Improved Chemical Detection using Single-walled Carbon Nanotube Network Capacitors
NAVAL RESEARCH LAB WASHINGTON DC
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We explore capacitance- and conductance-based detection of trace chemical vapors using single-walled carbon nanotubes SWNTs. We find that conductance detection is susceptible to such problems as large 1f noise and incomplete sensor recovery, which are primarily artifacts of a charge-based transduction mechanism. Capacitance detection, dominated by dielectric effects, is less sensitive to charge effects and, thus, offers increased signal-to-noise ratio, improved sensor recovery, and larger dynamic range. Our data indicate capacitance-based sensing with SWNTs is well suited for trace-level detection of such low-vapor-pressure materials as certain chemical warfare agents and explosives.
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