Microsecond Valley Lifetime of Defect-Bound Excitons in Monolayer WSe${}_2$

Abstract

In atomically thin two-dimensional semiconductors such as transition metal dichalcogenides (TMDs), controlling the density and type of defects promises to be an effective approach for engineering light-matter interactions. We demonstrate that electron-beam irradiation is a simple tool for selectively introducing defect-bound exciton states associated with chalcogen vacancies in TMDs. Our first-principles calculations and time-resolved spectroscopy measurements of monolayer WSe2 reveal that these defect-bound excitons exhibit exceptional optical properties including a recombination lifetime approaching 200 ns and a valley lifetime longer than 1 $\mu$s. The ability to engineer the crystal lattice through electron irradiation provides a new approach for tailoring the optical response of TMDs for photonics, quantum optics, and valleytronics applications.

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Cited by in corpus (27)

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• Fabrication methods for integrating 2D materials
• Enhanced Light-Matter Interaction in Two-Dimensional Transition Metal Dichalcogenides
• Point Defects and Localized Excitons in 2D WSe2
• Momentum-Dark Intervalley Exciton in Monolayer Tungsten Diselenide Brightened via Chiral Phonon
• The bright side of defects in MoS${}_2$ and WS${}_2$ and a generalizable chemical treatment protocol for defect passivation
• Intrinsic and Extrinsic Defect-related Excitons in TMDCs
• Probing defects and spin-phonon coupling in CrSBr via resonant Raman scattering
• Identifying defect-related quantum emitters in monolayer WSe${}_2$
• Intrinsic Donor-Bound Excitons in Ultraclean Monolayer Semiconductors
• Spin-defect characteristics of single sulfur vacancies in monolayer ${\text{MoS}}_2$
• Unveiling valley lifetimes of free charge carriers in monolayer WSe${}_2$
• Unveiling Defect-Mediated Carrier Dynamics in Monolayer Semiconductors by Spatiotemporal Microwave Imaging
• Spin States Protected from Intrinsic Electron-Phonon-Coupling Reaching 100 ns Lifetime at Room Temperature in MoSe${}_2$
• Enhancement of Exciton Valley Polarization in Monolayer MoS2 Induced by Scattering
• Extrinsic localized excitons in patterned 2D semiconductors
• Twist angle dependent interlayer transfer of valley polarization from excitons to free charge carriers in WSe${}_2$/MoSe${}_2$ heterobilayers
• Ultrafast photocurrent and absorption microscopy of few-layer TMD devices isolate rate-limiting dynamics driving fast and efficient photoresponse
• Tunable magneto-optical properties in MoS${}_2$ via defect-induced exciton transitions
• Atomistic $T$-matrix theory of disordered 2D materials: Bound states, spectral properties, quasiparticle scattering, and transport
• Creation and Microscopic Origins of Single-Photon Emitters in Transition Metal Dichalcogenides and Hexagonal Boron Nitride
• Flat-band-induced many-body interactions and exciton complexes in a layered semiconductor
• Magnetically tunable exciton valley coherence in monolayer WS${}_2$ mediated by the electron-hole exchange and exciton-phonon interactions
• Effect of electron-irradiation on layered quantum materials
• Direct observation of ultrafast defect-bound and free exciton dynamics in defect-engineered WS${}_2$ monolayers
• Magnetic proximity coupling to defects in a two-dimensional semiconductor
• How the dynamic of photo-induced gate screening complicates the investigation of valley physics in 2D materials