Radiation Hardness of Ultra-thin GaAs Solar Cells with Rear-side Silver Mirror
Romain Cariou1, Hung-Ling Chen2, Andrea Cattoni2, Karim Medjoubi1, Jérémie Lefèvre 3, Bruno BOIZOT 3, Oliver Höhn4, David Lackner4, Frank Dimroth4, Stéphane Collin2
1Univ Grenoble Alpes, CEA, LITEN, DTS, LMPI, INES, F-38000 Grenoble, France
/2Centre for Nanoscience and Nanotechnology (C2N), CNRS, University Paris-Sud / Paris-Saclay, 91120 Palaiseau, France
/3Laboratoire des Solides Irradiés, CNRS-UMR 7642, CEA-DRF-IRAMIS, Ecole Polytechnique, Université Paris-Saclay, 91120 Palaiseau, France
/4Fraunhofer Institute for Solar Energy Systems - ISE, 79110 Freiburg, Germany

For space solar cells, thinner is better: indeed reducing the absorber thickness enables mass savings and radiation hardness improvements. However if the solar cells absorber thickness is simply reduced, the end-of-life (EOL) performance advantage of ultra-thin cells compared to bulk counterpart will only happen at very high fluences. By combining thinner absorber with efficient light trapping structures, ultra-thin solar cells can have superior EOL performances (efficiency, W/kg, W/m2) at moderate fluences. Recent advances have shown that ~ 200nm thin GaAs cells with a nanostructured back mirror can reach ~ 20% BOL efficiency. In this study, we review the potential of such ultra-thin GaAs cell technology for space applications. The first experimental results of 1 MeV electron irradiation tests on ultra-thin GaAs solar cells with Ag back mirror will be presented, and the radiation hardness will be compared with bulk GaAs solar cells.