Journal Article

The tetragonal-like to rutile structural phase transition in epitaxial VO2 TiO2 (001) thick films

Gu, Yueliang, Xu, Han, Qiu, Hongbo, Dong, Yongqi, Yang, Yuanjun, Zou, Chongwen, Yang, Memgmeng, Hong, Bin, Luo, Zhenlin, Gao, Chen

2015

Overview

A controllable metal-insulator transition (MIT) of VO2 has been highly desired due to its huge potential applications in memory storage, smart windows or optical switching devices. Recently, interfacial strain engineering has been recognized as an effective approach to tuning the MIT of epitaxial VO2 films. However, the strain-involved structural evolution during the MIT process is still not clear, which prevents comprehensively understanding and utilizing interfacial strain engineering in VO2 films. In this work, we have systematically studied the epitaxial VO2 thick films grown on TiO2 (001) single crystal substrate and the structural transition at the boundary of MIT region. By using in situ temperature-dependent high-resolution x-ray diffractions, a tetragonal-like ('T-like') to 'rutile' structural phase transition is identified during the MIT process. The room-temperature crystal phase of epitaxial VO2 TiO2(001) thick film is clarified to be tetragonal-like, neither strained-rutile phase nor monoclinic phase. The calculated atomic structure of this T-like phase VO2 resembles that of the M1 phase VO2, which has been verified by their similar Raman spectra. More, the crystal lattices of the coexisted phases in the MIT region were revealed in detail. The current findings will not only show some clues on the MIT mechanism study from the structural point of view, but also favor the interface engineering assisted VO2-based devices and applications in the future.

• Publisher: IOP Publishing
• Subject: Atomic structure / Crystal lattices / Crystal structure / Epitaxial growth / Metal-insulator transition / Optical switching / Phase transitions / Physics / Raman spectra / reciprocal space mapping / Room temperature / Rutile / Single crystals / Smart materials / structural phase transition / Substrates / Surface tension / synchrotron radiation x-ray diffraction / Temperature dependence / Thick films / Titanium dioxide / vanadium dioxide / Vanadium oxides / Windows (apertures)