The tetragonal-like to rutile structural phase transition in epitaxial VO 2 /TiO 2 (001) thick films
2015; IOP Publishing; Volume: 17; Issue: 11 Linguagem: Inglês
10.1088/1367-2630/17/11/113016
ISSN1367-2630
AutoresHongbo Qiu, Mengmeng Yang, Yongqi Dong, Han Xu, Bin Hong, Yueliang Gu, Yuanjun Yang, Chongwen Zou, Zhenlin Luo, Chen Gao,
Tópico(s)Gas Sensing Nanomaterials and Sensors
ResumoA 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.
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