Growth of epitaxial sodium-bismuth-titanate films by metal-organic chemical vapor phase deposition

• Published in: Thin solid films 2011-10, Vol.520 (1), p.239-244
• Main Authors: Schwarzkopf, J., Schmidbauer, M., Duk, A., Kwasniewski, A., Anooz, S. Bin, Wagner, G., Devi, A., Fornari, R.
• Format: Article
• Language: English
• Subjects: Ceramics; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Cross-disciplinary physics: materials science; rheology; Deposition; Epitaxial growth; Exact sciences and technology; High resolution X-ray diffraction; Lead-free ferroelectrics; Materials science; Metal-organic chemical vapor deposition; Methods of deposition of films and coatings; film growth and epitaxy; Phase transformations; Phase transitions; Phases; Physics; Theory and models of film growth; Thin films; Toluene; Vapor phases
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2011.07.050

The liquid-delivery spin metal-organic chemical vapor phase deposition method was used to grow epitaxial sodium-bismuth-titanate films of the system Bi 4Ti 3O 12 + xNa 0.5Bi 0.5TiO 3 on SrTiO 3(001) substrates. Na(thd), Ti(O iPr) 2(thd) 2 and Bi(thd) 3, solved in toluene, were applied as source materials. Depending on the substrate temperature and the Na/Bi ratio in the gas phase several structural phases of sodium-bismuth-titanate were detected. With increasing temperature and/or Na/Bi ratio, phase transitions from an Aurivillius phase with m = 3 to m = 4 via an interleaved state with m = 3.5, and, finally, to Na 0.5Bi 0.5TiO 3 with perovskite structure ( m = ∞) were established. These phase transitions proceed at remarkably lower temperatures than in ceramics or bulk crystals for which they had been exclusively observed so far.