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Proceedings Paper

Investigation of various capping layer configuration on heterogeneously coupled SML on SK quantum dots heterostructure
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Paper Abstract

Hybrid coupled quantum dot (QD) structures have a high absorption coefficient along with the minimum cumulative strain in the heterostructure compared to that in the homogeneously coupled heterostructure of only Stranski-Krastanov (SK) QDs. Here, we are introducing a theoretical analysis of the hybrid heterostructure consisting of six submonolayer (SML) stacks above SK QDs with a various capping layer combinations. Sample A (InGaAs-InGaAs) has both SK and SML capping layers of InGaAs. Similarly, Sample B (InGaAsInAlGaAs), sample C (InAlGaAs-InGaAs), and sample D (InAlGaAs-InAlGaAs) have variations in the capping composition of SK and SML dots. The barrier thickness between SML stacks and SK dots is taken to be 7.5nm, and the capping layer thickness of the SK dot is 3nm. The number of SML stacks and barrier thickness has been optimized from our previous experimental work. Hydrostatic and biaxial strains of four samples are analyzed and compared. It has been found that sample D shows the lowest magnitude of hydrostatic strain in both SML and SK dots, suggesting better carrier confinement in both QDs. Moreover, Sample D has the highest biaxial strain in the SK dot indicating the maximum splitting of the valence band which leads to a lower band gap in the sample. Thus, after optimizing all the performance parameters, we found that Sample D could be the potential candidate for optoelectronic device applications.

Paper Details

Date Published: 9 September 2019
PDF: 8 pages
Proc. SPIE 11085, Low-Dimensional Materials and Devices 2019, 1108517 (9 September 2019); doi: 10.1117/12.2528893
Show Author Affiliations
Pravin Raut, Indian Institute of Technology Bombay (India)
Rajkumar Ramavath, Indian Institute of Technology Bombay (India)
Jhuma Saha, Indian Institute of Technology Bombay (India)
Debabrata Das, Indian Institute of Technology Bombay (India)
Debiprasad Panda, Indian Institute of Technology Bombay (India)
Subhananda Chakrabarti, Indian Institute of Technology Bombay (India)

Published in SPIE Proceedings Vol. 11085:
Low-Dimensional Materials and Devices 2019
Nobuhiko P. Kobayashi; A. Alec Talin; Albert V. Davydov, Editor(s)

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