Performance Improvement of NO2; Gas Sensor Using Rod-Patterned Tantalum Pentoxide-Alloyed Indium Oxide Sensing Membranes

The performances of nitrogen dioxide (NO2) gas sensors using various dimensional tantalum pentoxide-alloyed indium oxide (Ta:In2O3) rod arrays were investigated, in which the rod arrays were patterned by a laser interference photolithography system. The rod number amount and the surface area-to-volume ratio increased with a decrease of the period of rod array. The best responsivity of 76.1 and the lower operation temperature of 110 degrees C for the NO2 gas sensors using the sensing membranes of 0.6- $\mu \text{m}$ -periodic Ta:In2O3 rod array were obtained. Besides, the limiting sensing concentration of 0.7 ppm could be detected using the associated NO2 gas sensors. Furthermore, the response time and the recovery time were respectively reduced to 48 s and 329 s, respectively, when the NO2 gas sensors operated at 110 degrees C under NO2 gas concentration of 100 ppm.