Atomistic Modeling of an experimental GaAs / InGaAs Quantum Dot Molecule using NEMO 3 - D Yui - Hong

..............................................................................................1 1. NEMO 3-D............................................................................................2 2. INTRODUCTION TO QUANTUMDOTS......................................................7 3. QUANTUM CONFINED STARK EFFECT.....................................................9 3.1 QCSE in single quantum dots....................................................................9 3.2 QCSE in vertically stacked quantum dots...................................................12 4. ATOMISTIC MODELING OF AN EXPERIMENTAL GaAs/InGaAs QUANTUM DOT MOLECULE USING NEMO 3-D.........................................19 4.1. Abstract..........................................................................................19 4.2 Introduction......................................................................................20 4.2.1 Motivation and Background of Problem................................................20 4.2.2 Past Studies of Piezoelectric Effects.....................................................22 4.2.3 NEMO 3-D Simulator.....................................................................23 4.2.4 Simulated Geometry.......................................................................24 4.3 Results............................................................................................26 4.3.1 Experimental Emission from Excited States..............................................26 4.3.2 Observations of Anti-Crossings within the experimental field range..................27 4.3.3 Electronic Spectrum Spectroscopy.........................................................29 5. IMPACT OF PIEZOELECTRICITY............................................................36 5.1 Energy Spectrum Without and With Piezoelectricity..........................................36 5.2 Piezoelectric Model.............................................................................40 5.3 Quadrupole Nature of the Piezoelectric Potentials.........................................41 5.4 Quantitative Explanation of ‘One’ vs. ‘Two’ Anti-Crossings.............................44 6. CONCLUSION.....................................................................................47 LIST OF REFERENCES.............................................................................49