The structural, optical, topographical, and H2 sensing characteristics of a Zn-doped Fe2O3 thin layer deposited via DC & RF magnetron co-sputtering method

Abstract

In this study, a Zn-doped iron oxide layer was deposited onto a microscope slide using the magnetron co-sputtering technique with direct current (DC) and radio frequency (RF) sources. We comprehensively characterized the resulting Zn-doped Fe₂O₃ thin layer, employing techniques such as XRD, Raman spectroscopy, UV–VIS spectrophotometry, SEM, EDX, & AFM. XRD examination showed the nanocrystalline structure in the thin layer under investigation. Based on recorded absorption data, the band gap energy value calculation resulted in a value of 2.23 eV for the thin film. Raman spectroscopy identified peaks possessing Raman shifts from 100 to 1400 cm⁻¹. SEM investigation illustrated a consistently uniform thin film surface characteristic throughout the substrate. Additionally, the AFM study disclosed a small RMS roughness value, indicative of an unrough surface for the Zn: Fe₂O₃ thin layer. The Fe₂O₃ thin film doped with Zn employing a 30 W DC voltage demonstrated effective hydrogen sensing capability at 300 °C, achieving notable response and recovery time. This work presents a novel application of Zn-doped Fe₂O₃ thin films as highly sensitive and stable hydrogen sensors, tailored for high-temperature environments. The unique combination of nanocrystalline structure and Zn doping optimizes the material’s electronic properties, enhancing its responsiveness to hydrogen gas. This approach offers a scalable, cost-effective pathway for developing advanced sensor technologies suited to environmental monitoring, industrial safety, and hazardous gas detection, making it a valuable addition to the field of gas-sensing materials.