• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1649-1651
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• 2000

Optical properties of $Cd_{1-x}Zn_{x}S$ films deposited by :chemical bath deposition(CBD), which is a very attractive method for low-cost and large-area solar cells, are presented, Especially, in order to control more effectively the zinc component of the films, zinc acetate, which used as the zinc source, mixed in reaction solution after preheating and the pH of the reaction solution decreased with increasing the concentration of zinc acetate. The films prepared after preheating and pH control had larger zinc component and higher optical band gap. As the more zinc substituted for Cd in the films, the optical transmittance improved, while the absorption edge shifts to a shorter wavelength and the optical band gap increased. The photo conductivity of the films was larger than the dark conductivity, while the ratio of those increased with increasing the mole ratio of zinc acetate.

• 한국전기전자재료학회논문지
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• 제30권4호
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• pp.214-217
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• 2017

An IGBT (insulated gate bipolar transistor) device has an excellent current-conducting capability. It has been widely employed as a switching device to use in power supplies, converters, solar inverters, and household appliances or the like, designed to handle high power. The aim with IGBT is to meet the requirements for use in ideal power semiconductor devices with a high breakdown voltage, an on-state voltage drop, a high switching speed, and high reliability for power-device applications. In general, the concentration of the drift region decreases when the breakdown voltage increases, but the on-resistance and other characteristics should be reduced to improve the breakdown voltage and on-state voltage drop characteristics by optimizing the design and structure changes. In this paper, using the T-CAD, we designed the NPT-IGBT (non punch-through IGBT) and FS-IGBT (field stop IGBT) and analyzed the electrical characteristics of those devices. Our analysis of the electrical characteristics showed that the FS-IGBT was superior to the NPT-IGBT in terms of the on-state voltage drop.

• 전기학회논문지
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• 제60권1호
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• pp.100-104
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• 2011

In this work, an optimum condition of electrolytes preparation for photovoltaic cells application was investigated experimentally in terms of impedance and conversion efficiency of the cells. 3-methoxyppropionitrie and redox pairs with LiI and $I_2$ were used as stable solvents for fabrication of electrolyte. Efficiency comparison of the prepared cells carried out for various additives and ionic liquids. From the results, there was an optimum concentration (about 0.3 M) of ionic liquids for efficient cell fabrication. For case of electrolyte using single DMAp additive, the maximum conversion efficiency of the cell was 6.4%($V_{oc}$: 0.78V, $J_{sc}$: 14.4 mA/$cm^2$, ff: 0.57). For case of electrolyte using both DMAp and CEMim additives, the maximum conversion efficiency of the cell was 7.2%($V_{oc}$: 0.79V, $J_{sc}$: 16 mA/$cm^2$, ff: 0.57). From the result of electrochemical impedance measurement, both Z1 and Z3 values of binary additives-based cell decreased compared to those of single additive-based. This is due to the decreased in internal and charge transfer resistivities of the cells.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1992년도 춘계학술대회 논문집
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• pp.105-109
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• 1992

ITO film, 1500${\AA}$ of thickness, onto glass and p-InP wafer was prepared by e-beam evaporator. The bet ITO film had the resistivity 5.3${\times}$10$\^$-3/ $\Omega$-cm, the concentration 6.5${\times}$10$\^$20/cm$\^$-3/, the transmittance above 80%, and the optical energy gap about 3.5eV. The higher pressure of injected oxygen, the less reverse bias saturation current and the more open circuit voltage. Under the optimum evaporation conditions, the efficiency was 7.19% and the series resistance, and the shunt resistance were respectively 8.5%, 3${\alpha}$, and 26K$\Omega$. The interdependence between activation energy and pre-exponential factor was found. We found he surface of the p-InP became n-type and consquently supposed that the buried homojunction formation, that is, n+-ITO/n-InP/p-InP was caused by Sn diffusion or loss of phosphorus in the interface layer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1592-1594
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• 2003

This paper presents the deposition and characterization of microcrystalline silicon(${\mu}c$-Si:H) films by HWCVD(Hot-wire Chemical Vapor Deposition) method at low substrate($300^{\circ}C$). The filament temperature, pressure and $SiH_4$ concentration were determined to be a critical parameter for the deposition of poly-Si films. Series A was deposited under the conditions of $1380^{\circ}C$(Tf), 100 mTorr and $2{\sim}10%\{SC:SiH_4/(SiH_4+H_2)\}$ for 60 min. Series B was deposited under the conditions of $1400{\sim}1450^{\circ}(T_f)$, 30 mTorr and $2{\sim}12%$(SC) for 60 min. The physical characteristics were measured by Raman and FTIR spectroscopy, dark and photoconductivity measurements under AM1.5 illumination.

• Current Photovoltaic Research
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• 제3권1호
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• pp.27-31
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• 2015

It is known that sulfide at the $Cu(In,Ga)Se_2$ ($CIGSe_2$) surface plays a positive role in $CIGSe_2$ solar cells. We investigated the substitution of S with Se on the $CIGSe_2$ surface in S atmosphere. We observed that the sulfur content in the $CIGSe_2$ films changed according to sulfurization temperature and Cu/(In+Ga) ratio. The sulfur content in the $CIGSe_2$ films increased with increasing the annealing temperature and Cu/(In+Ga) ratio. Also Cu migration toward the surface increased at higher temperature. Since high Cu concentration at the $CIGSe_2$ surface is detrimental role, it is necessary to reduce the S annealing temperature as low as $200^{\circ}C$. The cell performance was improved at $200^{\circ}C$ sulfurization.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.792-794
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• 2010

본 연구는 PC1D를 이용하여 태양전지 전류전압 특성곡선및 효율을 분석한 연구이다. 태양전지 전류전압 특성곡선에서 제4상한부분의 면적은 태양전지의 효율을 나타낸다. 곡선인자(Fill Factor)는 개방전압과 단락 전류의 곱에 대한 최대 출력전압과 최대 출력전류의 곱한 값의 비율이다. 본 논문은 태양전지의 최대 효율을 얻기 위해서 도핑 농도를 $1{\times}10^{14}cm^{-3}$부터 $1{\times}10^{17}cm^{-3}$까지 변화시키면서 태양전지의 전류전압 특성곡선 및 최대효율을 분석하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.320-320
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• 2007

Nowadays, ZnO thin films are investigated as transparent conductive electrodes for use in optoelectronics devices including flat displays, thin films transistors, solar cells because of their unique optical and electrical properties. For the use as transparent conductive electrodes, a film has to have low resistivity, high absorption in the ultra violent light region and high optical transmission in the visible region. Different technologies such as electron beam evaporation, chemical vapor deposition, laser evaporation, DC and RF magnetron sputtering and have been reported to produce thin films of ZnO with adequate performance for applications. However, highly transparent and conductive doped-ZnO thin films deposited by a metal-organic decomposition method have not been reported before. In this work, the effect of dopant concentration, heating treatment and annealing in areducing atmosphere on the structure, morphology, electrical and optical properties of ZnO thin films deposited on glass substrates by a Sol-gel method are investigated.

• Membrane and Water Treatment
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• 제13권5호
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• pp.219-225
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• 2022

5th Assessment Report of the Intergovernmental Panel on Climate Change Weather (AR5) predicts that recent severe hydrological events will affect the quality of water and increase water pollution. To analyze changes in water quality due to future climate change, input data (precipitation, average temperature, relative humidity, average wind speed, and solar radiation) were compiled into a representative concentration curve (RC), defined using 8.5. AR5 and future use are calculated based on land use. Semi-distributed emission model Calculate emissions for each target period. Meteorological factors affecting water quality (precipitation, temperature, and flow) were input into a multiple linear regression (MLR) model and an artificial neural network (ANN) to analyze the data. Extensive experimental studies of flow properties have been carried out. In addition, an Acoustic Doppler Velocity (ADV) device was used to monitor the flow of a large open channel connection in a wastewater treatment plant in Ho Chi Minh City. Observations were made along different streams at different locations and at different depths. Analysis of measurement data shows average speed profile, aspect ratio, vertical position Measure, and ratio the vertical to bottom distance for maximum speed and water depth. This result indicates that the transport effect of the compound was considered when preparing the hazard analysis.

• 웰빙융합연구
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• 제6권1호
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• pp.17-22
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• 2023

Purpose: VOCs (volatile organic compounds) are all the organic compounds that react with solar rays and increase the concentration of ozone in the troposphere and are partially also known as carcinogens. The adsorption using activated carbon is usually applied to remove VOCs. Research design, data and methodology: The 20 places of surface coating facilities were selected to evaluate the emission amount of VOCs in Seoul. In addition, the removal efficiency of VOCs in 25 places of automobile coating facilities was evaluated. Results: The average emission amount of VOCs was 10.903 kg/hr from automobile coating facilities, while 3.520 kg/hr from other surface coating facilities. The removal efficiency in adsorption with the combustion catalytic process has the mean value of 87.9% and the regeneration efficiency of activated carbon has the mean value of 95.0%. Conclusions: The removal efficiency in adsorption with the biofiltration process has the mean value of 89.8% and the regeneration efficiency of activated carbon has the mean value of 94.8%. The removal efficiency in the plasma catalyst process has the mean value of 79.3%.