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Spie Press Book

Fundamental Absorption of Semiconductor Quantum Dots
Author(s): David Boris Hayrapetyan; Hayk A. Sarkisyan; Eduard M. Kazaryan
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Book Description

This Spotlight describes the process of fundamental absorption in a variety of quantum dot (QD) geometries, such as spherical, cylindrical, ellipsoidal, lens-shaped, conical, and spherical layered, including in the presence of external fields. Other topics include the effect of exciton effects on the interband absorption coefficients and the application of QD ensembles in QD-LED devices. The mathematics involved is presented with as much detail as possible, and readers need only be familiar with semiconductor physics and quantum mechanics.

Book Details

Date Published: 16 November 2018
Pages: 77
ISBN: 9781510623019
Volume: SL43

Table of Contents
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1 Introduction

2 Fundamental Absorption in Quantum Dots
2.1 Spherical quantum dot
     2.1.1 Strong size quantization regime
     2.1.2 Weak size quantization regime
     2.1.3 Intermediate size quantization regime
2.2 Cylindrical quantum dot
     2.2.1 Energy spectrum and wave function
     2.2.2 Direct interband absorption
     2.2.3 Excitonic effects
2.3 Conical quantum dot
     2.3.1 Energy spectrum and wave function
     2.3.2 Direct interband absorption
2.4 Ellipsoidal quantum dot
     2.4.1 Energy spectrum and wave function
     2.4.2 Direct interband absorption
2.5 Lens-shaped quantum dot
2.6 Spherical layered quantum dot
     2.6.1 Energy spectrum and wave function
     2.6.2 Interband absorption

3 Effects of a Magnetic Field on the Absorption Spectra
3.1 Interband transitions in the absence of a magnetic field
3.2 Effect of a magnetic field on the interband transitions
3.3 Normal-modes approach

4 Effects of an Electric Field on the Absorption Spectra
4.1 Energy spectrum and wave function
4.2 Direct interband absorption

5 Conclusion


This Spotlight describes the mechanism of fundamental absorption in different types of quantum dots (QDs). The detailed discussion of the absorption mechanism in the spherical QD is presented for three regimes of size quantization (strong, weak, and intermediate). The same calculations are done for the cylindrical, ellipsoidal, conical, and spherical nanolayered QDs, taking into account the specific forms of the mentioned structures. Absorption of long-wave radiation by electron gas localized in a lens-shaped QD is considered as an example of the multiparticle optical effect. The dependence of the threshold frequencies on the geometrical sizes is plotted for each type of QD. Selection rules for interband transitions between quantum levels are revealed. The effects of external magnetic and electric fields on the absorption spectra and selection rules are presented. The problem of the application of ensembles of QDs in QD-light-emitting-diode devices is discussed.

David B. Hayrapetyan
Hayk A. Sarkisyan
Eduard M. Kazaryan
October 2018

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