Impact of growth temperature on the crystal habits, forms and structures of VO2 nanocrystals

Löffler, Stefan; Auer, Erwin; Weil, Mat­thias; Lugstein, Alois; Bertagnolli, E.

doi:10.1007/s00339-010-5940-5

Cited by 5 publications

(6 citation statements)

References 21 publications

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“…11,[65][66][67] Consequently it is of great importance to develop efficient methods to prepare such nanoparticles in large quantities and over extended surfaces. In fact, there have been numerous prior studies on VO 2 -based nanoparticles, and recent investigations have been conducted with hydrothermal/solvothermal/colloidal techniques, 27,49,50,64, vapor transport, 56,[109][110][111][112][113][114][115] anodization, 116 polymer-assisted deposition, 117,118 and templating. 29,119 References to earlier studies on the manufacturing of nanostructured VO 2 -based materials can be found elsewhere.…”

Section: Introductionmentioning

confidence: 99%

Thermochromic VO2 nanorods made by sputter deposition: Growth conditions and optical modeling

Namura

Suzuki

et al. 2013

Journal of Applied Physics

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Thermochromic VO 2 nanorods made by sputter deposition: Growth conditions and optical modeling. Reactive dc magnetron sputtering onto glass-based substrates yielded deposits of thermochromic VO 2 with well-developed nanorods and nanowires. Their formation was promoted by high substrate temperature (above ~500 °C), sufficient film thickness, proper inlet of the reactive gas, dispersed gold "seeds" and pronounced substrate roughness. Rutherford back scattering ascertained mass thicknesses, scanning electron microscopy depicted the nanostructures, and glancing incidence Xray diffraction proved that single-phase VO 2 was normally formed. Journal of Applied PhysicsSpectrophotometric measurements of total and diffuse transmittance and reflectance on VO 2 thin films, at room temperature and ~100 °C, allowed us to determine complex dielectric functions below and above the "critical" temperature for thermochromic switching (~68 °C). These data were then used in computations based on the Bruggeman effective medium theory applied to randomly oriented prolate spheroidal structural units to derive the optical properties of the deposits.Experimental and computed data on spectral absorptance were found to be in good qualitative agreement.

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Section: Introductionmentioning

confidence: 99%

Thermochromic VO2 nanorods made by sputter deposition: Growth conditions and optical modeling

Namura

Suzuki

et al. 2013

Journal of Applied Physics

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“…66 Along this line, heating the vanadium-including precursors at a relatively higher temperature usually leads to the formation of VO 2 (R). For example, when using the traditional solid-state reaction routes, such as the sol-gel route, 67 direct annealing vanadium-including precursors, 68 and vapor transport method, 69 etc., all lead to the formation of VO 2 (M). Moreover, VO 2 (R) has V 4+ with a valence state of +4, which is one of the middle valence states of elemental vanadium, which covers the valence states of +2, +3, +4, and +5.…”

Section: Synthesis Of Vo 2 (M) As the Prototype Metal-insulator Trans...mentioning

confidence: 99%

Design of vanadium oxide structures with controllable electrical properties for energy applications

2013

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The electrical properties of inorganic materials has been a long-standing pursued research topic, and successfully controlling the electrical property of an inorganic material has attracted significant attention for a wide range of energy-related applications, covering energy storage, energy conversion and energy utilization. During the few past decades, vanadium oxides have been studied to gain a clear picture of how microstructural characteristics generating the e-e correlations influence the electronic structure of a material, through which the charge concentration, electrical conductivity as well as the metal-insulator transition (MIT), etc., can be precisely controlled, giving promising signs for constructing energy-related devices. In this review, we present an extensive review of the engineering of the microstructures of vanadium oxides with control of their electrical properties, and with attempts to rationally construct energy-related devices, such as aqueous lithium ion batteries, supercapacitors for energy storage, and thermoelectric generators for energy conversion. Furthermore, the MIT performance of vanadium oxides has also seen tremendous advantages for the applications of "smart windows" and magnetocaloric refrigerators for energy utilization. Collectively, progresses to date suggest that in vanadium oxide systems, the electrical properties, including electrical conductivity, carrier concentrations, and the MIT performance, were all strongly dependent on the microstructural characteristics at the atomic scale, which have presented extensive promising energy applications covering energy storage, energy conversion and energy utilization.

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“…In fact, many approaches have been developed to achieve VO 2 (M) MNWs. In most of the cases, the proposed methods resulted in relatively low yield (i.e., surface density) for the micro/nanowires [11,12]. As a remedial solution, roughening the substrate surface, patterning it, or using epitaxial growth were proposed [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

“…In most of the cases, the proposed methods resulted in relatively low yield (i.e., surface density) for the micro/nanowires [11,12]. As a remedial solution, roughening the substrate surface, patterning it, or using epitaxial growth were proposed [11][12][13][14]. However, these approaches are either not suitable for optical applications (roughness and patterning), or not applicable for large-scale production (epitaxy).…”

Section: Introductionmentioning

confidence: 99%

Substrate Temperature-Dependent Structural, Optical, and Electrical Properties of Thermochromic VO2(M) Nanostructured Films Grown by a One-Step Pulsed Laser Deposition Process on Smooth Quartz Substrates

Hendaoui

2021

Advances in Condensed Matter Physics

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Thermochromic M-phase vanadium dioxide VO2(M) films with different morphologies have been grown directly on smooth fused quartz substrates using low deposition rate pulsed laser deposition without posttreatment. When the substrate temperature was increased in the range 450°C–750°C, better (011) texturization of VO2(M) films was observed along with an enhancement of their crystallinity. Morphology evolved from small-grained and densely packed VO2(M) grains at 450°C to less packed micro/nanowires at 750°C. Mechanisms behind the crystallinity/morphology evolution were discussed and correlated with the effect of the temperature on the diffusion of the adatoms as well as on the V5+ valence states content in VO2(M) films. Resistivity measurements as a function of temperature revealed that the insulator-to-metal transition features of VO2(M) films (i.e., transition temperature (TIMT), resistivity variation (ΔR), hysteresis width (ΔH), and transition sharpness (ΔT)) are strongly dependent on the processing temperature. In terms of optical properties, it was found that the open (i.e., porous) structure of the films achieved at high temperature induced an improvement of their luminous transmittance. Simultaneously, the enhancement of the films crystallinity with the temperature resulted in better IR modulation ability. The present contribution provides a one-step process to control the morphology of VO2(M) films grown on smooth quartz substrates for applications as switches, memory devices, and smart windows.

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Impact of growth temperature on the crystal habits, forms and structures of VO2 nanocrystals

Cited by 5 publications

References 21 publications

Thermochromic VO2 nanorods made by sputter deposition: Growth conditions and optical modeling

Thermochromic VO2 nanorods made by sputter deposition: Growth conditions and optical modeling

Design of vanadium oxide structures with controllable electrical properties for energy applications

Substrate Temperature-Dependent Structural, Optical, and Electrical Properties of Thermochromic VO2(M) Nanostructured Films Grown by a One-Step Pulsed Laser Deposition Process on Smooth Quartz Substrates

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