Investigation into the optoelectrical properties of TiO2thin films, deposited by RF magnetron sputtering using powder target

Abstract

TiO2 thin films were deposited at different deposition times and argon flows, onto glass substrates by radio-frequency (RF) magnetron sputtering technique, using a powder target. The X-ray diffraction analysis shows that the increase in the deposition time introduces an improvement in crystallinity of the deposited films with the formation of a rutile phase. This rutile phase is maintained for the samples elaborated at different argon flows. The optical transmittance for all the samples is found to be higher than 75% in the visible region. A slight decrease of the band gap values is observed for all the studied films. The electrical conductivity and conduction mechanism are also studied by means of the impedance spectroscopy technique. The activation energy values calculated from angular frequency and DC conductivity are in good agreement, indicating that the conduction mechanism is thermally activated by hopping between localized states. Additionally, the investigation of the frequency and temperature dependence of AC conductivity agrees with the correlated barrier hopping model.