abstract
Titanium dioxide thin films have been deposited by reactive magnetron sputtering on glass and subsequently irradiated by UV radiation using a KrF excimer laser. The influence of the laser fluence (F) on the constitution and microstructure of the deposited films is studied for 0.05 < F < 0.40 J/cm(2). The diffraction data reveal that as deposited films are amorphous, while irradiated films present an anatase structure. Additional Raman spectroscopy study shows better crystal quality for the films irradiated with F < 0.13 J/cm(2). The film morphology appears to be strongly modified after laser treatment. Atomic force microscopy and scanning electron microscopy measurements reveal fractally textured films presenting characteristics of high porosity and high specific surface area. Finally, contact angle analysis suggests hydrophobic or wetting behavior depending on F. In order to explain the laser-induced structuration mechanisms, we have successfully applied a fractal as well as the nucleation theories. We propose that electronics effects could be responsible for the observed crystallization.
keywords
PULSED-LASER DEPOSITION; EXCIMER-LASER; BILAYER FILMS; CRYSTALLIZATION; SURFACES; GLASS; SOL
subject category
Physics
authors
Van Overschelde, O; Guisbiers, G; Hamadi, F; Hemberg, A; Snyders, R; Wautelet, M
Groups
acknowledgements
The authors are grateful to C. Motte and M. Olivier (F.P.M.s) for their help in contact angle experiments and P. Leclere for AFM measurements. Two of us (R.S. and A.H.) acknowledge the Belgian Government through the