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 NH3 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 NH3 at room temperature. There is a good linear correlation between the decreasing amplitude of conductance and the NH3 concentration, and the detection limit of 10ppm NH3 could be achieved.