Direct Observation of Gate Tunable Dark Trions in Monolayer WSe2

Abstract

Spin-forbidden intravalley dark exciton in tungsten-based transition metal dichalcogenides (TMDCs), owing to its unique spin texture and long lifetime, has attracted intense research interest. Here, we show that we can control the dark exciton electrostatically by dressing it with one free electron or free hole, forming the dark trions. The existence of the dark trions is suggested by the unique magneto-photoluminescence spectroscopy pattern of the boron nitride (BN) encapsulated monolayer WSe2 device at low temperature. The unambiguous evidence of the dark trions is further obtained by directly resolving the radiation pattern of the dark trions through back focal plane imaging. The dark trions possess binding energy of ~ 15 meV, and it inherits the long lifetime and large g-factor from the dark exciton. Interestingly, under the out-of-plane magnetic field, dressing the dark exciton with one free electron or hole results in distinctively different valley polarization of the emitted phonon, a result of the different intervalley scattering mechanism for the electron and hole. Finally, the lifetime of the positive dark trion can be further tuned from ~ 50 to ~ 215 ps by controlling the gate voltage. The gate tunable dark trions ushers in new opportunities for excitonic optoelectronics and valleytronics.

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Cited by in corpus (31)

• Electroluminescence from multi-particle exciton complexes in transition metal dichalcogenide semiconductors
• Correlated interlayer exciton insulator in double layers of monolayer WSe2 and moiré WS2/WSe2
• Giant Valley-Zeeman Splitting from Spin-Singlet and Spin-Triplet Interlayer Excitons in WSe2/MoSe2 Heterostructure
• Multipath optical recombination of intervalley dark excitons and trions in monolayer WSe${}_2$
• Exciton g-factors in monolayer and bilayer WSe${}_2$ from experiment and theory
• Strain control of hybridization between dark and localized excitons in a 2D semiconductor
• Dark trions govern the temperature-dependent optical absorption and emission of doped atomically thin semiconductors
• Measurement of Conduction and Valence Bands g-factors in a Transition Metal Dichalcogenide Monolayer
• Excitonic complexes in $n$-doped WS${}_2$ monolayer
• Intrinsic Donor-Bound Excitons in Ultraclean Monolayer Semiconductors
• Magnetooptics of layered two-dimensional semiconductors and heterostructures: progress and prospects
• Relaxation and darkening of excitonic complexes in electrostatically-doped monolayer semiconductors: Roles of exciton-electron and trion-electron interactions
• Neutral and charged dark excitons in monolayer WS${}_2$
• Interaction-driven transport of dark excitons in 2D semiconductors with phonon-mediated optical readout
• Manipulation of Exciton Dynamics in Single-Layer WSe2 Using a Toroidal Dielectric Metasurface
• First principles coupled cluster theory of the electronic spectrum of the transition metal dichalcogenides
• Interplay of Excitonic Complexes in $p$-Doped WSe${}_2$ Monolayers
• Trion photoluminescence and trion stability in atomically thin semiconductors
• Radially polarized light beams from spin-forbidden dark excitons and trions in monolayer WSe${}_2$
• Lattice reconstruction in MoSe${}_2$-WSe${}_2$ heterobilayers synthesized by chemical vapor deposition
• Probing biexciton in monolayer WS${}_2$ through controlled many-body interaction
• The effect of dielectric environment on the brightening of neutral and charged dark excitons in WSe${}_2$ monolayer
• Trion-trion annihilation in monolayer WS${}_2$
• Interplay of energy and charge transfer in WSe2/CrSBr heterostructures
• Valley-mediated singlet- and triplet-polaron interactions and quantum dynamics in a doped WSe${}_2$ monolayer
• Raman scattering excitation in monolayers of semiconducting transition metal dichalcogenides
• Magneto-Optical Measurements of the Negatively Charged 2$s$ Exciton in WSe${}_2$
• Spin/Valley pumping of resident electrons in WSe2 and WS2 monolayers
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