Investigation of optical, structural, and electrical properties of heterostructure Fe2O3 deposited by RF magnetron sputtering on ZnO layer by spray pyrolysis

Abstract

In this study, firstly, ZnO thin film was produced on glass substrate by chemical spray pyrolysis method at 450 °C and then Fe2O3 layer was produced on ZnO substrate thin film by RF magnetron sputtering technique. Fe2O3/ZnO heterostructure was fabricated. The crystal structure, surface morphology and structure, chemical composition, optical and electronic properties, and electric properties of the ZnO and Fe2O3/ZnO samples were performed by X-ray diffraction (XRD), Raman spectrometer, field emission scanning electron microscope (SEM), focused ion beam (FIB) microscope, atomic force microscope (AFM), energy-dispersive X-ray (EDX), ultraviolet–visible spectrophotometer (UV–VIS), and Hall measurements, respectively. XRD and Raman measurements showed that ZnO and Fe2O3 thin films have wurtzite hexagonal and cubic crystal structures, respectively, and both are in polycrystalline form. FE-SEM and cross-sectional FIB-SEM images indicate that Fe2O3 flake-like nano-sized structures are formed on the ZnO substrate. In addition, AFM images revealed that the Fe2O3 nano-sized structure was distributed as nanosheets on the ZnO thin-film surface. UV–VIS measurements of ZnO revealed that the ZnO and Fe2O3/ZnO heterostructure band gap energies were 3.277 eV and 3.24 eV, respectively. Finally, the calculated values of electric conductivity, σ, electron density, n, and electron mobility, μ, using the data obtained from Hall measurements are 4.39 × 102 Ω−1 m−1, 6.88 × 1021 m−3, and 3.99 × 10–1 V−1m2s, respectively.