Optical Properties of InGaAs Quantum Dots with GaAsSb Strain Reducing Layers
Date Issued
2012
Date
2012
Author(s)
Jhang, Han-Yun
Abstract
The optical properties of InGaAs quantum dots are investigated. A model based on linear elasticity and k‧p theory is developed to analyze the effect of shapes and composition concentrations of quantum dot, as well as GaAsSb strain reducing layers on optical properties of the InGaAs quantum dots by means of finite-element method.
The numerical results show that GaAsSb layers can release the strain field inside and in the neighborhood of InGaAs quantum dots. When the thickness of GaAsSb layer is greater than the height of quantum dot, the strain relaxation is higher. Moreover, by using GaAsSb as buffer and capping layer simultaneously, strain will be released most. Both GaAsSb layer thickness and the order of epitaxy will influence the optical properties, and the effect are more obvious when the thickness of GaAsSb strain reducing layer is less than the quantum-dot height. For Sb content > 0.16, the transition way of the quantum dot transfers from type I to type II, and the red-shift of transition energy increases as Sb content increases.
The calculated results also indicate that the AlGaAs layer can increase quantum confinement. The number of electron-energy-state confined in the quantum dot increases as the quantum dot size increases, and optical properties are more sensitive to the quantum-dot height. Excessively high quantum dot causes the wave-function overlaps to decrease. For high indium concentration quantum dots, the range of quantum-dot size with high optical gain is narrow.
Subjects
quantum dot
GaAsSb
strain reducing layer
finite element method
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
index.html
Size
23.49 KB
Format
HTML
Checksum
(MD5):f6fbb63194e19f4cd53275f98ed7a6cb