Orientation Relationships of SrTiO₃and MgTiO₃Thin Films Grown by Vapor−Solid Reactions on (100) and (110) TiO₂(Rutile) Single Crystals

Abstract

SrTiO3 and MgTiO3 thin films were grown by vapor−solid reactions on TiO2 (rutile) single crystals with different surface orientations. The crystallographic relations between the product phases and the TiO2 substrates were studied by X-ray diffractometry (XRD) and transmission electron microscopy. XRD pole figure analysis revealed more than one orientation relationship for SrTiO3 depending on deposition temperature. All observed orientations have a common [11̄0] SrTiO3 ∥ [001] TiO2 tilt axis. Alternatively, a topotaxial formation of MgTiO3 on the rutile crystals was found. The crystallographic relationships between the reaction products and the TiO2 substrates and their origins as well as the role of crystallography for first phase selection are discussed.

Orientation and Phase Relationships between Titania Films and Polycrystalline BaTiO3 Substrates as Determined by Electron Backscatter Diffraction Mapping

“…In different cases, BaTiO 3 with (001), (110), (119), and (331) orientations grew on (110)‐orientated rutile crystals. The fact that these results differ from similar experiments in which SrTiO 3 is reactively grown on the same substrate suggests that the orientation relationships determined for TiO 2 growth on SrTiO 3 and LaAlO 3 may not apply to TiO 2 to BaTiO 3 16 …”

“…The local phase and orientation relationships determined for TiO 2 on polycrystalline BaTiO 3 substrates are comparable with those established for TiO 2 on single‐crystal SrTiO 3 and LaAlO 3 , 7–17 and this provides confidence in this EBSD‐based technique. Specifically, (001) anatase grows on (001) BaTiO 3 and (100) rutile grows on (111) BaTiO 3 .…”

“…Experimentally, substrate orientation, lattice mismatch, temperature, and deposition rate influence the thermodynamics and kinetics of nucleation and growth in a way that controls the resulting film phase and orientation 18–20 . The most consistent observation in these reports, using different growth techniques and temperatures, is that anatase forms on (100) perovskite surfaces with an orientation relationship of (001) A ||(100) P and [100] A ||[010] P , where A and P denote anatase and perovskite, respectively 7–17 . This is generally ascribed to the formation of a low‐energy interface between the anatase and perovskite, owing to the nearly identical atom arrangement in anatase TiO 2 (001) and perovskite ABO 3 (100).…”

“…Prior research shows that titania films deposited on low‐index, macroscopic, single‐crystal perovskite surfaces (including SrTiO 3 and LaAlO 3 , but not BaTiO 3 ) can form epitaxially as either anatase or rutile 7–17 . Experimentally, substrate orientation, lattice mismatch, temperature, and deposition rate influence the thermodynamics and kinetics of nucleation and growth in a way that controls the resulting film phase and orientation 18–20 .…”

“…Prior research shows that titania films deposited on lowindex, macroscopic, single-crystal perovskite surfaces (including SrTiO 3 and LaAlO 3 , but not BaTiO 3 ) can form epitaxially as either anatase or rutile. [7][8][9][10][11][12][13][14][15][16][17] Experimentally, substrate orientation, lattice mismatch, temperature, and deposition rate influence the thermodynamics and kinetics of nucleation and growth in a way that controls the resulting film phase and orientation. [18][19][20] The most consistent observation in these reports, using different growth techniques and temperatures, is that anatase forms on (100) perovskite surfaces with an orientation relationship of (001) A ||(100) P and [100] A ||[010] P , where A and P denote anatase and perovskite, respectively.…”