• Journal of the Korean Electrochemical Society
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• v.27 no.3
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• pp.97-104
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• 2024

The electrodes of commercialized lithium secondary batteries are manufactured through a wet coating process, and the drying process (DC) is a very important factor as to electrode production speed and process cost. In this study, silicon anodes were manufactured under high-temperature (180 ℃) and low-temperature (50 ℃) DC to investigate the quality and the electrochemical performance of Si-electrodes according to DC. High-temperature DC can quickly evaporate the solvent in the Si-electrode slurry, improving the electrode production rate. However, this also causes the electrode composite to peel off from the current collector. As a result, the Si-electrode's adhesion weakened, and the electrode coating's quality deteriorated. In addition, the Si-electrode manufactured under high-temperature was found to have a thicker composite material than the Si-electrode manufactured under low-temperature. Si-electrodes manufactured under high-temperature had higher sheet resistance and lower electrical conductivity than those manufactured under low-temperature. Consequently, the Si-electrode manufactured under low-temperature showed 152.5% superior cycle performance compared to the Si-electrode manufactured under high-temperature. (Discharge capacities of Si-electrodes manufactured under high-temperature and low-temperature DC were 844 and 1287 mAh g^-1, respectively, after 300 cycles). Establishing the DC of Si-electrodes can easily provide new perspectives to improve the quality and stability of Si-electrodes.

• Journal of the Korean Electrochemical Society
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• v.22 no.4
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• pp.155-163
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• 2019

Mixture electrodes of a graphite having a good cycle performance and a silicon monoxide (SiO) having a high capacity are fabricated and their cycle performances are evaluated as negative electrodes for lithium-ion batteries. The electrode prepared by mixing the natural graphite and carbon-coated SiO in a mass ratio of 9:1 shows a reversible capacity of $480mAh\;g^{-1}$, 33% higher than that of graphite. However, the capacity deteriorates continuously upon cycling due to the volume change of silicon monoxide. In this study, the factors that can improve the cycle performance have been discussed through the change in the configurations of the electrode and the electrolyte. The electrode using the carboxymethyl cellulose (CMC) binder shows the best cycle performance compared to the conventional binders. The electrode sing the CMC and styrene-butadiene rubber (SBR) binder not only has almost the similar cycle characteristics with the electrode using the CMC binder but also has the better rate capability. When the fluoroethylene carbonate (FEC) is used as an electrolyte additive, the cycle life is improved. However, the electrolyte with 5 wt% of FEC is appropriate because the rate capability decreases when the content of FEC is increased to 10 wt%. In addition, when the mass loading of the electrode is lowered, the cycle performance is greatly improved. Also, enhanced cycle performance is achieved using the roughened Cu current collector polished by abrasive paper.

• Applied Chemistry for Engineering
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• v.20 no.1
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• pp.99-103
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• 2009

HBr and $O_2$ in $Cl_2$ gas ambient for the high density plasma gate etching has been used to increase the performance of gate electrode in semiconductor devices. When an un-doped amorphous silicon layer was used for a gate electrode material, the notching profile was observed at the outer sidewall foot of the outermost line. This phenomenon can be explained by the electron shading effect: i.e., electrons are captured at the photoresist sidewall while ions pass through the photoresist sidewall and reach the oxide surface at a narrowly spaced pattern during the over etch step. The potential distribution between gate lines deflects the ions trajectory toward the gate sidewall. In this study, an appropriate mechanism was proposed to explain the occurrence of notching in the gate electrode of un-doped amorphous silicon.

• Journal of the Korean Electrochemical Society
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• v.10 no.2
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• pp.104-109
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• 2007

Single fuel cell was fabricated with a MEA (membrane electrode assembly) that had a $4cm^2$ active area and with silicon bipolar plates those were introduced to miniaturize the fuel cell by replacing heavy weight graphite plates. Optimum humidification condition for the single cell was selected based on performance results obtained varying humidifier temperature at a fixed feed rate of hydrogen and oxygen. Furthermore, to study the effect of humidification condition on the performance of a fuel cell stack, the fuel cell stack consisting of two MEAs and silicon bipolar plates was studied, then problems and characteristics of silicon-based fuel cell stack were examined.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.1035-1038
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• 2002

The electrical properties of Porous polycrystalline silicon Nano-Structure (PNS) as a cold cathode were investigated as a function of anodizing condition, the thickness of Au film as a top electrode and the substrate temperature. Non-doped 2${\mu}m$-polycrystalline silicon was electrochemically anodized in HF: ethanol (=1:1) mixture as a function of the anodizing condition including a current density and anodizing time. After anodizing, the PNS was thermally oxidized for 1 hr at 900 $^{\circ}C$. Then, 20nm, 30nm, 45nm thickness of Au films as a top electrode were deposited by E-beam evaporator. Among the PNSs fabricated under the various kinds of anodizing conditions, the PNS anodized at a current density of 10mA/$cm^2$ for 20 sec has the lowest turn-on voltage and the highest emission current than those of others. Also, the electron emission properties were investigated as functions of measuring temperature and the different thickness of Au film as a top-electrode.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.2
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• pp.147-152
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• 2016

In this study, we fabricated Ag-based electrochemical metallization memory devices which is also called conductive-bridge random-access memory (CBRAM) in order to investigate the resistive switching behavior depending on the bottom electrode (BE). RRAM cells of two different layer configurations having $Ag/Si_3N_4/TiN$ and $Ag/Si_3N_4/p^+$ Si are studied for metal-insulator-metal (MIM) and metal-insulator-silicon (MIS) structures, respectively. Switching voltages including forming/set/reset are lower for MIM than for MIS structure. It is found that the workfunction different affects the performances.

• Journal of information and communication convergence engineering
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• v.1 no.1
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• pp.23-26
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• 2003

A photodiode capable of obtaining a sufficient photo/dark current ratio at both a forward bias state and a reverse bias state is proposed. The photodiode includes a glass substrate, an aluminum film formed as a lower electrode over the glass substrate, an alumina film formed as a schottky barrier over the aluminum film, a hydrogenated amorphous silicon film formed as a photo conduction layer over a portion of the alumina film, and a transparent conduction film formed as an upper electrode over the hydro-generated amorphous silicon film. Growth of high quality alumina($Al_{2}O_{3}$) film using anodizing technology is proposed and analyzed by experiment. We have obtained the film with a superior characteristics

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.54-54
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• 2009

Ag thick film has been used for electrode materials with the excellent conductivity. Ag electrode is used in screen-printed silicon solar cells as a electrode material. Compared to photolithography and buried-contact technology, screen-printing technology has the merit of fabricating low-priced cells and enormous cells in a few hours. Ag paste consists of Ag powders, vehicles and additives such as frits, metal powders (Pb, Bi, Zn). Frits accelerate the sintering of Ag powders and induce the connection between Ag electrode and Si wafer. Thermophysical properties of frits and reactions among Ag, frits and Si influence on cell performance. In this study, Ag pastes were fabricated with adding different kinds of frits. After Ag pastes were printed on silicon wafer by screen-printing technology, the cells were fired using a belt furnace. The cell parameters were measured by light I-V to determine the short-circuit current, open-circuit voltage, FF and cell efficiency. In order to study the relationship between the reactivity of Ag, frit, Si and the electrical properties of cells, the reaction of frits and Si wafer on was studied with thermal properties of frits. The interface structure between Ag electrode and Si wafer were also measured for understanding the reactivity of Ag, frit and Si wafer. The excessive reactivity of Ag, frit and Si wafer certainly degraded the electrical properties of cells. These preliminary studies suggest that reactions among Ag, frits and Si wafer should optimally be controlled for cell performances.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1529_1530
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• 2009

The process conditions for fabricating p-type silicon pillars were optimized by controlling current density, bath temperature. To get best process flexibility for pillar arrays formation, three factors affecting pillar formation were changed. First, the solution bath was designed to keep constant temperature during the experiment irrespective of external temperature. Second, the counter Pt electrode was changed from rod type to mesh to obtain uniform distribution of current density. Third, Cr-Cu alloy electrode instead of Cu was used to increase electrode current density.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.1
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• pp.24-28
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• 2005

A micromachined biochip with a three dimensional silicon chamber was developed for the construction of biosensors. Anisotropic etching was used fur the formation of the chamber on the p-type silicon wafer(100) and then was glued to the Pyrex glass bottom-substrate with pre-deposited platinum electrode. The electrochemical characterization of its Pt electrode and Ag/AgCl reference electrode was investigated.