GaInP/GaAs/GaInAs Monolithic Tandem Cells for High-Performance Solar Concentrators

    Research output: Contribution to conferencePaper


    We present a new approach for ultra-high-performance tandem solar cells that involves inverted epitaxial growth and ultra-thin device processing. The additional degree of freedom afforded by the inverted design allows the monolithic integration of high-, and medium-bandgap, lattice-matched (LM) subcell materials with lower-bandgap, lattice-mismatched (LMM) materials in a tandem structure throughthe use of transparent compositionally graded layers. The current work concerns an inverted, series-connected, triple-bandgap, GaInP (LM, 1.87 eV)/GaAs (LM, 1.42 eV)/GaInAs (LMM,~1 eV) device structure grown on a GaAs substrate. Ultra-thin tandem devices are fabricated by mounting the epiwafers to pre-metallized Si wafer handles and selectively removing the parent GaAs substrate. The resultinghandle-mounted, ultra-thin tandem cells have a number of important advantages, including improved performance and potential reclamation/reuse of the parent substrate for epitaxial growth. Additionally, realistic performance modeling calculations suggest that terrestrial concentrator efficiencies in the range of 40-45% are possible with this new tandem cell approach. A laboratory-scale (0.24cm2), prototype GaInP/GaAs/GaInAs tandem cell with a terrestrial concentrator efficiency of 37.9% at a low concentration ratio (10.1 suns) is described, which surpasses the previous world efficiency record of 37.3%.
    Original languageAmerican English
    Number of pages4
    StatePublished - 2005
    EventInternational Conference on Solar Concentrators for the Generation of Electricity or Hydrogen - Scottsdale, Arizona
    Duration: 1 May 20055 May 2005


    ConferenceInternational Conference on Solar Concentrators for the Generation of Electricity or Hydrogen
    CityScottsdale, Arizona

    NREL Publication Number

    • NREL/CP-520-38646


    • concentrator tandem solar cells
    • photovoltaics (PV)
    • PV


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