• Title/Summary/Keyword: Porous thin film

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Effects of Sputtering pressure on preferred Orientation of Shielding NbTi Thin Film by RF Magnetron Sputtering (RF 마그네트론 스퍼터링법으로 제조된 차폐용 NbTi박막의 우선방향에 미치는 스퍼터링 압력의 영향)

  • Kim, Bong-Seo;Woo, Byung-Chul;Byun, Woo-Bong;Lee, Hee-Woong
    • Proceedings of the KIEE Conference
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    • 1995.07c
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    • pp.1098-1101
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    • 1995
  • NbTi thin films were prepared on Si wafer and Cu substrate by rf magnetron sputtering in the range of sputtering pressure $3{\times}10^{-2}$torr to $3{\times}10^{-4}$torr at room temperature. The influence of sputtering pressure and substrate type on crystallographic orientation and morphology of NbTi thin films was investigated by using X-ray diffraction(XRD) and scanning electron microscopy(SEM), respectively. And the effect of crystallographic orientation and morphology of NbTi film on electromagnetic behaviors was estimated by measuring critical current in various applied magnetic field. The film morphology changed from porous structure consisting of tapered crystallites to densely deposited film decreasing with sputtering pressure. The change of crystallographic orientation with the sputtering pressure and rf power was calculated from the texture coefficient of(002) plane based on XRD patterns. It was found that a change of texture coefficient of(002) plane increased with decreasing sputtering pressure. From observation of critical current in various applied magnetic field, we have identified that the change of critical current abruptly decrease applying with magnetic field and NbTi film produced at high sputtering pressure does not exhibit superconductivity but at low sputtering pressure shows superconductivity.

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Fabrication of Micro Solid Oxide Fuel Cell by Thin Film Processing Hybridization: I. Multilayer Structure of Sputtered YSZ Thin Film Electrolyte and Ni-Based Anodes deposited by Spray Pyrolysis (박막공정의 융합화를 통한 초소형 고체산화물 연료전지의 제작: I. Spray Pyrolysis법으로 증착된 Ni 기반 음극과 스퍼터링으로 증착된 YSZ 전해질의 다층구조)

  • Son, Ji-Won;Kim, Hyoung-Chul;Kim, Hae-Ryoung;Lee, Jong-Ho;Lee, Hae-Weon;Bieberle-Hutter, A.;Rupp, J.L.M.;Muecke, U.P.;Beckel, D.;Gauckler, L.J.
    • Journal of the Korean Ceramic Society
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    • v.44 no.10
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    • pp.589-595
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    • 2007
  • Physical properties of sputtered YSZ thin film electrolytes on anode thin film by spray pyrolisis has been investigated to realize the porous electrode and dense electrolyte multilayer structure for micro solid oxide fuel cells. It is shown that for better crystallinity and density, YSZ need to be deposited at an elevated temperature. However, if pure NiO anode was used for high temperature deposition, massive defects such as spalling and delamination were induced due to high thermal expansion mismatch. By changing anode to NiOCGO composite, defects were significantly reduced even at high deposition temperature. Further research on realization of full cells by processing hybridization and cell performance characterization will be performed in near future.

Preparation of Electrolyte Thin Film for Anode Support Type Solid Oxide Fuel Cells by Electrophoretic Deposition and Dip-Coating (전착법과 담금법에 의한 음극지지형 SOFC 지르코니아 전해질막 제조)

  • 김상우;이병호;손용배;송휴섭
    • Journal of the Korean Ceramic Society
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    • v.36 no.8
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    • pp.791-798
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    • 1999
  • The preparation method of yttria-stabilized zirconia(YSZ) thin film for an anode support type solid oxide fuel cell(SOFC) by electrophoretic deposition(EPD) and dip-coating was studied. And the difference in both preparation method was investigated through basic understanding of processing parameters which may significantly affect weight microstruxcture and defect of film. In dip-coating the thickness of film increased with time until 30 s and then the weight of film decreased with time due to particle falling off from the coagulated film. In EPD although the weight of film increased with time and applied constant-current sagging of the film was observed when the applied current was less that 0.035 mA/$cm^2$ and more than 120 s. Since YSZ thin film by EPD on porous substrate was dense smooth and homogeneous it was expected to be suitable for the electrolyte of an anode support type SOFC.

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Fabrication Of Thin Electrolyte Layer For Solid Oxide Fuel Cell by Vacuum Slurry Dip-coating Process (진공 슬러리 담금 코팅 공정에 의한 고체 산화물 연료전지용 박막 전해질막 제조에 관한 연구)

  • Son, Hui-Jeong;Lim, Tak-Hyoung;Lee, Seung-Bok;Shin, Dong-Tyul;Song, Rak-Hyun;Kim, Sung-Hyun
    • Transactions of the Korean hydrogen and new energy society
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    • v.17 no.2
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    • pp.204-211
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    • 2006
  • The electrolyte in the solid oxide fuel cell must be dense enough to avoid gas leakage and thin enough to reduce the ohmic resistance. In order to manufacture the thin and dense electrolyte layer, 8 mol% $Y_2O_3$ stabilized-$ZrO_2$ (8YSZ) electrolyte layers were coated on the porous tubular substrate by the novel vacuum slurry dip-coating process. The effects of the slurry concentration, presintering temperature, and vacuum pressure on the thickness and the gas permeability of the coated electrolyte layers have been examined in the vacuum slurry coating process. The vacuum-coated electrolyte layers showed very low gas permeabilities and had thin thicknesses. The single cell with the vacuum-coated electrolyte layer indicated a good performance of $495\;mW/cm^2$, 0.7 V at $700^{\circ}C$. The experimental results show that the vacuum dip-coating process is an effective method to fabricate dense thin film on the porous tubular substrate.

Effect of surface modifiers on the nano porous silica aerogels prepared by ambient drying process (상압건조 나노다공성 실리카 에어로젤에 대한 개질제 효과)

  • Kim, Tae-Jung;Oh, Young-Jei
    • Journal of Sensor Science and Technology
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    • v.16 no.1
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    • pp.77-83
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    • 2007
  • Nanoporous silica aerogels with various surface modifiers were prepared by ambient drying process. Tetraethylorthosilicate (TEOS) were used a raw material. Ambient drying process for various surface modifier was studied in the point of view of a crack-free monolith and thin films and low cost. Various kinds of surface modifiers like as hexamethyldisilazane (HMDSZ), trimethlychlorosilane (TMCS), methlytriethoxylsilane (MTES), and methlytrimethoxysilane (MTMS) were studied in order to enhance hydrophobicity for the silica aerogel. Surface modified aerogels were evaluated by FT-IR, TG, BET, SEM and wetting angle measurement. Homogeneous and crack-free aerogels were obtained by modifying the HMDSZ and the TMCS. However silica xerogel was obtained when modified with MTMS, MTES.

Characteristics of ZnO Films Deposited on Poly 3C-SiC Buffer Layer by Sol-Gel Method

  • Phan, Duy-Thach;Chung, Gwiy-Sang
    • Transactions on Electrical and Electronic Materials
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    • v.12 no.3
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    • pp.102-105
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    • 2011
  • This work describes the characteristics of zinc oxide (ZnO) thin films formed on a polycrystalline (poly) 3C-SiC buffer layer using a sol-gel process. The deposited ZnO films were characterized using X-ray diffraction, scanning electron microscopy, and photoluminescence (PL) spectra. ZnO thin films grown on the poly 3C-SiC buffer layer had a nanoparticle structure and porous film. The effects of post-annealing on ZnO film were also studied. The PL spectra at room temperature confirmed the crystal quality and optical properties of ZnO thin films formed on the 3C-SiC buffer layer were improved due to close lattice mismatch in the ZnO/3C-SiC interface.

Preparation of Disulfonated Poly(arylene ether sulfone) Random Copolymer Thin Film Composite Membranes Using a Benign Solvent (친환경용매 기반의 술폰화 폴리아릴렌 에테르 술폰 랜덤 공중합체 Thin Film Composite 제조)

  • Lee, Chang Hyun;McGrath, James E.;Freeman, Benny
    • Membrane Journal
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    • v.24 no.4
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    • pp.292-300
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    • 2014
  • Chlorine-resistant sulfonated poly(arylene ether sulfone) random copolymer (SPAES)-thin film composite (TFC) membranes for desalination are prepared using monoglyme as a selective solvent, which dissolves SPAES, but should be inert to porous polysulfone layer (e.g., Udel$^{(R)}$). Different from formic acid and diethylene glycol used as other selective solvents, monoglyme is environmentally friendly and has much lower boiling temperature. After a pretreatment of Udel$^{(R)}$ support film in isopropyl alcohol-glycerine mixture to minimize pore penetration leading to fairly reduced water flux, coating of SPAES solution in monoglyme onto the support and stepwise drying processes are conducted for defect-free TFC formation. The transport behavior through SPAES-TFC membranes is observed, correlating with the effects of sulfonation level, protonation, and physical and chemical crosslinking of SPAES selective layers.

Capacitance Properties of Nano-Structure Controlled Alumina on Polymer Substrate (폴리머 기판위에 형성된 나노구조제어 알루미나의 캐패시터 특성)

  • Jung, Seung-Won;Min, Hyung-Sub;Han, Jeong-Whan;Lee, Jeon-Kook
    • Korean Journal of Materials Research
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    • v.17 no.2
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    • pp.81-85
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    • 2007
  • Embedded capacitor technology can improve electrical perfomance and reduce assembly cost compared with traditional discrete capacitor technology. To improve the capacitance density of the $Al_2O_3$ based embedded capacitor on Cu cladded fiber reinforced plastics (FR-4), the specific surface area of the $Al_2O_3$ thin films was enlarged and their surface morphologies were controlled by anodization process parameters. From I-V characteristics, it was found that breakdown voltage and leakage current were 23 V and $1{\times}10^{-6}A/cm^2$ at 3.3 V, respectively. We have also measured C-V characteristics of $Pt/Al_2O_3/Al/Ti$ structure on CU/FR4. The capacitance density was $300nF/cm^2$ and the dielectric loss was 0.04. This nano-porous $Al_2O_3$ is a good material candidate for the embedded capacitor application for electronic products.

Fabrication of Single Layer Anti-reflection Thin Film by Sol-gel Method (Sol-gel법에 의한 단층 반사 방지막 제조)

  • Park, Jong-Guk;Jeon, Dae-Woo;Lee, Mi-Jai;Lim, Tea-Young;Hwang, Jonghee;Bae, Dong-Sik;Kim, Jin-Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.28 no.12
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    • pp.821-825
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    • 2015
  • Anti-reflective (AR) thin film was fabricated on a glass substrate by sol-gel method. The coating solution was synthesized with TEOS (tetraethlyorthosilicate) and poly ethylene glycol (PEG, 4.0 wt%). As the withdrawal speed of coating was changed from 0.1 mm/sec to 0.3 mm/sec, the thickness and refractive index of prepared thin films were changed. The reflectance and transmittance of coating glass fabricated by the withdrawal speed of 0.1 mm/sec were 0.62% and 95.0% in visible light range. The refractive index and thickness of single layer thin film were n= 1.29 and ca. 99.0 nm.