Understanding the Effects of Dielectric Property, Separation Distance, and Band Alignment on Interlayer Excitons in 2D Hybrid MoS2/WSe2 Heterostructures

Abstract

Two dimensional (2D) van der Waals heterostructures from transition metal dichalcogenide (TMDC) semiconductors show a new class of spatially separate excitons with extraordinary properties. The interlayer excitons (XI) have been studied extensively, yet the mechanisms that modulate XI are still not well understood. Here, we introduce several organic-layer-embedded hybrid heterostructures, MoS2/organic/WSe2, to study the binding energy of XI. We discover that the dielectric screening of the quasi-particle is reduced with organic molecules due to decreased dielectric constant and greater separation distance between the TMDC layers. As a result, a distinct blueshift is observed in interlayer emission. We also find that the band alignment at the heterointerface is critical. When the organic layer provides a staggered energy state, interlayer charge transfer can transition from tunneling to band-assisted transfer, further increasing XI emission energies due to a stronger dipolar interaction. The formation of XI may also be significantly suppressed with electron or hole trapping molecules. These findings should be useful in realizing XI-based optoelectronics.

References in corpus (17)

• Observation of Long-Lived Interlayer Excitons in Monolayer MoSe2-WSe2 Heterostructures
• Light-emitting diodes by bandstructure engineering in van der Waals heterostructures
• Measurement of the optical dielectric function of transition metal dichalcogenide monolayers: MoS2, MoSe2, WS2 and WSe2
• Strong interlayer coupling in van der Waals heterostructures built from single-layer chalcogenides
• Electroluminescence and photocurrent generation from atomically sharp WSe2/MoS2 heterojunction p-n diodes
• Long-lived direct and indirect interlayer excitons in van der Waals heterostructures
• Anomalous Interlayer Exciton Diffusion in Twist-Angle-Dependent Moiré Potentials of WS${}_2$-WSe${}_2$ Heterobilayers
• Exciton condensate in semiconductor quantum well structures.
• The dielectric genome of van der Waals heterostructures
• Monolayer MoS2/GaAs heterostructure self-driven photodetector with extremely high detectivity
• The dielectric impact of layer distances on exciton and trion binding energies in van der Waals heterostructures
• Exciton correlations in coupled quantum wells and their luminescence blue shift
• Observing imperfection in atomic interfaces for van der Waals heterostructures
• Interlayer excitons in transition metal dichalcogenide heterostructures
• Interlayer excitons in van der Waals heterostructures: Binding energy, Stark shift, and field-induced dissociation
• Upconverted electroluminescence via Auger scattering of interlayer excitons in van der Waals heterostructures
• Dielectric Engineering of Electronic Correlations in a van der Waals Heterostructure