Effect of O2 concentration on metal–insulator transition properties of vanadium oxide thin films prepared by radio frequency magnetron sputtering

Lee, Jang Woo; Min, Su Ryun; Cho, Han Na; Chung, Chee Won

doi:10.1016/j.tsf.2007.03.066

Cited by 9 publications

(6 citation statements)

References 12 publications

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“…The RF sputtering technique oen offers amorphous vanadium oxide lm deposited at room temperature. 36,37 Crystallinity can be achieved at elevated substrate temperatures, [38][39][40][41] by post annealing 36,[40][41][42][43] or an increase in the oxygen partial pressure. 37,41 The FESEM photomicrographs of the thin lms deposited on a silicon substrate with thicknesses of 21 nm, 156 nm, and 211 nm grown at 100 W, 500 W and 700 W, respectively, for a constant duration of 1 h are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Study of the structural, thermal, optical, electrical and nanomechanical properties of sputtered vanadium oxide smart thin films

et al. 2015

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Vanadium oxide thin films were grown on both quartz and Si(111) substrates utilizing pulsed RF magnetron sputtering technique at room temperature with RF power at 100 W to 700 W. The corresponding thicknesses of the films were increased from 27.5 nm to 243 nm and 21 nm to 211 nm as RF power increased from 100 W to 700 W for quartz and silicon substrates, respectively. X-ray diffraction and field emission scanning electron microscopy were carried out to investigate the phase and surface morphology of the deposited films. Electronic structure and vanadium oxidation states of the deposited films were investigated thoroughly by X-ray photoelectron spectroscopy. As-grown films show stoichiometric vanadium oxide only where vanadium is in V 5+ and V 4+ states. Phase transition of vanadium oxide films were investigated by differential scanning calorimetric technique. The reversible i.e. smart transition was observed in the region from 337 °C to 343 °C. Average hemispherical emittance of the deposited vanadium oxide films was evaluated by an emissometer in the wavelength range of 3 µm to 30 µm. The sheet resistance of the deposited films was measured by two-probe method and data were in the range of 10 6 to 10 5 Ω/square. Optical properties of the films such as solar transmittance, solar reflectance and solar absorptance as well as optical constants e.g. optical band gap were also evaluated. Finally, mechanical properties such as nanohardness and Young's modulus at microstructural length scale were evaluated employing nanoindentation technique with continuous stiffness mode.

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Section: Resultsmentioning

confidence: 99%

Study of the structural, thermal, optical, electrical and nanomechanical properties of sputtered vanadium oxide smart thin films

et al. 2015

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“…In VO 2 thin films, and many other thin films of correlated oxides with MITs, the thickness of the deposited films can strongly modify their MIT properties (e.g., transition magnitude, critical temperature, and hysteresis width), − which may also depend on additional deposition parameters (deposition method, temperature, oxidation pressure, lattice mismatch, strain, etc. ) − further complicating the picture. Thus, growth dynamics and dislocation formation become a major hurdle that may slow down research and application realization.…”

Section: Introductionmentioning

confidence: 99%

Ultrathin Films of VO₂ on r-Cut Sapphire Achieved by Postdeposition Etching

Yamin¹,

Wissberg²,

Cohen

et al. 2016

ACS Appl. Mater. Interfaces

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The metal-insulator transition (MIT) properties of correlated oxides thin films, such as VO2, are dramatically affected by strain induced at the interface with the substrate, which usually changes with deposition thickness. For VO2 grown on r-cut sapphire, there is a minimum deposition thickness required for a significant MIT to appear, around 60 nm. We show that in these thicker films an interface layer develops, which accompanies the relaxation of film strain and enhanced electronic transition. If these interface dislocations are stable at room temperature, we conjectured, a new route opens to control thickness of VO2 films by postdeposition thinning of relaxed films, overcoming the need for thickness-dependent strain-engineered substrates. This is possible only if thinning does not alter the films' electronic properties. We find that wet etching in a dilute NaOH solution can effectively thin the VO2 films, which continue to show a significant MIT, even when etched to 10 nm, for which directly deposited films show nearly no transition. The structural and chemical composition were not modified by the etching, but the grain size and film roughness were, which modified the hysteresis width and magnitude of the MIT resistance change.

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“…Divanadium pentaoxide (V 2 O 5 ) and vanadium dioxide (VO 2 ) are the two main oxide phases, and several chemical and physical methods have been used to obtain such oxides 6–11. Among vapor phase techniques CVD offers the opportunity of preparing metal oxide films with good quality and uniformity 6, 9, 12…”

Section: Relative Abundance and M/z Ratio Of The Mass Peaks Obtained mentioning

confidence: 99%

MOCVD of Vanadium Oxide Films with a Novel Vanadium(III) Precursor

Crociani¹,

Carta²,

Natali³

et al. 2011

Chemical Vapor Deposition

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Vanadium forms several oxides with a wide variety of properties and technological applications in the fields of catalysis, solid-state batteries, electrochromic devices, and infrared modulators. [1][2][3][4] The ability of vanadium atoms to possess multiple oxidation states, and the facile conversion between oxides of different stoichiometry, makes the synthesis of pure vanadium oxide phases complicated. [5,6] Divanadium pentaoxide (V 2 O 5 ) and vanadium dioxide (VO 2 ) are the two main oxide phases, and several chemical and physical methods have been used to obtain such oxides. [6][7][8][9][10][11] Among vapor phase techniques CVD offers the opportunity of preparing metal oxide films with good quality and uniformity. [6,9,12] In the CVD of vanadium oxide, VO [16] The best synthetic way consisted in reacting VCl 3 Ã 3THF with Na(OCMe 2-CH 2 OMe) in THF, prepared in-situ from the corresponding alcohol MeOCH 2 CMe 2 OH and Na, at a temperature below À78 8C. After the work-up, a 20% yield of pure [V(OCMe 2-CH 2 OMe) 3 ], as a violet oil, was recovered by sublimation. The complex was characterized by elemental analysis and electron impact mass spectrometry (EIMS).The EI spectrum (see Table 1) is characterized by the presence of the molecular peak M þ (m/z ¼ 360) in 12% relative abundance.The structure of the alcohol, which allows both chelation with the metal and transfers of part of the molecule to the metal, and the presence of the electron-donating methoxy groups, help in stabilizing different ions; the most abundant ions corresponding to species orginated by the loss of at least one alkoxide group.The peaks at 315 m/z (rel. abun. 33%) and at 257 m/z (rel. abun. 97%) can be easily ascribed to the species The other quite abundant peaks at 140 m/z (rel. abun. 88%) and 125 m/z (rel. abun. 95%) are from fragments which contain only part of an alkoxide group; it is reasonable to suppose that, like most of the fragments, they keep a VO 2 core, which is promising for the deposistion of VO x of the desired stoichiometry. We tentatively suggest that the ion at 140 m/z is a radical cationic hydroxy species with the formula [V(OH)OC 4 H 7 ] þ , and the ion at 125 m/z is a vanadyl species with the formula [V(O)OC 3 H 6 ] þ . The second part of the work consisted of using the complex as the precursor for the MOCVD of vanadium oxide films by means of a horizontal, hot-wall reactor set at 550 8C, and using N 2 as the carrier gas and a mixture of O 2 and H 2 O as the reactant gas.First, by setting the flow rate of the reactant gas at 400 sccm we were able to grow vanadium dioxide on Si(100) (sample A) and on fused silica glass substrates (sample A 0 ) in the same run; sample A, which was closer to the entrance

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Effect of O2 concentration on metal–insulator transition properties of vanadium oxide thin films prepared by radio frequency magnetron sputtering

Cited by 9 publications

References 12 publications

Study of the structural, thermal, optical, electrical and nanomechanical properties of sputtered vanadium oxide smart thin films

Study of the structural, thermal, optical, electrical and nanomechanical properties of sputtered vanadium oxide smart thin films

Ultrathin Films of VO₂ on r-Cut Sapphire Achieved by Postdeposition Etching

MOCVD of Vanadium Oxide Films with a Novel Vanadium(III) Precursor

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Effect of O2 concentration on metal–insulator transition properties of vanadium oxide thin films prepared by radio frequency magnetron sputtering

Cited by 9 publications

References 12 publications

Study of the structural, thermal, optical, electrical and nanomechanical properties of sputtered vanadium oxide smart thin films

Study of the structural, thermal, optical, electrical and nanomechanical properties of sputtered vanadium oxide smart thin films

Ultrathin Films of VO2 on r-Cut Sapphire Achieved by Postdeposition Etching

MOCVD of Vanadium Oxide Films with a Novel Vanadium(III) Precursor

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Ultrathin Films of VO₂ on r-Cut Sapphire Achieved by Postdeposition Etching