Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 18: Plasmonics and Nanooptics II

O 18.8: Vortrag

Montag, 14. März 2011, 19:00–19:15, PHY C213

Fabrication of nanocone arrays for high sensitivity biosensing — •Monika Fleischer, Christian Schäfer, Andreas Horrer, Katharina Broch, Dominik Gollmer, Frank Schreiber, and Dieter P. Kern — Institut für Angewandte Physik, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 10, D- 72076 Tübingen

Plasmonic nanostructures, when resonantly interacting with an electromagnetic field, act as optical antennas focusing light to nanoscale volumes. Extremely high near-field enhancement is observed in the direct vicinity of the nanostructure surface, in particular at edges, corners, or tips. A process was developed for the fabrication of metallic nanocones with tip radii on the order of 10 nm. The cones are demonstrated to be efficiently excited by electric field components polarized parallel to the cone axis [1,2]. A narrow spot of high electric field strength is created near each cone apex due to the occurrence of localized surface plasmon resonances. Both serial and parallel methods for the fabrication of regular arrays of nanocones made from e.g. gold, silver, and copper are presented. Dense arrays of metal cones constitute a highly favorable system for high sensitivity sensing of biological or other organic molecules. For molecules located near a cone apex, strong Raman intensity enhancement is observed, similar to the effect of tip-enhanced Raman spectroscopy. This is demonstrated by the example of pentacene molecules [3] on gold cones.

[1] M. Fleischer et al., Nanotechnology 21, 065301 (2010)

[2] M. Fleischer et al., Appl. Phys. Lett. 93, 111114 (2008)

[3] A. Hinderhofer et al., J. Chem. Phys. 127, 194705 (2007)