• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.515-517
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• 2003

In order to assess the risk of adverse health effects on human exposure to arsenic and heavy metals influenced by past mining activities, environmental geochemical surveys were undertaken in the abandoned metal mine areas (Dongil Au-Ag-Cu-Zn, Okdong Cu-Pb-Zn, Songcheon Au-Ag, Dongjung Au-Ag-Pb-Zn, Dokok Au-Ag-Cu and Hwacheon Au-Ag-Pb-Zn mines). Arsenic and other heavy metals were highly elevated in the tailings from the Dongil, the Songcheon and the Dongjung mines. High concentrations of heavy metals except As were also found in tailings from the Okdong, the Dokok and the Hwacheon mines. These significant concentrations can impact on soils and waters around the tailing dumps. Risk compounds deriving from mine sites either constitute a toxic risk or a carcinogenic risk. The hazard index (H.I.) of As in the Dongil, the Okdong, the Songcheon and the Hwacheon mine areas was higher value more than 1.0. In the Okdong and the Songcheon mine areas, H.I. value of Cd exceeded 1.0. These values of As and Cd were the highest in the Songcheon mine area. Therefore, toxic risks for As and Cd exist via exposure (ingestion) of contaminated soil, groundwater and rice grain in these mine areas. The cancer risk for As in stream or ground water used for drinking water from the Songcheon, the Dongil, the Okdong, the Dongjung and the Hwacheon mine areas was 3E-3, 8E-4, 7E-4, 2E-4 and 1E-4, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 제4회 영호남학술대회 논문집
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• pp.84-91
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• 2002

The stochiometric composition of $AgGaS_2$/GaAs polycrystal source materials for the $AgGaS_2$/GaAs epilayer was prepared from horizontal furnace. From the extrapolation method of X-ray diffraction patterns it was found that the polycrystal $AgGaS_2$/GaAs has tetragonal structure of which lattice constant an and Co were 5.756 $\AA$ and 10.305 $\AA$, respectively. $AgGaS_2$/GaAs epilayer was deposited on throughly etched GaAs(100) substrate from mixed crystal $AgGaS_2$/GaAs by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were $590^{\circ}C$ and $440^{\circ}C$ respectively. The crystallinity of the grown $AgGaS_2$/GaAs epilayer was investigated by the DCRC (double crystal X-ray diffraction rocking curve). The optical energy gaps were found to be 2.61 eV for $AgGaS_2$/GaAs epilayer 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 $\beta=332K$. From the photocurrent spectra by illumination of polarized light of the $AgGaS_2$/GaAs epilayer, 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.

• 한국결정성장학회지
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• 제4권1호
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• pp.63-70
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• 1994

초이온도전체 ${\beta}-Ag_3SI$ 단결정을 AgI와 $AG_2S$의 혼합물을 반응시켜서 열처리하여 얻었다. 성장시킨 단결정은 직경 $200{mu}m$ 정도의 구상으로 성형시켰다. 실온에서 X-선 단결정 해석법을 이용하여 정밀한 결정구조 해석을 행했다. 이들 결정구조의 해석결과 ${\beta}-Ag_3SI$의 $Ag^+$는 6-배위의 3c자리보다 4-배위의 12h자리에 점유함이 밝혀졌다. $Ag^+$의 확률밀도분포(probabilty density function)로 부터 [110]방향에서 $Ag^+$의 one-particle potential(o.p.p.)을 계산하였다.${beta}-Ag_3SI$ 구조의(001)면에서 $Ag^+$가 확산에 필요한 활성화에너지는 0.012eV라는 것이 o.p.p.곡선에 의해 계산되었다.

• 대한전자공학회논문지
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• 제23권5호
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• pp.706-711
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• 1986

The AgGa1-xInxSe2 films are deposited by a flash evaporation method onto pyrex glass substrates at temperatures between 5\ulcorner and 360\ulcorner. The single crystalline films which have X-ray diffraction peak of only (112) plane are preared at substrate temperature above 360\ulcorner. The prepared AgGa 1-xInxSe2 films are high photosensitive. The temperature coefficients of energy gap are found to be (-1.2~-4.0)x10**4 eV/K and (-3.1~-5.2)x10**-4 eV/K, and that of peak energy of spectral photoresponse curve are found to be (-1.1 ~ -3.0)x10**-4 eV/K(50K~100K) and (-2.4~-5.1)x10**-4 eV/K(100K~300K).

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 전문대학교육위원 P
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• pp.10-12
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• 1999

Optical properties of $Zn_2AgGaSe_4$ and $Zn_2AgGaSe_4$:$Co^{2+}$ crystals are investigated in the visible and near-infrared regions at 298K. The direct band gap at 298K is 1.630eV for the $Zn_2AgGaSe_4$ and 1.567eV for the $Zn_2AgGaSe_4$:$Co^{2+}$ crystals, respectively. In the optical absorption and PAS spectrum of the $Zn_2AgGaSe_4$:$Co^{2+}$, we observed five impurity absorption peaks at $4220cm^{-1}$, $5952cm^{-1}$, $12422cm^{-1}$, $12987cm^{-1}$ and $14184cm^{-1}$. These impurity absorption peaks are attributed to the electronic transitions between the split energy levels of $Co^{2+}$ ions with Td symmetry of $Zn_2AgGaSe_4$ host lattice. The crystal field parameter Dq, the Racah parameter B and the spin-orbit coupling parameter $\lambda$ are given by $442cm^{-1}$, $425cm^{-1}$ and $440cm^{-1}$, respectively.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.461.1-461.1
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• 2014

본 연구진에서는 기존에 Ag2S 양자점을 흡광층으로 활용하여 양자점 감응형 태양전지(QDSC)를 제작, 그 성능과 특징을 분석하여 발표한 바 있다. 기존 연구에서 제작된 Ag2S QDSC는 11 mA/cm2의 비교적 높은 광전류와 260 mV의 비교적 낮은 전압으로 인해 1.2%의 광전환효율 성능을 나타내는 것으로 보고되었다. 추후 연구로 진행된 본 결과에서는, 기존에 Single absorber로 사용된 Ag2S의 한계를 보완하기 위해 CdS를 도입하여 co-sensitization을 활용하였다. CdS는 약 2.3 eV의 밴드갭 에너지를 갖는 물질로, 1.1 eV의 밴드갭을 갖는 Ag2S에 비해 흡광 영역은 좁지만 그만큼 전자-정공 재결합을 억제할 수 있는 장점을 가지고 있다. 또한, 전도층으로 사용한 n-type 물질인 ZnO 나노선과의 밴드구조가 매우 적합하게 조화되어, ZnO/CdS/Ag2S 순서로 이종구조를 접합시켰을 때 세 물질의 Conduction band level과 Valence band level이 순차적으로 연결되는 cascade-shaped 밴드구조를 이루게 된다. 빛을 받아 Ag2S와 CdS에서 생성된 전자는 이 cascade 모양의 conduction band를 따라 순차적으로 ZnO로 잘 전달되게 되어, 효율 향상에 큰 도움을 주었다. 이런 장점들로 인해, CdS-Ag2S co-sensitized QDSC는 Ag2S QDSC에 비해 2배나 향상된 효율인 2.4%를 기록하였으며, 이는 IPCE spectrum 측정 등으로 근거가 뒷받침되었다.

• 대한화학회지
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• 제34권6호
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• pp.527-533
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• 1990

AgI(80 mol%)를 기질로 하여 AgBr 15 mol% + CuI 5mol%, AgBr 10 mol% + CuI 10mol%, AgBr 5 mol% + CuI 5mol%의 계를 제조하여 이들의 이온 전도성을 상온에서 200$^{\circ}C$까지 임피던스분석기(impedance analyzer)를 이용하여 측정한다. 이 온도영역에서 활성화에너지는 0.6∼0.7 eV를 얻을 수 있었으며, 5 mol% AgBr계의 이온 전도성이 가장 컸으며 활성화에너지는 가장 작음을 보였다.

• 한국전기전자재료학회논문지
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• 제26권7호
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• pp.510-514
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• 2013

In order to prevent heat loss that occurs through the glass, low-emissivity (Low-E) coating methods with good insulating properties and high transmittance were used. InGaZnO/Ag/InGaZnO (IGZO/Ag/IGZO) multilayer thin films have been deposited on XG glass substrate by RF magnetron sputtering. Depending on the different thickness of Ag in multilayer films, the structural and optical properties of Low-E multilayer films were analyzed. By XRD analysis results, the multilayer thin films were observed to be amorphous structure regardless of Ag thickness. According to the AFM results, surface morphology of the multilayer films was observed and compared. Using UV-VIS spectroscopy, low emissivity property has been observed clearly with the transmittance of higher than 85% at visible range and lower than 30% at IR range.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.122-123
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• 2007

Single crystal $AgGaSe_2$ layers were grown on thoroughly etched semi-insulating GaAs(100) substrate at $420^{\circ}C$ with hot wall epitaxy (HWE) system by evaporating $AgGaSe_2$ source at $630^{\circ}C$. The temperature dependence of the energy band gap of the $AgGaSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g$(T)=1.9501 eV - $(8.79{\times}10^{-4}\;eV/K)T^2$/(T+250 K). The crystal field and the spin-orbit splitting energies for the valence band of the $AgGaSe_2$ have been estimated to be 0.3132 eV and 0.3725 eV at 10 K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}_5$ states of the valence band of the $AgGaSe_2$. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1^-},\;B_{1^-},\;and\;C_{1^-}$exciton peaks for n=1.

• 전기화학회지
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• 제11권3호
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• pp.170-175
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• 2008

다중 생체시료 검출을 위한 바이오센서 연구를 위하여 각기 두 전위를 갖는 오스뮴 고분자를 함께 탄소 전극 (Screen Printed Carbon Electrodes) 위에 고정하였다. 새로운 개념의 다중 생체시료 검출 바이오센서 연구위하여 과산화수소의 환원과 글루코스의 산화에 관여하는 환원 효소와 산화 효소를 각각 이용하였다. 실험 목적에 위하여 염소 작용기 ($E^{O'}$ + 0.520 vs. Ag/AgCl)와 메톡시 작용기 ($E^{O'}$ + 0.150 vs. Ag/AgCl)를 각각 포함하는 두 개의 오스뮴 고분자를 합성하였다. 전자는 과산화수소의 환원에 대하여 좋은 촉매전류신호를 보였고, 후자는 당의 산화에 대하여 효과적인 촉매전류신호를 보였다.