Nitrogen dioxide gas sensors based on titanium dioxide thin films deposited on langasite

Conductometric sensors, based on pure and Au-doped TiO2 thin films on langasite (LGS) substrates have been investigated for detecting low concentrations (510 ppb and 1060 ppb) of NO2 in synthetic air at a temperature range between 220 °C and 320 °C. Thin films of TiO2 were deposited using the radio frequency (RF) magnetron sputtering method. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were employed for the characterization of thin films. It was observed that the Au-doped TiO2 sensor has fast response and recovery time of 10 and 29 s respectively towards 510 ppb of NO2 at 273 °C.