• Title/Summary/Keyword: Gold thin-film

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Microwave properties of pulsed-laser SrTiO$_3$ thin films at low temperatures

  • Lee, G.D.;Kim, C.O.;Hong, J.P.;Kwak, J.S.
    • 한국초전도학회:학술대회논문집
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    • v.10
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    • pp.207-210
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    • 2000
  • Properties of SrTiO$_3$ thin films were characterized under the influence of an applied dc voltage utilizing a gold resonator with a flip-chip capacitor. The measurements were performed at microwave frequency ranges and low temperatures cryogenic temperatures. The dielectric constant of 830 and the low loss tangent of 6X10$^{-3}$ at 3.64 GHz were observed at 90 K and 100 V. The quality in the SrTiO$_3$ film was presented in terms of fractional frequency under the bias voltages and cryogenic temperatures.

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Quench characteristics of thin film type SFCLs with shunt layers of various thickness (션트박막 두께에 따른 박막형 초전도 한류소자의 ?치특성)

  • 김혜림;이승엽;차상도;최효상;현옥배
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.02a
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    • pp.51-54
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    • 2003
  • We investigated the quench characteristics of thin film type SFCLs with shunt layers of various thickness. The SFCLs ware based on 2 inch diameter YBa$_2$Cu$_3$O$_{7}$ thin films coated in-situ with a gold shunt layer. The shunt layer thickness was varied by Ar ion milling. The limiters were tested with simulated fault currents at various source voltages. The thinner the shunt layer was, the slower was the rise of SFCL temperatures. This means SFCLs of thinner shunt layers had higher voltage ratings. The voltage rating was approximately inversely proportional to the square root of the shunt layer thickness. This result could be understood through the concept of heat balance.e.

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Quench characteristics of thin film type SFCLs with shunt layers of various thickness (션트박막 두께에 따른 박막형 초전도 한류소자의 ?치특성)

  • 김혜림;이승엽;차상도;최효상;현옥배
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.02a
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    • pp.242-245
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    • 2003
  • We investigated the quench characteristics of thin film type SFCLs with shunt layers of various thickness. The SFCLs ware based on 2 inch diameter YBa$_2$Cu$_3$3O$_{7}$ thin films coated in-situ with a gold shunt layer. The shunt layer thickness was varied by Ar ion milling. The limiters were tested with simulated fault currents at various source voltages. The thinner the shunt layer was, the slower was the rise of SFCL temperatures. This means SFCLs of thinner shunt layers had higher voltage ratings. The voltage rating was approximately inversely proportional to the square root of the shunt layer thickness. This result could be understood through the concept of heat balance.e.

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Au Deposition Effect on Amorphous In-Ga-Zn-O Thin Film Investigated by High-Resolution x-ray Photoelectron Spectroscopy

  • Gang, Se-Jun;Baek, Jae-Yun;Sin, Hyeon-Jun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.301-301
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    • 2012
  • Amorphous In-Ga-Zn-O (a-IGZO)는 광학적으로 투명하고 높은 전자이동도를 가지고 있어서 차세대 thin-film-transistor의 channel layer 물질로 각광받고 있다. 이러한 a-IGZO를 TFT channel layer로 사용하기 위해서는 소스 드레인 전극물질과 IGZO박막의 계면에서 ohmic contact을 만드는 것도 중요하다. 하지만 산화물 반도체의 특성상 금속물질을 증착시킬 때 산화금속계면을 형성하기 때문에 ohmic contact이 형성되기 어려운 것으로 알려져 있다. Au는 보통 전극물질로 많이 사용되는데, 이는 전기전도도가 매우 높고, 독특한 산화환원반응 특성을 보이지만, 화학반응을 잘 일으키지 않는 안정성을 가지는 성질에 기인한다. 본 연구진은 Au가 a-IGZO에 증착 시에 일어나는 표면의 화학적 상태변화를 이해하기 위해 방사광을 이용한 고분해능 광전자 분광법을 이용하여 표면변화를 분석하였다. Au는 (Au 4f) 증착 초기엔 약간의 gold oxide가 함께 형성되지만, 주로 metal gold의 형태로 존재하였다. In 3d, Ga 3d, O 1s, Zn 3d 각각의 스펙트럼에서는 Au 증착으로 인해 낮은 결합에너지에 새로운 state가 나타났다. 한편, In은 상대적으로 다른 원소들에 비해 Au와 좀 더 결합을 잘 하는 것으로 나타났는데 이는, In 5s 전자궤도가 전도메커니즘에서 중요한 역할을 하기 때문에, In-Au의 상대적인 강한 결합은 a-IGZO의 전기적 특성 변화에 기여할 수 있음을 의미한다.

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A Study on the Negative Differential Resistance Properties of Self-Assembly Organic Thin Film with Nitro Group (니트로기를 가진 자기조립된 유기 초박막의 부성미분저항 특성에 관한 연구)

  • Kim, Seung-Un;Son, Jung-Ho;Kim, Byoung-Sang;Shin, Hoon-Kyu;Kwon, Young-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.811-813
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    • 2003
  • We investigated the electrical properties of self-assembled (4,4'-Di(ethynylphenyl)-2'-nitro-1-thioacetylbenzene), which has been well known as a conducting molecule having possible application to molecular level negative differential resistance(NDR)[1]. Generally, the phenomenon of NDR can be characterized by the decreasing current with the increasing voltage[2]. To deposit the SAM layer onto gold electrode, we transfer the prefabricated nanopores into a 1mM self-assembly molecules in THF solution. Au(111) substrates were prepared by ion beam sputtering method of gold onto the silicon wafer. As a result, we measured the voltage-current properties and confirmed the negative differential resistance properties of self-assembled organic thin film and measured, using Scanning Tunneling Microscopy(STM).

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Etching Characteristics of Gold Thin Films using Inductively Coupled CF4/CI2/Ar Plasma (CF4/CI2/Ar유도 결합 플라즈마에 의한 gold 박막의 식각특성)

  • 김창일;장윤성;김동표;장의구
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.7
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    • pp.564-568
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    • 2003
  • The etching of Au thin films have been performed in an inductively coupled CF$_4$/Cl$_2$/Ar plasma. The etch rates were measured as CF$_4$ contents added from 0 to 30 % to Cl$_2$/Ar plasma, of which gas mixing ratio was fixed at 20%. Other parameters were fixed at an rf power of 700 W, a dc bias voltage of 150 V, a chamber pressure of 15 mTorr, and a substrate temperature of 3$0^{\circ}C$. The highest etch rate of the Au thin film was 3700 $\AA$m/min at a 10% additive CF$_4$ into Cl$_2$/Ar plasma. The surface reaction of the etched Au thin films was investigated using x-ray photoelectron spectroscopy (XPS) analysis. XPS analysis indicated that Au reacted with Cl and formed Au-Cl, which is hard to remove on the surface because of its high melting point. The etching products could be sputtered by Ar ion bombardment.

Development of Nanostructured Light-Absorbers for Ultrasound Generation by Using a Solution-Based Process

  • Sang, Pil Gyu;Heo, Jeongmin;Song, Ju Ho;Thakur, Ujwal;Park, Hui Joon;Baac, Hyoung Won
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.377-377
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    • 2016
  • Under nanosecond-pulsed laser irradiation, light-absorbing thin films have been used for photoacoustic transmitters for ultrasound generation. Especially, nanostructured absorbers are attractive due to high optical absorption and efficient thermoacoustic energy conversion: for example, 2-dimensional (2-D) gold nanostructure array, synthetic gold nanoparticles, carbon nanotubes (CNTs), and reduced graphene oxides. Among them, CNT has been used to fabricate a composite film with polydimethylsiloxane (PDMS) that exhibits excellent photoacoustic conversion performance for high-frequency, high-amplitude ultrasound generation. Previously, CNT-PDMS nanocomposite films were made by using a high-temperature chemical vapor deposition (HTCVD) process for CNT growth. However, this approach is not suitable to fabricate large-area CNT films (>several cm2). This is because a chamber dimension of HTCVD is limited and also the process often causes nonuniform CNT growth when the film area increases. As an alternative approach, a solution-based process can be used to overcome these issues. We develop PDMS composite transmitters, based on the solution process, using several nanostructured light-absorbers such as CNTs, nanoink powders, and imprinted regular arrays of gold nanostructure. We compare fabrication processes of each composite transmitters and photoacoustic output performance.

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Fabrication of Nanoscale Metal Nanobeam Specimens and Evaluation of the Mechanical Properties of Gold Thin Film Nanostructures (나노스케일의 금속 나노빔 시험편 제작 및 이를 이용한 금 박막 나노 구조물의 기계적 물성 평가)

  • Baek, Chang-Wook;Hyeon, Ik-Jae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.7
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    • pp.1294-1297
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    • 2007
  • In this paper, fabrication techniques for nanoscale metallic nanobeam specimens have been proposed, and mechanical properties of the fabricated gold nanobeams have been evaluated by nanoindentation techniques and nanobeam bending test. Elastic modulus and hardness of gold nanobeams were measured to be $109.6\;{\pm}\;10\;GPa\;and\;1.73\;{\pm}\;0.3\;GPa$, respectively, from the nanoindentation test, while elastic modulus was $241\;{\pm}\;7\;GPa$ from the nanobeam bending test.

Analysis on Recovery in Au/YBCO thin Film Meander Lines (Au/YBCO 박막 곡선에서의 회복 분석)

  • Kim, H.R.;Yim, S.W.;Oh, S.Y.;Hyun, O.B.
    • Progress in Superconductivity
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    • v.9 no.1
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    • pp.119-125
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    • 2007
  • We investigated recovery in $Au/YBa_2Cu_3O_7$ (YBCO) thin film meander lines on sapphire substrates. The meander lines were fabricated by patterning YBCO films coated with gold layers. The lines were subjected to simulated AC fault current and then small current was applied for recovery measurements. The samples were immersed in liquid nitrogen during the experiment. After the fault, the resistance decreased linearly, first slowly and then fast to zero. The initial slow decrease was due to the decrease of the meander line temperature, whereas the fast decrease was originated from the transition from the normal state to the superconducting state. The recovery speed depended on the size of samples, and was faster in the smaller samples during the whole period of recovery. The experimental results were analyzed quantitatively with the concept of heat transfer within the sample and to the surrounding liquid nitrogen. A heat balance equation was solved for the initial phase of recovery, and an expression for the time dependence of resistance was obtained. The result agreed with data well.

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Control of the Gold Electrode Work Function for High Performance Organic Thin Film Transistors (표면개질된 금 전극의 일함수 조절을 통한 고성능 유기박막 트랜지스터 개발)

  • Park, Yeong Don
    • Applied Chemistry for Engineering
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    • v.23 no.3
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    • pp.289-292
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    • 2012
  • Au electrodes modified with self-assembled monolayers (SAMs) were used to control the work function of source/drain electrodes in triethylsilylethynyl anthradithiophene (TES ADT)-based organic thin film transistors (OTFTs). By using benzothiol (BT) and pentafluorobenzothiol (PFBT) SAMs, the hole injection barrier between Au and the highest occupied molecular orbital (HOMO) of TES ADT was controlled. After a solvent annealing, TES ADT OTFTs with PFBT SAM-treated Au electrodes were found to exhibit high field-effect mobilities of $0.05\;cm^2/Vs$ and on/off current ratios of $10^6$.