Some Structural and Optical Properties of sprayed Iron Oxide Thin films

In this paper α-Fe2O3, thin films were prepared by spray pyrolysis technique via spraying FeCl3·6H2O (10 -2 M) based aqueous solution with a spray flow of 8 ml/min onto heated glass substrates at 350 °C. After deposition, rust red and amorphous films was obtained. After a heat treatment at 400 ° C for six hours, the thin films are well crystallized. In order to study the surface morphology of the films and their crystalline structure, an electron scanning microscope (SEM) and X-ray diffraction were used (XRD). A UV-Vis-NIR spectrophotometer in the wavelength range 200–2500 nm was used to carry out the transmittance and the reflectance of the iron oxide films. The study of the optical properties of the iron oxide thin films was completed by the data acquired using a variable angle spectroscopic ellipsometer in the range 400–1800 nm of wavelength. The results reveal that the sprayed thin films were amorphous and after the heat treatment, the films crystallize in the α-Fe2O3 phase. SEM images show compact and homogeneous films, the estimated optical band gap for allowed direct transition of the iron oxide films was found to be 2.15 eV. On the other hand, the calculated thickness of the films from ellipsometry modeling is about 710 nm.