Morphology of phase-separated VO2 films deposited on TiO2-(001) substrate

• Published in: Materials research bulletin Vol. 102; pp. 289 - 293
• Main Authors: Cho, Youngji, Aritomi, Shodai, Kanki, Teruo, Kinoshita, Koichi, Endo, Noriaki, Kondo, Yukihito, Shindo, Daisuke, Tanaka, Hidekazu, Murakami, Yasukazu
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.06.2018
• Subjects: A. Interfaces; A. Thin films; B. Phase transition; C. Transmission electron microscopy (TEM); CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRYSTAL DEFECTS; CRYSTALLOGRAPHY; DEPOSITION; GRAIN ORIENTATION; MONOCLINIC LATTICES; MORPHOLOGY; PHASE TRANSFORMATIONS; STRAINS; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; TITANIUM OXIDES; TRANSMISSION ELECTRON MICROSCOPY; VANADIUM OXIDES; C. Transmission electron microscopy (TEM); B. Phase transition; A. Thin films; A. Interfaces
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/j.materresbull.2018.02.030

[Display omitted] •Phase separation in VO2 films at room temperature was studied by TEM.•Tetragonal phase with a zig-zag interface was observed in the neighborhood of the VO2/TiO2 boundary.•The peculiar interface could be explained by the crystallographic relationship between the monoclinic and tetragonal phases. The basic morphology of phase-separated VO2 films, in which the tetragonal (metallic) phase coexists with the monoclinic (insulating) phase, was studied using transmission electron microscopy. While the phase transformation temperature in an unstrained crystal is approximately 340 K, it was observed that at 298 K, elastic strain (caused by lattice mismatch with the TiO2-(001) substrate) stabilized the tetragonal phase near the VO2/TiO2 boundary. The observed zig-zag-shaped interface of the tetragonal phase was explained by the crystallographic orientation relationship between the tetragonal and monoclinic phases. The observations provide valuable information for future applications of VO2 films.