@article{b66cfcce8a984e68b9a4c8eabea77a4b,
title = "Current-Matched III–V/Si Epitaxial Tandem Solar Cells with 25.0% Efficiency",
abstract = "III–V/Si epitaxial tandems with a 1.7-eV GaAsP top cell promise stable power conversion efficiencies above the fundamental limit of Si single-junction cells. However, III–V/Si epitaxial tandems have suffered from limited minority carrier diffusion length in the top cell, leading to reduced short-circuit current densities (JSC) and efficiencies. While conventional wisdom dictates that dislocation density in III–V/Si tandems must be reduced to boost efficiency, here, we show that heterointerface design and growth sequence also play critical roles in reducing recombination losses. Our improved GaAsP cells make use of a wide-band gap AlGaAsP electron-blocking layer that forms a pristine interface with GaAsP, resulting in a 10%–20% (absolute) boost in quantum efficiency over previous work in the critical red wavelength range (600–725 nm), despite similar dislocation density. Combining the improved top cell carrier collection with Si backside texturing, we obtain 25.0% efficient GaAsP/Si tandem cells with a closely matched JSC of 18.8 mA/cm2. Tandem solar cells consisting of a GaAsP top cell grown on Si can potentially offer an ideal combination of stability and efficiency. However, GaAsP/Si tandem cells are typically hampered by crystalline defects. Improving the quality of interfaces surrounding the GaAsP cell enables Fan et al. to demonstrate a 25% efficient tandem device.",
keywords = "Epitaxial III-V/Si integration, GaAsP, current match, red response, tandem",
author = "Shizhao Fan and Yu, {Zhengshan J.} and Hool, {Ryan D.} and Pankul Dhingra and William Weigand and Mijung Kim and Ratta, {Erik D.} and Li, {Brian D.} and Yukun Sun and Holman, {Zachary C.} and Lee, {Minjoo L.}",
note = "Funding Information: The authors at the University of Illinois at Urbana-Champaign acknowledge support from the National Science Foundation under grant nos. 1736181 , 1719567 , and 1810265 , while the authors at Arizona State University acknowledge support from the National Science Foundation under grant no. 1509864 . R.D.H. and B.D.L were supported by National Aeronautics and Space Administration (NASA) Space Technology Research Fellowships under grant numbers 80NSSC18K1171 and 80NSSC19K1174 , respectively. The research was carried out in part at the Frederick Seitz Materials Research Laboratory Central Facilities, University of Illinois at Urbana-Champaign. The authors would like to acknowledge Dr. Julio Antonio Nieri Soares for calibration of the Newport Sol1A solar simulator (model no. 1: 94021A) and his assistance in general. Funding Information: The authors at the University of Illinois at Urbana-Champaign acknowledge support from the National Science Foundation under grant nos. 1736181, 1719567, and 1810265, while the authors at Arizona State University acknowledge support from the National Science Foundation under grant no. 1509864. R.D.H. and B.D.L were supported by National Aeronautics and Space Administration (NASA) Space Technology Research Fellowships under grant numbers 80NSSC18K1171 and 80NSSC19K1174, respectively. The research was carried out in part at the Frederick Seitz Materials Research Laboratory Central Facilities, University of Illinois at Urbana-Champaign. The authors would like to acknowledge Dr. Julio Antonio Nieri Soares for calibration of the Newport Sol1A solar simulator (model no. 1: 94021A) and his assistance in general. S.F. M.L.L. R.D.H. Z.C.H. and Z.J.Y. designed the experiments. S.F. and M.L.L. designed the MBE growth structures. S.F. and R.D.H. performed MBE growth with assistance from B.D.L. and Y.S. S.F. fabricated the top cells. For the tandem cells, S.F. textured and cleaned the III–V/Si wafers, Z.J.Y. and W.W. fabricated the a-Si back contact, and S.F. completed the tandem fabrication. S.F. designed and deposited the anti-reflection coatings. S.F. and M.K. performed the PL and TRPL measurements. S.F. and R.D.H. performed the X-ray diffraction measurements. R.D.H. performed the EBIC characterization. P.D. performed the TEM sample preparation and imaging. S.F. and E.D.R. performed the ellipsometry measurements. S.F. performed the solar cell measurements. S.F. and M.L.L. wrote the paper. S.F. M.L.L. Z.C.H. Z.J.Y. R.D.H. and P.D. discussed the results and revised the manuscript. M.L.L. and Z.C.H. supervised the overall efforts at the University of Illinois and at Arizona State University, respectively. The authors declare no competing interests. Publisher Copyright: {\textcopyright} 2020",
year = "2020",
month = sep,
day = "23",
doi = "10.1016/j.xcrp.2020.100208",
language = "English (US)",
volume = "1",
journal = "Cell Reports Physical Science",
issn = "2666-3864",
publisher = "Cell Press",
number = "9",
}