• Title, Summary, Keyword: self-assembled monolayer

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Investigation of lubrication characteristics of self-assembled monolayer (자기 조립 분자막의 윤활 특성에 관한 연구)

  • 양지철;김대은
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.512-515
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    • 2002
  • The lubrication characteristics of SAM(self-assembled monolayer) have been investigated according to the change of surface group and surface temperature treatment with FDTS(1H, 1H, 2H, 2H-Perflurodecyltrichlorosilane) SAM and OTS(octadecyltrichlorosilane) SAM in micro scale. From the experimental results, it was found that OTS SAM gets destroyed at $200^{\circ}C$ and stiction and fiction coefficient increased, but FDTS SAM was stable up to $400^{\circ}C$. Also, it was found that the friction coefficient of normal OTS SAM is lower than that of FDTS SAM, but stiction is vice versa. This work shows the importance of surface group of self-assembled monolayer to control the lubrication characteristics and thermal stability.

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An Adsorption Process Study on the Self-Assembled Monolayer Formation of Octadecanethiol Chemisorged on Gold Surface

  • Kim, Dong Ho;No, Jae Gwon;Masahiko Hara;Lee, Hye Won
    • Bulletin of the Korean Chemical Society
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    • v.22 no.3
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    • pp.276-280
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    • 2001
  • The self-assembled formation of octadecanethiol (CH3(CH2)17SH) on a gold substrate was studied using a quartz crystal microbalance (QCM) and a scanning tunneling microscope (STM). From the QCM measurements at vario us concentrations of octadecanethiol solutions in hexane and alcohol, the adsorption process of octadecanethiol onto Au was confirmed to consist of two steps as follows: (i) fast but disordered adsorption and (ii) a thermodynamically controlled rearrangement for uniform packing of octadecanethiol. Also, it was revealed that the adsorption rate became faster in ethanol than in hexane since less solubility of octadecanethiol in ethanol could help the formation of the monolayers. At 5 ${\times}$10-7 M solution, the monolayer formation was monitored by STM. The morphology of monolayer region was initially circular (diameter size: 7.26 $\pm$ 2.1 nm) and gradually changed to a stripe type after several minutes. At higher concentration, the self-assembled monolayer was formed immediately after the solution was introduced to a substrate.

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Work Function Increase of ITO Modified by Self Assembled Monolayer for Organic Electrical Devices (유기 디스플레이 소자를 위한 Self Assembled Monolayer의 표면개질을 이용한 ITO의 일함수 증가)

  • Jee Seung-Hyun;Kim Soo-Ho;Ko Jae-Hwan;Yoon Young-Soo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.6
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    • pp.563-567
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    • 2006
  • Indium tin oxide (ITO) used as an electrode in organic light emitting diodes (OLEDs) and organic thin film transistors (OTFTs) was modified by a self-assembled monolayer (SAM). For device fabrication, surface of the ITO was modified by immersion in a solution including various phosphonic acid at room temperature in order to increase work function of an electrode. The work function of ITO with SAM was measured by Kelvin probe. Work function increase of 0.88 eV was observed in ITO with various SAM. Therefore, ohmic contact is achieved in an interface between ITO and organic semiconductors (pentacene). We analyzed the origin of work function increase of ITO with SAM by X-ray photoelectron spectroscopy. We confirmed that increase of oxygen bonding energy attributed to increase the work function of ITO. These results suggested that ITO with the SAM gives a high possibility for high performance of OLEDS and OTFTs.

Development of Highly Conductive Poly(3,4-ethylenedioxythiophene) Thin Film using High Quality 3-Aminopropyltriethoxysilane Self-Assembled Monolayer (고품질 3-Aminopropyltriethoxysilane 자기조립단분자막을 이용한 고전도도 Poly(3,4-ethylenedioxythiophene) 전극박막의 개발)

  • Choi, Sangil;Kim, Wondae;Kim, Sungsoo
    • Journal of the Chosun Natural Science
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    • v.4 no.4
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    • pp.294-297
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    • 2011
  • Quality of PEDOT electrode thin film vapor phase-polymerized on 3-aminopropyltriethoxysilane (APS) self-assembled monolayer (SAM) is very crucial for making an ohmic contact between electrode and semiconductor layer of an organic transistor. In order to improve the quality of PEDOT film, the quality of APS-SAM laying underneath the film must be in the best condition. In this study, in order to improve the quality of APS-SAM, the monolayer was self-assembled on $SiO_2$ surface by a dip-coating method under strictly controlled relative humidity (< 18%RH). The quality of APS-SAM and PEDOT thin film were investigated with a contact angle analyzer, AFM, FE-SEM, and four-point probe. The investigation showed that a PEDOT film grown on the humidity-controlled SAM is very smooth and compact (sheet resistivity = 20.2 Ohm/sq) while a film grown under the uncontrolled condition is nearly amorphous and contains quite many pores (sheet resistivity = 200 Ohm/sq). Therefore, this study clearly proves that a highly improved quality of APSSAM can offer a highly conductive PEDOT electrode thin film on it.

Pd Seed Layer for Electroless Cu Deposition on TaN Diffusion Barrier by Self-Assembled-Monolayer Method(SAM) (Self assembled-monolayer(SAM)법을 이용한 TaN 확산방지막의 무전해 Cu 도금용 Pd seed layer 제조 및 특성)

  • Han, Won-Kyu;Cho, Jin-Ki;Choi, Jae-Woong;Kim, Jeong-Tae;Yeom, Seung-Jin;Kwak, Noh-Jung;Kim, Jin-Woong;Kang, Sung-Goon
    • Korean Journal of Materials Research
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    • v.17 no.9
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    • pp.469-474
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    • 2007
  • Electroless deposition(ELD) was applied to fabricate Cu interconnections on a TaN diffusion barrier with Pd seed layer. The Pd seed layer was obtained by self-assembled monolayer method(SAM) with PDDA and PSS as surfactants. We were able to obtain about 10nm Pd nano particles as seeds for electroless Cu deposition and the density of Pd seeds was much higher than that of Pd seeds fabricated by conventional Pd sensitization-activation method. Also we were able to obtain finer Cu interconnections by ELD. Therefore we concluded that the Pd seed layer by SAM was able to be applied to form Cu interconnection by ELD for under 30nm feature.

Superb Mechanical Stability of n-Octadecyltriethoxysilane Monolayer Due to Direct Chemical Bonds between Silane Headgroups and Mica Surface: Part II

  • Kim, Sungsoo
    • Journal of the Chosun Natural Science
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    • v.3 no.2
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    • pp.96-102
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    • 2010
  • It is still controversial where the improved stability of n-octadecyltriethoxysilane self-assembled monolayer (OTE SAM) on plasma-pretreated mica surface exactly originates from. To date, it has been well known that the extensive cross-polymerization between silane headgroups is a crucial factor for the outstanding mechanical strength of the monolayer. However, this study directly observed that the stability comes not only from the cross-links but also, far more importantly, from the direct chemical bonds between silane headgroups and mica surface. To observe this phenomenon, n-octadecyltrichlorosilane monolayers were self-assembled on both untreated and plasma treated mica surfaces, and their adhesion properties at various stress conditions and force profiles in pure water were investigated and compared through the use of the surface forces apparatus technique. It revealed that, in pure water, there is a substantial difference of stability between untreated and plasma treated cases and the plasma treated surface is mechanically much more stable. In particular, the protrusion behavior of the monolayer during contact repetition experiment was always observed in the untreated case, but never in the plasma treated case. It directly demonstrates that the extensive chemical bonds indeed exist between silane head-groups and plasma treated mica surface and dramatically improve the mechanical stability of the OTE monolayer-coated mica substrate.

Random Walk Simulation for the Growth of Monolayer in Dip Pen Nanolithography

  • Kim, Hyojeong;Ha, Soojung;Jang, Joonkyung
    • Bulletin of the Korean Chemical Society
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    • v.34 no.1
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    • pp.164-166
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    • 2013
  • Using a simple random walk model, this study simulated the growth of a self-assembled monolayer (SAM) pattern generated by dip-pen nanolithography (DPN). In this model, the SAM pattern grew mainly via the serial pushing of molecules deposited from the tip. This study examined various SAM patterns, such as lines, crosses and letters, by changing the tip scan speed.

Tribological Characteristics of FDTS & OTS SAM according to Annealing Temperature (FDTS와 OTS SAM의 어닐링 온도에 따른 트라이볼로지 특성)

  • 양지철;김대은
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.1
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    • pp.240-247
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    • 2003
  • The tribological characteristics of FDTS (1H, 1H, 2H, 2H-Perflurodecyltrichlorosilane) SAM (self-assembled monolayer) and OTS (octadecyltrichlorosilane) SAM treated by high temperature annealing have been investigated from the viewpoint of stiction, adhesion and friction in micro/nano scale. From the experimental results, it was found that OTS SAM gets destroyed at 20$0^{\circ}C$ and stiction, adhesion and friction coefficient increased, but FDTS SAM was stable up to 40$0^{\circ}C$. Also, it was found that the friction coefficient of normal OTS SAM below 20$0^{\circ}C$ is lower than that of FDTS SAM in micro/nano scale, but stiction and adhesion is vice versa. This work shows the importance of surface group of self-assembled monolayer in dictating the tribological characteristics and thermal stability.