Investigation of Exciton Dynamics to Confirm Coupling Effects Using a Comparison between Ensemble and Single Laterally-Coupled GaAs Quantum Dot Molecules

Authors
Kim, HeedaeCha, Se-yeounSong, JindongKim, Jongsu
Issue Date
2024-04
Publisher
Wiley - V C H Verlag GmbbH & Co.
Citation
physica status solidi (a) - applications and materials science
Abstract
Herein, time-integrated and time-resolved photoluminescence (PL) measurement experiments are performed on coupled GaAs quantum dot (QD) molecules with larger laser spot size and a single-coupled QD molecule to investigate the dynamics of exciton states. A linearly polarized laser along the coupled direction of a laterally-coupled GaAs QD molecule [11 over bar $\overset{\cdot}{1}$0] is used to determine the coupling effects of the different exciton states. For the ensemble of coupled QD molecules, the exciton PL peak shifts to lower energy (approximate to 70 meV) and shows a linear increase in the PL intensity, demonstrating the properties of exciton states as a function of the laser excitation power. In addition, a power-dependent redshift is observed in the single-coupled GaAs QD molecule as a function of the excitation power; however, the two distinguished exciton states become resolved and show different power factors when the laser excitation power is linearly increased. This result clearly indicates the presence of energy transfer between the two different exciton states, X1 and X2. Furthermore, when the polarized laser excitation power is increased, a coupled biexciton consisting of two different localized exciton states (X1 and X2) is clearly observed, and a power-dependent spectral redshift is detected in the exciton and biexciton states. At a high excitation power (15 I0), the decay times of the two different localized exciton states clearly show different lifetimes; and the decay time difference due to the size difference can be ignored at a low excitation power. Theoretically, the decay times of the two different exciton states, wherein the size deviation can be ignored, should be the same. Based on the results of the time-integrated and time-resolved PL measurements and the comparison between the ensemble and single exciton PL peaks, it is concluded that the coupling process in laterally-coupled GaAs QD molecules is strongly supported against long-range separation. Herein, time-integrated and time-resolved photoluminescence (PL) measurement experiments are performed on coupled GaAs quantum dot (QD) molecules with larger laser spot size and a single-coupled QD molecule to investigate the dynamics of exciton states. A linearly polarized laser along the coupled direction of a laterally-coupled GaAs QD molecule is used to determine the coupling effects of the different exciton states.image (c) 2024 WILEY-VCH GmbH
Keywords
TRANSITIONS; biexcitons; coupled quantum dots; decay rates; excitons; photoluminescence
ISSN
1862-6300
URI
https://pubs.kist.re.kr/handle/201004/149737
DOI
10.1002/pssa.202300662
Appears in Collections:
KIST Article > 2024
Files in This Item:
There are no files associated with this item.
Export
RIS (EndNote)
XLS (Excel)
XML

qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

BROWSE