Veröffentlichungen
2017 |
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M. Rienäcker, M. Bossmeyer, A. Merkle, U. Römer, F. Haase, J. Krügener, R. Brendel, and R. Peibst IEEE Journal of Photovoltaics 7 (1), 11-18, (2017), ISSN: 2156-3381. Abstract | Links | BibTeX | Schlagwörter: Aluminum, Back-junction back-contact (BJBC) cells, boron, Conductivity, contact resistivity, Current density, Junctions, Photovoltaic cells, polysilicon, polysilicon on oxide (POLO) junctions, recombination, selective contacts, selectivity @article{Rienäcker2017b,
title = {Junction resistivity of carrier-selective polysilicon on oxide junctions and its impact on solar cell performance}, author = {M Rienäcker and M Bossmeyer and A Merkle and U Römer and F Haase and J Krügener and R Brendel and R Peibst}, doi = {10.1109/JPHOTOV.2016.2614123}, issn = {2156-3381}, year = {2017}, date = {2017-01-01}, journal = {IEEE Journal of Photovoltaics}, volume = {7}, number = {1}, pages = {11-18}, abstract = {We investigate the junction resistivity of high-quality carrier-selective polysilicon on oxide (POLO) junctions with the transfer length method. We demonstrate n+ POLO junctions with a saturation current density JC,poly of 6.2 fA/cm2 and a junction resistivity ρc of 0.6 mΩcm2, counterdoped n+ POLO junctions with 2.7 fA/cm2 and 1.3 mΩcm2, and p+ POLO junctions with 6.7 fA/cm2 and 0.2 mΩcm2. Such low junction resistivities and saturation current densities correspond to excellent selectivities S10 of up to 16.2. The efficiency potential for back-junction back-contact solar cells with these POLO junctions was determined to be larger than 25 % by numerical device simulations. We demonstrate experimentally a back-junction back-contact solar cell with p-type and n-type POLO junctions with an independently confirmed efficiency of 24.25 %.}, keywords = {Aluminum, Back-junction back-contact (BJBC) cells, boron, Conductivity, contact resistivity, Current density, Junctions, Photovoltaic cells, polysilicon, polysilicon on oxide (POLO) junctions, recombination, selective contacts, selectivity}, pubstate = {published}, tppubtype = {article} } We investigate the junction resistivity of high-quality carrier-selective polysilicon on oxide (POLO) junctions with the transfer length method. We demonstrate n+ POLO junctions with a saturation current density JC,poly of 6.2 fA/cm2 and a junction resistivity ρc of 0.6 mΩcm2, counterdoped n+ POLO junctions with 2.7 fA/cm2 and 1.3 mΩcm2, and p+ POLO junctions with 6.7 fA/cm2 and 0.2 mΩcm2. Such low junction resistivities and saturation current densities correspond to excellent selectivities S10 of up to 16.2. The efficiency potential for back-junction back-contact solar cells with these POLO junctions was determined to be larger than 25 % by numerical device simulations. We demonstrate experimentally a back-junction back-contact solar cell with p-type and n-type POLO junctions with an independently confirmed efficiency of 24.25 %.
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2016 |
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T. Dullweber, N. Wehmeier, A. Nowack, T. Brendemühl, S. Kajari-Schröder, and R. Brendel physica status solidi (a) 213 (11), 3046-3052, (2016). Abstract | Links | BibTeX | Schlagwörter: Aluminum, boron, boron silicate glass, emitters, silicon, Solar Cells @article{Dullweber2016c,
title = {Industrial bifacial n-type silicon solar cells applying a boron co-diffused rear emitter and an aluminum rear finger grid}, author = {T Dullweber and N Wehmeier and A Nowack and T Brendemühl and S Kajari-Schröder and R Brendel}, doi = {10.1002/pssa.201600346}, year = {2016}, date = {2016-11-01}, journal = {physica status solidi (a)}, volume = {213}, number = {11}, pages = {3046-3052}, abstract = {The solar industry is introducing p‐type monofacial passivated emitter and rear cells (PERC) into mass production. However, the efficiency of p‐type PERC cells is subject to light‐induced degradation (LID). In this paper, we introduce a novel solar cell design which we name BiCoRE as abbreviation of “bifacial co‐diffused rear emitter.” The BiCoRE cell process is very similar to the high volume proven PERC process sequence, but uses LID stable n‐type wafers. A boron silicate glass (BSG) silicon nitride (SiNz) stack at the rear side of the BiCoRE cells acts as protection layer against texturing and POCl3 diffusion, as boron dopant source during the POCl3 co‐diffusion as well as passivation layer. The rear contacts are formed by laser contact opening (LCO) and screen printing of an Al finger grid similar to the recently introduced PERC+ solar cells. The Al finger grid enables bifaciality and results in up to 8.5 μm deep aluminum back surface fields (Al‐BSFs) and up to 21.1% conversion efficiency obtained with n‐type reference solar cells. The multifunctional BSG/SiNz stack demonstrates up to 20.6% conversion efficiency with BiCoRE solar cells. When illuminated from the rear side, the BiCoRE cells exhibit conversion efficiencies up to 16.1% which corresponds to a bifaciality of 78%. }, keywords = {Aluminum, boron, boron silicate glass, emitters, silicon, Solar Cells}, pubstate = {published}, tppubtype = {article} } The solar industry is introducing p‐type monofacial passivated emitter and rear cells (PERC) into mass production. However, the efficiency of p‐type PERC cells is subject to light‐induced degradation (LID). In this paper, we introduce a novel solar cell design which we name BiCoRE as abbreviation of “bifacial co‐diffused rear emitter.” The BiCoRE cell process is very similar to the high volume proven PERC process sequence, but uses LID stable n‐type wafers. A boron silicate glass (BSG) silicon nitride (SiNz) stack at the rear side of the BiCoRE cells acts as protection layer against texturing and POCl3 diffusion, as boron dopant source during the POCl3 co‐diffusion as well as passivation layer. The rear contacts are formed by laser contact opening (LCO) and screen printing of an Al finger grid similar to the recently introduced PERC+ solar cells. The Al finger grid enables bifaciality and results in up to 8.5 μm deep aluminum back surface fields (Al‐BSFs) and up to 21.1% conversion efficiency obtained with n‐type reference solar cells. The multifunctional BSG/SiNz stack demonstrates up to 20.6% conversion efficiency with BiCoRE solar cells. When illuminated from the rear side, the BiCoRE cells exhibit conversion efficiencies up to 16.1% which corresponds to a bifaciality of 78%.
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C. Kranz, B. Wolpensinger, R. Brendel, and T. Dullweber Analysis of local aluminum rear contacts of bifacial PERC+ solar cells Artikel IEEE Journal of Photovoltaics 6 (4), 830, (2016). Abstract | Links | BibTeX | Schlagwörter: Aluminum, Analytical models, Bifacial passivated emitter rear contact (PERC) solar cells, contact formation, Photovoltaic cells, Printing, Scanning electron microscopy, screen-printing, silicon, Solids @article{Kranz2016b,
title = {Analysis of local aluminum rear contacts of bifacial PERC+ solar cells}, author = {C Kranz and B Wolpensinger and R Brendel and T Dullweber}, doi = {10.1109/JPHOTOV.2016.2551465}, year = {2016}, date = {2016-07-01}, journal = {IEEE Journal of Photovoltaics}, volume = {6}, number = {4}, pages = {830}, abstract = {A recently published industrial passivated emitter rear contact (PERC) solar cell concept called PERC+ enables bifacial applications by printing an aluminum (Al) finger grid instead of the full-area Al layer aligned to the laser contact openings on the rear side. We demonstrate that the rear contacts of these PERC+ solar cells exhibit back-surface field (BSF) depths of around 6 μm over a large range of contact linewidths, whereas PERC cells with full-area Al rear layer show a reduction of the Al-BSF depths for narrower contact lines. Using an existing analytical model for the local contact formation, we show that the measured Al-BSF depths are well described solely by the different volume of Al paste printed on the rear side. Consequently, the open-circuit voltage of PERC+ solar cells improves by up to 5 mV when reducing the contact linewidth only. In contrast, for PERC cells with full-area Al layer, the Voc slightly decreases with narrower contact linewidths due to the thinner Al-BSF depths. We observe a strongly reduced number of voids in the Al-Si eutectic layer for PERC+ cells, compared with PERC. As physical root cause for void formation, we propose the minimization of surface energy of the Al-Si melt.}, keywords = {Aluminum, Analytical models, Bifacial passivated emitter rear contact (PERC) solar cells, contact formation, Photovoltaic cells, Printing, Scanning electron microscopy, screen-printing, silicon, Solids}, pubstate = {published}, tppubtype = {article} } A recently published industrial passivated emitter rear contact (PERC) solar cell concept called PERC+ enables bifacial applications by printing an aluminum (Al) finger grid instead of the full-area Al layer aligned to the laser contact openings on the rear side. We demonstrate that the rear contacts of these PERC+ solar cells exhibit back-surface field (BSF) depths of around 6 μm over a large range of contact linewidths, whereas PERC cells with full-area Al rear layer show a reduction of the Al-BSF depths for narrower contact lines. Using an existing analytical model for the local contact formation, we show that the measured Al-BSF depths are well described solely by the different volume of Al paste printed on the rear side. Consequently, the open-circuit voltage of PERC+ solar cells improves by up to 5 mV when reducing the contact linewidth only. In contrast, for PERC cells with full-area Al layer, the Voc slightly decreases with narrower contact linewidths due to the thinner Al-BSF depths. We observe a strongly reduced number of voids in the Al-Si eutectic layer for PERC+ cells, compared with PERC. As physical root cause for void formation, we propose the minimization of surface energy of the Al-Si melt.
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2015 |
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H. Schulte-Huxel, S. Kajari-Schröder, and R. Brendel IEEE Journal of Photovoltaics 5 (6), 1606-1612, (2015). Links | BibTeX | Schlagwörter: Al metallization, Aluminum, cell interconnection, Finite element analysis, finite-element method (FEM) simulations, Glass, laser processing, metallization, module integration, Surface morphology, Surface treatment, Welding @article{Schulte-Huxel2015b,
title = {Analysis of thermal processes driving laser-welding of aluminum deposited on glass substrates for module interconnection of silicon solar cells}, author = {H Schulte-Huxel and S Kajari-Schröder and R Brendel}, doi = {10.1109/JPHOTOV.2015.2478027}, year = {2015}, date = {2015-11-01}, journal = {IEEE Journal of Photovoltaics}, volume = {5}, number = {6}, pages = {1606-1612}, keywords = {Al metallization, Aluminum, cell interconnection, Finite element analysis, finite-element method (FEM) simulations, Glass, laser processing, metallization, module integration, Surface morphology, Surface treatment, Welding}, pubstate = {published}, tppubtype = {article} } |
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H. Schulte-Huxel, S. Kajari-Schröder, and R. Brendel Thermal processes driving laser-welding for module interconnection Inproceedings IEEE (Hrsg.): 2015 IEEE 42nd Photovoltaic Specialist Conference (PVSC), New Orleans, LA, USA, (2015), ISBN: 978-1-4799-7944-8. Links | BibTeX | Schlagwörter: Al metallization, Aluminum, cell interconnection, FEM simulations, Laser beams, laser processing, Measurement by laser beam, module integration, reliability, Thickness measurement, Welding @inproceedings{Schulte-Huxel2015,
title = {Thermal processes driving laser-welding for module interconnection}, author = {H Schulte-Huxel and S Kajari-Schröder and R Brendel}, editor = {IEEE}, doi = {10.1109/PVSC.2015.7356432}, isbn = {978-1-4799-7944-8}, year = {2015}, date = {2015-06-14}, booktitle = {2015 IEEE 42nd Photovoltaic Specialist Conference (PVSC)}, journal = {Proceedings of the 42nd IEEE Photovoltaic Specialists Conference}, address = {New Orleans, LA, USA}, keywords = {Al metallization, Aluminum, cell interconnection, FEM simulations, Laser beams, laser processing, Measurement by laser beam, module integration, reliability, Thickness measurement, Welding}, pubstate = {published}, tppubtype = {inproceedings} } |
2014 |
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S. Jack, J. Parzefall, T. Luttmann, P. Janßen, and F. Giovannetti Flat Plate Aluminum Heat Pipe Collector with Inherently Limited Stagnation Temperature Artikel Energy Procedia 48 , 105-113, (2014), ISSN: 1876-6102, (Proceedings of the 2nd International Conference on Solar Heating and Cooling for Buildings and Industry (SHC 2013)). Links | BibTeX | Schlagwörter: Aluminum, copper substitution, Flat plate collector, heat pipe, stagnation @article{Jack2014b,
title = {Flat Plate Aluminum Heat Pipe Collector with Inherently Limited Stagnation Temperature}, author = {S Jack and J Parzefall and T Luttmann and P Janßen and F Giovannetti}, doi = {10.1016/j.egypro.2014.02.013}, issn = {1876-6102}, year = {2014}, date = {2014-04-01}, journal = {Energy Procedia}, volume = {48}, pages = {105-113}, note = {Proceedings of the 2nd International Conference on Solar Heating and Cooling for Buildings and Industry (SHC 2013)}, keywords = {Aluminum, copper substitution, Flat plate collector, heat pipe, stagnation}, pubstate = {published}, tppubtype = {article} } |
2013 |
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S. Eidelloth, F. Heinemeyer, D. Münster, and R. Brendel Aluminum Evaporation and Etching for the Front-Side Metallization of Solar Cells Artikel IEEE Journal of Photovoltaics 3 (2), 702-708, (2013). Links | BibTeX | Schlagwörter: Aluminum, Etching, metallization, Photovoltaic cells, Resists, Silver @article{Eidelloth2013,
title = {Aluminum Evaporation and Etching for the Front-Side Metallization of Solar Cells}, author = {S Eidelloth and F Heinemeyer and D Münster and R Brendel}, doi = {10.1109/JPHOTOV.2013.2239361}, year = {2013}, date = {2013-04-01}, journal = {IEEE Journal of Photovoltaics}, volume = {3}, number = {2}, pages = {702-708}, keywords = {Aluminum, Etching, metallization, Photovoltaic cells, Resists, Silver}, pubstate = {published}, tppubtype = {article} } |
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C. Mader, U. Eitner, S. Kajari-Schröder, and R. Brendel Bow of Silicon Wafers After In-Line High-Rate Evaporation of Aluminum Artikel IEEE Journal of Photovoltaics 3 (1), 212-216, (2013). Links | BibTeX | Schlagwörter: Aluminum, Elastoplastic deformation, In-line evaporation, Photovoltaic cells, Photovoltaic systems, silicon, Silicon solar cell, Strain, Stress, Temperature measurement, wafer bow @article{Mader2013,
title = {Bow of Silicon Wafers After In-Line High-Rate Evaporation of Aluminum}, author = {C Mader and U Eitner and S Kajari-Schröder and R Brendel}, doi = {10.1109/JPHOTOV.2012.2218578}, year = {2013}, date = {2013-01-01}, journal = {IEEE Journal of Photovoltaics}, volume = {3}, number = {1}, pages = {212-216}, keywords = {Aluminum, Elastoplastic deformation, In-line evaporation, Photovoltaic cells, Photovoltaic systems, silicon, Silicon solar cell, Strain, Stress, Temperature measurement, wafer bow}, pubstate = {published}, tppubtype = {article} } |
2011 |
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S. Gatz, T. Dullweber, and R. Brendel Contact resistance of local rear side contacts of screen-printed silicon PERC solar cells with efficiencies up to 19.4% Inproceedings IEEE (Hrsg.): 2011 37th IEEE Photovoltaic Specialists Conference, 003658, Seattle, WA, USA, (2011), ISSN: 0160-8371. Links | BibTeX | Schlagwörter: Aluminum, Contact resistance, Dielectrics, Photovoltaic cells, Resistance, solar energy @inproceedings{Gatz2011c,
title = {Contact resistance of local rear side contacts of screen-printed silicon PERC solar cells with efficiencies up to 19.4%}, author = {S Gatz and T Dullweber and R Brendel}, editor = {IEEE}, doi = {10.1109/PVSC.2011.6185943}, issn = {0160-8371}, year = {2011}, date = {2011-06-01}, booktitle = {2011 37th IEEE Photovoltaic Specialists Conference}, pages = {003658}, address = {Seattle, WA, USA}, keywords = {Aluminum, Contact resistance, Dielectrics, Photovoltaic cells, Resistance, solar energy}, pubstate = {published}, tppubtype = {inproceedings} } |
2010 |
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F. Werner, B. Veith, V. Tiba, P. Poodt, F. Roozeboom, R. Brendel, and J. Schmidt Applied Physics Letters 97 (16), 162103, (2010). Links | BibTeX | Schlagwörter: Aluminum, atomic layer deposition, carrier density, ozone, surface passivation @article{Werner2010,
title = {Very low surface recombination velocities on p- and n-type c-Si by ultrafast spatial atomic layer deposition of aluminum oxide}, author = {F Werner and B Veith and V Tiba and P Poodt and F Roozeboom and R Brendel and J Schmidt}, doi = {10.1063/1.3505311}, year = {2010}, date = {2010-10-01}, journal = {Applied Physics Letters}, volume = {97}, number = {16}, pages = {162103}, keywords = {Aluminum, atomic layer deposition, carrier density, ozone, surface passivation}, pubstate = {published}, tppubtype = {article} } |
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C. Mader, J. Müller, S. Gatz, T. Dullweber, and R. Brendel Rear-side point-contacts by inline thermal evaporation of aluminum Inproceedings IEEE (Hrsg.): 2010 35th IEEE Photovoltaic Specialists Conference, 001446-001449, Honolulu, HI, USA, (2010), ISSN: 0160-8371. Links | BibTeX | Schlagwörter: Aluminum, Electrical resistance measurement, Mathematical model, metallization, Photovoltaic cells, silicon, Surface treatment @inproceedings{Mader2010,
title = {Rear-side point-contacts by inline thermal evaporation of aluminum}, author = {C Mader and J Müller and S Gatz and T Dullweber and R Brendel}, editor = {IEEE}, doi = {10.1109/PVSC.2010.5614430}, issn = {0160-8371}, year = {2010}, date = {2010-06-01}, booktitle = {2010 35th IEEE Photovoltaic Specialists Conference}, pages = {001446-001449}, address = {Honolulu, HI, USA}, keywords = {Aluminum, Electrical resistance measurement, Mathematical model, metallization, Photovoltaic cells, silicon, Surface treatment}, pubstate = {published}, tppubtype = {inproceedings} } |
2008 |
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R. Bock, J. Schmidt, R. Brendel, H. Schuhmann, and M. Seibt Electron microscopy analysis of silicon islands and line structures formed on screen-printed Al-doped p+-surfaces Inproceedings IEEE (Hrsg.): 2008 33rd IEEE Photovoltaic Specialists Conference, 1-5, San Diego, CA, USA, (2008), ISSN: 0160-8371. Links | BibTeX | Schlagwörter: Aluminum, Crystallization, Dispersion, Electron microscopy, nanostructures, Photovoltaic cells, Scanning electron microscopy, silicon, Transmission electron microscopy @inproceedings{Bock2008d,
title = {Electron microscopy analysis of silicon islands and line structures formed on screen-printed Al-doped p+-surfaces}, author = {R Bock and J Schmidt and R Brendel and H Schuhmann and M Seibt}, editor = {IEEE}, doi = {10.1109/PVSC.2008.4922485}, issn = {0160-8371}, year = {2008}, date = {2008-05-01}, booktitle = {2008 33rd IEEE Photovoltaic Specialists Conference}, pages = {1-5}, address = {San Diego, CA, USA}, keywords = {Aluminum, Crystallization, Dispersion, Electron microscopy, nanostructures, Photovoltaic cells, Scanning electron microscopy, silicon, Transmission electron microscopy}, pubstate = {published}, tppubtype = {inproceedings} } |