Structure and optical properties of Zn1−xFexO thin films prepared by ultrasonic spray pyrolysis

Polycrystalline Zn1−xFexO thin films (x ≤ 0.30) were prepared by ultrasonic spray pyrolysis technique onto glass substrates. The XRD spectra show that undoped ZnO film exhibits wurtzite crystal structure. No detectable change in crystal structure is observed for x ≤ 0.10 and poor crystallinity is observed at x = 0.30. Surface morphology of the films obtained by SEM reveals that pure ZnO film has the hexagonal like grain, but the introduction of Fe content in the structure strongly influences the surface morphology of the films. From the optical studies, with increasing x, the band gap energies of the films were found to shift to lower energies than that of pure ZnO. The estimated band gap energies of Zn1−xFexO films represent a linear dependence and are found between 3.45 eV (for x = 0.00) and 3.04 eV (for x = 0.30).