• Title/Summary/Keyword: Oxygen carrier

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Dependence of the Structural and Electrical Properties of Co-Sputtered Zn-Doped ITO Thin Films on the Composition and Oxygen Partial Pressure

  • Heo, Gi-Seok;Kim, EunMi
    • Journal of the Korean Ceramic Society
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    • v.50 no.4
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    • pp.288-293
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    • 2013
  • Zn-In-Sn-O films were prepared at room temperature by combinatorial RF-magnetron co-sputtering system. The cationic contents of the films were varied using a compositionally combinatorial technique. The effects of the oxygen partial pressure and film compositionon the structural and electrical properties were investigated. The Zn-In-Sn-O films deposited at Ar gas atmosphere showed an amorphous phaseirrespective of the film composition. However, the amorphous Zn-In-Sn-O films with a Zn content below 30.0 at% were converted into a bixbyite type-ITO polycrystalline phase with an increase in the oxygen partial pressure. The resistivity, carrier concentration, and Hall mobility were strongly affected by the oxygen partial pressure and chemical composition of the film. At sufficiently high carrier densities above $5{\times}10^{18}cm^{-3}$, the conduction behavior of amorphous Zn-In-Sn-O film changes from thermally activated to degenerate band conduction accompanied with high mobility.

Performance Estimation and Process Selection for Chemical-Looping Hydrogen Generation System (금속매체 순환식 수소생산 시스템의 성능예측 및 공정선정)

  • Ryu, Ho-Jung;Jin, Gyoung-Tae
    • Transactions of the Korean hydrogen and new energy society
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    • v.16 no.3
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    • pp.209-218
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    • 2005
  • To find a suitable metal component in oxygen carrier particles for chemical-looping hydrogen generation system(CLH), oxygen transfer capacities of metal components were compared and Ni has been selected as the best metal component. The proper operating conditions to achieve high hydrogen generation rate have been investigated based on the chemical-equilibrium composition analysis for water splitting reactor. Moreover, suitable compositions of syngas from gasifier of heavy residue to achieve high energy efficiency have been investigated by calculation of heat of reaction. Based on the selected operating conditions, the best configuration of two interconnected fluidized beds system for the chemical-looping hydrogen generator has been investigated as well.

Transparent ZnO based thin film transistors fabricated at room temperature with high-k dielectric $Gd_2O_3$ gate insulators

  • Tsai, Jung-Ruey;Li, Chi-Shiau;Tsai, Shang-Yu;Chen, Jyun-Ning;Chien, Po-Hsiu;Feng, Wen-Sheng;Liu, Kou-Chen
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.374-377
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    • 2009
  • The characteristics of the deposited thin films of the zinc oxide (ZnO) at different oxygen pressures will be elucidated in this work. The resistivity of ZnO thin films were dominated by the carrier concentration under high oxygen pressure conditions while controlled by the carrier mobility at low oxygen ambiences. In addition, we will show the characteristics of the transparent ZnO based thin film transistor (TFT) fabricated at a full room temperature process with gate dielectric of gadolinium oxide ($Gd_2O_3$) thin films.

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The Oxidation of Hydrazobenzene by Oxygen Catalysed by Co (3MeOsalen) in Methanol

  • Homer Roger B.;Cannon Roderick D.;Kim Stephen S.B.
    • Bulletin of the Korean Chemical Society
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    • v.6 no.2
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    • pp.115-118
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    • 1985
  • The oxidation of hydrazobenzene by oxygen in methanol solution is catalysed by Co(3MeOsalen) which is a synthetic oxygen carrier. The products are trans-azobenzene and water. The rate of the reaction has been studied spectrophotometrically and the rate law established. A mechanism involving a ternary complex of catalyst, hydrazobenzene and oxygen has been proposed.

Comparison of Nitrogen and Oxygen Annealing Effects on the Structural, Optical and Electrical Properties of ALD-ZnO Thin Films (ALD법으로 증착한 ZnO 박막의 열처리 분위기에 따른 구조적, 전기적 특성 비교)

  • Park Y. K.;Park A. N.;Lee C. M.
    • Korean Journal of Materials Research
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    • v.15 no.8
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    • pp.514-517
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    • 2005
  • Effects of nitrogen and oxygen annealing on the carrier concentration, carrier mobility, electrical resistivity and PL characteristics as well as the crystallinity of ZnO films deposited on sapphire substrates by atomic layer deposition (ALD). X-ray diffraction (XRD), Scanning electron microscope (SEM), photoluminescence (PL) analyses, and Hall measurement were performed to investigate the crystallinity, optical properties and electrical properties of the ZnO thin films, respectively. According to the XRD analysis results the crystallinity of the ZnO film annealed in an oxygen atmosphere is better than that of the ZnO film annealed in a nitrogen atmosphere. Annealing undoped ZnO films grown by ALD at a high temperature above $600^{\circ}C$ improves the crystallinity and enhances W emission but deteriorates the electrical conductivity of the flms. The resistivity of the ZnO film annealed particularly at $800^[\circ}C$ in a nitrogen atmosphere is much higher than that annealed at the same temperature in an oxygen atmosphere.

Relationship between Optical Properties Analyzed by Photoluminance of Bonding Structure Analyzed by X-ray Diffractometer (XRD 분석에 의한 결정구조와 PL 분석에 의한 광학적 특성의 상관성)

  • Oh, Teresa
    • Journal of the Semiconductor & Display Technology
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    • v.15 no.1
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    • pp.70-75
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    • 2016
  • GZO films prepared on ITO glasses were annealed at various temperatures in a vacuum condition to research the relationship between oxygen vacancies and optical properties. GZO films after annealing in a vacuum showed the various optical-chemical properties depending on the annealing temperatures and oxygen gas flow rate during the deposition. The oxygen vacancy of GZO film prepared by oxygen gas flows of 22 sccm increased with increasing the annealing temperatures, because of the extraction of oxygen by the annealing. But the intensity of photoluminance of GZO with 22 sccm decreased in accordance with the annealing temperature, because of the reduction of ionized charge carriers. The oxygen vacancy by the extraction of oxygen enhanced a depletion, so the widen depletion had the strong Schottky barrier and the PL intensity due to the low carrier density decreased.

The analysis on TMA gas-sensing characteristics of ZnO thin film sensors (ZnO 막막 센서의 TMA 가스 검지 특성 분석)

  • 류지열;박성현;최혁환;김진섭;이명교;권태하
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.34D no.12
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    • pp.46-53
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    • 1997
  • The TMA gas sensors are fabricated with the ZnO-based thin films grown by a RF magnetron sputtering method. The hall effect measurement and AES analysis are carried out to investigate the effects of the sputtering gases and dopants which effect on the electrical resistivity and sensitivity to TMA gas. We measure the cfhanges of the surface carrier concentration, haall electron mobility, electrical resistivity, surface condition, and depth profile of the films. The ZnO-based thin film sensors sputtered in oxygen, or added with dopants showed a high sruface carrier concentration, film sensors sputtered in oxygen and doped with 4.0 wt.% $Al_{2}$O$_{3}$, 1.0 wt.% TiO$_{2}$, and 0.2 wt% v$_{2}$O$_{5}$ showed the highest surface carrier concentration of 5.952 * 10$^{20}$ cm$^{-3}$ , hall electron mobility of 176.7 cm$^{2}$/V.s, lowest electrical resistivity of 6*10$^{-5}$ .ohm.cm and highest sensitivity of 12. These results were measured at a working temperature of 300.deg. C to 8 ppm TMA gas.

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Fabrication and characterization of Indium-Tin Oxide thin film on the commercial glass substrate (일반 현미경용 유리에 증착시킨 Indium-Tin Oxide 박막의 제작 및 특성)

  • 김여중;조길호
    • Journal of the Korean Vacuum Society
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    • v.9 no.1
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    • pp.30-35
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    • 2000
  • Indium-Tin Oxide (ITO) thin films were deposited on the commercial glass substrate by rf-magnetron sputtering. The ITO films with the thickness of 2,000~2,400 $\AA$ were prepared by changing the oxygen partial pressures of 2, 3, and 5%, as well as by changing the substrate temperature of $300^{\circ}C$ and $500^{\circ}C$. spectrophotometer, XRD, SEM, AFM, 4-point probe and Hall effect system were employed to characterize the ITO films. The optimum deposition conditions were the substrate temperature of $500^{\circ}C$ and oxygen partial pressure of 2-3%. At theses conditions, the ITO film showed the transmittance of 91%, the resistivity of $5.4\times10^{-3}\Omega$cm, the carrier concentration of $1.0\times10^{19}\textrm{cm}^{-3}$, and the carrier mobility of 150$\textrm{cm}^2$/Vsec. In XRD spectra, the (222) and (400) $In_2O_3$ planes were dominant under the optimum deposition conditions When the substrate was cleaned only by the method of ultrasonic cleaning without both pre-annealing and chemical treatment of the substrate, the ITO film exhibited the transmittance of 86%, the carrier concentration of $5.4\times10^{19}\textrm{cm}^{-3}$ and the mobility of 24$\textrm{cm}^2$/Vsec.

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Abnormal behaviors in electrical conductions of SOI substrate by thermal annealing temperature (열처리에 따른 SOI 기판에서의 전기전도특성의 이상 거동)

  • Cho, Won-Ju
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.126-127
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    • 2008
  • The effects annealing conditions on the electrical conductions of SOI substrate were studied. The reversible change of resistance and carrier concentration in accordance with the annealing temperature were observed for the first time in SOI substrate. The thermal donors due to interstitial oxygen atoms contribute the change of resistance and carrier concentration. Final1y, we show that the furnace annelaing at $500^{\circ}C$ at final heat treatment stage is effective for eliminate the thermal donor effects in SOI substrate.

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A Study on Properties of RF-sputtered Al-doped ZnO Thin Films Prepared with Different Ar Gas Flow Rates

  • Han, Seung Ik;Kim, Hong Bae
    • Applied Science and Convergence Technology
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    • v.25 no.6
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    • pp.145-148
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    • 2016
  • This paper, Al-doped ZnO(AZO) thin films for application as transparent conducting oxide films were deposited on the Corning glass substrate by using RF magnetron sputtering system. The effects of various Argon gas flow rates on optical and electrical characteristics of AZO films were investigate sputtering method. The Carrier Concentration is enhanced as Ar gas rate increases, and also the oxygen vacancy concentration. The figure of merit obtained in this study means that AZO films which deposited Ar gas rate of 75 sccm have the highest Carrier concentration and Hall mobility, which have the highest photoelectrical performance that it could be used as transparent electrodes.