Nanoscale mapping of plasmon and exciton in ZnO tetrapods coupled with Au 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 nan...
Main Authors: | , , , , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Nature Publishing Group,
2016-03-18T16:18:05Z.
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Subjects: | |
Online Access: | Get fulltext |
Summary: | 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. Seventh Framework Programme (European Commission) (Grant Agreement n. 265073 ITN-Nanowiring) Seventh Framework Programme (European Commission) (Grant Agreement n. 312483 ESTEEM2 for Integrated Infrastructure Initiative - I3) United States. Dept. of Energy. Office of Basic Energy Sciences (Award DE-SC0001088) |
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