• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.3-4
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• 2007

Orientational ordering of polar molecules and excess charges at the interface are main origins of surface polarization. For organic electronics, probing and control of these two surface polarization phenomena are key issues. In this presentation, I report a novel electrical measurement that can directly probe orientational dipolar motion in surface monolayers by Maxwell-displacement-current, and also report a novel optical technique that allows carrier motions in organic materials by measuring the optical second harmonic signals activated by the electric field. Then I discuss how the control of dipolar motions and carrier motions are linked to organic electronics applications such as organic field effect transistors.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.26-26
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• 2011

Self-assembled monolayers (SAMs) prepared by sulfur-containing organic molecules on metal surfaces have drawn much attention for more than two decades because of their technological applications in wetting, chemical and biosensors, molecular recognition, nanolithography, and molecular electronics. In this talk, we will present self-assembly mechanism and two-dimensional (2D) structures of various organic thiol SAMs on Au(111), which are mainly demonstrated by molecular-scale scanning tunneling microscopy (STM) observation. In addition, we will provide some idea how to control 2D molecular arrangements of organic SAMs. For instance, the formation and surface structure of pentafluorobenzenethiols (PFBT) self-assembled monolayers (SAMs) on Au(111) formed from various experimental conditions were examined by means of STM. Although it is well known that PFBT molecules on metal surfaces do not form ordered SAMs, we clearly revealed for the first time that adsorption of PFBT on Au(111) at $75^{\circ}C$ for 2 h yields long-range, well-ordered self-assembled monolayers having a $(2{\times}5\sqrt{13})R30^{\circ}$ superlattice. Benzenethiols (BT) SAMs on gold usually have disordered phases, however, we have clearly demonstrated that the displacement of preadsorbed cyclohexanethiol self-assembled monolayers (SAMs) on Au(111) by BT molecules can be a successful approach to obtain BT SAMs with long-range ordered domains. Our results will provide new insight into controlling the structural order of BT or PFBT SAMs, which will be very useful in precisely tailoring the interface properties of metal surfaces in electronic devices.

• Genomics & Informatics
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• 제1권1호
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• pp.25-31
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• 2003

Local alignment is an important task in molecular biology to see if two sequences contain regions that are similar. The most popular approach to local alignment is the use of dynamic programming due to Smith and Waterman, but the alignment reported by the Smith-Waterman algorithm has some undesirable properties. The recent approach to fix these problems is to use the notion of normalized scores for local alignments by Arslan, Egecioglu and Pevzner. In this paper we consider the problem of finding all local alignments whose normalized scores are above a given threshold, and present a fast heuristic algorithm. Our algorithm is 180-330 times faster than Arslan et al.'s for sequences of length about 120 kbp and about 40-50 times faster for sequences of length about 30 kbp.

• 마이크로전자및패키징학회지
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• 제12권3호
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• pp.235-241
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• 2005

Incorporation of solid electrodes frequently involves plasma-based processing. The effect of plasma can influence the physical characteristics, depending on the magnitude in plasma. The undesired feature of plasma-induced damage should be prevented in characterizing the ultra-thin materials, such as ultra-thin films and organic monolayers. The current work at first proves the applicability of a liquid phase electrode in the electrical/dielectric properties through comparative work using Al and Hg on ultrathin $Al_2O_3$ films deposited through atomic layer deposition at low temperature: Two types of metals such as Aluminum (Al) and mercury (Hg) were used as electrodes in $Al_2O_3$ thin films in order to investigate the effect of electrode preparation on the current-voltage characteristics and impedance features as a function of thickness in $Al_2O_3$ film thickness. The success of Hg in $Al_2O_3$ thin films is applied to the AC and DC characterization of the organic monolayers obtained using the Langmuir-Blodgett method. From the DC current-voltage characteristics, the diode-like response is found to originate from the bulk response of the organic materials, evidenced by the fact and the capacitance is inversely related to the absolute thickness of organic layers.

• 전자공학회논문지D
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• 제34D권7호
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• pp.56-61
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• 1997

I $n_{0.53}$G $a_{0.47}$As/I $n_{0.52}$A $l_{0.48}$As pseudomorphic high electron mobility transistor (P-HEMT) structures were grown on semi-insulating InP substrates by molecular beam epitzxy method. The hall effect measuremetn was used to measure the electrical properties and the photoluminescence (PL) measurement was used to measure the electrical properties and the photoluminescence(PL) measurement for optical propety. By the cross-sectional transmission electron microscopy (XTEM) investigation of the V and X shape defects including slip with angle of 60.deg. C and 120.deg. C to surface in the sampel, the defects formation mecahnism in the I $n_{0.52}$A $l_{0.48}$As epilayers on InP substrates could be explained with the different thermal expansion coefficients between I $n_{0.52}$A $l_{0.48}$As epilayers and InP substrate.d InP substrate.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권2호
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• pp.87-91
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• 2000

Metal ion complex of poly(N-(2,4-imidazoly)ethyl)maleimide-alt-l-octadecene (IMO-O) polymer used to confirm the possibility of molecular device made by Langmuir-Blodgett(LB) method. Electrical properties of the metal ion complex LB film were investigated using Metal/Insulator/Metal(MIM) structure. In the surface pressure-area($\pi$-A) isotherm of IMI-O polymer, the surface pressure at collapse point has a difference due to the interaction between polymer and metal ions. And the complex between polymer and metal ions could be verified through the investigation by Raman spectroscopy. In the current-voltage(I-V) property, the conductivity change of IMO-O polymer complexes due to the kinds of metal of metal ions couldn't be observed. However, the limiting area of molecules was changed by the concentration of the metal ions and the conductivity was increased with the occupied molecular area.

• 전자공학회논문지A
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• 제32A권2호
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• pp.66-72
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• 1995

Using the Si/SiGe layer grown by solid source molecular beam epitaxy(SSMBE) on the LOCOS-patterned wafers, an emitter-base self-aligned hterojunction biplar transistor(HBT) with the polysilicon-emitter and the silicon germanium(SiGe) base has been fabricated. Trech isolation process, planarization process using a chemical-mechanical poliching, and the selectively implanted collector(SIC) process were performed. A titanium disilicide (TiSi$_{2}$), as a base electrode, was used to reduce an extrinsic base resistance. To prevent the strain relaxation of the SiGe epitaxial layer, low temperature (820${^\circ}C$) annealing process was applied for the emitter-base junction formation and the dopant activation in the arsenic-implanted polysilicon. For the self-aligned Si/SiGe HBT of 0.9${\times}3.8{\mu}m^{2}$ emitter size, a cut-off requency (f$_{T}$) of 17GHz, a maximum oscillation frequency (f$_{max}$) of 10GHz, a current gian (h$_{FE}$) of 140, and an emitter-collector breakdown voltage (BV$_{CEO}$) of 3.2V have been typically achieved.

• ETRI Journal
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• 제34권2호
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• pp.226-234
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• 2012

The novelty of this study resides in the fabrication of stoichiometric and stress-reduced $Si_3N_4/SiO_2/Si_3N_4$ triple-layer membrane sieves. The membrane sieves were designed to be very flat and thin, mechanically stress-reduced, and stable in their electrical and chemical properties. All insulating materials are deposited stoichiometrically by a low-pressure chemical vapor deposition system. The membranes with a thickness of 0.4 ${\mu}m$ have pores with a diameter of about 1 ${\mu}m$. The device is fabricated on a 6" silicon wafer with the semiconductor processes. We utilized the membrane sieves for plasma separations from human whole blood. To enhance the separation ability of blood plasma, an agarose gel matrix was attached to the membrane sieves. We could separate about 1 ${\mu}L$ of blood plasma from 5 ${\mu}L$ of human whole blood. Our device can be used in the cell-based biosensors or analysis systems in analytical chemistry.

• 전자공학회논문지D
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• 제35D권12호
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• pp.30-40
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• 1998

극 저 에너지 실리콘 이온 주입 시뮬레이션을 통하여 실리콘 내부에서 발생하는 격자 손상에 대하여 고전분자 동역학을 사용하여 시뮬레이션 하였다. 또한 최근에 개발된 EDIP 전위식이 실리콘 충돌 계산에 적합한지 여부를 분자 동역학을 사용하여 계산하였다. EDIP 전위식은 평형상태 계산에 알맞지만 충돌을 계산하는데는 적합하지 않았다. 또한 MDRANGE를 실리콘 공정에 맞도록 향상시켜 200eV, 500eV, 그리고 1000eV 에너지 붕소 이온 주입 시뮬레이션을 수행하여 실리콘 기판의 온도, 기울기 각도 및 에너지에 따른 붕소의 분포를 계산하였다. 1000eV 이하 에너지 붕소 이온 주입에서도 체널링 현상에 대한 고려가 필요하다는 것을 알 수 있었다.

• 대한전자공학회논문지SD
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• 제39권9호
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• pp.1-10
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• 2002

유기 발광 다이오드를 위한 indium oxide (ITO) 기판을 여러 가지로 방법으로 표면처리를 하고, 이에 따른 atomic force microscopy (AFM)에 의한 morphology의 변화와 표면에서 변화된 원소들의 조성비를 Auger electron spectroscopy (AES)분석에 의하여 조사하였다. 또한 이 기판을 사용하여 초고진공분자선 증착방법에 의하여 유기 발광다이오드를 제작하고 그 특성을 조사하였다. 그 결과 산소플라즈마으로 표면 처리한 ITO 기판 위에 제조된 organic light-emitting diode (OLED)소자의 특성이 향상되었다. 그것은 AES의 분석에 의하면 ITO 표면의 오염된 탄소가 제거되고 ITO의 일함수가 증가되어 정공이 유기물 층으로 용이하게 주입한 결과로 판단된다.