• Title/Summary/Keyword: Morphology of oxide film

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Dependence of Gas Pressure on Cr Oxide Thin Film Growth Using a Plasma Focus Device (플라즈마 포커스를 이용한 크롬 산화물 박막 성장의 분위기 기체 압력 의존성 연구)

  • Jung, Kyoo-Ho;Lee, Jae-Kap;Im, Hyun-Sik;Karpinski, L.;Scholz, M.;Lee, Jeon-Kook
    • Korean Journal of Materials Research
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    • v.17 no.6
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    • pp.308-312
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    • 2007
  • Chromium oxide thin films have been deposited on silicon substrates using a tabletop 9kJ mathertyped plasma focus (PF) device. Before deposition, pinch behavior with gas pressure was observed. Strength of pinches was increased with increasing working pressure. Deposition was performed at room temperature as a function of working pressure between 50 and 1000 mTorr. Composition and surface morphology of the films were analyzed by Auger Electron Spectroscopy and Scanning Electron Microscope, respectively. Growth rates of the films were decreased with pressure. The oxide films were polycrystalline containing some impurities, Cu, Fe, C and revealed finer grain structure at lower pressure.

Multi-film coated bipolar plates for PEMFC (Proton Exchange Membrane Fuel Cell) application (다층박막 코팅된 PEMFC (Proton Exchange Membrane Fuel Cell)용 바이폴라 플레이트)

  • Jeon, Gwang-Yeon;Yun, Young-Hoon;Cha, In-Su
    • Proceedings of the KIPE Conference
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    • 2008.06a
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    • pp.646-648
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    • 2008
  • The multi-films of a metallic film and a transparent conducting oxide (TCO, indium-tin oxide, ITO) film were formed on the stainless steel 316 and 304 plates by a sputtering method and an E-beam method and then the external metallic region of the stainless steel bipolar plates was converted into the metal nitride films through an annealing process. The multi-film formed on the stainless steel bipolar plates showed the XRD patterns of the typical indium-tin oxide, the metallic phase and the metal substrate and the external nitride film. The XRD pattern of the thin film on the bipolar plates modified showed two metal nitride phases of CrN and $Cr_2N$ compound. Surface microstructural morphology of the multi-film deposited bipolar plates was observed by AFM and FE-SEM. The electrical resistivity of the stainless steel bipolar plates modified was evaluated.

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A novel approach to bind graphene oxide to polyamide for making high performance Reverse Osmosis membrane

  • Raval, Hiren D.;Das, Ravi Kiran
    • Membrane and Water Treatment
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    • v.8 no.6
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    • pp.613-623
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    • 2017
  • We report the novel thin film composite RO membrane modified by graphene oxide. The thin film composite RO membrane was exposed to 2000 mg/l sodium hypochloride; thereafter it was subjected to different graphene oxide concentration ranging from 50 mg/l to 1000 mg/l in water. The resultant membrane was crosslinked with 5000 mg/l N-hydroxysuccinimide. The performance of different membranes were analysed by solute rejection and water-flux measurement. It was found that 100 mg/l graphene oxide exposure followed by 5000 mg/l N-hydroxysuccinimide treatment resulted in the membrane with the highest solute rejection of 97.78% and water-flux of 4.64 Liter per sqm per hour per bar g. The membranes were characterized by contact angle for hydrophilicity, scanning electron micrographs for surface morphology, energy dispersive X-Ray for chemical composition of the surface, Atomic force microscope for surface roughness, ATR-FTIR for chemical structure identification. It was found that the graphene oxide modified membrane increases the salt rejection performance after exposure to high-fouling water containing albumin. Highly hydrophilic, antifouling surface formation with the nanomaterial led to the improved membrane performance. Moreover, the protocol of incorporating nanomaterial by this post-treatment is simple and can be applied to any RO membrane after it is manufactured.

Enhanced Electrochromic Performance by Uniform Surface Morphology of Tungsten Oxide Films (텅스텐산화물 막의 균일한 표면 형상에 의한 향상된 전기변색 성능)

  • Kim, Kue-Ho;Koo, Bon-Ryul;Ahn, Hyo-Jin
    • Korean Journal of Materials Research
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    • v.28 no.7
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    • pp.411-416
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    • 2018
  • Tungsten oxide($WO_3$) films with uniform surface morphology are fabricated using a spin-coating method for applications of electrochromic(EC) devices. To improve the EC performances of the $WO_3$ films, we control the heating rate of the annealing process to 10, 5, and $1^{\circ}C/min$. Compared to the other samples, the $WO_3$ films fabricated at a heating rate of $5^{\circ}C/min$ shows superior EC performances for transmittance modulation(49.5 %), response speeds(8.3 s in a colored state and 11.2 s in a bleached state), and coloration efficiency($37.3cm^2/C$). This performance improvement is mainly related to formation of a uniform surface morphology with increased particle size without any cracks by an optimized annealing heating rate, which improves the electrical conductivity and electrochemical activity of the $WO_3$ films. Thus, the $WO_3$ films with a uniform surface morphology prepared by the optimized annealing heating rate can be used as a potential candidate for performance improvement of the EC devices.

Nickel Oxide Nano-Flake Films Synthesized by Chemical Bath Deposition for Electrochemical Capacitors (CBD(Chemical Bath Deposition) 법으로 제조된 전기화학식 캐패시터용 NiO 나노박편 필름)

  • Kim, Young-Ha;Park, Soo-Jin
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.163.2-163.2
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    • 2010
  • In this work, nano-flake shaped nickel oxide (NiO) films were synthesized by chemical bath deposition technique for electrochemical capacitors. The deposition was carried out for 1 and 2 h at room temperature using nickel foam as the substrate and the current collector. The structure and morphology of prepared NiO film were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). And, electrochemical properties were characterized by cyclic voltammetry, galvanostatic charge-discharge, and AC impedence measurement. It was found that the NiO film was constructed by many interconnected NiO nano-flakes which arranged vertically to the substrate, forming a net-like structure with large pores. The open macropores may facilitate the electrolyte penetration and ion migration, resulted in the utilization of nickel oxide due to the increased surface area for electrochemical reactions. Furthermore, it was found that the deposition onto nickel foam as substrate and curent collector led to decrease of the ion transfer resistance so that its specific capacitance of a NiO film had high value than NiO nano flake powder.

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A Study on CMP Properties of SnO2 Thin Film for Application of Gas Sensor (가스센서 적용을 위한 SnO2 박막의 CMP 특성 연구)

  • Lee, Woo-Sun;Choi, Gwon-Woo;Kim, Nam-Hoon;Park, Jin-Seong;Seo, Yong-Jin
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.12
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    • pp.1296-1300
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    • 2004
  • SnO$_2$ is one of the most suitable gas sensor materials. The microstructure and surface morphology of films must be controlled because the electrical and optical properties of SnO$_2$ films depend on these characteristics. The effects of chemical mechanical polishing(CMP) on the variation of morphology of SnO$_2$ films prepared by RF sputtering system were investigated. The commercially developed ceria-based oxide slurry, silica-based oxide slurry, and alumina-based tungsten slurry were used as CMP slurry. Non-uniformities of all slurries met stability standards of less than 5 %. Silica slurry had the highest removal rate among three different slurries, sufficient thin film topographies and suitable root mean square(RMS) values.

Fabrication and Characterization of Lead Oxide (PbO) Film for High Efficiency X-ray Detector (고효율 X선 검출기 적용을 위한 PbO 필름 제작 및 특성 연구)

  • Cho, Sung-Ho;Kang, Sang-Sik;Choi, Chi-Won;Kwun, Chul;Nam, Sang-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.329-329
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    • 2007
  • Photoconductive poly crystalline lead oxide coated on amorphous thin film transistor (TFT) arrays is the best candidate for direct digital x-ray detector for medical imaging. Thicker films with lessening density often show lower x-ray induced charge generation and collection becomes less efficient. In this work, we present a new methodology used for the high density deposition of PbO. We investigate the structural properties of the films using X-ray diffraction and electron microscopy experiments. The film coatings of approximately $200\;{\mu}m$ thickness were deposited on $2"{\times}2"$ conductive-coated glass substrates for measurements of dark current and x-ray sensitivity. The lead oxide (PbO) films of $200\;{\mu}m$ thickness were deposited on glass substrates using a wet coating process in room temperature. The influence of post-deposition annealing on the characteristics of the lead oxide films was investigated in detail. X-ray diffraction and scanning electron microscopy, and atomic force microscopy have been employed to obtain information on the morphology and crystallization of the films. Also we measured dark current, x-ray sensitivity and linearity for investigation of the electrical characteristics of films. It was found that the annealing conditions strongly affect the electrical properties of the films. The x-ray induced output charges of films annealed in oxygen gas increases dramatically with increasing annealing temperatures up to $500^{\circ}C$ but then drops for higher temperature anneals. Consequently, the more we increase the annealing temperatures, the better density and film quality of the lead oxide. Analysis of this data suggests that incorporation and decomposition reactions of oxygen can be controlled to change the detection properties of the lead oxide film significantly. Post-deposition thermal annealing is also used for densely film. The PbO films that are grown by new methodology exhibit good morphology of high density structure and provide less than $10\;pA/mm^2$ dark currents as they show saturation in gain (at approximate fields of $4\;V/{\mu}m$). The ability to operate at low voltage gives adequate dark currents for most applications and allows voltage electronics designs.

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Chemical Degradation of Tungsten Oxide Thin Films (텅스텐 산화물 박막의 화학적 퇴화)

  • Lee, Kil-Dong
    • Solar Energy
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    • v.15 no.3
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    • pp.141-149
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    • 1995
  • The tungsten oxide thin films were prepared on $s_i$ wafer by using an electron-beam evaporation technique. Thickness and structure of tungsten oxide film degraded in various electrolytes were analyzed by Rutherford backscattering spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscope. Thickness of $WO_3$ film was the most dissolved in 1M $H_2SO_4$ electrolytye. We have confirmed that the degradation of this films was accelerated by $H_2O$ in electrolytes. But the electronic structure of film degraded by electrolyte contained of glycerol was not changed as comparision with as-deposited film. The degradation may be attributed to a change of thickness and the surface morphology of the film.

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The Effect of Hafnium Dioxide Nanofilm on the Organic Thin Film Transistor

  • Choi, Woon-Seop;Song, Young-Gi
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08b
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    • pp.1315-1318
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    • 2007
  • Hafnium dioxide nano film as gate insulator for organic thin film transistors is prepared by atomic layer deposition. Mostly crystalline of $HfO_2$ films can be obtained with oxygen plasma and with water at relatively low temperature of $150^{\circ}C$. $HfO_2$ was deposited as a uniform rate $1.2A^{\circ}/cycle$. The morphology and performances of OTFT will be discussed.

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Field emission from diamond-like carbon films studied by scanning anode

  • Ahn, S.H.;Jeon, D.;Lee, K.-R.
    • Journal of Korean Vacuum Science & Technology
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    • v.3 no.1
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    • pp.54-58
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    • 1999
  • We deposited diamond-like carbon (DLC) films using ion beam sputtering of a graphite target on flat substrates for use as a thin film field emitter. An n-type silicon wafer, titanium-coated silicon, and indium tin oxide (ITO) coated glass were used as a substrate. All films exhibited a sudden increase in the emission after a breakdown occurred at high voltage. The morphology of the films after the breakdown depended on the substrate. On ITO and Ti substrates, the DLC film peeled off upon breakdown, but on the Si substrate the surface melting due to breakdown resulted in the formation of various structures such as a sharp point, mound, and crater. By scanning the deformed surface with a tip anode, we found that the emission was concentrated at the deformed sites, indicating that the field enhancement due to the morphology change was responsible for the increased emission.

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