Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 49
Book Description
Optical Response of Quantum Dots Embedded in a Quantum Wire
Author: Semiconductor Quantum Dots
Author: Y. MasumotoPublisher: Springer Science & Business Media
ISBN: 3662050013
Category : Technology & Engineering
Languages : en
Pages : 500
Book Description
Semiconductor quantum dots represent one of the fields of solid state physics that have experienced the greatest progress in the last decade. Recent years have witnessed the discovery of many striking new aspects of the optical response and electronic transport phenomena. This book surveys this progress in the physics, optical spectroscopy and application-oriented research of semiconductor quantum dots. It focuses especially on excitons, multi-excitons, their dynamical relaxation behaviour and their interactions with the surroundings of a semiconductor quantum dot. Recent developments in fabrication techniques are reviewed and potential applications discussed. This book will serve not only as an introductory textbook for graduate students but also as a concise guide for active researchers.
Optics of Quantum Dots and Wires
Author: Garnett W. BryantPublisher: Artech House Publishers
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 574
Book Description
Quantum technology is the key to next-generation optoelectronics and laser semiconductors, and this new cutting-edge book is an in-depth examination of how quantum dots and wires are fabricated and applied to optics. You find a solid tutorial on the optical properties of nanoscale dots and wires that explains the current state of this technology and why it is so promising. The book presents a detailed survey of techniques based on molecular beam epitaxial growth for fabricating semiconductor quantum dots and wires. You learn how to assess these growth strategies for insertion of dots and wires into devices.
Electronic and Optical Properties of Quantum Dots and Wires
Author: Oliver StierPublisher:
ISBN: 9783896853660
Category : Nanowires
Languages : en
Pages : 190
Book Description
Optical and Electrical Properties of Single Self-Assembled Quantum Dots in Lateral Electric Fields
Author: Malte HuckPublisher: diplom.de
ISBN: 3836644398
Category : Science
Languages : en
Pages : 137
Book Description
Inhaltsangabe:Abstract: Chapter 1: In this thesis we investigate the optical properties of self-assembled quantum dots exposed to a lateral electric field. As a result of the electric field the wave functions of electrons and holes inside the quantum dot are manipulated, which makes it possible to tune their energy levels and control the optical properties of the system. The possibility of tuning the emission energy of different few particle states using this method makes this system very promising for the use of a source of polarization entangled photons as discussed in the following sections. In Section 1.1 the concept of entangled states is introduced together with a brief historical overview. The possibility of using the exciton biexciton cascade of a self-assembled quantum dot for the generation of entangled photon pairs is presented in Section 1.2. Chapter 2: In this chapter we introduce the concept of quantum dots and demonstrate their optical emission properties. In Section 2.1 the quantum dot is introduced as a three-dimensional charge carrier trap. Several types of quantum dots are presented in an overview. In Section 2.2 we discuss the physical effects that occur on the way from bulk semiconductor material to the three-dimensional charge carrier confinement in the case of quantum dots. The growth of self-assembled quantum dot samples is the topic of Section 2.3, where the technique of molecular beam epitaxy is introduced (Section 2.3.1). This technique is used to grow the semiconductor quantum dots via heteroepitaxy in the Stranski-Krastanov growth mode (Section 2.3.2). Quantum dots are commonly referred to as artificial atoms due to their atomlike emission features. The origin for this expression is explained in Section 2.4 on the basis of the energetic structure of self-assembled quantum dots. The optical properties of quantum dots are discussed in Section 2.5, beginning with an introduction to the experimental setup that has been used to investigate the quantum dots during this thesis (Section 2.5.1). Different optical excitation modes are presented in Section 2.5.2 and in Section 2.5.3 we discuss, how to achieve a low enough quantum dot density on the analyzed samples. Section 2.5.4 deals with the photoluminescence of different exciton states and in Section 2.5.5 we present how these lines can be identified via power dependent measurements. Finally, the concept of initial charges in self-assembled quantum dots is presented in [...]
The Optical Response of Semiconductor Self-Assembled Quantum Dots
Author: Zhifeng WeiPublisher: Open Dissertation Press
ISBN: 9781374667525
Category :
Languages : en
Pages :
Book Description
This dissertation, "The Optical Response of Semiconductor Self-assembled Quantum Dots" by Zhifeng, Wei, 魏志鋒, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled THE OPTICAL RESPONSE OF SEMICONDUCTOR SELF-ASSEMBLED QUANTUM DOTS Submitted by Wei Zhifeng for the degree of Doctor of Philosophy at The University of Hong Kong in May 2006 Self-assembled quantum dots (QDs) are one type of tiny coherent islands which spontaneously form via the Stranski-Krastanow (S-K) growth mode during the heteroepitaxial growth of lattice-mismatched thin films. They have attracted considerable interest in recent years because of their atom-like properties and many potential applications in novel electronic and photonic devices. A detailed investigation on the optical properties of semiconductor QDs was presented in this thesis project. The variable-temperature photoluminescence (PL) spectra of two kinds of InGaAs QDs with and without a GaAs cap layer were comparatively investigated. It was found that the optical properties of the buried QDs with the cap layer differ significantly from those of the surface QDs. The growth of cap layer can improve the dots uniformity indicated by the narrow PL peak, greatly enhance the luminescence efficiency, and result in a large blueshift of the emission peak due to the strain environment change of the QDs. The cap layer also improves the thermal stability of the QD emission. The spontaneous emission mechanisms of two quaternary self-assembled GaInAsN QDs with different compositions and growth thicknesses have been studied. Adopting a newly developed localized-states luminescence model, the temperature behavior of the emissions from the two GaInAsN QDs has been quantitatively interpreted. The physical pictures of the spontaneous emissions of GaInAsN QDs were established. For the self-assembled QDs, a strained thin layer underneath the QDs always exists and this two-dimensional thin layer is called the wetting layer (WL). A quantitative study on the role of WL in the luminescence process of InAs/GaAs self- assembled QDs has been conducted. It has been shown that the WL acts as an efficient bridge not only in the relaxation of carriers from the barrier layer to the QDs but also in the thermal escaping of the carriers already captured by the QDs. Since the knowledge of electronic structure and optical transitions of self- assembled QDs is essentially important for the infrared detection applications of the QDs, a precise PL spectroscopic probe of the electronic structures of InAs/GaAs QDs with various silicon doping concentrations has been carried out. The theoretical predicted blueshift of the fundamental transitions of the QDs has been observed as the Si doping concentration and thus the number of electrons loaded into the dot is increased. It was also found that the Si δ-doping at the central regions of barrier layers during the growth of multi-layered QDs can significantly improve the luminescence efficiency of the samples at higher temperatures. Growth and optical characterizations of the electrically coupled InAs and InP QD stacking structures have been done. The study provides a possible way to produce a new type of broad-band QD light emitting diodes via the so-called band-engineering method. DOI: 10.5353/th_b3709820 Subjects: Quantum dots Semiconductors - Optical properties
The Optical Response of Semiconductor Self-assembled Quantum Dots
Author: Zhifeng WeiPublisher:
ISBN:
Category : Quantum dots
Languages : en
Pages : 274
Book Description
Self-Assembled InGaAs/GaAs Quantum Dots
Author: Publisher: Academic Press
ISBN: 0080864589
Category : Technology & Engineering
Languages : en
Pages : 385
Book Description
This volume is concerned with the crystal growth, optical properties, and optical device application of the self-formed quantum dot, which is one of the major current subjects in the semiconductor research field.The atom-like density of states in quantum dots is expected to drastically improve semiconductor laser performance, and to develop new optical devices. However, since the first theoretical prediction for its great possibilities was presented in 1982, due to the difficulty of their fabrication process. Recently, the advent of self-organized quantum dots has made it possible to apply the results in important optical devices, and further progress is expected in the near future.The authors, working for Fujitsu Laboratories, are leading this quantum-dot research field. In this volume, they describe the state of the art in the entire field, with particular emphasis on practical applications.
Quantum Dots
Author: Elena BorovitskayaPublisher: World Scientific
ISBN: 9814488798
Category : Technology & Engineering
Languages : en
Pages : 214
Book Description
In this book, leading experts on quantum dot theory and technology provide comprehensive reviews of all aspects of quantum dot systems. The following topics are covered: (1) energy states in quantum dots, including the effects of strain and many-body effects; (2) self-assembly and self-ordering of quantum dots in semiconductor systems; (3) growth, structures, and optical properties of III-nitride quantum dots; (4) quantum dot lasers.
Quantum Dots
Author: Michael ShurPublisher: World Scientific
ISBN: 9810249187
Category : Science
Languages : en
Pages : 214
Book Description
In this book, leading experts on quantum dot theory and technology provide comprehensive reviews of all aspects of quantum dot systems. The following topics are covered: (1) energy states in quantum dots, including the effects of strain and many-body effects; (2) self-assembly and self-ordering of quantum dots in semiconductor systems; (3) growth, structures, and optical properties of III-nitride quantum dots; (4) quantum dot lasers.