• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.2
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• pp.144-150
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• 2003

The chalcogenide glasses of thin films have the superior property of photoinduced anisotrophy(PA). In this study, we observed the linear dichroism using the irradiation with Polarized He-Ne laser light in the Ag/As$_{40}$ Ge$_{10}$Se$_{15}$ S$_{35}$ multi-layer. Multilayer structures were formed by alternating metal(Ag) and chalcogenide(As$_{40}$ Ge$_{10}$Se$_{15}$ S$_{35}$) thin film. The Ag Polarized photodoping result in reducing the time of saturation anisotropy and increasing the sensitivity of linearly anisotropy intensity As the results, the Ag polarized photodoping will be have a capability of new method that suggests more improvement of photoinduced anisotropy property in the thin films of chalcogenide.ogenide.ide.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.267-270
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• 2004

A silver indium sulfide($AgInS_2$) epilayer was grown by the hot wall epitaxy method, which has not been reported in the literature. The grown $AgInS_2$ epilayer has found to be a chalcopyrite structure and evaluated to be high qualify crystal. From the photocurrent measurement in the temperature range from 30 K to 300 K, the two peaks of A and B were only observed, whereas the three peaks of A, B, and C were seen in the PC spectrum of 10 K. These peaks. are ascribed to the band-to-band transition. The valence band splitting of $AgInS_2$ was investigated by means of the photocurrent measurement. The crystal field splitting, $\ddot{A}cr$, and the spin orbit splitting, $\ddot{A}so$, have been obtained to be 0.150 eV and 0.009 eV at 10 K, respectively. And, the energy band gap at room temperature has been determined to be 1.868 eV. Also, the temperature dependence of the energy band gap, $E_g(T)$, was determined.

• Biomolecules & Therapeutics
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• v.20 no.4
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• pp.399-405
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• 2012

Silver nanoparticles (AgNPs) are widely used nanoparticles and they are mainly used in antibacterial and personal care products. In this study, we evaluated the effect of AgNPs on cell death induction in the murine dendritic cell line DC2.4. DC2.4 cells exposed to AgNPs showed a marked decrease in cell viability and an induction of lactate dehydrogenase (LDH) leakage in a time- and dose-dependent manner. In addition, AgNPs promoted reactive oxygen species (ROS)-dependent apoptosis and AgNP-induced ROS triggered a decrease in mitochondrial membrane potential. The activation of the intracellular signal transduction pathway was also observed in cells cultured with AgNPs. Taken together, our data demonstrate that AgNPs are able to induce a cytotoxic effect in DCs through ROS generation. This study provides important information about the safety of AgNPs that may help in guiding the development of nanotechnology applications.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.671-671
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• 2013

실리콘 태양전지와 박막형 태양전지의 뒤를 이어, 제3세대로 분류되는 양자점 감응형 태양전지(QDSC)에 대한 연구가 활발히 진행되고 있다. 이 태양전지의 TCO로는 주로 ZnO, TiO2가 대부분 사용되고 있으며, 양자점 물질로는 CdS, CdSe, CdTe, PbS, PbSe 등의 카드뮴 및 납을 주 성분으로 하는 물질들에 대한 연구만 중점적으로 이루어지고 있는 실정이다. 이런 물질들은 현재까지 알려진 한도 내에서는 QDSC 효율 중 가장 좋은 효율을 나타내고는 있으나 이런 타입의 QDSC가 상용화된다면 환경에 노출되었을 때에 미치는 악영향이 매우 큰 중금속 물질들로 이루어져 있어, 이를 극복할 수 있는 친환경 성분의 물질에 대한 연구 또한 필요한 시점이다. 따라서 본 연구에서는 CdS를 대체할 수 있는 물질로 Ag2S를 선정, 이에 대한 연구를 진행하였다. Ag2S는 밴드갭이 1.1eV의 물질로, CdS의 2.3 eV와 비교해 상당히 작은 밴드갭을 가져 월등히 넓은 영역에서 빛을 흡수할 수 있다는 장점을 가지고 있으며, 동시에 이로 인한 전자-정공 재결합이 빨라 태양전지로 제작시에 Voc가 낮게 형성된다는 단점도 가지고 있다. 태양전지에 사용된 TCO물질은 ZnO 나노선을 사용했으며, 본 연구실에서 기존에 개발한 수열합성법을 통해 제작하였다. 이를 활용하여 최종적으로 제작한 태양전지의 효율은 CdS/ZnO QDSC가 1.2%, Ag2S/ZnO QDSC가 1.2%로 동일한 성능을 나타냈으며, CdS를 대체할 물질로 Ag2S의 가능성을 보여준 결과라 할 수 있다.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.2
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• pp.91-97
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• 2014

With Pb-free solder joints containing Sn-Ag-Cu-based ternary alloys (Sn-1.0 wt.%Ag-0.5Cu and Sn-4.0Ag-0.5Cu) and Sn-Ag-Cu-In-based quaternary alloys (Sn-1.0Ag-0.5Cu-1.0In, Sn-1.2Ag-0.5Cu-0.4In, Sn-1.2Ag-0.5Cu-0.6In, and Sn-1.2Ag-0.7Cu-0.4In), fracture-mode change, shear strengths, and fracture energies were observed and measured under a high-speed shear test of 500 mm/s. The samples in each composition were prepared with as-reflowed ones or solid-aged ones at $125^{\circ}C$ to 500 h. As a result, it was observed that ductile or quasi-ductile fracture modes occurs in the most of Sn-Ag-Cu-In samples. The happening frequency of a quasi-ductile fracture mode showed that the Sn-Ag-Cu-In joints possessed ductile fracture properties more than that of Sn-3.0Ag-0.5Cu in the high-speed shear condition. Moreover, the Sn-Ag-Cu-In joints presented averagely fracture energies similar to those of Sn-Ag-Cu joints. While maximum values in the fracture energies were measured after the solid aging for 100 h, clear decreases in the fracture energies were observed after the solid aging for 500 h. This result indicated that reliability degradation of the Sn-Ag-Cu-In solder joints might accelerate from about that time.

• Journal of the Korean Ceramic Society
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• v.51 no.1
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• pp.1-6
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• 2014

Here we report improved photo-catalytic effect of $Ag_2S$ under visible light using carbon nano-tubes (CNT) modified with $Ag_2S$ nanoparticles. The optical properties, structural properties and compositional analysis, as well as the photo-electrochemical properties of the prepared composites were investigated. It was found that the photocurrent density, and the photo-catalytic effect, was increased by modification of CNT in this way. Compared with the separate effects of $Ag_2S$ and CNT nanoparticles, the photocatalytic effect of CNT-modified-with-$Ag_2S$ composites, increased significantly due to a synergistic effect between the CNT and the $Ag_2S$ nanoparticles.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.2
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• pp.211-220
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• 1998

The stochiometric composition of $AgGaS_2$polycrystal source materials for the single crystal thin films were prepared from horizontal furnace. From the extrapolation method of X-ray diffraction patterns, it was found that the polycrystal $AgGaS_2$has tetragonal structure of which lattice constant $a_0\;and \;c_0$ were 5.756 $\AA$ and 10.305 $\AA$, respectively. $AgGaS_2$single crystal thin film was deposited on throughly etched GaAs(100) substrate from mixed crystal $AgGaS_2$by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were $590^{\circ}C$ and $440^{\circ}C$ respectively, and the growth rate of the single crystal thin films was about 0.5 $mu \textrm{m}$/h. The crystallinity of the grown single crystal thin films was investigated by the DCRC (double crystal X-ray diffraction rocking curve). The optical energy gaps were found to be 2.61 eV for $AgGaS_2$single crystal thin films at room temperature. The temperature dependence of the photocurrent peak energy is well explained by the Varshni equation, then the constants in the Varshni equation are given by${\Alpha};=;8.695{\times}10^{-4};eV/K,and;{\beta};=;332;K$. from the photocurrent spectra by illumination of polarized light of the $AgGaS_2$single crystal thin film, we have found that crystal field splitting $\Delta$Cr was 0.28 eV at 20 K. From the PL spectra at 20 K, the peaks corresponding to free and bound excitons and a broad emission band due to D-A pairs are identified. The binding energy of the free excitons are determined to be 0.2676 eV and 0.2430 eV and the dissociation energy of the bound excitons to be 0.4695 eV.

• Bulletin of the Korean Chemical Society
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• v.21 no.7
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• pp.675-678
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• 2000

The reaction between silver (I) and thiomicher's ketone (TMK) was sensitive at pH 5 and 8 in the presence of non-ionic or anion surfactant. We studied the complex solution and determined the properties by beta-correction spectrophotometry, which included the complex ratio and the stability constant of the complex. The results showed that complex Ag(TMK)2 was formed in the presence of alkylphend ethoxylates (emulsifier OP) and Ag(TMK)2 was formed in the presence of sodium dodecyl benzene sulfonate (SDBS). Their real absorptivities are as follows: $\varepsilonAg(TMK)540$ = 5.23 ${\times}$ 10(4), $\varepsilonAg(TMK)2(555)$ = l.05 ${\times}$ 10(5) Lmol(-l)cm(-1) both at pH 5 and $\varepsilonAg(TMK)2(555)$ = 7,52 ${\times}$ 10(4)lmol(-1)cm(-1) at pH 8. The stability constant of complex Ag(TMK) was equal to 1.23 ${\times}$ 10(5) at pH 5 and that of Ag(TMK)2 8.29 ${\times}$ 10(9) at pH 5 and 1.15 ${\times}$ 10(11) at pH 8.

• Progress in Superconductivity
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• v.1 no.1
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• pp.51-55
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• 1999

A Ni/Ag/Stainless steel 310S(SS310S) multi-layer sheet has been fabricated by a combination of vacuum brazing, cold rolling and texture annealing processes. After heat-treating the thin Ni/Ag/SS310S multi-layer sheet at $900^{\circ}C$ for 2h, development of (100)<001>cube texture on Ni surface was revealed by (111) pole figure. Quantitative chemical analysis was made by EPMA for the cross-section of the Ni/Ag/SS310S multi-layer sheet. EPMA results showed that Ag diffusion into the Ni layer, which may suppress the cube texture development, was negligible. A small amount of Cr atoms were detected in the Ni layer. It showed that Ag can be used as a chemical barrier of alloying element atoms in Ni layer for the Ni/Ag/SS310S multi-layer sheet and a strong cube texture was developed for the Ni layer in the Ni/Ag/SS310S multi-layer sheet.

• Corrosion Science and Technology
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• v.6 no.2
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• pp.50-55
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• 2007

The smaller size and higher integration of advanced electronic package systems result in severe electrochemical reliability issues in microelectronic packaging due to higher electric field under high temperature and humidity conditions. Under these harsh conditions, electronic components respond to applied voltages by electrochemical ionization of metal and the formation of a filament, which leads to short-circuit failure of an electronic component, which is termed electrochemical migration. This work aims to evaluate electrochemical migration susceptibility of the pure Sn, Sn-3.5Ag, Sn-3.0Ag-0.5Cu solder alloys in $Na_{2}SO_{4}$. The water drop test was performed to understand the failure mechanism in a pad patterned solder alloy. The polarization test and anodic dissolution test were performed, and ionic species and concentration were analyzed. Ag and Cu additions increased the time to failure of Pb-free solder in 0.001 wt% $Na_{2}SO_{4}$ solution at room temperature and the dendrite was mainly composed of Sn regardless of the solders. In the case of SnAg solders, when Ag and Cu added to the solders, Ag and Cu improved the passivation behavior and pitting corrosion resistance and formed inert intermetallic compounds and thus the dissolution of Ag and Cu was suppressed; only Sn was dissolved. If ionic species is mainly Sn ion, dissolution content than cathodic deposition efficiency will affect the composition of the dendrite. Therefore, Ag and Cu additions improve the electrochemical migration resistance of SnAg and SnAgCu solders.