TY - JOUR
T1 - Study of the interface in a GaP/Si heterojunction solar cell
AU - Saive, Rebecca
AU - Emmer, Hal
AU - Chen, Christopher T.
AU - Zhang, Chaomin
AU - Honsberg, Christiana
AU - Atwater, Harry
N1 - Funding Information:
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. 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. (Corresponding author: Rebecca Saive.) R. Saive, H. Emmer, C. T. Chen, and H. Atwater are with the California Institute of Technology, Pasadena, CA 91125 USA (e-mail:,r.saive@utwente.nl; hal.emmer@gmail.com; christopherchen@lbl.gov; haa@caltech.edu).
Publisher Copyright:
© 2018 IEEE.
PY - 2018/11
Y1 - 2018/11
N2 - 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.
AB - 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.
KW - Band alignment
KW - Kelvin probe (KP) force microscopy
KW - X-ray photoelectron spectroscopy
KW - interface
KW - silicon heterojunction (SHJ) solar cells
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U2 - 10.1109/JPHOTOV.2018.2861724
DO - 10.1109/JPHOTOV.2018.2861724
M3 - Article
AN - SCOPUS:85052605738
SN - 2156-3381
VL - 8
SP - 1568
EP - 1576
JO - IEEE Journal of Photovoltaics
JF - IEEE Journal of Photovoltaics
IS - 6
M1 - 8434086
ER -