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Proceedings Paper

The effects of V-III ratio on structural and optical properties of self-assembled InAs quantum dots
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Paper Abstract

InAs/GaAs Quantum Dots have piqued the interest of researchers owing to the advantages they offer in the fabrication of highly efficient optoelectronic devices. In this study, we aim to examine the consequence varying V-III ratio on optical and structural behavior of self-assembled InAs/GaAs Stranski-Krastanov (SK) Quantum Dots grown on GaAs substrate using Molecular Beam Epitaxy (MBE). Three samples consisting of three layers of vertically stacked Quantum Dots with three different V-III ratios (48, 60 and 80 respectively) grown at a substrate temperature of 490°C have been thoroughly examined using PL spectroscopy and HR-XRD. The best optical response is seen in the sample with 80 as VIII ratio. A higher As vapor pressure during growth seems to suppress the surface migration of Indium atoms leading to bigger dot size, increased PL intensity and more uniform distribution rendering better optical response. The absence of satellite peaks in HR-XRD measurements of sample with lower V-III ratio indicates significant density of point-defects. HRXRD analysis reveals an increase in perpendicular strain with greater V-III ratio. Reduced FWHM in sample with higher V-III ratio is in accordance with suppressed Indium diffusion and strain propagation across multi-layered nanostructure contributing to greater uniformity in dot-size. PL spectrum of sample with least V-III ratio shows sharp peaks around 900 nm indicating incomplete dot-formation at such low ratios leaving significant part of wetting layer exposed. Our investigation provides interesting insights into kinetics of nanostructure growth which will prove to be helpful in fabrication of optimized nanostructures.

Paper Details

Date Published: 9 September 2019
PDF: 9 pages
Proc. SPIE 11085, Low-Dimensional Materials and Devices 2019, 1108518 (9 September 2019);
Show Author Affiliations
Anubhav Agarwal, Indian Institute of Technology Bombay (India)
Abhijeet Aanand, Indian Institute of Technology Bombay (India)
Sanowar A. Gazi, Indian Institute of Technology Bombay (India)
Suryansh Dongre, Indian Institute of Technology Bombay (India)
Sritoma Paul, Kalyani Government Engineering College (India)
Shubham Mondal, Kalyani Government Engineering College (India)
Rishabh A. Dahale, 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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