A carbon nanotube gas sensor fabricated by dielectrophoresis and its application for NH3 detection.

Multi-walled carbon nanotubes (MWNTs) were successfully manipulated by dielectrophoresis (DEP) to form electrical connection between interdigitated gold electrodes (IDEs) and were demonstrated to serve as gas sensor for NH(3) detection. The MWNTs were suspended in ethanol and deposited on the IDEs under the effect of DEP. After the evaporation of ethanol, the MWNTs remained between the gaps of the IDEs. The electrical conductivity of the DEP-fabricated MWNTs sensor decreased when exposed to NH(3) at room temperature. There is a good linear correlation between the decreasing amplitude of conductance and the NH(3) concentration, and the detection limit of 10 ppm NH(3) could be achieved.