Exposing the trion's fine structure by controlling the carrier concentration in hBN-encapsulated MoS${}_2$

Abstract

Atomically thin materials, like semiconducting transition metal dichalcogenides, are highly sensitive to the environment. This opens up an opportunity to externally control their properties by changing their surroundings. In this work, high-quality van der Waals heterostructures assembled from hBN-encapsulated monolayer MoS${}_2$ are studied with the aid of photoluminescence, photoluminescence excitation, and reflectance contrast experiments. We demonstrate that carrier concentration in MoS${}_2$ monolayers, arising from charge transfer from impurities in the substrate, can be significantly tuned within one order of magnitude by the modification of the bottom hBN flake thickness. The studied structures, characterized by spectral lines approaching the narrow homogeneously broadened limit enabled observations of subtle optical and spin-valley properties of excitonic complexes. Our results allowed us to resolve three optically-active negatively charged excitons in MoS${}_2$ monolayers, which are assigned to the intravalley singlet, intervalley singlet, and intervalley triplet states.

9 pages, 4 figures

References in corpus (12)

• 2D materials and van der Waals heterostructures
• Integrated Circuits Based on Bilayer MoS2 Transistors
• Light-emitting diodes by bandstructure engineering in van der Waals heterostructures
• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Atomically thin boron nitride: a tunnelling barrier for graphene devices
• Towards Intrinsic Charge Transport in Monolayer Molybdenum Disulfide by Defect and Interface Engineering
• Chemical reactivity imprint lithography on graphene: Controlling the substrate influence on electron transfer reactions
• Twist-controlled resonant tunnelling in graphene-boron nitride-graphene heterostructures
• Optical spectroscopy of excited exciton states in MoS2 monolayers in van der Waals heterostructures
• Engineering of Neutral Excitons and Exciton Complexes in Transition Metal Dichalcogenide Monolayers through External Dielectric Screening
• Sub-bandgap voltage electroluminescence and magneto-oscillations in a WSe2 light-emitting van der Waals heterostructure
• Local photodoping in monolayer MoS2

Cited by in corpus (12)

• Trions in MoS${}_2$ are quantum superpositions of intra- and intervalley spin states
• Probing Dark Excitons in Monolayer MoS${}_2$ by NonLinear Two-Photon Spectroscopy
• The effect of dielectric environment on the brightening of neutral and charged dark excitons in WSe${}_2$ monolayer
• Quantum light generation with ultra-high spatial resolution in 2D semiconductors via ultra-low energy electron irradiation
• Proximity-enhanced valley Zeeman splitting at the WS${}_2$/graphene interface
• Raman scattering excitation in monolayers of semiconducting transition metal dichalcogenides
• Electrostatic control of the trion fine structure in transition metal dichalcogenide monolayers
• Energy shifts and broadening of excitonic resonances in electrostatically-doped semiconductors
• Extremely high excitonic $g$-factors in 2D crystals by alloy-induced admixing of band states
• Magneto-Excitonic Duality From Monolayer to Trilayer CrSBr
• Electrically modulated light-emitting diodes driven by resonant and antiresonant tunneling between Cr${}_2$Ge${}_2$Te${}_6$ electrodes
• Efficient valley polarization of charged excitons and resident carriers in MoS2 monolayers by optical pumping