Issue |
EPJ Photovolt.
Volume 12, 2021
EU PVSEC 2021: State of the Art and Developments in Photovoltaics
|
|
---|---|---|
Article Number | 6 | |
Number of page(s) | 6 | |
DOI | https://doi.org/10.1051/epjpv/2021007 | |
Published online | 09 November 2021 |
https://doi.org/10.1051/epjpv/2021007
Regular Article
Rear side dielectrics on interdigitating p+-(i)-n+ back-contact solar cells − hydrogenation vs. charge effects
1
Institute for Solar Energy Research Hamelin (ISFH), Am Ohrberg 1, 31860 Emmerthal, Germany
2
Institute of Electronic Materials and Devices, Leibniz Universität Hannover, Schneiderberg 32, 30167, Germany
3
Laboratory of Nano and Quantum Engineering, Leibniz Universität Hannover, Schneiderberg 39, 30167, Germany
4
Institute for Solid State Physics, Leibniz Universität Hannover, Appelstraße 2, 30167, Germany
* e-mail: rienaecker@isfh.de
Received:
1
July
2021
Received in final form:
21
September
2021
Accepted:
22
October
2021
Published online: 9 November 2021
Polysilicon-on-oxide (POLO) passivating contacts and interdigitated back-contact (IBC) cell technologies have recently attracted a lot of interest as candidates for the implementation in the next generation of solar cells. An IBC cell with POLO junctions for both polarities − a POLO2-IBC cell − has to electrically isolate the highly defective p+ and n+ poly-Si regions on the rear side of the cell to avoid parasitic recombination. Inserting an initially undoped, intrinsic (i) region between the p+ and n+ poly-Si regions was demonstrated to successfully prevent the parasitic recombination in the transition region of ISFH's 26.1%-efficient POLO2-IBC cell. In order to further improve the conversion efficiency towards 27%, we apply hydrogen-donating dielectric layer stacks to the p+-(i)-n+ POLO interdigitating rear side to enhance the passivation quality of the POLO junctions. We indeed show a significant improvement of POLO junctions on symmetrical full-area homogenously doped reference samples, but when we apply a hydrogen-donating layer stack on the p+-(i)-n+ POLO interdigitating rear side, we observe a strong degradation in the performance of the POLO2-IBC cell. We attribute this to the formation of a conductive channel between the p+ and n+ poly-Si regions due to the strong negative charge density of the hydrogen-donating layer stack.
Key words: POLO / IBC / hydrogenation / charge / recombination / passivating contact / polysilicon
© M. Rienäcker et al., Published by EDP Sciences, 2021
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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