• Title/Summary/Keyword: SAMs

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Influence of Surface Morphology and Substrate on Thermal Stability and Desorption Behavior of Octanethiol Self-Assembled Monolayers

  • Ito, Eisuke;Gang, Hun-Gu;Ito, Hiromi;Hara, Masahiko;No, Jae-Geun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.219-219
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    • 2012
  • The formation and thermal desorption behaviors of octanethiol (OT) SAMs on single crystalline Au (111) and polycrystalline Au, Ag, and Cu substrates were examined by X-ray photoelectron microscopy (XPS), thermal desorption spectroscopy (TDS), and contact angle (CA) measurements. XPS and CA measurements revealed that the adsorption of octanethiol (OT) molecules on these metals led to the formation of chemisorbed self-assembled monolayers (SAMs). Three main desorption fragments for dioctyl disulfide (C8SSC8+, dimer), octanethiolate (C8S+), and octanethiol (C8SH+) were monitored using TDS to understand the effects of surface morphology and the nature of metal substrates on the thermal desorption behavior of alkanethiols. TDS measurements showed that a sharp dimer peak with a very strong intensity on single crystalline Au (111) surface was dominantly observed at 370 K, whereas a broad peak on the polycrystalline Au surface was observed at 405 K. On the other hand, desorption behaviors of octanethiolates and octanethiols were quite similar. We concluded that substrate morphology strongly affects the dimerization process of alkanethiolates on Au surfaces. We also found that desorption intensity of the dimer is in the order of Au>>Ag>Cu, suggesting that the dimerization process occurs efficiently when the sulfur-metal bond has a more covalent character (Au) rather than an ionic character (Ag and Cu).

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An Evaluation Method of Water Supply Reliability for Dams by Firm Yield Analysis (보장 공급량 분석에 의한 댐의 물 공급 안전도 평가기법 연구)

  • Lee, Sang-Ho;Kang, Tae-Uk;Jung, Eui-Taek
    • Proceedings of the Korea Water Resources Association Conference
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    • 2005.05b
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    • pp.294-298
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    • 2005
  • 신뢰도를 이용하여 댐의 물 공급 안전도를 정의하였다. 그리고 보장 공급량 분석에 의한 댐의 물 공급 안전도 평가 절차를 제안하였고, 소양강댐과 충주댐의 물 공급 안전도를 평가하였다. 여러 묶음의 월 유출 시계열을 모의발생시키기 위하여 SAMS-2000을 사용하였고, 보장공급량 결정을 위한 저수지 모의운영에는 HEC-5가 사용되었다. 50년 계획 기간에 대하여 설계 유출자료에 의한 소양강댐 보장 공급량의 물 공급 안전도는 $80.5\%$로 평가되었고, 준공 후 기록 유입량에 의한 보장 공급량의 물 공급 안전도는 $53.7\%$였다. 기록 유입량 자료의 보장 공급량(15.85억 $M^3/yr$)을 계획 공급량으로 하면 연간 0.94억 $m^3 $의 용수를 추가 공급할 수 있다. 충주댐의 설계 유출자료에 의한 보장 공급량 34.22억 $M^3/yr$를 계획 공급량으로 하면 모든 시계열에 대하여 반드시 물 부족이 발생하였다. 이는 설계 당시 유입량의 과대평가에 기인한다. 제안된 절차를 적용하면 보다 객관적으로 댐의 물 공급 안전도를 평가할 수 있다.

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Fabrication of Au(111) substrate and tunneling current characteristics of self-assembled Viologen molecule (Au(111) 기판 제작과 자기조립된 Viologen 분자의 tunneling current 특성)

  • Lee, Nam-Suk;Choi, Won-Suk;Qian, Dong-Jin;Kwon, Young-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.255-256
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    • 2006
  • The electrical properties of viologen ($VC_8SH$) were studied in terms of the tunneling current characteristics using self-assembling techniques and ultra high vacuum scanning tunneling microscopy (UHV-STM). We fabricated the Au substrate were deposited by thermal evaporation system($420^{\circ}C$). Self-assembled monolayers (SAMs) were prepared on Au(111), which had been thermally deposited onto freshly cleaved, heated mica. The Au substrate was exposed to a 1 mM/L solution of Octanethiol in ethanol for 24 h to form a monolayer. After through rinsing the sample, it was exposed to a 0.1 mM/L solution of $VC_8SH$ in ethanol for 30 min. We measurement of the morphology on the single viologen molecule. The current-voltage (I-V) properties were measured at arbitary configured points on the surface of the sample by using a STS.

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Fabrication of metal structure using AI sacrificial layer (알루미늄 희생층을 이용한 금속 구조물의 제작)

  • Kim, Jung-Mu;Park, Jae-Hyoung;Lee, Sang-Ho;Sin, Dong-Sik;Kim, Yong-Kweon;Lee, Yoon-Sik
    • Proceedings of the KIEE Conference
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    • 2001.07c
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    • pp.1893-1895
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    • 2001
  • In this paper, novel release technique using wet etch is proposed. The results of this technique and the results of SAMs (Self-Assembled monolayers) coated after release using this technique are compared. Fabricated structure have 100 um in width and experimental length is from 100 um to 1 mm. Thickness of aluminum sacrificial layer is 2 um and structure thickness is 2.5 um. Cantilevers and bridges are fabricated with electroplated gold and silicon nitride deposited on substrate. An aluminium sacrificial layer was evaporated thermally and removed in various wet etching solutions. Detachment length of cantilever is 200 um and detachment length of bridge is 1 mm after isooctane rinsing. And the SAMs coating condition which is appropriate for gold and nitride are studied respectively.

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