• Title/Summary/Keyword: Nanoparticle deposition

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Growth of Silicon Nanowire Arrays Based on Metal-Assisted Etching

  • Sihn, Donghee;Sohn, Honglae
    • Journal of Integrative Natural Science
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    • v.5 no.4
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    • pp.211-215
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    • 2012
  • Single-crystalline silicon nanowire arrays (SiNWAs) using electroless metal-assisted etchings of p-type silicon were successfully fabricated. Ag nanoparticle deposition on silicon wafers in HF solution acted as a localized micro-electrochemical redox reaction process in which both anodic and cathodic process took place simultaneously at the silicon surface to give SiNWAs. The growth effect of SiNWs was investigated by changing of etching times. The morphologies of SiNWAs were obtained by SEM observation. Well-aligned nanowire arrays perpendicular to the surface of the silicon substrate were produced. Optical characteristics of SiNWs were measured by FT-IR spectroscopy and indicated that the surface of SiNWs are terminated with hydrogen. The thicknesses and lengths of SiNWs are typically 150-250 nm and 2 to 5 microns, respectively.

Experimental study on CIS thin film deposition via electrostatic spray technique (정전기 스프레이 기술을 이용한 CIS 박막코팅에 관한 실험적 연구)

  • Yoon, Hyun;Yoon, Sukgoo;Kim, Hoyoung
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.37.2-37.2
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    • 2010
  • Electrostatic spray deposition is an innovative coating technique that produces fine, uniform, self-dispersive (due to the Coulombic repulsion), and highly wettable, atomized drops. Copper-indium salts are dissolved in an alcohol-based solvent, which is then electrostatically sprayed onto a moderately heated, molybdenum-coated substrate. Solvent flowrates range from 0.02 to 5 ml/hr under applied voltages of 1 to 20 kV yielding drop sizes around a few hundred nanometers. By comparing the scanning electron miscrscope images of coated samples, the substrate temperature, applied voltage, solvent flowrate, and nozzle-substrate distance are demonstrated to be the primary parameters controlling coating quality. Also, the most stable electrostatic spray mode that reliably produces uniform and fine drops is the cone-jet mode with a Taylor cone issuing from the nozzle.

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Development of Particle Deposition System for Cleaning Process Evaluation in Semiconductor Fabrication (반도체 세정 공정 평가를 위한 나노입자 안착 시스템 개발)

  • Nam, Kyung-Tag;Kim, Young-Gil;Kim, Ho-Joong;Kim, Tae-Sung
    • Journal of the Semiconductor & Display Technology
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    • v.6 no.4
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    • pp.49-52
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    • 2007
  • As the minimum feature size decrease, control of contamination by nanoparticles is getting more attention in semiconductor process. Cleaning technology which removes nanoparticles is essential to increase yield. A reference wafer on which particles with known size and number are deposited is needed to evaluate the cleaning process. We simulated particle trajectories in the chamber by using FLUENT. Charged monodisperse particles are generated using SMPS (Scanning Mobility Particle Sizer) and deposited on the wafer by electrostatic force. The Experimental results agreed with the simulation results well. We calculate the particles loss in pipe flow theoretically and compare with the experimental results.

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Plasma Synthesis of Silicon Nanoparticles for Next Generation Photovoltaics

  • Kim, Ka-Hyun;Kim, Dong Suk
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.135.1-135.1
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    • 2014
  • Silicon nanoparticles can be synthesized in a standard radio-frequency glow discharge system at low temperature (${\sim}200^{\circ}C$). Plasma synthesis of silicon nanoparticles, initially a side effect of powder formation, has become over the years an exciting field of research which has opened the way to new opportunities in the field of materials deposition and their application to optoelectronic devices. Hydrogenated polymorphous silicon (pm-Si:H) has a peculiar microstructure, namely a small volume fraction of plasma synthesized silicon nanoparticles embedded in an amorphous matrix, which originates from the unique deposition mechanism. Detailed discussion on plasma synthesis of silicon nanoparticles, growth mechanism and photovoltaic application of pm-Si:H will be presented.

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Chemically Modified Superhydrophobic Zinc Oxide nanoparticle surface

  • Lee, Mi-Gyeong;Gwak, Geun-Jae;Yong, Gi-Jung
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.448-448
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    • 2011
  • We investigated the fabrication method of superhydrophobic nanocoating prepared by a simple spin-coating and the chemisorption of fatty acid. The resulting coating showed a tremendous water repellency (static water contact angle = $154^{\circ}$) and the water contact angle can be modulated by changing the number of deposition cycles of ZnO and the carbon length of Self-Assembled Monolayers (SAM). Varying the number of deposition cycles of ZnO controlled the surface roughness, and affected to the superhydrophobicity. This simple coating method can be universally applicable to any substrates including flexible surfaces, papers and cotton fabrics, which can effectively be used in various potential applications. We also observed the thermal and dynamic stabilities of SAM on ZnO nanoparticles. The superhydrophobicic surface maintained its superhydrophobic properties below $250^{\circ}C$ and under dynamic conditions.

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Chemical Bath Deposition and the Optical Properties of Nanostructured ZnS Thin Films (용액성장법에 의한 ZnS 나노 박막의 제작과 광학적 특성)

  • 이현주;전덕영;이수일
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.739-742
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    • 2000
  • Nanostructured ZnS thin films were grown on the slide glass substrate by the chemical bath deposition using an aqueous so1ution Of ZnSO$_4$and CH$_3$CSNH$_2$at 95$^{\circ}C$. The average grain sizes of the ZnS thin film estimating from the Debye-Scherrer formula are 4.8 nm. The optical transmittance edge of the ZnS thin films (4.0 eV) was shifted to the shelter wavelength compared with that of the bulk ZnS (3.67 eV) due to the quantum size effects. The ZnS thin films showed a strong photoluminescence intensity and a sharp emission band from 410 to 480 nm 3t room temperature. The PWHM of photoluminescence peak was about 40 nm. For the viloet(410 nm) and blue(480 nm) emission of the ZnS thin films, the temperature dependence can be described by an Arrhenius equation with an activation energy of 168 and 157 meV, respectively.

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Revealing Strong Metal Support Interaction during CO Oxidation with Metal Nanoparticle on Reducible Oxide Substrates

  • Park, Dahee;Kim, Sun Mi;Qadir, Kamran;Park, Jeong Young
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.264-264
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    • 2013
  • Strong metal-support interaction effect is an important issue in determining the catalytic ac-tivity for heterogeneous catalysis. In this study, we investigated the support effect and the role of organic capping layers of two-dimensional Pt nanocatalysts on reducible metal oxide supports under the CO oxidation. Several reducible metal oxide supports including CeO2, Nb2O5, and TiO2 thin films were prepared via sol-gel techniques. The structure, chemical state and optical property were characterized using XRD, XPS, TEM, SEM, and UV-VIS spectrometer. We found that the reducible metal oxide supports have a homogeneous thin thickness and crystalline structure after annealing at high temperature showing the different optical band gap energy. Langmuir-Blodgett technique and arc plasma deposition process were employed to ob-tain Pt nanoparticle arrays with capping and without capping layers, respectively on the oxide support to assess the role of the supports and capping layers on the catalytic activity of Pt catalysts under the CO oxidation. The catalytic performance of CO oxidation over Pt supported on metal oxide thin films under oxidizing reaction conditions (40 Torr CO and 100 Torr O2) was tested. The results show that the catalytic activity significantly depends on the metal oxide support and organic capping layers of Pt nanoparticles, revealing the strong metal-support interaction on these nanocatalysts systems.

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Status of Research on Selective Laser Sintering of Nanomaterials for Flexible Electronics Fabrication (나노물질의 선택적 레이저소결을 이용한 유연전기소자 구현 연구현황)

  • Ko, Seung-Hwan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.5
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    • pp.533-538
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    • 2011
  • A plastic-compatible low-temperature metal deposition and patterning process is essential for the fabrication of flexible electronics because they are usually built on a heat-sensitive flexible substrate, for example plastic, fabric, paper, or metal foil. There is considerable interest in solution-processible metal nanoparticle ink deposition and patterning by selective laser sintering. It provides flexible electronics fabrication without the use of conventional photolithography or vacuum deposition techniques. We summarize our recent progress on the selective laser sintering of metals and metal oxide nanoparticles on a polymer substrate to realize flexible electronics such as flexible displays and flexible solar cells. Future research directions are also discussed.

The Effect of Chemical Vapor Infiltrated SiC Whiskers on the Change in the Pore Structure of a Porous SiC Body

  • Joo, Byoung-In;Park, Won-Soon;Choi, Doo-Jin;Kim, Hai-Doo
    • Journal of the Korean Ceramic Society
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    • v.43 no.4 s.287
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    • pp.199-202
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    • 2006
  • In this study, SiC whiskers were grown on a porous SiC diesel particulate filter for nanoparticle filtering. To grow the whiskers at the inner pore without closing the pores, we used chemical vapor infiltration with a solution source and a dilute. As the deposition time increased, the whiskers grew and formed a network structure. After 180 min of deposition, the mean diameter of the whiskers was 174 nm and the compressive strength was 58.4 MPa. The pores shrank from $10{\mu}m\;to\;0.4{\mu}m$ and, because the whiskers filed the inner pores, the gradient of permeability decreased as the deposition time increased. However, by using the network structure of whiskers deposited for 120 min and 180 min, we obtained a diesel particulate filter with pores of $0.98{\mu}m\;and\;0.4{\mu}m$, respectively. Furthermore, the filter shows better permeability than a porous body with pores of $1{\mu}m$. In short, by filtering the nanoparticulate materials, the network structure of whiskers improves the strength, reduces the pore size and minimizes the permeability drop.

Binder-free Sn/Graphene Nanocomposites Prepared by Electrophoretic Deposition for Anode Materials in Lithium Ion Batteries

  • Bae, Eun Gyoung;Hwang, Yun-Hwa;Pyo, Myoungho
    • Bulletin of the Korean Chemical Society
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    • v.34 no.4
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    • pp.1199-1204
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    • 2013
  • Nanocomposites consisting of Sn nanoparticles and graphene oxide (GO) were electrophoretically deposited onto Cu current collectors that was used for anodes in Li ion batteries (LIBs). In order to optimize the electrochemical performance of nanocomposites as an anode material by controlling the oxygen functionality, the GO was subjected to $O_3$ treatment prior to electrophoretic deposition (EPD). During thermal reduction of the GO in the nanocomposites, the Sn nanoparticles were reduced in size, along with the formation of SnO and/or $SnO_2$ at a small fraction, relying on the oxygen functionalities of the GO. The variation in the duration of time for the $O_3$ irradiation resulted in a small change in total oxygen content, but in a significantly different fraction of each functional group in the GO, which influenced the Sn nanoparticle size and the amount of SnO (and/or $SnO_2$). As a result, the EPD films prepared with the GO that possessed the least amount of carboxylic groups (made by treating GO in an $O_3$ environment for 3 h) showed the best performance, when compared with the nanocomposites composed of untreated GO or GO that was $O_3$-treated for a duration of less than 3 h.