Coupling interlayer excitons to whispering gallery modes in van der Waals heterostructures

Abstract

Van der Waals heterostructures assembled from two-dimensional materials offer a promising platform to engineer structures with desired optoelectronic characteristics. Here we use waveguide-coupled disk resonators made of hexagonal boron nitride (h-BN) to demonstrate cavity-coupled emission from interlayer excitons of a heterobilayer of two monolayer transition metal dichalcogonides. We sandwich a MoSe${}_2$ - WSe${}_2$ heterobilayer between two slabs of h-BN and directly pattern the resulting stack into waveguide-coupled disk resonators. This enables us to position the active materials into regions of highest optical field intensity, thereby maximizing the mode overlap and the coupling strength. Since the interlayer exciton emission energy is lower than the optical band gaps of the individual monolayers and since the interlayer transition itself has a weak oscillator strength, the circulating light is only weakly reabsorbed, which results in an unaffected quality factor. Our devices are fully waveguide-coupled and represent a promising platform for on-chip van der Waals photonics.

Supplementary information included

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Cited by in corpus (7)

• Enhanced Light-Matter Interaction in Two-Dimensional Transition Metal Dichalcogenides
• All van der Waals Integrated Nanophotonics
• Atomic-Void van der Waals Channel Waveguides
• Microsphere-coupled light emission control of van der Waals heterostructures
• Engineering Purcell factor anisotropy for dark and bright excitons in two dimensional semiconductors
• Freeform nanostructuring of hexagonal boron nitride
• Integration of hBN quantum emitters in monolithically fabricated waveguides