Direct Correlation of Structural Domain Formation with the Metal Insulator Transition in a VO<sub>2</sub> Nanobeam

Zhang, Shixiong; Chou, Jung Yen; Lauhon, Lincoln J.

doi:10.1021/nl9028973

Cited by 200 publications

(239 citation statements)

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“…Raman spectra from the dark colored regions of the hydrogenated VO 2 nanobeams (blue curve in Figure 1e) are dominated by weak and broad bands, resembling spectra of VO 2 in the rutile phase (R) 24,32 . Baking a previously fully hydrogenated VO 2 nanobeam in air at 250 8 o C for 20 min restores its Raman spectrum to be nearly identical to that of the as-grown monoclinic state, indicating excellent reversibility of the atomic hydrogenation.…”

mentioning

confidence: 98%

Hydrogen Diffusion and Stabilization in Single-Crystal VO₂ Micro/Nanobeams by Direct Atomic Hydrogenation

Lin¹,

Ji²,

Swift³

et al. 2014

Nano Lett.

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We report measurements of the diffusion of atomic hydrogen in single crystalline VO 2 micro/nanobeams by direct exposure to atomic hydrogen, without catalyst. The atomic hydrogen is generated by a hot filament, and the doping process takes place at moderate temperature (373 K). Undoped VO 2 has a metal-to-insulator phase transition at ~340 K between a high -temperature, rutile, metallic phase and a low-temperature, monoclinic, insulating phase with a resistance exhibiting a semiconductor-like temperature dependence.Atomic hydrogenation results in stabilization of the metallic phase of VO 2 micro/nanobeam down to 2 K, the lowest point we could reach in our measurement setup. Optical characterization shows that hydrogen atoms prefer to diffuse along the c-axis of rutile (a-axis of monoclinic) VO 2 , along the oxygen "channels". Based on observing the movement of the hydrogen diffusion front in single crystalline VO 2 beams, we estimate the diffusion constant

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mentioning

confidence: 98%

Hydrogen Diffusion and Stabilization in Single-Crystal VO₂ Micro/Nanobeams by Direct Atomic Hydrogenation

Lin¹,

Ji²,

Swift³

et al. 2014

Nano Lett.

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“…10,25,26 Thermal images of the NB taken at 355 K under an applied 10 μA sinusoidal current are presented in Figure 2. As discussed, periodic domains are indicative of homogeneous substrate adhesion and are clearly observed in the optical image depicted in Figure 2a,b (greyscale image); this domain configuration remained stationary for the duration of the thermoreflectance measurement.…”

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confidence: 99%

Direct Observation of Nanoscale Peltier and Joule Effects at Metal–Insulator Domain Walls in Vanadium Dioxide Nanobeams

et al. 2014

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The metal to insulator transition (MIT) of strongly correlated materials is subject to strong lattice coupling, which brings about the unique one-dimensional alignment of metal−insulator (M−I) domains along nanowires or nanobeams. Many studies have investigated the effects of stress on the MIT and hence the phase boundary, but few have directly examined the temperature profile across the metal−insulating interface. Here, we use thermoreflectance microscopy to create two-dimensional temperature maps of singlecrystalline VO 2 nanobeams under external bias in the phase coexisting regime. We directly observe highly localized alternating Peltier heating and cooling as well as Joule heating concentrated at the M−I domain boundaries, indicating the significance of the domain walls and band offsets. Utilizing the thermoreflectance technique, we are able to elucidate strain accumulation along the nanobeam and distinguish between two insulating phases of VO 2 through detection of the opposite polarity of their respective thermoreflectance coefficients. Microelasticity theory was employed to predict favorable domain wall configurations, confirming the monoclinic phase identification.

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“…The metal-to-insulator transition (MIT) can be further complicated at large strain or high Cr doping that induces another monoclinic structure of VO 2 , the M2 phase (Figure 1.2). [8][9][10][11][12] In recent studies, vanadium dioxide (VO 2 ) has been known that the compressive strain (2.2%) can totally complete the transition of a VO 2 nanowire to the metallic phase at room temperature. [13] However, the electronic nature of the transitions between the M1, M2, and R structural phase has not been explained across the broad phase space.…”

Section: Substrate --------------------------------------------------mentioning

confidence: 99%

“…[14] Insulator phase M1 and M2 and metallic phase R of vanadium dioxide nanowire distinguished by Raman spectra. [15] Raman spectra was measured by heating the vanadium dioxide nanowire. Figure 1.3 [15] shows insulating phase M1and M2 and metallic phase R of the Raman spectra peak.…”

Section: Substrate --------------------------------------------------mentioning

confidence: 99%

Unprecedented Insulator-to-Metal Transition Dynamics by Heterogeneous Catalysis in Pd-Sensitized Single Vanadium Oxide Nanowires

et al. 2013

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In the part 1, Single crystal vanadium dioxide (VO 2 ) nanowires were grown by physical vapor deposition (PVD) under atmospheric pressure and synthesized on a silicon dioxide (SiO 2 ), a sapphire (Al 2 O 3 ) C-plan and a sapphire R-plan as a substrate.The controllable spontaneous conversion of thin films into nanowires for large area production is investigated. The synthesis is found to depend critically on the thickness of V 2 O 5 layer. We have controlled that the nanowires that are single crystal vanadium dioxide can be grown with thickness of V 2 O 5 thin film and also we can synthesize VO 2 nanowires to various directions on the substrate. By using the patterned substrate, we can not only control the numerous VO 2 nanowire morphologies but also fabricate the guided growth of millimeterlong VO 2 nanowires.In the part 2, we report the high effective hydrogen gas sensor based on the metal-to-insulator transition (MIT) by the electro-thermally induced Palladium-nanoparticles-decorated VO 2 nanowire prepared by the efficient and size-controllable growth method originated from V 2 O 5 thin film driven.We have many experiments for improved hydrogen gas detector based on the MIT. First by doping the tungsten we showed that the MIT temperature was reduced to about 40°C. Second by irradiating a well-defined electron beam into the nanowires, we could considerably increase the conductivity up to 4 times with only a modest change in the MIT temperature (< 2°C). When exposed to trace amounts of hydrogen gas in a single nanowire configuration, the enhanced conductivity gave rise to about two times as fast transition to metallic phase even near room temperature (~35°C), by reaching much faster (~3x) a critical current density at which the self-heating initiates. Last, especially Palladium-VO 2 nanowire near-corshell nanostructure shows remarkably large current increase at a temperature 10 °C lower than the MIT temperature in the bulk. This current increase occurs slowly over the duration of several seconds to several tens of seconds, depending on the Pd coverage, temperature, and hydrogen concentration. This novel finding thus mentions the capability of detecting selectively hydrogen of different three gases (O 2 , CO 2 , and ethylene) and has significant implications for the effective engineering the physicochemical properties of vanadium dioxide by a heterogeneous catalytic process.

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Direct Correlation of Structural Domain Formation with the Metal Insulator Transition in a VO₂ Nanobeam

Cited by 200 publications

References 40 publications

Hydrogen Diffusion and Stabilization in Single-Crystal VO₂ Micro/Nanobeams by Direct Atomic Hydrogenation

Hydrogen Diffusion and Stabilization in Single-Crystal VO₂ Micro/Nanobeams by Direct Atomic Hydrogenation

Direct Observation of Nanoscale Peltier and Joule Effects at Metal–Insulator Domain Walls in Vanadium Dioxide Nanobeams

Unprecedented Insulator-to-Metal Transition Dynamics by Heterogeneous Catalysis in Pd-Sensitized Single Vanadium Oxide Nanowires

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Direct Correlation of Structural Domain Formation with the Metal Insulator Transition in a VO2 Nanobeam

Cited by 200 publications

References 40 publications

Hydrogen Diffusion and Stabilization in Single-Crystal VO2 Micro/Nanobeams by Direct Atomic Hydrogenation

Hydrogen Diffusion and Stabilization in Single-Crystal VO2 Micro/Nanobeams by Direct Atomic Hydrogenation

Direct Observation of Nanoscale Peltier and Joule Effects at Metal–Insulator Domain Walls in Vanadium Dioxide Nanobeams

Unprecedented Insulator-to-Metal Transition Dynamics by Heterogeneous Catalysis in Pd-Sensitized Single Vanadium Oxide Nanowires

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Product

Resources

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Direct Correlation of Structural Domain Formation with the Metal Insulator Transition in a VO₂ Nanobeam

Hydrogen Diffusion and Stabilization in Single-Crystal VO₂ Micro/Nanobeams by Direct Atomic Hydrogenation

Hydrogen Diffusion and Stabilization in Single-Crystal VO₂ Micro/Nanobeams by Direct Atomic Hydrogenation