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 (H-2) 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 H-2 gas at room temperature, the CNTs exhibited high sensitivity up to 315% at 140 ppm H-2, and relatively good sensitivity of 40% at a very low H-2 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 H-2 gas concentration of 20 ppm at RT with high sensitivity comparing with other previous studies. [GRAPHICS]