• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.558-561
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• 2001

Vanadium oxide ($VO_x$) thin films are very good candidate material for uncooled infrared (IR) detectors due to their high temperature coefficient of resistance (TCR) at room temperature. But, the deposition of $VO_x$ thin films showing good electrical properties is very difficult in micro bolometer fabrication process using sacrificial layer removal because of its low process temperature and thickness of thin films less than $1000{\AA}$. This paper presents a new fabrication process of $VO_x$ thin films having high TCR and low resistance. Through sandwich structure of $VO_{x}(100{\AA})/V(80{\AA})/VO_{x}(500{\AA})$ by sputter method and post-annealing at oxygen ambient, we have achieved high TCR more than $-2%/^{\circ}C$ and low resistance less than $10K\Omega$ at room temperature.

• 한국전기전자재료학회논문지
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• 제14권12호
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• pp.1008-1015
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• 2001

Thin films of vanadium oxide(VO$\_$x/) have been deposited by r.f. magnetron sputtering from V$_2$O$\_$5/ target in gas mixture of argon and oxygen. The oxygen/(oxygen+argon) partial pressure ratio is changed from 0% to 8%. Crystal structure, chemical composition, bonding, optical and electrical properties of films sputter-deposited under different oxygen gas pressures are characterized through XPS, AES, RBS, FTIR, optical absorption and electrical conductivity measurements. V$_2$O$\_$5/ and lower oxides co-exist in sputter-deposited films and as the oxygen partial pressure is increased the films become more stoichiometric V$_2$O$\_$5/. The increase of O/V ratio with increasing oxygen gas pressure is attributed to the partial filling of oxygen vacancies through diffusion. It is observed that the oxygen atoms located on the V-O plane of V$_2$O$\_$5/ layer participate more readily in the oxidation process. With increasing oxygen gas pressure indirect and direct optical band gaps are increased, but thermal activation energies are decreased.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2007-2010
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• 2008

Vanadium pentoxide ($V_2O_5$) powder was prepared and mixed with Molybdenum Oxides ($MoM_3$) to form Mo-doped and -undoped $VO_2$ films by a sol-gel method on graphite conductive substrates. X-Ray diffraction (XRD) and scanning electron microscopy (SEM) was used to investigate the chemical compositions and microstructures of the Mo-doped and -undoped $VO_2$ films. The variation of electrical resistance was measured as a function of temperature and stoichiometric composition between vanadium and molybdenum. In this study, it was found that Mo-doped and -undoped $VO_2$ shows the typical negative temperature coefficient (NTC) behavior. As the amount of the molybdenum increases, the electrical resistance of Modoped $VO_2$ film gets reduced under the transition temperature and a linear decrease in the transition temperature is observed. From these experimental results, we can conclude that the electrical resistance behavior with temperature change of $VO_2$ films can be utilized as a self-heating source with the electrical current flowing through the graphite substrate.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
• /
• pp.558-561
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• 2001

Vanadium oxide ($VO_{x}$) thin films are very good candidate material for uncooked infrared (IR) detectors due to their high temperature coefficient of resistance (TCR) at room temperature. But, the deposition of $VO_{x}$ thin films showing good electrical properties is very difficult in micro bolometer fabrication process using sacrificial layer removal because of its low process temperature and thickness of thin films less than 1000${\AA}$. This paper presents a new fabrication process of $VO_{x}$ thin films having high TCR and low resistance. Through sandwich structure of $VO_{x}$(100${\AA}$)/V(80${\AA}$)/$VO_{x}$(500${\AA}$) by sputter method and post-annealing at oxygen ambient, we have achieved high TCR more than -2%/$^{\circ}C$ and low resistance less than $10K\Omega$ at room temperature.

• 대한전자공학회논문지
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• 제16권3호
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• pp.9-18
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• 1979

본 논문에서는 바나디움 주화물을 사용한 새로운 반도체 소자인 C.T.R을 제조하여 그외 전기적 특성을 조사하였다. 그 실험결과는 다음과 같다. (1) 제조될 C.T.R의 저항급변계수 는 3정도였고, (2) 의 값은 환원시간과 급냉시간에 크게 의존하였으며, (3) 의 큰 값을 갖는 C.T.R은 짧은 switching현상을 갖는다.

• 한국표면공학회지
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• 제36권4호
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• pp.329-333
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• 2003

The high-temperature oxidation behavior of Ti39Al-10V alloy that consisted primarily of $\beta$-Ti, ${\gamma}$-TiAl, and $\alpha_2$ $-Ti_3$Al phases was studied. The relatively thick and porous oxide scales formed consisted primarily of an outermost, thin TiO$_2$ layer, and an outer, thin $Al_2$$O_3$-rich layer, and an inner, very thick (TiO$_2$, $Al_2$$O_3$) mixed layer. Vanadium was present uniformly throughout the oxide scale. The formation and subsequent evaporation of V-oxides such as VO, $VO_2$, and $V_2$O$_{5}$ deteriorated oxidation resistance and scale adherence of the TiAl alloy significantly.y.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.343-345
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• 1988

In this paper the fabrication and application of Composite-Thermistor were studied. Composite-Thermistor specimens were made by conventional process. Some compounds of vanadium oxides and semiconductor oxides as a fillers were used to fabricate Composite-Thermistor, and Epoxy Resins are used as a polymer matrix. The results of resistivity-temperature characteristics were measured in the range from -100 ($^{\circ}C$) to 200($^{\circ}C$). The harder polymer, Eccogel series #1365-80 and Spurr Epoxy are more preferable compared to the Eccogel (1365-45) with some fillers.

• Journal of Electrochemical Science and Technology
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• 제7권4호
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• pp.306-315
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• 2016

Amorphous vanadium titanates (aVTOs) are examined for use as a negative electrode in lithium-ion batteries. These amorphous mixed oxides are synthesized in nanosized particles (<100 nm) and flocculated to form secondary particles. The $V^{5+}$ ions in aVTO are found to occupy tetrahedral sites, whereas the $Ti^{4+}$ ions show fivefold coordination. Both are uniformly dispersed at the atomic scale in the amorphous oxide matrix, which has abundant structural defects. The first reversible capacity of an aVTO electrode ($295mAhg^{-1}$) is larger than that observed for a physically mixed electrode (1:2 $aV_2O_5$ | $aTiO_2$, $245mAhg^{-1}$). The discrepancy seems to be due to the unique four-coordinated $V^{5+}$ ions in aVTO, which either are more electron-accepting or generate more structural defects that serve as $Li^+$ storage sites. Coin-type Li/aVTO cells show a large irreversible capacity in the first cycle. When they are prepared under nitrogen (aVTO-N), the population of surface hydroxyl groups is greatly reduced. These groups irreversibly produce highly resistive inorganic compounds (LiOH and $Li_2O$), leading to increased irreversible capacity and electrode resistance. As a result, the material prepared under nitrogen shows higher Coulombic efficiency and rate capability.

• 대한화학회지
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• 제55권1호
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• pp.81-85
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• 2011

이소부탄의 산화탈수소반응(ODH)에 대한 $V_{0.9}Sb_{0.1}O_x$ 촉매계의 5가지 담지체의 촉진효과를 조사하였다. 사용된 5가지 담지체는 감마-알루미나, 알파-알루미나, 실리카-알루미나, 실리카겔, 마그네슘 산화물이다. 촉매는 사용된 담지체에 따라 그 효과가 다르게 나타났다: ${\gamma}-Al_2O_3$ > $\alpha$-$Al_2O_3$ > Si-Al-O> $SiO_2$ $\approx$MgO$\gg$unsupported. V-Sb-O 비율은 별로 촉매 활성과 선택성에 영향을 미치지 않았다. 촉매 성분들이 담지체에 골고루 잘 분포된 이유로 인해 감마-알루미나에 담지된 $V_{0.9}Sb_{0.1}O_x$ 촉매계가 성능이 제일 뛰어났다.

• 한국재료학회지
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• 제31권7호
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• pp.382-385
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• 2021

Well-crystallized vanadium pentoxide V₂O₅ thin films are fabricated on MgO single crystal substrates by using pulsed-laser deposition technique. The linear optical transmission spectra are measured and found to be in a wavelength range from 300 to 800 nm; the data are used to determine the linear refractive index of the V₂O₅ films. The value of linear refractive index decreases with increasing wavelength, and the relationship can be well explained by Wemple's theory. The third-order nonlinear optical properties of the films are determined by a single beam z-scan method at a wavelength of 532 nm. The results show that the prepared V₂O₅ films exhibit a fast third-order nonlinear optical response with nonlinear absorption coefficient and nonlinear refractive index of 2.13 × 10^-10 m/W and 2.07 × 10^-15 cm²/kW, respectively. The real and imaginary parts of the nonlinear susceptibility are determined to be 3.03 × 10^-11 esu and 1.12 × 10^-11 esu, respectively. The enhancement of the nonlinear optical properties is discussed.