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Proceedings Paper

Photoluminescence investigation for InAs quantum dots capped by GaAs1-xSbx layer with different Sb-composition (Conference Presentation)
Author(s): Baolai Liang; Diana L. Huffaker; Yuriy I. Mazur; Morgan E. Ware; Gregory J. Salamo; Ying Wang; Qinglin Guo; Shufang Wang; Guangsheng Fu
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Paper Abstract

Recently, to sandwich InAs QDs with GaAs1-xSbx layers have attracted enormous attention. It is expected to achieve a transition from type-I to type-II band alignment at ~ x=12%. The type-II InAs/GaAs1-xSbx QDs are predicted to be one of the optimizing active region materials for achieving high efficient intermediate-band solar cells. We first investigate PL properties of InAs/GaAs1-xSbx QD structures of different Sb compositions (x=0, 0.15, and 0.25) in the GaAs1-xSbx capping layer. By capping the InAs QDs with GaAs0.85Sb0.15 and GaAs0.75Sb0.25 layer, we are able to gain type II QDs. These type II QDs exhibit a clear multi-peaks characteristic under increasing laser excitation intensity, which stems from different carriers recombination routes due to the combination of InAs QDs with GaAs1-xSbx capping layer. Time-resolved PL measurements further confirm our assignment for the mnulti-peaks in the PL spectra. We then study carrier coupling inside vertically aligned InAs/GaAs and InAs/GaAs1-xSbx QD pairs. The features of InAs/GaAs1-xSbx QD pairs are very different from the traditional InAs/GaAs QD-pairs. Again, clear multi-peaks characteristic are observed under stronng laser excitation intensity, which stems from different carriers recombination routes from the top InAs/GaAs1-xSbx QDs. Our investigations indicate that the optical behavior and carrier dynamics in type-II InAs/GaAs1-xSbx QDs and QD-pairs are much more complicated than the InAs/GaAs QDs counterparts. This study provide useful information for understanding the band structure and carrier dynamics of the InAs/GaAs1-xSbx QDs for high efficiency solar cell applications.

Paper Details

Date Published: 14 March 2018
Proc. SPIE 10543, Quantum Dots and Nanostructures: Growth, Characterization, and Modeling XV, 1054308 (14 March 2018); doi: 10.1117/12.2290756
Show Author Affiliations
Baolai Liang, California NanoSystems Institute (United States)
Diana L. Huffaker, California NanoSystems Institute (United States)
Yuriy I. Mazur, Univ. of Arkansas (United States)
Morgan E. Ware, Univ. of Arkansas (United States)
Gregory J. Salamo, Univ. of Arkansas (United States)
Ying Wang, Hebei Univ. (China)
Qinglin Guo, Hebei Univ. (China)
Shufang Wang, Hebei Univ. (China)
Guangsheng Fu, Hebei Univ. (China)

Published in SPIE Proceedings Vol. 10543:
Quantum Dots and Nanostructures: Growth, Characterization, and Modeling XV
Diana L. Huffaker; Holger Eisele, Editor(s)

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