Optical and electrical properties of sol-gel spin coated titanium dioxide thin films

In this work; TiO₂ thin films were deposited on glass and stainless steel substrates by sol-gel spin coating method. The films deposited on glass were annealed at different temperatures (T_a) in the range of 200 to 500 ⁰C and that are deposited on steel substrate were annealed at 800 ⁰C. The optical properties of TiO₂ thin films were studied by using UV-VIS spectroscopy and photoluminescence (PL) spectroscopy. The transmittance on the average was found to ≥ 80 % and is found to sensitive to T_a. The PL spectra exhibited the strong emission band associated with band- to- band transition around 390 nm and the two weak bands at 480 and 510 nm associated to the oxygen defects and surface defects respectively. The current-voltage (I-V) characteristics of the Al/TiO₂/steel capacitors were studied and analysed with application of various current mechanisms. Analysis reveals that the conduction in Al/TiO₂/steel capacitors is governed by Poole-Frenkel mechanism. (paper)