HETEROEPITAXIAL GROWTH OF TiO₂, VO₂, AND TiO₂/VO₂ MULTILAYERS BY MOCVD

Abstract

Titanium and vanadium dioxide systems were selected to study the MOCVD process for the growth of oxide epitaxial films. Single-crystal TiO₂ and VO₂ films in single and multilayered configurations have been successfully grown on sapphire (α-AlO₂) single-crystal substrates. Seven distinct epitaxial orientation relationship between the films and the substrates were observed. Discussion on these epitaxial relationships based on the consideration of atomic arrangements of the materials is presented. From our experimental results, we concluded that single layer films (both TiO₂ and VO₂) were grown by the nucleations of three-dimensional clusters. Quantum mechanical calculations of the electronic structures, charge distributions, and energetics of the free substrate surfaces were performed and some results are presented.