M Rienäcker; M Bossmeyer; A Merkle; U Römer; F Haase; J Krügener; R Brendel; R Peibst
In: IEEE Journal of Photovoltaics, Bd. 7, Nr. 1, S. 11-18, 2017, ISSN: 2156-3381.
@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 = {},
pubstate = {published},
tppubtype = {article}
}
J Krügener; F Kiefer; R Peibst; H J Osten
Comparison of experimental emitter saturation current densities and simulated defect densities of boron-implanted emitters Proceedings Article
In: IEEE, (Hrsg.): Proceedings of the 21st International Conference on Ion Implantation Technology (IIT), Tainan, Taiwan, 2016, ISBN: 978-1-5090-2025-6.
@inproceedings{Krügener2016b,
title = {Comparison of experimental emitter saturation current densities and simulated defect densities of boron-implanted emitters},
author = {J Krügener and F Kiefer and R Peibst and H J Osten},
editor = {IEEE},
doi = {10.1109/IIT.2016.7882856},
isbn = {978-1-5090-2025-6},
year = {2016},
date = {2016-09-26},
booktitle = {Proceedings of the 21st International Conference on Ion Implantation Technology (IIT)},
journal = {Proceedings of the 21st International Conference on Ion Implantation Technology (IIT)},
address = {Tainan, Taiwan},
abstract = {Ion implantation of boron is a promising technique for the preparation of p-type emitters in n-type silicon solar cells. Here, experimental emitter saturation current densities are compared with simulated defect densities, namely boron interstitial clusters and dislocation loops. We report on experimental conditions, which allow separating the specific impact of both defect types on the resulting electrical properties after annealing at 1050°C and surface passivation. In that way, dislocation loops are identified to be the dominating defect species under the used implant and annealing conditions.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
O Breitenstein; F Frühauf; D Hinken; K Bothe
In: IEEE Journal of Photovoltaics, Bd. 6, Nr. 5, S. 1243-1254, 2016.
@article{Breitenstein2016,
title = {Effective diffusion length and bulk saturation current density imaging in solar cells by spectrally filtered luminescence imaging},
author = {O Breitenstein and F Frühauf and D Hinken and K Bothe},
doi = {10.1109/JPHOTOV.2016.2571621},
year = {2016},
date = {2016-09-01},
journal = {IEEE Journal of Photovoltaics},
volume = {6},
number = {5},
pages = {1243-1254},
abstract = {Most methods for interpreting electroluminescence (EL) or photoluminescence (PL) images of solar cells evaluate the local diode voltages but not the local luminescence intensity itself. One exception is the Fuyuki approximation, which assumes that the local value of the luminescence signal is proportional to the local effective diffusion length. This dependence has been derived for infinitely thick solar cells and neglects self-absorption of the luminescence photons. However, for real solar cells and imaging conditions, with increasing diffusion length, the luminescence signal approaches a limiting value; hence, the Fuyuki approximation no longer holds. In this paper, we compare EL and PL images of multicrystalline solar cells using different kinds of light filtering and find that gentle shortpass filtering is useful for avoiding optical artifacts. Based on earlier calculations, a physically founded formula for the dependence of the gently shortpass-filtered luminescence signal on the bulk diffusion length, for a given rear surface recombination velocity, is presented. Since this formula only barely allows us to calculate the diffusion length from the luminescence signal, a simplified approximate formula is proposed, and its accuracy is checked. This method is tested on EL and Voc PL images of solar cells. We find that for a typical industrial multicrystalline Albackside solar cell, the obtained effective diffusion length images correlate well with such images obtained by spectral LBIC image evaluation. In addition, the saturation current density images correlate well with such images obtained by dark lock-in thermography, which show a much lower spatial resolution. The main limitation of the proposed method is that it is basically approximate and needs some fitting parameters.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
F Kiefer; J Krügener; F Heinemeyer; H J Osten; R Brendel; R Peibst
In: IEEE Journal of Photovoltaics, Bd. 6, Nr. 5, S. 1175-1182, 2016.
@article{Kiefer2016,
title = {Structural investigation of printed Ag/Al contacts on silicon and numerical modeling of their contact recombination},
author = {F Kiefer and J Krügener and F Heinemeyer and H J Osten and R Brendel and R Peibst},
doi = {10.1109/JPHOTOV.2016.2591318},
year = {2016},
date = {2016-08-01},
journal = {IEEE Journal of Photovoltaics},
volume = {6},
number = {5},
pages = {1175-1182},
abstract = {Ag/Al pastes allow for a sufficiently low contact resistivity of less than 5 mΩ cm2 with boron-doped p+ emitters. A drawback of those pastes is an enlarged recombination at the silicon/metal interface below those contacts, compared with Ag pastes. For previous Ag/Al pastes from 2013, the observed recombination is even higher than theoretically expected for a fully metal-covered surface. Newly developed Ag/Al pastes allow for a significant reduction of the recombination below the contact, compared with a 2013 Ag/Al paste; for example, the J0e,m et of an 92Ω/sq. p+ emitter has decreased from 3420 down to 1014 fA/cm2 due to the newly developed paste. For an Rsheet of 137 Ω/sq, the J0e,met is 1399 fA/cm2. Structural investigations of those contacts reveal the microscopic appearance of the contacted region. There are contact spikes of metal grown into the silicon. Those spikes cover 1-1.2% of the entire printed finger area. With values for area fraction and depth of the spikes, we conduct simulations of J0e,m et. With these simulations, we are able to explain the enlarged recombination at the contact interface and describe the experimentally measured J0e,m et for both Ag/Al pastes described in this paper.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
B Lim; T Brendemühl; T Dullweber; R Brendel
In: IEEE Journal of Photovoltaics, Bd. 6, Nr. 2, S. 447-453, 2016.
@article{Lim2016,
title = {Loss analysis of n-type passivated emitter and rear totally diffused back-junction silicon solar cells with efficiencies up to 21.2%},
author = {B Lim and T Brendemühl and T Dullweber and R Brendel},
doi = {10.1109/JPHOTOV.2016.2520211},
year = {2016},
date = {2016-03-01},
journal = {IEEE Journal of Photovoltaics},
volume = {6},
number = {2},
pages = {447-453},
abstract = {In this work, we present screen-printed n-type passivated emitter rear totally diffused (n-PERT) back-junction (BJ) silicon solar cells with efficiencies up to 21.2% on total area of 239 cm2. The process sequence is based on that of p-type passivated emitter and rear cells (p-PERC), adding only a boron diffusion at the beginning. We reduce the recombination at the homogeneous phosphorus-doped front surface field by a wet-chemical etch-back of 10-20 nm and apply an advanced five-busbar layout on the front side to increase the energy conversion efficiency. We simulate the performance of the n-PERT BJ solar cell using the conductive boundary model and perform a synergistic efficiency gain analysis to identify the main limitations of our n-PERT BJ solar cells. We observe the biggest gain of 0.72% absolute after eliminating recombination at the P-doped front surface field and find that reducing recombination in general is most important for further improving our n-PERT BJ solar cells.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
S Schäfer; C Gemmel; S Kajari-Schröder; R Brendel
Light trapping and surface passivation of micron-scaled macroporous blind holes Artikel
In: IEEE Journal of Photovoltaics, Bd. 6, Nr. 2, S. 397-403, 2016.
@article{Schäfer2016,
title = {Light trapping and surface passivation of micron-scaled macroporous blind holes},
author = {S Schäfer and C Gemmel and S Kajari-Schröder and R Brendel},
doi = {10.1109/JPHOTOV.2015.2505179},
year = {2016},
date = {2016-03-01},
journal = {IEEE Journal of Photovoltaics},
volume = {6},
number = {2},
pages = {397-403},
abstract = {We fabricate a blind hole surface texture by anodic etching of macroporous Si. The blind holes, i.e., pores that do not penetrate the wafer completely, have an average diameter of 2.7 μm, a distance of 4 μm, and a depth of 9 μm. This texture is capable of reducing the AM1.5G photon flux-weighted front reflectance to 1.5% without depositing an antireflection coating. The μm-feature size makes it a less fragile alternative to common nm-sized black silicon structures. We passivate the blind holes by atomic layer deposited AlOx. The blind hole texture allows for a carrier lifetime of (2.2 ± 0.25) ms corresponding to an effective surface recombination velocity of (8 ± 1.5) cm/s with respect to the macroscopic front surface. A direct comparison of the optical performance and the surface passivation quality with a standard SiNx-coated random pyramid surface shows that blind holes allow for a relative efficiency gain of (3 ± 0.2)% when applied, e.g., in an otherwise perfect back-contacted solar cell.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
O Breitenstein; J Bauer; D Hinken; K Bothe
Towards more accurate imaging of the local saturation current density in solar cells by using alternative PL evaluation methods Proceedings Article
In: IEEE, (Hrsg.): 2015 IEEE 42nd Photovoltaic Specialist Conference (PVSC), New Orleans, LA, USA, 2015, ISBN: 978-1-4799-7944-8.
@inproceedings{Breitenstein2015,
title = {Towards more accurate imaging of the local saturation current density in solar cells by using alternative PL evaluation methods},
author = {O Breitenstein and J Bauer and D Hinken and K Bothe},
editor = {IEEE},
doi = {10.1109/PVSC.2015.7356029},
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 = {},
pubstate = {published},
tppubtype = {inproceedings}
}
F Kiefer; R Peibst; T Ohrdes; J Krügener; H J Osten; R Brendel
Emitter recombination current densities of boron emitters with silver/aluminum pastes Proceedings Article
In: IEEE, (Hrsg.): 2014 IEEE 40th Photovoltaic Specialist Conference (PVSC), S. 2808-2812, Denver, CO, USA, 2014, ISBN: 978-1-4799-4398-2.
@inproceedings{Kiefer2014,
title = {Emitter recombination current densities of boron emitters with silver/aluminum pastes},
author = {F Kiefer and R Peibst and T Ohrdes and J Krügener and H J Osten and R Brendel},
editor = {IEEE},
doi = {10.1109/PVSC.2014.6925514},
isbn = {978-1-4799-4398-2},
year = {2014},
date = {2014-06-08},
booktitle = {2014 IEEE 40th Photovoltaic Specialist Conference (PVSC)},
journal = {Proceedings of the 40th IEEE Photovoltaic Specialists Conference},
pages = {2808-2812},
address = {Denver, CO, USA},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
F Haase; S Kajari-Schröder; R Brendel
In: Journal of Applied Physics, Bd. 114, Nr. 19, S. 194505, 2013.
@article{Haase2013,
title = {High efficiency back-contact back-junction thin-film monocrystalline silicon solar cells from the porous silicon process},
author = {F Haase and S Kajari-Schröder and R Brendel},
doi = {10.1063/1.4832775},
year = {2013},
date = {2013-11-01},
journal = {Journal of Applied Physics},
volume = {114},
number = {19},
pages = {194505},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
J Schmidt; V Titova; D Zielke
Organic-silicon heterojunction solar cells: open-circuit voltage potential and stability Artikel
In: Applied Physics Letters, Bd. 103, Nr. 18, S. 183901, 2013.
@article{Schmidt2013b,
title = {Organic-silicon heterojunction solar cells: open-circuit voltage potential and stability},
author = {J Schmidt and V Titova and D Zielke},
doi = {10.1063/1.4827303},
year = {2013},
date = {2013-10-01},
journal = {Applied Physics Letters},
volume = {103},
number = {18},
pages = {183901},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
M Müller; P P Altermatt; K Schlegel; G Fischer
A Method for Imaging the Emitter Saturation Current With Lateral Resolution Artikel
In: IEEE Journal of Photovoltaics, Bd. 2, Nr. 4, S. 586-588, 2012, ISSN: 2156-3381.
@article{Müller2012e,
title = {A Method for Imaging the Emitter Saturation Current With Lateral Resolution},
author = {M Müller and P P Altermatt and K Schlegel and G Fischer},
doi = {10.1109/JPHOTOV.2012.2195552},
issn = {2156-3381},
year = {2012},
date = {2012-10-01},
journal = {IEEE Journal of Photovoltaics},
volume = {2},
number = {4},
pages = {586-588},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
J Müller; K Bothe; S Herlufsen; T Ohrdes; R Brendel
In: IEEE Journal of Photovoltaics, Bd. 2, Nr. 4, S. 473-478, 2012.
@article{Müller2012c,
title = {Reverse saturation current density imaging of highly doped regions in silicon employing photoluminescence measurements},
author = {J Müller and K Bothe and S Herlufsen and T Ohrdes and R Brendel},
doi = {10.1109/JPHOTOV.2012.2201916},
year = {2012},
date = {2012-10-01},
journal = {IEEE Journal of Photovoltaics},
volume = {2},
number = {4},
pages = {473-478},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
J Müller; S Gatz; K Bothe; R Brendel
Optimizing the geometry of local aluminum-alloyed contacts to fully screen-printed silicon solar cells Proceedings Article
In: IEEE, (Hrsg.): 2012 38th IEEE Photovoltaic Specialists Conference, S. 002223-002228, Austin, TX, USA, 2012, ISBN: 978-1-4673-0064-3.
@inproceedings{Müller2012,
title = {Optimizing the geometry of local aluminum-alloyed contacts to fully screen-printed silicon solar cells},
author = {J Müller and S Gatz and K Bothe and R Brendel},
editor = {IEEE},
doi = {10.1109/PVSC.2012.6318038},
isbn = {978-1-4673-0064-3},
year = {2012},
date = {2012-06-01},
booktitle = {2012 38th IEEE Photovoltaic Specialists Conference},
pages = {002223-002228},
address = {Austin, TX, USA},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
F Haase; S Eidelloth; R Horbelt; K Bothe; E G Rojas; R Brendel
Loss analysis of back-contact back-junction thin-film monocrystalline silicon solar cells Proceedings Article
In: IEEE, (Hrsg.): 2011 37th IEEE Photovoltaic Specialists Conference, S. 002874-002877, Seattle, WA, USA, 2011, ISSN: 0160-8371.
@inproceedings{Haase2011cb,
title = {Loss analysis of back-contact back-junction thin-film monocrystalline silicon solar cells},
author = {F Haase and S Eidelloth and R Horbelt and K Bothe and E G Rojas and R Brendel},
editor = {IEEE},
doi = {10.1109/PVSC.2011.6186546},
issn = {0160-8371},
year = {2011},
date = {2011-06-01},
booktitle = {2011 37th IEEE Photovoltaic Specialists Conference},
pages = {002874-002877},
address = {Seattle, WA, USA},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
J Müller; K Bothe; S Gatz; F Haase; C Mader; R Brendel
Recombination at laser-processed local base contacts by dynamic infrared lifetime mapping Artikel
In: Journal of Applied Physics, Bd. 108, Nr. 12, S. 124513, 2010.
@article{Müller2010,
title = {Recombination at laser-processed local base contacts by dynamic infrared lifetime mapping},
author = {J Müller and K Bothe and S Gatz and F Haase and C Mader and R Brendel},
doi = {10.1063/1.3517109},
year = {2010},
date = {2010-12-01},
journal = {Journal of Applied Physics},
volume = {108},
number = {12},
pages = {124513},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
R Bock; J Schmidt; S Mau; B Hoex; R Brendel
In: IEEE Transactions on Electron Devices, Bd. 57, Nr. 8, S. 1966-1971, 2010, ISSN: 0018-9383.
@article{Bock2010c,
title = {The ALU+ Concept: N-Type Silicon Solar Cells With Surface-Passivated Screen-Printed Aluminum-Alloyed Rear Emitter},
author = {R Bock and J Schmidt and S Mau and B Hoex and R Brendel},
doi = {10.1109/TED.2010.2050953},
issn = {0018-9383},
year = {2010},
date = {2010-08-01},
journal = {IEEE Transactions on Electron Devices},
volume = {57},
number = {8},
pages = {1966-1971},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
R Bock; J Schmidt; S Mau; B Hoex; E Kessels; R Brendel
The ALU+ concept: N-type silicon solar cells with surface-passivated screen-printed aluminum-alloyed rear emitter Proceedings Article
In: IEEE, (Hrsg.): 2009 34th IEEE Photovoltaic Specialists Conference (PVSC), S. 000030-000035, Philadelphia, PA, USA, 2009, ISSN: 0160-8371.
@inproceedings{Bock2009b,
title = {The ALU+ concept: N-type silicon solar cells with surface-passivated screen-printed aluminum-alloyed rear emitter},
author = {R Bock and J Schmidt and S Mau and B Hoex and E Kessels and R Brendel},
editor = {IEEE},
doi = {10.1109/PVSC.2009.5411768},
issn = {0160-8371},
year = {2009},
date = {2009-06-01},
booktitle = {2009 34th IEEE Photovoltaic Specialists Conference (PVSC)},
pages = {000030-000035},
address = {Philadelphia, PA, USA},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
R Brendel; S Dreissigacker; N -P Harder; P P Altermatt
Theory of analyzing free energy losses in solar cells Artikel
In: Applied Physics Letters, Bd. 93, Nr. 17, S. 173503, 2008.
@article{Brendel2008,
title = {Theory of analyzing free energy losses in solar cells},
author = {R Brendel and S Dreissigacker and N -P Harder and P P Altermatt},
doi = {10.1063/1.3006053},
year = {2008},
date = {2008-10-01},
journal = {Applied Physics Letters},
volume = {93},
number = {17},
pages = {173503},
keywords = {},
pubstate = {published},
tppubtype = {article}
}