Synthesis and characterization of TiO2 thin films on organic self-assembled monolayers: Part II. Film formation via an organometallic route

Abstract

Crystalline, uniform, adherent, ultrathin films of TiO2 were deposited onto OH-functionalized organic self-assembled monolayers (SAMs) on single-crystalline Si at low-temperature (<100 °C) from anhydrous ethanolic solutions of titanium isopropoxide. The films were identified as TiO2 by x-ray photoelectron spectroscopy, electron diffraction, and energy-dispersive x-ray microanalysis. Transmission electron microscopy showed the films to be uniform in thickness (2 ± 0.5 nm) and continuous. On bare Si, in contrast, there was no evidence of TiO2 deposition under identical conditions. Unlike the anatase films deposited on SAMs from aqueous solutions (described in the preceding paper), the electron diffraction patterns of the films deposited from alkoxide solutions suggest that they were the rutile phase. It is suggested that the functionalized SAMs enable the anchoring of the Ti alkoxide and initiate the formation of an adherent oxide film, and that they are sufficiently uniform that the resulting film is continuous and uniform in thickness.