• 제목/요약/키워드: Roughening transition

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Roughening Transition of Crystals - Classical Thermodynamic Approach

  • Jo, Wook;Hwang, Nong-Moon;Kim, Doh-Yeon
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.60-61
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    • 2006
  • In this contribution, we attempted a theoretical analysis on the validity of the widely-accepted idea that rough and singular surfaces can coexist in a crystal at equilibrium. By manipulating the Cahn and Hoffman capillarity vector, the conclusion that a crystal at equilibrium should be composed either of singular surfaces or of rough ones was reached.

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열 CVD법으로 증착된 SnO2 박막의 미세구조와 전기적 특성 (Microstructure and Electrical Properties of SnO2 Thin Films Grown by Thermal CVD Method)

  • 정진;최승평;신동찬;구재본;송호준;박진성
    • 한국전기전자재료학회논문지
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    • 제16권5호
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    • pp.441-447
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    • 2003
  • When a SnO$_2$ thin film was deposited by thermal CVD, two different types of growth behavior that were dependent on the deposition temperature were observed. The film grown at 475$^{\circ}C$ had a wide grain size distribution and a faceted surface shape. On the other hand, the film grown at 5$25^{\circ}C$ had a relatively narrow grain size distribution and a rounded sulfate shape. The aspects of grain shape and growth behavior agree well with the theory of gram growth and a roughening transition. The charge tarrier density decreased with deposition time. According to photoluminescence measurements, the peak intensity of the spectra occurred at approximately 2.5 eV, which is related to oxygen vacancies, and decreased with increasing of deposition time. These measurement results suggest that the number of oxygen vacancies, which is related to the electrical conductivity, decrease with deposition time.

The Influence of Solvent & Impurity on the Crystal growth of Urea: A Molecular Dynamics and Monte Carlo study

  • 이태범;강진구;최청송
    • 한국결정성장학회:학술대회논문집
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    • 한국결정성장학회 1997년도 Proceedings of the 13th KACG Technical Meeting `97 Industrial Crystallization Symposium(ICS)-Doosan Resort, Chunchon, October 30-31, 1997
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    • pp.105-109
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    • 1997
  • 요소결정성장에 용매와 불순물이 주는 영향을 Monte Carlo법과 분자동역학법을 통해 분석하였으며 이를 통해 불순물인 Biuret이 결정의 Morphology에 대한 영향뿐만 아니라 내부격자에 용매인 물을 흡착시킨다는 것을 확인하였다. 또한 계면의 용매, 용질 그리고 격자층의 확산계수를 분석한 결과 용매인 물이 "Roughening Transition" 메커니즘으로 결정성장에 영향을 준다는 것을 밝혔다.다는 것을 밝혔다.

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Mechanism for Shape Control of Cu Nanocrystals Prepared by Polyol Process

  • Cha, Seung-I.;Kim, Kyung-T.;Mo, Chan-B.;Jeong, Yong-J.;Hong, Soon-H.
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.154-155
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    • 2006
  • This study investigated a mechanism for controlling the shape of Cu nanocrystals fabricated using the polyol process, which considers the thermodynamic transition from a facetted surface to a rough surface and the growth mechanisms of nanocrystals with facetted or rough surfaces. The facetted surfaces were stable at relatively low temperatures due to the low entropy of perfectly facetted surfaces. Nanocrystals fabricated using a coordinative surfactant stabilized the facetted surface at a higher temperature than those fabricated using a non-coordinative surfactant. The growth rate of the surface under a given driving force was dependent on the surface structure, i.e., facetted or rough, and the growth of a facetted surface was a thermally activated process. Surface twins decreased the activation energy for growth of the facetted surface and resulted in rod- or wire-shaped nanocrystals

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