Preparation of nano-In2O3 thin films by spray pyrolysis for gas sensing application

We report preparation of nano-In2O3 thin films by a simple, inexpensive spray pyrolysis (SP) method and their gas sensing application. Nano-In2O3 thin films were prepared by using indium trichloride in de-ionised water as a precursor at substrate temperature 350°C. As-prepared In2O3 thin films were used for further characterisation after annealing at temperature 550°C for 30 min. The structural and surface morphological properties of the films were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. These films were tested to various gases at different operating temperature ranging from 50°C to 450°C. A high value of sensitivity is obtained for ethanol at operating temperature of 350°C for 80 ppm. The mechanism of ethanol sensing by the In2O3 thin film is explained on the basis of adsorbed oxygen on the sensor surface. The In2O3 thin films exhibited good sensitivity and rapid response-recovery characteristics to ethanol.