Improving the properties of Fe2O3 by a sparking method under a uniform magnetic field for a high-performance humidity sensor

Iron oxide (Fe2O3) thin films are promising semiconductors for electronic applications because Fe2O3 is an earth-abundant semiconductor with an appropriate band gap. However, many methods for the synthesis of Fe2O3 thin films require a corrosive source, complex procedures, and many types of equipment. Here, we report, for the first time, a simple method for Fe2O3 deposition using sparking under a uniform magnetic field. The morphology of Fe2O3 displayed an agglomeration of particles with a network-like structure. The crystallite size, % Fe content, and optical bandgap of Fe2O3 were influenced by changes in the magnitude of the magnetic field. For application in humidity sensors, Fe2O3 at a magnetic field of 200 mT demonstrated a sensitivity of 99.81%, response time of 0.33 s, and recovery time of 2.57 s. These results can provide references for new research studies.