• Title/Summary/Keyword: Vanadium Oxide Thin Films

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A Study on The Fabrication and Electrochemical Characterization of Amorphous Vanadium Oxide Thin Films for Thin Film Micro-Battery (마이크로 박막 전지용 비정질 산화바나듐 박막의 제작 및 전기화학적 특성에 관한 연구)

  • 전은정;신영화;남상철;조원일;윤영수
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.634-637
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    • 1999
  • The amorphous vanadium oxide as a cathode material is very preferable for fabricating high performance micro-battery. The amorphous vanadium oxide cathode is preferred over the crystalline form because three times more lithium ions can be inserted into the amorphous cathode, thus making a battery that has a higher capacity. The electrochemical properties of sputtered films are strongly dependent on the oxygen partial pressure in the sputtering gas. The effect of different oxygen partial pressure on the electrochemical properties of vanadium oxide thin films formed by r.f. reactive sputtering deposition were investigated. The stoichiometry of the as-deposited films were investigated by Auger electro spectroscopy. X-ray diffraction and atomic force microscopy measurements were carried out to investigate structural properties and surface morphology, respectively. For high oxygen partial pressure(>30% ), the films were polycrystalline V$_2$O$_{5}$ while an amorphous vanadium oxide was obtained at the lower oxygen partial pressure(< 15%). Half-cell tests were conducted to investigate the electrochemical properties of the vanadium oxide film cathode. The cell capacity was about 60 $\mu$ Ah/$\textrm{cm}^2$ m after 200 cycle when oxygen partial pressure was 20%. These results suggested that the capacity of the thin film battery based on vanadium oxide cathode was strongly depends on crystallinity.y.

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Humidity-Sensing Properties of RF Sputtered Vanadium Oxide Thin Films (RF 스퍼터된 바나듐 산화막의 습도 감지 특성)

  • Choi, Bok-Gil;Choi, Chang-Kyu;Kim, Sung-Jin
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.55 no.10
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    • pp.475-480
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    • 2006
  • Vanadium oxide thin films (VOx) have been deposited by RF magnetron sputtering from $V_2O_5$ target under different oxygen partial pressure ratios(0%, 10%) and substrate temperatures$(27^{\circ}C,\;400^{\circ}C)$. Crystallographic structure and morphology of the films are studied by XRD and SEM. Humidity-sensing properties of resistive sensors having interdigitated electrode structure are characterized through electrical conduction measurements. The films deposited at room temperature are amorphous whereas the ones deposited above foot are polycrystalline. The sensors show good response to humidity over 20%RH to 80%RH. Vanadium oxide thin films deposited with $0%O_2$ partial pressure at $400^{\circ}C$ exhibit greater sensitivity to humidity change than others.

Fabrication and electrochemical characterization of amorphous vanadium oxide thin films for thin film micro-battery by reactive r.f. sputtering (반응성 r.f. 스퍼터링에 의한 마이크로 박막 전지용 산화바나듐 박막의 제작 및 전기화학적 특성 평가)

  • 전은정;신영화;남상철;윤영수;조원일
    • Journal of the Korean Vacuum Society
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    • v.9 no.1
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    • pp.42-47
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    • 2000
  • The amorphous vanadium oxide thin films for thin-film rechargeable lithium batteries were fabricated by r.f. reactive sputtering at room temperature. As the experimental parameter, oxygen partial pressure was varied during sputtering. At high oxygen partial pressures(>30%), the as-deposited films, constant current charge/discharge characteristics were carried out in 1M $LiPF_6$, EC:DMC+1:1 liquid electrolyte using lithium metal as anode. The specific capacity of amorphous $V_2O_5$ after 200cycles of operation at room temperature was higher compared to crystalline $V_2O_5$. The amorphous vanadium oxide thin film and crystalline film showed about 60$\mu$Ah/$\textrm{cm}^2\mu\textrm{m}$ and about 38$\mu$Ah/$\textrm{cm}^2\mu\textrm{m}$, respectively. These results suggest that the battery capacity of the thin film vanadium oxide cathode strongly depends on the crystallinity.

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Humidity-Sensitive Properties of Vanadium Oxide Thin Films on Sputtering Conditions (스퍼터링 조건에 따른 바나듐 산화막의 감습 특성)

  • Lee, Seung-Chul;Choi, Bok-Gil;Choi, Chang-Gyu;Kwon, Gwang-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11a
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    • pp.448-451
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    • 2004
  • Vanadium oxides have been widely used in a variety of technological applications such electrochromic devices as infrared detectors and are expected as a material suitable for gas sensing applications. Thin films of Vanadium oxide (VOx) have been deposited by r.f magnetron sputtering under different oxygen partial pressure ratios and substrate temperatures. Humidity-sensitive properties of resistive sensors having interdigitated electrode structure are characterized. Our sensors show good response to humidity over 20%RH to 80%RH. Vanadium oxide films deposited with 0% $O_2$ partial pressure at foot exhibit greater sensitivity to humidity change than others.

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Structural and Electrical Properties of Vanadium Oxide Thin Films Annealed in Vacuum (진공 어닐링한 바나듐 산화악의 구조적, 전기적 특성)

  • Choi Bok-Gil;Choi Chang-Kyu;Kwon Kwang-Ho;Kim Sung-Jin
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.1
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    • pp.1-7
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    • 2005
  • Thin films of vanadium oxide(VO/sub x/) were deposited by r.f. magnetron sputtering from V₂O/sub 5/ target with oxygen/(oxygen+argon) partial pressure ratio of 0% and 8% and in situ annealed in vacuum at 400℃ for 1h and 4h. Crystal structure, chemical composition, molecular structure, optical and electrical properties of films were characterized through XRD, XPS, RBS, FTIR, optical absorption and electrical conductivity measurements. The films as-deposited are amorphous, but 0%O₂ films annealed for time longer than 4h and 8% O₂ films annealed for time longer than 1h are polycrystalline. As the oxygen partial pressure is increased the films become more stoichiometric V₂O/sub 5/. When annealed at 400℃, the as-deposited films are reduced to a lower oxide. The optical transmission of the films annealed in vacuum decreases considerably than the as-deposited films and the optical absorption of all the films increases rapidly at wavelength shorter than about 550nm. Electrical conductivity and thermal activation energy are increased with increasing the annealing time and with decreasing the oxygen partial pressure.

Effect of Oxygen Annealing on the Structural and Optical Properties of Sputter-deposited Vanadium Oxide Thin Films (스퍼터링으로 퇴적시킨 바나듐 산화막의 구조적, 광학적 특성에 미치는 산소 어닐링의 효과)

  • 최복길;최창규;김성진
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.12
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    • pp.1003-1010
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    • 2000
  • Thin films of vanadium oxide(VOx) have been deposited by r.f. magnetron sputtering from V$_2$O$\_$5/ target in gas mixture of argon and oxygen. Crystal structure, surface morphology, chemical composition, molecular structure and optical properites of films in-situ annealed in O$_2$ambient with various heat-treatment conditions are characterized through XRD, SEM, AES, RBS, RTIR and optical absorption measurements. The films annealed below 200$\^{C}$ are amorphous, and those annealed above 300$\^{C}$ are polycrystalline. The growth of grains and the transition of vanadium oxide into the higher oxide have been observed with increasing the annealing temperature and time. The increase of O/V ratio with increasing the annealing temperature and time is attributed to the diffusion of oxygen and the partial filling of oxygen vacancies. 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. Also indirect and direct optical band gaps were increased with increasing the annealing temperature and time.

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Investigations on the Structural Properties of Vanadium Oxide Thin Films Prepared by RF Magnetron Sputtering (RF 마그네트론 스퍼터링으로 퇴적시킨 바나듐 산화막의 구조적 특성에 관한 고찰)

  • 최용남;박재홍;최복길;최창규;권광호
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.456-459
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    • 2000
  • Thin films of vanadium oxide(V$O_x$) have been deposited by r.f. magnetron sputtering from $V_2$$O_5$ prget in gas mixture of argon and oxygen. Crystal structure, surface morphology, chemical composition and bonding properties of films in-situ annealed in $O_2$ ambient with various heat-treatment conditions are characterized through XRD, SEM, AES, RBS and FTIR measurements. The filrns annealed below 200 $^{\circ}C$are amorphous, and those annealed above 30$0^{\circ}C$ are polycrystalline. The growth of grains and the transition of vanadium oxide into the higher oxide have been obsenred with increasing the annealing temperature and time. The increase of O/V ratio with increasing the annealing temperature and time is attributed to the diffusion of oxygen and the partial filling of oxygen vacancies. It is observed that the oxygen atoms located on the V-0 plane of $V_2$$O_5$ layer participate more readily in the oxidation process.

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RF-Sputted Vanadium Oxide Thin Films:Effect of Oxygen Partial Pressure on Structural and Electrochemical Properties

  • Park, Yong Jun;Park, Nam Gyu;Ryu, Gwang Seon;Jang, Sun Ho;Park, Sin Jong;Yun, Seon Mi;Kim, Dong Guk
    • Bulletin of the Korean Chemical Society
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    • v.22 no.9
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    • pp.1015-1018
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    • 2001
  • Vanadium oxide thin films with thickness of about 2000 $\AA$ have been prepared by radio frequency sputter deposition using a V2O5 target in a mixed argon and oxygen atmosphere with different Ar/O2 ratio ranging from 99/1 to 90/10. X-ray diffraction and X-ray absorption near edge structure spectroscopic studies show that the oxygen content higher than 5% crystallizes a stoichiometric V2O5 phase, while oxygen deficient phase is formed in the lower oxygen content. The oxygen content in the mixed Ar + O2 has a significant influence on electrochemical lithium insertion/deinsertion property. The discharge-charge capacity of vanadium oxide film increases with increasing the reactive oxygen content. The V2O5 film deposited at the Ar/O2 ratio of 90/10 exhibits high discharge capacity of 100 ${\mu}Ah/cm2-{\mu}m$ along with good cycle performance.

Fabrication and Properties of Vanadium Oxide Thin Films for Microbolometer by using Plasma Atomic Layer Deposition Method (플라즈마 ALD법에 의해 제조된 마이크로볼로미터용 바나듐 산화막의 제작 및 특성)

  • Yun, Hyeong-Seon;Jung, Soon-Won;Jeong, Sang-Hyun;Kim, Kwang-Ho;Choi, Chang-Auck;Yu, Byoung-Gon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.2
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    • pp.156-161
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    • 2008
  • The fabrication of vanadium oxide films directly on Si(100) substrates by plasma atomic layer deposition(ALD) with vanadium oxytriisopropoxide(VOIP) and oxygen as the reactants have been performed at temperature ranging from 250 to $450^{\circ}C$. Growth rate of vanadium oxide was $2.8{\AA}$/cycle at $300{\sim}400^{\circ}C$ defined as ALD acceptable temperature window, Vanadium oxide has been shown the different phases at $250^{\circ}C$ and more than $300^{\circ}C$. It has been confirmed that the phase of the films deposited at $250^{\circ}C\;was\;V_2O_5$ type and that of the films above $300^{\circ}C\;was\;VO_2(T)$ type measured at room temperature, respectively. A large change in resistance and small temperature hysteresis corresponding to a temperature has been observed in the vanadium oxide film deposited at temperature $350^{\circ}C$.

Electrochemical Behavior of Vanadium Trungsten Oxide Thin Films Deposited by Sputtering (스퍼터링으로 증착한 바나듐 텅스텐 산화물 박막의 전기화학적 거동)

  • 박영신;이병일;주승기
    • Journal of the Korean institute of surface engineering
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    • v.30 no.2
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    • pp.121-127
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    • 1997
  • Vanadium tungsten oxide thin films were formed by RF magnetron sputtering and the effects of tungsten addition on the crystallinity and on the electrochemical behavior were investigated. X-ray analysis revealed that amorphized films could be obtained by tungase addition. In order to investigate the electrochemical behavior of the vanadium tungsten oxide films, electrochemical insertion and extraction of lithium were out in 1m $LiCIO_4$-PC-DME electrolyte using litium metal as a counter electrode. When the tungsten was added to the $V_2O_5$ films, cycling reversibility was considerably improved. Electrochemical test showed the cell capacity of about $70\mu\;Ah/\textrm{cm}^2-\mu\textrm{m}$ when the amount of additive tungseten reached 30 atomic percent. No appreciable degradation of the cell capacity could be observed after hundred cycles of insertion and extration od Li.

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