Improving photo-generated carrier escape in quantum well solar cells

A. Alemu; A. Freundlich

doi:10.1117/12.908305

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21 February 2012 Improving photo-generated carrier escape in quantum well solar cells

A. Alemu, A. Freundlich

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Proceedings Volume 8256, Physics, Simulation, and Photonic Engineering of Photovoltaic Devices; 82560B (2012) https://doi.org/10.1117/12.908305
Event: SPIE OPTO, 2012, San Francisco, California, United States

Abstract

Using material systems displaying a band offset only on the conduction (GaAs/(In)GaAsN) or valence (GaAs/GaAsSb(N)) band, we offer device designs that rely on intra-subband thermal transitions accompanied by resonant tunneling to adjacent wells, which greatly accelerates the carrier escape process. Typically, photo-excited carriers in the well regions need about several nanoseconds to make their way out of the well, but a proper design of energy states in successive quantum wells can reduce this escape time to few picoseconds, leading to reduced recombination and higher carrier collection. Using a solar cell modeling program based on the drift-diffusion framework, we show that quantum well solar cells displaying such thermo-tunneling carrier escape process can substantially surpass the efficiency limit of their bulk counterpart.

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A. Alemu and A. Freundlich "Improving photo-generated carrier escape in quantum well solar cells", Proc. SPIE 8256, Physics, Simulation, and Photonic Engineering of Photovoltaic Devices, 82560B (21 February 2012); https://doi.org/10.1117/12.908305

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