Effect of gamma-irradiation on optical, structural and electrical properties of In2O3: F thin films for photocatalysis application

Abstract

Fluorine-doped indium oxide thin films (In2O3: F) have been successfully synthesized by spray pyrolysis technique on glass substrates and irradiated by different doses (1, 5, 10 and 100 kGy) of gamma-radiations using Co60 gamma source. The effect of this high energy on physical properties of In2O3: F has been studied by X-Ray diffraction, Raman spectroscopy, Spectrophotometer, Photoluminescence spectrometer and Hall Effect measurements. In our study γ-radiation induces an enhancement on the physical properties of fluorine doped indium oxide thin films. Especially at 10 kGy, optical transmission and electrical resistivity were improved after irradiation so the transparent conductor character has been improved also. In2O3: F thin film crystallized into the cubic structure with predominant plan orientation (4 0 0) located at 2θ = 35.46°. An increase of transmission values from 77 to 83% is detected after irradiation. The optical band gap increases from 3.01 eV to 3.18 eV. The effect of gamma radiation on optical constants such as refractive index n (λ), extinction coefficient k (λ), lattice dielectric constant εL, high frequency dielectric constant ε∞, plasma frequency ωP have been determined. The Wemple model based on the envelope method were applied to calculate the single oscillator energy E0 and dispersion energy Ed. A decrease of electrical resistivity from 0.43 to 0.14 Ω cm is also detected after irradiation. All these experimental results suggest that In2O3: F thin films can be used as transparent conductive electrode in photovoltaic devices. This study also illustrates that In2O3: F thin film irradiated at 100 kGy can be used as a photocatalytic material with an efficiency to decompose the dye around 84%.