Tantalum and Titanium doped In2O3 Thin Films by Aerosol-Assisted Chemical Vapor Deposition and their Gas Sensing Properties

In2O3 and In2O3:M (M = Ti or To) thin films were deposited on glass substrates via aerosol- assisted chemical deposition (AACVD) at 450 degrees C. The resulting films were characterized by a range of techniques including glancing-angle X-ray diffraction, scanning electron microscopy, wavelength dispersive analysis of X-rays, and optical transmission/reflectance studies to investigate the effect of doping on the films. The In2O3:M thin films were found to contain 6.5 and 2.3 at.% of Ti and Ta, respectively. The gas sensing properties were investigated on films deposited onto gas sensing substrates via AACVD. Tantalum doped indium oxide (In2O3:Ta) thin films showed a superior response, compared to In2O3, to a number of reducing gases (ethanol, CO, ammonia) and also the oxidizing gas NO2. Considerable selectivity to ethanol was observed; the greatest gas response (R/R-0) was 16.95 to 100 ppm ethanol.