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Abstract
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| The use of thin GaAsSb capping layers (CLs) is demonstrated to provide InAs/GaAs quantum dot (QD) solar cells (SCs) with improved efficiencies up to 20%. The application of such CLs allows the tunability of the QD ground state, switching the QD-CL band alignment to type II for high Sb contents and extending the photoresponse up to 1.5 ?m. Moreover, the CL provides a significant contribution to the photocurrent. An improved carrier collection efficiency is also found to be a main reason behind the increase of the short-circuit current density, unveiling a negative impact of the wetting layer (WL) on carrier transport in standard InAs/GaAs QD SCs. Calculations from an 8×8 k·p method suggest the attribution of such an improvement to longer carrier lifetimes in the WL-CL structure due to the transition to a type-II band alignment in Sb-containing structures. A faster open-circuit voltage recovery under light concentration is demonstrated for high Sb content type-II QD-CL structures, leading, in turn, to faster efficiency improvements with light power. | |
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International
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JCR
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Title
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Proceedings of the 32nd European Pho-tovoltaic Solar Energy Conference and Exhibition |
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ISBN
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2196-100X |
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Impact factor JCR
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Impact info
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Volume
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Journal number
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From page
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32 |
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To page
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35 |
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Month
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SIN MES |
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