Download or read book Investigations of Electronic States in Self assembled INAS GAAS Quantum dot Structures written by Shiwei Lin and published by . This book was released on 2006 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theoretical and Experimental Studies of Electronic States in Inas GAAS Self Assembled Quantum Dots written by Yuan Wen and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Theoretical and experimental studies of electronic states in InAs/GaAs self-assembled quantum dots" by Yuan, Wen, 文苑, 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. DOI: 10.5353/th_b4322400 Subjects: Gallium arsenide semiconductors Indium alloys Quantum dots
Download or read book Theoretical and Experimental Studies of Electronic States in InAs GaAs Self assembled Quantum Dots written by Yuan Wen (physicist.) and published by . This book was released on 2009 with total page 124 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 Impact of Ion Implantation on Quantum Dot Heterostructures and Devices written by Arjun Mandal and published by Springer. This book was released on 2017-06-02 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book looks at the effects of ion implantation as an effective post-growth technique to improve the material properties, and ultimately, the device performance of In(Ga)As/GaAs quantum dot (QD) heterostructures. Over the past two decades, In(Ga)As/GaAs-based QD heterostructures have marked their superiority, particularly for application in lasers and photodetectors. Several in-situ and ex-situ techniques that improve material quality and device performance have already been reported. These techniques are necessary to maintain dot density and dot size uniformity in QD heterostructures and also to improve the material quality of heterostructures by removing defects from the system. While rapid thermal annealing, pulsed laser annealing and the hydrogen passivation technique have been popular as post-growth methods, ion implantation had not been explored largely as a post-growth method for improving the material properties of In(Ga)As/GaAs QD heterostructures. This work attempts to remedy this gap in the literature. The work also looks at introduction of a capping layer of quaternary alloy InAlGaAs over these In(Ga)As/GaAs QDs to achieve better QD characteristics. The contents of this volume will prove useful to researchers and professionals involved in the study of QDs and QD-based devices.
Download or read book Resolving Spin Physics in Self assembled InAs GaAs Quantum Dots written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Capture and Relaxation in Self Assembled Semiconductor Quantum Dots written by Robson Ferreira and published by Morgan & Claypool Publishers. This book was released on 2016-02-23 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an overview of different models and mechanisms developed to describe the capture and relaxation of carriers in quantum-dot systems. Despite their undisputed importance, the mechanisms leading to population and energy exchanges between a quantum dot and its environment are not yet fully understood. The authors develop a first-order approach to such effects, using elementary quantum mechanics and an introduction to the physics of semiconductors. The book results from a series of lectures given by the authors at the Master’s level.
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 Exploring Single Hole States in InAs GaAs Quantum Dots and Quantum Dot Molecules Under 2 D Electric Fields written by Xiangyu Ma and published by . This book was released on 2019 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: InAs/GaAs quantum dots (QDs) and quantum dot molecules (QDMs) are self-assembled semiconductor nanostructures that can trap a single electron or hole in a 3-D potential-well. Grown by molecular beam epitaxy (MBE), they have excellent optical qualities that can be used in applications for quantum information processing and quantum computing. Specifically, hole spins in a single QD/QDM have longer decoherence time than electron spins due to the lack of hyperfine interaction, making hole spins a great qubit candidate. However, many challenges such as QD growth, device integration, and spin manipulation inhibit the scalability of a hole-spin-based quantum information platform. A deeper understanding of the hole spin physics and the QD/QDM material system is needed to advance device engineering opportunities.
Download or read book Single Quantum Dots written by Peter Michler and published by Springer Science & Business Media. This book was released on 2003-12-09 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: Special focus is given to the optical and electronic properties of single quantum dots due to their potential applications in devices operating with single electrons and/or single photons. This includes quantum dots in electric and magnetic fields, cavity-quantum electrodynamics, nonclassical light generation, and coherent optical control of excitons.
Download or read book Self Organized Quantum Dots for Memories written by Tobias Nowozin and published by Springer Science & Business Media. This book was released on 2013-10-01 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today’s semiconductor memory market is divided between two types of memory: DRAM and Flash. Each has its own advantages and disadvantages. While DRAM is fast but volatile, Flash is non-volatile but slow. A memory system based on self-organized quantum dots (QDs) as storage node could combine the advantages of modern DRAM and Flash, thus merging the latter’s non-volatility with very fast write times. This thesis investigates the electronic properties of and carrier dynamics in self-organized quantum dots by means of time-resolved capacitance spectroscopy and time-resolved current measurements. The first aim is to study the localization energy of various QD systems in order to assess the potential of increasing the storage time in QDs to non-volatility. Surprisingly, it is found that the major impact of carrier capture cross-sections of QDs is to influence, and at times counterbalance, carrier storage in addition to the localization energy. The second aim is to study the coupling between a layer of self-organized QDs and a two-dimensional hole gas (2DHG), which is relevant for the read-out process in memory systems. The investigation yields the discovery of the many-particle ground states in the QD ensemble. In addition to its technological relevance, the thesis also offers new insights into the fascinating field of nanostructure physics.
Download or read book Next Generation Photovoltaics written by A. Martí and published by CRC Press. This book was released on 2003-09-01 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although photovoltaics are regarded by many as the most likely candidate for long term sustainable energy production, their implementation has been restricted by the high costs involved. Nevertheless, the theoretical limit on photovoltaic energy conversion efficiency-above 85%-suggests that there is room for substantial improvement of current comme
Download or read book Self assembled Quantum Dots in Advanced Structures written by Megan Elizabeth Creasey and published by . This book was released on 2012 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in nanofabrication have bolstered the development of new optical devices with potential uses ranging from conventional optoelectronics, such as lasers and solar cells, to novel devices, like single photon or entangled photon sources. Quantum encryption of optical communications, in particular, requires devices that couple efficiently to an optical fiber and emit, on demand, indistinguishable photons. With these goals in mind, ultrafast spectroscopy is used to study the electron dynamics in epitaxially grown InAs/GaAs quantum dots (QDs). Quantifying the behavior of these systems is critical to the development of more efficient devices. Studies of two newly developed InGaAs QD structures, quantum dot clusters (QDCs) and QDs embedded in photonic wires, are presented herein. GaAs photonic wires with diameters in the range of 200 to 250 nm support only the fundamental HE11 guided mode. To fully quantify these new systems, the emission dynamics of QDs contained within wires in a large range of diameters are studied. Time correlated single photon counting measurements of the ground state exciton lifetimes are in very good agreement with predicted theoretical values for the spontaneous emission rates. For diameters smaller than 200 nm, QD emission into the HE11 mode is strongly inhibited and non-radiative processes dominate the decay rate. The best small diameter wires exhibit inhibition factors as high as 16, on par with the current state of the art for photonic crystals. The QDCs are the product of a hybrid growth technique that combines droplet heteroepitaxy with standard Stranski-Krastanov growth to create many different geometries of QDs. The work presented in this dissertation concentrates specifically on hexa-QDCs consisting of six InAs QDs around a GaAs nanomound. The first ever spectral and temporal properties of QDs within individual hexa-QDCs are presented. The QDs exhibit narrow exciton resonances with good temperature stability, indicating that excitons are well confined within individual QDs. A distinct biexponential decay is observed even at the single QD level. This behavior suggests that non-radiative decay mechanisms and exciton occupation of dark states play a significant role in the recombination dynamics in the QDCs.
Download or read book Compound Semiconductors 1999 written by K Ploog and published by CRC Press. This book was released on 2000-01-01 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: An international perspective on the latest research, Compound Semiconductors 1999 presents an overview of important developments in all III-V compound semiconductors such as GaAs, InP, and GaN; II-VI compounds such as ZnS, ZnSe, and CdTe; IV-IV compounds such as SiC and SiGe; and IV-VI compounds such as PbTe and SnTe. The book emphasizes piezoelectric (or potentially smart) material heterostructures (Ga, Al, In)N, which will influence future research and development funding. As the preeminent forum for research in compound materials and their applications in devices, this essential library reference is invaluable reading for all researchers in semiconductor physics, and electronic and electrical engineering.
Download or read book Electronic Structure and Optical Properties of Self assembled InAs Quantum Dots written by Weidong Yang and published by . This book was released on 1999 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multi Band Effective Mass Approximations written by Matthias Ehrhardt and published by Springer. This book was released on 2014-07-17 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses several mathematical models from the most relevant class of kp-Schrödinger systems. Both mathematical models and state-of-the-art numerical methods for adequately solving the arising systems of differential equations are presented. The operational principle of modern semiconductor nano structures, such as quantum wells, quantum wires or quantum dots, relies on quantum mechanical effects. The goal of numerical simulations using quantum mechanical models in the development of semiconductor nano structures is threefold: First they are needed for a deeper understanding of experimental data and of the operational principle. Secondly, they allow us to predict and optimize in advance the qualitative and quantitative properties of new devices in order to minimize the number of prototypes needed. Semiconductor nano structures are embedded as an active region in semiconductor devices. Thirdly and finally, the results of quantum mechanical simulations of semiconductor nano structures can be used with upscaling methods to deliver parameters needed in semi-classical models for semiconductor devices, such as quantum well lasers. This book covers in detail all these three aspects using a variety of illustrative examples. Readers will gain detailed insights into the status of the multiband effective mass method for semiconductor nano structures. Both users of the kp method as well as advanced researchers who want to advance the kp method further will find helpful information on how to best work with this method and use it as a tool for characterizing the physical properties of semiconductor nano structures. The book is primarily intended for graduate and Ph.D. students in applied mathematics, mathematical physics and theoretical physics, as well as all those working in quantum mechanical research or the semiconductor / opto-electronic industry who are interested in new mathematical aspects.
