Preparation of epitaxial TiO2 films by pulsed laser deposition technique

TiO2 films with anatase and rutile structure were deposited by pulsed laser deposition (PLD) with a Nd/YAG laser under the controlled O-2 atmosphere. Epitaxial anatase films have been successfully prepared oil several kinds of oxide substrates with different lattice parameters. Further the high quality epitaxial rutile films were also grown on alpha -Al2O3 (0001) substrate. During the deposition. the substrates were kept at 500 degreesC and exposed to 35 mtorr O-2 gas pressure. The typical thicknesses of epitaxial films ere in the range from 200 to 880 nm. The epitaxial films were analyzed by Rutherford backscattering spectrometry (RBS) combined with channeling and X-ray diffraction for the crystallographic relationships with the substrates. The optical properties cre characterized in the ultraviolet-visible region employing optical absorption and photoconductivity measurements. The optical band gap energies of anatase and rutile TiO2 epitaxial films were evaluated to the 3.22 and 3.03 eV, respectively. (C) 2001 Elsevier Science B.V. All rights reserved.