Fabrication and Modeling of High-Efficiency Front Junction N-Type Silicon Solar Cells With Tunnel Oxide Passivating Back Contact
Abstract
This paper reports on in-depth understanding, modeling, and fabrication of 23.8% efficient 4 cm2 n-type Float Zone (FZ) silicon cells with a selective boron emitter and photolithography contact on front and tunnel oxide passivating contact on the back. Tunnel oxide passivating contact composed of a very thin chemically grown silicon oxide (~15 Å) capped with plasma-enhanced chemical vapor deposition (PECVD) grown 20 nm n + poly Si gave excellent surface passivation and carrier selectivity with very low saturation current density (~5 fA/cm2). A high-quality boron selective emitter was formed using ion implantation and solid source diffusion to minimize metal recombination and emitter saturation current density. Process optimization resulted in a cell Voc of 712 mV, Jsc of 41.2 mA/cm2, and FF of 0.811. Here, a simple methodology is used to model these cells which replaces tunnel oxide passivating contact region by electron and hole recombination velocities extracted from measured saturation current density of tunnel oxide passivating contact region and analysis. Using this approach and two-dimensional device modeling gave an excellent match between the measured and simulated cell parameters and efficiency, supporting excellent passivation and carrier selectivity of these contacts. Extended simulations showed that 26% cell efficiency can be achieved withmore »
- Authors:
-
- Suniva Inc., Norcross, GA (United States); Georgia Institute of Technology, Atlanta, GA (United States)
- Georgia Institute of Technology, Atlanta, GA (United States)
- Fraunhofer Institute for Solar Energy Systems, Freiburg (Germany)
- Publication Date:
- Research Org.:
- Georgia Institute of Technology, Atlanta, GA (United States)
- Sponsoring Org.:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
- OSTI Identifier:
- 1893913
- Grant/Contract Number:
- EE0007554
- Resource Type:
- Accepted Manuscript
- Journal Name:
- IEEE Journal of Photovoltaics
- Additional Journal Information:
- Journal Volume: 7; Journal Issue: 5; Journal ID: ISSN 2156-3381
- Publisher:
- IEEE
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 14 SOLAR ENERGY; carrier selective contact; high efficiency n-type Si solar cell; selective B emitter; tunnel oxide passivated contact
Citation Formats
Rohatgi, Ajeet, Rounsaville, Brian, Ok, Young-Woo, Tam, Andrew M., Zimbardi, Francesco, Upadhyaya, Ajay D., Tao, Yuguo, Madani, Keeya, Richter, Armin, Benick, Jan, and Hermle, Martin. Fabrication and Modeling of High-Efficiency Front Junction N-Type Silicon Solar Cells With Tunnel Oxide Passivating Back Contact. United States: N. p., 2017.
Web. doi:10.1109/jphotov.2017.2715720.
Rohatgi, Ajeet, Rounsaville, Brian, Ok, Young-Woo, Tam, Andrew M., Zimbardi, Francesco, Upadhyaya, Ajay D., Tao, Yuguo, Madani, Keeya, Richter, Armin, Benick, Jan, & Hermle, Martin. Fabrication and Modeling of High-Efficiency Front Junction N-Type Silicon Solar Cells With Tunnel Oxide Passivating Back Contact. United States. https://doi.org/10.1109/jphotov.2017.2715720
Rohatgi, Ajeet, Rounsaville, Brian, Ok, Young-Woo, Tam, Andrew M., Zimbardi, Francesco, Upadhyaya, Ajay D., Tao, Yuguo, Madani, Keeya, Richter, Armin, Benick, Jan, and Hermle, Martin. Thu .
"Fabrication and Modeling of High-Efficiency Front Junction N-Type Silicon Solar Cells With Tunnel Oxide Passivating Back Contact". United States. https://doi.org/10.1109/jphotov.2017.2715720. https://www.osti.gov/servlets/purl/1893913.
@article{osti_1893913,
title = {Fabrication and Modeling of High-Efficiency Front Junction N-Type Silicon Solar Cells With Tunnel Oxide Passivating Back Contact},
author = {Rohatgi, Ajeet and Rounsaville, Brian and Ok, Young-Woo and Tam, Andrew M. and Zimbardi, Francesco and Upadhyaya, Ajay D. and Tao, Yuguo and Madani, Keeya and Richter, Armin and Benick, Jan and Hermle, Martin},
abstractNote = {This paper reports on in-depth understanding, modeling, and fabrication of 23.8% efficient 4 cm2 n-type Float Zone (FZ) silicon cells with a selective boron emitter and photolithography contact on front and tunnel oxide passivating contact on the back. Tunnel oxide passivating contact composed of a very thin chemically grown silicon oxide (~15 Å) capped with plasma-enhanced chemical vapor deposition (PECVD) grown 20 nm n + poly Si gave excellent surface passivation and carrier selectivity with very low saturation current density (~5 fA/cm2). A high-quality boron selective emitter was formed using ion implantation and solid source diffusion to minimize metal recombination and emitter saturation current density. Process optimization resulted in a cell Voc of 712 mV, Jsc of 41.2 mA/cm2, and FF of 0.811. Here, a simple methodology is used to model these cells which replaces tunnel oxide passivating contact region by electron and hole recombination velocities extracted from measured saturation current density of tunnel oxide passivating contact region and analysis. Using this approach and two-dimensional device modeling gave an excellent match between the measured and simulated cell parameters and efficiency, supporting excellent passivation and carrier selectivity of these contacts. Extended simulations showed that 26% cell efficiency can be achieved with this cell structure by further optimization of wafer quality, emitter profile, and contact design},
doi = {10.1109/jphotov.2017.2715720},
journal = {IEEE Journal of Photovoltaics},
number = 5,
volume = 7,
place = {United States},
year = {Thu Jul 06 00:00:00 EDT 2017},
month = {Thu Jul 06 00:00:00 EDT 2017}
}
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