TIO2 ANATASE THIN-FILMS AS GAS SENSORS

The anatase modification of TiO2 shows properties quite different from those of the extensively studied and used rutile phase. We have investigated the chemi-resistive behavior of anatase TiO2 thin films exposed to oxidizing and reducing gases (O-2, H-2 and ethanol) in the temperature range between 300 and 400 degrees C. The undoped anatase films demonstrate significant and rapid response to ethanol as well as an appreciable response to hydrogen. The high electron mobility and the low density of trapping or compensating centers are considered to have contributed to this good response. Doping the anatase thin films with Sr, Ce, Y and Tb makes them insensitive to hydrogen, but still sensitive to ethanol. The modification of the sensitivity and its dynamics by dopants have been measured and analyzed.