Structural and morphological properties of TiO$_{2}$thin films prepared by spray pyrolysis

Abstract

In the present work the ultrasonic spray pyrolysis technique was employed to produce TiO$_{2}$ thin films on fused quartz and on silicon substrates. An aerosol, generated ultrasonically, of titanium diisopropoxide was employed in the deposition experiments. The crystallization process of the as deposited samples was studied by X-Ray Difraction (XRD), Raman spectroscopy (RS), Atomic Force Microscopy (AFM), and optical transmission spectroscopies (TS). The results show that spray pyrolysis technique is able to produce films with smooth surface and good crystalline properties. When deposition temperatures were below 400$^\circ$C, the films grow with a flat surface (roughness $ \sim $5{\AA}) but in amorphous phase; while for equal or higher values to this temperature, the films develop a crystalline phase corresponding to the TiO$_{2}$ anatase phase, but the surface roughness is increased up to $ \sim $225{\AA}. After annealing at 750$^\circ$C, the samples deposited on Si show a partial transition to rutile phase preferentially oriented in (111) direction; while, under a similar annealing, those films deposited on fused quartz do not show any phase transition.