Growth and characterization of sol–gel processed rectangular shaped nanostructured ferric oxide thin film followed by humidity and gas sensing

In the present work nanostructured ferric oxide has been synthesized using sol–gel method. Thin films of ferric oxide were fabricated via spin coating process. The surface of the thin film was scanned by scanning electron microscope that exhibited the surface morphology of ferric oxide nanostructures. The material was also characterized by XRD, Acoustic particle sizer and FTIR. All the particles distributed on the surface have some spaces among them known as pores. These pores serve as adsorption sites for moisture and other gases. EDX confirmed the elements forming the ferric oxide in pure form. The particle size of the ferric oxide was estimated as ~12.2 nm. The pore size of the film was ~50 nm i.e., nature is mesoporous. Annealing effect on the surface morphology was also observed. Humidity sensing, electrical as well as optical of the prepared film was carried out. The results showed the suitability of material for the development of humidity sensors. Variations in resistance with the exposure of LPG were recorded and found that resistance of film increases with the increasing exposure time and concentration of gas. The maximum sensing response of the sensor was recorded as 3.26 for 1000 ppm at room temperature. The response and recovery times of the sensor were found to be ~12 and 9 min, respectively.