|Title||Nanoscale mapping of plasmon and exciton in ZnO tetrapods coupled with Au nanoparticles|
|Publication Type||Journal Article|
|Year of Publication||2016|
|Authors||Bertoni, G, Fabbri, F, Villani, M, Lazzarini, L, Turner, S, Van Tendeloo, G, Calestani, D, Gradecak, S, Zappettini, A, Salviati, G|
|Keywords||band-gap emission, Cathodoluminescence, energy-loss spectroscopy, enhancement, gold nanoparticles, nanorods, nanostructures, photochemical-synthesis, rapid synthesis, silver nanoparticles|
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 (similar to 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.
|Short Title||Sci Rep|