Raman spectroscopic studies of amorphous vanadium oxide thin films

Lee, Se-Hee; Cheong, Hyeonsik; Seong, M. J.; Liu, Ping; Tracy, C. Edwin; Mascarenhas, A.; Pitts, Jennifer; Deb, S. K.

doi:10.1016/j.ssi.2003.08.022

Cited by 274 publications

(120 citation statements)

References 18 publications

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“…Additionally, XRD analysis gave Figure 3 displays the Raman spectra of V 2 O 5 coatings deposited on FTO glass substrates for gas precursor ratio of VCl 4 :H 2 O 1:7 at 450, 500, and 550 • C. The peak positions agree with the literature spectra to within ±2 cm −1 . The high-frequency Raman peak at 995 cm −1 corresponds to the terminal oxygen (V=O) stretching mode, which results from unshared oxygen [25]. Peaks at 530 and 705 cm −1 are attributed to stretching modes of the V-O-V bridging bonds, with the bending motions of these bonds assigned to 486 cm −1 [26].…”

Section: Structurementioning

confidence: 99%

Using an Atmospheric Pressure Chemical Vapor Deposition Process for the Development of V2O5 as an Electrochromic Material

Vernardou

2017

Coatings

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Vanadium pentoxide coatings were grown by atmospheric pressure chemical vapor deposition varying the gas precursor ratio (vanadium (IV) chloride:water) and the substrate temperature. All samples were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, cyclic voltammetry, and transmittance measurements. The water flow rate was found to affect the crystallinity and the morphological characteristics of vanadium pentoxide. Dense stacks of long grains of crystalline oxide are formed at the highest amount of water utilized for a substrate temperature of 450 • C. Accordingly, it was indicated that for higher temperatures and a constant gas precursor ratio of 1:7, the surface morphology becomes flattened, and columnar grains of uniform size and shape are indicated, keeping the high crystalline quality of the material. Hence, it was possible to define a frame of operating parameters wherein single-phase vanadium pentoxide may be reliably expected, including a gas precursor ratio of 1:7 with a substrate temperature of >450 • C. The as-grown vanadium pentoxide at 550 • C for a gas precursor ratio of 1:7 presented the best electrochemical performance, including a diffusion coefficient of 9.19 × 10 −11 cm 2 ·s −1 , a charge density of 3.1 mC·cm −2 , and a coloration efficiency of 336 cm 2 ·C −1 . One may then say that this route can be important for the growth of large-scale electrodes with good performance for electrochromic devices.

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Section: Structurementioning

confidence: 99%

Using an Atmospheric Pressure Chemical Vapor Deposition Process for the Development of V2O5 as an Electrochromic Material

Vernardou

2017

Coatings

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“…Transition metal oxides (TMOs) in thin-film configuration with diverse structures and chromogenic properties have been the foci of the research community in the outlook of their potential applications in the current science and technology [6]. Among the other chromogenic materials, vanadium pentoxide (V 2 O 5 ) in thin-film configuration is one of the TMOs, which has been receiving much attention owing to its quite motivating structural, chemical and chromogenic properties and exceptional industrial applications such as electrochromic devices and optical memory devices [7][8][9]. Most of the researchers have prepared thin films of V 2 O 5 on various solid substrates by different thin-film deposition techniques and investigated their microstructural, optical, electrochromic and electrochemical properties in detail [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic and electrochromic properties of activated reactive evaporated nano-crystalline V2O5 thin films grown on flexible substrates

2013

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Vanadium pentoxide (V 2 O 5 ) thin films were grown on indium tin oxide-coated flexible Kapton substrates by homebuilt activated reactive evaporation technique. Film depositions were carried out at optimised oxygen partial pressure of 1 × 10 −3 Torr and plasma power of 8 W, and we investigated their microstructural and optoelectrochromic properties as a function of substrate temperature. The V 2 O 5 films grown at T s = 473 K exhibited a nano-crystalline nature as evidenced from X-ray diffraction, atomic force microscopy and Raman studies. The nanocrystalline films composed of vertical elliptical-shaped grainy morphology demonstrated a high optical transmittance of 75% with an estimated optical bandgap of 2.38 eV. The dry lithiated nano-crystalline V 2 O 5 films demonstrated an optical modulation of 36.1% with a coloration efficiency value of 26.2 cm 2 /C at a wavelength of 550 nm. As-deposited nano-crystalline V 2 O 5 thin films demonstrated a constant discharge capacity of about 60 μAh cm −2 μm −1 for a few cycles at room temperature in the potential window of 4.0 to 2.5 V.

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“…This is understandable as a relaxation of the amorphous state upon release of pressure. A comparison of the vibrational spectra of the samples recovered from high pressure with that reported [31] for vapor-deposited a-V 2 O 5 is in order. The vapor-deposited a-V 2 O 5 exhibited prominent peaks at 520, 650, 932 and 1027 cm -1 .…”

Section: Resultsmentioning

confidence: 97%

“…Diamond-anvil cell based Raman and X-ray diffraction measurements have revealed only the α-β transition occurring around 6-7 GPa [28,29]. It may also be pointed out that in V 2 O 5 a glassy/ amorphous state, formed by splat-cooling [30] (bulk) and physical vapor deposition [31] The pattern labelled R-53 is that of the recovered sample at ambient pressure after subjecting it to 53 GPa.…”

Section: Resultsmentioning

confidence: 99%

Polyamorphism in network structures

Arora

2012

J. Phys.: Conf. Ser.

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Abstract. Reports of high-density amorphous forms of ice, quartz and Si have intensified the search for amorphous polymorphs in other systems. The network structures that exhibit pressure-induced amorphization are interesting from the point of view of polyamorphism. Recent in-situ high pressure Raman scattering and synchrotron x-ray diffraction studies on negative thermal expansion material zirconium tungstate have revealed an amorphous to amorphous transition at 19 GPa. The transition was identified for the discontinuities in the structural parameters such as position and height of the first peak of the structure factor and that in the tungstate internal vibrational mode frequency. Another compound, vanadium pentaoxide that forms a glass during melt-quenching, is also found to turn amorphous at 40 GPa, pointing to a possibility of polyamorphism.

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Raman spectroscopic studies of amorphous vanadium oxide thin films

Cited by 274 publications

References 18 publications

Using an Atmospheric Pressure Chemical Vapor Deposition Process for the Development of V2O5 as an Electrochromic Material

Using an Atmospheric Pressure Chemical Vapor Deposition Process for the Development of V2O5 as an Electrochromic Material

Spectroscopic and electrochromic properties of activated reactive evaporated nano-crystalline V2O5 thin films grown on flexible substrates

Polyamorphism in network structures

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