Structural characterization of TiO2 films grown on LaAlO3 and SrTiO3 substrates using reactive molecular beam epitaxy

We have studied the microstructure of TiO2 films, grown by reactive molecular beam epitaxy (MBE) on LaAlO3 (LAO) and SrTiO3 (STO) substrates, using a combination of transmission electron microscopy (TEM) and electron energy loss spectrometry (EELS). TiO2 films grew epitaxially in the anatase polymorph and exhibited the crystallographic orientation relation of (001)(010)TiO2||(001)(010)substrate. High-resolution TEM and EELS studies indicated the presence of a cubic TiOx phase at the TiO2/STO interface. Interfacial TiOx phases were eliminated and a sharp TiO2/STO interface was achieved by growing the TiO2 film on a heteroepitaxial STO buffer layer.