Preparation and characterization of nanocrystalline nickel ferrite thin films for development of a gas sensor at room temperature

In the present work, synthesis and characterization of thin films of nanostructured nickel ferrite (NiFe2O4), and its employment as liquefied petroleum gas (LPG) and carbon dioxide gas (CO2) sensors operable at room temperature (27 A degrees C), have been reported. These thin films have been prepared using sol-gel spin coating technique. The structural and surface morphological properties of the fabricated films were studied by X-ray diffraction (XRD) and scanning electron microscopy, respectively. Single phase formation of inverse spinel structure (NiFe2O4) was confirmed by XRD data. The synthesized NiFe2O4 exhibits crystallite size similar to 23 nm, porosity similar to 38 % and specific surface area similar to 57 m(2) g(-1). In order to check the potential applicability of the fabricated films as gas sensor, the modulations in electrical behavior of the film had been recorded by exposure of LPG and CO2 respectively, in a controlled gas chamber. The mechanism of gas sensing of NiFe2O4 thin film has been explained on the basis of surface adsorbed oxygen on the surface of a sensor. The sensing results show that the fabricated sensor is challenging for the leakage detection of LPG as it possesses high sensitivity, stable behavior in long run and small response and recovery times towards LPG.