Design Window for SHJ Cells: Joint Impact of Base Thickness and Doping Under AM1.5G

Jacques Joachim Faye; Aly Toure; Mamadou Lamine Samb; Dimity Diassy

doi:doi:10.11648/j.ajee.20251304.11

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| Peer-Reviewed

Design Window for SHJ Cells: Joint Impact of Base Thickness and Doping Under AM1.5G

Jacques Joachim Faye

, Aly Toure

, Mamadou Lamine Samb^*

, Dimity Diassy

Published in American Journal of Energy Engineering (Volume 13, Issue 4)

Received: 9 October 2025 Accepted: 17 October 2025 Published: 31 October 2025

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Abstract

We numerically map the joint impact of base thickness (e) and donor density (N_D) on silicon heterojunction (SHJ) cells under AM1.5G using SILVACO ATLAS (drift–diffusion with SRH/Auger and field/concentration dependent mobilities). Optics is treated by 2D specular ray tracing (no texturing), so results constitute a conservative baseline at small e. To isolate e and N_D, the a Si:H/c Si interface is held fixed across parameter sweeps. We identify an absorption–collection trade off: J_sc increases from thin to moderate e and then saturates or declines; V_oc decreases with increasing e and high N_D due to enhanced recombination. The fill factor peaks at small e under low to moderate N_D. Efficiency exhibits a robust optimum at moderate thickness (e.g., e ≈ 120-160μm) and intermediate N_D, whereas heavy doping shifts the optimum but ultimately degrades V_oc/FF via Auger (and, in extended models, band gap narrowing). From a design standpoint, we delineate a practical window that balances resistivity and recombination while avoiding heavy doping. Limitations: absence of light trapping and fixed interface, mean our absolute metrics are conservative, but trends and optima are robust. Planned extensions include Lambertian/textured optics, interface sweeps, and calibrated BGN/contact models to raise absolute values without altering the identified trade offs.

Published in	American Journal of Energy Engineering (Volume 13, Issue 4)
DOI	10.11648/j.ajee.20251304.11
Page(s)	158-170
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2025. Published by Science Publishing Group

Keywords

SHJ/HIT Solar Cell, Silicon, TCAD, Thickness, Doping, J_sc, V_oc, Fill Factor, Efficiency

References

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APA Style

Faye, J. J., Toure, A., Samb, M. L., Diassy, D. (2025). Design Window for SHJ Cells: Joint Impact of Base Thickness and Doping Under AM1.5G. American Journal of Energy Engineering, 13(4), 158-170. https://doi.org/10.11648/j.ajee.20251304.11

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ACS Style

Faye, J. J.; Toure, A.; Samb, M. L.; Diassy, D. Design Window for SHJ Cells: Joint Impact of Base Thickness and Doping Under AM1.5G. Am. J. Energy Eng. 2025, 13(4), 158-170. doi: 10.11648/j.ajee.20251304.11

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AMA Style

Faye JJ, Toure A, Samb ML, Diassy D. Design Window for SHJ Cells: Joint Impact of Base Thickness and Doping Under AM1.5G. Am J Energy Eng. 2025;13(4):158-170. doi: 10.11648/j.ajee.20251304.11

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@article{10.11648/j.ajee.20251304.11,
  author = {Jacques Joachim Faye and Aly Toure and Mamadou Lamine Samb and Dimity Diassy},
  title = {Design Window for SHJ Cells: Joint Impact of Base Thickness and Doping Under AM1.5G
},
  journal = {American Journal of Energy Engineering},
  volume = {13},
  number = {4},
  pages = {158-170},
  doi = {10.11648/j.ajee.20251304.11},
  url = {https://doi.org/10.11648/j.ajee.20251304.11},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajee.20251304.11},
  abstract = {We numerically map the joint impact of base thickness (e) and donor density (ND) on silicon heterojunction (SHJ) cells under AM1.5G using SILVACO ATLAS (drift–diffusion with SRH/Auger and field/concentration dependent mobilities). Optics is treated by 2D specular ray tracing (no texturing), so results constitute a conservative baseline at small e. To isolate e and ND, the a Si:H/c Si interface is held fixed across parameter sweeps. We identify an absorption–collection trade off: Jsc increases from thin to moderate e and then saturates or declines; Voc decreases with increasing e and high ND due to enhanced recombination. The fill factor peaks at small e under low to moderate ND. Efficiency exhibits a robust optimum at moderate thickness (e.g., e ≈ 120-160μm) and intermediate ND, whereas heavy doping shifts the optimum but ultimately degrades Voc/FF via Auger (and, in extended models, band gap narrowing). From a design standpoint, we delineate a practical window that balances resistivity and recombination while avoiding heavy doping. Limitations: absence of light trapping and fixed interface, mean our absolute metrics are conservative, but trends and optima are robust. Planned extensions include Lambertian/textured optics, interface sweeps, and calibrated BGN/contact models to raise absolute values without altering the identified trade offs.
},
 year = {2025}
}

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TY  - JOUR
T1  - Design Window for SHJ Cells: Joint Impact of Base Thickness and Doping Under AM1.5G

AU  - Jacques Joachim Faye
AU  - Aly Toure
AU  - Mamadou Lamine Samb
AU  - Dimity Diassy
Y1  - 2025/10/31
PY  - 2025
N1  - https://doi.org/10.11648/j.ajee.20251304.11
DO  - 10.11648/j.ajee.20251304.11
T2  - American Journal of Energy Engineering
JF  - American Journal of Energy Engineering
JO  - American Journal of Energy Engineering
SP  - 158
EP  - 170
PB  - Science Publishing Group
SN  - 2329-163X
UR  - https://doi.org/10.11648/j.ajee.20251304.11
AB  - We numerically map the joint impact of base thickness (e) and donor density (ND) on silicon heterojunction (SHJ) cells under AM1.5G using SILVACO ATLAS (drift–diffusion with SRH/Auger and field/concentration dependent mobilities). Optics is treated by 2D specular ray tracing (no texturing), so results constitute a conservative baseline at small e. To isolate e and ND, the a Si:H/c Si interface is held fixed across parameter sweeps. We identify an absorption–collection trade off: Jsc increases from thin to moderate e and then saturates or declines; Voc decreases with increasing e and high ND due to enhanced recombination. The fill factor peaks at small e under low to moderate ND. Efficiency exhibits a robust optimum at moderate thickness (e.g., e ≈ 120-160μm) and intermediate ND, whereas heavy doping shifts the optimum but ultimately degrades Voc/FF via Auger (and, in extended models, band gap narrowing). From a design standpoint, we delineate a practical window that balances resistivity and recombination while avoiding heavy doping. Limitations: absence of light trapping and fixed interface, mean our absolute metrics are conservative, but trends and optima are robust. Planned extensions include Lambertian/textured optics, interface sweeps, and calibrated BGN/contact models to raise absolute values without altering the identified trade offs.

VL  - 13
IS  - 4
ER  -

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Author Information

Jacques Joachim Faye

Department of Physics and Chemistry, University Iba Der Thiam of Thies, Thies, Senegal

Contact Email

http://orcid.org/0009-0009-0033-5066
Aly Toure

Department of Physics and Chemistry, University Iba Der Thiam of Thies, Thies, Senegal

Contact Email

http://orcid.org/0009-0009-9736-7733
Mamadou Lamine Samb

Department of Physics and Chemistry, University Iba Der Thiam of Thies, Thies, Senegal

Contact Email

http://orcid.org/0000-0003-0695-553X
Dimity Diassy

Department of Physics and Chemistry, University Iba Der Thiam of Thies, Thies, Senegal

Contact Email

http://orcid.org/0009-0000-8064-4583

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APA Style

Faye, J. J., Toure, A., Samb, M. L., Diassy, D. (2025). Design Window for SHJ Cells: Joint Impact of Base Thickness and Doping Under AM1.5G. American Journal of Energy Engineering, 13(4), 158-170. https://doi.org/10.11648/j.ajee.20251304.11

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ACS Style

Faye, J. J.; Toure, A.; Samb, M. L.; Diassy, D. Design Window for SHJ Cells: Joint Impact of Base Thickness and Doping Under AM1.5G. Am. J. Energy Eng. 2025, 13(4), 158-170. doi: 10.11648/j.ajee.20251304.11

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AMA Style

Faye JJ, Toure A, Samb ML, Diassy D. Design Window for SHJ Cells: Joint Impact of Base Thickness and Doping Under AM1.5G. Am J Energy Eng. 2025;13(4):158-170. doi: 10.11648/j.ajee.20251304.11

Copy | Download

@article{10.11648/j.ajee.20251304.11,
  author = {Jacques Joachim Faye and Aly Toure and Mamadou Lamine Samb and Dimity Diassy},
  title = {Design Window for SHJ Cells: Joint Impact of Base Thickness and Doping Under AM1.5G
},
  journal = {American Journal of Energy Engineering},
  volume = {13},
  number = {4},
  pages = {158-170},
  doi = {10.11648/j.ajee.20251304.11},
  url = {https://doi.org/10.11648/j.ajee.20251304.11},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajee.20251304.11},
  abstract = {We numerically map the joint impact of base thickness (e) and donor density (ND) on silicon heterojunction (SHJ) cells under AM1.5G using SILVACO ATLAS (drift–diffusion with SRH/Auger and field/concentration dependent mobilities). Optics is treated by 2D specular ray tracing (no texturing), so results constitute a conservative baseline at small e. To isolate e and ND, the a Si:H/c Si interface is held fixed across parameter sweeps. We identify an absorption–collection trade off: Jsc increases from thin to moderate e and then saturates or declines; Voc decreases with increasing e and high ND due to enhanced recombination. The fill factor peaks at small e under low to moderate ND. Efficiency exhibits a robust optimum at moderate thickness (e.g., e ≈ 120-160μm) and intermediate ND, whereas heavy doping shifts the optimum but ultimately degrades Voc/FF via Auger (and, in extended models, band gap narrowing). From a design standpoint, we delineate a practical window that balances resistivity and recombination while avoiding heavy doping. Limitations: absence of light trapping and fixed interface, mean our absolute metrics are conservative, but trends and optima are robust. Planned extensions include Lambertian/textured optics, interface sweeps, and calibrated BGN/contact models to raise absolute values without altering the identified trade offs.
},
 year = {2025}
}

Copy | Download

TY  - JOUR
T1  - Design Window for SHJ Cells: Joint Impact of Base Thickness and Doping Under AM1.5G

AU  - Jacques Joachim Faye
AU  - Aly Toure
AU  - Mamadou Lamine Samb
AU  - Dimity Diassy
Y1  - 2025/10/31
PY  - 2025
N1  - https://doi.org/10.11648/j.ajee.20251304.11
DO  - 10.11648/j.ajee.20251304.11
T2  - American Journal of Energy Engineering
JF  - American Journal of Energy Engineering
JO  - American Journal of Energy Engineering
SP  - 158
EP  - 170
PB  - Science Publishing Group
SN  - 2329-163X
UR  - https://doi.org/10.11648/j.ajee.20251304.11
AB  - We numerically map the joint impact of base thickness (e) and donor density (ND) on silicon heterojunction (SHJ) cells under AM1.5G using SILVACO ATLAS (drift–diffusion with SRH/Auger and field/concentration dependent mobilities). Optics is treated by 2D specular ray tracing (no texturing), so results constitute a conservative baseline at small e. To isolate e and ND, the a Si:H/c Si interface is held fixed across parameter sweeps. We identify an absorption–collection trade off: Jsc increases from thin to moderate e and then saturates or declines; Voc decreases with increasing e and high ND due to enhanced recombination. The fill factor peaks at small e under low to moderate ND. Efficiency exhibits a robust optimum at moderate thickness (e.g., e ≈ 120-160μm) and intermediate ND, whereas heavy doping shifts the optimum but ultimately degrades Voc/FF via Auger (and, in extended models, band gap narrowing). From a design standpoint, we delineate a practical window that balances resistivity and recombination while avoiding heavy doping. Limitations: absence of light trapping and fixed interface, mean our absolute metrics are conservative, but trends and optima are robust. Planned extensions include Lambertian/textured optics, interface sweeps, and calibrated BGN/contact models to raise absolute values without altering the identified trade offs.

VL  - 13
IS  - 4
ER  -

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