• 한국태양에너지학회 논문집
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• 제33권2호
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• pp.11-17
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• 2013

Silicon nitride($SiN_x:H$) deposited by radio frequency plasma enhanced chemical vapor deposition(RF-PECVD) is commonly used for anti-reflection coating and passivation in crystalline silicon solar cell fabrication. In this paper, characteristics of the deposited silicon nitride was studied with change of working pressure, deposition temperature, gas ratio of $NH_3$ and $SiH_4$, and RF power during deposition. The deposition rate, refractive index and effective lifetime were analyzed. The (100) p-type silicon wafers with one-side polished, $660-690{\mu}m$, and resistivity $1-10{\Omega}{\cdot}cm$ were used. As a result, when the working pressure increased, the deposition rate of SiNx was increased while the effective life time for the $SiN_x$-deposited wafer was decreased. The result regarding deposition temperature, gas ratio and RF power changes would be explained in detail below. In this paper, the optimized condition in silicon nitride deposition for silicon solar cell was obtained as 1.0 Torr for the working pressure, $400^{\circ}C$ for deposition temperature, 500 W for RF power and 0.88 for $NH_3/SiH_4$ gas ratio. The silicon nitride layer deposited in this condition showed the effective life time of > $1400{\mu}s$ and the surface recombination rate of 25 cm/s. The crystalline silicon solar cell fabricated with this SiNx coating showed 18.1% conversion efficiency.

• 한국진공학회지
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• 제19권4호
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• pp.314-318
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• 2010

다결정 실리콘 웨이퍼 표면에 대면적 reactive ion etching (RIE) 장비로 표면 텍스쳐를 형성한 뒤 태양전지를 제작하였다. 웨이퍼 표면에 텍스쳐를 형성하는 것은 광학적 손실을 줄이기 위해 일반적으로 사용되는 방법으로 alkaline etching이 사용된다. 그러나 다결정 실리콘 태양전지의 경우 재료의 결정 방향에 따라 식각되는 alkaline etching은 텍스쳐링의 모양을 제어할 수 없어 효과적이지 못하다. 이와 달리 플라즈마 식각방법을 사용하면 표면 텍스쳐의 모양을 효과적으로 제어하여 조금 더 낮은 반사율을 얻을 수 있다. 하지만 텍스쳐 모양 조절로 얻은 낮은 반사율이 항상 높은 변환효율을 얻을 수 있는 것은 아니다. 본 연구에서는 대면적 RIE 공정 조건별로 얻은 태양전지 표면 텍스쳐의 모양에 따라 각각의 반사율과 양자효율 및 변환효율이 미치는 영향을 살펴보았다.

• 천문학회지
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• 제34권4호
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• pp.317-319
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• 2001

The response of the earth's magnetosphere to the variation of the solar wind parameters and Interplanetary magnetic field (IMF) has been stud}ed by using a high-resolution, three-dimension magnetohydrodynamic (MHD) simulation when the WIND data of velocity Vx, plasma density, dynamic pressure, By and Bz every 1 minute were used as input. Large electrojet and magnetic storm which occurred on October 21 and 22 are reproduced in the simulation (fig. 1). We have studied the energy transfer and tail reconnect ion in association with geomagnetic storms.

• 천문학회보
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• 제46권2호
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• pp.47.2-47.2
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• 2021

The present study is focused on origins of the flow and magnetic structure involved in the formation and eruption of a solar prominence. To clarify them, we performed an MHD simulation based on the 3-dimensional emerging flux tube (3DEFT) model, in which self-consistent evolution of a flow and magnetic field passing freely through the solar surface was obtained by seamlessly connecting subsurface dynamics with surface dynamics. By analyzing Lagrangian displacements of magnetized plasma elements, we demonstrate the flow structure which is naturally incorporated to the magnetic structure of the prominence formed via dynamic interaction between the flow and magnetic field.

• 천문학회보
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• 제40권1호
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• pp.85.1-85.1
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• 2015

We investigate the mass and energy of erupting plasma observed in X-rays and EUV, which is associated with a coronal mass ejection (CME) and an X-class flare. The erupting plasma was observed by both the X-ray telescope (XRT) on Hinode and the Atmospheric Imaging Assembly (AIA) on Solar Dynamic Observatory (SDO). We estimate the emission measures of the erupting plasma using a differential emission measure method. The plasma erupts with a loop-like structure in X-ray and EUV. We estimate the mass of erupting plasma assuming a cylinder structure. In addition, we estimate the radiative loss, thermal conduction, thermal, and kinetic energies of the eruptive hot plasma. We find that the thermal conduction timescale is much shorter than the duration of the eruption. This result implies that additional heating during the eruption may be required to explain the hot plasma observations in X-rays.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.430.2-430.2
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• 2016

The front transparent conductive oxide (TCO) films in thin fill solar cell should exhibit high transparency, conductivity, good surface morphology and excellent light scattering properties. The light trapping phenomenon is limited due to random surface structure of TCO films. The proper control of surface structure and uniform cauliflower TCO films may be appropriate for efficient light trapping. We report light trapping scheme of ICP-RIE glass texturing by SF6/Ar plasma for high roughness and haze ratio of ITO films. It was observed that the variation of etching time, pattern size and Ar flow ratio during ICP-RIE process were important factors to improve the diffused transmittance and haze ratio of textured glass. The ICP-RIE textured glass showed low etching rates due to the presence of metal elements like Al, B, F and Na. The ITO films deposited on textured glass substrates showed the high RMS roughness and haze ratio in the visible wavelength region. The change in surface morphology showed negligible influence on electrical and structural properties of ITO films. The ITO films with high roughness and haze ratio can be used to improve the performance of thin film solar cells.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.187-191
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• 2006

Sputter deposition followed by surface treatment was studied using reactive RF plasma as a method for preparing titanium oxide $(TiO_2)$ films on the FTO $(SnO_2: F)$ substrate for dye-sensitized solar cells (DSCs). Anatase structure $TiO_2$ films deposited by reactive RF magnetron sputtering under the conditions of $Ar/O_2(5%)$ mixtures, RF power of 600W and substrate temperature of $400^{\circ}C$ were surface-treated by inductive coupled plasma (ICP) with $Ar/O_2$ mixtures at substrate temperature of $400^{\circ}C$, and thus the films were applied to the DSCs. We have chosen a solar cell width as a variable of a large-scaled DSCs and confirmed electric characteristics of an individual cell. As a result, the higher the internal resistance of DSC becomes, the wider the width gets. Internal resistance makes it difficult to collect photoelectron generated from dye. Ultimately up sizing DSC causes the increase of internal resistance and then has a bad effect on the cell characteristics.

• Journal of Astronomy and Space Sciences
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• 제32권2호
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• pp.101-112
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• 2015

Magnetic reconnection is a fundamental process occurring in a wide range of astrophysical, heliospheric and laboratory plasmas. This process alters magnetic topology and triggers rapid conversion of magnetic energy into thermal heating and nonthermal particle acceleration. Efforts to understand the physics of magnetic reconnection have been made across multiple disciplines using remote observations of solar flares and in-situ measurements of geomagnetic storms and substorms as well as laboratory and numerical experiments. This review focuses on the progress achieved with solar flare observations in which most reconnection-related signatures could be resolved in both space and time. The emphasis is on various observable emission features in the low solar atmosphere which manifest the coronal magnetic reconnection because these two regions are magnetically connected to each other. The research and application perspectives of solar magnetic reconnection are briefly discussed and compared with those in other plasma environments.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.964-967
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• 2002

The effectiveness of silicon nitride SiNx surface passivation is investigated and quantified. This study adopted single-layer antireflection (SLAR) coating of SiNx for efficiency improvement of solar cell. The silicon nitride films were deposited by means of plasma enhanced chemical vapor deposition (PECVD) in planar coil reactor. The process gases used were pure ammonia and a mixture of silane and helium. The thickness and the refractive index on the films were measured by ellipsometry and chemical bonds were determined by using an FT-IR equipment. This films obtained were analyzed in term of hydrogen content, refractive index for gas flow ratio $(NH_3/SiH_4)$, and efficiency of solar cell. The polycrystalline silicon solar cells passivated by silicon nitride shows efficiency above 12.8%.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.145-145
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• 2011

Recently, multi-hole electrode RF capacitively coupled plasma discharge is being used in the deposition of microcrystalline silicon for thin film solar cell to increase the speed of deposition. To make efficient multi-hole electrode RF capacitively coupled plasma discharge, the hole diameter is to be designed concerning the plasma parameters. In past studies, the relationship between plasma parameters such as pressures and gas species, and hole diameter for efficient plasma density enhancement is experimentally shown. In the presentation, the relationship between plasma deriving frequency and hole diameter for efficient multi-hole electrode RF capacitively coupled plasma discharge is shown. In usual capacitively coupled plasma discharge, plasma parameter, such as plasma density, plasma impedence and plasma temperature, change as frequency increases. Because of the change, the optimum hole diameter of the multi-hole electrode RF capacitively coupled plasma for high density plasma is thought to be modified when the plasma deriving frequency changes. To see the frequency effect on the multi-hole RF capacitively coupled plasma is discharged and one of its electrode is changed from a plane electrode to a variety of multi-hole electrodes with different hole diameters. The discharge is derived by RF power source with various frequency and the plasma parameter is measured with RF compensated single Langmuir probe. The shrinkage of the hole diameter for efficient discharge is observed as the plasma deriving frequency increases.