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Journal of Nanomaterials
Volume 2011, Article ID 707303, 5 pages
Research Article

Humidity Sensor Based on Multi-Walled Carbon Nanotube Thin Films

1Department of Applied Physics, Chongqing University, Chongqing 400044, China
2Department of physics, Chongqing Communication College, Chongqing 400035, China

Received 26 April 2010; Accepted 1 September 2010

Academic Editor: Teng Li

Copyright © 2011 C. L. Cao et al. 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 properties of the humidity sensors made of chemically treated and untreated multi-walled carbon nanotube (MWCNT) thin films are investigated systematically. It shows that both the chemically treated and untreated MWCNT thin films demonstrate humidity sensitive properties, but the former have stronger sensitivity than the latter. In the range of 11%–98% relative humidity (RH), the resistances of the chemically treated and untreated MWCNT humidity sensors increase 120% and 28%, respectively. Moreover, the treated humidity sensors showed higher sensitivity and better stability. In addition, the response and recover properties, and stabilization of the humidity sensors are measured, and the humidity sensitive mechanisms of the sensors are analyzed. The humidity sensitivity of carbon nanotube thin films indicates it promise as a kind of humidity sensitive material.