Ozone sensing properties of In2O3-based semiconductor thick films

Ozone sensing properties of In2O3-based semiconductor thick films have been investigated. The In2O3 sensing layer is quite sensitive to ozone, but the rapid saturation in sensitivity cannot be obtained. The addition of Fe2O3 (3 wt.%) into In2O3 and the high temperature firing of the mixed powder give rise to a remarkable improvement in response and recovery, although the sensitivity decreases. The sensing layer fired at 1300°C and operated at 550°C shows excellent properties such as fast response, stable sensitivity, and rapid recovery. In addition to it, the sensor shows a good linearity with ozone concentration and a good reproducibility. The preliminary results clearly demonstrated that the sensor was successfully applied for the ozone detection of parts per billion range.