Dresden 2006 – wissenschaftliches Programm

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SYNW: Nano Wires

SYNW 1: Symposium: Nano-Wires I

SYNW 1.1: Hauptvortrag

Mittwoch, 29. März 2006, 14:00–14:30, HSZ 04

Electrodeposition and Functional Properties of Metal Nanowires — •Reginald M. Penner and — Department of Chemistry, University of California, Irvine, CA 92697-2025 USA

Semiconductor nanowires can be used as transducer to detect the binding of charged analyte molecules. However in view of the frenzied pace of research relating to nanowires synthesis, remarkably few publications report advances in semiconductor nanowire-based sensing. Progress in this direction has been impeded by the intrinsic instability of semiconductor nanowires toward corrosion.

Noble metal nanowires are attractive candidates for chemical sensing. However, in contrast to semiconductor nanowires, the conductivity of metal nanowires is not expected to be responsive to ’charge gating’. We have developed a new method for preparing arrays of noble metal nanowires that involves the electrodeposition of metals onto stepped graphite surface and the transfer of arrays of wires onto glass surfaces using a simple embedding process. These transferred nanowires form the basis for chemical sensors in which the resistance of the nanowire array is modulated by molecules that chemisorb at the surface. Two examples involve palladium nanowires in the presence of hydrogen, and silver in the presence of amines. For both systems, the changes in resistance (△R/R0) can be 1000.

What is the origin of these unexpected resistance changes? We focus attention on this issue and we discuss the prospect for developing practical chemical sensors based on these novel mechanisms.