Download or read book Epitaxial Growth and Real Time Characterization of Self assembled Quantum Dots Using Reflection High Energy Electron Diffraction written by Chandani P.K. Rajapaksha and published by . This book was released on 2010 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Epitaxial Growth and Real time Electron Diffraction Analysis of Advanced III V Semiconductor based Quantum Dots written by Manori Vajira Chintha Gunasekera and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The impact of growth kinetics on structural properties significantly affects optical and electronic performances of self-assembled Stranski-Krastanov (SK) quantum dots. Here and within the framework of the synthesis of archetype InAs/GaAs quantum dot system we have undertaken a systematic study on the evolution of dot facet orientation in terms diffraction characterization by the reflection high-energy electron diffraction (RHEED) technique. The existence of a sharp transition of facet arrangements and shapes near the onset of dot formation is investigated, and a dot structure bound by {2 5 11} facets is proposed. During further calculations, we observed asymmetric ripening of quantum dot facets at initial growth stages, and as the dot ripens, more symmetric facet arrangement to the incident direction was noted. Further, incorporating the correlation between dot structural properties and RHEED intensity features, we propose structures for quantum dots bounded by {1 3 6} and {1 (3 ) ̅5} facets for both asymmetric and symmetric situations. In addition, development of advanced quantum dot structures to fabricate wetting layer separated InAs quantum dots is implemented. Improvement of photoluminescence emission from InAs quantum dots embedded in a GaAs matrix is presented at the end of the work.
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 Lateral Alignment of Epitaxial Quantum Dots written by Oliver G. Schmidt and published by Springer Science & Business Media. This book was released on 2007-08-17 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the full range of possible strategies for laterally aligning self-assembled quantum dots on a substrate surface, beginning with pure self-ordering mechanisms and culminating with forced alignment by lithographic positioning. The text addresses both short- and long-range ordering phenomena and introduces future high integration of single quantum dot devices on a single chip. Contributions by well-known experts ensure that all relevant quantum-dot heterostructures are elucidated from diverse perspectives.
Download or read book Comprehensive Semiconductor Science and Technology written by and published by Newnes. This book was released on 2011-01-28 with total page 3572 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductors are at the heart of modern living. Almost everything we do, be it work, travel, communication, or entertainment, all depend on some feature of semiconductor technology. Comprehensive Semiconductor Science and Technology, Six Volume Set captures the breadth of this important field, and presents it in a single source to the large audience who study, make, and exploit semiconductors. Previous attempts at this achievement have been abbreviated, and have omitted important topics. Written and Edited by a truly international team of experts, this work delivers an objective yet cohesive global review of the semiconductor world. The work is divided into three sections. The first section is concerned with the fundamental physics of semiconductors, showing how the electronic features and the lattice dynamics change drastically when systems vary from bulk to a low-dimensional structure and further to a nanometer size. Throughout this section there is an emphasis on the full understanding of the underlying physics. The second section deals largely with the transformation of the conceptual framework of solid state physics into devices and systems which require the growth of extremely high purity, nearly defect-free bulk and epitaxial materials. The last section is devoted to exploitation of the knowledge described in the previous sections to highlight the spectrum of devices we see all around us. Provides a comprehensive global picture of the semiconductor world Each of the work's three sections presents a complete description of one aspect of the whole Written and Edited by a truly international team of experts
Download or read book Ceramic Abstracts written by American Ceramic Society and published by . This book was released on 1995 with total page 1150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics of Quantum Rings written by Vladimir M. Fomin and published by Springer Science & Business Media. This book was released on 2013-08-29 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals with a new class of materials, quantum rings. Innovative recent advances in experimental and theoretical physics of quantum rings are based on the most advanced state-of-the-art fabrication and characterization techniques as well as theoretical methods. The experimental efforts allow to obtain a new class of semiconductor quantum rings formed by capping self-organized quantum dots grown by molecular beam epitaxy. Novel optical and magnetic properties of quantum rings are associated with non-trivial topologies at the nanoscale. An adequate characterization of quantum rings is possible on the basis of modern characterization methods of nanostructures, such as Scanning Tunneling Microscopy. A high level of complexity is demonstrated to be needed for a dedicated theoretical model to adequately represent the specific features of quantum rings. The findings presented in this book contribute to develop low-cost high-performance electronic, spintronic, optoelectronic and information processing devices based on quantum rings.
Download or read book An Innovative Epitaxial Growth Method for Minimizing Dislocations in Thin film Quantum dot Optoelectronic and Photovoltaic Device Applications written by Jateen S. Gandhi and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A new buffer layer method for epitaxial growth of lattice-mismatched semiconductor quantum-dots based p-i-n structures is presented. To our knowledge this is the first instance of a dislocation-reduction approach that has shown reduced dark current behavior in a quantumdot device compared to its counterpart homojunction p-n device consisted of the barrier material. The present work compared a lattice misfit strain build-up behavior between an In0.15Ga0.85As (p) / InAs (i) / In0.15Ga0.85As (n) (QD) device to an In0.15Ga0.85As (p) / In0.15Ga0.85As (n) (HOM) device, as both were grown on an un-doped gallium arsenide (GaAs) (100) substrate. The intrinsic region of QD device incorporated 5 layers of 2.1 ML indium arsenide quantum dots that were fabricated using self-assembly via Stranski-Krastanov strain release mechanism. Atomic force microscopy measurements exhibited 35 ± 3 nm sized pyramidal islands with a narrow distribution and a density of 2.5 x 1010 per cm2. A low temperature (6K) photoluminescence characterization of the QD sample revealed an activity at 1400 nm wavelength that was attributed to optical pumping of carriers, which experienced a 3-dimensional quantum confinement due to a potential well formed by In0.15Ga0.85As matrix, and their subsequent radiative recombination. Both of the QD and HOM samples were characterized using x-ray diffractometer (XRD) and a high resolution transmission electron microscopy (HRTEM) method. The XRD data recorded a signature of the biaxially strained pseudomorphic section of In0.15Ga0.85As buffer layer that absorbed a lattice misfit due to epitaxial growth on GaAs substrate. This signature consisted of a set of twin peaks at higher and lower 20 degrees resembling elastically strained and plastically relaxed sections, respectively, of the buffer layer residing in the vicinity of buffer-GaAs interface. A comparison of those peaks between QD and HOM samples exhibited an increase in the volume of the plastically relaxed region in HOM sample and a cross-sectional HRTEM image revealed absence of dislocations within the intrinsic region of QD sample. A current-voltage characterization using a four-probe tool recorded lower dark current from the QD device compared to HOM that, along with XRD and HRTEM results, confirmed an enhanced elastic absorption of the lattice misfit in the QD device. The buffer layer method is advantageous in the field of epitaxial growth due to the virtues of simplicity, efficient device fabrication, improved thermal stress performance and easier strain build-up management.
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 Epitaxial Growth Part A written by J Matthews and published by Elsevier. This book was released on 2012-12-02 with total page 401 pages. Available in PDF, EPUB and Kindle. Book excerpt: Epitaxial Growth, Part A is a compilation of review articles that describe various aspects of the growth of single-crystal films on single-crystal substrates. The collection contains topics on the historical development of epitaxy, the nucleation of thin films, the structure of the interface between film and substrate, and the generation of defects during film growth. The text also provides descriptions of the methods used to prepare and examine thin films and a list of the overgrowth-substrate combinations studied. Mineralogists, materials engineers and scientists, and physicists will find this book a great source of insight.
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 Growth and Characterization of Self assembled Quantum Dots for Intermediate Band Solar Cells written by Meng Sun and published by . This book was released on 2013 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, Molecular Beam Epitaxy technology is presented in detail and several powerful characterization techniques such as XRD, AFM, TEM, PL are also reviewed. SAQDs are discussed to be applied in IBSCs application due to the formation of intermediate band which helps to absorb sub-band gap photons. We investigate how the structural and optical properties of InAs self-assembled quantum dots buried in AlAs0.56Sb0.44 barriers can be controlled through the use of thin GaAs1xSbx cladding layers. Structural and optical properties of the SAQDs are studied, and the characteristics we demonstrate for this quantum dot system show great potential for application in intermediate band solar cells.
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 Epitaxial Growth Principles and Applications Volume 570 written by Albert-László Barabási and published by . This book was released on 1999-08-26 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: The MRS Symposium Proceeding series is an internationally recognised reference suitable for researchers and practitioners.
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 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 Proclamatie van de Provisioneele Representanten des Volks van het Ambacht van Nieuwer Amstel 14 Juni 1795 written by and published by . This book was released on 1795 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
