AVS 51st International Symposium
    Nanometer-scale Science and Technology Thursday Sessions
       Session NS2-ThA

Paper NS2-ThA7
The Role of Electrodeposited Metal Nanowires in Gas Sensing

Thursday, November 18, 2004, 4:00 pm, Room 213D

Session: Nanowires II
Presenter: B.J. Murray, University of California, Irvine
Authors: B.J. Murray, University of California, Irvine
E.C. Walter, University of California, Irvine
R.M. Penner, University of California, Irvine
Correspondent: Click to Email
It in unclear what role, if any, metal nanowires have to play in chemical sensing. While the literature is ripe with examples of sensors based on semiconductor nanowires, there have been very few examples using metal nanowires. For these investigations - silver, copper, gold, and platinum nanowires were prepared by Electrochemical Step Edge Decoration (ESED) on a graphite surface. These nanowires were polycrystalline, consisted of a 1-D array of fused particles 50 nm to 950 nm in diameter, and had lengths of 100 µm or more. The resistance of these metal nanowires was probed as a function of the concentration of a chemisorbing gas. Upon exposure to ammonia (NH@sub 3@), arrays of these "fused particle" wires showed a resistance increase, @DELTA@R/R@sub 0@, that was fast, large (up to 1,000%), and reversible. Compared to literature on thin metal film sensors, the response of these nanowire arrays was much larger than expected. We propose that the elements responsible for this response were concentrated at a small minority of locations along axis of the wires. This proposed model, the Chemically Responsive Interparticle Boundary (CRIB) model, will be discussed. Finally, the chemical structure of these elements has been investigated to determine the role, if any, of air oxidation on sensor function.