Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 59: Poster Session II (Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: arrays; Nanostructures at surfaces: Wires, tubes; Nanostructures at surfaces: Other; Plasmonics and nanooptics; Metal substrates: Epitaxy and growth; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsoprtion of organic / bio molecules; Metal substrates: Adsoprtion of inorganic molecules; Metal substrates: Adsoprtion of O and/or H; Metal substrates: Clean surfaces; Density functional theory and beyond for real materials)
O 59.6: Poster
Mittwoch, 24. März 2010, 17:45–20:30, Poster B1
Photoconductivity of metal nanoparticle ensembles supported by localized surface plasmon polariton resonances (LSPPRs) — •Elena Vashchenko1, Tigran Vartanyan2, Frank Träger1, and Frank Hubenthal1 — 1Universität Kassel, 34132 Kassel, Germany — 2SPbSU ITMO, 197101 Saint-Petersburg, Russia
Owing to their specific properties, various kinds of dispersive systems attract great interest of researchers. Intriguing examples of such systems are metal nanoparticle ensembles (MNEs), which exhibit superior optical properties. Recently, the electric properties of such MNEs have found increasing attention. MNEs represent interlinked systems, which can be used as light driven electric devices.
In this contribution we demonstrate a LSPPR driven photoconductivity in silver and sodium nanoparticle ensembles. For this purpose MNEs were prepared on dielectric substrates and afterwards characterized by extinction spectroscopy and atomic force microscopy. The extinction spectra of the MNEs showed pronounced LSPPRs at wavelengths below the threshold of the external photo effect in the corresponding bulk metal. Subsequently a voltage has been applied to the MNEs and the current has been measured. We found that the current through the illuminated MNEs is more than one order of magnitude higher compared to the current without illumination. The strongest increase is obtained for wavelengths that are in resonance with the LSPPR of the MNEs. A theoretical interpretation of the observed phenomena based on the reduction of the tunneling barrier for the photoexcited electrons is provided.