Optical Properties of Non-Crystalline Fluorine Doped Hematite Fe2O3 Thin Films Deposited by Chemical Spray Pyrolysis Technique

Abstract

By using the spray pyrolysis technique, un-doped and Fluorine highly doped iron oxide Fe2O3 thin films were deposited on a glass substrate at a temperature of 380 oC and at different dopant concentrations (10, 15, and 20) %. The crystal structure and optical characterization of the deposited thin film were performed by x-ray diffraction and UV-Vis spectrophotometer. The XRD results revealed that the presence of a very wide peak in-between (15-35) o angles, this gives evidence that un-doped and F-doped Fe2O3 thin films have very low crystallinity and amorphous structures. The optical absorbance edge was shifted towards short wavelengths (blue shift) and the absorbance was reduced with the increase of Fluorine dopant content. The optical constants such as absorption, extinction coefficients, and the optical conductivity of the deposition films were investigated as a function of dopant content. The optical energy band gap of un-doped and Fe2O3:F thin films was found to be increased when increasing of the Fluorine content and exhibited a direct allowed energy gap (Eg) from (2.55 to 2.7) eV which can related to the Burstein-Moss effect.