Crystallization behavior of TiO2 thin films

Thin films of titanium dioxide (TiO2) have attracted considerable attention in the past few years, since nanocrystalline TiO2 shows outstanding properties and has widespread application potential. The possible applications range from solar cells and energy conversion systems, gas and UVsensors, battery systems to photocatalysis and self-cleaning surfaces. All these applications rely on the semiconducting property of the TiO2, which is only found in crystalline TiO2. Crystalline TiO2 has three natural crystalline modifications (named anatase, rutil and brookit), which differ in their semiconducting characteristics [1]. Consequently, usually a defined crystalline state is desired for a particular application. For example, anatase TiO2 has a higher electric conductivity as compared to rutil TiO2 and is therefore preferred in solar cell and electronic applications.