Optoelectronic Analysis of Multijunction Wire Array Solar Cells

Daniel B. Turner-Evans, Christopher T. Chen, Hal Emmer, William E. McMahon, Harry A. Atwater

Research output: Contribution to journalArticlepeer-review

9 Scopus Citations


Wire arrays have demonstrated promising photovoltaic performance as single junction solar cells and are well suited to defect mitigation in heteroepitaxy. These attributes can combine in tandem wire array solar cells, potentially leading to high efficiencies. Here, we demonstrate initial growths of GaAs on Si0.9Ge0.1 structures and investigate III-V on Si 1-xGex device design with an analytical model and optoelectronic simulations. We consider Si0.1Ge0.9 wires coated with a GaAs0.9P0.1 shell in three different geometries: conformal, hemispherical, and spherical. The analytical model indicates that efficiencies approaching 34% are achievable with high quality materials. Full field electromagnetic simulations serve to elucidate the optical loss mechanisms and demonstrate light guiding into the wire core. Simulated current-voltage curves under solar illumination reveal the impact of a varying GaAs0.9P0.1 minority carrier lifetime. Finally, defective regions at the hetero-interface are shown to have a negligible effect on device performance if highly doped so as to serve as a back surface field. Overall, the growths and the model demonstrate the feasibility of the proposed geometries and can be used to guide tandem wire array solar cell designs.

Original languageAmerican English
Article number014501
Number of pages8
JournalJournal of Applied Physics
Issue number1
StatePublished - 7 Jul 2013

NREL Publication Number

  • NREL/JA-5200-60508


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