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Epitaxial GaAs Lift-off from Si(111) Wafer via 2D-GaSe Buffer Layer
N. Kojima, Y.-C. Wang, Y. Ohshita, M. Yamaguchi
III-V Semiconductor, Buffer Layer, Epitaxy, Flexible Substrate, Thin Film Solar Cell
Perovskites and Other Non-Silicon Materials, MJs and Tandems
Subtopic: III-V and Related Compound Semiconductors
Event: 37th European Photovoltaic Solar Energy Conference and Exhibition
Session: 3CO.5.4
615 - 617
ISBN: 3-936338-73-6
Paper DOI: 10.4229/EUPVSEC20202020-3CO.5.4
0,00 EUR
Document(s): paper


In recent years, thin film III-V cells using epitaxial lift-off (ELO) technique and substrate re-use has attracted increasing attention as low-cost, high-efficiency, light-weight and flexible solar cells. In this paper, the rapid ELO technique using mechanical cleavage via 2D-layered metal selenide was applied to the epitaxial GaAs layer transfer from 2-inch Si(111) substrate. As 2D-layered metal selenide, double 2D-buffer layers of GaSe and In2Se3 were grown on Si(111) 4o off substrate by MBE. The epitaxial GaAs layer transfer from 2-inch Si(111) wafer onto thin flexible PMMA or polyimide sheet was succeeded by using the thermal stress by liquid nitrogen dipping. The processing time is only around 10 sec. However, a lot of wrinkles were formed during temperature recovery to room temperature in the ELO process. To get smooth ELO-GaAs layer surface, further improvement of the ELO process is necessary. This rapid ELO technique has great potential for the dramatically cost reduction of thin film flexible III-V solar cells than the usual selective etching technique by aqueous acid.