CC BY 4.0Schygulla, PatrickPatrickSchygullaMüller, RalphRalphMüllerHöhn, OliverOliverHöhnSchachtner, MichaelMichaelSchachtnerChojniak, DavidDavidChojniakCordaro, AndreaAndreaCordaroTabernig, StefanStefanTabernigBläsi, BenediktBenediktBläsiPolman, AlbertAlbertPolmanSiefer, GeraldGeraldSieferLackner, DavidDavidLacknerDimroth, FrankFrankDimroth2024-03-252024-03-252025Note-ID: 00008A7Ehttps://publica.fraunhofer.de/handle/publica/464477https://doi.org/10.24406/h-46447710.1002/pip.376910.24406/h-4644772-s2.0-85181692800In this work, we present the fabrication and analysis of a wafer-bonded GaInP/GaInAsP//Si triple-junction solar cell with 36.1% conversion efficiency under AM1.5g spectral illumination. The new cell design presents an improvement over previous III-V//Si triple-junction cells by the implementation of a rear-heterojunction for the middle cell. Furthermore, an advanced metallodielectric rear-side grating was used for light trapping enhancement in the silicon bottom cell that increased the silicon subcell current by 1.4 mA/cm2. The external radiative efficiency was quantified to be 1.5 times higher compared to a reference device with a GaInAsP homojunction middle cell. A luminescent coupling factor of 0.46 between the middle and bottom subcell was determined. The share of recombination in the space-charge region was experimentally shown to be insignificant as intended by the rear-heterojunction design. Overall, the open-circuit voltage of the middle cell increased by 61 mV compared to the previous generation. Given the established long-term stability of III-V and silicon-based solar cells, these results are promising steps towards the future employment of III-V/Si tandem solar cells.enback-side reflectorexternal radiative efficiencyGaInAsPIII-V//Si multi-junction solar cellsluminescence couplingMOVPErear-heterojunctionsilicon-based tandem solar cellsefficiency improvementRadiative efficiencyjournal article