Refractive index database

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Optical constants of WS2 (Tungsten disulfide)
Ermolaev et al. 2020: monolayer film; n,k 0.365–1.70 µm

Wavelength: µm

Complex refractive index (n+ik)[ i ]

n   k   LogX   LogY   eV

Derived optical constants

Conditions & Spec sheet

n_is_absolute: true
wavelength_is_vacuum: true
film_thickness: 1L
substrate: SiO2/Si


Optical constants of monolayer WS2 were measured by spectroscopic ellipsometry in the spectral range 365‑1700 nm. WS2 samples were grown on sapphire by atmospheric pressure chemical vapor deposition and then transferred on silicon wafers covered by 295 nm SiO2. Tauc–Lorentz oscillators were used in ellipsometry model to describe the optical response of excitons.


G. A. Ermolaev, D. I. Yakubovsky, Yu. V. Stebunov, A. V. Arsenin, V. S. Volkov. Spectral ellipsometry of monolayer transition metal dichalcogenides: Analysis of excitonic peaks in dispersion, J. Vac. Sci. Technol. B 38, 014002 (2020) (Numerical data kindly provided by Georgy Ermolaev)


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Tungsten disulfide, WS2

Tungsten disulfide (WS2) is a layered transition metal dichalcogenide that possesses distinct properties based on its structural morphology. In its three-dimensional bulk form, WS2 has indirect bandgap semiconducting properties, which contrasts its behavior when isolated to a monolayer or few-layer forms. When exfoliated to these thin layers, WS2 undergoes a transition to a direct bandgap semiconductor, making it intriguing for potential applications in electronics, optoelectronics, and photonics. This material's unique hexagonal structure gives it excellent lubrication capabilities, often preferred in environments with high pressures and temperatures. Furthermore, research continues into its promise in nanoelectronic devices, spintronic applications, and as a component in heterostructures with other two-dimensional materials.

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