• 한국자원식물학회지
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• 제3권2호
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• pp.107-114
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• 1990

In view of the results to have measured metallic elements which is included in 45 sorts of herb medicines and surveyed their distribution, 8 kinds ofmetals including Co, Ge, Ga, TL, Cd, As, 8i, Pb, are never or little includedin almost herb medicines . Other twenty-five sorts of elements (Mo, Sc, Be, V,Ni, Sn, Se, Ba, Cr, Sb, Si, Ti, B, Li, Mg, Ca, Cr, Mn, Fe, Cu, Zn, p, Al, Na,K) are more or Less included in all herb Bedicines ana Na, Ca, p and K aremetals that are included in Large quentities in comrarison with others . Patri-uiae Radix Contains 7 kinds of metal lic elements more than other herb medicinesdoes .

• Current Photovoltaic Research
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• 제3권3호
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• pp.75-79
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• 2015

Recently, $Cu_2ZnSn(S_xSe_{1-x})_4$ (CZTSSe) has been received a tremendous attraction as light absorber material in thin film solar cells (TFSCs), because of its earth abundance, inexpensive and non-toxic constituents and versatile material characteristics. Kesterite CZTSSe thin films were synthesized by sulfo-selenization of sputtered Cu/Sn/Zn stacked metallic precursors. The sulfo-selenization of Cu/Sn/Zn stacked metallic precursor thin films has been carried out in a graphite box using rapid thermal annealing (RTA) technique. Annealing process was done under sulfur and selenium vapor pressure using Ar gas at $520^{\circ}C$ for 10 min. The effect of tuning Se/(S+Se) precursor composition ratio on the properties of CZTSSe films has been investigated. The XRD, Raman, FE-SEM and XRF results indicate that the properties of sulfo-selenized CZTSSe thin films strongly depends on the Se/(S+Se) composition ratio. In particular, the CZTSSe TFSCs with Se/(S+Se) = 0.37 exhibits the best power conversion efficiency of 4.83% with $V_{oc}$ of 467 mV, $J_{sc}$ of $18.962mA/cm^2$ and FF of 54%. The systematic changes observed with increasing Se/(S+Se) ratio have been discussed in detail.

• 한국재료학회지
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• 제4권8호
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• pp.921-926
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• 1994

Gate oxide의 특성은 세정공정에서 사용된 last세정용액에 큰 영향을 받는다. Standard RCA, HF-last, SCI-last, and HF-only 공정들은 gate oxidation하기 전 본 실험에서 행해진 세정공정들이다. 세정공정을 마친 Si기판들은 oxidation furnace에서 $900^{\circ}C$로 thermal oxidation공정을 거치게 된다. 100$\AA$의 gate oxide를 성장시킨 후 lifetime detector, VPD, AAS, SIMS, TEM, 그리고 AFM고 같은 분석장비를 이용하여 oxide의 특성을 평가했다. HF-last와 HF-only 공정에 의해 금속 불순물들이 매우 효과적으로 제거됐음을 알 수 있었다. Oxide의 표면 및 계면 형상은AFM과 TEM 측정을 통하여 관찰하였다. 표면거칠기는 SCI 세정용액을 사용한 splits 실험에서 불균일함이 관찰되었고 HF-only세정공정을 거친 시편 및 계면이 가장 smooth했다.

• 환경영향평가
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• 제17권6호
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• pp.321-333
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• 2008

Considering risks and artificial enrichments of metals in the soils of the study area, the study aims to analyze geology, grain size and geochemistry. Geology is mainly composed of gneisses and phyllites of metamorphic rocks, sandstones, siltstones, shales, tuffs of sedimentary ones and granites and andesites of igneous ones in the area. In the area, mean contents of metals are not meaningful in accordance with petrogenesis. The soil textures of the area are of S, lS and sL of sandy soil, L, scL, cL of loam and C, zC and sC of clayey soil. Mean contents of Ni, Cr, Co and Cu are meaningfully high in loam and clayey soil relative to sandy soil, whereas Ni, Zn, Cd contents are higher in clayey soil than in loam. Those differences imply the metallic contents are dependent to grain size. Based on the metal contents in the soils of the study area, Cu and Zn in loams and Pb in sandy soils are corresponded to soil contamination warning standards, and As showing 75mg/kg of maximum content in loams is assigned to soil contamination countermeasure standards, respectively. Artificial enrichment factor minimized wall rock and grain size relations is over 1 in Cr, Ni and Cu, but the factor is below 1 in average of other metals.

• 전자공학회논문지SC
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• 제46권5호
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• pp.38-43
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• 2009

본 논문에서는 자기 벡터 포텐셜 해석을 통해 3-코일 구조를 갖는 금속 검출기 헤드가 수신 코일에 미치는 유도 전압을 구하고, 금속 물체의 특성이 송신 코일의 임피던스에 미치는 영향을 유도하였다. 이러한 해석을 통하여 최적의 검출 성능을 위한 송신 코일과 수신 코일 간의 거리를 구하였고, 최대 유도 전압을 출력하는 금속의 위치를 유도하였다. 또한 기존의 수식과 비교하여 본 논문의 자기 벡터 포텐셜 해석에 대한 타당성을 입증하였다.

• 한국재료학회지
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• 제27권10호
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• pp.518-523
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• 2017

In commercial solar cells, the pattern of the front electrode is critical to effectively assemble the photo generated current. The power loss in solar cells caused by the front electrode was categorized as four types. First, losses due to the metallic resistance of the electrode. Second, losses due to the contact resistance of the electrode and emitter. Third, losses due to the emitter resistance when current flows through the emitter. Fourth, losses due to the shading effect of the front metal electrode, which has a high reflectance. In this paper, optimizing the number of finger on a $4{\times}4$ solar cell is demonstrated with known theory. We compared the short circuit current density and fill factor to evaluate the power loss from the front metal contact calculation result. By experiment, the short circuit current density($J_{sc}$), taken in each pattern as 37.61, 37.53, and $37.38mA/cm^2$ decreased as the number of fingers increased. The fill factor(FF), measured in each pattern as 0.7745, 0.7782 and 0.7843 increased as number of fingers increased. The results suggested that the efficiency(Eff) was measured in each pattern as 17.51, 17.81, and 17.84 %. Throughout this study, the short-circuit current densities($J_{sc}$) and fill factor(FF) varied according to the number of fingers in the front metal pattern. The effects on the efficiency of the two factors were also investigated.

• Current Photovoltaic Research
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• 제4권1호
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• pp.16-20
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• 2016

$Cu_2ZnSnS_4$ (CZTS) thin films were fabricated by successive electrodeposition of layers of precursor elements followed by sulfurization of an electrodeposited Cu-Zn-Sn precursor. In order to improve quality of the CZTS films, we tried to optimize the deposition condition of absorber layers. In particular, I have conducted optimization experiments by changing the Cu-layer deposition time. The CZTS absorber layers were synthesized by different Cu-layer conditions ranging from 10 to 16 minutes. The sulfurization of Cu/Sn/Zn stacked metallic precursor thin films has been conducted in a graphite box using rapid thermal annealing (RTA). The structural, morphological, compositional, and optical properties of CZTS thin films were investigated using X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and X-ray Flourescenece Spectrometry (XRF). Especially, the CZTS TFSCs exhibits the best power conversion efficiency of 4.62% with $V_{oc}$ of 570 mV, $J_{sc}$ of $18.15mA/cm^2$ and FF of 45%. As the time of deposition of the Cu-layer to increasing, the properties were confirmed to be systematically changed. And we have been discussed in detail below.

• Current Photovoltaic Research
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• 제1권2호
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• pp.82-89
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• 2013

$Cu_2ZnSnS_4$ thin film have been fabricated by rapid thermal annealing of dc-sputtered metal precursor with Cu/ZnSn/Cu stack in sulfur ambient. A CZTS film with a good uniformity was formed at $560^{\circ}C$ in 6 min. $Cu_2SnS_3$ and $Cu_3SnS_4$ secondary phases were present at $540^{\circ}C$ and a trace amount of $Cu_2SnS_3$ secondary phase was present at $560^{\circ}C$. Single-phase large-grained CZTS film with rough surface was formed at $560^{\circ}C$. Solar cell with best efficiency of 4.7% ($V_{oc}=632mV$, $j_{sc}=15.8mA/cm^2$, FF = 47.13%) for an area of $0.44cm^2$ was obtained for the CZTS absorber grown at $560^{\circ}C$ for 6 min. The existence of second phase at lower-temperature annealing and rough surface at higher-temperature annealing caused the degradation of cell performance. Also poor back contact by void formation deteriorated cell performance. The fill factor was below 0.5; it should be increased by minimizing voids at the CZTS/Mo interface. Our results suggest that CZTS absorbers can be grown by rapid thermal annealing of metallic precursors in sulfur ambient for short process times ranging in minutes.

• 전자공학회논문지SC
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• 제47권5호
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• pp.1-8
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• 2010

시장과 공장 환경 변화에 따라 생산관리의 용이성, 조작의 편리성, 높은 산업 안정성등의 요구가 본 논문에서는 네트워크기반의 시스템을 도입하여 단점을 보완한 새로운 고속, 초정밀 취출 로봇 제어기를 개발하였다. 개발된 제어기는 크게 티칭 팬던트와 중앙 서버 PC로 구분된다. 중앙 서버 PC는 관리자에게 전체 공정에 관련된 정보를 제공하게 된다. 티칭 팬던트는 중앙 서버 PC와 사출물 취출 로봇에 다리 역할로 사출로봇을 이용하는 사용자에게 제어 기능 및 사용자 인식, 금형파일 관리등 다양한 기능을 제공하게 된다. 사출물 취출을 위한 제어기 개발은 소프트웨어와 하드웨어 부분으로 나누어진다. 소프트웨어 개발은 3단계로 구분된다. 응용 프로그램과 유저 인터페이스 그리고 디바이스 드라이버로 구분되며, 간단한 디바이스 드라이버에는 따로 구분하지 않고 응용 프로그램에 포함되어 사용하도록 하였다. 하드웨어는 터치패널과 무선 네트워크를 도입하여 인터넷 접속 및 효율적인 공정 제어를 구축할 수 있도록 하였다. 기존의 시스템의 취출 싸이클이 5초였으나, 개선된 시스템을 도입하였을 경우 4초이내였으며, 다양한 무선 네트워크 기능으로 인한 공정 관리 및 생산 관리등 공정의 효율성을 높일 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.276-276
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• 2010

Localized surface plasmon resonance (LSPR) has been explored recently as a promising approach to increase energy conversion efficiency in photovoltaic devices, particularly for thin film hydrogenated amorphous silicon (a-Si:H) solar cells. The LSPR is frequently excited via an electromagnetic (EM) radiation in proximate metallic nanostructures and its primary con sequences are selective photon extinction and local EM enhancement which gives rise to improved photogeneration of electron-hole (e-h) pairs, and consequently increases photocurrent. In this work, high-dielectric-constant (k) $ZrO_2$ (refractive index n=2.22, dielectric constant $\varepsilon=4.93$ at the wavelength of 550 nm) is proposed as spacing layer to enhance the LSPR for application to the thin film silicon solar cells. Compared to excitation of the LSPR using $SiO_2$ (n=1.46, $\varepsilon=2.13$ at the wavelength of 546.1 nm) spacing layer with Au nanoparticles of the radius of 45nm, that using $ZrO_2$ dielectric shows the advantages of(i) ~2.5 times greater polarizability, (ii) ~3.5 times larger scattering cross-section and ~1.5 times larger absorption cross-section, (iii) 4.5% higher transmission coefficient of the same thickness and (iv) 7.8% greater transmitted electric filed intensity at the same depth. All those results are calculated by Mie theory and Fresnel equations, and simulated by finite-difference time-domain (FDTD) calculations with proper boundary conditions. Red-shifting of the LSPR wavelength using high-k $ZrO_2$ dielectric is also observed according to location of the peak and this is consistent with the other's report. Finally, our experimental results show that variation of short-circuit current density ($J_{sc}$) of the LSPR enhanced a-Si:H solar cell by using the $ZrO_2$ spacing layer is 45.4% higher than that using the $SiO_2$ spacing layer, supporting our calculation and theory.