Electrochromic properties of radio frequency magnetron sputter deposited mixed Nb2O5:MoO3 (95:5) thin films cycled in H+ and Li+ ions

Usha, N.; Sivakumar, R.; Sanjeeviraja, C.

doi:10.1016/j.mssp.2014.09.043

Cited by 30 publications

(14 citation statements)

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“…The observed roughness values are consisted with values reported for both amorphous Nb2O5 [25,50] and Mo doped Nb2O5 [29,30,51]. The increase in roughness, alongside increases in WMo, can be correlated directly with decreases in PO2 from 0.7 to 0.5 mTorr.…”

Section: Measurement Of the Films' Surface Roughness As Listed Insupporting

confidence: 77%

“…For WMo<100 W, both n(λ) and k(λ) demonstrate behaviors analogous to dielectric, wide band gap semiconductors, with k(λ) < 0.01 for λ > 400 nm. For WMo=100 W, a marked increase in k, where k550=0.02, is noted as a result of energy loss via electron-impurity and electron-electron interaction related to the presence of oxygen vacancies associated with the presence of 3% of the Mo 5+ cation, as measured via XPS (Figure 3, Figure 4) [30,54]. WMo=100 W, where n increases slightly as a potential result of an increase in electronic polarizability or density attributed to the formation of significant quantities of the Mo 5+ cation [56].…”

Section: Measurement Of the Films' Surface Roughness As Listed Inmentioning

confidence: 94%

“…For instance, both Nb2O5 and MoO3 are of particular interest concerning applications in optics due to their respectively high refractive index values of 2.34 [23][24][25] and 2.14 [26,27] at λ=550 nm and wide optical gaps, Eg,Nb2O5 ~ 3.6 [24] and Eg,MoO3~ 3.2 eV [27], rendering both materials transparent throughout visible wavelengths (450 ≤ λ ≤ 700 nm). Additionally, studies by Schmitt et al [28] and Usha et al [29,30] reported excellent electrochromic properties for sol-gel based, and RF deposited Nb2O5:MoO3 mixtures, respectively. Schmitt et al reported a coloration efficiency of 21.5 cm 2 /C for Nb2O5 doped with 0.4% MoO3 [28].…”

Section: Introductionmentioning

confidence: 98%

“…Schmitt et al reported a coloration efficiency of 21.5 cm 2 /C for Nb2O5 doped with 0.4% MoO3 [28]. Later work performed by Usha et al exploring the electrochromic properties of Nb2O5:MoO3 thin films reported maximum coloration efficiencies of 51.94 cm 2 /C and 69.80 cm 2 /C with ratios of 90:10 and 95:5, respectively [29,30]. Furthermore, mixtures of stoichiometric Nb2O5 and MoO3, deposited via RF sputtering, had been explored by Usha et al due to their potential n-type conductivity as a result of lattice substitution of Mo 6+ for Nb 5+ [29,31].…”

Section: Introductionmentioning

confidence: 99%

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Hybrid co-deposition of molybdenum doped niobium pentoxide (NbxMoyOz) thin films

Murphy

Moreno-Tarango

Ramana

et al. 2016

Journal of Alloys and Compounds

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Mixed valent thin films, consisting of optically absorbing metallic cations within a dielectric matrix, possess a variety of optical and electronic properties that can be tailored through variation of dopant concentration and chemistry. This work details the reactive magnetron codeposition of mixed valent NbxMoyOz thin films, systematically doped with optically absorbing Mo 5+ cations, through adjustment of the molybdenum source power. Control over the concentration the Mo 5+ valence state was achieved through decreases in the oxygen partial pressure facilitated via oxygen chemisorption by the molybdenum sputter flux at power levels of 0, 20, 40, 60, 80, and 100 W, while the Nb source was operated concurrently at a constant sputter power of 200 W. The resulting films, roughly 100 nm in thickness, were characterized using variable angle spectroscopic ellipsometry as well as x-ray photoelectron spectroscopy in order to derive a process-property relationship among molybdenum source power and its effects on the refractive index, extinction coefficient, optical band gap, as influenced by the relative concentrations of Mo 5+ , Mo 6+ , and Nb 5+ cations. Increases in the molybdenum source power from 0 to 100 W allow for tailorability of the refractive index, 2.29 ≤ n550 ≤ 2.34, extinction coefficient, 0.00 ≤ k550 ≤ 0.02, and optical band gap, 3.05≤ Eg ≤ 3.48 eV. The co-deposition procedure used within this work affords the ability to systematically adjust the content of the absorbing Mo 5+ cations, from 0 to 3 at. %, within a dielectric matrix comprised of MoO3 and Nb2O5, presenting several opportunities in increasing the design-space for both optical coatings and electrochromic devices.

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Section: Measurement Of the Films' Surface Roughness As Listed Insupporting

confidence: 77%

Section: Measurement Of the Films' Surface Roughness As Listed Inmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Hybrid co-deposition of molybdenum doped niobium pentoxide (NbxMoyOz) thin films

Murphy

Moreno-Tarango

Ramana

et al. 2016

Journal of Alloys and Compounds

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“…44 In addition, the variation in intensity of photoluminescence emission peak with Cu dopant is due to the change in surface state density. 45 11. Plot of (n 2 À 1) À1 vs (h) 2 of pure and Cu doped thin films.…”

Section: Photoluminescence Studymentioning

confidence: 99%

Physical properties of electron beam evaporated CdTe and CdTe:Cu thin films

Punitha

Sivakumar

Sanjeeviraja

et al. 2014

Journal of Applied Physics

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In this paper, we report on physical properties of pure and Cu doped cadmium telluride (CdTe) films deposited onto corning 7059 microscopic glass substrates by electron beam evaporation technique. X-ray diffraction study showed that all the deposited films belong to amorphous nature. The average transmittance of the films is varied between 77% and 90%. The optical energy band gap of pure CdTe film is 1.57 eV and it decreased to 1.47 eV upon 4 wt. % of Cu addition, which may be due to the extension of localized states in the band structure. The refractive index of the films was calculated using Swanepoel method. It was observed that the dispersion data obeyed the single oscillator of the Wemple-Didomenico model, from which the dispersion energy (Ed) parameters, dielectric constants, plasma frequency, and oscillator energy (Eo) of CdTe and CdTe:Cu films were calculated and discussed in detail with the light of possible mechanisms underlying the phenomena. The variation in intensity of photoluminescence band edge emission peak observed at 820 nm with Cu dopant is due to the change in surface state density. The observed trigonal lattice of Te peaks in the micro-Raman spectra confirms the p-type conductive nature of films, which was further corroborated by the Hall effect measurement. The lowest resistivity of 6.61 × 104 Ω cm was obtained for the CdTe:Cu (3 wt. %) film.

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Molybdenum Oxides – From Fundamentals to Functionality

et al. 2017

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The properties and applications of molybdenum oxides are reviewed in depth. Molybdenum is found in various oxide stoichiometries, which have been employed for different high-value research and commercial applications. The great chemical and physical characteristics of molybdenum oxides make them versatile and highly tunable for incorporation in optical, electronic, catalytic, bio, and energy systems. Variations in the oxidation states allow manipulation of the crystal structure, morphology, oxygen vacancies, and dopants, to control and engineer electronic states. Despite this overwhelming functionality and potential, a definitive resource on molybdenum oxide is still unavailable. The aim here is to provide such a resource, while presenting an insightful outlook into future prospective applications for molybdenum oxides.

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Electrochromic properties of radio frequency magnetron sputter deposited mixed Nb2O5:MoO3 (95:5) thin films cycled in H+ and Li+ ions

Cited by 30 publications

References 36 publications

Hybrid co-deposition of molybdenum doped niobium pentoxide (NbxMoyOz) thin films

Hybrid co-deposition of molybdenum doped niobium pentoxide (NbxMoyOz) thin films

Physical properties of electron beam evaporated CdTe and CdTe:Cu thin films

Molybdenum Oxides – From Fundamentals to Functionality

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