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Proceedings Paper

Study of InGaAs/GaAs quantum dot saturation level for the design of concentrated multi-junction solar cells
Author(s): Olivier Thériault; Anthony J. SpringThorpe; Jeffrey F. Wheeldon; Christopher E. Valdivia; Alexandre Walker; Bruno J. Riel; Karin Hinzer
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Paper Abstract

InAs quantum dots in a GaAs matrix are studied. Those quantum dots are used in applications to enhance the overall efficiency of multi-junction solar cells beyond 40%. Photoluminescence measurements at 77 K using a 532 nm laser have been performed on an epitaxially grown structure of self-assembled InAs quantum dots in a GaAs matrix upon a Ge substrate, where three energy levels are determined at En=0=1.01 eV, En=1=1.07 eV and En=2=1.13 eV. Theoretical calculations of the energy levels determine the quantum dots to be 7 nm high and have a 37 nm base diameter, which is close to atomic force microscopy measurements performed on the samples. Intensity dependant photoluminescence measurements reveal the saturation of the first excited energy level at 5×106 W/m2. A general model for the saturation of the first quantum dot excited energy level is then developed. This saturation model is applied to the AM1.5D solar spectrum at 297 K to determine the concentration of solar energy needed to saturate the first excited energy level within a multi-junction solar cell. Saturation was determined to be at ~1.56×104 suns (where 1 sun = 1000 W/m2). Since current solar concentrations are between 500-1000 suns concentration, the saturation of such quantum dots will not occur.

Paper Details

Date Published: 22 September 2010
PDF: 10 pages
Proc. SPIE 7750, Photonics North 2010, 77502T (22 September 2010);
Show Author Affiliations
Olivier Thériault, Univ. of Ottawa (Canada)
Anthony J. SpringThorpe, National Research Council Canada (Canada)
Jeffrey F. Wheeldon, Univ. of Ottawa (Canada)
Christopher E. Valdivia, Univ. of Ottawa (Canada)
Alexandre Walker, Univ. of Ottawa (Canada)
Bruno J. Riel, Cyrium Technologies Inc. (Canada)
Karin Hinzer, Univ. of Ottawa (Canada)

Published in SPIE Proceedings Vol. 7750:
Photonics North 2010
Henry P. Schriemer; Rafael N. Kleiman, Editor(s)

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