Nanocrystallisation of anatase or rutile TiO2 by laser treatment

We present an original way to produce anatase titanium dioxide (TiO2) nanoparticles from amorphous nanofilm. TiO2 nanofilm has been deposited by reactive magnetron sputtering on glass and subsequently irradiated by ultraviolet (UV) radiation using a krypton-fluor (KrF) excimer laser. X-ray diffraction and transmission electron microscopy reveal that the film has been nanostructured. Experimental results are compared with theoretical predictions concerning the structural phase stability with the size of nanostructures. The size distribution of spherical nanoparticles confirms that the most stable phase is anatase for particle sizes smaller than 40 nm and rutile for sizes bigger than 40 nm.