2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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Clean Technology 2008

Developing of a MEMS-based ionization gas sensor for hydrogen sulfide detection by carbon nanotubes

B-W Chang, R.L-C Chen, C-H Chen, D.C-H Chen
Hungkuang University, Taiwan, TW

Keywords:
hydrogen sulfide, multi-walled carbon nanotube, lift-off technology

Abstract:
The purpose of this study was to develop an ionization gas sensor for hydrogen sulfide detection by multi-walled carbon nanotube (MWCNT) applied. The miniature gas sensor (5 x 12 mm) was fabricated by lift-off technology and was spin-coated a layer of MWCNT film on microelectrode. We used the feature of electric breakdown of gas in a high electric field to characterize the composition of gas. By scanning voltage applied, the discharge current was induced and the gas molecules were broken to gas ions. Also the discharge current was recorded together as the index to quantify the gas concentration. The result shows that the breaking voltage can down to tens voltage for using MWCNT electrode, and the current was proportional to the number of ion charge. The detection limit, in our case, it approximated to a sub-ppm level. Moreover, we also investigated the behavior of sulfide dioxide in high electric field. Their electric property is similar to the monitoring of hydrogen sulfide and is successfully identified by our system. Finally, this gas sensor based on MWCNT coated, it provide a chance to develop a portable bad-smell sensor in environment monitoring with low voltage operation.


Nanotech 2008 Conference Program Abstract