MoO3:In2O3binary oxide thin films as CO gas sensor

The aim of the study was to understand gas sensing properties of thin films of molybdenum trioxide and indium oxide (MoO3-In2O3) indifferent normality proportions. Thin films were prepared by spray pyrolysis technique on glass substrates at 400°C. The films were characterised using X-ray diffraction, scanning electron microscope and energy dispersive analysis by X-ray spectra. The electrical and gas sensing properties of the films were studied using static gas sensing apparatus. The resistivity of films increased by adding MoO3as the dopant in In2O3. The maximum resistivity of film was found 1.75 × 104Ωm for 0.3N (MoO3) and 0.1N (In2O3) binary oxide films. The films were tested against five different target gases. The composition ratio 0.3N:0.1N films showed the 70.50% sensitivity for 300 ppm CO gas at 150°C. The response time (15s) and recovery time (25s) was found to be quick.