absorption from the edge-related sub-bandgap states [49,50]. The output wavelength is tunable from 1,535 to 1,565 nm (as shown in Fig.…”

Section: Wideband Tunable Ultrafast Er:fiber Laser Using Mos 2 -Pva Cmentioning

confidence: 98%

“…We propose that the large edge-to-surface ratio of the nanoflakes in the samples give rise to interband absorbing states [49]. Indeed, lithographically textured MoS 2 single crystals have been reported to exhibit over one order of magnitude higher sub-bandgap optical absorption than that observed in the single crystals due to energy levels arising from the edge states within the bandgap [50].…”

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confidence: 95%

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Solution processed MoS2-PVA composite for sub-bandgap mode-locking of a wideband tunable ultrafast Er:fiber laser

et al. 2015

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We fabricate a free-standing few-layer molybdenum disulfide (MoS 2 )-polymer composite by liquid phase exfoliation of chemically pristine MoS 2 crystals and use this to demonstrate a wideband tunable, ultrafast mode-locked fiber laser. Stable, picosecond pulses, tunable from 1,535 nm to 1,565 nm, are generated, corresponding to photon energies below the MoS 2 material bandgap. These results contribute to the growing body of work studying the nonlinear optical properties of transition metal dichalcogenides that present new opportunities for ultrafast photonic applications.

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Section: Wideband Tunable Ultrafast Er:fiber Laser Using Mos 2 -Pva Cmentioning

confidence: 98%

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confidence: 95%

Solution processed MoS2-PVA composite for sub-bandgap mode-locking of a wideband tunable ultrafast Er:fiber laser

et al. 2015

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“…The lamellar crystal of MoS 2 , as a semiconductor with a narrow band gap, can be efficiently excited by visible light to form the pair of electron and hole, and its layered structure is so similar to graphene or a botanical leaf that the light can be harvested on its surface maximally and the photogenerated electron can be transferred rapidly. Meanwhile, multilayer crystals of MoS 2 have semiconductor properties with an indirect band gap of ≈1.3 eV, whereas monolayer MoS 2 shows a direct optical band gap of ≈1.9 eV . Such a kind of MoS 2 with an adjustable band gap, therefore, has great significance in research and potential applications in photocatalysis, photoelectronic devices, solar cells, and so on .…”

Section: Introductionmentioning

confidence: 99%

Nano Ag‐Decorated MoS₂ Nanosheets from 1T to 2H Phase Conversion for Photocatalytically Reducing CO₂ to Methanol

et al. 2019

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Exfoliated MoS2 with a 2H phase has unique semiconductor properties and is used for the photocatalytic reduction of CO2 herein. Flower‐like MoS2 nanosheets are synthesized by the hydrothermal method and are used to fabricate an enlarged lamellar structure with a 1T phase of MoS2 in the presence of lithium ions under sonication; the 1T‐to‐2H phase conversion of MoS2 is successfully realized in o‐dichlorobenzene solution. To improve the photocatalytic performance, Ag nanoparticles are combined with the as‐prepared 2H‐MoS2 to form the Schottky knot. The obtained Ag/2H‐MoS2 composites are characterized and evaluated for their compositions, morphologies, microstructures, and photocatalytic activities in the reduction of CO2 to methanol. Herein, it was found that the electron and hole excited by light on the composites are more effectively separated through deposited nano Ag, and their photocatalytic ability of reducing CO2 to methanol is promoted simultaneously. The highest yield of methanol up to 365.08 μmol−1 g−1 h−1 appears at 20 wt% Ag on MoS2. Finally, a reasonable photocatalytic reaction mechanism is proposed.

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“…For example, the energy of the lowest optical transition in MoS 2 increases from 1.2 eV (ref. 12) in bulk to 1.9 eV (ref. 13) for a monolayer with an associated strong increase in photoluminescence 14 that has been attributed to the transition from indirect to direct band gap.…”

Section: Introductionmentioning

confidence: 99%

Probing the local nature of excitons and plasmons in few-layer MoS2

et al. 2017

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Excitons and plasmons are the two most fundamental types of collective electronic excitations occurring in solids. Traditionally, they have been studied separately using bulk techniques that probe their average energetic structure over large spatial regions. However, as the dimensions of materials and devices continue to shrink, it becomes crucial to understand how these excitations depend on local variations in the crystal-and chemical structure on the atomic scale. Here, we use monochromated low-loss scanning-transmission-electron-microscopy electron-energy-loss spectroscopy, providing the best simultaneous energy and spatial resolution achieved to-date to unravel the full set of electronic excitations in few-layer MoS 2 nanosheets over a wide energy range. Using first-principles, many-body calculations we confirm the excitonic nature of the peaks at~2 and~3 eV in the experimental electron-energy-loss spectrum and the plasmonic nature of higher energy-loss peaks. We also rationalise the non-trivial dependence of the electron-energy-loss spectrum on beam and sample geometry such as the number of atomic layers and distance to steps and edges. Moreover, we show that the excitonic features are dominated by the long wavelength (q = 0) components of the probing field, while the plasmonic features are sensitive to a much broader range of q-vectors, indicating a qualitative difference in the spatial character of the two types of collective excitations. Our work provides a template protocol for mapping the local nature of electronic excitations that open new possibilities for studying photo-absorption and energy transfer processes on a nanometer scale.

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Bulk and surface optical absorption in molybdenum disulfide

Abstract: Articles you may be interested inProtection and reduction of surface oxidation of Mo ∕ Si multilayers for extreme ultraviolet lithography projection optics by control of hydrocarbon gas atmosphere

Cited by 95 publications

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Solution processed MoS2-PVA composite for sub-bandgap mode-locking of a wideband tunable ultrafast Er:fiber laser

Solution processed MoS2-PVA composite for sub-bandgap mode-locking of a wideband tunable ultrafast Er:fiber laser

Nano Ag‐Decorated MoS₂ Nanosheets from 1T to 2H Phase Conversion for Photocatalytically Reducing CO₂ to Methanol

Probing the local nature of excitons and plasmons in few-layer MoS2

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Bulk and surface optical absorption in molybdenum disulfide

Abstract: Articles you may be interested inProtection and reduction of surface oxidation of Mo ∕ Si multilayers for extreme ultraviolet lithography projection optics by control of hydrocarbon gas atmosphere

Cited by 95 publications

References 0 publications

Solution processed MoS2-PVA composite for sub-bandgap mode-locking of a wideband tunable ultrafast Er:fiber laser

Solution processed MoS2-PVA composite for sub-bandgap mode-locking of a wideband tunable ultrafast Er:fiber laser

Nano Ag‐Decorated MoS2 Nanosheets from 1T to 2H Phase Conversion for Photocatalytically Reducing CO2 to Methanol

Probing the local nature of excitons and plasmons in few-layer MoS2

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Nano Ag‐Decorated MoS₂ Nanosheets from 1T to 2H Phase Conversion for Photocatalytically Reducing CO₂ to Methanol