Structural Changes in Sol-Gel Derived SiO2 and TiO2 Films by Exposure to Water Vapor

Hiroaki Imai, Hirotoki Morimoto, Atsushi Tominaga, Hiroshi Hirashima

Research output: Contribution to journalArticle

106 Citations (Scopus)

Abstract

Structural changes in sol-gel derived thin films by exposure to water vapor were investigated using Fourier transform infrared absorption spectroscopy, ellipsometry and x-ray diffraction. We found that SiO2 gel films were densified with a decrease in OH groups by the exposure at 60°-180° C. The shrinkage and the peak frequency of ω4(TO) for the exposed films were comparable to those heated in a dry atmosphere at temperatures above 500°C. However, OH groups in the films were not completely removed by the water exposure. A subsequent annealing above 300°C changed the structure of the water-exposed SiO2 films with condensation of the remaining OH groups. Although the exposed SiO2 gel films were amorphous, TiO2 gel films were transformed to anatase with a decrease in OH groups by the treatments at 80°-180°C.

Original languageEnglish
Pages (from-to)45-54
Number of pages10
JournalJournal of Sol-Gel Science and Technology
Volume10
Issue number1
DOIs
Publication statusPublished - 1997 Jan 1

Keywords

  • Crystallization
  • Densification
  • Silica
  • Sol-gel films
  • Titania
  • Water vapor

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Chemistry(all)
  • Biomaterials
  • Condensed Matter Physics
  • Materials Chemistry

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