Semiconductor quantum dots : intraband electronic, optical and carrier dynamical properties
Year: 2014
Type: dissertation
Abstract: Brief fabricational and applications surveys on semiconductor quantum dots and the subsequent motivation for further development of theoretical modeling are presented. In order to study the electronic structure of quantum dots, k • p models are introduced. Both the 8 band k • p model and the effective mass model were used in order to study electronic structure of quantum rods. Existence of bound state in continuum in quantum rods is demonstrated. The vibrational structure and electron–phonon interaction in semiconductor quantum dots was studied via bulk models for self assembled quantum dots and continuum models for colloidal quantum dots. The concept of polarons due to very strong electron–longitudinal optical phonon interaction was demonstrated for single self assembled quantum dot and for supercrystal of colloidal quantum dots. Lattice anharmonicity is also considered as a main mechanism enabling the non-radiative relaxation process of the polarons in self assembled quantum dots. Optical properties of such 3D confinement structures are modeled using dipole Hamiltonian approximation and properly incorporated into k•p model formalism within the framework of linear response theory. Radiative and non-radiative lifetimes in self assembled quantum dots were studied and correlation between them was established. Transport properties of colloidal quantum dot supercrystals were also studied within the framework of linear response theory. Variational polaron theory is introduced in order to examine formation of polarons dependent on temperature, interdot coupling strength and strengths of electron–phonon interactions. It was found that small polaron formation occurs at room temperature for possible interdot couplings. It was also found that small polaron formation narrows the bands and localizes the carriers inside each dot in the supercrystal. Available experimental data on the issue were discussed by using the results of the model.
Author: Nikola Prodanović
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: University of Leeds
OpenAlex ID: W1513232619