Dielectrophoresis Carbon Nanotube and Conductive Polyaniline Nanofiber NH3 Gas Sensor

Carbon nanotube and single polyaniline nanofiber gas sensors were investigated in this study. Carbon nanotube gas sensor was constructed by means of dielectrophoresis. Single nanofiber was deposited as nanofiber sensor across two gold electrodes by means of near-field electrospinning without conventional lithography process. The nanofiber sensor showed a 2.7% reversible resistance change to 1 ppm NH3 with a response time of 60 s. Carbon nanotube sensor showed good linearity in the concentration range above 20 ppm with response times between 100 and 200 s. The fibers with smaller diameter showed quicker response to NH3 on the basis of gas diffusion mechanism. As such, CNT sensor and nanofiber-based sensors could be promising for gas sensing array and multi-chemical sensing applications.