Enhanced Humidity Sensing Performance of Fe₂O₃:ZnO/MWCNTs Nanocomposite: Fabrication and Characterization

This work was dedicated to the synthesis and characterization of Fe₂O₃:ZnO/MWCNTs (multiwalled carbon nanotubes) nanocomposite as a high-performance humidity sensor. The Fe₂O₃:ZnO composite was prepared by a simple and inexpensive solid-phase synthesis method by using thermal annealing. The sensor fabrication involved the deposition of the Fe₂O₃:ZnO thin film and MWCNTs onto the sensor substrates using radio frequency (RF) magnetron and e-beam deposition methods, respectively. Various characterization techniques, including scanning electron microscopy, profilometry, energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy, and X-ray photoelectron spectroscopy, were employed to investigate the material properties of the Fe₂O₃:ZnO/MWCNTs nanocomposites. The sensor responses were measured toward a relative humidity range of 2.2%-98%, where their values changed from 1.5 to 5, respectively. The high selectivity and temporal stability of the sensor were confirmed by the experimental results. Besides, the Nyquist curves of the Fe₂O₃:ZnO/MWCNTs material were extracted using the impedance investigation, and an equivalent electrical circuit was proposed. Thus, this work will contribute to the implementation of highly efficient and viable sensors in humidity detection systems.