Preparation and characterization of Fe3O4 nanoparticles for nitrogen dioxide sensing

This work fabricated a NO2 gas sensor by depositing Fe3O4 on a quartz substrate using a pulsed laser deposition method with energies of (700 and 900) mJ. The XRD of the target pellet was examined, and it was found that the target was highly crystalline, with high purity, and no indication of other materials. The thin films prepared with energies of 700 mJ and 900 mJ were studied and analyzed through morphological examinations. When the energy was increased, the AFM indicated an increase in the size of the grains and a decrease in the roughness of the sample 900 mJ, SEM, and EDX to the disappearance of the cubic bodies covering the surface from their melting and fusion and an increase in the Fe element on O element deficiency. The I-V measurements of the samples indicated that the current increased when the gas entered them, and the sample prepared with the energy of 700 mJ was more affected than others. The sensitivity of thin films with 50 ppm NO2 gas was examined with different values of temperature. Samples prepared with 700 mJ and 250 capacities exhibited the best sensitivity with a value of 564.3%. The same sample was exposed to different concentrations (5, 10, 15, 20, 25, 30) ppm and examined at temperature 250. For such case, the sensitivity was (76.1%, 97.3%, 170.3%, 204.4%, 285.4%, 304.9%), respectively.