• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.355-358
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• 2009

This paper presents the technology of selective emitter for high efficiency crystalline silicon solar cell. The effect of selective emitter is analyzed by using the simulation program for solar cell, PC1D. The selective emitter shows better spectral response in short wavelength regions compared to homogeneous emitter. Therefore, the efficiency of solar cell with selective emitter can be improved by changing the sheet resistance from 60 $\Omega/\square$ to 120 $\Omega/\square$. In addition, the power loss of solar cell can be minimized by optimizing width and gap of the finger electrodes on the selective emitter.

• Journal of the Korean Solar Energy Society
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• v.32 no.5
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• pp.102-107
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• 2012

Halogen lamp was applied to fabricate the selective emitter crystalline silicon solar cell. In selective emitter structure, the recombination of minority carriers is reduced with heavily doped emitter under metal grid, consequently improving the conversion efficiency. Laser selective emitter process which is recently used the most generally induces the damage on the silicon surface. However the lamp has enough heat to form heavily doped emitter layer by diffusing phosphorus from PSG without surface damage. In this work, we have studied to find the design and the suitable condition for halogen lamp such as power, time, temperature and figured out the possibility to fabricate the selective emitter silicon solar cell by lamp heating. The sheet resistance with $100{\Omega}/{\Box}$ was lower to $50{\Omega}/{\Box}$ after halogen lamp treatment. Heat transfer to lightly doped emitter region was blocked by using the shadow mask.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.56-59
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• 2011

The process conditions for high efficiency industrial crystalline Si solar cells with selective emitter were optimized. In the screen printed solar cells, the sheet resistance must be 50-60V/sq. because of metal contact resistance. But the low sheet resistance causes the increase of the recombination and blue response at the short wavelength. Therefore, the screen printed solar cells with homogeneous emitter have limitations of efficiency, and this means that the selective emitter must be used to improve cell efficiency. This work demonstrates the feasibility of a commercially available selective emitter process, based on screen printing and conventional diffusion process. Now, we improved cell efficiency from 18.29% to18.45% by transition of heavy emitter pattern and shallow emitter doping condition.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.12
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• pp.1010-1017
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• 2011

The use of plated front contact for metallization of silicon solar cell may alternative technologies as a screen printed and silver paste contact. This technologies should allow the formation of contact with low contact resistivity a high line conductivity and also reduction of shading losses. A selective emitter structure with highly dopes regions underneath the metal contacts, is widely known to be one of the most promising high-efficiency solution in solar cell processing. When fabricated Ni/Cu plating metallization cell with a selective emitter structure, it has been shown that efficiencies of up to 18% have been achieved using this technology.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.393-393
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• 2011

오늘 날 태양전지 산업에서 가장 많은 생산을 하고 있는 분야는 결정질 태양전지분야이다. 현재는 이러한 시대적 요구에 따라 많은 연구가 진행되고 있는데 특히 junction을 이루는 n layer의 doping profile을 선택적으로 형성하여 개방전압 및 단락전류를 향상시키는 연구가 활발히 진행되고 있다. 본 연구는 이러한 n type layer의 doping profile을 선택적으로 형성하는 selective emitter solar cell에 관한 연구로써 SILVACO simulation을 이용하여 low Rs 영역은 고정하고 high Rs 영역의 doping depth를 가변 함으로써 high Rs 영역을 달리 형성하는 방법으로 selective emitter solar cell의 high Rs영역의 최적화에 관한 전산모사를 실시하였다. 각각의 가변조건에 따라 quantum efficiency를 통한 광학적 분석과 I-V를 통한 전기적 분석을 하여 high Rs영역을 최적화 하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.234-234
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• 2010

Most high efficiency silicon solar cells use a passivated selective emitter. It have been an important research subject for crystalline silicon solar cells for decades. It is being used in production for high efficiency solar cells. Most of the selective emitter process require expensive extra masking, etching steps, and a double diffusion process making selective emitters not cost effective. In this paper, we study method for single diffusion step selective emitter process as an alternative to not cost effective double diffusion process. Cost effective selective emitter that the efficiency should be increased significantly (mare than 0.2%) and that the process should simple, robust and cheap.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.91.2-91.2
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• 2010

The use of plated front contact for metallization of silicon solar cell may alternative technologies as a screen printed and silver paste contact. This technologies should allow the formation of contact with low contact resistivity a high line conductivity and also reduction of shading losses. The better performance of Ni/Cu contacts is attributed to the reduced series resistance due to better contact conductivity of Ni with Si and subsequent electroplating of Cu on Ni. The ability to pattern narrower grid lines for reduced light shading combined with the lower resistance of a metal silicide contact and improved conductivity of plated deposit. This improves the FF as the series resistance is deduced. This is very much required in the case of low concentrator solar cells in which the series resistance is one of the important and dominant parameter that affect the cell performance. A selective emitter structure with highly dopes regions underneath the metal contacts, is widely known to be one of the most promising high-efficiency solution in solar cell processing. This paper using selective emitter structure technique, fabricated Ni/Cu plating metallization cell with a cell efficiency of 17.19%.

• Current Photovoltaic Research
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• v.2 no.3
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• pp.130-134
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• 2014

We have fabricated the selective emitter solar cell using double textured nanowires structure. The $40{\times}40mm2$-sized silicon substrates were textured to form the pyramid-shaped surface and the nanowires were fabricated by metal assisted chemical etching process using Ag nanoparticles, subsequently. The heavily doped and shallow emitters for selectiv eemitter solar cells were prepared through the thermal $POCl_3$ diffusion and chemical etch-back process, respectively. The front and rear electrodes were prepared following conventional screen printing method and the widths of fingers have been optimized. The selective emitter solar cell using double textured nanowires structure achieved a conversion efficiency of 17.9% with improved absorption and short circuit current density.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.454-455
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• 2009

Selective emitter structure have an important research subject for crystalline silicon solar cells because it is used in production for high efficiency solar cells. A selective emitter structure with highly doped regions underneath the metal contacts is widely known to be one of the most promising high-efficiency solution in solar cell processing. Since most of the selective emitter processes require expensive extra masking and double steps process. Formation of selective emitters is not cost effective. One method that satisfies these requirements is the method of screen-printing with a phosphorus doping paste. In this paper we researched two groups of selective emitter structure process. One was using dopant paste, and the other was using solid source, in order to compare their uniformity, sheet resistance and performance condition time.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.40-44
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• 2011

Recent studies in crystalline silicon solar cell fabrication have been focused on high efficiency and low cost. However, the rising of the cost results in additional processes to approach high efficiency. The fabrication process also becomes complicated with additional technologies. In this paper, we studied the selective emitter formation with phosphorous paste to improve the conversion efficiency. Selective emitter formations like two-step diffusion or etch-back method require at least one more step compared in the conventional line since heavily and lightly doped area was needed to form separately.However,one-step diffusion process is the method diffusing heavily and lightly doped area at the same time only with additional screen-printing step. This study lays the foundation for the simple way to form the selective emitter.