Time-resolved photoluminescence spectra of self-assembled InAs/GaAs quantum dots
Resource
Thin Solid Films 498 (2006)188-192
Journal
Thin Solid Films
Journal Issue
498
Pages
-
Date Issued
2006
Date
2006
Author(s)
Kong, Ling-Min
Cai, Jia-Fa
Wu, Zheng-Yun
Gong, Zheng
Niu, Zhi-Chuan
Feng, Zhe-Chuan
DOI
246246/2006111501243754
Abstract
Two types of InAs self-assembled Quantum dots (QDs) were prepared by Molecular beam epitaxy. Atomic force microscopy (AFM)
measurements showed that, compared to QDs grown on GaAs substrate, QDs grown on InGaAs layer has a significantly enhanced density.
The short spacing (several nanometer) among QDs stimulates strong coupling and leads to a large red-shift of the 1.3 Am photoluminescence
(PL) peak. We study systematically the dependence of PL lifetime on the QDs size, density and temperature (T). We found that, below 50 K,
the PL lifetime is insensitive to temperature, which is interpreted from the localization effects. As T increases, the PL lifetime increases,
which can be explained from the competition between the carrier redistribution and thermal emission at higher temperature. The increase of
carriers in QDs migrated from barriers and wetting layer (WL), and the redistribution of carriers among QDs enhance the PL lifetime as T
increases. The thermal emission and non-radiative recombination have effects to reduce the PL lifetime at higher T. As a result, the radiative
recombination lifetime is determined by the wave function overlapping of electrons and holes in QDs, and QDs with different densities have
different PL lifetime dependence on the QDs size.
Subjects
Time-resolved photoluminescence
InAs self-assembled QDs
Migration of carriers
Publisher
Taipei:National Taiwan University Coll Elect Engn
Type
journal article
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