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Integration of InGaP/GaAs/Ge triple‐junction solar cells on deeply patterned silicon substrates
Author(s) -
Scaccabarozzi Andrea,
Binetti Simona,
Acciarri Maurizio,
Isella Giovanni,
Campesato Roberta,
Gori Gabriele,
Casale Maria Cristina,
Mancarella Fulvio,
Noack Michael,
Känel Hans,
Miglio Leo
Publication year - 2016
Publication title -
progress in photovoltaics: research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.286
H-Index - 131
eISSN - 1099-159X
pISSN - 1062-7995
DOI - 10.1002/pip.2798
Subject(s) - materials science , chemical vapor deposition , optoelectronics , substrate (aquarium) , silicon , planar , layer (electronics) , germanium , photovoltaic system , solar cell , dislocation , nanotechnology , computer science , composite material , electrical engineering , oceanography , computer graphics (images) , engineering , geology
We report preliminary results on InGaP/InGaAs/Ge photovoltaic cells for concentrated terrestrial applications, monolithically integrated on engineered Si(001) substrates. Cells deposited on planar Ge/Si(001) epilayers, grown by plasma‐enhanced chemical vapor deposition, provide good efficiency and spectral response, despite the small thickness of the Ge epilayers and a threading dislocation density as large as 10 7 /cm 2 . The presence of microcracks generated by the thermal misfit is compensated by a dense collection grid that avoids insulated areas. In order to avoid the excessive shadowing introduced by the use of a dense grid, the crack density needs to be lowered. Here, we show that deep patterning of the Si substrate in blocks can be an option, provided that a continuous Ge layer is formed at the top, and it is suitably planarized before the metalorganic chemical vapor deposition. The crack density is effectively decreased, despite that the efficiency is also lowered with respect to unpatterned devices. The reasons of this efficiency reduction are discussed, and a strategy for improvement is proposed and explored. Full morphological analysis of the coalesced Ge blocks is reported, and the final devices are tested under concentrated AM1.5D spectrum. Copyright © 2016 John Wiley & Sons, Ltd.