Optimization of Poly-Si/SiOx Passivated Contacts for Crystalline Silicon Bottom Cells Applications

Julci Ditsougou; Thibaut Desrues; Anne Kaminski; Sébastien Dubois

doi:10.52825/siliconpv.v2i.1310

Authors

Julci Ditsougou CEA LITEN https://orcid.org/0009-0003-3798-3354
Thibaut Desrues CEA LITEN
Anne Kaminski Grenoble Institute of Technology
Sébastien Dubois CEA LITEN https://orcid.org/0000-0002-3003-2981

DOI:

https://doi.org/10.52825/siliconpv.v2i.1310

Keywords:

TOPcon, Passivated Contact, Hydrogenation, Solar Cell, Bottom-Cell, 2T Tandem, Variable Illumination

Abstract

In this study we investigate the coupled impacts of poly-Si thickness, dopant activation annealing temperature and hydrogenation on n-TOPCon and p-TOPCon passivated contacts. Their performance is first assessed by Photoconductance Decay (PCD) measurements on symmetrical and asymmetrical cell precursors before being evaluated on cells by I-V characterizations. We show that high-temperature annealing of poly-Si layers is responsible for excessive dopants penetration in the substrate, which can then be limited by the presence of a thicker poly-Si layer. Moreover, these thicker poly-Si layers benefit more from hydrogenation steps, enabling i-V_oc of around 720 mV and carrier lifetimes of up to 5 ms on cell precursors. Finally, while increasing the thickness leads to current limitation under AM1.5G (1 Sun) illumination, this limitation is less pronounced under IR illumination. We therefore demonstrate that for tandem applications, the bottom-cell can benefit from a gain in V_oc and FF without suffering from a major optical limitation.

Downloads

Download data is not yet available.

References

[1] M. Boccard et C. Ballif, « Influence of the Subcell Properties on the Fill Factor of Two-Terminal Perovskite–Silicon Tandem Solar Cells », ACS Energy Lett., vol. 5, no 4, p. 1077‑1082, avr. 2020, doi: 10.1021/acsenergylett.0c00156.

[2] W. Chi, S. K. Banerjee, K. G. D. I. Jayawardena, S. R. P. Silva, et S. I. Seok, « Perov-skite/Silicon Tandem Solar Cells: Choice of Bottom Devices and Recombination Lay-ers », ACS Energy Lett., vol. 8, no 3, p. 1535‑1550, mars 2023, doi: 10.1021/acsenergylett.2c02725.

[3] S. W. Glunz et al., « Silicon‐based passivating contacts: The TOPCon route », Progress in Photovoltaics, vol. 31, no 4, p. 341‑359, avr. 2023, doi: 10.1002/pip.3522.

[4] F.-J. Haug et al., « Passivating Polysilicon Recombination Junctions for Crystalline Sili-con Solar Cells », Physica Rapid Research Ltrs, vol. 15, no 9, p. 2100272, sept. 2021, doi: 10.1002/pssr.202100272.

[5] B. Marteau, T. Desrues, Q. Rafhay, A. Kaminski, et S. Dubois, « Passivating Silicon Tunnel Diode for Perovskite on Silicon Nip Tandem Solar Cells », Energies, vol. 16, no 11, p. 4346, mai 2023, doi: 10.3390/en16114346.

[6] C. Oliveau, T. Desrues, A. Lanterne, C. Seron, S. Rousseau, et S. Dubois, « Double-Side Integration of High Temperature Passivated Contacts: Application to Cast-Mono Si », in 2020 47th IEEE Photovoltaic Specialists Conference (PVSC), Calgary, AB, Canada: IEEE, juin 2020, p. 1163‑1166. doi: 10.1109/PVSC45281.2020.9300752.

[7] T. Desrues et al., « Poly-Si/SiO x Passivating Contacts on Both Sides: A Versatile Tech-nology For High Efficiency Solar Cells », in 2021 IEEE 48th Photovoltaic Specialists Conference (PVSC), Fort Lauderdale, FL, USA: IEEE, juin 2021, p. 1069‑1072. doi: 10.1109/PVSC43889.2021.9518773.

[8] B. W. H. van de Loo et al., « On the hydrogenation of Poly-Si passivating contacts by Al2O3 and SiN thin films », Solar Energy Materials and Solar Cells, vol. 215, p. 110592, sept. 2020, doi: 10.1016/j.solmat.2020.110592.

[9] Z. Rui et al., « On the passivation mechanism of poly-silicon and thin silicon oxide on crystal silicon wafers », Solar Energy, vol. 194, p. 18‑26, déc. 2019, doi: 10.1016/j.solener.2019.10.064.

[10] Yuguo Tao et al., « 730 mV implied Voc enabled by tunnel oxide passivated contact with PECVD grown and crystallized n+ polycrystalline Si », in 2015 IEEE 42nd Photovoltaic Specialist Conference (PVSC), New Orleans, LA: IEEE, juin 2015, p. 1‑5. doi: 10.1109/PVSC.2015.7356218.

[11] J. Linke et al., « Poly-Si thickness and temperature dependent oxide disruption induced by penetration of the interfacial oxide in (p) poly-Si/SiOx passivating contacts », Solar Energy Materials and Solar Cells, vol. 246, p. 111890, oct. 2022, doi: 10.1016/j.solmat.2022.111890.

[12] G. Bunea, K. Wilson, Y. Meydbray, M. Campbell, et D. De Ceuster, « Low Light Perfor-mance of Mono-Crystalline Silicon Solar Cells », in 2006 IEEE 4th World Conference on Photovoltaic Energy Conference, Waikoloa, HI: IEEE, 2006, p. 1312‑1314. doi: 10.1109/WCPEC.2006.279655.