• Journal of the Korean Vacuum Society
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• v.1 no.3
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• pp.346-352
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• 1992

반자성 반도체인 MnxCd1-xGa2Se4의 단결정을 조성비 ( $0leq$ $X \leq$ 1) 영역에서 TVTP(time-varying temperature profile)에 의한 화학수송법으로 성장하였다. 성장된 단결정 은 자연면을 갖은 경면으로 성장되었으며, X = 1.0 경우인 단결정의 크기는 12 $\times$ 6 $\times$ 1.5mm3이었다. MnxCd1-xGa2Se4의 결정구조는 defect chalcopyrite 구조이었으며, 조성비 X 가 증가함에 따라 격자상수 a는 선형적으로 감소하고, 격자상수 c는 증가하였다. 또한 distortion factor 2-(c/a)는 감소하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.123-126
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• 2004

We have demonstrated the fabrication of patterned 3D photonic crystals by holographic lithography in conjunction with soft lithography. Holographic lithography created 3D ordered macroporous structures and soft lithography made tailored defects. Because the hard baked photoresist pattern possessed high resistance against the uncured photoresist solution and the refractive index did not change appreciably by hard baking, a crosslinked photoresist was used as a relief pattern for the holographic fabrication of patterned 3D photonic crystals. More complicated defect geometries might be easily obtained with more complicated patterns on PDMS stamps. Moreover, the present results might be used as templates for 3D PCs of highindex defects that can be exploited as optical waveguides and optical circuits.

• Interaction and multiscale mechanics
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• v.4 no.2
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• pp.139-153
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• 2011

In this paper we develop a fully anisotropic pressure and temperature dependent model to investigate the effect of the microstructure on the shock response of ${\beta}$-HMX molecular single and polycrystals. This micromechanics-based model can account for crystal orientation as well as crystallographic twinning and slip during deformation and has been calibrated using existing gas gun data. We observe that due to the high degree of anisotropy of these polycrystals, certain orientations are more favorable for plastic deformation - and therefore defect and dislocation generation - than others. Loading along these directions results in highly localized deformation and temperature fields. This observation confirms that most of the temperature rise during high rates of loading is due to plastic deformation or dislocation pile up at microscale and not due to volumetric changes.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.5
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• pp.716-723
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• 1990

Transmission electron microscopy (TEM) and anger electron microscopy(AES) studies of GaAs/AlxGa1-xAs(x=0.58) quantum wells grown by low pressure metalorganic chemical vapor deposition(LP-MOCVD) are carried out. Isolated quantum well structure having the well width as small as 15 \ulcornerand multiquantum well structure, which consisted of 51 alternating layers with each thickness of 10\ulcorner were suscessfully grown. TEM analyses have shown that their interfaces were almost completely coherent without any structural disorder, alloy clustering and crystal defect. AES depth resolution have shown the compositional periodicity of superlattice structure.

• Journal of the Korean Ceramic Society
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• v.38 no.6
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• pp.499-505
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• 2001

The behaviour of ionic compound crystals under combined chemical and externally applied electrical potential gradients is discussed. Firstly, a systematic overview is given. Then a formal analysis follows. The transport equations of the ions and the electric defects predict that even with reversible electrodes demixing, and in particular decomposition of the compound will occur if the applied d.c. current density is sufficiently high. These predictions are illustrated by appropriate experiments. With the help of the solid solution (Me, Fe)O, where Fe-ions are the dilute species, we investigate experimentally the behaviour of a ternary ionic crystal under a d.c. electric current load. All the compounds were placed in a galvanic cell, and the internal reactions which then could be observed were driven by the electric field in this cell. In addition, we discuss the influence of the electric field on the classical solid state reaction AX+BX=ABX$_2$, if again the reaction couple is placed in a galvanic cell.

• Applied Microscopy
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• v.35 no.4
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• pp.64-73
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• 2005

In this paper we discussed in details how to determine the nature of dislocations in a crystal such as a Burgers vector, the line vector of dislocation and the associated slip plane, using LACBED and usual imaging techniques. These techniques basically involve the application of Cherns and Prestone s rules, the simulations of LACBED patterns with a certain form of the dynamical diffraction theory. The theoretical aspects including necessary approximations for calculations also were in details discussed. As a test specimen for experiments, the foils of a pure aluminum, containing many dislocations with appropriate density for LACBED experiments, were used..

• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.140-145
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• 2001

The tape carrier package(TCD) is one of the most important components in a liquid crystal display(LCD) module. It has a role to transmit electrical signals from a printed circular board(PCB) to a display panel. If TCP is damaged under mechanical shock, the signals can not be transmitted to the panel and as a result, some dead lines are generated on the panel. This kind of phenomenon is commonly called as 'line defects'. In this paper, new structural design concepts of TCP are proposed to guarantee its reliability by using Taguchi's approach and dynamic FE-analysis. The line defects problem of TCP module is solved by replacing the original TCP with the newly designed one.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.61-62
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• 2000

We have studied the molecular orientation by the phase transitions of the chiral smectic liquid crystals, 4-(1-Trifluoromethyl-6-ethoxy-hexyloxycarbonlphenyl)-4-nonyloxybiphenyl-4-carbo-xylate (R-TFMEOHPNBC) to seek the original solution of the zig-zag defect using two different experimental techniques; optical system and x-ray scattering. The phase sequence is gamma ferroelectric $(SmC{\gamma}\;^*)$ ${\rightarrow}$ smectic A (SmA) ${\rightarrow}$ isotropic (I). Existence of two layer spacing at chiral smectic phase gives a possibility of the molecular orientation in two different tilt angles, ${\theta}\;_1$ and ${\theta}\;_2$, which are separated each other to the layer normal at a given temperature. The gamma ferroelectric-like phase is, first, discovered in the single compound.

• Journal of the Semiconductor & Display Technology
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• v.16 no.1
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• pp.112-115
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• 2017

ITO thin films were grown on the glass substrate under various oxygen gas flow and substrate temperature by using FTS (Facing Target Sputtering) system. To investigate properties of as-prepared films for transparent electrical devices, we employed four-point probe, UV-VIS spectrometer, X-ray diffractometer (XRD), scanning electron microscopy (SEM), Hall Effect measurement system and Atomic Force Microscope (AFM). As a results, all of prepared samples has high transmittance of over 80 % in the visible range (300-800 nm). Their resistivity increased as a function of oxygen gas flow and substrate temperature due to their crystal structure and oxygen defect in the films. As-prepared films have a resistivity of under $10^{-4}({\Omega}-cm)$.

• Journal of the Korean institute of surface engineering
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• v.36 no.2
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• pp.141-147
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• 2003

Silicon carbide thin film was deposited in APCVD and LPCVD system with 1,3-DSB precursor 1,3-DSB is the single precursor to deposit SiC on Si at low temperature. SiC film was deposited at $850^{\circ}C$ lower than ordinary temperature ($1000~1200^{\circ}C$) in CVD process. SiC thin film glowed to high oriented (111) plane in APCVD system. In LPCVD system, SiC film groved to preferred (220) plane at same temperature. This discrepancy between preferred planes can be described by the difference of deposition mechanism. Amorphous phase and crystal defect were observed in APCVD system with the main growth mechanism of mass transport limited region. But in LPCVD system, we got the SIC film of uniform, faceted structure and high quality.