Deposition of Titania Thin Films by a Peroxide Route on Different Functionalized Organic Self-Assembled Monolayers

• Published in: Chemistry of materials Vol. 13; no. 5; pp. 1552 - 1559
• Main Authors: Niesen, Thomas P, Bill, Joachim, Aldinger, Fritz
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 21.05.2001
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Self assembly; Atomic force microscopy; RBS; Inorganic compounds; Transition element compounds; Oxides; Sulfonates; Experimental study; Substrates; Ellipsometry; Thin films; Thickness; Titanium oxides; Functionalization; Aqueous solutions; Topography; Monolayers; Crystal growth from solutions; Peroxides; Chemical composition; SEM; Microstructure; TEM; Organic compounds
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm001227w

Self-assembled monolayers (SAMs) on single-crystal Si wafers have been used as substrates for the deposition of oxide thin films. The organic surface has been shown to be effective for promoting the growth of films from aqueous solutions at temperatures below 100 °C. In the present study, the formation of a titanium complex in the presence of H2O2 is used to stabilize an otherwise spontaneously precipitating aqueous titanium solution. Uniform titania films have been formed at 80 °C on sulfonated SAMs, whereas hydroxyl and amine functionalities led to inhomogeneous coatings. The films were characterized by a variety of techniques, including ellipsometry, RBS, AFM, SEM, and TEM, to determine the thickness, topography, microstructure, and chemical composition of the films. An electronegativity−pH diagram is used to explain how the composition of the deposition solution is reflected in the final thin film, both for the present films and for titania films reported earlier in the literature. Finally, the current understanding of the film formation mechanism is discussed.