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Proceedings Paper

Optical characteristics of InAlAs/GaAlAs/GaAs quantum dots (Conference Presentation)
Author(s): Baolai Liang; Diana L. Huffaker; Yuriy I. Mazur; Morgan Ware; Gregory J. Salamo; Linlin Su; Ying Wang; Qinglin Guo

Paper Abstract

The type-I to type-II band alignment transition in InAlAsAs/AlGaAs/GaAs self-assembled quantum dots (QDs) is investigated when the Al-composition in QDs and barrier are changed. In particular, the In0.46Al0.54As/Ga0.46Al0.54As/GaAs QDs show unique optical properties. The PL peak energy has a blue-shift of >40 meV when the laser intensity increases by four orders of magnitude, indicating a type-II band alignment of the QDs. The formation of the type-II band alignment is explained by that the quantum-confinement effect pulls up the minimum electron energy level in the QDs and the Γ→X transition in the Ga0.46Al0.54As barrier. The time-resolved PL (TRPL) spectrum of QDs at peak wavelength exhibits a double-component decay behavior, suggesting the possibility of type-I and type-II band alignment coexistence in this QD sample. The continuum state of the QDs is also investigated. Emission associated with the continuum states of the QDs is directly observed in PL spectra. The PL excitation (PLE) and TRPL spectra reveal an efficient carrier relaxation from the AlGaAs barrier into the InAlAs QD ground state via the continuum states. The carrier recombination in the continuum states can compete with that in the QDs due to the long recombination lifetime in the type-II QDs. This feature of continuum state emission can not be observed for normal InGaAs/GaAs QDs with the type-I band structure.

Paper Details

Date Published: 28 April 2017
PDF: 1 pages
Proc. SPIE 10114, Quantum Dots and Nanostructures: Growth, Characterization, and Modeling XIV, 101140N (28 April 2017); doi: 10.1117/12.2251605
Show Author Affiliations
Baolai Liang, California NanoSystem Institute (United States)
Diana L. Huffaker, California NanoSystem Institute (United States)
Yuriy I. Mazur, Univ. of Arkansas (United States)
Morgan Ware, Univ. of Arkansas (United States)
Gregory J. Salamo, Univ. of Arkansas (United States)
Linlin Su, Hebei Univ. (China)
Ying Wang, Hebei Univ. (China)
Qinglin Guo, Hebei Univ. (China)


Published in SPIE Proceedings Vol. 10114:
Quantum Dots and Nanostructures: Growth, Characterization, and Modeling XIV
Diana L. Huffaker; Holger Eisele, Editor(s)

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