Study on TiO2 thin films grown by advanced pulsed laser deposition on ITO

TiO2 films were grown by an advanced pulsed laser deposition method (PLD) on ITO substrates to be used as functional electrodes in the manufacturing of solar cells. A pure titanium target (99.99%) was irradiated by a Nd:YAG laser (355 and 532 nm, 5 ns, 35 mJ, 3 J/cm2) in an oxygen atmosphere at different pressures (20–160 mTorr) and at room temperature. After deposition, the films were subjected to an annealing process at 350 °C. The film structure, surface morphology, thickness, roughness, and optical transmission were investigated. Regardless of the wavelength used, the films deposited at room temperature presented only Ti2O and TiO peaks. After thermal treatment, the TiO2 films became strongly crystalline, with a tetragonal structure and in the anatase phase; the threshold temperature value was 250 °C. The deposition rate was in the range of 0.035–0.250 nm/pulse, and the roughness was 135–305 nm. Optical transmission of the films in the visible range was between 40% and 60%.