• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.134-137
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• 2004

새로운 리튬 2차전지용 양극활물질인 Li[NiMnCo]O2를 간단히 합성할 수 있는 방법과 Si의 doping에 의해 그 특성을 향상하였다. 원하는 당량비의 Li, Ni, Co, Mn의 nitrate를 고순도의 에탄올에 용해하고 여기에 Si의 원료물질로서 poly(methyl phenyl siloxane)을 원하는 양(전체 전이금속 이온의 $2{\sim}10\;mol%$)만큼 첨가한 후 약 30분 정도 교반하였다. 이 용액을 약 $70{\sim}80^{\circ}C$ 정도의 온도에서 고점도의 진흙 상태가 될 정도로 가열하고 $450{\sim}500^{\circ}C$의 온도에서 약 5시간 정도 열처리 하여 유기물이 없는 상태의 전구체를 제조하였다. 이 전구체를 분말형태로 분쇄하고 $600{\sim}650^{\circ}C$ 정도의 온도에서 3시간, $900{\sim}950^{\circ}C$ 정도의 온도에서 5시간 연속적으로 열처리 하여 최종 활물질을 제조하였다. 이렇게 제조된 활물질은 175mAh/g 정도의 높은 비용량을 나타내었으며 4.5V 충전 조건에도 우수한 수명특성을 나타내었다. Si이 doping되지 않은 활물질에 비해 Si이 doping된 물질은 율특성, 수명특성에서 보다 우수한 특성을 나타내었는데 이것은 층상구조 활물질의 격자상수 증가와 impedance 증가 억제에 기인한 것으로 분석되었다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.10
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• pp.799-802
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• 2011

In this study, SiC single-crystal ingots were prepared on two seed crystals with different doping level by using the physical vapor transport (PVT) technique; then, SiC crystal wafers sliced from the grown SiC ingot were systematically investigated to find the effect of seed doping level on the doping concentration and crystal quality of the SiC. To exclude extra effects induced by adjustment of the process parameters, we simultaneously grew the SiC crystals on two seed crystals with different level, which were fabricated from previous two SiC crystal ingots.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.450-451
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• 2008

Amorphous silicon Solar cell has n-i-p structure in general, and each layer's thickness and doping concentration are very important factors which are as influential on efficiency of salar cell. Using AFORS HET simulation to get the high efficiency, by adjusting n layer's thickness and doping concentration, p layer's doping concentration. The optimized values are a-Si:H(n)'s thickness of 1nm, a-Si:H(n)r's doping concentration of $2\times10^{20}cm^{-3}$, a-Si:H(p+)r's doping concentration of $1\times10^{19}cm^{-3}$. After optimization, the solar cell shows $V_{oc}$=679.5mV, $J_{sc}$=39.02mA/$cm^2$, FF=83.71%, and a high Efficiency=22.21%. Though this study, we can use this study for planning or manufacturing solar cell which has high efficiency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.195-196
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• 2008

Doping depth, doping concentration, and resistivity of crystalline silicon solar cell are variables which take important portion in cell's efficiency. To get highly efficient solar cell, PC1D is used to calculate $I_{sc}$, $V_{oc}$, and $P_{max}$. Depth factor, peak doping, and base resistivity was used as variables. As a result, the optimized value of emitter peak doping is $1\times10^{19}cm^{-3}$, depth factor is $1{\mu}m$, and base $\rho$ is $ 0.1\Omega$-cm. Under the optimized condition, the solar cell gets efficiency 19.03(%).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.4
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• pp.203-207
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• 2018

In this work, we investigate the effects of lithium doping on the electric performance of solution-processed n-type zinc tin oxide (ZTO)/p-type silicon carbide (SiC) heterojunction diode structures. The proper amount of lithium doping not only affects the carrier concentration and interface quality but also influences the temperature sensitivity of the series resistance and activation energy. We confirmed that the device characteristics vary with lithium doping at concentrations of 0, 10, and 20 wt%. In particular, the highest rectification ratio of $1.89{\times}107$ and the lowest trap density of $4.829{\times}1,022cm^{-2}$ were observed at 20 wt% of lithium doping. Devices at this doping level showed the best characteristics. As the temperature was increased, the series resistance value decreased. Additionally, the activation energy was observed to change with respect to the component acting on the trap. We have demonstrated that lithium doping is an effective way to obtain a higher performance ZTO-based diode.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.6
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• pp.445-449
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• 2020

Non-volatile memory is approaching its fundamental limits with the Si₃N₄ storage layer, necessitating the use of alternative materials to achieve a higher programming/erasing speed, larger storage window, and better data retention at lower operating voltage. This limitation has restricted the development of the charge-trap memory, but can be addressed by using high-k dielectrics. The paper reviews the doping of nitrogen, titanium, and yttrium on high-k dielectrics as a storage layer by comparing MONOS devices with different storage layers. The results show that nitrogen doping increases the storage window of the Gd₂O₃ storage layer and improves its charge retention. Titanium doping can increase the charge capture rate of HfO₂ storage layer. Yttrium doping increases the storage window of the BaTiO₃ storage layer and improves its fatigue characteristics. Parameters such as the dielectric constant, leakage current, and speed of the memory device can be controlled by maintaining a suitable amount of external impurities in the device.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.139-143
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• 1997

The doping effects of Mg and/or Fe ions on congruent LiNbO$_3$ single crystal growth were studied in order to clarify the roles of MgO in Fe doped LiNbO$_3$ single crystals. The effective distribution coefficienct of Fe was found decreased drastically from 0.85 to 0.5 by the addition of MgO into the LiNbO$_3$ melt. M ssbauer spectra revealed that the addition of MgO reduces the occurrence of Fe2+ ions during growth in air. Therefore, it is likely that there would be two important roles of MgO in Fe doped LiNbO$_3$. One is to suppress the incorporation of all Fe ions, and the other is to reduce the concentration of Fe2+ ions among the total Fe ions.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.4
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• pp.210-218
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• 2000

For the fabrication of $YBa_2Cu_3O_x$ thick film, a substrate of $Y_2BaCuO_5$ was fabricated by adding $CeO_2$ into $Y_2BaCuO_5$ and two types of doping materials added with binder material were prepared. Each doping material was patterned on $Y_2BaCuO_5$substrate by the screen printing method and then was annealed at the temperature with a few step. It could be observed by X-ray diffraction patterns and SEM photographs that through the diffusion process of the $Y_2BaCuO_5$ and each doping material, the $YBa_2Cu_3O_x$ phase was formed. And with n additive of $CeO_2$ the thickness of formed $YBa_2Cu_3O_x$decreased. From the experiment of current limiting on thick film, the sample with thiner thickness of $YBa_2Cu_3O_x$ showed the more effective characteristics of current limiting.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1319-1322
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• 2008

$CsN_3$ was developed as a novel n doping material with air stability and low deposition temperature. Evaporation temperature of $CsN_3$ was similar to that of common hole injection material and it worked well as a n dopant in electron transport layer. Driving voltage was lowered and high power efficiency was obtained in green phosphorescent devices by using $CsN_3$ as a dopant in electron transport layer. It could also be used as a charge generation layer in combination with $MoO_3$. In addition, n doping mechanism study revealed that $CsN_3$ is decomposed into Cs and $N_2$ during evaporation. This is the first work reporting air stable and low temperature evaporable n dopant in organic light-emitting diodes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.553-556
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• 1999

This paper presents a proper condition to achieve above 19 % conversion efficiency using PC1D simulator. Cast poly-Si wafers with resistivity of 1 $\Omega$-cm and thickness of 250 ${\mu}{\textrm}{m}$ were used as a starting material. Various efficiency influencing parameters such as rear surface recombination velocity and minority carrier diffusion length in the base region, front surface recombination velocity, junction depth and doping concentration in the Emitter layer, BSF thickness and doping concentration were investigated. Optimized cell parameters were given as rear surface recombination of 1000 cm/s, minority carrier diffusion length in the base region 200 ${\mu}{\textrm}{m}$, front surface recombination velocity 100 cnt/s, sheet resistivity of emitter layer 100 $\Omega$/$\square$, BSF thickness 5 ${\mu}{\textrm}{m}$, doping concentration 5$\times$10$^{19}$ cm$^3$ . Among the investigated variables, we learn that a diffusion length of base layer acts as a key factor to achieve conversion efficiency higher than 19 %. Further details of simulation parameters and their effects to cell characteristics are discussed in this paper.