Descripción
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Dilute nitride GaAsSbN is an ideal candidate to form the 1-1.15 eV lattice-matched sub-cell that would significantly enhance the performance of 3- and 4-junction solar cells. However, growth problems inherent to this quaternary alloy lead typically to a poor crystal quality that limits its applicability. Better compositional control and crystal quality have been recently reported by growing the material as a GaAsSb/GaAsN superlattice, because of the spatial separation of Sb and N that avoid miscibility problems. Moreover, these structures provide bandgap tunability trough period thickness. Here we study the performance of lattice-matched 1.15 eV GaAsSb/GaAsN type-II perlattice p-i-n junction solar cells with different period thickness and compare them with the bulk and GaAsSbN/GaAs type-I superlattice counterparts. We demonstrate carrier lifetime tunability through the period thickness in the type-II structures. However, the long carrier lifetimes achievable with periods thicker than 12 nm are incompatible with a high carrier extraction efficiency under short-circuit conditions. Only superlattices with thinner periods and short carrier lifetimes show good solar cell performance. Quantum kinetic calculations based on the non-equilibrium Green?s function (NEGF) formalism predict a change in transport regime from direct tunneling extraction to sequential tunneling with sizable thermionic emission components when passing from 6 nm to 12 nm period length, which for low carrier lifetime results in a decrease of extraction efficiency by more than 30%. | |
Internacional
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Si |
Nombre congreso
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SPIE OPTO 2018 |
Tipo de participación
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960 |
Lugar del congreso
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San Franciso, EE.UU. |
Revisores
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Si |
ISBN o ISSN
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9781510615397 |
DOI
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10.1117/12.2290079 |
Fecha inicio congreso
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27/01/2018 |
Fecha fin congreso
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01/02/2018 |
Desde la página
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1052701 |
Hasta la página
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1052709 |
Título de las actas
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Proceedings Vol 10527 Physics, Simulation, and Photonic Engineering of Photovoltaic Devices VII |