TiO2 thin films prepared by PLD for photocatalytic applications

Photocatalytic titanium oxide (TiO2) thin films are synthesized by the Nd:YAG pulsed laser deposition (PLD) technique. The influence of laser repetition rate and substrate temperature on the crystalline structure is investigated by X-ray diffraction (XRD) measurement. Films deposited at a substrate temperature of 150 °C exhibit the anatase form, regardless of the repetition frequency. In films deposited at 300 °C, however, when the repetition rate is increased the crystal form changes from rutile to anatase. The change in crystal form is probably caused by a drop in the surface temperature of the growing film. The effect is very sensitive to repetition rate, which changes the deposition rate. The results suggest that control of the laser-pulse repetition rate in PLD is a very important factor for obtaining highly efficient photocatalytic TiO2 thin films.