THESIS
2021
1 online resource (xii, 117 pages) : illustrations (some color)
Abstract
Vanadium dioxide (VO
2) typically is a strongly correlated material that undergoes a characteristic metal-insulator phase transition at ~341 K. The phase transition is accompanied with notable changes in various properties, enabling the extensive and emerging applications of VO
2-based devices, such as smart windows, Mott field-effect transistors, optical modulators, and thermal actuators. Despite these admiring advances, VO
2 related studies yet suffer from poor control on the fabrication of high-quality VO
2 materials; this is a challenging topic and very significant to numerous promising application requirements. This thesis mainly focuses on the controllable fabrication and property modulation of one-dimensional VO
2 materials, e.g., micro-/nano-scale beams, as well as their advanced app...[
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Vanadium dioxide (VO
2) typically is a strongly correlated material that undergoes a characteristic metal-insulator phase transition at ~341 K. The phase transition is accompanied with notable changes in various properties, enabling the extensive and emerging applications of VO
2-based devices, such as smart windows, Mott field-effect transistors, optical modulators, and thermal actuators. Despite these admiring advances, VO
2 related studies yet suffer from poor control on the fabrication of high-quality VO
2 materials; this is a challenging topic and very significant to numerous promising application requirements. This thesis mainly focuses on the controllable fabrication and property modulation of one-dimensional VO
2 materials, e.g., micro-/nano-scale beams, as well as their advanced applications. Two typical reaction approaches are applied to produce VO
2. Wherein, hydrothermal reactions are used to facilitate the scalable fabrication of VO
2 nanocrystals for macro-scale devices, and chemical vapor deposition reactions are used to fabricate high-quality VO
2 single crystals for the investigation about their phase transition properties. Notably, oxide-assisted growth strategies are applied to the controllable growth of VO
2, where different oxides serve as seed crystals, dopants, or inhibitors in the reactions. The kinetics of the VO
2 growth are thus facilely manipulated in the modified reaction systems, enabling various morphologies and properties of as-grown samples. Consequently, wafer-scale vertically grown VO
2 nanowire arrays and super-aligned VO
2 nanobeam films that can be used for high-performance insect-sized soft robots are successfully fabricated. Furthermore, the as-grown VO
2 single crystals present spatially ordered domain evolution processes and unique phase transition properties, potential for novel device applications such as nanoscale thermometers and single-crystalline actuators with outstanding performance.
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