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Thermal stability of quaternary alloy (InAlGaAs)-capped InAs/GaAs multilayer quantum dot heterostructures with variation in growth rate, barrier thickness, seed quantum dot monolayer coverage, and post-growth annealing

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Title Thermal stability of quaternary alloy (InAlGaAs)-capped InAs/GaAs multilayer quantum dot heterostructures with variation in growth rate, barrier thickness, seed quantum dot monolayer coverage, and post-growth annealing
 
Creator MANDAL, A
VERMA, U
CHAKRABARTI, S
 
Subject CHEMICAL-VAPOR-DEPOSITION
THRESHOLD CURRENT-DENSITY
TEMPERATURE
LASER
 
Description Strain-driven influences on the structural and optoelectronic properties of self-assembled InAs/GaAs multilayer quantum dot (MQD) heterostructures prompted our research into the growth of thermally stable MQD samples that were functional in an emission range technically favorable for communication lasers and intermediate band gap solar cells. We also studied parameter optimization by varying growth rate, capping layer thickness, seed quantum dot (QD) monolayer coverage, and post-growth annealing. A capping combination of InAlGaAs and i-GaAs was used. This combination helps in strain compensation, favors growth of multiple QD layers, functions as a strain-driven phase separation alloy, and helps increase QD stability. Photoluminescence results showed MQD sample emissions in the technologically significant range of 1.1-1.3 mu m. Post-growth annealing at high temperatures led to inter-diffusion of the constituent QD materials, generation of low minimum energy states, and greater carrier involvement in intermediate band gap structures, thereby showing that annealing is a suitable method for post-growth manipulation. For one MQD sample, the annealing temperature was found to affect structural and optoelectronic properties as well as the presence of intermediate energy states. Heterostructure stability at annealing temperatures up to 750 C-a similar to was found for the other samples. Transmission electron microscopy and photoluminescence results supported these findings.
 
Publisher SPRINGER
 
Date 2014-10-15T16:54:14Z
2014-10-15T16:54:14Z
2013
 
Type Article
 
Identifier APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 113(1)215-220
http://dx.doi.org/10.1007/s00339-012-7521-2
http://dspace.library.iitb.ac.in/jspui/handle/100/15261
 
Language en