Berlin 2005 – wissenschaftliches Programm

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M: Metallphysik

M 28: Elektronische Eigenschaften

M 28.1: Vortrag

Montag, 7. März 2005, 10:30–10:45, TU H2038

Surface Plasmon Resonance of Ag Nanotubes — •Yun Luo¹, Yixin Zhang², Martin Steinhart¹, Ralf B. Wehrspohn³, Gunter Fischer² und Ulrich Gösele¹ — ¹Max-Planck-Institute of Microstructure Physics, Halle/Saale, Germany — ²Max-Planck Research Unit for Enzymology of Protein Folding, Halle/Saale, Germamy — ³Universität Paderborn, Warburger Strasse 100, Paderborn, Germany

Ag nanotubes and nanowires with outer diameters ranging from 25 nm to 400 nm and a shell thickness of 40 nm (in the case of tubes) have been fabricated via wetting of porous alumina templates and a subsequent annealing step at 350^∘C. Released nanotubes or nanowires with various diameters can be obtained by selectively removing the template.

In order to investigate the optical absorption properties of the 1D Ag nano-objects, they were dispersed in de-ionized water and placed in the beam path of a Hewlett-Packard Visible-ultraviolet spectrometer. During the measurement, the nanoobjects were kept suspended by stirring. The experimental absorption spectra carried out showed a sharp peak for Ag nanowires with a diameter of 25 nm at 374 nm. The peak position was shifted to longer wavelength and broadened when the diameter of the nanotubes was increasing.

FDTD calculations on both the transmission as well as the field distributions in the objects were performed assuming a dielectric constant corresponding to that of flat thin films. The calculated results show an agreement with the experiments curves