Exciton states in monolayer MoSe2: impact on interband transitions

Abstract

We combine linear and non-linear optical spectroscopy at 4K with ab initio calculations to study the electronic bandstructure of MoSe2 monolayers. In 1-photon photoluminescence excitation (PLE) and reflectivity we measure a separation between the A- and B-exciton emission of 220 meV. In 2-photon PLE we detect for the A- and B-exciton the 2p state 180meV above the respective 1s state. In second harmonic generation (SHG) spectroscopy we record an enhancement by more than 2 orders of magnitude of the SHG signal at resonances of the charged exciton and the 1s and 2p neutral A- and B-exciton. Our post-Density Functional Theory calculations show in the conduction band along the $K-\Gamma$ direction a local minimum that is energetically and in k-space close to the global minimum at the K-point. This has a potentially strong impact on the polarization and energy of the excitonic states that govern the interband transitions and marks an important difference to MoS2 and WSe2 monolayers.

8 pages, 3 figures

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• Fermi polaron-polaritons in charge-tunable atomically thin semiconductors
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• Enhanced Light-Matter Interaction in Two-Dimensional Transition Metal Dichalcogenides
• Optical harmonic generation in monolayer group-VI transition metal dichalcogenides
• Optical response of monolayer, few-layer and bulk tungsten disulfide
• Optical valley Hall effect for highly valley-coherent exciton-polaritons in an atomically thin semiconductor
• Discrete quantum dot like emitters in monolayer MoSe2: Spatial mapping, Magneto-optics and Charge tuning
• Engineering of Neutral Excitons and Exciton Complexes in Transition Metal Dichalcogenide Monolayers through External Dielectric Screening
• Guide to optical spectroscopy of layered semiconductors
• Excitonic properties of semiconducting monolayer and bilayer MoTe2
• Exciton states in monolayer MoSe2 and MoTe2 probed by upconversion spectroscopy
• Phonon-assisted oscillatory exciton dynamics in monolayer MoSe2
• Ground and Excited Exciton Polarons in Monolayer MoSe2
• Second harmonic generation control in twisted bilayers of transition metal dichalcogenides
• Optical Absorption by Dirac Excitons in Single-Layer Transition-Metal Dichalcogenides
• Spinorial formulation of the GW-BSE equations and spin properties of excitons in 2D Transition Metal Dichalcogenides
• Model Prediction of Self-Rotating Excitons in Two-Dimensional Transition-Metal Dichalcogenides
• Second- and third-order optical susceptibilities in bidimensional semiconductors near excitons states
• Role of Interlayer Coupling in the Second Harmonic Generation of Bilayer Transition-metal Dichalcogenides
• Direct Observation of Intravalley Phonon Scattering of 2s Excitons in MoSe${}_2$ and WSe${}_2$ Monolayers
• Ultra-compact photodetection in atomically thin MoSe${}_2$
• Phonon signatures in spectra of exciton polaritons in transition metal dichalcogenides
• Probing the optical near-field interaction of Mie nanoresonators with atomically thin semiconductors
• Modelling excitonic Mott transitions in two-dimensional semiconductors
• Engineering the Radiative Dynamics of Thermalized Excitons with Metal Interfaces
• Interlayer exciton mediated second harmonic generation in bilayer MoS2
• Phonon-induced Markovian and non-Markovian effects on absorption spectra of moiré excitons in twisted transition metal dichalcogenide bilayers