Nanoscale mapping of plasmon and exciton in ZnO tetrapods coupled with Au nanoparticles
Author(s)Bertoni, Giovanni; Fabbri, Filippo; Villani, Marco; Lazzarini, Laura; Turner, Stuart; Van Tendeloo, Gustaaf; Calestani, Davide; Gradecak, Silvija; Zappettini, Andrea; Salviati, Giancarlo; ... Show more Show less
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Metallic nanoparticles can be used to enhance optical absorption or emission in semiconductors, thanks to a strong interaction of collective excitations of free charges (plasmons) with electromagnetic fields. Herein we present direct imaging at the nanoscale of plasmon-exciton coupling in Au/ZnO nanostructures by combining scanning transmission electron energy loss and cathodoluminescence spectroscopy and mapping. The Au nanoparticles (~30 nm in diameter) are grown in-situ on ZnO nanotetrapods by means of a photochemical process without the need of binding agents or capping molecules, resulting in clean interfaces. Interestingly, the Au plasmon resonance is localized at the Au/vacuum interface, rather than presenting an isotropic distribution around the nanoparticle. On the contrary, a localization of the ZnO signal has been observed inside the Au nanoparticle, as also confirmed by numerical simulations.
DepartmentMassachusetts Institute of Technology. Department of Materials Science and Engineering
Nature Publishing Group
Bertoni, Giovanni, Filippo Fabbri, Marco Villani, Laura Lazzarini, Stuart Turner, Gustaaf Van Tendeloo, Davide Calestani, Silvija Gradecak, Andrea Zappettini, and Giancarlo Salviati. “Nanoscale Mapping of Plasmon and Exciton in ZnO Tetrapods Coupled with Au Nanoparticles.” Scientific Reports 6 (January 12, 2016): 19168.
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