SnO2 nanowires bridged across trenched electrodes and their gas-sensing characteristics

By using a thermal chemical vapor deposition and Au-catalyzed in situ alignment and growth process, SnO2 nanowires could be bridged across trenched electrodes. In this process, a complicated and individual alignment process could be avoided and a number of devices can be fabricated in one step in a wafer scale. The gas-sensing characteristics of the developed sensor were significantly better when compared to those of other types of NO2 sensors reported in the literature. When the concentration of NO2 was 5 ppm, the sensitivity was higher than 150. Especially, the reaction time of 8–14 s was noticeably fast, which is attributed to the microtrench structure beneath the nanowires.