Gate tunable dark trions in monolayer WSe${}_2$

Abstract

We report the observation and gate manipulation of intrinsic dark trions in monolayer WSe${}_2$. By using ultraclean WSe${}_2$ devices encapsulated by boron nitride, we directly resolve the weak photoluminescence of dark trions. The dark trions can be tuned continuously between negative and positive charged trions with electrostatic gating. We also reveal their spin triplet configuration and distinct valley optical emission by their characteristic Zeeman splitting under magnetic field. The dark trions exhibit large binding energy (14-16 meV). Their lifetime (~1.3 ns) is two orders of magnitude longer than the bright trion lifetime (~10 ps) and can be tuned between 0.4 to 1.3 ns by electrostatic gating. Such robust, optically detectable, and gate tunable dark trions provide a new path to realize electrically controllable trion transport in two-dimensional materials.

26 pages, 16 figures

References in corpus (10)

• Valley polarization in MoS2 monolayers by optical pumping
• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• 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
• Breaking of valley degeneracy by magnetic field in monolayer MoSe2
• Valley Splitting and Polarization by the Zeeman Effect in Monolayer MoSe2
• Trion induced negative photoconductivity in monolayer MoS2
• Many-Body Theory of Trion Absorption Features in Two-Dimensional Semiconductors
• Brightening of dark excitons in monolayers of semiconducting transition metal dichalcogenides

Cited by in corpus (15)

• Valley Phonons and Exciton Complexes in a Monolayer Semiconductor
• Momentum-Dark Intervalley Exciton in Monolayer Tungsten Diselenide Brightened via Chiral Phonon
• Multipath optical recombination of intervalley dark excitons and trions in monolayer WSe${}_2$
• Exciton optics, dynamics and transport in atomically thin semiconductors
• Excitonic complexes in $n$-doped WS${}_2$ monolayer
• Intrinsic Donor-Bound Excitons in Ultraclean Monolayer Semiconductors
• Valley relaxation of resident electrons and holes in a monolayer semiconductor: Dependence on carrier density and the role of substrate-induced disorder
• Landau-quantized excitonic absorption and luminescence in a monolayer valley semiconductor
• Up- and Down-Conversion between Intra- and Inter-Valley Excitons in Waveguide Coupled Monolayer WSe2
• Probing biexciton in monolayer WS${}_2$ through controlled many-body interaction
• Excited-State Trions in Two Dimensional Materials
• The effect of dielectric environment on the brightening of neutral and charged dark excitons in WSe${}_2$ monolayer
• Trion-trion annihilation in monolayer WS${}_2$
• Doping-induced non-Markovian interference causes excitonic linewidth broadening in monolayer WSe${}_2$
• Radiative Decay of Dark Exciton Related Emission in a Sandwiched Monolayer WSe2 Revealed by Room Temperature Micro and Nano Photoluminescence