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Journal of Nanomaterials
Volume 2008, Article ID 352854, 4 pages
Research Article

Conductivity-Type Sensor Based on CNT- Composite for NO2 Detection

Department of Applied Chemistry, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan

Received 27 June 2007; Accepted 14 March 2008

Academic Editor: Y. Wang

Copyright © 2008 Takeshi Hashishin and Jun Tamaki. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The CNTs with 20–50 nm in diameter were directly grown on Au microgap electrode by means of thermal CVD at C for 60 minutes under EtOH-Ar- atmosphere (6 kPa). The CNTs with entangled shape formed the network structure with contacting each other. In the CNTs- composite, grains with disk shape (50–200 nm) were independently trapped. The CNTs- composite sensor showed the fairly good sensor response (Ra/Rg = 3.8 at C). The sensor response was greatly improved with CNTs- composite, comparing with that of CNT sensor (Ra/Rg = 1.05). This phenomenon can be explained by formation of p-n junction, between CNT(p) and (n), and thus improvement of adsorption. The sensor response was decreased with increasing the amount in CNTs- composite, suggesting the electronic conduction due to connection.