Low temperature study of nanostructured Fe2O3 thin films as NO2 sensor

Nitrogen Dioxide (NO2) is a reddish-brown toxic gas with a characteristic sharp, biting odor and is a prominent air pollutant. However, not as much of the NO2 gas sensors based on Fe2O3, low sensitivity and high temperatures. The iron oxide (alpha-Fe2O3) films were prepared by spin coating method on corning glass substrate over Pt inter digital electrodes (IDEs) and characterized for structural and morphological properties by means of X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM), which proved the strong interaction among Fe2O3 nanoparticles. It was found that alpha-Fe2O3 thin film operating at room temperature could detect NO2 at low concentration (20 ppm) with very high selectivity and sensitivity, with better stability. The sensing mechanism of alpha-Fe2O3 materials to NO2 was presumed to be the synergism of alpha-Fe2O3. The prepared nanostructured alpha-Fe2O3 film showed a high sensing response (S = R-g/R-a - 1, R-g: resistance in presence of gas, R-a: resistance in presence of air) of about 1.14x10(2) towards 20 ppm of NO2 gas at a lower operating temperature. Besides giving the higher sensing response towards NO2 gas, alpha-Fe2O3 sensor structure was observed to be highly selective and showed the poor gas sensing response towards other interfering gases including 2000 ppm of Acetone, IPA, NH3, LPG and CO2 gases ranged from 0.89 to 1.05. (C) 2015Elsevier Ltd. All rights reserved.