Sol gel spin coated TiO2 films for transparent window applications

TiO2 films of different thickness were deposited using Sol-Gel spin coating technique using titanium isopropoxide [Ti(OC3H7)(4)] as a precursor. The films were characterized using X-ray diffraction, scanning electron microscopy (SEM) and UV-Vis spectroscopy. The XRD spectra indicate the presence of brookite TiO2 phase in the films. The grain size as calculated using the Scherrer's formula was found to be 28.7, 37.8 and 47.9 nm for TiO2 (121) film of thickness 100, 200 and 300 nm respectively. The grain size increases with increase in thickness of the films. The SEM micrographs show uniformly distributed grains which appear to grow with the thickness. The optical band gap of the TiO2 films of different thickness show a change from 3.55eV to 3.35 eV. The extinction coefficient of the films appears to lie in the range 0.021-0.29.