A high-sensitivity hydrogen gas sensor based on carbon nanotubes fabricated on SiO2 substrate.

In this study, an inexpensive simple method for the fabrication of efficient hydrogen (H₂) gas sensor based on carbon nanotubes (CNTs) was presented. The CNTs were synthesized using microwave oven and deposited onto SiO₂ substrate by a dielectrophoretic method. The as-grown CNTs showed an n-type behavior because CNTs possess the characters of both metallic and semiconductor when placed between the two electrodes, meanwhile, the current was directed mostly by metallic tubes. Upon exposure to H₂ gas at room temperature, the CNTs exhibited high sensitivity up to 315% at 140 ppm H₂, and relatively good sensitivity of 40% at a very low H₂ gas concentration of 20 ppm. To the best of our knowledge, this is the first work involving the fabrication of CNTs for detecting a low H₂ gas concentration of 20 ppm at RT with high sensitivity comparing with other previous studies. [ABSTRACT FROM AUTHOR]