UV effect on indium oxide resistive sensors

Metal oxide semiconductors have been the most intensely investigated materials in gas sensing area for the past several years due to their unique electric properties. Among them, indium oxide (In 2 O 3 ) is an important n-type III-V semiconductor with a band gap of 3.6 eV, which has been widely used for the detection of both oxidizing (e.g., O 3 and NO x ) and reducing (e.g., CO, H 2 S, and H 2 ) gases [ 1 ]. As is well known, the response of gas sensors can be improved by increasing the surface area of the sensing element. Accordingly, gas sensors based on In 2 O 3 nanowires (NWs) and nanotubes (NTs) have been extensively studied because of their improved properties in comparison with the traditional bulk materials, such as the lower operating temperature and better response in the detection of gas concentration at trace levels [ 2 , 3 ]. Being a new, simple, and fl exible technique to synthesize NWs and NTs, electrospinning process has gained increased interest in gas sensing area. Furthermore, to overcome some problems during the functioning at room, low operat-ing temperature, such as the poor sensitivity and long recovery time, the illumination of the sensor with UV radiation is the most studied and promising solution [ 4 ].