Kramers-Kronig analysis of the reflectivity spectra of 3R-WS<sub>2</sub>and 2H-WSe<sub>2</sub>

Beal, A R; Liang, W. Y.; Hughes, H. P.

doi:10.1088/0022-3719/9/12/027

Cited by 125 publications

(176 citation statements)

References 9 publications

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“…For WSe 2 , the impact of strongly deviating optical properties ðn; kÞ for atomically thin films was also considered. In particular, we compared the color rendering of ðn; kÞ data from a 2.8 nm thin WSe 2 flake 33 with those of bulk material 34 and found no substantial difference. However, the source of the ðn; kÞ values can generally have a strong effect for other materials, e.g., h-BN.…”

Section: Calculation Modelmentioning

confidence: 97%

Visibility of two-dimensional layered materials on various substrates

Müller

Gumprich

Eçik

et al. 2015

Journal of Applied Physics

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For the investigation of 2D layered materials such as graphene, transition-metal dichalcogenides, boron nitride, and their heterostructures, dedicated substrates are required to enable unambiguous identification through optical microscopy. A systematic study is conducted, focusing on various 2D layered materials and substrates. The simulated colors are displayed and compared with microscopy images. Additionally, the issue of defining an appropriate index for measuring the degree of visibility is discussed. For a wide range of substrate stacks, layer thicknesses for optimum visibility are given along with the resulting sRGB colors. Further simulations of customized stacks can be conducted using our simulation tool, which is available for download and contains a database featuring a wide range of materials. V C 2015 AIP Publishing LLC.

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Section: Calculation Modelmentioning

confidence: 97%

Visibility of two-dimensional layered materials on various substrates

Müller

Gumprich

Eçik

et al. 2015

Journal of Applied Physics

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“…We assume that the dielectric function of the monolayer at the higher energy ranges is similar to that of bulk counterparts, and use the dielectric function of the bulk counterparts, which is available in reference (Ref. 27 in the main text), to correct the oscillators of the monolayers in the higher energy range. Multiple oscillators are set with equal space of 0.1eV and almost equal damping constant 0.3eV.…”

Section: S1 Fitting Dielectric Function Using a Multi-lorentzian Modelmentioning

confidence: 99%

“…the higher energy ranges is similar to that of bulk counterparts, and use the dielectric function of the bulk counterparts, which is available in reference 27 , to correct the oscillators of the monolayers in the higher energy range. This strategy has been previously demonstrated able to give rise to reasonably accurate dielectric function of TMD monolayers from spectral reflectance 23 .…”

mentioning

confidence: 99%

Giant Gating Tunability of Optical Refractive Index in Transition Metal Dichalcogenide Monolayers

Yu¹,

Yu²,

Huang³

et al. 2017

Nano Lett.

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We report that the refractive index of transition metal dichacolgenide (TMDC) monolayers, such as MoS2, WS2, and WSe2, can be substantially tuned by > 60% in the imaginary part and > 20% in the real part around exciton resonances using CMOS-compatible electrical gating. This giant tunablility is rooted in the dominance of excitonic effects in the refractive index of the monolayers and the strong susceptibility of the excitons to the influence of injected charge carriers. The tunability mainly results from the effects of injected charge carriers to broaden the spectral width of excitonic interband transitions and to facilitate the interconversion of neutral and charged excitons. The other effects of the injected charge carriers, such as renormalizing bandgap and changing exciton binding energy, only play negligible roles. We also demonstrate that the atomically thin monolayers, when combined with photonic structures, can enable the efficiencies of optical absorption (reflection) tuned from 40% (60%) to 80% (20%) due to the giant tunability of refractive index. This work may pave the way towards the development of field-effect photonics in which the optical functionality can be controlled with CMOS circuits.

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“…[10][11][12] Beal, Knights and Liang measured the transmission spectra of 2H-WSe 2 at liquid-helium temperature in the energy range of 1.5-4.5 eV. 10 The normal-incidence reflectivity spectra using polarized light PHYSICAL REVIEW B 15 SEPTEMBER 1999-II VOLUME 60, NUMBER 12 PRB 60 0163-1829/99/60͑12͒/8610͑6͒/$15.00 8610 ©1999 The American Physical Society was measured for Eʈc and EЌc at 78 K and 300 K in the energy range 1.5-4.5 eV.…”

Section: Introductionmentioning

confidence: 99%

Optical properties and band structure of2H−WSe2

et al. 1999

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We have calculated the electronic band structure of 2H-WSe 2 , within the local-density approximation using the linear muffin-tin orbital method in the atomic sphere approximation as well as the full potential linear augmented plane-wave ͑FPLAPW͒ method. Using the self-consistent potentials, we have calculated the frequency dependent anisotropic dielectric functions ⑀ ʈ () and ⑀ Ќ () corresponding to the electric field parallel and perpendicular to the c axis. The results of these calculations are compared with experimental data and show better agreement for the FPLAPW calculation. We have included the spin-orbit coupling in the calculation of the frequency dependent dielectric function using the FPLAPW and find the effect to be small.

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Kramers-Kronig analysis of the reflectivity spectra of 3R-WS₂and 2H-WSe₂

Cited by 125 publications

References 9 publications

Visibility of two-dimensional layered materials on various substrates

Visibility of two-dimensional layered materials on various substrates

Giant Gating Tunability of Optical Refractive Index in Transition Metal Dichalcogenide Monolayers

Optical properties and band structure of2H−WSe2

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Kramers-Kronig analysis of the reflectivity spectra of 3R-WS2and 2H-WSe2

Cited by 125 publications

References 9 publications

Visibility of two-dimensional layered materials on various substrates

Visibility of two-dimensional layered materials on various substrates

Giant Gating Tunability of Optical Refractive Index in Transition Metal Dichalcogenide Monolayers

Optical properties and band structure of2H−WSe2

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Kramers-Kronig analysis of the reflectivity spectra of 3R-WS₂and 2H-WSe₂