Exciton and trion dynamics in atomically thin MoSe2 and WSe2: effect of localization

Abstract

We present a detailed investigation of the exciton and trion dynamics in naturally doped MoSe2 and WSe2 single atomic layers as a function of temperature in the range 10-300K under above band-gap laser excitation. By combining time-integrated and time-resolved photoluminescence (PL) spectroscopy we show the importance of exciton and trion localization in both materials at low temperatures. We also reveal the transition to delocalized exciton complexes at higher temperatures where the exciton and trion thermal energy exceeds the typical localization energy. This is accompanied with strong changes in PL including suppression of the trion PL and decrease of the trion PL life-time, as well as significant changes for neutral excitons in the temperature dependence of the PL intensity and appearance of a pronounced slow PL decay component. In MoSe2 and WSe2 studied here, the temperatures where such strong changes occur are observed at around 100 and 200 K, respectively, in agreement with their inhomogeneous PL linewidth of 8 and 20 meV at T~10K. The observed behavior is a result of a complex interplay between influences of the specific energy ordering of bright and dark excitons in MoSe2 and WSe2, sample doping, trion and exciton localization and various temperature-dependent non-radiative processes.

References in corpus (25)

• Atomically thin MoS2: A new direct-gap semiconductor
• Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides
• Exciton Binding Energy and Nonhydrogenic Rydberg Series in Monolayer WS2
• Light-emitting diodes by bandstructure engineering in van der Waals heterostructures
• Electrical Control of Two-Dimensional Neutral and Charged Excitons in a Monolayer Semiconductor
• Solar-energy conversion and light emission in an atomic monolayer p-n diode
• Tightly bound excitons in monolayer WSe2
• Probing Excitonic Dark States in Single-layer Tungsten Disulfide
• Magnetic Control of Valley Pseudospin in Monolayer WSe2
• Valley Zeeman Effect in Elementary Optical Excitations of a Monolayer WSe2
• Low-temperature photocarrier dynamics in monolayer MoS2
• Fermi polaron-polaritons in charge-tunable atomically thin semiconductors
• Valley Splitting and Polarization by the Zeeman Effect in Monolayer MoSe2
• Exciton Radiative Lifetime in Transition Metal Dichalcogenide Monolayers
• Valley dynamics probed through charged and neutral exciton emission in monolayer WSe2
• Carrier and polarization dynamics in monolayer MoS2
• Exciton-exciton annihilation in MoSe2 monolayers
• WSe2 light-emitting tunneling transistors with enhanced brightness at room temperature
• Nonlinear Photoluminescence in Atomically Thin Layered WSe2 Arising from Diffusion-Assisted Exciton-Exciton Annihilation
• Trion Formation Dynamics in Monolayer Transition Metal Dichalcogenides
• Exciton band structure in layered MoSe2: from a monolayer to the bulk limit
• Polarization and time-resolved photoluminescence spectroscopy of excitons in MoSe2 monolayers
• Polarization analysis of excitons in monolayer and bilayer transition-metal dichalcogenides
• Magneto-optics in transition metal diselenide monolayers
• Tuning valley polarization in a WSe2 monolayer with a tiny magnetic field

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• Interplay between spin proximity effect and charge-dependent exciton dynamics in MoSe${}_2$ / CrBr${}_3$ van der Waals heterostructures
• Bright single photon emitters with enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric nano-antennas
• Dark excitons and the elusive valley polarization in transition metal dichalcogenides
• Exciton optics, dynamics and transport in atomically thin semiconductors
• Dynamical screening in monolayer transition-metal dichalcogenides and its manifestations in the exciton spectrum
• Exciton-Phonon Coupling and Band-Gap Renormalization in Monolayer WSe${}_2$
• Virtual trions in the photoluminescence of monolayer transition-metal dichalcogenides
• Spin States Protected from Intrinsic Electron-Phonon-Coupling Reaching 100 ns Lifetime at Room Temperature in MoSe${}_2$
• Few-body systems in condensed matter physics
• Non equilibrium anisotropic excitons in atomically thin ReS${}_2$
• Charged exciton kinetics in monolayer MoSe${}_2$ near ferroelectric domain walls in periodically poled LiNbO${}_3$
• Ultrafast photocurrents in MoSe${}_2$ probed by terahertz spectroscopy
• Phonon-assisted exciton and trion conversion efficiency in transition metal Dichalcogenides
• Inter-layer charge transport controlled by exciton-trion coherent coupling
• Valley Dynamics of Excitons in Monolayer Dichalcogenides
• Resonantly excited exciton dynamics in two-dimensional MoSe${}_2$ monolayers
• Long-lived spin polarization in n-doped MoSe${}_2$ monolayers
• Excitonic theory of doping-dependent optical response in atomically thin semiconductors
• Optical fingerprint of bright and dark localized excitonic states in atomically thin 2D materials
• Gate-tunable trion switch for excitonic device applications
• Magnetic field control of light-induced spin accumulation in monolayer MoSe${}_2$
• Photoluminescence kinetics of dark and bright excitons in atomically thin MoS${}_2$
• Magnetic Correlation Spectroscopy in CrSBr
• Nonexponential photoluminescence dynamics in an inhomogeneous ensemble of excitons in WSe${}_2$ monolayers
• Signatures of defect-localized charged excitons in the photoluminescence of monolayer molybdenum disulfide
• Trion confinement in monolayer MoSe2 by carbon nanotube local gating
• Room-Temperature Quantum-Confined Stark Effect in Atomically Thin Semiconductor
• Heteroepitaxial growth of high optical quality, wafer-scale van der Waals heterostrucutres
• Interface Dark Excitons at Sharp Lateral Two-Dimensional Heterostructures
• Enhanced Emission from WSe2 Monolayers Coupled to Circular Bragg Gratings
• Coherence and density dynamics of excitons in a single-layer MoS${}_2$ reaching the homogeneous limit