III–V-on-silicon solar cells reaching 33% photoconversion efficiency in two-terminal configuration

Romain Cariou (1, 2) , Jan Benick (2) , Frank Feldmann (2) , Oliver Höhn (2) , Hubert Hauser (2) , Paul Beutel (2) , Nasser Razek , Markus Wimplinger , Benedikt Bläsi (2) , David Lackner (2) , Martin Hermle , Gerald Siefer (2) , Stefan Glunz , Andreas Bett (2) , Frank Dimroth (2)

1 NUCLEART - ARC-Nucleart CEA Grenoble
2 Fraunhofer ISE - Fraunhofer Institute for Solar Energy Systems

Silicon dominates the photovoltaic industry but the conversion efficiency of silicon single-junction solar cells is intrinsically constrained to 29.4%, and practically limited to around 27%. It is possible to overcome this limit by combining silicon with high-bandgap materials, such as III–V semiconductors, in a multi-junction device. Significant challenges associated with this material combination have hindered the development of highly efficient III–V/Si solar cells. Here, we demonstrate a III–V/Si cell reaching similar performances to standard III–V/Ge triple-junction solar cells. This device is fabricated using wafer bonding to permanently join a GaInP/GaAs top cell with a silicon bottom cell. The key issues of III–V/Si interface recombination and silicon's weak absorption are addressed using poly-silicon/SiO$_x$ passivating contacts and a novel rear-side diffraction grating for the silicon bottom cell. With these combined features, we demonstrate a two-terminal GaInP/GaAs//Si solar cell reaching a 1-sun AM1.5G conversion efficiency of 33.3%.

Domaines: Sciences de l'ingénieur [physics]; Energie électrique

Romain Cariou, Jan Benick, Frank Feldmann, Oliver Höhn, Hubert Hauser, et al.. III–V-on-silicon solar cells reaching 33% photoconversion efficiency in two-terminal configuration. Nature Energy, 2018, 3 (4), pp.326 - 333. ⟨10.1038/s41560-018-0125-0⟩. ⟨cea-01882171⟩