• Current Photovoltaic Research
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• v.5 no.2
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• pp.63-67
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• 2017

Aluminum oxide ($Al_2O_3$) film deposited by atomic layer deposition (ALD) is known to supply excellent surface passivation properties on crystalline Si surface. The quality of passivation layer is important for high-efficiency silicon solar cell. double-layer structures have many advantages over single-layer materials. $Al_2O_3/SiN_X$ passivation stacks have been widely adopted for high- efficiency silicon solar cells. The first layer, $Al_2O_3$, passivates the surface, while $SiN_X$ acts as a hydrogen source that saturates silicon dangling bonds during annealing treatment. We explored the properties on passivation film of $Al_2O_3/SiN_X$ stack layer with changing the conditions. For the post annealing temperature, it was found that $500^{\circ}C$ is the most suitable temperature to improvement surface passivation.

• Composites Research
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• v.24 no.6
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• pp.56-63
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• 2011

The objective of this study is to investigate appropriate bonding methods of solar cells in order to apply solar cells, which have been receiving particular attention as a renewable energy due to fossil energy depletion and environment issues, to composite structures. Back-contact solar cells with approximately 24.2% energy conversion efficiency were used in this study. Since silicon-based solar cells are mechanically fragile, the secondary-bonding methods using adhesive were examined in this study. The experiment was conducted with three kinds of bonding materials such as EVA film, Resin film and elastic adhesive. The performance of solar cells for three types of adhesives under mechanical loading on test specimens is conducted. In addition, the measuring equipment was designed to evaluate the performance of the solar cells under mechanical loading in real time and the fracture characteristics depending on bonding materials were evaluated. The reason decreasing solar cells efficiency were analyzed and considered by Fractography. The results show that the solar cell performance is largely affected by bonding techniques. Moreover, the bonding method using elastic adhesive shows best solar cell efficiency.

• Current Photovoltaic Research
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• v.6 no.2
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• pp.49-55
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• 2018

Recently solar cell industry needs the optimal design of Czochralski process for low cost high quality silicon mono crystalline ingot. Because market needs both high efficient solar cell and similar cost with multi-crystalline Si ingot. For cost reduction in Czochralski process, first of all energy reduction should be completed because Czochralski process is high energy consumption process. For this purpose we studied optimal water-cooling tube design and simultaneously we also check the quality of ingot with Von mises stress and V(pull speed of ingot)/G(temperature gradient to the crystallization) values. At this research we used $CG-Sim^{(R)}$ S/W package and finally we got improved water-cooling tube design than normally used process in present industry. The optimal water-cooling tube length should be 200mm. The result will be adopted at real industry.

• Journal of the Speleological Society of Korea
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• no.82
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• pp.5-7
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• 2007

In this paper, p-n junction formation using screen-printed metalization and co-firing is used to fabricate high-efficiency solar cells on single- crystalline silicon substrates. In order to form high-quality contacts, co-firing of a screen-printed Ag grid on the front and Al on the back surface field is implemented. These contacts require low contact resistance, high conductivity, and good adhesion to achieve high efficiency. Before co-firing, a statistically designed experiment is conducted. After the experiment, a neural network (NN) trained by the error back-propagation algorithm is employed to model the crucial relationships between several input factors and solar cell efficiency. The trained NN model is also used to optimize the beltline furnace process through genetic algorithms.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.85-88
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• 2004

Mono-crystalline silicon(mono-Si) is both abundant in our environment and an excellent material for Si device applications. However, single crystalline silicon solar cell has been considered to be expensive for terrestrial applications. For that reason, the last few years have seen very rapid progress in the research and development activities of layer transfer(LT) processes. Thin film Si layers which can be detached from a reusable mono-Si wafers served as a substrate for epitaxial growth. The epitaxial films have a very high efficiency potential. LT technology is a promising approach to reduce fabrication cost with high efficiency at large scale since expensive Si substrate can be recycled. Low quality Si can be used as a substrate. Therefore, we propose one of the major technologies on fabricating thin film Si substrate using a LT. In this paper, we study the LT method using the electrochemical etching(ECE) and solid edge.

• Current Photovoltaic Research
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• v.9 no.1
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• pp.17-21
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• 2021

In this study, the effect of water level and temperature on the power generation was investigated in a water tank with an aquavoltaic PV module to perform feasibility research for the development of salt farm aquavoltaic system. The silicon solar cell attached to the bottom of each water tank is a 1-cell mini module, and the underwater effects of the crystal phase (19.0~19.9% of single- & 17.9~19.9% of poly-crystalline) of the PV module were investigated, and power generation characteristics for water level (0~10 cm) and temperature (10~40℃) were analyzed. The deterioration coefficients according to the water level and temperature of each single- and poly-crystalline module were investigated at very similar levels such as, -2.01 %/cm and -2.02 %/cm, -0.50 %/℃ and -0.48 %/℃, respectively. Therefore, in salt farm aquavoltaic system, water levels need to maintain as low as possible, and heat-induced degradation is similar to those shown in general land, and no factors have been found to be affected by the underwater environment depending on the determination.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.153-154
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• 2007

결정질 실리콘 웨이퍼의 두께와 비저항은 태양전지의 효율을 결정하는 매우 중요한 요인이다. 높은 효율을 갖는 태양전지 설계를 위해 태양전지 시뮬레이터인 PC1D 프로그램을 이용하여 태양전지 웨이퍼 두께, 웨이퍼 비저항, 에미터 도핑 농도를 조절하였다. 최적화 결과, 베이스층 두께 $100{\mu}m$, 비저항 $0.1{\Omega}{\cdot}cm$, 에미터층 도핑 농도 $3{\cdot}10^{18}cm^{-3}$에서 $J_{sc}=39(mA/cm^2),\;V_{oc}=734(mV),\;P_{max}=3.17(W)$, FF=74, Efficiency=21.3%의 고효율을 얻을 수 있다. 본 연구를 통하여 태양전지 설계나 제조 시에 연구비를 절감할 수 있고 높은 효율의 태양전지로 접근할 수 있다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.57-58
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• 2007

결정질 실리콘 웨이퍼의 텍스쳐링과 도핑은 태양전지의 효율을 결정하는 매우 중요한 요인이다. 높은 효율을 갖는 태양전지 설계를 위해 PC1D를 이용하여 텍스쳐링 사면체의 폭 및 각도, 베이스 면저항 및 농도를 조절하였다. 최적화 결과, 텍스쳐 피라미드의 폭은 $2{\sim}4{\mu}m$, 각도는 $79^{\circ}$ 베이스 면저항 $100{\Omega}/{\Box}$, 도핑 농도 $1{\times}10^{19}cm^{-3}$에서 15.06%의 변환효율을 얻을 수 있다.

• New & Renewable Energy
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• v.5 no.1
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• pp.26-31
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• 2009

The surface etching characteristics of single crystalline silicon wafer were investigated using potassium hydroxide (KOH) and tetramethylammonium hydroxide (TMAH). The saw damage layer was removed after 10min by KOH 45wt% solution at $80^{\circ}C$. The wafer etched at high temperature ($90^{\circ}C$) and in low concentration (4wt%) of TMAH solution showed an increased etch rate of silicon wafer and wavy patterns on the surface. Especially, pyramidal textures were formed in 4wt% TMAH solution without alcohol additives.

• Journal of Sensor Science and Technology
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• v.20 no.3
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• pp.207-212
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• 2011

In this study, pyramid structured black silicon process was developed in order to overcome disadvantages of using wet etching to texture the surface of single crystalline silicon and using grass/needle-like black silicon structure. In order to form the pyramidal black silicon structure on the silicon surface, the RIE system was modified to equip with metal-mesh on the top of head shower. The process conditions were : $SF_6/O_2$ gas flow 15/15 sccm, RF power of 200 W, pressure at 50 mTorr ~ 200 mTorr, and temperature at $5^{\circ}C$. The pressure did not affect the pyramid structure significantly. Increasing processing time increased the size of the pyramid, however, the size remained constant at 1 ${\mu}M$ ~ 2 ${\mu}M$ between 15 minutes ~ 20 minutes of processing. Pyramid structure of 1 ${\mu}M$ in size showed to have the lowest reflectivity of 7 % ~ 10 %. Also, the pyramid structure black silicon is more appropriate than the grass/needle-like black silicon when creating solar cells.