Mg-doped TiO2 thin films deposited by low cost technique for CO gas monitoring

This research work reports the preparation of Mg-doped TiO2 thin films by the sol–gel spin coating technique. The films deposited on silicon substrate were then used for detection of carbon monoxide (CO) gas at room temperature. The doping of magnesium was varied from 1% to 7% weight/volume. The films were characterized by X-ray diffraction, Ultra–visible spectroscopy and scanning electron microscopy technique. The predominant anatase phase was observed by XRD patterns of Mg-doped TiO2 films. The indirect bandgap calculated by Tauc equation was found to be decrease with increase of Mg dopant into TiO2. The resistivity of doped TiO2 films was also observed to be decrease with increase of doping concentration of magnesium. The response for CO gas was measured by measuring the electrical resistance of the doped films in the concentration range of 120–920 ppm. The TiO2 film doped with 7% wt/v of Mg has high sensitivity, response and recovery time.