Structural characterization of TiO2 thin ®lms prepared by pulsed laser deposition on GaAs(1 0 0) substrates

TiO2 thin ®lms on GaAs(1 0 0) substrates were prepared at temperature ranging 30±7508C and pressure from 5 10ÿ4 Pa base vacuum to 15 Pa O2, by pulsed laser deposition (PLD). The effects of both the oxygen pressure and the substrate temperature on the properties of TiO2 ®lms were investigated. TiO2 thin ®lms were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). Optimum parameters have been identi®ed for the growth of high-quality TiO2 ®lms. At 5 Pa of oxygen ambient pressure, rutile TiO2 ®lms with high [1 1 0] orientation were formed at substrate temperature of 7008C. At room temperature (308C) and 5 10ÿ4 Pa base vacuum, rutile TiO2 ®lms with a preferred [1 1 0] orientation were also obtained on GaAs(1 0 0) substrates by PLD. Surface morphology of the ®lms showed marked dependence on the substrate temperature. The grain size and their surface roughness increased with raising substrate temperature.#2001 Elsevier Science B.V. All rights reserved.