Download or read book Optical Properties of Gallium Arsenide based Self assembled Quantum Dots and Quantum Dot Lasers written by Karin Hinzer and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three-dimensional confinement of carriers eliminates the problem of thermal spreading of carriers observed in higher-dimensional systems. Uniform self-assembled quantum dots (QDs) are obtained using the spontaneous islanding of highly strained III-V semiconductors grown with standard epitaxy. Visible stimulated emission has been obtained with red-emitting AlInAs QDs in AlGaAs barriers. Continuous (CW) threshold current densities below 100A/cm2 have been measured at low temperatures and QD material gain larger than 1.7 x 104 cm-1 demonstrate good material quality. Room temperature lasing has also been observed for higher threshold current densities. For longer wavelengths where the thermionic emission problem is less important, InAs/GaAs lasers can operate at room temperature for current densities below 100A/cm2 for wavelengths around 950 nm. The zero-dimensional transitions between confined electrons and holes in artificial atoms allow the observation of state-filling at relatively low level of material excitation. Lasing is observed in the upper QD shells for small gain media, and progress towards the QD ground states for longer cavity lengths. Gain may also be increased by including multiple layers of QDs in the active region. To understand the shell structure of AlInAs/AlGaAs QDs, we present results of interband spectroscopy of single Al0.36In0.64As/Al 0.33Ga0.67As self-assembled QDs. The single dot spectroscopy has been carried out at low temperature as a function of the excitation power and magnetic field up to 8 T. The emission spectra as a function of excitation power show two distinct groups of transitions which we associate with the recombination from ground and excited QD levels with a spacing of 70 meV. The application of magnetic field allows to identify the exciton emission as well as the emission from the bi-exciton, and charged exciton complexes with binding energies of 5 meV. The binding energies compare favorably with results of calculations. Artificial molecules are studied using coupled QD ensembles and single QD spectroscopy. The coupling between the zero-dimensional states is varied by changing the distance between two layers of stacked InAs/GaAs QDs. Energy level splitting larger than 30 meV of the symmetric and anti-symmetric states of the lowest confined shell are measured and are compared to theory.
Download or read book Optical Properties of GaAs based Self assembled Quantum Dots and Quantum Dot Lasers written by Karin Hinzer and published by . This book was released on 2001 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Self Assembled InGaAs GaAs Quantum Dots written by and published by Academic Press. This book was released on 1999-03-29 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Self Assembled InGaAs GaAs Quantum Dots written by and published by Academic Press. This book was released on 1999-04-05 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Self Assembled Quantum Dots written by Zhiming M Wang and published by Springer Science & Business Media. This book was released on 2007-11-29 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: This multidisciplinary book provides up-to-date coverage of carrier and spin dynamics and energy transfer and structural interaction among nanostructures. Coverage also includes current device applications such as quantum dot lasers and detectors, as well as future applications to quantum information processing. The book will serve as a reference for anyone working with or planning to work with quantum dots.
Download or read book Quantum Dot Lasers written by Victor Mikhailovich Ustinov and published by . This book was released on 2003 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book addresses issues associated with physics and technology of injection lasers based on self-organized quantum dots. Fundamental and technological aspects of quantum dot edge-emitting lasers and VCSELs, their current status and future prospects are summarized and reviewed. Basic principles of QD formation using self-organization phenomena are reviewed. Structural and optical properties of self-organized QDs are considered with a number of examples in different material systems. Recent achievements in controlling the QD properties including the effects of vertical stacking, changing the matrix bandgap and the surface density of QDs are reviewed. The authors focus on the use of self-organized quantum dots in laser structures, fabrication and characterization of edge and surface emitting diode lasers, their properties and optimization with special attention paid to the relationship between structural and electronic properties of QDs and laser characteristics. The threshold and power characteristics of the state-of-the-art QD lasers are demonstrated. Issues related to the long-wavelength (1.3-mm) lasers on a GaAs substrate are also addressed and recent results on InGaAsN-based diode lasers presented for the purpose of comparison.
Download or read book Quantum Dots written by Elena Borovitskaya and published by World Scientific. This book was released on 2002-07-08 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Quantum Dots written by Michael Shur and published by World Scientific. This book was released on 2002 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Study of Nonlinear Optical Properties of Indium Arsenide gallium Arsenide and Indium Gallium Arsenide gallium Arsenide Self assembled Quantum Dots written by Syed Hassan Shah and published by ProQuest. This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structural and Optical Properties of Self assembled Indium Gallium Arsenide Quantum Dots written by Didik Aryanto and published by . This book was released on 2009 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical and Electrical Properties of Single Self Assembled Quantum Dots in Lateral Electric Fields written by Malte Huck and published by diplom.de. This book was released on 2010-03-25 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 [...]
Download or read book Structural Optical and Spectral Behaviour of InAs based Quantum Dot Heterostructures written by Saumya Sengupta and published by Springer. This book was released on 2017-08-04 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the effects of growth pause or ripening time on the properties of quantum dots(QDs). It covers the effects of post-growth rapid thermal annealing (RTA) treatment on properties of single layer QDs. The effects of post-growth rapid thermal annealing (RTA) treatment on properties of single layer QDs are discussed. The book offers insight into InAs/GaAs bilayer QD heterostructures with very thin spacer layers and discusses minimum spacer thickness required to grow electronically coupled bilayer QD heterostructures. These techniques make bilayer QD heterostructures a better choice over the single layer and uncoupled multilayer QD heterostructure. Finally, the book discusses sub-monolayer (SML) growth technique to grow QDs. This recent technique has been proven to improve the device performance significantly. The contents of this monograph will prove useful to researchers and professionals alike.
Download or read book Fingerprints in the Optical and Transport Properties of Quantum Dots written by Ameenah Al-Ahmadi and published by BoD – Books on Demand. This book was released on 2012-06-13 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book "Fingerprints in the optical and transport properties of quantum dots" provides novel and efficient methods for the calculation and investigating of the optical and transport properties of quantum dot systems. This book is divided into two sections. In section 1 includes ten chapters where novel optical properties are discussed. In section 2 involve eight chapters that investigate and model the most important effects of transport and electronics properties of quantum dot systems This is a collaborative book sharing and providing fundamental research such as the one conducted in Physics, Chemistry, Material Science, with a base text that could serve as a reference in research by presenting up-to-date research work on the field of quantum dot systems.
Download or read book Quantum Dot Lasers written by and published by . This book was released on 2003 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantum Dots Fundamentals Applications and Frontiers written by Bruce A. Joyce and published by Springer Science & Business Media. This book was released on 2006-03-30 with total page 401 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains papers delivered at a NATO Advanced Research Workshop and provides a broad introduction to all major aspects of quantum dot structures. Such structures have been produced for studies of basic physical phenomena, for device fabrication and, on a more speculative level, have been suggested as components of a solid-state realization of a quantum computer. The book is structured so that the reader is introduced to the methods used to produce and control quantum dots, followed by discussions of their structural, electronic, and optical properties. It concludes with examples of how their optical properties can be used in practical devices, including lasers and light-emitting diodes operating at the commercially important wavelengths of 1.3 Am and 1.55 Am."
Download or read book Semiconductor Quantum Dots written by Yasuaki Masumoto and published by Springer Science & Business Media. This book was released on 2002-05-28 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: Growth of Self Organized Quantum Dots / J.-S. Lee / - Excitonic Structures and Optical Properties of Quantum Dots / Toshihide Takagahara / - Electron-Phonon Interactions in Semiconductor Quantum Dots / Toshihide Takagahara / - Micro-Imaging and Single Dot Spectroscopy of Self Assembled Quantum Dots / Mitsuru Sugisaki / - Persistent Spectral Hole Burning in Semiconductor Quantum Dots / Yasuaki Masumoto / - Dynamics of Carrier Relaxation in Self Assembled Quantum Dots / Ivan V. Ignatiev, Igor E. Kozin / - Resonant Two-Photon Spectroscopy of Quantum Dots / Alexander Baranov / - Homogeneous Width of Confined Excitons in Quantum Dots - Experimental / Yasuaki Masumoto / - Theory of Exciton Dephasing in Semiconductor Quantum Dots / Toshihide Takagahara / - Excitonic Optical Nonlinearity and Weakly Correlated Exciton-Pair States / Selvakumar V. Nair, Toshihide Takagahara / - Coulomb Effects in the Optical Spectra of Highly Excited Semiconductor Quantum Dots / Selvakumar V. Nair / - Device ...
Download or read book Quaternary Capped In Ga As GaAs Quantum Dot Infrared Photodetectors written by Sourav Adhikary and published by Springer. This book was released on 2017-09-06 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces some alternative methods for enhancing the performance of In(Ga)As/GaAs-based quantum dot infrared photodetectors (QDIPs). In(Ga)As/GaAs-based QDIPs and focal plane array (FPA) cameras have wide application in fields such as military and space science. The core of the study uses a combination of quaternary In0.21Al0.21Ga0.58As and GaAs spacer as a capping layer on In(Ga)As/GaAs quantum dots in the active region of the detector structure. For the purposes of optimization, three types of samples growths are considered with different capping thicknesses. The results presented include TEM, XRD and photoluminescence studies that compare combination barrier thickness and its effect on structural and optical properties. Compressive strain within the heterostructure, thermal stability in high temperature annealing, spectral response, shifts in PL peaks peak,and responsivity and detectivity are all considered. The results also present a narrow spectral width that was obtained by using InAs QDs which is very useful for third generation FPA camera application. The book details effect of post-growth rapid thermal annealing on device characteristics and methods to enhance responsivity and peak detectivity. The contents of this book will be useful to researchers and professionals alike.
