20%-efficient epitaxial GaAsP/Si tandem solar cells

Shizhao Fan; Zhengshan J. Yu; Yukun Sun; William Weigand; Pankul Dhingra; Mijung Kim; Ryan D. Hool; Erik D. Ratta; Zachary C. Holman; Minjoo L. Lee

doi:10.1016/j.solmat.2019.110144

20%-efficient epitaxial GaAsP/Si tandem solar cells

Shizhao Fan, Zhengshan J. Yu, Yukun Sun, William Weigand, Pankul Dhingra, Mijung Kim, Ryan D. Hool, Erik D. Ratta, Zachary C. Holman, Minjoo L. Lee

Research output: Contribution to journal › Article › peer-review

Abstract

We present epitaxial 1.7 eV/1.1 eV GaAs_0.75P_0.25/Si tandem cells with an NREL-certified efficiency of 20.0%, enabled by a thermally stable tunnel junction interconnect along with a hydrogenated amorphous Si (a-Si:H) carrier-selective contact for the Si bottom cell. Building on these promising tandem results, we also demonstrate a 16.5%-efficient GaAs_0.75P_0.25 single-junction top cell on Si and a 7.78%-efficient GaAs_0.75P_0.25-filtered Si bottom cell (both NREL-certified) with improved short-circuit current densities. The quantum efficiency of the GaAs_0.75P_0.25 single-junction top cell on Si is boosted across the whole wavelength range due to the use of a higher growth temperature, indicating an improved minority-carrier diffusion length. The implementation of random pyramid texturing at the Si back surface enables improved quantum efficiency at wavelengths of 900–1200 nm, corresponding to an increase of 1.42 mA/cm² in short-circuit current density. The improved short-circuit current densities of the sub-cells together show a pathway to >23% efficiency in a two-terminal tandem configuration.

Original language	English (US)
Article number	110144
Journal	Solar Energy Materials and Solar Cells
Volume	202
DOIs	https://doi.org/10.1016/j.solmat.2019.110144
State	Published - Nov 2019

Keywords

Epitaxial III-V/Si integration
GaAsP
Light trapping
Metamorphic growth
Silicon heterojunction
Tandem
Tunnel junction

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Renewable Energy, Sustainability and the Environment
Surfaces, Coatings and Films

Online availability

10.1016/j.solmat.2019.110144

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@article{4c3ad76ca938440cac67b9b7650c2cb6,

title = "20%-efficient epitaxial GaAsP/Si tandem solar cells",

abstract = "We present epitaxial 1.7 eV/1.1 eV GaAs0.75P0.25/Si tandem cells with an NREL-certified efficiency of 20.0%, enabled by a thermally stable tunnel junction interconnect along with a hydrogenated amorphous Si (a-Si:H) carrier-selective contact for the Si bottom cell. Building on these promising tandem results, we also demonstrate a 16.5%-efficient GaAs0.75P0.25 single-junction top cell on Si and a 7.78%-efficient GaAs0.75P0.25-filtered Si bottom cell (both NREL-certified) with improved short-circuit current densities. The quantum efficiency of the GaAs0.75P0.25 single-junction top cell on Si is boosted across the whole wavelength range due to the use of a higher growth temperature, indicating an improved minority-carrier diffusion length. The implementation of random pyramid texturing at the Si back surface enables improved quantum efficiency at wavelengths of 900–1200 nm, corresponding to an increase of 1.42 mA/cm2 in short-circuit current density. The improved short-circuit current densities of the sub-cells together show a pathway to >23% efficiency in a two-terminal tandem configuration.",

keywords = "Epitaxial III-V/Si integration, GaAsP, Light trapping, Metamorphic growth, Silicon heterojunction, Tandem, Tunnel junction",

author = "Shizhao Fan and Yu, {Zhengshan J.} and Yukun Sun and William Weigand and Pankul Dhingra and Mijung Kim and Hool, {Ryan D.} and Ratta, {Erik D.} 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 Grants No. 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. was supported by a National Aeronautics and Space Administration ( NASA ) Space Technology Research Fellowship. The research was carried out in part at the Frederick Seitz Materials Research Laboratory Central Facilities, University of Illinois at Urbana-Champaign. Funding Information: The authors at the University of Illinois at Urbana-Champaign acknowledge support from the National Science Foundation under Grants No. 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. was supported by a National Aeronautics and Space Administration (NASA) Space Technology Research Fellowship. The research was carried out in part at the Frederick Seitz Materials Research Laboratory Central Facilities, University of Illinois at Urbana-Champaign. Publisher Copyright: {\textcopyright} 2019 Elsevier B.V.",

year = "2019",

month = nov,

doi = "10.1016/j.solmat.2019.110144",

language = "English (US)",

volume = "202",

journal = "Solar Energy Materials and Solar Cells",

issn = "0927-0248",

publisher = "Elsevier",

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TY - JOUR

T1 - 20%-efficient epitaxial GaAsP/Si tandem solar cells

AU - Fan, Shizhao

AU - Yu, Zhengshan J.

AU - Sun, Yukun

AU - Weigand, William

AU - Dhingra, Pankul

AU - Kim, Mijung

AU - Hool, Ryan D.

AU - Ratta, Erik D.

AU - Holman, Zachary C.

AU - Lee, Minjoo L.

N1 - Funding Information: The authors at the University of Illinois at Urbana-Champaign acknowledge support from the National Science Foundation under Grants No. 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. was supported by a National Aeronautics and Space Administration ( NASA ) Space Technology Research Fellowship. The research was carried out in part at the Frederick Seitz Materials Research Laboratory Central Facilities, University of Illinois at Urbana-Champaign. Funding Information: The authors at the University of Illinois at Urbana-Champaign acknowledge support from the National Science Foundation under Grants No. 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. was supported by a National Aeronautics and Space Administration (NASA) Space Technology Research Fellowship. The research was carried out in part at the Frederick Seitz Materials Research Laboratory Central Facilities, University of Illinois at Urbana-Champaign. Publisher Copyright: © 2019 Elsevier B.V.

PY - 2019/11

Y1 - 2019/11

N2 - We present epitaxial 1.7 eV/1.1 eV GaAs0.75P0.25/Si tandem cells with an NREL-certified efficiency of 20.0%, enabled by a thermally stable tunnel junction interconnect along with a hydrogenated amorphous Si (a-Si:H) carrier-selective contact for the Si bottom cell. Building on these promising tandem results, we also demonstrate a 16.5%-efficient GaAs0.75P0.25 single-junction top cell on Si and a 7.78%-efficient GaAs0.75P0.25-filtered Si bottom cell (both NREL-certified) with improved short-circuit current densities. The quantum efficiency of the GaAs0.75P0.25 single-junction top cell on Si is boosted across the whole wavelength range due to the use of a higher growth temperature, indicating an improved minority-carrier diffusion length. The implementation of random pyramid texturing at the Si back surface enables improved quantum efficiency at wavelengths of 900–1200 nm, corresponding to an increase of 1.42 mA/cm2 in short-circuit current density. The improved short-circuit current densities of the sub-cells together show a pathway to >23% efficiency in a two-terminal tandem configuration.

AB - We present epitaxial 1.7 eV/1.1 eV GaAs0.75P0.25/Si tandem cells with an NREL-certified efficiency of 20.0%, enabled by a thermally stable tunnel junction interconnect along with a hydrogenated amorphous Si (a-Si:H) carrier-selective contact for the Si bottom cell. Building on these promising tandem results, we also demonstrate a 16.5%-efficient GaAs0.75P0.25 single-junction top cell on Si and a 7.78%-efficient GaAs0.75P0.25-filtered Si bottom cell (both NREL-certified) with improved short-circuit current densities. The quantum efficiency of the GaAs0.75P0.25 single-junction top cell on Si is boosted across the whole wavelength range due to the use of a higher growth temperature, indicating an improved minority-carrier diffusion length. The implementation of random pyramid texturing at the Si back surface enables improved quantum efficiency at wavelengths of 900–1200 nm, corresponding to an increase of 1.42 mA/cm2 in short-circuit current density. The improved short-circuit current densities of the sub-cells together show a pathway to >23% efficiency in a two-terminal tandem configuration.

KW - Epitaxial III-V/Si integration

KW - GaAsP

KW - Light trapping

KW - Metamorphic growth

KW - Silicon heterojunction

KW - Tandem

KW - Tunnel junction

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U2 - 10.1016/j.solmat.2019.110144

DO - 10.1016/j.solmat.2019.110144

M3 - Article

AN - SCOPUS:85071419824

SN - 0927-0248

VL - 202

JO - Solar Energy Materials and Solar Cells

JF - Solar Energy Materials and Solar Cells

M1 - 110144

ER -

20%-efficient epitaxial GaAsP/Si tandem solar cells

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