Optical, Electrical and Structural Investigation on Different Molarities of Titanium Dioxide (TiO2) via Sol-Gel Method

Abstract

Titanium dioxide (TiO₂) solution having different molarities were synthesized and deposited on glass substrates by using sol-gel spin-coating method. The variation in thickness, optical, electrical and structural properties of TiO₂ thin films were investigated by surface profiler (SP), UV-Vis spectroscopy, two-point probes and atomic force microscopy (AFM), respectively. The result show that the thickness of TiO₂ thin film increases as the molarities increases. The optical band gap energy decreases from 3.78 eV to 3.07 eV as the TiO₂ molarities increases from 0.01M to 0.20M. The maximum value of the absorption coefficient was 16.27 x 10⁴ cm^-1 at 0.20M with surface roughness of 21.45 nm. Thin films deposited with 0.01M show lower absorption coefficient (3.87 x 10⁴ cm^-1) within visible region with surface roughness of 5.21 nm. The improvement in optical and structural properties of TiO₂ thin films affects the electrical properties as the highest conductivity 9.62 x 10² S/m is obtained by 0.20M.