The role of momentum-dark excitons in the elementary optical response of bilayer WSe${}_2$

Abstract

Monolayer (ML) transition metal dichalcogenides (TMDs) undergo substantial changes in the single-particle band structure and excitonic optical response upon the addition of just one layer. As opposed to the single-layer limit, the bandgap of bilayer (BL) TMD semiconductors is indirect which results in reduced photoluminescence with richly structured spectra that have eluded a detailed understanding to date. Here, we provide a closed interpretation of the elementary optical responses of BL WSe${}_2$ as a representative material for the wider class of TMD semiconductors. By combining theoretical calculations with comprehensive spectroscopy experiments, we identify the crucial role of momentum-indirect excitons for the understanding of basic absorption and emission spectra ubiquitously exhibited by various TMD BLs. Our results shed light on the origin of quantum dot (QD) formation in monolayer and bilayer crystals and will facilitate further advances directed at opto-electronic applications of layered TMD semiconductors in van der Waals heterostructures and devices.

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Cited by in corpus (50)

• Directly visualizing the momentum forbidden dark excitons and their dynamics in atomically thin semiconductors
• Enhanced Light-Matter Interaction in Two-Dimensional Transition Metal Dichalcogenides
• Phonon-assisted Photoluminescence from Dark Excitons in Monolayers of Transition Metal Dichalcogenides
• Electrically tunable valley dynamics in twisted WSe${}_2$/WSe${}_2$ bilayers
• Interlayer excitons in bilayer MoS2 with strong oscillator strength up to room temperature
• Giant Stark splitting of an exciton in bilayer MoS${}_2$
• Exciton g-factors of van der Waals heterostructures from first principles calculations
• Filtering the photoluminescence spectra of atomically thin semiconductors with graphene
• Hartree-Fock study of the moiré Hubbard model for twisted bilayer transition metal dichalcogenides
• Electrical control of hybrid exciton transport in a van der Waals heterostructure
• Bright single photon emitters with enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric nano-antennas
• Multipath optical recombination of intervalley dark excitons and trions in monolayer WSe${}_2$
• Moiré excitons in MoSe${}_2$-WSe${}_2$ heterobilayers and heterotrilayers
• Cavity-control of bright and dark interlayer excitons in van der Waals heterostructures
• Exciton g-factors in monolayer and bilayer WSe${}_2$ from experiment and theory
• Hybridized intervalley moiré excitons and flat bands in twisted WSe${}_2$ bilayers
• Exciton optics, dynamics and transport in atomically thin semiconductors
• Theory of exciton dynamics in time-resolved ARPES: intra- and intervalley scattering in two-dimensional semiconductors
• Long-range transport of 2D excitons with acoustic waves
• Observation of flat $\Gamma$ moiré bands in twisted bilayer WSe${}_2$
• Dielectric nano-antennas for strain engineering in atomically thin two-dimensional semiconductors
• Brightening of spin- and momentum-dark excitons in transition metal dichalcogenides
• Phonon-assisted inter-valley scattering determines ultrafast exciton dynamics in MoSe${}_2$ bilayers
• Dark-exciton driven energy funneling into dielectric inhomogeneities in two-dimensional semiconductors
• Ultrafast dynamics of bright and dark excitons in monolayer WSe${}_2$ and heterobilayer WSe${}_2$/MoS${}_2$
• Stacking-dependent exciton multiplicity in WSe${}_2$ bilayers
• Quenching of Intervalley Exchange Coupling in the Presence of Momentum-Dark States in TMDCs
• Spatially indirect intervalley excitons in bilayer WSe2
• Dark-exciton based strain sensing in transition metal dichalcogenides
• Probing correlations in the exciton landscape of a moiré heterostructure
• Exciton-polaritons in multilayer WSe${}_2$ in a planar microcavity
• Exploration of the bright and dark exciton landscape and fine structure of MoS${}_2$ (using G${}_0$W${}_0$-BSE)
• Impact of dark excitons on Förster type resonant energy transfer between dye molecules and atomically thin semiconductors
• Radially polarized light beams from spin-forbidden dark excitons and trions in monolayer WSe${}_2$
• Magnetoexcitons in transition-metal dichalcogenides monolayers, bilayers, and van der Waals heterostructures
• Electrically tunable dipolar interactions between layer-hybridized excitons
• Ultrafast pseudospin quantum beats in multilayer WSe${}_2$ and MoSe${}_2$
• Tuning exciton complexes in twisted bilayer WSe2 at intermediate misorientation
• Ultrafast Hidden Spin Polarization Dynamics of Bright and Dark Excitons in 2H-WSe${}_2$
• Probing excitons with time-resolved momentum microscopy
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• Electric-field-tunable intervalley excitons and phonon replicas in bilayer WSe${}_2$
• Brightening dark excitons and trions in systems with a Mexican-hat energy dispersion: example of InSe
• Spectral asymmetry of phonon sideband luminescence in monolayer and bilayer WSe2
• Strong Exciton-Photon Coupling in Large Area MoSe${}_2$ and WSe${}_2$ Heterostructures Fabricated from Two-Dimensional Materials Grown by Chemical Vapor Deposition
• Measurements of absolute bandgap deformation-potentials of optically-bright bilayer WSe${}_2$
• Robust Interlayer Exciton Interplay in Twisted van der Waals Heterotrilayer on a Broadband Bragg Reflector up to Room Temperature
• Tunable phononic coupling in excitonic quantum emitters
• Emergence of non-uniform strain induced exciton species in homo- and heterobilayer transition metal dichalcogenides