• 한국전기전자재료학회논문지
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• 제22권7호
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• pp.616-621
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• 2009

Reduction of optical losses in crystalline silicon solar cells by surface modification is one of the most important issues of silicon photovoltaics. Porous Si layers on the front surface of textured Si substrates have been investigated with the aim of improving the optical losses of the solar cells, because an anti-reflection coating(ARC) and a surface passivation can be obtained simultaneously in one process. We have demonstrated the feasibility of a very efficient porous Si ARC layer, prepared by a simple, cost effective, electrochemical etching method. Silicon p-type CZ (100) oriented wafers were textured by anisotropic etching in sodium carbonate solution. Then, the porous Si layers were formed by electrochemical etching in HF solutions. After that, the properties of porous Si in terms of morphology, structure and reflectance are summarized. The structure of porous Si layers was investigated with SEM. The formation of a nanoporous Si layer about 100nm thick on the textured silicon wafer result in a reflectance lower than 5% in the wavelength region from 500 to 900nm. Such a surface modification allows improving the Si solar cell characteristics. An efficiency of 13.4% is achieved on a monocrystalline silicon solar cell using the electrochemical technique.

• Current Photovoltaic Research
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• 제6권1호
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• pp.27-30
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• 2018

The dependency of the electrical characteristics of silicon solar-cells on the depth of damaged layer induced by wire-sawing process was investigated. To compare cell efficiency with residual sawing damage, silicon solar-cells were fabricated by using as-sawn wafers having different depth of saw damage without any damaged etching process. The damaged layer induced by wire-sawing process in silicon bulk intensely influenced the value of fill factor on solar cells, degrading fill factor to 57.20%. In addition, the photovoltaic characteristics of solar cells applying texturing process shows that although the initial depth of saw-damage induced by wire-sawing process was different, the value of short-circuit current, fill-factor, and power-conversion-efficiency have an almost same, showing ~17.4% of cell efficiency. It indicated that the degradation of solar-cell efficiency induced by wire-sawing process could be prevented by eliminating all damaged layer through sufficient pyramid-surface texturing process.

• 전기학회논문지
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• 제65권10호
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• pp.1702-1705
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• 2016

We propose a novel hydrogen-reduced p-type amorphous silicon oxide buffer layer between $TiO_2$ antireflection layer and p-type silicon window layer of silicon thin film solar cells. This new buffer layer can protect underlying the $TiO_2$ by suppressing hydrogen plasma, which could be made by excluding $H_2$ gas introduction during plasma deposition. Amorphous silicon oxide thin film solar cells with employing the new buffer layer exhibited better conversion efficiency (8.10 %) compared with the standard cell (7.88 %) without the buffer layer. This new buffer layer can be processed in the same p-chamber with in-situ mode before depositing main p-type amorphous silicon oxide window layer. Comparing with state-of-the-art buffer layer of AZO/p-nc-SiOx:H, our new buffer layer can be processed with cost-effective, much simple process based on similar device performances.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.250-253
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• 2007

An evaporated Ti/Pd/Ag contact system is most widely used to make high-efficiency silicon solar cells, however, the system is not cost effective due to expensive materials and vacuum techniques. Commercial solar cells with screen-printed contacts formed by using Ag paste suffer from a low fill factor and a high shading loss because of high contact resistance and low aspect ratio. Low-cost Ni and Cu metal contacts have been formed by using electroless plating and electroplating techniques to replace the Ti/Pd/Ag and screen-printed Ag contacts. Ni/Cu alloy is plated on a silicon substrate by electro-deposition of the alloy from an acetate electrolyte solution, and nickel-silicide formation at the interface between the silicon and the nickel enhances stability and reduces the contact resistance. It was, therefore, found that nickel-silicide was suitable for high-efficiency solar cell applications. The Ni contact was formed on the front grid pattern by electroless plating followed by anneal ing at $380{\sim}400^{\circ}C$ for $15{\sim}30$ min at $N_{2}$ gas to allow formation of a nickel-silicide in a tube furnace or a rapid thermal processing(RTP) chamber because nickel is transformed to NiSi at $380{\sim}400^{\circ}C$. The Ni plating solution is composed of a mixture of $NiCl_{2}$ as a main nickel source. Cu was electroplated on the Ni layer by using a light induced plating method. The Cu electroplating solution was made up of a commercially available acid sulfate bath and additives to reduce the stress of the copper layer. The Ni/Cu contact was found to be well suited for high-efficiency solar cells and was successfully formed by using electroless plating and electroplating, which are more cost effective than vacuum evaporation. In this paper, we investigated low-cost Ni/Cu contact formation by electroless and electroplating for crystalline silicon solar cells.

• 태양에너지
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• 제7권1호
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• pp.30-34
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• 1987

Experimental results are discussed concerning temperature effects from $25^{\circ}C$ to $100^{\circ}C$ on amorphous silicon solar cells. N-I-P hydrogenated amorphous silicon solar cells are fabricated on stainless steel and indium tin oxide glass substrates. The open circuit voltage, short circuit current, fill factor and conversion efficiency have been measured under AM1 condition as a function of temperature. The open circuit voltage decreased by $2.6mV/^{\circ}C$ while the short circuit current increases with increased temperature. The conversion efficiency is almost independent of temperature which is contrary to widely using single crystalline solar cells of which efficiencies decrease with increasing temperature.

• 대한전기학회논문지
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• 제33권6호
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• pp.203-211
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• 1984

MOS silicon solar cells have been developed using the fixed (interface) charge inherent to thermally oxidized silicon to induce an n-type inversion layer in 1-10 ohm-cm p-type silicon. Higher collection efficiencies are predicted than for diffused junction cells. Without special precautions a conversion efficiency of 14.2% is obtained. A MOS silicon solar cell is described in which an inversion layer forms the active area which is then contacted by means of a MOS grid. The highest efficiency is obtained when the resistivity of the substrate is high.

• Korean Chemical Engineering Research
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• 제46권1호
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• pp.37-49
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• 2008

태양전지 기판의 원료인 폴리실리콘의 공급부족은 태양광발전산업의 비약적인 발전에 있어 최대 걸림돌이 되고 있다. 태양전지 제조에 충분한 순도로 폴리실리콘을 값싸게 제조할 수 있게 하는 공정기술의 개발은 태양광발전의 가격 경쟁력과 활용범위를 크게 증가시키는 중요한 계기가 될 수 있다. 본 총설에서는 태양전지용 폴리실리콘 제조를 위해 현재 이용 가능한 기술들을 정리해보고, 최근에 주목받고 있는 유동층 석출공정기술과 관련하여 응용범위 확대를 가로막고 있는 주요 기술적 장애요인에 대하여 중점적으로 소개하고자 한다.

• 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%.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.89-93
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• 2005

A rear contact solar cell has a potential merit of efficiency improvement by a low shading loss in front surface. a simplified module assembly. and a higher packing density. Among the rear contact solar cells. MWT. metallizationl wrap through MWT solar cells that have the bus bars on the back side and the front side metallization is connected to the back through metal filled laser fired holes in the silicon wafer. This approach has the advantages of a much more uniform appearance. The first fabrication of MWT using a multicrystalline silicon modules in our group showed $12.28\%$ on $125mm{\times}125mm$ active area.

• 반도체디스플레이기술학회지
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• 제12권3호
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• pp.47-51
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• 2013

Current research trends of solar cells has focused on the high conversion efficiency and low-cost production technology. Passivation technology that can be easily adapted to mass production. Therefore, this study conducted experiments with aim of the following two methods for the fabrication of high-efficiency crystalline silicon solar cells. In the first task, an attempt is formation of local Al-BSF to a number of locally doped dots to increase the conversion efficiency of solar cells to reduce the loss of $V_{oc}$ overcome. The second major task, rear surface apply in $Al_2O_3/SiN_x$ stack layer, $Al_2O_3$ prominent negative fixed charge characteristics. As the result of task, Local Al-BSF and $Al_2O_3/SiN_x$ stack layer applied to the p-type single crystalline silicon solar cells, the average $V_{oc}$ of 644mV, $I_{sc}$ of 918mV and conversion efficiency of 18.70% were obtained.