Uv Laser Irradiation-induced Crystallization In Titania Thick Films Prepared Using A Sol-gel Method

Titanium dioxide films of 5 µm thickness have been deposited on soda-lime glass substrates by dip-coating from a suspension of titanium dioxide powder prepared using a sol-gel route. After a heat-treatment, the obtained films have been irradiated using ArF excimer laser. The effect of the laser fluence, ranging between 115 mJ/cm2 and 495 mJ/cm2; on the crystallization of the deposited films has been studied. The irradiated areas were characterized using micro-Raman spectroscopy. While the as-deposited films were amorphous, irradiated areas display anatase or rutile crystalline structures, depending on the laser fluence. The corresponding local temperature range was evaluated to 700-800°C. Moreover, the apparent darkening of the layer when increasing the laser fluence was attributed to a re-arrangement of particles under laser-annealing.