Conductometric sensors, based on pure and Au-doped TiO, 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 degrees C and 320 degrees C. Thin films of TiO, 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 TiO, sensor has fast response and recovery time of 10 and 29 s respectively towards 510 ppb of NO, at 273 degrees C. (c) 2007 Elsevier B.V. All rights reserved.