• Solar Energy
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• v.11 no.3
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• pp.74-83
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• 1991

In this study, the (p)ZnTe/(n)Si solar cell and (n)CdS-(p)ZnTe/(n)Si poly-junction thin film are fabricated by vaccum deposition method at the substrate temperature of $200{\pm}1^{\circ}C$ and then their electrical properties are investigated and compared each other. The test results from the (p)ZnTe/(n)Si solar cell the (n)CdS-(p)ZnTe/(n)Si poly-junction thin fiim under the irradiation of solar energy $100[mW/cm^2]$ are as follows; Short circuit current$[mA/cm^2]$ (p)ZnTe/(n)Si:28 (n)CdS-(p)ZnTe/(n)Si:6.5 Open circuit voltage[mV] (p)ZnTe/(n)Si:450 (n)CdS-(p)ZnTe/(n)Si:250 Fill factor (p)ZnTe/(n)Si:0.65 (n)CdS-(p)ZnTe/(n)Si:0.27 Efficiency[%] (p)ZnTe/(n)Si:8.19 (n)CdS-(p)ZnTe/(n)Si:2.3 The thin film characteristics can be improved by annealing. But the (p)ZnTe/(n)Si solar cell are deteriorated at temperatures above $470^{\circ}C$ for annealing time longer than 15[min] and the (n)CdS-(p)ZnTe/(n)Si thin film are deteriorated at temperature about $580^{\circ}C$ for longer than 15[min]. It is found that the sheet resistance decreases with the increase of annealing temperature.

• Korean Journal of Materials Research
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• v.9 no.12
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• pp.1155-1159
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• 1999

Thin film solar cells on a glass/$SnO_2$ substrate with p-SiC/i-Si/n-Si heterojunction structures were fabricated using a plasma-enhanced chemical-vapor deposition system. The photovoltaic properties of the solar cells were examined with varying the gas phase composition, x=$CH_4/\;(SiH_4+CH_4)$, during the deposition of the p-SiC layer. In the range of x=0~0.4, the efficiency of solar cell increased because of the increased band gap of the p-SiC window layer. Further increase in the gas phase composition, however, led to a decrease in the cell efficiency probably due to in the increased composition mismatch at the p-SiC/i-Si layers. As a result, the efficiency of a glass/$SnO_2$/p-SiC/i-SiC/i-Si/n-Si/Ag thin film solar cell with $1cm^2$ area was 8.6% ($V_{oc}$=0.85V, $J_{sc}$=16.42mA/$cm^2$, FF=0.615) under 100mW/$cm^2$ light intensity.

• Journal of Korea Foundry Society
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• v.17 no.2
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• pp.180-187
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• 1997

The influence of solidification condition on the segregation of SiC particles in the $Al-xSi/6wt%SiC_p$(x: 6, 10, 14, 18${\cdot}$wt%) composites was investigated in the study. The results are as follows: 1) During the counter-gravity unidirectional solidification of $Al-Si/SiC_p$ composites melt, most of the SiC particles are pushed to the top of the casting. 2) The SiC particles pushing in the $Al-Si/SiC_p$ composite melts are not observed, when the interface velocity of melts increases more than 1.41 ${\mu}m/sec$. 3) The SiC particles are entrapped in the interdendrite regions, when the sizes of SiC particles in the $Al-Si/SiC_p$ composites are large than ${\varphi}22{\mu}m$.

• Korean Journal of Environmental Agriculture
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• v.26 no.4
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• pp.286-296
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• 2007

To increase phosphate (P) availability in soils, the efficiency of silicate (Si) in reducing P adsorption was investigated by competitive adsorption tests under changing conditions of pH, ion concentrations, and order of anion addition along with single adsorption properties of each ion at $20^{\circ}C$. In the single ion adsorption study, P and Si ions showed the opposite reaction patterns: phosphate adsorption decreased with increasing pH and attained adsorption maximum however, silicate adsorption increased with increasing pH without attaining adsorption maximum. Phosphorus and Si adsorption were influenced by pH in the range of 5.0 - 9.0 and the type and amount of P and Si concentration. Silicate added to soil before P or in a mixture with P significantly reduced P adsorption above pH 7.0; however, there was no significant Si-induced decreased in P adsorption at pH 5.0 when anions were added as mixture. The efficiency of Si in reducing P adsorption increased with increasing Si concentration and pH. The effect of P on Si adsorption was relatively small at pH 5.0 and no effect of P on silicate adsorption was observed at pH 9.0. The presence of Si strongly depressed P adsorption when Si was added before P compared to P and Si added as a mixture. These results suggest that application of Si may decrease P adsorption and increase the availability of P in soils. Furthermore, a Si source would be better to add before P application to enhance the availability of P in soils.

• Composites Research
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• v.25 no.4
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• pp.93-97
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• 2012

Carbon nano fibers (CNFs) reinforced magnesium alloy (AZ91) matrix composites have been fabricated by liquid pressing process. In order to improve the dispersibility of CNFs and the wettability with magnesium alloy melt, CNFs were mixed with submicron sized SiC particles ($SiC_p$). Also, the mixture of CNFs and $SiC_p$ were coated with Ni by electroless plating. In liquid pressing process, AZ91 melts have been pressed hydrostatically and infiltrated into three reinforcement preforms of only CNFs, the mixture of CNFs and $SiC_p$ (CNF+$SiC_p$), and Ni coated CNFs and $SiC_p$ ((CNF+$SiC_p$)/Ni). Some CNFs agglomerates were observed in only CNFs reinforced composite. In cases of the composites reinforce with CNF+$SiC_p$ and (CNF+$SiC_p$)/Ni, CNFs were dispersed homogeneously in the matrix, which resulted in the improvement of mechanical properties. The compressive strengths of CNF+$SiC_p$ and (CNF+$SiC_p$)/Ni reinforced composites were 38% and 28% higher than that of only CNFs composite.

• Journal of Korea Foundry Society
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• v.24 no.2
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• pp.85-93
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• 2004

Mechanical property of hypereutectic Al-Si alloy is changed according to size and distribution of primary Si. Consequently, the study on the refinement for primary Si is progressed for a long time. But such effect of refinement comes out fading phenomena with the lapse of time. Therefore, this study investigated the optimum condition of primary Si refinement for hypereutectic Al-Si alloy. And we observed various primary Si size with P's fading phenomena. The experiment results were as follows. For experiment of primary Si refinement, we made hypereutectic Al-Si alloy with various amounts of P addition. As a result of experiment, we obtained the fine microstructure at 0.01wt.%P. And the optimum condition of P addition, for preventing from growth of primary Si by P fading, is estimated 0.1wt.%P.

• Transactions of Materials Processing
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• v.3 no.4
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• pp.427-439
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• 1994

The high temperature deformation behavior of $SiC_p/Al-Si$ composites and Al-Si matrix was studied by hot torsion test in a range of temperature from $270^{\circ}C$ to $520^{\circ}C$ and at strain rate range of $1.2{\times}10_{-3}~2.16{\times}10_{-1}/sec$. The hot restoration mechanisms for both matrix and composites were found to be dynamic recrystallization(DRX) from the investigation of flow curves and microstructural evolutions. The Si precipitates and SiC particles promoted DRX, and the peak strain$({\varepsilon}_p)$ of the composites was smaller than that of the matrix. Flow stresses of $SiC_p/Al-Si$ composites were found to be generally higher than the matrix, but the difference was quite small at higher temperature due to the decrease of capability of load transfer by SiC particles. With increasing temperature, failure strain of matrix and composites are inclined to increase, the increasing value of failure strain for the $SiC_p/Al-Si$ composites was small compared to that of matrix. The stress dependence of both materials on strain rate() and temperature(T) was examined by hyperbolic sine law, $\.{\varepsilon}=A_1[sinh({\alpha}{\cdot}{\sigma})]_n$exp(-Q/RT)

• Journal of the Korean Chemical Society
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• v.38 no.1
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• pp.1-7
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• 1994

Semiempirical MNDO calculations are employed to study ionicity of OH groups and stability in $T_1-OH-T_2bridges(T_1$ = Al, B and $T_2$ = P, Si) such as found in aluminophosphate family($AlPO_4-5$, BAPO-5, and SAPO-5) molecular sieves. Dimeric model clusters of Al-OH-P, B-OH-P and Al-OH-Si bridges were considered. It is shown that the elongation of the T-O bond, upon replacement of Al by B, occurs preferentially by a local deformation of the Al-O-P bridge. But the elongation of the T-O bond occurs preferentially by a rotation of Al-O-Si bridge upon substitution P for Si. Also, the ionicity of OH groups and stability increase in order to B-OH-P < Al-OH-P < Al-OH-Si bridge.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.209.1-209.1
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• 2013

GaP는 가시광선 발광다이오드을 얻을 수 있는 적절한 재료중의 하나로 해당영역의 파장에 대하여 높은 양자효율을 얻을 수 있고, 깊은 준위 재결합이 없기 때문에 GaP 녹색 및 As 첨가한 GaAsP 적색 LED 에 적용할 수 있습니다. 또한, 상온에서 2.2 eV 에 해당하는 넓은 에너지 밴드갭을 가지고 있으므로, 소음이 없는 자외선 검출기에도 적합합니다. 이 물질에 대한 소자들은 기존에 GaP 기판을 사용하였습니다. 최근, GaP 와 격자상수가 비슷한 Si 기판을 활용하여 그 위에 성장하는 방법에 대한 관심이 많아졌습니다. Si는 물리적 및 화학적으로 안정하고 딱딱한 소재이며 대면적 기판을 쉽게 얻을 수 있어 전자 기기 및 대규모 집적 회로의 좋은 소재입니다. Si 와 대조적으로 GaP은 깨지기 쉬운 재료이며 GaP 기판은 Si와 같은 대면적 기판을 얻을 수 없습니다. 이러한 문제의 한 가지 해결책은 Si 기판위에 GaP 층의 성장입니다. GaP 과 Si의 조합은 현재의 광전소자 들에 더하여 더 많은 응용프로그램들을 가능하게 할 것입니다. 그러나, Si 기판위에 GaP 성장 시 삼차원적 성장 및 역위상 경계면과 같은 문제점들이 발생하므로 질이 높고 균일한 결정의 GaP 를 얻기가 어렵습니다. 따라서, Si 에 GaP 의 성장시 초기 단계를 제어하는 성장 기술이 필요합니다. 본 연구에서는, 유기금속화학증착법을 이용하여 Si 기판위에 양질의 GaP를 얻을 수 있는 최적의 성장조건을 얻고자 합니다. 실험 조건은 Si에 GaP의 에피택셜 성장의 초기 단계에 영향을 주는 V/III 비율, 성장압력, 기판방향 등을 가변하는 조건으로 진행하였습니다. V/III 비율은 100~6400, 성장 압력은 76~380 Torr로 진행하였고, Si 기판은 just(001)과 2~6도 기울어진 (001) 기판을 사용하였습니다.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.7
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• pp.293-297
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• 2003

Silicon dioxide (SiO$_2$) layers were fabricated on Si$_3$N$_4$/SiO$_2$/Si layer structures by low pressure chemical vapor deposition (LPCVD). Potassium and aluminum were then coimplanted by implanting potassium ions with the energy of 100 ［keY］ and dose of 5x10$^{16}$ [cm￣$^2$］ and 1x10$^{17}$ [cm￣$^2$］ into an aluminum buffer layer on the SiO$_2$Si$_3$N4/SiO$_2$/Si structure. The pH, pNa, and pK ion sensitivities of the resulting layers were investigated and compared to those of as-deposited silicon dioxide layer. The pK-sensitivity of the silicon dioxide was enhanced by the K and Al coimplantation. On the contrary, the pH and pNa-sensitivities of the coimplanted silicon dioxides were quite lower than that of the as-deposited silicon dioxide.