Curvature-enhanced localised emission from dark states in wrinkled monolayer WSe2 at room temperature

Abstract

Localised emission from defect states in monolayer transition metal dichalcogenides is of great interest for optoelectronic and quantum device applications. Recent progress towards high temperature localised emission relies on the application of strain to induce highly confined excitonic states. Here we propose an alternative paradigm based on curvature, rather than in-plane stretching, achieved through free-standing wrinkles of monolayer tungsten diselenide (WSe2). We probe these nanostructures using tip-enhanced optical spectroscopy to reveal the spatial localisation of out-of-plane polarised emission from the WSe2 wrinkles. Based on the photoluminescence and Raman scattering signatures resolved with nanoscale spatial resolution, we propose the existence of a manifold of spin-forbidden excitonic states that are activated by the local curvature of the WSe2. We are able to access these dark states through the out-of-plane polarised surface plasmon polariton resulting in enhanced strongly localised emission at room temperature, which is of potential interest for quantum technologies and photonic devices.

References in corpus (12)

• Phonon and Raman scattering of two-dimensional transition metal dichalcogenides from monolayer, multilayer to bulk material
• Irradiation of Nanostrained Monolayer WSe${}_2$ for Site-Controlled Single-Photon Emission up to 150 K
• Imaging strain-localized exciton states in nanoscale bubbles in monolayer WSe2 at room temperature
• Strained bubbles in van der Waals heterostructures as local emitters of photoluminescence with adjustable wavelength
• Strain, doping and electronic transport of large area monolayer MoS2 exfoliated on gold and transferred to an insulating substrate
• Magneto-photoluminescence of exciton Rydberg states in monolayer WSe${}_2$
• Probing dark exciton navigation through a local strain landscape in a WSe${}_2$ monolayer
• Quantum-dot-like states in molybdenum disulfide nanostructures due to the interplay of local surface wrinkling, strain, and dielectric confinement
• The edge delamination of monolayer transition metal dichalcogenides
• Adaptive tip-enhanced nano-spectroscopy
• Dark-exciton driven energy funneling into dielectric inhomogeneities in two-dimensional semiconductors
• Direct Observation of Intravalley Phonon Scattering of 2s Excitons in MoSe${}_2$ and WSe${}_2$ Monolayers

Cited by in corpus (2)

• Absence of Weak Localization on Negative Curvature Surfaces
• Emergence of non-uniform strain induced exciton species in homo- and heterobilayer transition metal dichalcogenides