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Investigation of Defects Generated During the Epitaxial Lift-off Process in a Flexible GaAs Solar Cell
New Phys.: Sae Mulli 2019; 69: 806~812
Published online August 30, 2019;
© 2019 New Physics: Sae Mulli.

Mo Geun SO1, Sang Jo LEE1, Hyun Jun JO1, Jong Su KIM*1, Thuy Thi NGUYEN2, Yeongho KIM2, Sang Jun LEE2, Heedae KIM3

1Department of Physics, Yeungnam University, Gyeongsan 38541, Korea
2Korea Research Institute of Standards and Science, Daejeon 34113, Korea
3School of Physics, Northeast Normal University, Changchun 130024, China
Correspondence to:
Received December 12, 2018; Revised April 12, 2019; Accepted April 12, 2019.
cc This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
We have to investigate the optical and the electrical properties of flexible GaAs solar cells fabricated by using the epitaxial lift-off (ELO) process. Used the photoluminescence (PL) and J-V measurements. The as-grown GaAs solar cells were transferred onto Au/polyimide (ELO-layer/Au; ELA) and polydimethylsiloxane (PDMS) (ELO-layer/PDMS; ELP) flexible substrates. At 300~K, we observed PL emission bands caused by defects below the GaAs band edge transition energy (1.425~eV) for both the ELA and the ELP samples. The PL intensities for the ELA and the ELP samples, which were due to the defects in those samples, were higher than that for the as-grown sample. Moreover, the interference effect due to the internal multireflection (IMR) of PL light is lead that the PL peak by the defects is observed as the PL with several peaks. The PL intensity of the ELA sample was enhanced by the reflection effect at the GaAs/Au interface. In the J-V characteristics, the short-circuit current density and the efficiency of ELA sample were reduced by about 2.13~mA/cm$ ^{2}$ and 1.7\%, respectively, compared to the corresponding values for the GaAs-ref sample, because photo-generated carriers were trapped by the defect states generated during the ELO process.
PACS numbers: 78.66.Fd, 78.40.$-$q, 73.40.Lq, 73.50.Gr
Keywords: GaAs, Solar cell, Epitaxial lift-of, Defects

August 2019, 69 (8)
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