Effect of Annealling on Optical Band Gap of Fe2O3 Thin Films on Amorphos Transparent Glass Substrate by Spray Pyrolysis Method

M. K. Rahangale; Lalitkumar M. Shanware

Abstract

The Fe 2 O 3 thin film has widely used photo-electrochemical cells. In this paper, the optical properties like band gap of thin films is depend on annealed temperature at 100 o C and 200 o C was discussed. The optical property of Fe 2 O 3 are studied by UV- Vis spectroscopy .The optical band gap decreased after increasing annealing temperature. The refractive index of Fe 2 O 3 was found in between 2.05eV to 2.25eV.After annealing it indicates an better effect on crystallinity. The preparative parameters have been optimized to obtain good quality thin films which are uniform and well adherent to the substrate. The deposited iron oxide thin films show the single hematite phase with polycrystalline rhombohedral crystal structure with crystallite size 20–40 nm. Optical analysis enabled to point out the increase in direct band-gap energy from 2.2 to 2.25 eV with doping concentration which is attributed to a blue shift. The XRD pattern showed that the Fe 2 O 3 films exhibit amorphous in nature. Formation of iron oxide compound was confirmed from FTIR studies. The optical absorption showed existence of direct optical band gap of energy 2.2 eV. Fe 2 O 3 film surface showed superhydrophilic nature with water contact angle less than 10°. The Fe2O3 thin film has potential applications in gas sensors, magnetic resonance imaging, photo-electro chemical cells. This thin film has high refractive index, wide band gap and chemical stability make them suitable for use as gas-sensors In this the effect of annealing temperature on specific properties of this thin film were studied