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

Synthesis of iron oxide (Fe 2 O 3 ) 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 X-ray diffraction (XRD), revealed that they were γ-Fe 2 O 3 . 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 e tc –, 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.