• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.2
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• pp.219-227
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• 2013

This paper reported a study on the thermal, mechanical and electrical insulation properties of epoxy/mica composites. To investigate the effect of mica content, glass transition temperature, mechanical properties such as tensile and flexural strength, and insulation breakdown properties for epoxy composites with various contents of mica. The effect of insulation thickness on insulation breakdown property was also studied. It was observed that tensile and flexural strength decreased with increasing mica content, while elastic modulus increased as the mica content increased. AC insulation breakdown strength for all epoxy/mica composites was higher than that of neat epoxy and that of the system with 20 wt% mica was 14.4% improved. As was expected, insulation breakdown strength at $30^{\circ}C$ was far higher than that at $130^{\circ}C$, and it was also found that insulation breakdown strength was inversely proportion to insulation thickness.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.5
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• pp.394-398
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• 2007

A simple doping method to fabricate a very thin channel body of the nano-scaled n-type fin field-effect-transistor (FinFET) by arsenic solid-Phase-diffusion (SPD) process is presented. Using the As-doped spin-on-glass films and the rapid thermal annealing for shallow junction, the n-type source-drain extensions with a three-dimensional structure of the FinFET devices were doped. The junction properties of arsenic doped regions were investigated by using the $n^+$-p junction diodes which showed excellent electrical characteristics. The n-type FinFET devices with a gate length of 20-100 nm were fabricated by As-SPD and revealed superior device scalability.

• Journal of the Korean Graphic Arts Communication Society
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• v.29 no.2
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• pp.1-13
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• 2011

The recent spotlight on electronic touch-screen display, a rapid breakthrough in the information society is evolving. Touch panel input device such as a keyboard or mouse without the use of, the on-screen character or a specific location or object on the person's hand touches a particular feature to identify the location of a panel is to be handled. The touch screen on the touch panel is used in the Ag paste is used mostly for low-curable paste. The thermal-curing paste according to the drying process of thermal energy consumption and improve the working environment of organic solvents have problems. In this study, Ag paste used in the non-thermal curing friendly and cost-effective UV curable paste was prepared. Current commercially available thermal-curable binder, was used instead of the flow characteristics of UV-curable oligomers and monomers with functional groups to give a single conductive Ag paste with the addition of a pattern could be formed. Ag paste as a result, thermal-curing adhesive, hardness, resistance and excellent reproduction of fine patterns and was available with screen printing environmentally friendly could see its potential as a patterning technology.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.284-287
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• 2017

This paper introduces liquid crystal (LC) alignment and its electro-optical properties in the LC cells with silver nanowire (AgNW) networks. The AgNW network was used as an electrode of LC cell as a substitute for an indium-tin-oxide (ITO) film. LC alignment characteristics in the LC cell using AgNW networks, which have two different sheet resistances of $60{\Omega}/m^2$ and $80{\Omega}/m^2$, were observed. The LC alignment characteristics including pretilt angle, LC alignment state, and thermal stability are similar irrespective of sheet resistance of AgNW network. However, twisted-nematic (TN)-LC cell normally operated when using AgNW network with sheet resistance of $80{\Omega}/m^2$. Electrooptical properties of TN-LC cell exhibited competitive performance compared to those of TN-LC cell based on conventional ITO electrode, which allow new approaches to replace conventional ITO electrode in display technology.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.11a
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• pp.75-79
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• 1993

The Thermally Stimulated Current(TSC) method has been allied to study the influence of the structural change and interface on the electrical properties of epoxy composites. Three DGBA- MeTHPA matrix model samples mixed different ratios arts silica(SiO$_2$) filled sample and silaln treating-filled sample have been studied. Above room temperature, the relaxation mode ${\alpha}$ peak associated with T$\_$g/ has been located at 110$^{\circ}C$. Below glass transition temperature(T$\_$g/), three relaxation modes are observed in all samples : a ${\beta}$ mode situated at 10$^{\circ}C$, a ${\gamma}$ mode located at -40$^{\circ}C$ and a $\delta$mode appeared in -120$^{\circ}C$, which may be due to segmental motion, side chains, substitution and terminal groups. The analysis of its fine structure indicates that constitution of elementary processes is characterized by the activation energy and relaxation time. Also the change of the molecular structure and their thermal motion are compared with the relaxation mode and conduction mechanism in TSC spectra through the dielectric properties and FTIR measurements.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.11
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• pp.896-900
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• 2010

Electrical properties of organic light-emitting diodes were studied in a device with 7,7,8,8-tetracyano-quinodimethane (TCNQ) to see how the TCNQ affects on the device performance. Since the TCNQ has a high electron affinity, it is used for a charge-transport and injection layer. We have made a reference device in a structure of ITO(170 nm)/TPD(40 nm)/$Alq_3$(60 nm)/LiF(0.5 nm)/Al(100 nm). And two types of devices were manufactured. One type of device is the one made by doping 5 and 10 vol% of TCNQ to N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine (TPD) layer. And the other type is the one made with TCNQ layer inserted in between the ITO anode and TPD organic layer. Organic layers were formed by thermal evaporation at a pressure of $10^{-6}$ torr. It was found that for the TCNQ doped devices, turn-on voltage of the device was reduced by about 20 % and the current efficiency was improved by about three times near 6 V. And for devices with TCNQ layer inserted in between the ITO anode and TPD layer, it was found that the current efficiency was improved by more than three times even though there was not much change in turn-on voltage.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.1010-1013
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• 2001

Zinc oxide(ZnO) films were prepared by ultrasonic spray pyrolysis on indium (In) films deposited by evaporation and subsequently submitted to rapid thermal annealing (RTA). The RTA was processed in air or a vacuum ambient. The crystallographic properties and surface morphologies of the films were characterized before and after the RTA by X-ray diffraction (XRD) and scanning electron microscopy(SEM), respectively. The resistivity variation of the films with RTA temperature and time was measured by the 4-point probe method. Auger electron spectroscopy(AES) was carried out to figure out the distribution of indium atoms in the ZnO films. The resistivity of the ZnO on In(ZnO/In) films decreased to 2${\times}$10$\^$-3/ $\Omega$cm by diffusion of the In. The In diffusion into the ZnO films roughened the surface of the ZnO films. The results of depth profile by AES showed a hump of In atoms around ZnO/In interface after the RTA at 800$^{\circ}C$, which disappeared by the RTA at 1000$^{\circ}C$. The effects of temperature, time and ambient during the RTA on the structural and electrical properties of the ZnO/In films were discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.5
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• pp.376-381
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• 2019

In this work, we evaluated the structural, electrical and optical properties of $Ge_8Sb_2Te_{11}$ and Cu-doped $Ge_8Sb_2Te_{11}$ thin films prepared by rf-magnetron reactive sputtering. The 200-nm-thick deposited films were annealed in a range of $100{\sim}400^{\circ}C$ using a furnace in an $N_2$ atmosphere. The amorphous-to-crystalline phase changes of the thin films were investigated by X-ray diffraction (XRD), UV-Vis-IR spectrophotometry, a 4-point probe, and a source meter. A one-step phase transformation from amorphous to face-centered-cubic (fcc) and an increase of the crystallization temperature ($T_c$) was observed in the Cu-doped film, which indicates an enhanced thermal stability in the amorphous state. The difference in the optical energy band gap ($E_{op}$) between the amorphous and crystalline phases was relatively large, approximately 0.38~0.41 eV, which is beneficial for reducing the noise in the memory devices. The sheet resistance($R_s$) of the amorphous phase in the Cu-doped film was about 1.5 orders larger than that in undoped film. A large $R_s$ in the amorphous phase will reduce the programming current in the memory device. An increase of threshold voltage ($V_{th}$) was seen in the Cu-doped film, which implied a high thermal efficiency. This suggests that the Cu-doped $Ge_8Sb_2Te_{11}$ thin film is a good candidate for PRAM.

• Transactions on Electrical and Electronic Materials
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• v.15 no.5
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• pp.265-269
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• 2014

Carbon nanofiber electrode has been fabricated for energy storage systems by the electrospinning of SU-8 precursor and subsequent pyrolysis. Various parameters including the applied voltage, the distance between syringe tip and target collector and the flow rate of the polymer affect the diameter of SU-8 electrospun nanofibers. Shrinkage during pyrolysis decreases the fiber diameter. As the pyrolysis temperature increases, the resistivity decreases dramatically. Low resistivity is one of the important characteristics of the electrodes of an energy storage device. Given the advantages of carbon nanofibers having high external surface area, electrical conductivity, and lithium intercalation ability, SU-8 derived carbon nanofibers were applied to the anode of a full lithium ion cell. In this paper, we studied the physical properties of carbon fiber electrode by scanning transmission microscopy, thermal gravimetric analysis, and four-point probe. The electrochemical characteristics of the electrode were investigated by cyclic voltammogram and electrochemical impedance spectroscopy plots.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.6
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• pp.460-465
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• 2001

(Ba$_{0.6-x}$Sr$_{0.4}$Ca$_{x}$)TiO$_3$(x=1.10,0.15,0.20) specimens were fabricated by the solid state reaction method and then the structural and dielectric properties as a function of he composition ratio and sintering temperature were studied. As a result of the differential thermal analysis(DTA), exothermic peak was observed at around 102$0^{\circ}C$ due to the formation of the polycrystalline perovskite phase. The BSCT(50/40/10) specimen sintered at 150$0^{\circ}C$ showed the highest average grain size(18.25${\mu}{\textrm}{m}$). The Curie temperature and dielectric constant at room temperature decreased with increasing Ca content. The dielectric constant and dielectric loss of the BSCT(50/40/10) specimen, sintered at 145$0^{\circ}C$, were about 4324 and 0.972% at 1KHz, respectively.ively.