Edge-Localized Plasmonic Resonances in WS2 Nanostructures from Electron Energy-Loss Spectroscopy.

Abstract

Localized plasmon resonances in 2D transition metal dichalcogenides (TMDs) offer a powerful means to enhance light-matter interactions at the nanoscale, making them ideal candidates for advanced optoelectronic applications. However, disentangling the complex plasmonic interactions in these materials, especially in the low-energy regime, presents significant challenges. Herein, localized plasmon resonances in chemical vapor deposition-grown tungsten disulfide (WS₂) nanotriangles, using a combination of advanced spectral analysis and simulation techniques, is investigated. By combining non-negative matrix factorization with electron energy loss spectroscopy, distinct plasmonic modes to provide a comprehensive analysis of the plasmonic landscape of individual and stacked WS₂ nanotriangles are identified and characterized. Furthermore, the dispersion relation of these localized plasmon resonances is quantified and their evolution across different WS₂ triangular geometries is evaluated. Experimental characterization of plasmonic resonances in WS₂ through dedicated numerical simulations based on the pygdm package is validated. The findings highlight the critical role of localized plasmon resonances in modulating the electronic and optical properties of WS₂, offering new insights into the design and optimization of TMD-based devices for optoelectronic and nanophotonic applications.