• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.65-68
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• 2009

본 연구에서는 eagle 2000 glass위에 APCVD(atmospheric CVD)증착법으로 $SnO_2$:F 박막을 제조하였다. 공정 온도, doping 농도, TTC(Tin tetrachloride)와 $H_2O$, $CH_3OH$의 조성비를 공정 변수로 두었으며, 각 변수에 대한 전기적, 광학적 특성 및 결정성을 확인하였다. hall measurement를 이용 제작된 박막의 전기적 특성을 확인 하였고, uv-VIS spectroscopy, hazemeer를 이용 박막의 광학적 특성을 확인 하였다. 또한 XRD, FESEM, AFM을 이용 박막의 결정성 및 표면 특성을 확인 하였다. 박막의 결정성을 결정짓는 증착 온도의 경우 $590^{\circ}C$에서 완벽한 Tetragonal rutile 형태의 결정성을 보였으며 $SnO_2$:F film $1{\mu}m$ thickness에서 $10({\Omega}/{\square})$ 내외의 우수한 면저항값과 $30(cm^2/Vs)$ 이상의 mobility값을 확인 하였으며, 가시광영역대 에서 높은 투과율과 우수한 haze값을 얻었다.

• Journal of the Korean Vacuum Society
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• v.8 no.3B
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• pp.297-301
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• 1999

High quality CdTe single crystal for the solar cell fabrication was grown by vertical Bridgman method. The etch pits patterns of {111} surfaces of CdTe etched by Nakagawa solution was observed the {11} A composed of Cd atoms with typical triangle etch pits of pyramid mode. From the photoluminescence measurement of {111} A, we observed free exciton $(E_x)$ existing only high quality crystal and neutral acceptor bound exciton ($A^{\circ}$, X) having very strong peak intensity. Then, the full width at half maximum and binding energy of neutral acceptor bound exciton were 7 meV and 5.9 meV, respectively. By Haynes rule, and activation energy of impurity was 59meV. Therefore, the origins on impurity level acting as a neutral acceptor were associated Ag or Cu elements.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.237-242
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• 2001

The stochiometric mix of evaporating materials for the CuGaSe$_2$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, CuGaSe$_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were 610$^{\circ}C$ and 450$^{\circ}C$, respectively The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the CuGaSe$_2$ single crystal thin film, we have found that the values of spin orbit splitting Δ So and the crystal field splitting ΔCr were 91 meV and 249.8 meV at 20 K, respectively. From the Photoluminescence measurement on CuGaSe$_2$ single crystal thin film, we observed free excition (Ex) existing only high quality crystal and neutral bound exiciton (D$^{\circ}$,X) having very strong peak intensity. Then, the full-width-at-half-maximum(FWHM) and binding energy 7f neutral acceptor bound excision were 8 meV and 35.2 meV, respectivity. By Haynes rule, an activation energy of impurity was 355.2 meV

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.277-280
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• 2009

Wind monitoring system is an absolutely-required system for assessing a performance and fatigue load of the wind energy generator in an on-shore wind energy experimental research complex. It was implemented for the purpose of monitoring the wind information measured from a meteorological tower at the monitoring house and of utilizing the measured data for the performance assessment, by using the LabVIEW program. Then, by adding the performance assessment-related data acquired from the wind energy generator during the performance assessment and the data recorder for synchronizing the data of meteorological tower, the system was implemented. Because it transmitted the data by converting the output 'RS-232' of data logger which measures the wind condition into CAN protocol, the data error rate was minimized, This paper is intended to explain the developed wind data monitoring system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.11
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• pp.1126-1131
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• 2008

This paper applies the Orbital Geometry-based Bias Estimation Algorithm to the magnetometer measurement data of KOMPSAT-1 and 2 and analyzes the induced magnetic field bias caused by the solar panels and electronics boxes in spacecraft bus. This paper reveals that the estimation and correction of the induced magnetic field bias copes with the aging process of magnetometer and makes it possible to carry on the satellite mission by extending its lifetime.

• KIEAE Journal
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• v.6 no.1
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• pp.25-32
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• 2006

Regarding to the Domestic housing politics to improve residing environment and effective use of country land, apartment buildings have been constructed since early of 1970s. Now apartment is taking over 50% out of entire housing in Korea. In the view point of PV application to the apartment, PV has amny advantages because of the wideness of out-walls and high floors building in APT. Therefore, if APT could use the electricity produced by BIPV, we can solve more easily environment and energy problems caused by housing. The research conclusion by analysing conditions and application method to introduce BIPV application to APT in near future is as below. -The out look of APT has been developed periodically and recently gable roof or canopy is popular which PV installation is more favorable. -For Balcony part with double skin facade sassy window, It has a preferable condition to install on the wall depending on the window direction. -In case of shorter distance between buildings due to high ratio of outside measurement, it is more desirable to install PV on the roof than on the wall of Apartment by considering low solar altitude. -Also depending on the direction of APT building, it is more effective and productive in electricity in the broad surface of side wall of APT. -In case of superhigh floor APT where facade system is mostly double skin facade of curtain wall system, PV module can replace the traditional curtain wall and will reduce architectural materials and obtain various out look design thereof.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.4
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• pp.139-143
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• 2005

For application of carbon nano-tube (CNT) as a counter electrode materials of dye-sensitized solar cell (DSSC), the electrochemical behavior of CNT electrode was studied, employing cyclic-voltammetry (C-V) and impedance spectroscopy. Fabrication of CNT-paste and formation of CNT-counter electrode for characteristic measurement have been carried out using ball-milling and doctor blade process, respectively. Unit cell for measurements was assembled using Pt electrode, CNT electrode, and iodine-embedded electrolyte. Field emission-scanning electron microscopy (FE-SEM) was used for structural investigation of CNT powder and electrode. Sheet resistance of electrode was measured with 4-point probe method. Electrochemical properties of electrode, C-V and impedance spectrum, were studied, employing potentiogalvanostat (EG&G 273A) and lock in amplifier (EG&G 5210). As a results, the sheet resistance of CNT electrode is almost similar to that of F-doped SnO2 (FTO) coated glass substrate as approximately 10 ohm/sq. From C-V and impedance spectroscopy measurements, it was found that CNT electrode has high reaction rate and low interface reaction resistance between CNT surface and electrolyte. These results provides that CNT electrode were superior to that of conventional Pt electrode. Particularly, the reaction rate in the CNT electrode is about thrice high than Pt electrode. Therefore. CNT electrode is to be good candidate material for counter electrode in DSSC.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.12
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• pp.757-761
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• 2017

The computational fourier-transform moire (CFTM) method has been briefly explained and this method was used to perform strain analysis of a misfit dislocation in a strained $Si/Si_{0.55}Ge_{0.45}$ layer. An essential advantage of the CFTM method is that it does not require unwrapping, such that errors due to improper unwrapping can be excluded. The analysis results revealed that the Si layer was grown with tensile stress on $Si_{0.55}Ge_{0.45}$ and lattice constant of the Si layer along the growth direction was 1.9% smaller than that of $Si_{0.55}Ge_{0.45}$. On the other hand, strain of the misfit dislocation in the strained $Si/Si_{0.55}Ge_{0.45}$ layer was maximum at the dislocation core due to an extra half-plane and the $e_{xx}$ and $e_{yy}$ values were positive and negative, respectively, along the direction of a burgers vector.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.2
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• pp.31-35
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• 2014

The thickness dependent electrical, structural, and optical properties of ZnO films grown by atomic layer deposition (ALD) at various growth temperatures were investigated. In order to deposit ZnO films, diethylzinc and deionized water were used as metal precursor and reactant, respectively. ALD process window was found at the growth temperature range from $150^{\circ}C$ to $250^{\circ}C$ with a growth rate of about $1.7{\AA}/cycle$. The electrical properties were studied by using van der Pauw method with Hall effect measurement. The structural and optical properties of ZnO films were analyzed by using X-ray diffraction, field emission scanning electron microscopy, and UV-visible spectrometry as a function of thickness values of ZnO films, which were selected by the lowest electrical resistivity. Finally, the figure of merit of ZnO films could be estimated as a function of the film thickness. As a result, this investigation of thickness dependent electrical, structural, and optical properties of ZnO films can provide proper information when applying to optoelectronic devices, such as organic light-emitting diodes and solar cells.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.286-292
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• 2012

In recent years, building energy has received much attention and there are many support system to reduce building energy consumption. In addition, It is clear that encouraging to energy efficiency investments can be beneficial to our society, because of the energy supply instability and higher energy price in Korea. Nevertheless, ESCO business, represent the existing building energy retrofit business, hardly has not expanded in Korea. besides, in the case of existing building, it is more difficult to achieve the energy retrofit measures than new building, due to the existing buildings have attributes such as a long life and a lots of energy factor, etc. Therefore, for activate ESCO business and expand ESCO bussiness target to small-to-medium building, it is needed to optimization of retrofitting methods for existing small-to medium buildings in Korea. this research was to derive energy retrofit methods through the energy audit and analysis performed for a small-to-medium building located in Suwon, Korea.