PREPARATION AND CHARACTERIZATION OF THIN TIO2-FILMS ON GOLD MICA/

Flat and highly (111) oriented gold and silver films were prepared by physical vapour deposition (PVD) using optimized deposition parameters . On these films, which were characterized with atomic force microscop y (AFM), scanning tunneling microscopy (STM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). titanium dioxide films wer e deposited by electron beam evaporation and dip coating. Dip coating fi om titanium tetraisopropoxide solutions resulted in films with diff erent morphology and coverage depending on the alkoxide concentration (0.009 mol/L - 0.60 mol/L) and the post-treatment. Scanning electron m icroscopy (SEM) and AFM revealed that the deposited TiO2 consists of a morphous. highly porous islands when the applied alkoxide concentratio n is high (0.05 mol/L - 0.6 mol/L). At higher temperatures these amorp hous TiO2 islands sintered significantly and crystallized to anatase. In contrast, transparent TiO2 films were obtained from low concentrate d alkoxide solutions (< 0.01 mol/L) which covered the whole substrate, similar to electron beam evaporated thin films. Sputter profiles with ion scattering spectroscopy (ISS) Indicated that the film thickness i s in the range of 2 nm when alkoxide solutions with a concentration of 9 mmol/L are used. The deposition of TiO2 by electron beam evaporatio n normally resulted in significantly reduced TiO2 films, completely ox idized ones were obtained when deposition was performed at elevated ox ygen partial pressures (p(O-2) > 2 x 10(-5) mbar).