Characterization of epitaxial TiO2 films prepared by pulsed laser deposition

Epitaxial titanium dioxide thin films with anatase and rutile structures have been deposited by pulsed laser deposition (ArF excimer laser) under a controlled O-2 atmosphere. The anatase TiO2 (0 0 1) films have been successfully prepared on LaAlO3 (0 0 1), LSAT (0 0 1), SrTiO3 (0 0 1) and YSZ (0 0 1) substrates. Also, high-quality epitaxial rutile TiO2 (10 0) films were grown on alpha-Al2O3 (0 0 0 1) substrates. The substrate temperature during the deposition was in the range from 349degreesC to 608degreesC under 6 x 10(-3) Torr O-2 gas pressure. The quality of films and crystallographic relationships were assessed by X-ray diffraction, X-ray pole figures and Rutherford backscattering spectroscopy (RBS)/chalineling. The optical properties were characterized in the ultraviolet-visible region by optical absorption measurement. The optical band gaps for anatase and rutile TiO2 epitaxial films were evaluated to be 3.22 and 3.11 eV, respectively. (C) 2002 Elsevier Science B.V. All rights reserved.