NO sensing property of carbon nanotube based thin film gas sensors prepared by chemical vapor deposition techniques

To prepare a gas sensor that can operate at room temperature, carbon nanotubes (CNTs) were grown on Al2O3 substrates with interdigital Pt electrodes (Al2O3 substrate) by both pulsed laser deposition (PLD) and chemical vapor deposition (CVD). In this combined method, Fe catalytic thin film was prepared by PLD and then CNTs were grown on the Fe thin film by thermal CVD using an ethylene gas. The surface images of the prepared CNTs on the substrates were observed by scanning electron microscopy (SEM), and the sensitivity to NO gas was measured. The resistance of the prepared CNT-based gas sensor was found to decrease with increasing sensor temperature, and it decreased with increasing NO gas concentration at room temperature. In this paper, it is suggested that CNT gas sensors have a great possibility to be applied as innovative NO gas sensors on the basis of the experimental results.