Degradation of Ge Subcells by Thermal Load During the Growth of Multijunction Solar Cells

Barrigón Montañés, Enrique and Ochoa Gómez, Mario and García Vara, Iván and Barrutia Poncela, Laura and Algora del Valle, Carlos and Rey-Stolle Prado, Ignacio (2017). Degradation of Ge Subcells by Thermal Load During the Growth of Multijunction Solar Cells. "Progress in Photovoltaics: Research and Applications", v. n/a (n. n/a); pp. 1-10. ISSN 1099-159X. https://doi.org/10.1002/pip.2948.

Description

Title: Degradation of Ge Subcells by Thermal Load During the Growth of Multijunction Solar Cells
Author/s:
  • Barrigón Montañés, Enrique
  • Ochoa Gómez, Mario
  • García Vara, Iván
  • Barrutia Poncela, Laura
  • Algora del Valle, Carlos
  • Rey-Stolle Prado, Ignacio
Item Type: Article
Título de Revista/Publicación: Progress in Photovoltaics: Research and Applications
Date: October 2017
ISSN: 1099-159X
Volume: n/a
Subjects:
Freetext Keywords: Ge solar cells, multijunction solar cells, thermal degradation, thermal load
Faculty: Instituto de Energía Solar (IES) (UPM)
Department: Electrónica Física
UPM's Research Group: Semiconductores III-V
Creative Commons Licenses: None

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Abstract

Germanium solar cells are used as bottom subcells in many multijunction solar cell designs. The question remains whether the thermal load originated by the growth of the upper layers of the multijunction solar cell structure affects the Ge subcell performance. Here, we report and analyze the performance degradation of the Ge subcell due to such thermal load in lattice-matched GaInP/Ga(In)As/Ge triple-junction solar cells. Specifically, we have detected a quantum efficiency loss in the wavelength region corresponding to the emitter layer (which accounts for up to 20% loss in equivalent JSC) and up to 55 mV loss in VOC of the Ge subcell as compared with analogous devices grown as single-junction Ge solar cells on the same type of substrates. We prove experimentally that there is no direct correlation between the loss in VOC and the doping level of the base. Our simulations show that both the JSC and VOC losses are consistent with a degradation of the minority carrier properties at the emitter, in particular at the initial nanometers of the emitter next to the emitter/window heterointerface. In addition, we also rule out the gradual emitter profile shape as the origin of the degradation observed. Our findings underscore the potential to obtain higher efficiencies in Ge-based multijunction solar cells if strategies to mitigate the impact of the thermal load are taken into consideration.

Funding Projects

TypeCodeAcronymLeaderTitle
Horizon 2020656208NEXTNANOCELLSLUNDS UNIVERSITETNext generation nanowire solar cells
FP7607153LONGESSTIQE plcLow Cost Germanium Substrates for Next Generation 4-Junction Space Solar Cells Utilising Dilute Nitride Technology
Government of SpainTEC2014-54260-C3-1-PENARCarlos AlgoraEvaluación de arquitecturas de nueva generación en células solares multiunión para lograr eficiencias del 50%
Government of SpainTEC2015-66722-RTAILLÓNIgnacio Rey-Stolle PradoCélulas tándem III-V/Si: hacia una tecnología fotovoltaica de panel plano con células multiunión
Madrid Regional GovernmentS2013/MAE-2780MADRID-PVUnspecifiedMateriales, dispositivos y tecnología para el desarrollo de la industria fotovoltaica

More information

Item ID: 48239
DC Identifier: http://oa.upm.es/48239/
OAI Identifier: oai:oa.upm.es:48239
DOI: 10.1002/pip.2948
Official URL: https://doi.org/10.1002/pip.2948
Deposited by: Dr Ignacio Rey-Stolle
Deposited on: 24 Oct 2017 07:50
Last Modified: 01 Dec 2018 23:30
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