Investigation of Rear-Emitter GaAs_0.75P_0.25 Top Cells for Application to III–V/Si Tandem Photovoltaics

Journal Article · Thu Sep 19 00:00:00 EDT 2019 · IEEE Journal of Photovoltaics

DOI:https://doi.org/10.1109/jphotov.2019.2939069· OSTI ID:1728453

Lepkowski, Daniel L. ^[1]; Boyer, Jacob T. ^[2]; Chmielewski, Daniel J. ^[2]; Silvaggio, Amber C. ^[2]; Ringel, Steven A. ^[2]; Grassman, Tyler J. ^[2]

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1. The Ohio State Univ., Columbus, OH (United States); The Ohio State University
2. The Ohio State Univ., Columbus, OH (United States)

A rear-emitter (rear-junction) n-on-p+ device design was investigated for use in metamorphic monolithic III-V/Si tandem solar cells as an alternative to the traditional front-emitter (front-junction) n+-on-p design for potentially greater resistance to threading dislocation-induced performance degradation. A comparison of MOCVD-grown rearversus front-emitter 1.7-eV bandgap GaAs_0.75P_0.25 top cell isotypes demonstrated as 30-mV advantage in WOC for the rear-emitter design. Here, this reduction in WOC was determined to be nearly equally caused by a reduction in junction recombination current as well as reduced reverse saturation current from improved quasi-neutral region transport. These results suggest that the rear-emitter design may indeed be a promising pathway for application to metamorphic cells, including III-V/Si tandems, where achieving maximum voltage output is often hindered by elevated dislocation densities. However, further optimization of short-circuit current collection is needed to overcome suboptimal collection probability profiles that could limit the efficacy of such structures.

• Research Organization: The Ohio State Univ., Columbus, OH (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• Contributing Organization: NSF (GRFP) NASA (NSTRF)
• Grant/Contract Number: EE0007539
• OSTI ID: 1728453
• Journal Information: IEEE Journal of Photovoltaics, Journal Name: IEEE Journal of Photovoltaics Journal Issue: 6 Vol. 9; ISSN 2156-3381
• Publisher: IEEE
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
III–V semiconductor materials
photovoltaic (PV)
photovoltaic cells
semiconductor epitaxial layers