Interlayer Excitonic Spectra of Vertically Stacked MoSe<sub>2</sub>/WSe<sub>2</sub> Heterobilayers

Gillen, Roland

doi:10.1002/pssb.202170031

Cited by 4 publications

(2 citation statements)

References 87 publications

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“…Thus, the twist angle alignment and resultant interlayer distance controls the interlayer coupling strength as well as interlayer charge transfer [12,33]. Furthermore, increasing the layer separation with increasing twist angle decreases the electron and hole wavefunction overlap leading to reduced interlayer coupling strength and IX population [34].…”

Section: Twist Angle-dependent Anomalous Optical Responsementioning

confidence: 99%

Anomalous redshift in interlayer exciton emission with increasing twist angle in WSe₂/MoSe₂ heterostructures

Palekar,

Hagel,

Rosa

et al. 2024

2D Mater.

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Van der Waals heterostructures utilizing semiconducting transition metal dichalcogenide (TMDC) monolayers have surfaced as compelling candidates due to their intriguing optical characteristics, which can be effectively controlled by the manipulation of the stacking twist angle. This study investigates the intricate correlation between twist angle, band offset, and interlayer exciton emission within twisted WSe2/MoSe2 heterostructures. Our findings suggest a crucial influence of monolayer stacking order on the band offset and the dipole orientation in twisted heterostructures that leads to either blueshift or redshift in emission energy. Herein, we fabricate heterobilayers with twist angles varying from 1° to 56° and observe an anomalous redshift energy of 100 meV in the interlayer exciton emission. Additionally, photoluminescence excitation spectroscopy measurements highlight the systematic twist angle dependence of intralayer exciton resonances, indicating significant angle dependent effects on individual monolayer bandgaps and on the interlayer coupling strength. Our fundamental study of exciton resonances provides comprehensive insights into the nuanced interplay between twist angle, dipole orientation, and dielectric asymmetry, providing a deeper understanding of the factors governing the optical properties of layered TMDC heterostructures.

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Section: Twist Angle-dependent Anomalous Optical Responsementioning

confidence: 99%

Anomalous redshift in interlayer exciton emission with increasing twist angle in WSe₂/MoSe₂ heterostructures

Palekar,

Hagel,

Rosa

et al. 2024

2D Mater.

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“…This leads to the formation of tightly bound excitons with typical binding energies of 0.3-0.7 eV [5][6][7][8][9][10] , which dominate the optical properties of monolayer TMDs at both cryogenic and room temperatures 11 . Moreover, monolayer TMDs exhibit a rich excitonic spectrum featured by A and B excitons in lower-energy regime due to strong spin-orbit coupling of heavy TM atoms [12][13][14][15][16] and by C excitons in higher-energy regime due to high joint density of states induced by band nesting in the Brillouin zone [17][18][19] . In parallel, other exciton complexes, such as charged excitons (trions) and biexcitons have also been investigated [20][21][22][23][24][25] .…”

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confidence: 99%

Strain tunable interlayer and intralayer excitons in vertically stacked MoSe2/WSe2 heterobilayers

Gillen

Palummo³

et al. 2023

Applied Physics Letters

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Recently, interlayer and intralayer excitons in transition metal dichalcogenide heterobilayers have been studied both experimentally and theoretically. In spite of a growing interest, these layer-resolved excitons in the presence of external stimuli, such as strain, remain not fully understood. Here, using density-functional theory calculations with many-body effects, we explore the excitonic properties of vertically stacked MoSe2/WSe2 heterobilayer in the presence of in-plane biaxial strain of up to 5%. We calculate the strain dependence of exciton absorption spectrum, oscillator strength, wave function, and binding energy by solving the Bethe–Salpeter equation on top of the standard GW approach. We identify the interlayer and intralayer excitons by analyzing their electron-hole weights and spatial wave functions. We show that with the increase in strain magnitude, the absorption spectrum of the interlayer and intralayer excitons is red-shifted and re-ordered, and the binding energies of these layer-resolved excitons decrease monotonically and almost linearly. We derive the sensitivity of exciton binding energy to the applied strain and find that the intralayer excitons are more sensitive to strain than the interlayer excitons. For instance, a sensitivity of −7.9 meV/% is derived for the intra-MoSe2-layer excitons, which is followed by −7.4 meV/% for the intra-WSe2-layer excitons, and by −4.2 meV/% for the interlayer excitons. Our results indicate that interlayer and intralayer excitons in vertically stacked MoSe2/WSe2 heterobilayer are efficiently tunable by in-plane biaxial strain.

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Two dimensional semiconductors: Optical and electronic properties

Rosati,

Paradisanos,

Malic

et al. 2024

Reference Module in Materials Science and Materials Engineering

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Interlayer Excitonic Spectra of Vertically Stacked MoSe₂/WSe₂ Heterobilayers

Cited by 4 publications

References 87 publications

Anomalous redshift in interlayer exciton emission with increasing twist angle in WSe₂/MoSe₂ heterostructures

Anomalous redshift in interlayer exciton emission with increasing twist angle in WSe₂/MoSe₂ heterostructures

Strain tunable interlayer and intralayer excitons in vertically stacked MoSe2/WSe2 heterobilayers

Two dimensional semiconductors: Optical and electronic properties

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Interlayer Excitonic Spectra of Vertically Stacked MoSe2/WSe2 Heterobilayers

Cited by 4 publications

References 87 publications

Anomalous redshift in interlayer exciton emission with increasing twist angle in WSe2/MoSe2 heterostructures

Anomalous redshift in interlayer exciton emission with increasing twist angle in WSe2/MoSe2 heterostructures

Strain tunable interlayer and intralayer excitons in vertically stacked MoSe2/WSe2 heterobilayers

Two dimensional semiconductors: Optical and electronic properties

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Product

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Interlayer Excitonic Spectra of Vertically Stacked MoSe₂/WSe₂ Heterobilayers

Anomalous redshift in interlayer exciton emission with increasing twist angle in WSe₂/MoSe₂ heterostructures

Anomalous redshift in interlayer exciton emission with increasing twist angle in WSe₂/MoSe₂ heterostructures