• Journal of the Semiconductor & Display Technology
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• v.13 no.3
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• pp.21-25
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• 2014

The texturing is one of the most important processes for high efficiency crystalline silicon solar cells. The rear side flatness of silicon solar cell is very important for increasing the light reflectance and forming uniform back surface field(BSF) region in manufacturing high efficiency crystalline silicon solar cells. We investigated texturing difference between front and rear side of wafer by texturing of two adhered wafers. As a result, the flatter rear side was obtained by forming less pyramid size compared to the front side and improved reflectance of long wavelength and back surface field(BSF) region were also achieved. Therefore, the texturing of two adhered wafers can be expected to improve the efficiency of silicon solar cells due to increased short circuit current(Isc).

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.239.2-239.2
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• 2016

Numerous studies and approaches have been performed for solar cells to improve their photoelectric conversion efficiencies. Among them, the study for electrode containing transparent conducting oxide (TCO) layers is one of issues as well as for the cell structure based on band theory. In this study, we focused on an interfacial layer between p-type silicon and indium tin oxide (ITO) well-known as TCO materials. According to current-voltage characteristics for the sample with the interfacial layers, the improvement of band alignment between p-type silicon and ITO was observed, and their ohmic properties were enhanced in the proper condition of deposition. To investigate cause of this improvement, spectroscopic ellipsometry and ultraviolet photoelectron spectroscopy were utilized. Using these techniques, band alignment and defect in the band gap were examined. The major materials of the interfacial layer are vanadium oxide and tungsten oxide, which are notable as a hole transfer layer in the organic solar cells. Finally, the interfacial layer was applied to silicon solar cells to see the actual behavior of carriers in the solar cells. In the case of vanadium oxide, we found 10% of improvement of photoelectric conversion efficiencies, compared to solar cells without interfacial layers.

• Journal of the Korean institute of surface engineering
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• v.51 no.3
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• pp.185-190
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• 2018

Dopant-free silicon heterojunction solar cells using Transition Metal Oxide(TMO) such as Molybdenum Oxide($MoO_X$) and Vanadium Oxide($V_2O_X$) have been focused on to increase the work function of TMO in order to maximize the work function difference between TMO and n-Si for a high-efficiency solar cell. One another way to increase the work function difference is to control the silicon wafer resistivity. In this paper, dopant-free silicon heterojunction solar cells were fabricated using the wafer with the various resistivity and analyzed to understand the effect of n-Si work function. As a result, it is shown that the high passivation and junction quality when $V_2O_X$ deposited on the wafer with low work function compared to the high work function wafer, inducing the increase of higher collection probability, especially at long wavelength region. the solar cell efficiency of 15.28% was measured in low work function wafer, which is 34% higher value than the high work function solar cells.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.257.2-257.2
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• 2015

In this paper, we report on the 10.33% efficient thin film/bulk tandem solar cells with the top cell made of amorphous silicon thin film and p-type bulk crystalline silicon bottom cell. The tunneling junction layers were used the doped nanocrystalline Si layers. It has to allow an ohmic and low resistive connection. For player and n-layer, crystalline volume fraction is ~86%, ~88% and dark conductivity is $3.28{\times}10-2S/cm$, $3.03{\times}10-1S/cm$, respectively. Optimization of the tunneling junction results in fill factor of 66.16 % and open circuit voltage of 1.39 V. The open circuit voltage was closed to the sum of those of the sub-cells. This tandem structure could enable the effective development of a new concept of high-efficiency and low cost cells.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.176-180
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• 2003

Tri-crystalline silicon (Tri-Si) wafers have three different orientations and three grain boundaries. In this paper, tri-Si wafers have been used for the fabrication of buried contact solar cells. The optical and micro-structural properties of these cells after texturing in KOH solution have been investigated and compared with those of cast multi-crystalline silicon (multi-Si) wafers. We employed a cost effective fabrication process and achieved buried contact solar cell (BCSC) energy conversion efficiencies up to 15% whereas the cast multi-Si wafer has efficiency around 14%.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.5
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• pp.851-856
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• 2017

Research on the edge isolation process of typical polycrystalline silicon solar cells was carried out using laser scribing equipment. The voltage-current characteristics of the solar cell before and after laser scribing were analyzed using a solar simulator. Current density and efficiency increased as the fill factor of the solar cell remained constant after the laser scribing process. The efficiency of the solar cell can be increased in a short time by the edge isolation process performed via a laser scribing process. The polycrystalline silicon solar cell was made into a series electrode, and the efficiency of the solar cell increased because the width of the solar cell was narrowed and the active region was widened by the laser scribing process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.223-224
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• 2008

Important element are low cost, high-efficiency crystalline silicon solar cells. in this paper, Will be able to contribute in low cost, high-efficiency silicon solar cells, Applies oxide/nitride passivation, produced screen-printed solar cells. and the Measures efficiency, and evaluated a justice quality oxide/nitride passivation screen-printed solar cells.

• Current Photovoltaic Research
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• v.5 no.4
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• pp.113-121
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• 2017

The researches on the silicon-based thin films are being actively carried out. The silicon-based thin films can be made as amorphous, microcrystalline and mixed phase and it is known that the optical bandgap can be controlled accordingly. They are suitable materials for the fabrication of single junction, tandem and triple junction solar cells. It can be used as a doping layer through the bonding of boron and phosphorus. The carbon and oxygen can bond with silicon to form a wide range of optical gap. Also, The optical gap of hydrogenated amorphous silicon germanium can be lower than that of silicon. By controlling the optical gaps, it is possible to fabricate multi-junction thin film silicon solar cells with high efficiencies which can be promising photovoltaic devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.7
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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.