Carrier recombination dynamics in electronically coupled multi-layer InAs/GaAs quantum dots

Optical properties of multi-layer InAs/GaAs quantum dots (QDs) with different GaAs spacer layer thicknesses (dGaAs) of 20, 15 and 10nm are investigated by time-integrated and time-resolved photoluminescence (PL) spectroscopy. The energy spacing between ground and excited state is observed to be decr...

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Bibliographic Details
Published in:Journal of luminescence 2018-03, Vol.195, p.109-115
Main Authors: Mohanta, Antaryami, Jang, Der-Jun, Lu, Shu-Kai, Ling, Dah-Chin, Wang, J.S., Chen, R.-B., Chuang, F.-C.
Format: Article
Language:English
Subjects:
Carrier dynamics
InAs/GaAs quantum dots
Phonon bottleneck effect
Photoluminescence
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Summary:Optical properties of multi-layer InAs/GaAs quantum dots (QDs) with different GaAs spacer layer thicknesses (dGaAs) of 20, 15 and 10nm are investigated by time-integrated and time-resolved photoluminescence (PL) spectroscopy. The energy spacing between ground and excited state is observed to be decreased with decrease in dGaAs and increased with increase in excitation intensity. The rate of carrier capture and energy relaxation in QDs is found to be slower at excitation energy of 3.06eV than that at 1.53eV which is attributed to intervalley scattering in GaAs. The effect of intervalley scattering process in GaAs on decay time is negligible for dGaAs of 20nm and is prominent for dGaAs ≤ 15nm.
ISSN:0022-2313
1872-7883
DOI:10.1016/j.jlumin.2017.11.009