Space III-V Multijunction solar cells on Ge/Si virtual substrates

García Vara, Iván and Rey-Stolle Prado, Ignacio and Hinojosa Arner, Manuel and Lombardero Hernández, Iván and Cifuentes Baro, Luis and Algora del Valle, Carlos and Nguyen, Huy and Morgan, Aled and Johnson, Andrew (2019). Space III-V Multijunction solar cells on Ge/Si virtual substrates. In: "2019 European Space Power Conference (ESPC)", 30/09/2019 - 04/10/2019, Juan-les-Pins, France. pp. 1-6.


Title: Space III-V Multijunction solar cells on Ge/Si virtual substrates
  • García Vara, Iván
  • Rey-Stolle Prado, Ignacio
  • Hinojosa Arner, Manuel
  • Lombardero Hernández, Iván
  • Cifuentes Baro, Luis
  • Algora del Valle, Carlos
  • Nguyen, Huy
  • Morgan, Aled
  • Johnson, Andrew
Item Type: Presentation at Congress or Conference (Article)
Event Title: 2019 European Space Power Conference (ESPC)
Event Dates: 30/09/2019 - 04/10/2019
Event Location: Juan-les-Pins, France
Title of Book: 2019 European Space Power Conference (ESPC)
Date: 2019
Freetext Keywords: III-V multijunction solar cell; lightweight solar cell; virtual substrate; porous silicon
Faculty: E.T.S.I. Telecomunicación (UPM)
Department: Electrónica Física
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Virtual substrates based on thin Ge layers on Si substrates by direct deposition have recently achieved high quality. In this work, their application as low cost, removable substrates for the growth of high efficiency, lightweight and flexible multijunction solar cells for space applications is analyzed. Experimental Ge single-junction solar cells and GaInP/Ga(In)As/Ge triple-junction solar cells using the Ge/Si virtual substrate as an active bottom junction (being the Si inactive), are implemented using medium quality Ge/Si virtual substrates with a 5 μ m Ge layer thickness. A lower quality in the Ge material, as compared to standard substrates, but enough carrier collection efficiency for a standard triple-junction, are shown. The expected formation of cracks during growth, due to the large thermal expansion coefficient mismatch with the Si substrate, is confirmed, and is found to be a major limiting factor for the performance of the solar cells. Strategies such as thinning the Ge + III-V structure and minimizing the thermal cycling during growth are discussed. Using an embedded porous Si layer to serve as buffer for the strain is being investigated. This porous layer could also serve as sacrificial layer for high throughput mechanical epitaxial lift-off in the manufacturing of lightweight and flexible multijunction cells. These embedded porous Si layers need to be engineered for optimum performance and compatibility with the Ge and III-V deposition processes.

Funding Projects

Madrid Regional GovernmentS2018/EMT-4308MADRID-PV2UnspecifiedUnspecified
Universidad Politécnica de MadridRP190910B073UnspecifiedUnspecifiedUnspecified
Government of SpainRTI2018-094291-B-I00UnspecifiedUnspecifiedUnspecified

More information

Item ID: 65223
DC Identifier:
OAI Identifier:
DOI: 10.1109/ESPC.2019.8932026
Official URL:
Deposited by: Memoria Investigacion
Deposited on: 10 May 2021 13:06
Last Modified: 10 May 2021 13:06
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