• Title/Summary/Keyword: Al2O3 Thin Film

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Enhancement of photoluminescence and electrical properties of Ga doped ZnO thin film grown on $\alpha$-$Al_2O_3$(0001) single crystal substrate by RE magnetron sputtering through rapid thermal annealing (RF 마그네트론 스퍼터링 법으로 사파이어 기판 위에 성장시킨 ZnO: Ga 박막의 RTA 처리에 따른 photoluminescence 특성변화)

  • Cho, Jung;Na, Jong-Bum;Oh, Min-Seok;Yoon, Ki-Hyun;Jung, Hyung-Jin;Choi, Won-Guk
    • Journal of the Korean Vacuum Society
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    • v.10 no.3
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    • pp.335-340
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    • 2001
  • $Ga_2O_3$(1 wt%)-doped ZnO(GZO) thin films were grown on ${\alpha}-Al_2O_3$ (0001) by rf magnetron sputtering at $510^{\circ}C$, whose crystal structure was polycrystalline. As-grown GZO thin film shows poor electrical properties and photoluminescence (PL) spectra. To improve these properties, GZO thin films were annealed at 800-$900^{\circ}C$ in $N_2$atmosphere for 3 min. After the rapid thermal annealing(RTA), deep defect-level emission disappears and near-band emission is greatly enhanced. Annealed GZO thin films show very low resisitivity of $2.6\times10^{-4}\Omega$/cm with $3.9\times10^{20}/\textrm{cm}^3$ carrier concentration and exceptionally high mobility of 60 $\textrm{cm}^2$/V.s. These improved physical properties are explained in terms of translation of doped-Ga atoms from interstitial to substitutional site.

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Study on the narrowed nanopores of anodized aluminum oxide template by thin-film deposition using e-beam evaporation (전자빔 증발법 박막 증착을 이용한 양극 산화 알루미늄 템플릿의 나노 포어 가공 연구)

  • Lee, Seung-Hun;Lee, Minyoung;Kim, Chunjoong;Kim, Kwanoh;Yoon, Jae Sung;Yoo, Yeong-Eun;Kim, Jeong Hwan
    • Journal of the Korean institute of surface engineering
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    • v.54 no.1
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    • pp.25-29
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    • 2021
  • The fabrication of nanopore membrane by deposition of Al2O3 film using electron-beam evaporation, which is fast, cost-effective, and negligible dependency on substance material, is investigated for potential applications in water purification and sensors. The decreased nanopore diameter owing to increased wall thickness is observed when Al2O3 film is deposited on anodic aluminum oxide membrane at higher deposition rate, although the evaporation process is generally known to induce a directional film deposition leading to the negligible change of pore diameter and wall thickness. This behavior can be attributed to the collision of evaporated Al2O3 particles by the decreased mean free path at higher deposition rate condition, resulting in the accumulation of Al2O3 materials on both the surface and the edge of the wall. The reduction of nanopore diameter by Al2O3 film deposition can be applied to the nanopore membrane fabrication with sub-100 nm pore diameter.

Implementation of High Carrier Mobility in Al-N Codoped p-Type ZnO Thin Films Fabricated by Direct Current Magnetron Sputtering with ZnO:Al2O3 Ceramic Target

  • Jin, Hujie;Xu, Bing;Park, Choon-Bae
    • Transactions on Electrical and Electronic Materials
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    • v.12 no.4
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    • pp.169-173
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    • 2011
  • In this study, Al-N codoped p-type zinc oxide (ZnO) thin films were deposited on Si and homo-buffer layer templates in a mixture of $N_2$ and $O_2$ gas with ceramic ZnO:(2 wt% $Al_2O_3$) as a sputtering target using DC- magnetron sputtering. X-ray diffraction spectra of two-theta diffraction showed that all films have a predominant (002) peak of ZnO Wurtzite structure. As the $N_2$ fraction in the mixed $N_2$ and $O_2$ gases increased, field emission secondary electron microscopy revealed that the surface appearance of codoped films on Si varied from smooth to textured structure. The p-type ZnO thin films showed carrier concentration in the range of $1.5{\times}10^{15}-2.93{\times}10^{17}\;cm^{-3}$, resistivity in the range of 131.2-2.864 ${\Omega}cm$, and mobility in the range of $3.99-31.6\;cm^2V^{-1}s^{-1}$ respectively.

Characterization of Al-Doped ZnO Thin Film Grown on Buffer Layer with RF Magnetron Sputtering Method (버퍼 층을 이용한 RF 마그네트론 스퍼터 방법에 의한 Al:ZnO 박막의 성장)

  • No, Young-Soo;Park, Dong-Hee;Kim, Tae-Whan;Choi, Ji-Won;Choi, Won-Kook
    • Journal of the Korean Vacuum Society
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    • v.18 no.3
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    • pp.213-220
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    • 2009
  • The optimal condition of low temperature deposition of transparent conductive Al-doped zinc oxide (AZO) films is studied by RF magnetron sputtering method. To achieve enhanced-electrical property and good crystallites quality, we tried to deposit on glass using a two-step growth process. This process was to deposit AZO buffer layer with optimal growth condition on glass in-situ state. The AZO film grown at rf 120 W on buffer layer prepared at RF $50{\sim}60\;W$ shows the electrical resistivity $3.9{\times}10^{-4}{\Omega}cm$, Carrier concentration $1.22{\times}10^{21}/cm^3$, and mobility $9.9\;cm^2/Vs$ in these results, The crystallinity of AZO film on buffer layer was similar to that of AZO film on glass with no buffer later but the electrical properties of the AZO film were 30% improved than that of the AZO film with no buffer layer. Therefore, the cause of enhanced electrical properties was explained to be dependent on degree of crystallization and on buffer layer's compressive stress by variation of $Ar^+$ ion impinging energy.

Photoluminescence Behaviors of the ZnGa2O4 Phosphor Thin Films on Al2O3 substrates as a Function of Oxygen Pressures (Al2O3 기판위에 증착한 ZnGa2O4 형광체 박막의 산소분압에 따른 형광특성)

  • Yi, Soung-Soo
    • Journal of Sensor Science and Technology
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    • v.11 no.2
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    • pp.118-123
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    • 2002
  • $ZnGa_2O_4$ thin film phosphors have been deposited using a pulsed laser deposition technique on $Al_2O_3$(0001) substrates at a substrate temperature of $550^{\circ}C$ with various oxygen pressures 100, 200 and 300 mTorr. The films grown under different growth oxygen pressures have been characterized using microstructural and luminescent measurements. The different photoluminescence (PL) characteristics with the increase in oxygen pressures may result from the change of the crystallinity and the composition ratio of Zn and Ga in the films. The luminescent spectra show a broad band extending from 300 to 600 nm peaking at 460 nm. The PL brightness data obtained from the $ZnGa_2O_4$ films grown under optimized conditions have indicated that the sapphire is a promising substrate for the growth of high quality $ZnGa_2O_4$ thin film phosphor.

OBSERVATION OF THE DOMAIN STRUCTURES IN SOFT MAGNETIC ${(Fe_{97}Al_3)}_{85}N_{15}/Al_2O_3$ MULTILAYERS

  • Stobiecki, T.;Zoladz, M.;Roell, K.;Maass, W.
    • Proceedings of the Korean Magnestics Society Conference
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    • 2002.12a
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    • pp.14-15
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    • 2002
  • Iron nitride alloy films prepared in the form of laminated ${(Fe_{97}Al_3)}_{85}N_{15}/Al_2O_3$ multilayers (Ml's) due to excellent soft magnetic properties and high saturation magnetization [1, 2] are very promising materials for poles and shields in ultra high density thin film heads. The present work concerns the ferromagnetic (FM) coupling effect as a function of the thickness of $Al_2O_3$ spacers by analysis of the magnetic domain structure.

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Substrate Bias Voltage Dependence of Electrical Properties for ZnO:Al Film by DC Magnetron Sputtering (Bias 전압에 따른 ZnO:Al 투명전도막의 전기적 특성)

  • 박강일;김병섭;임동건;이수호;곽동주
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.7
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    • pp.738-746
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    • 2004
  • Recently zinc oxide(ZnO) has emerged as one of the most promising transparent conducting films with a strong demand of low cost and high performance optoelectronic devices, ZnO film has many advantages such as high chemical and mechanical stabilities, and abundance in nature. In this paper, in order to obtain the excellent transparent conducting film with low resistivity and high optical transmittance for Plasma Display Pannel(PDP), aluminium doped zinc oxide films were deposited on Corning glass substrate by dc magnetron sputtering method. The effects of the discharge power and doping amounts of $Al_2$$O_3$ on the electrical and optical properties were investigated experimentally. Particularly in order to lower the electrical resistivity, positive and negative bias voltages were applied on the substrate, and the effect of bias voltage on the electrical properties of ZnO:Al thin film were also studied and discussed. Films with lowest resistivity of $4.3 \times 10 ^{-4} \Omega-cm$ and good transmittance of 91.46 % have been achieved for the films deposited at 1 mtorr, $400^{\circ}C$, 40 W, Al content of 2 wt% with a substrate bias of +30 V for about 800 nm in film thickness.

Protective Metal Oxide Coatings on Zinc-sulfide-based Phosphors and their Cathodoluminescence Properties

  • Oh, Sung-Il;Lee, Hyo-Sung;Kim, Kwang-Bok;Kang, Jun-Gill
    • Bulletin of the Korean Chemical Society
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    • v.31 no.12
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    • pp.3723-3729
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    • 2010
  • We investigated the high-excitation voltage cathodoluminescence (CL) performance of blue light-emitting (ZnS:Ag,Al,Cl) and green light-emitting (ZnS:Cu,Al) phosphors coated with metal oxides ($SiO_2$, $Al_2O_3$, and MgO). Hydrolysis of the metal oxide precursors tetraethoxysilane, aluminum isopropoxide, and magnesium nitrate, with subsequent heat annealing at $400^{\circ}C$, produced $SiO_2$ nanoparticles, an $Al_2O_3$ thin film, and MgO scale-type film, respectively, on the surface of the phosphors. Effects of the phosphor surface coatings on CL intensities and aging behavior of the phosphors were assessed using an accelerating voltage of 12 kV. The MgO thick film coverage exhibited less reduction in initial CL intensity and was most effective in improving aging degradation. Phosphors treated with a low concentration of magnesium nitrate maintained their initial CL intensities without aging degradation for 2000 s. In contrast, the $SiO_2$ and the $Al_2O_3$ coverages were ineffective in improving aging degradation.

Study on AlAs-doped ZnO Thin Film Properties (AlAs로 도핑된 ZnO 박막 특성에 대한 연구)

  • Nam, Hyoung-Gin;Cha, Kyung-Hwang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.5
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    • pp.1057-1061
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    • 2007
  • In this study, we investigated the properties of ZnO thin films prepared by layer-by-layer method in RF magnetron sputtering system using AlAs and ZnO targets. Effects of $H_2O_2$ dip prior to thermal treatment were studied as well. Either n-type or p-type films were observed in our study depending on the annealing conditions. It thus indicates the feasibility of arbitrarily modifying the conductivity type. At the same time, it also implies the thermal instabilities of the film properties. Property measurements after stressing the films up to 144 hours showed that thermal variations of properties nay be suppressed by pre-treatment in 30% $H_2O_2$ for 1 min.

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Threshold Voltage Control of Pentacene Thin-Film Transistor with Dual-Gate Structure

  • Koo, Jae-Bon;Ku, Chan-Hoe;Lim, Sang-Chul;Lee, Jung-Hun;Kim, Seong-Hyun;Lim, Jung-Wook;Yun, Sun-Jin;Yang, Yong-Suk;Suh, Kyung-Soo
    • Journal of Information Display
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    • v.7 no.3
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    • pp.27-30
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    • 2006
  • This paper presents a comprehensive study on threshold voltage $(V_{th})$ control of organic thin-film transistors (OTFTs) with dual-gate structure. The fabrication of dual-gate pentacene OTFTs using plasma-enhanced atomic layer deposited (PEALD) 150 nm thick $Al_{2}O_{3}$ as a bottom gate dielectric and 300 nm thick parylene or PEALD 200 nm thick $Al_{2}O_{3}$ as both a top gate dielectric and a passivation layer was investigated. The $V_{th}$ of OTFT with 300 nm thick parylene as a top gate dielectric was changed from 4.7 V to 1.3 V and that with PEALD 200 nm thick $Al_{2}O_{3}$ as a top gate dielectric was changed from 1.95 V to -9.8 V when the voltage bias of top gate electrode was changed from -10 V to 10 V. The change of $V_{th}$ of OTFT with dual-gate structure was successfully investigated by an analysis of electrostatic potential.