• Macromolecular Research
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• 제12권6호
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• pp.564-572
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• 2004

Modem applications could benefit from multifunctional materials having anisotropic optical, electrical, thermal, or mechanical properties, especially when coupled with locally controlled distribution of the directional response. Such materials are difficult to engineer by conventional methods, but the electric field-aided technology presented herein is able to locally tailor electroactive composites. Applying an electric field to a polymer in its liquid state allows the orientation of chain- or fiber-like inclusions or phases from what was originally an isotropic material. Such composites can be formed from liquid solutions, melts, or mixtures of pre-polymers and cross-linking agents. Upon curing, a 'created composite' results; it consists of these 'pseudofibers' embedded in a matrix. One can also create oriented composites from embedded spheres, flakes, or fiber-like shapes in a liquid plastic. Orientation of the externally applied electric field defines the orientation of the field-aided self-assembled composites. The strength and duration of exposure of the electric field control the degree of anisotropy created. Results of electromechanical testing of these modified materials, which are relevant to sensing and actuation applications, are presented. The materials' micro/nanostructures were analyzed using microscopy and X-ray diffraction techniques.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.309-312
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• 2004

The electronic structure of ZnO oxide semiconductor having high optical transparency and good electric conductivity was theoretically investigated by $DV-X_{\alpha}$(the discrete variation $X_{\alpha}$) method, which is a sort of the first principle molecular orbital method using Hatre-Fock-Slater approximation. The electrical and optical properties of ZnO are seriously affected by the addition of impurities. The imnurities are added to ZnO in order to increase the electric conductivity of an electrode without losing optical transparency. In this study, the effect of impurities of III and IV family on the band structure, impurity levels and the density of state of ZnO were investigated. The cluster model used for calculations was $[MZn_{50}O_{53}]^{-2}$(M=elements belonging to III and IV family).

• Bulletin of the Korean Chemical Society
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• 제24권6호
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• pp.780-784
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• 2003

The collective electronic oscillator (CEO) method was developed by Mukamel and collaborators.[Phys. Rev. Lett. 1992, 69, 65; Science 1997, 277, 781] Recently Ⅰ have extended the CEO method to obtain the frequency dependent optical properties with all the contributing components. The brief introduction of the CEO fomalism and its recent applications to linear absorption and two-photon absorption (TPA) of conjugated organic molecules will be discussed. The size scaling of optical properties of polyenes and polyynes have studied by ab initio calculations, and this result is consistent with the coherence length of the time dependent densities to first ($ρ^(1)$) and second order ($ρ^(2)$) in the electric field obtained from the CEO method.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.114-114
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• 2003

SiC is promising materials because of its typical properties. So, SiC nanowires and rods were fabricated using various methods. Among theses methods, CVD was a effective method to growth SiC nanowire on the Si for using optical and electrical devices. SiC nanowires were synthesized by CVD using single precursors on Si substrate. To growth SiC nanowire, various metal used to catalyst. Catalyst affects rnicrostructures and growth conditions. Electric and optical properties were varied with kind of catalyst. Difference of these characteristics was due to the reactivity of catalyst and stability of growth process

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.525-528
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• 2001

ZnO:Al thin film can be used as a transparent conducting oxide(TCO) which has low electric resistivity and high optical transmittance for the front electrode of amorphous silicon solar cells and display devices. This study of electrical, crystallographic and optical properties of Al doped ZnO thin films prepared by Facing Targets Sputtering (FTS), where strong internal magnets were contained in target holders to confine the plasma between the targets, is described. Optimal transmittance and resistivity was obtained by controlling flow rate of O$_2$ gas and substrate temperature. When the of gas rate of 0.3 and substrate temperature 200$^{\circ}C$ , ZnO:Al thin film had strongly oriented c-axis and lower resistivity(<10$\^$-4/Ω-cm).

• 반도체디스플레이기술학회지
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• 제4권4호
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• pp.5-8
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• 2005

In this study, we prepared the ITO thin film for TOLED(Top-emitting OLED) or flexible display at room temperature using the FTS(Facing Targets Sputtering Apparatus). We observed characteristics of deposited thin films as a function of sputtering conditions. XRD patterns were independence trom oxygen gas flow and input current. But electrical and optical properties were strongly dependence. In the results, we could prepare good properties of ITO thin films resistivity of $4.27X10^{-4}[\Omega-cm]$, transmittance of over 80% at working gas pressure 1[mTorr], input current 0.6[A], oxygen gas ratio 0.3[sccm], at room temperature.

• Carbon letters
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• 제1권2호
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• pp.76-81
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• 2000

Physical properties of artificial graphite electrodes were evaluated along three different directions; circumferential (X), radial (Y), and axial (Z) directions. Four kinds of commercial electrode products were used in this study for the evaluation; pole (AP) and nipple (AN) of manufacturer A, pole (BP) and nipple (BN) of manufacturer B. The mechanical, electrical, and thermal properties in X and Y directions were very similar to each other. In Z direction, however, the mechanical properties, including flexural strength and compressive strength, were higher, and electric resistance and thermal expansion were much lower than those in the other directions. The microstructures observed by optical microscope and scanning electron microscope revealed that the differences in properties by the measuring direction were caused by the preferential alignment of needle cokes along the Z direction. When comparing the properties of the electrode samples in the same direction, the mechanical properties mainly depended on the bulk density or porosity of the samples as well as preferential alignment of needle cokes.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.327-330
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• 2000

The scanning Maxwell-stress microscopy (SMM) is a dynamic noncontact electric force microscopy that allows simultaneous access to the electrical properties of molecular system such as surface potential, surface charge, dielectric constant and conductivity along with the topography. The Scanning near-field optical / atomic force microscopy (SNOAM) is a new tool for surface imaging which was introduced as one application of the atomic force microscope (AFM). Operated with non-contact forces between the optical fiber and sample as well as equipped with the piezoscanners, the instrument reports on surface topology without damaging or modifying the surface for measuring of optical characteristic in the films. We report our recent results of its application to nanoscopic study of domain structures and electrical functionality in organic thin films by SMM. Furthermore, we have illustrated the SNOAM image in obtaining the merocyanine dye films as well as the optical image.

• 전기학회논문지
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• 제65권12호
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• pp.2014-2018
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• 2016

Transparent, conductive electrode films, showing the particular characteristics of good conductivity and high transparency, are of considerable research interest because of their potential for use in opto-electronic applications, such as smart window, photovoltaic cells and flat panel displays. Multilayer transparent electrodes, having a much lower electrical resistance than widely-used transparent conducting oxide electrodes, were prepared by using RF/DC magnetron sputtering system. The multilayer structure consisted of three layers, [NiInZnO(NIZO)/Ag/NIZO]. The optical and electrical properties of the multilayered NIZO/Ag/NIZO structure were investigated in relation to the thickness of each layer. The optical and electrical characteristics of multilayer structures have been investigated as a function of the Ag and NIZO film thickness. High-quality transparent conductive films have been obtained, with sheet resistance of $9.8{\Omega}/sq$ for Ag film thickness of 8 nm. Also the multilayer films of inserted Ag 8 nm thickness showed a high optical transmittance above 93% in the visible range. The electrical and optical properties of the new multilayer films were mainly dependent on the thickness of Ag insertion layer.

• 한국전기전자재료학회논문지
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• 제19권10호
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• pp.901-906
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• 2006

The transparent conductive oxide(TCO) has been used in necessity as front electrode for increasing efficiency of LED. In our paper, aluminium-doped zinc oxide films(AZO), which has transparent conducting were prepared with RF magnetron sputtering system on glass substrate(corning 1737) and annealed at $400^{\circ}C$ for 2 hr in vacuum ambient and $600^{\circ}C$ for 2hr with $O_2$ ambient respectively. The smooth AZO films were etched in diluted HCL(0.5 %) to examine the surface properties, which in ambient post-annealing process. We confirmed that the electric, structural and optical properties of textured AZO thin films, which implemented using the methods of XRD, FWHM, AFM and Hall measurement. The properties of textured AZO thin films especially depended on the ambient post-annealing process. We presumed that the change of transmittances as R G B LED and the ambient post-annealing process will be increasing the efficiency of LED.