Single-walled carbon nanotube (CNT) gas sensors were fabricated by dielectrophoresis onto microelectrodes made of Cr, Pd or Al. The Al/CNT sensor response to NO 2 (nitrogen dioxide) gas was characterized by fast and large resistance increase at the moment of NO 2 exposure, whereas the resistance of the other metal/CNT sensors monotonously decreased. It was suggested that the adsorbed NO 2 molecules might alter the Schottky barrier at the Al/CNT interface as well as the positive hole density in the p-type semiconducting CNT. The Al/CNT sensor response could be interpreted as a superposition of the Schottky contact resistance and the CNT resistance, which were differently influenced by the NO 2 adsorption and contributed to the overall sensor response. The Schottky response of the Al/CNT sensor was approximately one order of magnitude faster than the CNT response obtained using the other metal electrodes.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Electrical and Electronic Engineering
- Materials Chemistry