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Proceedings Paper

A detailed investigation of strain patterning effect on bilayer InAs/GaAs quantum dot with varying GaAs barrier thickness
Author(s): B. Tongbram; N. Sehara; J. Singhal; D. Prasad Panda; S. Chakrabarti
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Paper Abstract

In this paper, we discuss detailed strain effects on a bilayer InAs quantum dot with varying GaAs barrier thickness. The exploration of the range of GaAs barrier thickness effect on the InAs/GaAs quantum dots and detailed structure were characterized by transmission electron microscopy, atomic force microscopy, high-resolution X-Ray diffraction (HRXRD) and Raman spectroscopy to evaluate the impact of strained layer and also studied the optical properties by photoluminescence (PL) measurements. On varying the thickness of the GaAs barrier layer, the role of strain demonstrates a promising approach to tuning the quantum dot morphologies and structures and hence, optical properties. This can be easily observed from the HRXRD rocking curves which result in a shift of the zero order peak position. Both in-out-plane strain decrease as the thickness is increased. Even the Raman scattering peaks justify the decrease of strain on increasing the GaAs barrier thickness. Therefore, higher strain propagation indicates redshift in the emission wavelength and the dots are much more uniformly spread out. Structure with a range of 5.5nm-8.5nm GaAs barrier thickness interlayer reveals even high-quality crystallinity of the epilayers with the FWHM of 21.6 arcsecs for the (004) reflection. Uncoupled structure responses low crystalline quality with FWHM of 109 arcsecs. Dislocation density increases drastically with a decrease of strain which is an important aspect of lasers and other devices in increasing their efficiency. Activation energy also shows a positive correlation with coupling structure. Therefore, controlling diffusion length may be key to reducing defects in several strained structures.

Paper Details

Date Published: 15 March 2016
PDF: 9 pages
Proc. SPIE 9758, Quantum Dots and Nanostructures: Growth, Characterization, and Modeling XIII, 975802 (15 March 2016); doi: 10.1117/12.2212767
Show Author Affiliations
B. Tongbram, Indian Institute of Technology Bombay (India)
N. Sehara, Indian Institute of Technology Bombay (India)
J. Singhal, Indian Institute of Technology Bombay (India)
D. Prasad Panda, Indian Institute of Technology Bombay (India)
S. Chakrabarti, Indian Institute of Technology Bombay (India)


Published in SPIE Proceedings Vol. 9758:
Quantum Dots and Nanostructures: Growth, Characterization, and Modeling XIII
Diana L. Huffaker; Holger Eisele; Kimberly A. Dick, Editor(s)

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