• 한국재료학회:학술대회논문집
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• 한국재료학회 1992년도 추계학술발표강연 및 논문개요집
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• pp.121-121
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• 1992

Deformation behavior of compatible polymer blends was studied using scanning electron, optical, and transmission electron microscopies. Four different compatible systems were employed and charaterized in this investigation : polystyrene(PS) and polyphenylene oxide(PPO), polystyrene(PS) and polyvinlmethylether(PVME), polystyrene(PS) and poly $\alpha$-methylstyrene(P$\alpha$MS). Individual craze and shear deformation zone microstructures were examined by transmission microscopy (TEM). For TEM observations, specimens deformed in-situ on a TEM grid were utilized. Quantiative analysis of these crazes and shear deformation zones was obtained from the nicrodensitometry of the TEM negatives in the manner developed by Lauterwasser and Kramer. Microdensitometry resulys showed that the fibril extension ratio decreased as the PPO content increased in the PS/PPO blends, and finally, for 100% PPO, only shear deformation zones were observed. For the PS/PVME blends, the ribril extension ratio also decreased as the VME content increased. For the PS/P$\alpha$MS blends, the fibril extension ratio increased as the P$\alpha$MS content increased, For the PPO/P$\alpha$MS blends, the fibril extension ratio increased as the P$\alpha$MS content increased.

• Applied Microscopy
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• 제36권spc1호
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• pp.35-40
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• 2006

Self-assembled InAs/GaAs quantum dots (QDs) were grown by the atomic layer epitaxy (ALE) and molecular beam epitaxy (MBE) techniques, The structure and the thermal stability of QDs have been studied by high resolution electron microscopy with in-situ heating experiment capability, The ALE and MBE QDs were found to form a hemispherical structure with side facets in the early stage of growth, Upon capping by GaAs layer, however, the apex of QDs changed to a flat one. The ALE QDs have larger size and more regular shape than those of MBE QDs. The QDs collapse due to elevated temperature was observed directly in atomic scale, In situ heating experiment within TEM revealed that the uncapped QDs remained stable up to $580^{\circ}C$, However, at temperature above $600^{\circ}C$, the QDs collapsed due to the diffusion and evaporation of In and As from the QDs, The density of the QDs decreased abruptly by this collapse and most of them disappeared at above $600^{\circ}C$.

• 전자공학회논문지A
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• 제31A권4호
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• pp.63-69
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• 1994

The Ultrahigh Vacuum Electron Cyclotron Resonance Chemical Vapor Deposition(UHV-ECRCVD) system whose base pressure is 1${\times}10^{9}$ torr has been constructed. In-situ cleaning prior to the epitaxial growth was carried out at 56$0^{\circ}C$ by ECR generated uniform hydrogen plasma whose density is $10^{10}/cm{3}$. The natural oxide was effectively removed without damage by applying positive DC bias(+10V) to the substrate. RHEED(Reflection High Energy Electron Diffraction) analysis has been used to confirm the removal of the surgace oxide and the streaky 2$\times$1 reconstruction of the Si surface, and the suppression of the substrate damage is anaylized by X-TEM(cross-sectional Transmission Electron Microscopy). Surface cleaning technique by ECR hydrogen plasma confirmed good quality epitaxial growth at low temperature.

• 한국전기전자재료학회논문지
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• 제32권1호
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• pp.64-69
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• 2019

Methylammonium lead triiodide ($MAPbI_3$)-based perovskite solar cells potentially have potential advantages such as high efficiency and low-cost manufacturing procedures. However, $MAPbI_3$ is structurally unstable and has low phase-change temperatures ($30^{\circ}C$ and $130^{\circ}C$); it is necessary to solve these problems. We investigated the crystal structure and phase separation using real-time temperature-change X-ray diffraction, transmission electron microscopy, and electron energy loss spectroscopy. $MAPbI_3$ has a tetragonal structure, and at about $35^{\circ}C$ the c-axis contracts, transforming $MAPbI_3$ into the related cubic crystal structure. In addition, at $130^{\circ}C$, phase separation occurs in which $CH_3NH_2$ and HI at the center of the unit cell of the perovskite structure are extracted by gas, leavingand only $PbI_2$ of the three-component structure, is produced as the final solid product.

• 한국진공학회지
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• 제19권1호
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• pp.14-21
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• 2010

Ge은 Si에 비하여 높은 이동도를 갖기 때문에 차세대 고속 metal oxide semiconductor field effect transistors (MOSFETs) 소자를 위한 channel 물질로서 각광받고 있다. 그러나 화학적으로 안정한 게이트 산화막의 부재는 MOS 소자에 Ge channel의 사용에 주요한 장애가 되어왔다. 특히, Ge 기판 위에 고품질의 계면 특성을 갖는 게이트 절연막의 제조는 필수 요구사항이다. 본 연구에서, $HfO_xN_y$ 박막은 Ge 기판 위에 플라즈마 원자층 증착법(plasma-enhanced atomic layer deposition, PEALD)을 이용하여 증착되었다. 플라즈마 원자층 증착공정 동안에 질소는 질소, 산소 혼합 플라즈마를 이용한 in situ 질화법에 의하여 첨가되었다. 산소 플라즈마에 대한 질소 플라즈마의 첨가로 성분비를 조절함으로써 전기적 특성과 계면 성질을 향상시키는데 초점을 맞추어서 연구를 진행하였다. 질소 산소의 비가 1：1이었을 때, EOT의 값의 10% 감소를 갖는 고품질의 소자특성을 보여주었다. X-ray photoemission spectroscopy (XPS)와 high resolution transmission electron microscopy (HR-TEM)를 사용하여 박막의 화학적 결합 구조와 미세구조를 분석하였다.

• Korea-Australia Rheology Journal
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• 제20권4호
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• pp.227-233
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• 2008

High impact polystyrene (HIPS)/organoclay nanocomposites via in situ polymerization were synthesized and their rheological properties were investigated. For the study, two types of organoclays were used: a commercially available organoclay, Cloisite 10A (C10A), and a laboratory-prepared organoclay having a reactant group, vinylclay (ODVC). The X-ray diffraction and transmission electron microscopy experiments revealed that the HIPS/ODVC nanocomposite achieved an exfoliated structure, whereas the HIPS/C10A nanocomposite achieved an intercalated structure. In the small-amplitude oscillatory shear experiments, both storage modulus and complex viscosity increased with increasing organoclay. A pronounced effect of the organoclay content was observed, resulting in larger storage modulus and stronger yield behavior in the low frequency region when compared to neat HIPS. The crossover frequencies associated with the inverse of a longest relaxation time decreased as the organoclay content increased. Over a certain value of ODVC content, a change of pattern in rheological properties could be found, indicating a solid-like response with storage modulus greater than loss modulus at all frequencies.

• Macromolecular Research
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• 제14권3호
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• pp.312-317
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• 2006

In the preparation of a polyacrylonitrile (PAN)/sodium montmorillonite (Na-MMT) nanocomposite via an in-situ polymerization method, macroazoinitiator (MAI) was intercalated in the gallery of Na-MMT to enhance the delamination of silicate layers by intergallery polymerization. The exfoliated fine dispersion observed by X-ray diffraction pattern and transmission electron microscopy, the enhanced tensile storage modulus and the thermal decomposition temperature showed that the intercalated MAI was effective in inducing intergallery polymerization and that a poly(ethylene glycol) block linked to a PAN block improved the dispersion of hydrophilic Na-MMT in the polymer matrix.

• 한국진공학회지
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• 제8권3B호
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• pp.283-289
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• 1999

Multilayer thin film reference materials for the sputter depth profiling analysis are used to calibrate the sputter depth scale by measuring the sputtering rate and to optimize the sputtering conditions for the best depth resolution. Surface analysis group of Korea Research Institute of Standards and science (KRISS) have developed various types of multilayer thin films by using an ion beam sputter deposition and in-situ surface analysis system. The chemical states of the thin films reference materials were certified by in-situ XPS and the thicknesses were certified by transmission electron microscopy (TEM).

• 한국진공학회지
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• 제10권1호
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• pp.22-26
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• 2001

Plasma assisted molecular beam epitaxy(PAMBE)를 사용하여 Si 기판위에 성장시킨 AlN 박막에 대하여 성장온도 및 기판의 방향성에 따른 박막의 결정성 변화를 분석하였다. Reflection high energy electron diffraction(RHEED) 패턴을 이용하여 성장 중의 결정성을 관찰하였고, 성장 후에는 X-ray diffraction(XRD), double crystal X-ray diffraction(DCXD), transmission electron microscopy/diffraction(TEM/TED)분석을 하였다. $850^{\circ}C$이상의 온도에서 Si(100)위에 성장된 AlN박막은 육방정계의 c축 방향으로 우선 배향되어 있음을 확인하였으며 Si(111)위에 성장된 AlN박막의 경우 AlN(0001)/Si(111), AlN(1100)/Si(110), AlN(1120)/Si(112)의 결정방위를 가지고 성장하였음을 확인하였다. 또한 Si(111) 기판 위에서는 전위와 적층결함 등 많은 결정결함에 의해 DCD패턴의 반치폭이 2$\theta$=$36.2^{\circ}$에서 약 3000arcsec에 이르는 등 결정성은 좋지 않았으나 AlN박막이 단결정으로 성장된 것으로 나타났다.

• Bulletin of the Korean Chemical Society
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• 제33권8호
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• pp.2535-2538
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• 2012

$SnO_2@carbon$ tube-core nanowire was synthesized via a facile self-organized method, which was in situ by one step via Chemical Vapor Deposition. The resulting composite was characterized by scanning electron microscopy, X-ray diffraction and transmission electron microscope. The diameter of the single nanowire is between 5 nm and 60 nm, while the length would be several tens to hundreds of micrometers. Then X-ray diffraction pattern shows that the composition is amorphous carbon and tin dioxide. Transmission electron microscope images indicate that the nanowire consists of two parts, the outer carbon tube and the inner tin dioxide core. Meanwhile, the possible growth mechanism of $SnO_2@carbon$ tube-core nanowire is also discussed.