Optical response of monolayer, few-layer and bulk tungsten disulfide

Abstract

We present a comprehensive optical study of thin films of tungsten disulfide (WS${}_2$) with layer thicknesses ranging from mono- to octalayer and in the bulk limit. It is shown that the optical band-gap absorption of monolayer WS${}_2$ is governed by competing resonances arising from one neutral and two distinct negatively charged excitons whose contributions to the overall absorption of light vary as a function of temperature and carrier concentration. The photoluminescence response of monolayer WS${}_2$ is found to be largely dominated by disorder/impurity- and/or phonon-assisted recombination processes. The indirect band-gap luminescence in multilayer WS${}_2$ turns out to be a phonon-mediated process whose energy evolution with the number of layers surprisingly follows a simple model of a two-dimensional confinement. The energy position of the direct band-gap response (A and B resonances) is only weakly dependent on the layer thickness, which underlines an approximate compensation of the effect of the reduction of the exciton binding energy by the shrinkage of the apparent band gap. The A-exciton absorption-type spectra in multilayer WS${}_2$ display a non-trivial fine structure which results from the specific hybridization of the electronic states in the vicinity of the K-point of the Brillouin zone. The effects of temperature on the absorption-like and photoluminescence spectra of various WS${}_2$ layers are also quantified.

arXiv comment13 pages, 13 figures, electronic supporting information

References in corpus (53)

• Atomically thin MoS2: A new direct-gap semiconductor
• Two Dimensional Atomic Crystals
• Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides
• Control of valley polarization in monolayer MoS2 by optical helicity
• Observation of tightly bound trions in monolayer MoS2
• MoS_2 as an ideal material for valleytronics: valley-selective circular dichroism and valley Hall effect
• Exciton Binding Energy and Nonhydrogenic Rydberg Series in Monolayer WS2
• Evolution of Electronic Structure in Atomically Thin Sheets of WS2 and WSe2
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Light-emitting diodes by bandstructure engineering in van der Waals heterostructures
• Optical Spectrum of MoS${}_2$: Many-body Effects and Diversity of Exciton States
• Extraordinary room-temperature photoluminescence in WS2 monolayers
• Electrical Control of Two-Dimensional Neutral and Charged Excitons in a Monolayer Semiconductor
• Optical Generation of Excitonic Valley Coherence in Monolayer WSe2
• Phonons in single and few-layer MoS2 and WS2
• Measurement of the optical dielectric function of transition metal dichalcogenide monolayers: MoS2, MoSe2, WS2 and WSe2
• Tightly bound excitons in monolayer WSe2
• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Optical signature of symmetry variations and spin-valley coupling in atomically thin tungsten dichalcogenides
• Probing Excitonic Dark States in Single-layer Tungsten Disulfide
• Three-band tight-binding model for monolayers of group-VIB transition metal dichalcogenides
• Exciton Binding Energy of Monolayer WS2
• Large-scale quantum-emitter arrays in atomically thin semiconductors
• Electrical Control of Second-Harmonic Generation in a WSe2 Monolayer Transistor
• Deterministic strain-induced arrays of quantum emitters in a two-dimensional semiconductor
• Origin of indirect optical transitions in few-layer MoS2, WS2 and WSe2
• Photocarrier relaxation in two-dimensional semiconductors
• Electrical control of the valley Hall effect in bilayer MoS2 transistors
• Indirect-to-direct band-gap crossover in few-layer MoTe${}_2$
• Valley dynamics probed through charged and neutral exciton emission in monolayer WSe2
• Carrier and polarization dynamics in monolayer MoS2
• Identification of excitons, trions and biexcitons in single-layer WS2
• Atomically thin quantum light emitting diodes
• WSe2 light-emitting tunneling transistors with enhanced brightness at room temperature
• Brightening of dark excitons in monolayers of semiconducting transition metal dichalcogenides
• Optical properties of atomically thin transition metal dichalcogenides: Observations and puzzles
• Spin-orbit engineering in transition metal dichalcogenide alloy monolayers
• Exciton band structure in layered MoSe2: from a monolayer to the bulk limit
• Polarization and time-resolved photoluminescence spectroscopy of excitons in MoSe2 monolayers
• Excitonic valley effects in monolayer WS${}_2$ under high magnetic fields
• Cascaded emission of single photons from the biexciton in monolayered WSe2
• Nonlinear valley and spin currents from Fermi pocket anisotropy in 2D crystals
• Three-particle Complexes in Two-Dimensional Semiconductors
• Raman scattering excitation spectroscopy in monolayer WS${}_2$
• Electrically pumped single-defect light emitters in WSe${}_2$
• Exciton states in monolayer MoSe2: impact on interband transitions
• Excitonic properties of semiconducting monolayer and bilayer MoTe2
• Direct versus indirect band gap emission and exciton-exciton annihilation in atomically thin molybdenum ditelluride (MoTe${}_2$)
• Ultra-low power threshold for laser induced changes in optical properties of 2D Molybdenum dichalcogenides
• Well separated trion and neutral excitons on superacid treated MoS2 monolayers
• Sub-bandgap voltage electroluminescence and magneto-oscillations in a WSe2 light-emitting van der Waals heterostructure
• Revealing the nature of excitons in liquid exfoliated monolayer WS2
• Observation of three-particle complexes in WS${}_2$ monolayers

Cited by in corpus (38)

• Atomically thin quantum light emitting diodes
• Strong light-matter interaction with self-hybridized bound states in the continuum in monolithic van der Waals metasurfaces
• Interlayer excitons in bilayer MoS2 with strong oscillator strength up to room temperature
• Energy spectrum of two-dimensional excitons in a non-uniform dielectric medium
• Singlet and triplet trions in WS${}_2$ monolayer encapsulated in hexagonal boron nitride
• Dynamical screening in monolayer transition-metal dichalcogenides and its manifestations in the exciton spectrum
• Dark trions govern the temperature-dependent optical absorption and emission of doped atomically thin semiconductors
• Excitonic complexes in $n$-doped WS${}_2$ monolayer
• Magnetooptics of layered two-dimensional semiconductors and heterostructures: progress and prospects
• Fine structure of $\mathrm{K}$-excitons in multilayers of transition metal dichalcogenides
• Neutral and charged dark excitons in monolayer WS${}_2$
• Layer degree of freedom for excitons in transition metal dichalcogenides
• Zeeman spectroscopy of excitons and hybridization of electronic states in few-layer WSe${}_2$, MoSe${}_2$ and MoTe${}_2$
• Stacking-dependent exciton multiplicity in WSe${}_2$ bilayers
• Tuning carrier concentration in a superacid treated MoS${}_2$ monolayer
• Phonon-assisted exciton and trion conversion efficiency in transition metal Dichalcogenides
• Exciton-polaritons in multilayer WSe${}_2$ in a planar microcavity
• Charged exctions in two-dimensional transition-metal dichalcogenides - semiclassical calculation of Berry-curvature effects
• Anisotropic Optical And Vibrational Properties Of GeS
• Valley polarization of singlet and triplet trions in WS${}_2$ monolayer in magnetic fields
• Signatures of sub-band excitons in few-layer black phosphorus
• Controlling valley splitting and Polarization of dark- and bi-excitons in monolayer WS${}_2$ by a tilted magnetic field
• Raman scattering from the bulk inactive out-of-plane B${}_{2\text{g}}^1$ mode in few-layer MoTe${}_2$
• The optical response of artificially twisted MoS${}_2$ bilayers
• Impacts of dielectric screening on the luminescence of monolayer WSe${}_2$
• Anisotropic complex refractive indices of atomically thin materials: determination of the optical constants of few-layer black phosphorus
• Excitons and trions in WSSe monolayers
• Indium selenides for next-generation low-power computing devices
• Analogy and dissimilarity of excitons in monolayer and bilayer of MoSe${}_2$
• Raman scattering excitation in monolayers of semiconducting transition metal dichalcogenides
• Flattening conduction and valence bands for interlayer excitons in a moiré MoS${}_2$/WSe${}_2$ heterobilayer
• Morphology-induced spectral modification of self-assembled WS2 pyramids
• Symmetric Domain Segmentation in WS2 Flakes: Correlating spatially resolved photoluminescence, conductance with valley polarization
• Extremely high excitonic $g$-factors in 2D crystals by alloy-induced admixing of band states
• Optical response of WSe${}_2$-based vertical tunneling junction
• Electrically modulated light-emitting diodes driven by resonant and antiresonant tunneling between Cr${}_2$Ge${}_2$Te${}_6$ electrodes
• Valley Emission and Upconversion in Isotopically Engineered Monolayer WS${}_2$ under Resonant Excitation
• Rydberg series of intralayer K-excitons in WSe${}_2$ multilayers