Wafer Bonded III–V on Silicon Multi -Junction Cell with Efficiency beyond 31%

Silicon-based multi-junction solar cells are under the spotlight as it is foreseen to be the next step for highest efficiency terrestrial photovoltaic flat panels. Indeed, recently it was experimentally shown that adding III-V top cells on a silicon bottom cell allowed exceeding the intrinsic Si single junction efficiency limit of 29.4% set by Auger recombination. In this study we focus on monolithic III-V//Si multi-junction two-terminal devices, as this architecture is directly compatible with actual module standards. We use surface activated wafer bonding to join the III-V and Si cells. As a result of material quality and process improvement, we present here a 2-terminal, 4 cm
²
GaInP/AIGaAs//Si triple-junction solar cell reaching 31.3% under AM1.5g 1-sun conditions.