• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.7
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• pp.382-387
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• 2000

The $CdAl_2S_4 and CdAl_2S_4 : Co^{2+}$ single crystals were grown by the chemical transport reaction method using iodine as a transport agent. The $CdAl_2S_4 and CdAl_2S_4 : Co^{2+}$single crystals were crystallized into a defect chalcopyrite structure. The optical energy gap of the $CdAl_2S_4 and CdAl_2S_4 : Co^{2+}$ single crystals was found to be 3.377 eV and 2.924 eV, respectively, at 300 K. Blue emission with peaks in 456nm~466nm at 280K was observed in the $CdAl_2S_4$ single crystal. Optical absorption and emission peaks due to impurities in the $CdAl_2S_4 Co^{2+}$ single crystal were observed and described as originating from the electron transition between energy levels of the $Co^{2+} ion sited at the Td symmetry point.

• Nuclear Engineering and Technology
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• v.24 no.3
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• pp.228-235
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• 1992

Some soluble species may not be solubility-limited or congruent-released with the matrix species. For example, during the operation of the nuclear reactor, the fission products can be accumulated in the fuel-cladding gap, voids, and grain boundaries of the fuel rods. In the waste package for spent-fuel placed in a geologic repository, the high solubility species of these fission products accumulated in the“gap”, e.g. cesium or iodine are expected to dissolve rapidly when ground water penetrates fuel rods. The time and space dependent mass transport for high solubility nuclides in the gap is analyzed, and its numerical illustrations are demonstrated. The approximate solution that is valid for all times is developed, and validated by comparison with an asymptotic solution and the solution obtained by the numerical inversion of Laplace transform covering the entire time span.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.234-237
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• 2001

FeSi$_2$/Si Layer were grown using FeSi$_2$, Si wafer by the chemical transport reaction method. The directoptical energy gap was found to be 0.871ev at 300 K. The Hall effect is a physical effect arising in matter carrying electric current in the presence of a magnetic field. The effect is named after the American physicist E. H. Hall, who discovered it in 1879. In this paper, we study electrical properties of FeSi$_2$/Si layer And then we measured Hall coefficient Hall mobility, carrier density and Hall voltage according to variation magnetic field and temperature, Because of important Part for it application Various phase of silicide is formed at the metal-Si interface when transition metal contacts to Si. Silicides belong to metallic or semiconducting according to their electrical and optical properties. Metallic silicides are used as gate electrodes or interconnections in VLSI devices. Semiconducting silicides can be used as a new material for IR detectors because of their narrow energy band gap.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.230-233
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• 2001

FeSi$_2$ Layer were grown using FeSi$_2$, Si wafer by the chemical transport reaction method. The directoptical energy gap was found to be 0.87leV at 300 K. The Hall effect is a Physical effect arising in matter carrying electric current in the presence of a magnetic field. The effect is named after the American physicist E.H. Hall, who discovered it in 1879. In this paper, we study electrical properties of FeSi$_2$/Si layer. And then we measured Hall coefficient Hall mobility, carrier density and Hall voltage according to variation magnetic field and temperature, Because of important part for it application various phase of silicide is formed at the metal-Si interface when transition metal contacts to Si. Silicides belong to metallic or semiconducting according to their electrical and optical properties. Metallic silicides are used as gate electrodes or interconnections in VLSI devices. Semiconducting silicides can be used as a new material for IR detectors because of their narrow energy band gap.

• Electrical & Electronic Materials
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• v.9 no.2
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• pp.152-158
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• 1996

Optical absorption and photoconductivity spectra of undoped and Co-doped Cd$_{4}$GeSe$_{6}$ single crystals, grown by the chemical transport reaction using iodine as a transporting agent, were investigated. At 20K, the optical energy gaps of the single crystals are 1.934eV for Cd$_{4}$GeSe$_{6}$ and 1.815eV for Cd$_{4}$GeSe$_{6}$ :Co$^{2+}$. The photoconductivity spectra of these single crystals were closely investigated over the temperature range 20-290K. At 20K, the photoconductivity peaks were located at 1.797eV, 1.347eV for Cd$_{4}$GeSe$_{6}$ and 1.815eV, I,.57eV, 1.46eV and 1.38eV for Cd$_{4}$GeSe$_{6}$ :Co$^{2+}$, respectively.ely.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.3
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• pp.137-141
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• 2002

CdS and $CdS:Co^{2+}$ single crystals were grown by CTR method using iodine as transport material. The grown single crystals have defect chalcopyrite structure with direct band gap. The optical energy band gap was decreased according to add of Co-impurity. We can observed the Co-impurity optical absorption peaks assigned to the $Co^{2+}$ ion sited at the $T_d$ symmetry lattice and we consider that they were attributed to the electron transitions between energy levels of ions.

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.177-181
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• 2001

The conversion efficiency of a cesium iodine coated micro-channel plate is studied. We use the EGS4 code to transport photons and generated electrons until their energies become less than 1keV and 10keV respectively. Among the generated electrons, the emission from the secondary electrons located within the escape depth of 56nm from the photo-converter boundary is estimated by integrating the product of the secondary electrons with a probability depending only on their geometric locations. The secondary electron emission from the generated electrons of energy higher than 100eV is estimated by the 'universal yield curve'. The sum of these provides an estimate for the secondary electron yield and we show that results of applying this algorithm agree with known experimental results. Using this algorithm, we computed secondary electron emissions from a micro-channel plate used in a gas electron multiplier detector that is currently being developed at Korea Atomic Energy Research Institute.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.94-97
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• 2002

CdS and $CdS:Co^{2+}$ single crystals were grown by CTR method using iodine as transport material. The grown single crystals have defect chalcopyrite structure with direct band gap. The optical energy band gap was decreased according to add of Co-impurity. We can observed the Co-impurity optical absorption peaks assigned to the $Co^{2+}$ ion sited at the $T_d$ symmetry lattice and we consider that they were attributed to the electron transitions between energy levels of ions.

• Journal of the Korean Vacuum Society
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• v.4 no.3
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• pp.334-341
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• 1995

IB-AI-VIB2 및 IB-AI-VIB2 :Co2+ 결정을 고순도 원소를 출발 물질로 하고 iodine을 수송 매체로 사용하여 chemical transport reaction method로 성장시켰다. 성장된 결정의 결정구조는 chalcopyrite 구조였으며, energy gap은 direct band gap으로 3.514~1.814 eV 정도로 주어졌으며, cobalt를 불순물로 첨가할 때 energy gap은 감소하였다. IB-AI-VIB2 :Co2+ 결정에서 첨가된 cobalt가 모체결정의 Td symmetry site에 Co2+ ion으로 위치하여, Co2+ ion의 energy 준위 사이의 전자전이에 기인하는 불순물 광흡수 peaks가 나타났다. 이 불순물 광흡수 peaks에 결정장 이론을 적용하여 구산 1st-order spin-orbit coupling parameter(λ)는 -183~ -189cm-1정도였고, 2nd-order spin-orbit coupling parameter(P)는 225~239 cm-1정도였으며, crystal field parameter(Dq)는 328~395cm-1, Racah parameter(B)는 531~552cm-1정도였다.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.13-16
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• 2006

Electro-electrodialysis (EED) experiments were carried out for the HI concentration from HIx $(HI-H_2O-I_2)$ solution to improve the Hl decomposition reaction in the thermochemical water-splitting is (iodine-Sulfur) process. EED cell is composed of the collector electrode and electrolyte. Nafion 117 which was cation exchange membrane used as an electrolyte, and the activated carbon cloth used as an electrode. The HI concentration experiment was carried out using the HIx solution and molar ratio of the $I_2$ were varied from 1 to 3 mole. The cell voltages were decreased as temperature increase. And, membrane properties such as transport number of proton and electro-osmosis coefficient were decreased as temperature increase