The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Jan Nievendick - One of the best experts on this subject based on the ideXlab platform.
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relation between solar cell efficiency and crystal defect etching induced by acidic texturization on multicrystalline Silicon Material
Solar Energy Materials and Solar Cells, 2012Co-Authors: Floor Souren, Jan Nievendick, Martin Zimmer, Jonas Haunschild, Jochen RentschAbstract:Abstract Acidic texturing of multi crystalline Silicon (mc-Si) wafers often leads to rough surfaces with areas of strong etch attacks which we call trench structures. Particularly at sites containing crystal defects such as grain boundaries and dislocations, trench structures are created. These trench structures have often been reported as detrimental to solar cell performance. In this paper, a detailed statistical analysis of the influence of trench structures on solar cell efficiency is carried out. It is shown that their influence on cell efficiency, as well as open circuit voltage, short circuit current and fill factor, is only very minor. The Material quality determines the diffusion length of the minority carriers and predominantly impacts the solar cell efficiency. Moreover, it has been established that trench structures do not significantly influence surface roughness and do not lead to shunting losses. However, the statistical model indicates that Materials with many crystal defects, and thus lower quality and a smoother (and hence more reflecting) texture lead to slightly higher efficiencies compared to solar cells with a rougher texture. The higher efficiency obtained with smoother textures for this kind of Material might be caused by the absence of trench structures. Furthermore, it has been found in this work that for these acidic textures, surface roughness correlates to weighted reflection and hence only one of these parameters has to be determined to analyze an acidic texture.
Jochen Rentsch - One of the best experts on this subject based on the ideXlab platform.
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relation between solar cell efficiency and crystal defect etching induced by acidic texturization on multicrystalline Silicon Material
Solar Energy Materials and Solar Cells, 2012Co-Authors: Floor Souren, Jan Nievendick, Martin Zimmer, Jonas Haunschild, Jochen RentschAbstract:Abstract Acidic texturing of multi crystalline Silicon (mc-Si) wafers often leads to rough surfaces with areas of strong etch attacks which we call trench structures. Particularly at sites containing crystal defects such as grain boundaries and dislocations, trench structures are created. These trench structures have often been reported as detrimental to solar cell performance. In this paper, a detailed statistical analysis of the influence of trench structures on solar cell efficiency is carried out. It is shown that their influence on cell efficiency, as well as open circuit voltage, short circuit current and fill factor, is only very minor. The Material quality determines the diffusion length of the minority carriers and predominantly impacts the solar cell efficiency. Moreover, it has been established that trench structures do not significantly influence surface roughness and do not lead to shunting losses. However, the statistical model indicates that Materials with many crystal defects, and thus lower quality and a smoother (and hence more reflecting) texture lead to slightly higher efficiencies compared to solar cells with a rougher texture. The higher efficiency obtained with smoother textures for this kind of Material might be caused by the absence of trench structures. Furthermore, it has been found in this work that for these acidic textures, surface roughness correlates to weighted reflection and hence only one of these parameters has to be determined to analyze an acidic texture.
Giso Hahn - One of the best experts on this subject based on the ideXlab platform.
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Improvement of VOC for thin RST solar cells by enhanced back side passivation
Energy Procedia, 2015Co-Authors: Benjamin Albrecht, Philipp Keller, Fabrice De Moro, Giso HahnAbstract:The Ribbon on Sacrificial Template (RST) casting process enables the production of Silicon ribbon wafers below 100 μm thickness for thin solar cells. It is a kerf-loss free direct wafer casting method which means that energy-intensive Silicon Material can be saved. Furthermore, thin solar cells have lower requirement on the charge carrier lifetime because smaller diffusion lengths are sufficient to separate the carriers. For this contribution, an established lab-type PERC solar cell process was applied on
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Hydrogenation in Crystalline Silicon Materials for Photovoltaic Application
Solid State Phenomena, 2009Co-Authors: Giso Hahn, Martin Käs, Bernhard HerzogAbstract:In this contribution an overview of hydrogenation issues for (multi-)crystalline Silicon Material is given. Crystalline Silicon Material for photovoltaic application contains more defects than Material used for other semiconductor device fabrication. Therefore passivation of bulk defects has to be performed to reach higher efficiencies and exploit the cost reduction potential of these Materials. Especially minority charge carrier lifetimes of ribbon Silicon can be drastically improved by hydrogenation in combination with a gettering step. Apart from bulk passivation atomic hydrogen plays an important role in surface passivation via dielectric layers. Performance of single dielectric layers or stack systems can be increased after a hydrogenation step. It is believed that hydrogen can passivate defects at the Silicon/dielectric interface allowing for lower surface recombination velocities. In industrial application hydrogenation is performed via deposition of a hydrogen-rich PECVD SiNx layer followed by a belt furnace annealing step. Surface passivation for characterization of charge carrier bulk lifetime is often performed with the same technique, omitting the annealing step to avoid in-diffusion of hydrogen. It is shown that for some crystalline Silicon Materials even the PECVD SiNx deposition alone (without annealing step) can cause significant bulk defect passivation, which in this case causes an unwanted change of bulk lifetime.
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Texturing techniques and resulting solar cell parameters on tri-Silicon Material
2003Co-Authors: Detlef Sontag, Giso Hahn, Peter Fath, Ernst Bucher, W. KruhlerAbstract:Tri-crystalline Silicon Material (Tri-Si) is a promising alternative to mono-crystalline CZ Silicon because of a faster crystallization process and higher wafer stability. The orientation of the three crystals [110] is different to the [100] orientation in CZ Material typically used in the photovoltaic industry. As a consequence the common alkaline texture technique using KOH or NaOH cannot be applied. For this reason we compared several alternative texturing methods like mechanical grooving and acidic texture etching, which work independently of crystal orientations. Solar cells were processed from these wafers, and an overview of their surface morphology as well as the resulting cell parameters is given. By applying an antireflection coating we reached the highest efficiencies reported on Tri-Si Material.
Floor Souren - One of the best experts on this subject based on the ideXlab platform.
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relation between solar cell efficiency and crystal defect etching induced by acidic texturization on multicrystalline Silicon Material
Solar Energy Materials and Solar Cells, 2012Co-Authors: Floor Souren, Jan Nievendick, Martin Zimmer, Jonas Haunschild, Jochen RentschAbstract:Abstract Acidic texturing of multi crystalline Silicon (mc-Si) wafers often leads to rough surfaces with areas of strong etch attacks which we call trench structures. Particularly at sites containing crystal defects such as grain boundaries and dislocations, trench structures are created. These trench structures have often been reported as detrimental to solar cell performance. In this paper, a detailed statistical analysis of the influence of trench structures on solar cell efficiency is carried out. It is shown that their influence on cell efficiency, as well as open circuit voltage, short circuit current and fill factor, is only very minor. The Material quality determines the diffusion length of the minority carriers and predominantly impacts the solar cell efficiency. Moreover, it has been established that trench structures do not significantly influence surface roughness and do not lead to shunting losses. However, the statistical model indicates that Materials with many crystal defects, and thus lower quality and a smoother (and hence more reflecting) texture lead to slightly higher efficiencies compared to solar cells with a rougher texture. The higher efficiency obtained with smoother textures for this kind of Material might be caused by the absence of trench structures. Furthermore, it has been found in this work that for these acidic textures, surface roughness correlates to weighted reflection and hence only one of these parameters has to be determined to analyze an acidic texture.
Jonas Haunschild - One of the best experts on this subject based on the ideXlab platform.
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relation between solar cell efficiency and crystal defect etching induced by acidic texturization on multicrystalline Silicon Material
Solar Energy Materials and Solar Cells, 2012Co-Authors: Floor Souren, Jan Nievendick, Martin Zimmer, Jonas Haunschild, Jochen RentschAbstract:Abstract Acidic texturing of multi crystalline Silicon (mc-Si) wafers often leads to rough surfaces with areas of strong etch attacks which we call trench structures. Particularly at sites containing crystal defects such as grain boundaries and dislocations, trench structures are created. These trench structures have often been reported as detrimental to solar cell performance. In this paper, a detailed statistical analysis of the influence of trench structures on solar cell efficiency is carried out. It is shown that their influence on cell efficiency, as well as open circuit voltage, short circuit current and fill factor, is only very minor. The Material quality determines the diffusion length of the minority carriers and predominantly impacts the solar cell efficiency. Moreover, it has been established that trench structures do not significantly influence surface roughness and do not lead to shunting losses. However, the statistical model indicates that Materials with many crystal defects, and thus lower quality and a smoother (and hence more reflecting) texture lead to slightly higher efficiencies compared to solar cells with a rougher texture. The higher efficiency obtained with smoother textures for this kind of Material might be caused by the absence of trench structures. Furthermore, it has been found in this work that for these acidic textures, surface roughness correlates to weighted reflection and hence only one of these parameters has to be determined to analyze an acidic texture.