A simple approach in fabricating chemical sensor using laterally grown multi-walled carbon nanotubes

In this work, we proposed a new process for fabricating chemical sensors employing multi-walled carbon nanotubes (MWNTs) as the active sensing element. The MWNTs were selectively grown between lateral sides of the catalytic metals on pre-defined Nb electrodes. Upon exposure to air or NH3, the electrical resistance of the MWNTs is found to decrease or increase, respectively. The response time decreases and the sensitivity increases while measurement temperature and gas concentration increase. Though there are a few technical problems to be solved, our results show a promising technique for chemical gas sensor. (C) 2003 Elsevier B.V. All rights reserved.