• Title/Summary/Keyword: ultrathin film

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Optical and Electrical Characteristics of viologen-diTCNQ thin film prepared by Langmuir-Blodgett Technique (LB법을 이용한 viologen-diTCNQ 박막의 광학적 및 전기적 특성)

  • 이용수;신동명;김태완;강도열
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.04a
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    • pp.45-48
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    • 1997
  • Enhancing the electrical conductivity of the ultrathin organic films is one of the important factors for the development of molecular electronic devices. The Langmuir-Blodgett(LB) technique has recently been attracted interest as the a method of deposition ultrathin films. We have fabricated N-docosyl-N'-methyl viologen-diTCNQ(DMVT) anion radical LB film and investigated the optical and electrical conductivity. We have measured UV/visible and FT-lR spectrum. In ESR spectrum, we confirmed that a half-amplitude linewidth is clearly dependent on both temperature and incident angle, which indicates conducting species change. The in-plane electrical conductivity of 21 layers is approximately 1.37$\times$10$^{-6}$ (S/cm).

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Ultrathin Polymer Networks of Itaconic Acid Copolymers and Poly(allkylamine) by the ;angmuir-Blodgett Technique

  • 최기선;이범종;장상목;권영수
    • Bulletin of the Korean Chemical Society
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    • v.16 no.6
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    • pp.493-498
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    • 1995
  • Ultrathin networks of itaconic acid copolymers and poly(allylamine) were produced by a Langmuir-Blodgett (LB) technique employing a double-chain amine as a monolayer template which was subsequently removed by extraction after thermal crosslinking. Itaconic acid copolymers used were copoly (itaconic acid-ethyl vinyl ether) and copoly (itaconic acid-n-butyl vinyl ether). The polyion-complexed monolayers of three components consisting of template amine, itaconic acid copolymer and poly (allylamine) were formed at the air-water interface. The Langmuir film properties have been studied by the surface pressure-area isotherm and fluorescence microscopy. The monolayers were transferred on solid substrates and were characterized by FT-IR spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy (SEM). Two-dimensional polymer networks were formed through imide or amide linkages by heat treatment under vacuum. The heat-treated films were extracted with chloroform after immersion in aq. sodium chloride to remove the template amines. SEM observation of a LB film on a porous fluorocarbon membrane filter with pore diameter of 0.1 μm showed covering of the pores by six layers in the polyion complex state.

Ultrathin Fe film on MgO(001)

  • Park, Hyeon-Guk;Yang, Seol-Un;Kim, Jae-Yeong;Park, Byeong-Gyu;Kim, Jae-Seong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2009.08a
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    • pp.339-339
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    • 2009
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A Study on the Deposition Condition and Molecular Orientation of the Ultrathin Organic Films using the Langmuir-Blodgett Technique (Langmuir-Blodgett 법을 이용한 유기초박막의 제작조건 및 분자배향에 관한 연구)

  • 김태완;신동명;최강훈;권영수;강도열
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.43 no.2
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    • pp.303-311
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    • 1994
  • Optimum conditions for the deposition of N-docosylquinolium-TCNQ ultrathin organic films using the Langmuir-Blodgett etchnique and the molecular orientation and alignment of the LB films were studied. The $\pi$-A isotherm of the N-docosylquinolium-TCNQ was measured at the air-water interface varying with the subphase temperature, subphase pH, compressing speed and amounts of solutions for spreading. The LB film was deposited under the surface pressure of 30mN.m and 45mN/m and other deposition conditions. The molecular orientation and alignment of the LB films were studied by the polarization absorption technique. The $\pi$-A isotherm showed that the stable N-docosylquinolium -TCNQ monolayer was formed on the water surface at the condition of 25$^{\circ}C$,pH 5.6, molecular density of 2.1${\times}$10S014T~2.6${\times}$10S014T/cmS02T. The LB film was deposited under the surface pressure of 45mN/m had better packing density, orientation and alignment than the film of 30mN/m.

An Ultrathin Polymer Network through Polyion-Complex by Using Sodium Dioctadecyl Sulfate as Monolayer Template

  • Lee, Burm-Jong;Kim, Hee-Sang;Kim, Seong-Hoon;Son, Eun-Mi;Kim, Dong-Kyoo;Shin, Hoon-Kyu;Kwon, Young-Su
    • Bulletin of the Korean Chemical Society
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    • v.23 no.4
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    • pp.575-579
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    • 2002
  • Two-dimensionally cross-linked ultrathin films of poly(maleic acid-alt-methyl vinyl ether) (MA-MVE) and poly(allylamine) (PAA) were produced by using sodium dioctadecyl sulfate (2C18S) as the monolayer template for Langmuir-Blodgett (LB) depositio n. The template molecules were subsequently removed by thermal treatment followed by extraction. The polyion-complexed monolayers of three components, i.e., template 2C18S, co-spread PAA, and subphase MA-MVE, were formed at the air-water interface. Their monolayer properties were studied by the surface pressure-area isotherm. The monolayers were transferred on solid substrates as Y type. The polyion-complexed LB films and the resulting network films were characterized by FT-IR spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The cross-linking to form a polymer network was achieved by amide or imide formation through heat treatment under a vacuum. SEM observation of the film on a porous fluorocarbon membrane filter (pore diameter 0.1 ㎛) showed covering of the pores by four layers in the polyion complex state. Extraction by chloroform followed by heat treatment produced hole defects in the film.

Improvement of Barrier Property of LDPE Food Packaging Film by Plasma Polymerization (플라스마 중합을 이용한 LDPE 식품포장 필름의 차단성 향상)

  • Kim, Kyoung-Seok;Cho, Dong-Lyun
    • Polymer(Korea)
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    • v.32 no.1
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    • pp.38-42
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    • 2008
  • Ultrathin films were coated on low density Polyethylene (LDPE) food packaging films by plasma polymerization of methane, acetylene, hexamethyldisiloxane (HMDSO), and HMDSO+oxygen to improve the barrier property of the LDPE films. The film coated in HMDSO +oxygen (flow rate: 0.6+ 9.0 SCCM) plasma at 40 W for 10 min showed the highest improvement in the barrier property against oxygen, reducing the permeability of oxygen as much as 18.6 times. The film coated in acetylene (flow rate 0.75 SCCM) plasma at 10 W for 10 min showed the highest improvement in the barrier property against carbon dioxide and moisture, reducing the permeability of carbon dioxide and moisture as much as 12.0 and 3.0 times, respectively. In addition, cherry tomato, cucumber, and mushroom (Flammulina velutipes) wrapped with the coated films were kept fresh $1.5{\sim}3.0$ times longer than those wrapped with an LDPE film.

Quantitative Analysis of Ultrathin SiO2 Interfacial Layer by AES Depth Profilitng

  • Soh, Ju-Won;Kim, Jong-Seok;Lee, Won-Jong
    • The Korean Journal of Ceramics
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    • v.1 no.1
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    • pp.7-12
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    • 1995
  • When a $Ta_O_5$ dielectric film is deposited on a bare silicon, the growth of $SiO_2$ at the $Ta_O_5$/Si interface cannot be avoided. Even though the $SiO_2$ layer is ultrathin (a few nm), it has great effects on the electrical properties of the capacitor. The concentration depth profiles of the ultrathin interfacial $SiO_2$ and $SiO_2/Si_3N_4$ layers were obtained using an Auger electron spectroscopy (AES) equipped with a cylindrical mirror analyzer (CMA). These AES depth profiles were quantitatively analyzed by comparing with the theoretical depth profiles which were obtained by considering the inelastic mean free path of Auger electrons and the angular acceptance function of CMA. The direct measurement of the interfacial layer thicknesses by using a high resolution cross-sectional TEM confirmed the accuracy of the AES depth analysis. The $SiO_2/Si_3N_4$ double layers, which were not distinguishable from each other under the TEM observation, could be effectively analyzed by the AES depth profiling technique.

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