Regensburg 2007 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 31: New Materials
CPP 31.6: Talk
Friday, March 30, 2007, 11:45–12:00, H40
Fabrication of nano-porous electrode arrays by self-assembly — •Theobald Lohmüller1, Ulrich Müller2, Martin Stelzle2, Stephan Linke3, Markus Kaczor3, and Joachim Spatz1 — 1MPI für Metallforschung & Universität Heidelberg, 70569 Stuttgart — 2Naturwissenschaftliches und Medizinisches Institut, 72770 Reutlingen — 3HL Planartechnik GmbH, 44227 Dortmund
Colloidal particles are used as a lithographic tool for the fabrication of a nano-porous electrochemical sensor. The system consists of a bottom and a porous top electrode separated by an insulating layer of predefined thickness. Polystyrene particles of different sizes act as a shadow mask for the deposition of the top electrode. After the particle lift-off, the porous metal layer is used as an etching resist to remove the insulating material. By adjustment of the nanoelectrode spacing and its pore diameter defined electrode arrays are generated. We demonstrate the control of particle films with particle sizes up to 1 μm by a simple dipping procedure. This enables a fast and reproducible processing of a lithographic mask. The particle adsorption is influenced by electrostatic particle/particle and particle/surface interactions, resulting in an extended monolayer of ordered particles on the surface. In this context we present solutions how the pore size and spacing can be adjusted in order to improve the nanopore geometry. Enhanced electrochemical sensitivity is achieved by redox-cycling between the top and bottom electrode. So far, amplification factors > 50 have been demonstrated. Currently the system is optimized to obtain maximum signal amplification.