Structural study of lanthanum nickelate thin films deposited on different single crystal substrates

• Published in: Journal of solid state chemistry 2004-12, Vol.177 (12), p.4616-4625
• Main Authors: Faucheux, Vincent, Pignard, Stéphane, Audier, Marc
• Format: Article
• Language: English
• Subjects: CHEMICAL VAPOR DEPOSITION; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; EPITAXY; Exact sciences and technology; LANTHANUM COMPOUNDS; LAYERS; MAGNESIUM OXIDES; MATERIALS SCIENCE; Metalorganic chemical vapor deposition; Methods of deposition of films and coatings; film growth and epitaxy; MONOCRYSTALS; NICKEL OXIDES; NICKELATES; PEROVSKITE; Physics; POLYCRYSTALS; Ruddlesden–Popper oxide; Structure and morphology; thickness; SUBSTRATES; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; VACANCIES; X-RAY DIFFRACTION
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2004.10.016

Fabrications of La 2 NiO 4 + δ thin film layers by liquid-injection metalorganic chemical vapor deposition were tried on different single crystals substrates: (001)Si, (001)MgO, ( 001 ) LaAlO 3 and ( 001 ) SrTiO 3 . As results of structural characterizations, polycrystalline dendritic layers of La 2 NiO 4 + δ tetragonal (or orthorhombic) phase were observed on (001)Si substrates while layers of a perovskite-like cubic structure were observed on the other single crystal substrates. From a high-resolution TEM study of a layer deposited on (001)MgO, such a perovskite-like cubic structure exhibits many planar structural faults likely similar to planes of oxygen vacancies of the La 2 NiO 4 + δ orthorhombic structure. A thin intermediate epitaxial layer of NiO phase was also identified. Using a X-ray texture diffractometer, the layer structure on (001)MgO, (001) LaAlO 3 and (001) SrTiO 3 was confirmed to be of cubic structure with 〈 100 〉 axes parallel to those of the substrate. The T dependence of the resistivity of a layer deposited on (001)MgO substrate was found to be of a semi-conducting behavior. Trace of plane structural faults in a LaNiO 3 perovskite structure and corresponding to planes of oxygen vacancies similar to those observed in a La 2 NiO 4 + δ structure. ▪