PNNL

Abstract

An anatase thin film, TiO2(001), has been grown by metal-organic chemical vapor deposition on a SrTiO3(001) substrate. The electronic and structural properties of the anatase thin film were investigated by x-ray photoelectron spectroscopy (XPS), low energy diffraction (LEED), and x-ray photoelectron diffraction (XPD). Comparisons of the core-level binding energies for O 1s and Ti 2p3/2 photoelectrons was made between anatase and rutile, and were found to be identical for both polymorphs. Structually, the surface gave a (1x1) LEED pattern with a high background, indicating regions of good long-range order. A comparison between experimental XPD data and single-scattering cluster calculations indicate that the surface region is well ordered and fully consistent with a bulk-like anatase crystal termination. This study indicates that anatase is stable and does not undergo a transformation to the rutile polymorph when exposed to atmosphere after film growth or after heating to low temperatures in ultrahigh vacuum.