• Title/Summary/Keyword: NiO thin film

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Effects of Oxygen Flow Ratio on the Crystallographic Orientation of NiO Thin Films Deposited by RE Magnetron Sputtering (RF 마그네트론 스퍼터링에 의한 NiO 박막 증착시 산소 유량비가 박막의 결정 배향성에 미치는 영향)

  • 류현욱;최광표;노효섭;박용주;박진성
    • Journal of the Korean Ceramic Society
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    • v.41 no.2
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    • pp.106-110
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    • 2004
  • Nickel oxide (NiO) thin films were prepared on Si(100) substrates at room temperature by RF magnetron sputtering using a NiO target. The effects of oxygen flow ratio for the plasma gas on the preferred orientation and surface morphology of the NiO films were investigated. Highly crystalline NiO film with (100) orientation was obtained when it was deposited in pure Ar gas. For NiO film deposited in pure O$_2$ gas, on the other hand, the orientation of the film changed from (100) to (111) and its deposition rate decreased. The origin of the preferred orientation of the films was discussed. NiO films also showed different surface morphologies and roughnesses with the oxygen flow ratio.

ZnNiO thin films deposited by r.f. magnetron sputtering method (RF Magnetron Sputtering법으로 증착된 ZnNiO박막의 특성)

  • 오형택;이태경;김동우;박용주;박일우;김은규
    • Journal of the Korean Vacuum Society
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    • v.12 no.4
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    • pp.269-274
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    • 2003
  • The electrical, optical and structural properties of ZnNiO thin _ films deposited on Si substrates using rf-magnetron sputtering method have been investigated before and after the thermal annealing processes. The crystallinity of the ZnNiO thin film become degraded with increasing the Ni contents. This is mainly because the lattice of the thin film was expanded due to the oxygen-deficient conditions. Concerning the electrical properties of the thin film, the carrier concentration increases ($6.81\times10^{14}\textrm{cm}^{-2}$) and Hall mobility decreases (36.3 $\textrm{cm}^2$/Vㆍs) with higher doping concentration of Ni. However, the carrier concentration and Hall mobility became low ($1.10\times10^{14}\textrm{cm}^2$ and high (209.6 $\textrm{cm}^2$/Vㆍs), respectively, after the thermal annealing process at $1000 ^{\circ}C$. We also observed a strong luminescene center peaking at 546 nm in photoluminescence spectra, which was caused by a deep level center in the ZnO band gap with oxygen deficient ZnNiO structure.

Effects of Ru Co-Sputtering on the Properties of Porous Ni Thin Films

  • Kim, Woo-Sik;Choi, Sun-Hee;Lee, Hae-Weon;Kim, Joo-Sun
    • Journal of the Korean Ceramic Society
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    • v.43 no.11 s.294
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    • pp.746-750
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    • 2006
  • NiO films and Ru co-sputtered NiO films were deposited by reactive magnetron sputtering for micro-solid oxide fuel cell anode applications. The deposited films were reduced to form porous films. The reduction kinetics of the Ru doped NiO film was more sluggish than that of the NiO film, and the resulting microstructure of the former exhibited finer pore networks. The possibility of using the films for the anodes of single chamber micro-SOFCs was investigated using an air/fuel mixed environment. It was found that the abrupt increase in the resistance is suppressed in the Ru co-sputtered film, as compared to undoped film.

Electrical, Electronic Structure and Optical Properties of Undoped and Na-doped NiO Thin Films

  • Denny, Yus Rama;Lee, Kangil;Seo, Soonjoo;Oh, Suhk Kun;Kang, Hee Jae;Yang, Dong-Seok
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.193.1-193.1
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    • 2014
  • This study was to investigate the electronic structure and optical properties of Na doped into NiO thin film using XPS and REELS. The films were grown by electron beam evaporation with varying the annealing temperature. The relationship between the electrical characteristics with the local structure of NiO thin films was also discussed. The x-ray photoelectron results showed that the Ni 2p spectra for all films consist of Ni 2p3/2 which indicate the presence of Ni-O bond from NiO phase and for the annealed film at temperature above $200^{\circ}C$ shows the coexist Ni oxide and Ni metal phase. The reflection electron energy loss spectroscopy spectra showed that the band gaps of the NiO thin films were slightly decreased with Na-doped into films. The Na-doped NiO showed relatively low resistivity compared to the undoped NiO thin films. In addition, the Na-doped NiO thin films deposited at room temperature showed the best properties, such as a p-type semiconducting with low electrical resistivity of $11.57{\Omega}.cm$ and high optical transmittance of ~80% in the visible light region. These results indicate that the Na doping followed by annealing process plays a crucial in enhancing the electrical and optical properties of NiO thin films. We believe that our results can be a good guide for those growing NiO thin films with the purpose of device applications, which require deposited at room temperature.

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Colossal Resistivity Change of Polycrystalline NiO Thin Film Deposited by RF Magnetron Sputtering (RF 마그네트론 스퍼터 방법에 의한 다결정 NiO 박막의 비저항 변화)

  • Kim, Youmg-Eun;No, Young-Soo;Park, Dong-Hee;Choi, Ji-Won;Chae, Keun-Hwa;Kim, Tae-Hwan;Choi, Won-Kook
    • Journal of the Korean Vacuum Society
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    • v.19 no.6
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    • pp.475-482
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    • 2010
  • Polycrystalline NiO thin films were deposited on glass substrate by RF magnetron sputtering using only Ar as a plasma sputter gas. based on the analysis of x-ray diffraction (XRD), NiO films had a polycrystalline cubic (NaCl type) structure. NiO thin films grown below and above $200^{\circ}C$ showed preferred orientation of (111) and (220) respectively. It showed colossal change in electrical resistivity as much a ${\sim}10^7$ order form an insulating state of $105\;{\Omega}cm$ below $200^{\circ}C$ to a conducting state of $10^{-2}{\sim}10^{-1}\;{\Omega}cm$ above $300^{\circ}C$ such a Mott metal-insulator transition (MIT) in polycrystalline.

Electrochemical Properties of NiO-YSZ Thin Films on 316 Stainless Steel Bipolar Plates Under a Simulated PEMFC Environment

  • Lee, W.G.;Jang, H.
    • Bulletin of the Korean Chemical Society
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    • v.33 no.4
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    • pp.1177-1182
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    • 2012
  • The corrosion resistance of 316L stainless steel coated with NiO-YSZ (Ni added yttria stabilized zirconia) was examined in a proton exchange membrane fuel cell (PEMFC) environment. The NiO-YSZ coating was carried out using a sol-gel dip coating method, and the corrosion resistance and interfacial contact resistance (ICR) were determined by the composition and morphology of the NiO-YSZ film. The corrosion resistance increased with increasing Ni content in the NiO-YSZ film, but rapid corrosion was observed when the YSZ film contained more than 15 wt % Ni due to surface cracks. The polarization resistance was improved by several orders of magnitude when 316L stainless steel was coated with a 15 wt % NiO-YSZ film compared to bare 316L. The ICR of the NiO-YSZ film was decreased to that of bare 316L when the YSZ film contained 25 wt % NiO, suggesting the possible application of NiO-YSZ coated stainless steel for a bipolar plate.

Gradational Double Annealing Process for Improvement of Thermal Characteristics of NiCr Thin Films (NiCr 박막의 발열 특성 개선을 위한 순차적 이중 열처리 방법 연구)

  • Kwon, Yong;Noh, Whyo-Sup;Kim, Nam-Hoon;Cho, Dong-You;Park, Jinseong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.8
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    • pp.714-719
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    • 2005
  • NiCr thin film was deposited by DC magnetron sputtering on $A;_2O_3$/Si substrate with NiCr (80:20) alloy target. NiCr thin films were annealed at $300^{\circ}C,\;400^{\circ}C,\;500^{\circ}C,\;600^{\circ}C,\;and\;700^{\circ}C$ for 6 hr in $H_2$ after annealing at $500^{\circ}C$ for 6hr in air atmosphere, respectively. To analyze NiCr thin film properties, the changes of its micro structure were Investigated through field emission scanning electron microscope (FESEM). X-ray photoelectron spectroscopy (XPS) was used to analyze a surface of NiCr thin film. Resistance of NiCr thin film was measured by 4-point probe technique. The generated heats were measured by infrared thermometer through the application of DC voltage (5 V/l2 V). NiCr thin film treated by gradational double annealing process had uniform and small grains. Maximum temperature generated heat by NiCr micro heater was $173^{\circ}C$. We expect that our results will be a useful reference in the realization of NiCr micro heater.

Fabrication and Characterization of Ni-Cr Alloy Thin Films for Application to Precision Thin Film Resistors

  • Lee, Boong-Joo;Shin, Paik-Kyun
    • Journal of Electrical Engineering and Technology
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    • v.2 no.4
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    • pp.525-531
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    • 2007
  • Ni(75 wt.%)-Cr(20 wt.%)-Al(3 wt.%)-Mn(4 wt.%)-Si(1 wt.%) alloy thin films were prepared using the DC magnetron sputtering process by varying the sputtering conditions such as power, pressure, substrate temperature, and post-deposition annealing temperature in order to fabricate a precision thin film resistor. For all the thin film resistors, sheet resistance, temperature coefficient of resistance (TCR), and crystallinity were analyzed and the effects of sputtering conditions on their properties were also investigated. The oxygen content and TCR of Ni-Cr-Al-Mn-Si resistors were decreased by increasing the sputtering pressure. Their sheet resistance, TCR, and crystallinity were enhanced by elevating the substrate temperature. In addition, the annealing of the resistor thin films in air at a temperature higher than $300^{\circ}C$ lead to a remarkable rise in their sheet resistance and TCR. This may be attributed to the improved formation of NiO layer on the surface of the resistor thin film at an elevated temperature.

Effect of the Buffered-template on the Property of YBCO Superconducting Film Deposited by MOCVD Method (MOCVD 법에 의해 제조된 YBCO 초전도 박막의 물성에 대한 완충층 템플릿의 영향)

  • Jun, Byung-Hyuk;Choi, Jun-Kyu;Kim, Chan-Joong
    • Progress in Superconductivity
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    • v.8 no.1
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    • pp.27-32
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    • 2006
  • [$YBa_2Cu_3O_{7-x}$] thin films were deposited on various buffered-templates by a metal organic chemical vapor deposition(MOCVD). Three different templates of $CeO_2/YSZ/CeO_2/pure-Ni(CYC),\;CeO_2/YSZ/Y_2O_3/Ni-3at.%W(YYC)$ and $CeO_2/IBAD-YSZ$/stainless steel were used. The Ni and Ni-W alloy tapes were biaxially textured by cold rolling and annealing heat treatment. The dense YBCO films were grown on both the IBAD and YYC templates with no microcrack, while the YBCO films on the CYC templates were grown with the formation of microcracks and NiO. The YBCO film on the YYC template showed the higher $I_c$ than that on CYC template. Especially, the IBAD templates with a thin $CeO_2$(type I) and thick $CeO_2$(type II) top layer were used to compare the deposition nature of the YBCO on them. Comparing the current property of the YBCO films on IBAD templates, the YBCO film deposited on thick $CeO_2$ layer was better than the film on thin $CeO_2$ layer.

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Micro Structure and Surface Characteristics of NiCr Thin films Prepared by DC Magnetron Sputter according to Annealing Conditions (DC 마그네트론 스퍼터링 NiCr 박막의 열처리 조건에 따른 미세구조 및 표면특성)

  • Kwon, Yong;Kim, Nam-Hoon;Choi, Dong-You;Lee, Woo-Sun;Seo, Yong-Jin;Park, Jin-Seong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.6
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    • pp.554-559
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    • 2005
  • Ni/Cr thin film is very interesting material as thin film resistors, filaments, and humidity sensors because their relatively large resistivity, more resistant to oxidation and a low temperature coefficient of resistance (TCR). These interesting properties of Ni/Cr thin films are dependent upon the preparation conditions including the deposition environment and subsequent annealing treatments. Ni/Cr thin films of 250 nm were deposited by DC magnetron sputtering on $Al_2O_3/Si$ substrate with 2-inch Ni/Cr (80/20) alloy target at room temperature for 45 minutes. Annealing treatments were performed at $400^{\circ}C,\;500^{\circ}C,\;and\;600^{\circ}C$ for 6 hours in air or $H_2$ ambient, respectively. The clear crystal boundaries without crystal growth and the densification were accomplished when the pores were disappeared in air ambient. Most of surface was oxidic including NiO, $Ni_2O_3$ and $Cr_xO_y$(x=1,2, y=2,3) after annealing in air ambient. The crystal growth in $H_2$ ambient was formed and stabilized by combination with each other due to the suppression of oxidized substance on film surface. Most oxidic Ni was restored when the oxidic Cr was present due to its stability in high-temperature $H_2$ ambient.