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

Figure 9

(a) Structural phase maps (temperature versus annealing time). The shaded background demarcates a pseudo-T-δ phase diagram for . Confocal reflectivity at a 532 nm laser source. The brighter (darker) regions correspond to the insulating (metallic) phase (upper image). (b) Resistance versus temperature for as-grown (red) and reduced (green) nanobeams. (c) Change in vanadium (V)/oxygen (O) compositional ratio as a function of reduction time and their corresponding work functions extracted from ultraviolet photoemission spectroscopy measurements. (d) Electrical resistance as a function of the reduction time for the as-grown and reduced VO₂ nanobeams. The inset shows statistical data of the electrical resistance at room temperature for as-grown VO₂ and reduced VO₂ nanobeams for 1, 5, and 30 min at approximately 400°C under the exposure to hydrogen gas. Panels (a-b) and (c-d) adapted with permission from [38] and [39], respectively.

(a)

(b)

(c)

(d)