Metal-Insulator Phase Transition in Quasi-One-Dimensional VO₂ Structures

Figure 2

(a) Temperature-composition phase diagram. (b) Schematic of the tube furnace reactor. Temperature of the reactor is illustrated by red (hot) and blue (cold) colors. Representative morphologies of the growth product observed in accordance with source vapor pressure include nanosheets (left), nanowires (middle), and nanoparticles (right). SEM images of VO₂ nanowires as grown on (c) Si₃N₄, (d) quartz, and (e) c-cut sapphire and r-cut sapphire substrates. The inset in (c) shows SEM image showing the cross sections of three VO₂ nanowires embedded in a Si₃N₄ surface. The inset in (d) shows AFM image of VO₂ nanowires. The inset in (f) shows a high-magnification SEM image, showing the morphology of a VO₂ nanowire with well-defined surfaces at both a tip and a side. Panels (a–f) adapted with permission from [25–29], respectively.

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