Effect of temperature on gas sensing properties of lithium (Li) substituted (NiFe2O4) nickel ferrite thin film

In particular, less attention has been paid to lithium substituted nickel ferrite thin films for gas sensing studies. In this work, lithium substituted nickel ferrite thin film was prepared by chemical co-precipitation method. The Rietveld refinement X-ray diffraction (XRD) analysis provides all reflection planes of lithium substituted nickel ferrite thin film and reveals well formation. Scanning electron microscopy (SEM) reports the surface of thin film has needle structure particles and X-ray photoelectron spectroscopy (XPS) depicts the presence of all necessary elements. Brunauer-Emmett-Teller (BET) analysis provides adsorption and desorption rate of sensor film. UV-Vis absorption spectroscopy shows that the film has absorption peak which is in visible region. Transmission electron microscopy (TEM) presents rod structure nanoparticles with huge space and confirms the formation of lithium substituted nickel ferrite thin film from selected area electron diffraction (SAED) pattern. Hydrogen gas sensing tests shows that the optimal sensing temperature was 200 °C and sensor produces 95% reproducibility.