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Monolithic two-terminal III-V//Si triple-junction solar cells with 30.2% efficiency under 1-Sun AM1.5g

 
: Cariou, R.; Benick, J.; Beutel, P.; Razek, N.; Flötgen, C.; Hermle, M.; Lackner, D.; Glunz, S.W.; Bett, A.W.; Wimplinger, M.; Dimroth, F.

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Volltext (PDF; )

IEEE Journal of Photovoltaics 7 (2017), Nr.1, S.367-373
ISSN: 2156-3381
ISSN: 2156-3403
Englisch
Zeitschriftenaufsatz, Elektronische Publikation
Fraunhofer ISE ()
Materialien - Solarzellen und Technologie; Photovoltaik; Silicium-Photovoltaik; III-V und Konzentrator-Photovoltaik; Epitaxie; Si-Folien und SiC-Abscheidungen; silicon; wafer bonding; triple junction solar cells

Abstract
Stacking III-V p-n junctions on top of wafer-based silicon solar cells is a promising way to go beyond the silicon single-junction efficiency limit. In this study, triple-junction GaInP/AlxGa1-xAs//Si solar cells were fabricated using surface-activated direct wafer bonding. Metal-organic-vapor-phase-epitaxy-grown GaInP/AlxGa1-xAs top cells are bonded at low temperature to independently prepared wafer-based silicon cells. n-Si//n-GaAs interfaces were investigated and achieved bulk-like bond strength, high transparency, and conductivity homogeneously over 4-inch wafer area. We used transfer-matrix optical modeling to identify the best design options to reach current-matched two-terminal devices with different mid-cell bandgaps (1.42, 1.47, and 1.52 eV). Solar cells were fabricated accordingly and calibrated under AM1.5g 1-sun conditions. An improved Si back-side passivation process is presented, leading to a current density of 12.4 mA/cm2 (AM1.5g), measured for a flat Si cell below GaAs. The best 4 cm2 GaInP/GaAs//Si triple-junction cell reaches 30.2% 1-sun efficiency.

: http://publica.fraunhofer.de/dokumente/N-435579.html