Structural and Optical Characterization of TiO2 Thin Films Prepared by Sol-Gel Process

Abstract

Titanium dioxide (TiO2) thin films were prepared by spin coating technique of sol precursor on Corning 7059 glass substrates. Spectral transmittances of as deposited and annealed samples were measured in the range of 250 to 1100 nm. Optical band gaps were calculated from the Tauc plots and was found to be about 3.78 eV for the annealed samples at 500 degrees C. X-ray diffraction patterns were performed with as deposited and annealed samples. By annealing the samples at 500 degrees C in various annealing times, the structure has changed from amorphous to the anatase crystalline state. Variations of the band gap energy values of TiO2 films with cobalt doping were also investigated. Cobalt doping decreased the band gap value of TiO2 films down to 3.25 eV. X-ray diffraction patterns were also given for the doped samples.