Optical and Electrical Properties Dependence on Thickness of Screen-Printed TiO₂ Thin Films

Abstract

Effect of film thickness on the optical and electrical properties of TiO₂ thin films were studied. Thin films of different thicknesses were deposited by screen printing method on fluorine doped tin oxide coated on glass substrate. The film thickness was determined by surface profile measurement. The thicknesses were 3.2, 8.2, 13.5 and 18.9 μm. Transmittance, reflectance and absorbance spectra were studied using UV-VIS-NIR spectrophotometer in the photon wavelength range of 300-1500 nm for transmittance and reflectance and 350-1200 nm for absorbance. Band gap and refractive index of the films were determined using these spectra. It was found that reflectance, absorbance, band gap and refractive index increased with film thickness while transmittance decreased with increase in thickness. I-V characteristics of the films were also measured by a 4- point probe. Electrical resistivity (𝜌𝜌) and conductivity (σ) where calculated from the I-V values. Resistivity was found to increase with thickness while conductivity decreased with increase in film thickness.