• Title/Summary/Keyword: CdS:H

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Flexible CdS Films for Selective control of Transmission of Electromagnetic Wave (유연성 기판위에 스퍼터링법으로 제조한 CdS 박막의 전자파차폐 특성평가)

  • Hur, Sung-Gi;Cho, Hyun-Jin;Jung, Hyun-Jun;Ahn, Jun-Ku;Yoon, Soon-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.27-27
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    • 2009
  • Non-stochiometric CdS:H films grown on polyethersulfon (PES) flexible polymer substrates at room temperature by R.F. sputtering technique. They exhibited a dark- and photo-sheet resistance of $2.7\times10^5$ and $\sim\;50\;{\Omega}$/square, respectively. These values were realized by an optimum control of both hydrogen doping-levels and the surface morphologies of the films. The comparison between the real and the simulated results for the shielding and the transmission by the free space measurement system in the X-band frequency range (8.2 - 12.4 GHz) was also addressed in this study. Samples overlapped with 13 layers of CdS:H/PES were consistent with the transmission results of pure aluminum metal films ($0.1\;{\Omega}$/square) deposited on PES substrates. As a result, by the simples tacking of the CdS:H/PES layers, the perfect control of the shielding and the transmission of the EM wave in the range of X-band frequency is possible by avisible light alone, and their results are especially very outstanding findings in the stealth function of the radome(Radar+Dome) such as aircrafts, ships, and missiles.

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Growth of Thin Film using Chemical Bath Deposition Method and Their Photoconductive Characterics ($Cd_{1-x}Zn_{x}S$ 박막의 성장과 광전도 특성)

  • Lee, S.Y.;Hong, K.J.;You, S.H.;Shin, Y.J.;Lee, K.K.;Suh, S.S.;Kim, H.S.;Yun, E.H.;Kim, S.U.;Park, H.S.;Shin, Y.J.;Jeong, T.S.;Shin, H.K.;Kim, T.S.;Moon, J.D.;Lee, C.I.;Jeon, S.L.
    • Journal of Sensor Science and Technology
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    • v.4 no.3
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    • pp.60-70
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    • 1995
  • Polycrystalline $Cd_{1-x}Zn_{x}S$ thin film were grown on slide glass(corning-2948) substrate using a chemical bath deposition (C.B.D) method. They were annealed at various temperature and X -ray diffraction patterns were measured by X-ray diffractometor in order to study $Cd_{1-x}Zn_{x}S$ polycrystal structure using extrapolation method of X-ray diffraction patterns for the CdS, ZnS sample annealed in $N_{2}$ gas at $550^{\circ}C$. It was found hexagonal structure which had the lattice constant $a_{0}\;=\;4.1364{\AA}$, $c_{0}\;=\;6.7129{\AA}$ in CdS and $a_{0}\;=\;3.8062{\AA}$, $c_{0}\;=\;6.2681{\AA}$ in ZnS, respectively. Hall effect on these sample was measured by Van der Pauw method and then studied on carrier density and mobility depending on temperature. We measured also spectral response, sensitivity maximum allowable power dissipation and response time on these sample.

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Photoelectrochemical Cell Study on Closely Arranged Vertical Nanorod Bundles of CdSe and Zn doped CdSe Films

  • Soundararajan, D.;Yoon, J.K.;Kwon, J.S.;Kim, Y.I.;Kim, S.H.;Park, J.H.;Kim, Y.J.;Park, D.Y.;Kim, B.C.;Wallac, G.G.;Ko, J.M.
    • Bulletin of the Korean Chemical Society
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    • v.31 no.8
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    • pp.2185-2189
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    • 2010
  • Closely arranged CdSe and Zn doped CdSe vertical nanorod bundles were grown directly on FTO coated glass by using electrodeposition method. Structural analysis by XRD showed the hexagonal phase without any precipitates related to Zn. FE-SEM image showed end capped vertically aligned nanorods arranged closely. From the UV-vis transmittance spectra, band gap energy was found to vary between 1.94 and 1.98 eV due to the incorporation of Zn. Solar cell parameters were obtained by assembling photoelectrochemical cells using CdSe and CdSe:Zn photoanodes, Pt cathode and polysulfide (1M $Na_2S$ + 1M S + 1M NaOH) electrolyte. The efficiency was found to increase from 0.16 to 0.22 upon Zn doping. Electrochemical impedance spectra (EIS) indicate that the charge-transfer resistance on the FTO/CdSe/polysulfide interface was greater than on FTO/CdSe:Zn/polysulfide. Cyclic voltammetry results also indicate that the FTO/CdSe:Zn/polysulfide showed higher activity towards polysulfide redox reaction than that of FTO/CdSe/polysulfide.

Adsorption of Heavy Metal onto the Extracellular Polysaccharide Produced by the Purple Nonsulfur Photosynthetic Bacteria Rhodopseudomonas sp. KH4 (홍색 비황 광합성 세균 Rhodopseudomonas sp. KH4의 Extracellular polysaccharide의 중금속 흡착)

  • Jeong, Jeong-Hwa;Seo, Pil-Soo;Kong, Sung-Ho;Lee, Jong-Yeol;Lee, Sang-Seob
    • Korean Journal of Microbiology
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    • v.42 no.4
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    • pp.326-331
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    • 2006
  • In the present study, we examined biosorption characteristics of heavy metals onto the extracellular polysaccharide (EPS) produced by the purple nonsulfur photosynthetic bacteria Rhodopseudomonas sp. KH4, which was isolated from a stream in Anyang, Kyonggi-Do. When Cd (100 mg/L) and Cu (100 mg/L) were added to EPS (1.0 g/L) in the optimal condition (Cd; pH 8, Cu; pH 5, $40^{\circ}C$), 84.2 mg/L of Cd and 70.0 mg/L of Cu were adsorbed within 30 min and 10 min, respectively. When 100 mg/L of Cd and Cu were present as mixture, 16.8 mg/L of Cd and 48.7 mg/L of Cu were adsorbed at $25^{\circ}C$, pH 5. The maximum adsorption capacity determined by fitting Langmuir isotherms model was suitable for describing the biosorption of Cd (76.9 mg/g) and Cu (67.1 mg/g) by EPS. The neutral monosaccharide in the EPS determined by GC consisted of arabinose (2.4%), glucose (7.1%) and mannose (90.5%).

Crystal Growth of Cd4GeS6 and Cd4GeS6:Co2+Single Crystals ($Cd_{4}GeS_{6}$$Cd_{4}GeS_{6}:Co^{2+}$ 단결정의 성장)

  • Kim, D.T.;Kim, H.G.;Kim, N.O.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11b
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    • pp.1-6
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    • 2004
  • In this paper author describe the undoped and $Co^{2+}$ (0.5mole%)doped $Cd_4GeS_6$ single crystals were grown by the chemical transporting reaction(CTR) method using high purity(6N) Cd, $GeS_2$, S elements. It was found from the analysis of X-ray diffraction that the undoped and $Co^{2+}$(0.5mole%) doped $Cd_{4}GeS_{6}$ compounds have a monoclinic structure in space grop Cc. The optical energy band gap was direct band gap and temperature dependence of optical energy gap was fitted well to Varshni equation. Impurity optical absorption peaks due to the doped cobalt in the $Cd_4GeS_6:Co^{2+}$ single crystal were observed at 3593cm-1, 5048cm-1, 5901cm-1, 7322cm-1, 12834cm-1, 13250cm-1, 14250cm-1,and 14975cm-1 at 11.3K.

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The analysis on the optical properties of $Cd_1-_xZn_xS$ films deposited by CBD method (CBD법을 이용한 Cd1-xZnxS 박막의 광학적 특성분석)

  • Son, W.C.;Lee, J.H.;Kim, J.H.;Moon, J.S.;Park, Y.K.;Yang, K.J.
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.1649-1651
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    • 2000
  • Optical properties of $Cd_{1-x}Zn_{x}S$ films deposited by :chemical bath deposition(CBD), which is a very attractive method for low-cost and large-area solar cells, are presented, Especially, in order to control more effectively the zinc component of the films, zinc acetate, which used as the zinc source, mixed in reaction solution after preheating and the pH of the reaction solution decreased with increasing the concentration of zinc acetate. The films prepared after preheating and pH control had larger zinc component and higher optical band gap. As the more zinc substituted for Cd in the films, the optical transmittance improved, while the absorption edge shifts to a shorter wavelength and the optical band gap increased. The photo conductivity of the films was larger than the dark conductivity, while the ratio of those increased with increasing the mole ratio of zinc acetate.

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Entrapment of Milk Nutrients during Cholesterol Removal from Milk by Crosslinked β-Cyclodextrin

  • Ha, H.J.;Jeon, S.S.;Chang, Y.H.;Kwak, H.S.
    • Food Science of Animal Resources
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    • v.29 no.5
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    • pp.566-572
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    • 2009
  • This study was designed to elucidate the quantities of milk nutrients entrapped during cholesterol removal from milk by crosslinked $\beta$-cyclodextrin ($\beta$-CD, 0.4~1.2%, w/v) and to evaluate the amounts of the residual $\beta$-CD in cholesterol-reduced milk treated by crosslinked $\beta$-CD. The content of lactose in the control milk (without treatment by crosslinked $\beta$-CD) was 4.86%, and the amounts of lactose entrapped by crosslinked $\beta$-CD ranged from 0.00 to 0.03%. The total amounts of the entrapped short-chain free fatty acid (FFA) and free amino acid (FAA) ranged from 0.03 to 0.09 ppm and from 0.28 to $0.71{\mu}mol/mL$, respectively. The amounts of the entrapped water-soluble vitamins (L-ascorbic acid, niacin, thiamine and riboflavin) ranged from 0.02 to 0.05 ppm, 0.01 to 0.06 ppm, 0.00 to 0.06 ppm and 0.01 to 0.06 ppm, respectively. The entrapped amounts of lactose, short-chain FFAs, FAAs and water-soluble vitamins were not remarkably affected by the concentrations of crosslinked $\beta$-CD (0.4~1.2%, w/v). Only very small amounts of residual $\beta$-CD in the cholesterol-removed milk were measured (1.22~3.00 ppm). Based on the data obtained from the present study, it was concluded that the amounts of entrapped nutrients were negligible during cholesterol removal from milk by crosslinked $\beta$-CD, and only trace amounts of residual $\beta$-CD were present in cholesterol-removed milk.

Growth mechanism of anodic oxide for MCT passivation (MCT 표면보호를 위한 양극산화막 성장)

  • 정진원;왕진석
    • Electrical & Electronic Materials
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    • v.8 no.3
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    • pp.352-356
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    • 1995
  • Native oxide layer on MCT (HgCdTe) has been grown uniformly in H$\_$2/O$\_$2/ electrolyte through anodic oxidation method. It has been determined that anodic oxidation of HgCdTe in H$\_$2/O$\_$2/ electrolyte proceeds immediately with the input of constant currents without any induction time required for anodic oxideation in KOH electrolyte. Oxide layer with the resistivity of 2*10$\^$10/.ohm.cm and the refractive index of 2.1 suggested the possibility of well matching combination layer with ZnS for MCT MIS device. XPS results indicated that the major components of oxide layer grown in H202 solution is TeO$\_$2/ with the possibility of small amounts of CdTeO$\_$3/.

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Crystal Growth Sensor Development of II-VI Compound Semiconductor : CdS (II-VI족 화합물 반도체의 결정성장 및 센서 개발에 관한 연구)

  • D.I. Yang;Y.J. Shin;S.Y. Lim;Y.D. Choi
    • Journal of the Korean Vacuum Society
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    • v.1 no.1
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    • pp.126-133
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    • 1992
  • This study deals with the crystal growth and the optical characteristics of CdS thin films activatedby silver. CdS:Ag thin films were deposited by using an electron beam evaporation(EBE) technique in vacuumof 1.5X 10-'torr, voltage of 4 kV, current of 2.5 mA and substrate temperature of 250$^{\circ}$C CdS:Ag photoconductivefilms prepared by EBE method show high photoconductivity after annealing at about 550"c for 0.5 h in air andAr gas.The grain size of CdS:Ag thin films annealed in Ar atmosphere (1 atm) was grown over 1 ym and the thicknessof the films is 4-5 pm. The analysis of X-ray diffraction patterns shows that the crystal structures are hexagonal.The diffraction line by (00.2) plane can only be observed, indicating that c-axis of hexagonal grows preferentiallyperpendicular to the substrate. The profiles of photoluminescence spectra of CdS:Ag films show Gaussian typecurves at room temperature, the maximum peak spectral sensitivity of CdS:Ag is located at the wavelength of520 nm.We annealed CdS:Ag thin films in air and Ar vapor in order to make the CdS photoconductors having theintensive photocurrent, the broad distribution of the photocurrent spectrum and the large value of the ratioof the photocurrent (pc) to the dark current(dc). We found that CdS:Ag thin films annealed in air atmospherewas the best one.air atmosphere was the best one.

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Effect of metals(Cd & Zn) and its nitrogen compounds on growth of bacteria isolated from the three tributaries and lower reach(Mulgum) of the Nakdong River (낙동강 하류(물금)와 세 지류에서 분리된 우점 세균의 증식에 미치는 금속(Cd & Zn) 및 그 질소 화합물의 영향)

  • Park, Jae-Rim;Son, Yeon-Ju;Ha, Kyung;Park, Joong-Chul
    • Journal of Environmental Science International
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    • v.11 no.3
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    • pp.183-189
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    • 2002
  • Investigation was carried out to observe the dominant bacteria and the effect of metals(Cd & Zn) and its nitrate compound on growth of bacteria isolated from the three tributaries and lower reach of the Nakdong River. Mean CFU(log$_{10}$) level was highest in Kumho River(8.30 CFU), Nam River, Hwang River, and Mulgum followed. Staphylococcus xylosus, Staph. lentus, Pasteurella pneumotropica, Aeromonas hydrophilla were dominant species in each study site. Cadmium powder and Zinc powder showed strong effect to inhibit the growth of Micrococcus spp., Pasteurella pneumotropica, Aeromonas hydrophilla. But, nitrate compounds of Cd and Zn(Cd(NO$_3$)$_2$4$H_2O$, Zn(NO$_3$)$_2$6$H_2O$) did not clearly show the strong effect to inhibit the growth of dominants.s.