• Title/Summary/Keyword: B-SiC

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Complex Formation of Substituted Benzo-1,4,7,10,13-pentaoxacyclopentadecane (B15C5) with Nd(Ⅲ) (Nd(Ⅲ)과 치환된 Benzo-1,4,7,10,13-pentaoxacyclopentadecane (B15C5)와의 착물 형성에 관한 연구)

  • Kim, Hae-Joong;Kim, Jeong;Kim, Si-Joong
    • Journal of the Korean Chemical Society
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    • v.39 no.6
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    • pp.440-445
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    • 1995

  • The chemical compositions and stability constants, thermodynamic parameters for the neodymium(Ⅲ) complexes of substituted benzo-1,4,7,10,13-pentaoxacyclopentadecane(B15C5) have been determined by spectrophotometry and conductometry in methanol solution at various temperatures. As substituents, CH3, Br, CHO, NO2, and 3,4-(NO2)2 were used. In methanol solution the ratios of neodymium(Ⅲ) to the ligands in the complexes are 1 : 1. The stability constants were increased in order of B15C5-3,4-(NO2)2 < B15C5-NO2 < B15C5-CHO < B15C5-Br < B15C5 < B15C5-CH3. This observation can be explained in terms of the substituent effect. The order of stability constants was dimethylsulfoxide < acetone < acetonitrile in solution and the magnitudes were found to be inversely proportional to the solvents donicities. These results could be understood in terms of solvent basicity, ligand basicity, solvation of the cation, and entropy changes of complex formation.

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Crystallographic Characteristics of ZnO Films Deposited on SiO$_2$/Si Substrate

  • Park, H.D.;Kim, K.S.;Lee, C.S.;Kim, J.W.;Han, B.M.;Kim, S.Y.
    • Journal of Surface Science and Engineering
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    • v.28 no.6
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    • pp.386-392
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    • 1995

  • The RF planar magnetron sputtering technique was used to fabricate uniform ZnO/$SiO_2$/Si thin films at high growth rate. A detailed crystallographic character of these thin films has been carried oct using XRD, XRC, and SEM. These thin films have the configuration of c-axis orientation perpendicular to $SiO_2$/ Si substrate. The dependence of the thickness of ZnO/$SiO_2$/Si films on applied RF power parameters was also investigated. The crystallinity of films was improved as the substrate temperature was high, RF input power increased, and Ar/$O_2$ ratio decreased. Also, most of ZnO films fabricated on $SiO_2$/Si were suitable for SAW filter since a standard deviation of XRC (002) peak was less than $6^{\circ}$. The presence of the $SiO_2$ layer has a beneficial effect on the crystalline quality of the grown ZnO films.

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Preparation and properties of BaO-ZnO-$B_2O_3$-$V_2O_5$-$SiO_2$ Glass for PDP paste (PDP용 BaO-ZnO-$B_2O_3$-$V_2O_5$-$SiO_2$계 glass past의 제조와 특성)

  • Son, Myung-Mo;Lee, Heon-Soo;Lee, Chang-Hee;Lee, Sang-Geun;Park, Hee-Chan
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07b
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    • pp.1096-1099
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    • 2004

  • The principal problems in development of dielectric paste materials for PDP(plasma display panel)are PbO free paste and low melting temperature. We prepared PbO free paste from glasses in the system BaO-ZnO-$B_2O_3$-$V_2O_5$. DTA, and XRD were used to characterize BaO-ZnO-$B_2O_3$-$V_2O_5$ glasses. In this present study, PbO free paste had thermal expansion of $74\times10^{-7}/^{\circ}C$, DTA softening point of $460^{\circ}C$, and firing condition of $520^{\circ}C$, 20min

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Dielectric properties of bismuth magnesium niobate thin films deposited by sputtering using two main phase target in the system (두 메인 상의 타겟을 사용하여 스퍼터링으로 증착한 bismuth magnesium niobate 박막의 유전특성)

  • Ahn, Jun-Ku;Kim, Hae-Won;Yoon, Soon-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.264-264
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    • 2007

  • $B_2Mg_{2/3}/Nb_{4/3}O_7\;(B_2MN)$ thin films and $Bi_{3/2}MgNb_{3/2}O_7\;(B_{1.5}MN)$ thin films were deposited as a function of various deposition temperatures on Pt/$TiO_2/SiO_2$/Si substrates by radio frequency magnetron sputtering system. Both of their thin films are shown to crystalline phase at $500^{\circ}C$, deposition temperature, using 100W RF power. The composition of them and structural micro properties are investigated by RBS spectrum and SEM, AFM. 200 nm-thick $B_2MN$ thin films were deposited at room temperature had capacitance density of $151nF/cm^2$ at 100kHz, dissipation factor of 0.003 and had capacitance density of $584nF/cm^2$ at 100kHz, dissipation factor of 0.0045 at $500^{\circ}C$ deposition temperature. Both of their dielectric constant deposited at room temperature and at $500^{\circ}C$ were each approximately 40 and 100.

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Fabrecation and Characterization of $SrBi_2TaNbO_9$ Ferroelectric Thin Film Prepared by Sol-Gel Method (SOL-GEL법을 이용한 $SrBi_2TaNbO_9$ 강유전성 박막 제조 및 특성 평가)

  • 이진한;박상준;장건익
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.94-98
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    • 2000

  • Polycrystalline SBTN ferroelectric thin films were prepared by sol-gel method with various Nb mole ratios on Pt/ $SiO_2$/Si (100) substrates. The films were annealed at different temperatures and characterized in terms of phase and microstructure. Relatively a well saturated hysteresis pattern was obtained at x =0.2 in S $r_{0.8}$B $i_{2.3}$(T $a_{1-x}$ N $b_{x}$)$_2$ $O_{9+}$$\alpha$/ thin films. At an applied voltage of 5V, the dielectric constant ($\varepsilon$$_{r}$) and dissipation factor (tan $\delta$) of typical S $r_{0.8}$B $i_{2.3}$(T $a_{1-x}$ N $b_{x}$)$_2$ $O_{9+}$$\alpha$/ thin film (x=0.2) were about 236.2 and 0.034. Measured remanent polarization (2Pr) and coercive field (Ec) were 4.28C/c $m_2$, and 38.88kv/cm respectively. No fatigue was observed up to 6$\times$10$_{10}$ switching cycles at 5V and the normalized polarization reduced by a factor of only 4%.%. 4%.%. 4%.%.%.%.%.

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