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21 February 2012 Improving photo-generated carrier escape in quantum well solar cells
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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.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
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);

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