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Study of the Interface in a GaP/Si Heterojunction Solar Cell

Saive, Rebecca and Emmer, Hal and Chen, Christopher T. and Zhang, Chaomin and Honsberg, Christiana and Atwater, Harry (2018) Study of the Interface in a GaP/Si Heterojunction Solar Cell. IEEE Journal of Photovoltaics, 8 (6). pp. 1568-1576. ISSN 2156-3381. doi:10.1109/jphotov.2018.2861724.

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We have investigated the GaP/Si heterojunction interface for application in silicon heterojunction solar cells. We performed X-ray photoelectron spectroscopy (XPS) on thin layers of GaP grown on Si by metal organic chemical vapor deposition and molecular beam epitaxy. The conduction band offset was determined to be 0.9 ± 0.2 eV, which is significantly higher than predicted by Anderson's rule (0.3 eV). XPS also revealed the presence of Ga–Si bonds at the interface that are likely to be the cause of the observed interface dipole. Via cross-sectional Kelvin probe force microscopy (x-KPFM), we observed a charge transport barrier at the Si/GaP interface which is consistent with the high-conduction band offset determined by XPS and explains the low open-circuit voltage and low fill factor observed in GaP/Si heterojunction solar cells.

Item Type:Article
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URLURL TypeDescription
Saive, Rebecca0000-0001-7420-9155
Chen, Christopher T.0000-0001-5848-961X
Atwater, Harry0000-0001-9435-0201
Additional Information:© 2018 IEEE. IEEE Open Access. Manuscript received May 15, 2018; revised June 27, 2018; accepted July 25, 2018. Date of publication August 13, 2018; date of current version October 26, 2018. The authors would like to thank the Molecular Foundry for generously hosting the MOCVD growth and the Caltech MMRC for providing the XPS analytic tools and also L. Ding, S. Aloni, A. Nielander, N. Plymale, A. Shing, and L. Korte for helpful advice with measurements and data interpretation. This work was supported in part by the U.S. Department of Energy, Energy Efficiency and Renewable Energy Program, under Award No. DE-EE0006335 for band offset characterization and in part by the U.S Department of Energy and the National Science Foundation under grant EEC1041895 for other electrical and structural measurements and in part by the Molecular Foundry funded by the Office of Science, Office of Basic Energy Sciences, U.S. Department of Energy under Contract DE-AC02-05CH11231.
Funding AgencyGrant Number
Department of Energy (DOE)DE-EE0006335
Department of Energy (DOE)DE-AC02-05CH11231
Subject Keywords:Band alignment, interface, Kelvin probe (KP) force microscopy, silicon heterojunction (SHJ) solar cells, X-ray photoelectron spectroscopy
Issue or Number:6
Record Number:CaltechAUTHORS:20181115-113350220
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Official Citation:R. Saive, H. Emmer, C. T. Chen, C. Zhang, C. Honsberg and H. Atwater, "Study of the Interface in a GaP/Si Heterojunction Solar Cell," in IEEE Journal of Photovoltaics, vol. 8, no. 6, pp. 1568-1576, Nov. 2018. doi: 10.1109/JPHOTOV.2018.2861724
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:90919
Deposited By: George Porter
Deposited On:15 Nov 2018 20:56
Last Modified:16 Nov 2021 03:36

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