AVS 58th Annual International Symposium and Exhibition
    Nanometer-scale Science and Technology Division Tuesday Sessions
       Session NS-TuP

Paper NS-TuP1
Electromigration Assisted Single Silver Nanowire Ammonia Sensing

Tuesday, November 1, 2011, 6:00 pm, Room East Exhibit Hall

Session: Nanometer-scale Science and Technology Division Poster Session
Presenter: Wendong Xing, University of California, Irvine
Authors: W. Xing, University of California, Irvine
S. Kung, University of California, Irvine
R. Penner, University of California, Irvine
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Due to small size, high sensitivity, and low power consumption, 1 dimensional nanowire sensors have attracted a lot of attention and may substitute for traditional thin film sensors in the future. To further improve the sensitivity, there is an obvious need to make sensors with a single nanowire and some seminal work has already been done using semiconductor nanowires in this direction. In this work, a single silver (Ag) nanowire was prepared on glass surface using Lithographically Patterned Nanowire Electrodeposition (LPNE) method. The produced Ag nanowire had a mean grain size of around 30nm and a height and width in the range from 20-80nm and 100-400nm, respectively. Chemiresistor type sensors were fabricated from these single electromigrated Ag nanowires with 4 probe contacts, and their resistances upon exposure to different concentrations of NH3 gas were investigated at room temperature. Furthermore, electromigration was used to create a narrow junction inside the nanowire, which enhanced the sensing performance dramatically. The eletromigrated sensors showed a resistance change, △R/Ro, that was large (90% for 7% NH3), fast (<30s) and reversible with a detection limit of approximately 200ppm. In addition, the characterization of these nanowires by AFM, TEM, and SEM will be presented.