Structural, electrical, and electromagnetic properties of nanostructured vanadium dioxide thin films

Subramanyam, Guru; Shin, Eunsung; Peri, Prudhvi; Katiyar, Ram S.; Naziripour, Golali; Dey, Satadru

doi:10.1016/b978-0-12-822085-6.00005-4

Cited by 4 publications

(12 citation statements)

References 41 publications

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“…Various synthesis methods have provided different characteristic values for VO 2 , including sputtering, sol-gel synthesis, atomic layer deposition, chemical vapor deposition, and pulsed laser deposition (PLD) [5]. The main factors that influence the processing methods are thickness, meta-morphology, impurity, microstructure, and oxygen concentration.…”

Section: Introductionmentioning

confidence: 99%

“…The insulator to metal transition temperature (T c ) depends on the oxygen concentration and the V/O ratio. The doping concentration M adjusts the T c in the V 1−x M x O 2 system, where M is a divalent metal [5]. Specifically, a small amount of tungsten (W) reduces the T c at the expense of reduction on resistances at room temperature [7].…”

Section: Introductionmentioning

confidence: 99%

“…The optical properties of some transition metal oxides are known to be changed reversibly in connection with the phase transition from metallic to semiconductor in the films [5], which is attractive for smart window applications [6][7][8]. V 1−x M x O 2 is the most attractive phase change material because the transition temperature is about 68 °C in the VO 2 and lower for V 1−x M x O 2 films as determined in the visible and near-IR region [5]. The main challenge with the synthesis of V 1−x M x O 2 is the purity, due to closely related phases.…”

Section: Introductionmentioning

confidence: 99%

“…The infrared optical measurements demonstrate low loss in the semi-transparent state, and higher loss is drastically reflective above the transition temperature where it is in a metallic state. In general, the loss depends on 2p electron transfer to the 3d level in the visual electromagnetic region around 400 nm, and in the near-infrared region, caused by the charge motion in electromagnetic waves [5].…”

Section: Introductionmentioning

confidence: 99%

“…In practice, the characteristics of the extinction coefficient (k), index of refraction (n), and other electromagnetic properties largely depend upon the synthesis technique. We have reported on the synthesis, transport, and optical properties of V 1−x M x O 2 thin films in reference [5]. In this paper, we report on the optical properties of V 1−x M x O 2 doped with W, using direct and indirect bandgap data obtained at various temperatures and doping levels.…”

Section: Introductionmentioning

confidence: 99%

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V1−xWxO2 thermochromic films for device applications

et al. 2022

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V1−xWxO2 is known to be a reliable thermochromic material for multiple practical applications due to its insulator to metal transition temperature controlled by W dopping. In this paper, we present electrical and optical properties of V1−xWxO2 thin films synthesized by PLD technique. In this respect, the electrical resistance, the refractive index (n), and extinction coefficient (k) as a function of temperature from 25 to 80 °C and wavelength ranging from 500 to 3000 nm were obtained using conventional 4-probe resistance and ellipsometry methods. The direct and indirect bandgap values at different doping levels and temperatures have been calculated using n and k versus energy data and compared with thermally activated bandgap from electrical resistance. A decrease in direct and indirect bandgaps with temperature and wavelength was observed with doping and temperature. Comparison between thermal and optical bandgap demonstrates that activated thermal bandgap is only comparable with the lowest optical indirect bandgap. Graphical abstract

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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V1−xWxO2 thermochromic films for device applications

et al. 2022

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Transmissive terahertz metasurfaces with vanadium dioxide split-rings and grids for switchable asymmetric polarization manipulation

Serebryannikov

Lakhtakia

Vandenbosch

et al. 2022

Sci Rep

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Metasurfaces containing arrays of thermally tunable metal-free (double-)split-ring meta-atoms and metal-free grids made of vanadium dioxide (VO$$_2$$ 2 ), a phase-change material can deliver switching between (1) polarization manipulation in transmission mode as well as related asymmetric transmission and (2) other functionalities in the terahertz regime, especially when operation in the transmission mode is needed to be conserved for both phases of VO$$_2$$ 2 . As the meta-atom arrays function as arrays of metallic subwavelength resonators for the metallic phase of VO$$_2$$ 2 , but as transmissive phase screens for the insulator phase of VO$$_2$$ 2 , numerical simulations of double- and triple-array metasurfaces strongly indicate extreme scenarios of functionality switching also when the resulting structure comprises only VO$$_2$$ 2 meta-atoms and VO$$_2$$ 2 grids. More switching scenarios are achievable when only one meta-atom array or one grid is made of VO$$_2$$ 2 components. They are enabled by the efficient coupling of the geometrically identical resonator arrays/grids that are made of the materials that strongly differ in terms of conductivity, i.e. Cu and VO$$_2$$ 2 in the metallic phase.

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Transport properties of V1-xWxO2 around the metal insulator transition temperature

Naziripour

Shin²,

Subramanyam³

et al. 2023

International Workshop on Thin Films for Electronics, Electro-Optics, Energy and Sensors 2022

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The transport properties of W-doped thermochromic V1-xWxO2 (x=0 and 0.0074) thin films prepared by pulsed laser deposition were studied to understand the effect of doping on the electrical properties of these films. Temperature dependent magneto-transport measurements (Hall effect) in magnetic fields up to 9 Tesla were performed on thin film vanadium dioxide (VO2) across the Mott metal-insulator transition (MIT). The Hall carrier density increases by 4 orders of magnitude at MIT. The Hall mobility varies little across the MIT and remains low at ~ 0.05 cm 2 /V sec. The majority carriers are electrons. Magneto-resistance is small and positive. Comparison of the three Hall parameters including carrier concentration, conductivity and mobility between various doping levels on both metallic and insulating state are reported and a model has been proposed. A correlation between carrier concentration and conductivity of VO2 films is observed but doesn't exist between carrier concentration and mobility.

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Structural, electrical, and electromagnetic properties of nanostructured vanadium dioxide thin films

Cited by 4 publications

References 41 publications

V1−xWxO2 thermochromic films for device applications

V1−xWxO2 thermochromic films for device applications

Transmissive terahertz metasurfaces with vanadium dioxide split-rings and grids for switchable asymmetric polarization manipulation

Transport properties of V1-xWxO2 around the metal insulator transition temperature

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