Investigation Study on the Zn Doping Effect on the Structural and Morphological Characteristics of Fe2O3 Thin Films for Future Gas Sensor Applications

Abstract

In this work, thin films of undoped hematite (a-Fe₂O₃) and Fe₂O₃ doped with various concentrations of Zn (2, 4, 6, and 8 at.%) were deposited on a glass substrate using the chemical spray pyrolysis technique. The effect of Zn ions on the structural, topographical, morphological, and chemical properties of hematite was investigated. Structural analysis revealed hematite phase crystallization with a hexagonal crystal structure, with crystallite sizes ranging from 36.7 to 50.2 nm. Topographical analysis showed surface features where atoms aggregated to form hill- and plateau-like structures, free of cracks. Grain sizes ranged from 43 to 80 nanometers. As the concentration of Zn dopant increased, there was an observed increase in both surface roughness and root-mean-square values. Morphological analysis indicated a porous microstructure with surface porosity increasing as Zn concentration rose. The average particle size increased from 86 to 114 nm at a Zn concentration of 8 at.%. Therefore, it can be concluded that the hematite doped with Zn²⁺ exhibits promising characteristics for utilization in gas sensor devices.