Laser densification of TiO2 films prepared by aerosol assisted vapour deposition

This paper concerns the microstructural development and phase transition of the aerosol deposited nanocrystalline titanium dioxide films by laser densification. Dense titanium dioxide films have been prepared using laser densification of porous films, which have been deposited using aerosol assisted spray deposition (AASD) at low temperature from a colloidal suspension and a metalorganic precursor. The AASD process involves spraying atomized aerosol precursor towards a heated zone where the droplets undergo chemical reactions at the heated substrate to deposit a solid film. Processing parameters can be varied to control microstructure, porosity, grain size and phase of the titanium dioxide films. The effect of the processing parameter of laser energy density has been investigated and 7.6-7.8 J mm−2 is an optimal energy density for laser densification of titanium dioxide films prepared by the AASD. X-ray diffraction (XRD) was used to analyze the crystalline phase of titanium dioxide films before and after laser irradiation and heat treatment. The microstructure of laser irradiated films and the morphology of nanoparticle precursor were characterized using scanning electron microscopy (SEM) and transmitting electron microscopy (TEM). Laser densification has been shown to be a promising technique to densify porous films rapidly without deleterious effect on thermally sensitive substrates.