AVS 53rd International Symposium
    Nanometer-scale Science and Technology Friday Sessions
       Session NS-FrM

Paper NS-FrM4
Large Area, Dense Si Nanowire Array Chemical Sensors

Friday, November 17, 2006, 9:00 am, Room 2016

Session: Nanowires
Presenter: A.A. Talin, Sandia National Laboratories
Authors: A.A. Talin, Sandia National Laboratories
L.L. Hunter, Sandia National Laboratories
B. Rokad, Sandia National Laboratories
F. Leonard, Sandia National Laboratories
B.A. Simmons, Sandia National Laboratories
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We present a simple top down approach based on nanoimprint lithography to create dense arrays of silicon nanowires over large areas. Metallic contacts to the nanowires and a bottom gate allow the operation of the array as a field-effect transistor with very large on/off ratios. The carrier mobility extracted from transconductance measurement exceed the values reported for chemically synthesized Si nanowires with similar dimensions. When exposed to ammonia gas or cyclohexane solutions containing nitrobenzene or phenol, the threshold voltage of the field-effect transistor is shifted, a signature of charge transfer between the analytes and the nanowires. The threshold voltage shift is proportional to the Hammett parameter and the concentration of the nitrobenzene and phenol analytes. For the liquid analytes considered, we find binding energies of 400 meV, indicating strong physisorption. Such values of the binding energies are ideal for stable and reusable sensors.