Miniature gas sensor for hydrogen sulfide
B.W. Chang, R.L.C. Chen, D.C.H. Chen
Hungkuang University, Taiwan, TW
Keywords: carbon nanotube, hydrogen sulfide, gas ionized
Abstract:In this study, we successfully developed a miniature gas sensor for hydrogen sulfide detection by using a screen-printed carbon nanotube (CNT) electrode. This miniature gas sensor (5 x 12 mm) was fabricated by lift-off technology and was spin-coated by a layer of MWCNT film on microelectrode. Based on the principal of gas ionized, the gas molecules in a high DC electric field will be broken into an ionized molecule and induce the discharge current simultaneously. We can effectively identify the gas type and concentration by measuring this breaking voltage and discharge current. The result shows that the characterized sensing voltage for hydrogen sulfide detection can be recognized in our developed system, it appeared around a one hundred voltages. The discharge current was proportional to the level of hydrogen sulfide. For the detection limit in our case, we can detect the gas approximated to a ppm level. Moreover, we also investigated the discharge behavior of sulfide dioxide. Their electric property was similar to the measuring of hydrogen sulfide and was successfully identified by our system. Finally, this gas sensor based on CNT coated, it provide a chance to develop a portable bad-smell sensor for environment monitoring in a low voltage operation.