Epitaxial Growth of Iron and Indium Oxide Thin Films on Sapphire R-Plane with a Regular Relief

Аннотация

The formation of a terrace-step surface nanostructure disoriented with respect to the R-plane on sapphire crystals is studied. The possibility of the formation of atomically smooth steps with a height about 0.34 nm is shown. This size corresponds to the interplanar distance of 0.34 nm along the direction [012] in a sapphire crystal. The substrates prepared in such a way are used in the course of the epitaxy of Fe₂O₃ and In₂O₃ films. A method of a high-temperature oxidation of previously deposited iron and indium films under atmospheric conditions is used. It is shown that the structural and geometrical similarity of Fe₂O₃ and sapphire crystal lattices promotes the growth of epitaxial films aligned with respect to the substrate. It is determined that the stress occurring in the growing In₂O₃ films in the course of oxidation and solid-phase epitaxy, as well as owing to a discrepancy between the lattice parameters at the film–substrate interface, is insufficient for the formation of the metastable rhombohedral In₂O₃ phase. The influence of terrace-step nanostructure of the surface of substrates at the initial stages of the growth of epitaxial films is discussed.