Luisa Whittaker

Depressed Phase Transition in Solution-Grown VO2 Nanostructures

The first-order metal-insulator phase transition in VO(2) is characterized by an ultrafast several-orders-of-magnitude change in electrical conductivity and optical transmittance, which makes this material an attractive candidate for the fabrication of optical limiting elements, thermochromic coatings, and Mott field-effect transistors. Here, we demonstrate that the phase-transition temperature and hysteresis can be tuned by scaling VO(2) to nanoscale dimensions. A simple hydrothermal protocol yields anisotropic free-standing single-crystalline VO(2) nanostructures with a phase-transition temperature depressed to as low as 32 degrees C from 67 degrees C in the bulk. The observations here point to the importance of carefully controlling the stoichiometry and dimensions of VO(2) nanostructures to tune the phase transition in this system.

VO2nanosheets exhibiting a well-defined metal–insulator phase transition

The ultrafast first-order metal–insulator phase transition in VO2 is characterized by a several orders of magnitude change in optical transmittance and electrical conductivity, which makes this material an attractive candidate for use in a wide variety of applications ranging from Mott field-effect transistors to thermochromic coatings and optical waveguides. However, relatively little progress has been achieved in fabricating VO2nanostructures exhibiting a well-defined metal–insulator transition despite the potential attractiveness of such structures as building blocks for novel nanoscale electronic devices. Herein, we present a solution-based approach for the synthesis of monoclinic single-crystalline VO2nanosheets exhibiting a well-defined metal–insulator phase transition by combining the facile hydrothermal reduction of V2O5, an inexpensive and abundant precursor, with an annealing process. The controlled hydrothermal reduction of bulk V2O5 using small molecule aliphatic alcohols and ketones as reducing agents yields metastable nanostructures of VO2(B) that can be readily transformed to monoclinic VO2 exhibiting a sharp metal–insulator phase transition via an annealing process. The morphology and size of the obtained VO2nanostructures are found to depend on the reaction time and concentration of the added structure-directing agent, providing substantial insight into the nanowire formation process.

Temperature and voltage driven tunable metal-insulator transition in individual W x V 1 − x O 2 nanowires

Results from transport measurements in individual

Single-Nanowire Raman Microprobe Studies of Doping-, Temperature-, and Voltage-Induced Metal–Insulator Transitions of WxV1–xO2 Nanowires

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A VO-seeded approach for the growth of star-shaped VO2 and V2O5 nanocrystals: facile synthesis, structural characterization, and elucidation of electronic structure

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Separating electric field and thermal effects across the metal-insulator transition in vanadium oxide nanobeams

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Large-Area Chemically Modified Graphene Films: Electrophoretic Deposition and Characterization by Soft X-ray Absorption Spectroscopy

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Microscopic and Nanoscale Perspective of the Metal−Insulator Phase Transitions of VO2: Some New Twists to an Old Tale

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Distinctive Finite Size Effects on the Phase Diagram and Metal-insulator Transitions of Tungsten-doped Vanadium(IV) Oxide

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VO2 nanosheets exhibiting a well-defined metal―insulator phase transition

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