Point defects in [Ca 2 Nb 3 O 10 ] − monolayers and intralayer excitons in [Ca 2 Nb 3 O 10 ] − /WSe 2 heterostructures
Year: 2026
Type: article
Abstract: We report the fabrication and atomic-scale characterization of a novel van der Waals heterostructure composed of monolayer WSe 2 and monolayer [Ca 2 Nb 3 O 10 ] - (CNO). Using 60kV Cc/Cs-corrected high-resolution transmission electron microscopy, we obtain atomic-resolution images of freestanding CNO monolayers, revealing their crystalline structure and beam-induced defect formation. Structure modeling, image simulations, and first-principles calculations point at the preferential oxygen and calcium vacancy formation under electron irradiation. Spatially resolved monochromated STEM-EELS analysis reveals a small but reproducible redshift (∼20 meV) of the D exciton of WSe 2 when covered by CNO, consistent with a weak interfacial modification of the local dielectric/electronic environment. Additional first-principles calculations indicate weak interfacial coupling and show that the electronic structure is highly sensitive to the charge-compensating environment of the CNO layer. Our findings demonstrate that functional oxide nanosheets can be integrated with transition metal dichalcogenide (TMD) monolayers to form oxide/TMD van der Waals heterostructures with locally modified excitonic properties, offering new opportunities for engineered 2D material systems.
Source: 2D Materials
Institutions: Universität Ulm, Center for Integrated Quantum Science and Technology, Humboldt-Universität zu Berlin, Helmholtz-Zentrum Dresden-Rossendorf, Max Planck Institute for Solid State Research, Ludwig-Maximilians-Universität München, Technische Universität Dresden, Center for Advanced Systems Understanding, University of Cambridge
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,895
OpenAlex ID: W7213899992