Effects of temperature on the optical properties of iron oxide (Fe2O3) thin films synthesized by chemical bath deposition

Synthesis of iron oxide (Fe2O3) thin films on glass substrates was carried out by chemical bath deposition technique, with a view to investigate the effects of variation of temperature on the optical properties of the films. Structural characterization of the films obtained by Xray diffraction (XRD), revealed that they were-gamma-Fe2O3. The optical property study revealed that the as deposited films had a transmittance of about 75-90% in the VIS-NIR regions of electromagnetic spectrum, but this was slightly reduced to a range of about 70-83% in the same regions when treated with heat. Their band-gap was found to be 2.38 eV for the unannealed, while it ranged from 2.55-2.68 eV for the annealed films. A variation in other optical properties - refractive index, extinction coefficient etc -, was observed with heat treatment of the films, though not sequential. Their optical properties and band gaps make the films good materials for wide range of applications. (C) 2016 Elsevier GmbH. All rights reserved.