A simple route to synthesize nanocrystalline TiO2 films at room temperature

At room temperature, TiO2 films were deposited by direct current pulse magnetron sputtering. Varying the O2/Ar flow ratio, TiO2 films with different crystalline structures and surface morphologies were obtained. X-ray diffraction spectra and atomic force microscopy showed TiO2 films mainly existed as amorphous and crystalline structures when the O2/Ar flow ratio was less and more than 6/14, respectively. With these results, a critical point was found at O2/Ar = 6/14. The film growth behavior was controlled by the shadowing effect and the mixture of crystallographic orientation and grain growth effects, when the O2/Ar flow ratio was less and more than the critical point, respectively. The present work reveals a simple way to prepare the high quality anatase phase TiO2 films at room temperature, as well as the growth mechanism behind it.