Download or read book Cristaux photoniques sur silicium avec des lots quantiques Ge Si et du germanium pur written by Thi-Phuong Ngo and published by . This book was released on 2010 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: Le travail de cette thèse porte sur l'étude des composants photoniques à base d'îlots quantiques Ge/Si et du germanium pur pour la nanophotonique proche infrarouge. La première partie est consacrée à l'étude des cavités à cristaux photoniques en utilisant la photoluminescence des boîtes quantiques Ge/Si auto-assemblées. Les travaux sont centrés sur les nanocavités L3 et H1 réalisées dans les structures photoniques suspendues en silicium. La caractérisation optique par la technique de source interne permet d'obtenir des paramètres associés aux dynamiques de recombinaisons des porteurs de charges dans ces structures. Le facteur de qualité du mode fondamental des cavités n'est limité que par la résolution du spectromètre et non pas par la fabrication. La deuxième partie est consacrée à l'étude des cristaux photoniques réalisés sur substrat de germanium pur sur isolant (GeOI). Le substrat GeOI est constitué d'une couche fine de germanium pur séparée avec son substrat par une couche de silice. Les propriétés optiques sont sondées par la recombinaison radiative de la bande interdite directe du germanium pur à température ambiante. Les résonances des modes optiques sont observées de 1300 nm à 1700 nm dans les nanocavités L3 et H1. Les positions spectrales des résonances peuvent être contrôlées par le pas du réseau et le facteur de remplissage. Proche du bord de bande directe du germanium, le facteur de qualité est limité par l'absorption du matériau. Finalement, le dopage n du germanium obtenu par les techniques de dopage laser et de croissance aux organo-métalliques a été étudié. Ce travail montre que la photoluminescence est fortement exaltée à température ambiante à la fois pour le germanium massif et pour le germanium sur isolant en présence d'un fort dopage n. Les perspectives pour réaliser un laser en germanium dans la filière silicium sont présentées.
Download or read book Composants cristal photonique 2D et 2 5D contenant des bo tes quantiques GeSi sur silicium pour la nanophotonique proche infrarouge written by Xiang Li and published by . This book was released on 2007 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Le travail de cette thèse a été essentiellement consacré à une étude théorique et expérimentale dans le proche infrarouge de nanostructures à cristal photonique constituées par un réseau périodique bidimensionnel de trous d’air dans laquelle est intégrée une source interne réalisée dans la filière silicium. Nous avons pu montrer expérimentalement qu’il était possible de sonder à température ambiante la position spectrale et le profil d’émission des modes de cavité dans la gamme proche infrarouge grâce à la luminescence interne des îlots auto-assemblés Ge/Si. Les analyses effectuées sur les différents mécanismes de pertes ont permis d’identifier la ou les sources de perte dominantes existant dans les cavités à cristal photonique 2D sur silicium et ainsi d’effectuer une ingénierie modale pour obtenir un meilleur confinement optique. En particulier, nous avons montré par micro-photoluminescence qu’il était possible de réaliser des modes de défaut avec un facteur de qualité élevé dans des cavités 2D à cristaux photoniques avec boîtes quantiques GeSi/Si intégrées sur silicium. Parallèlement, nous avons pu mettre en évidence une autre possibilité de contrôler le facteur de qualité pour des modes optiques se situant au centre de la zone de Brillouin par une approche combinant cristal photonique 2D et miroir de Bragg 1D toujours dans la filière silicium. Outre les résultats obtenus sur des mailles carrées, plusieurs voies d’optimisation ont été proposées. L’ensemble des résultats expérimentaux a pu être quantitativement interprété grâce à des simulations numériques de différents types dont principalement la méthode FDTD et la méthode des ondes planes.
Download or read book Etude de composants cristaux photoniques dans la fili re silicium pour les longueurs d ondes des t l communications optiques written by Sylvain David (physicien et auteur d'une thèse en 2003).) and published by . This book was released on 2003 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les cristaux photoniques sont des structures artificielles dont la constante diélectrique est rendue périodique. La propriété essentielle de ces structures est l'ouverture de bandes interdites photoniques pour lesquelles la propagation de la lumière n'est pas autorisée. Une bande interdite complète s'obtient selon certaines conditions portant sur le contraste d'indice, les dimensions et les symétries des réseaux. Ce travail de thèse est essentiellement consacré à l'étude et la réalisation de cristaux photoniques bidimensionnels à base de silicium pour les longueurs d'onde 1,3 - 1,55 [mu]m. Les dispositifs à cristaux photoniques planaires sont confinés par une variation d'indice dans la troisième direction. Deux approches sont envisagées : le fort confinement pour les microcavités et le faible confinement pour l'optique guidée. Nous avons réalisé des microcavités planaires à cristaux photoniques sur substrat SOI (silicium sur isolant) intégrant des boîtes quantiques Ge/Si. Nous avons montré une forte exaltation de la luminescence dans la gamme 1,3 - 1,55[mu]m, caractérisée par un comportement surlinéaire de l'émission. Cette forte augmentation est à la fois le résultat de l'extraction de la lumière par le cristal photonique, mais également la signature d'une forte localisation spatiale des porteurs de charge dans la microcavité. Nous avons également travaillé sur la réalisation de guide d'onde à cristaux photoniques de faible confinement vertical pour le guidage planaire, en utilisant deux technologies : la gravure photo-électrochimique et la gravure plasma ICP (Inductively Coupled Plasma). Nous avons montré la possibilité de réaliser des structures à cristal photonique à travers des guides épais SiGe (2 [mu]m) enterrés dans le silicium. Nous avons également modélisé de nouveaux cristaux photoniques tels que les pavages d'Archimède ou les approximants de quasi-cristaux dans le but d'obtenir le comportement le plus isotrope possible.
Download or read book ICREEC 2019 written by Ahmed Belasri and published by Springer Nature. This book was released on 2020-06-10 with total page 659 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights peer reviewed articles from the 1st International Conference on Renewable Energy and Energy Conversion, ICREEC 2019, held at Oran in Algeria. It presents recent advances, brings together researchers and professionals in the area and presents a platform to exchange ideas and establish opportunities for a sustainable future. Topics covered in this proceedings, but not limited to, are photovoltaic systems, bioenergy, laser and plasma technology, fluid and flow for energy, software for energy and impact of energy on the environment.
Download or read book Molecular Beam Epitaxy written by John Wilfred Orton and published by . This book was released on 2015 with total page 529 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is a history of Molecular Beam Epitaxy (MBE) as applied to the growth of semiconductor thin films (note that it does not cover the subject of metal thin films). It begins by examining the origins of MBE, first of all looking at the nature of molecular beams and considering their application to fundamental physics, to the development of nuclear magnetic resonance and to the invention of the microwave MASER. It shows how molecular beams of silane (SiH4) were used to study the nucleation of silicon films on a silicon substrate and how such studies were extended to compound semiconductors such as GaAs. From such surface studies in ultra-high vacuum the technique developed into a method of growing high quality single crystal films of a wide range of semiconductors. Comparing this with earlier evaporation methods of deposition and with other epitaxial deposition methods such as liquid phase and vapour phase epitaxy (LPE and VPE). The text describes the development of MBE machines from the early 'home-made' variety to that of commercial equipment and show how MBE was gradually refined to produce high quality films with atomic dimensions. This was much aided by the use of various in-situ surface analysis techniques, such as reflection high energy electron diffraction (RHEED) and mass spectrometry, a feature unique to MBE. It looks at various modified versions of the basic MBE process, then proceed to describe their application to the growth of so-called 'low-dimensional structures' (LDS) based on ultra-thin heterostructure films with thickness of order a few molecular monolayers. Further chapters cover the growth of a wide range of different compounds and describe their application to fundamental physics and to the fabrication of electronic and opto-electronic devices. The authors study the historical development of all these aspects and emphasise both the (often unexpected) manner of their discovery and development and the unique features which MBE brings to the growth of extremely complex structures with monolayer accuracy.
Download or read book Organic Solid State Lasers written by Sébastien Forget and published by Springer. This book was released on 2013-07-03 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic lasers are broadly tunable coherent sources, potentially compact, convenient and manufactured at low-costs. Appeared in the mid 60’s as solid-state alternatives for liquid dye lasers, they recently gained a new dimension after the demonstration of organic semiconductor lasers in the 90's. More recently, new perspectives appeared at the nanoscale, with organic polariton and surface plasmon lasers. After a brief reminder to laser physics, a first chapter exposes what makes organic solid-state organic lasers specific. The laser architectures used in organic lasers are then reviewed, with a state-of-the-art review of the performances of devices with regard to output power, threshold, lifetime, beam quality etc. A survey of the recent trends in the field is given, highlighting the latest developments with a special focus on the challenges remaining for achieving direct electrical pumping of organic semiconductor lasers. A last chapter covers the applications of organic solid-state lasers.
Download or read book Diffusion in Materials DIMAT 2011 written by Igor Bezverkhyy and published by Trans Tech Publications Ltd. This book was released on 2012-04-12 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: The International Conference on Diffusion in Materials (DIMAT) is the benchmark conference series for diffusion in solids. DIMAT 2011 was organized by the University of Bourgogne in association with CNRS, Dijon (France). The conference showcased new results concerning theoretical tools as well as applied research approaches. Diffusion processes affect all types of materials: nanomaterials, materials for energy, metallurgy, glasses and ceramics, but each requires its own numerical tools. Volume is indexed by Thomson Reuters CPCI-S (WoS). This volume comprises most of the contributions presented at DIMAT 2011: 4 plenary lectures delivered by famous high-level scientists plus 88 contributions in the form of keynote lectures, talks and posters.
Download or read book Applied Reactor Physics written by Alain Hébert and published by Presses inter Polytechnique. This book was released on 2009 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laser 50 Years Of Discoveries written by Fabien Bretenaker and published by World Scientific. This book was released on 2014-10-27 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique book provides an overview of the principle and applications of lasers enriched with numerous illustrations.Being over fifty years old, lasers continue to amaze us. Their performance characteristics are constantly reaching new limits, and the scope of their applications continues to expand. Yet, it took years of effort by teams of physicists to transform the fundamental notions of Einstein into the first experimental beam of laser light. And history is still going on as fundamental research is now triggered by its remarkable properties.This book addresses every aspects of laser light, from its fundamental principles to its industrial applications, at a level particularly suited for high school teachers, students, and anybody curious about science and technology.
Download or read book Transport Theory written by James J. Duderstadt and published by John Wiley & Sons. This book was released on 1979 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt: Problems after each chapter
Download or read book Physical Properties of Amorphous Materials written by David Adler and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Institute for Amorphous Studies was founded in 1982 as the international center for the investigation of amorphous mate rials. It has since played an important role in promoting the und er standing of disordered matter in general. An Institute lecture series on "Fundamentals of Amorphous Materials and Devices" was held during 1982-83 with distinguished speakers from universities and industry. These events were free and open to the public ,and were attended by many representatives of the scientific community. The lectures themselves were highly successful inasmuch as they provided not only formal instruction but also an opportunity for vigorous and stimulating debate. That last element could not be captured within the pages of a book I but the lectures concentrated on the latest advances in the field I which is why their essential contents are he re reproduced in collective form. Together they constitute an interdisciplinary status report of the field. The speakers brought many different viewpoints and a variety of back ground experiences io bear on the problems involved I but though language and conventions vary I the essential unity of the concerns is very clear I as indeed are the ultimate benefits of the many-sided approach.
Download or read book Nuclear Computational Science written by Yousry Azmy and published by Springer Science & Business Media. This book was released on 2010-04-15 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear engineering has undergone extensive progress over the years. In the past century, colossal developments have been made and with specific reference to the mathematical theory and computational science underlying this discipline, advances in areas such as high-order discretization methods, Krylov Methods and Iteration Acceleration have steadily grown. Nuclear Computational Science: A Century in Review addresses these topics and many more; topics which hold special ties to the first half of the century, and topics focused around the unique combination of nuclear engineering, computational science and mathematical theory. Comprising eight chapters, Nuclear Computational Science: A Century in Review incorporates a number of carefully selected issues representing a variety of problems, providing the reader with a wealth of information in both a clear and concise manner. The comprehensive nature of the coverage and the stature of the contributing authors combine to make this a unique landmark publication. Targeting the medium to advanced level academic, this book will appeal to researchers and students with an interest in the progression of mathematical theory and its application to nuclear computational science.
Download or read book The Physics of Nuclear Reactors written by Serge Marguet and published by Springer. This book was released on 2018-02-26 with total page 1462 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive volume offers readers a progressive and highly detailed introduction to the complex behavior of neutrons in general, and in the context of nuclear power generation. A compendium and handbook for nuclear engineers, a source of teaching material for academic lecturers as well as a graduate text for advanced students and other non-experts wishing to enter this field, it is based on the author’s teaching and research experience and his recognized expertise in nuclear safety. After recapping a number of points in nuclear physics, placing the theoretical notions in their historical context, the book successively reveals the latest quantitative theories concerning: • The slowing-down of neutrons in matter • The charged particles and electromagnetic rays • The calculation scheme, especially the simplification hypothesis • The concept of criticality based on chain reactions • The theory of homogeneous and heterogeneous reactors • The problem of self-shielding • The theory of the nuclear reflector, a subject largely ignored in literature • The computational methods in transport and diffusion theories Complemented by more than 400 bibliographical references, some of which are commented and annotated, and augmented by an appendix on the history of reactor physics at EDF (Electricité De France), this book is the most comprehensive and up-to-date introduction to and reference resource in neutronics and reactor theory.
Download or read book Reactor Dosimetry written by Harry Farrar and published by ASTM International. This book was released on 1994 with total page 854 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the 8th ASTM-Euratom Symposium, held in Vail, Colorado, Aug.-Sept. 1993, to provide a forum for experts to discuss their latest results under the broad theme of dosimetry for the correlation of radiation effects. Preceded by a summary of the keynote presentations and followed by summa
Download or read book Forest Fire Research written by Universidade de Coimbra and published by . This book was released on 2010 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Engineering Handbook written by Kenneth D. Kok and published by CRC Press. This book was released on 2016-10-03 with total page 1328 pages. Available in PDF, EPUB and Kindle. Book excerpt: Building upon the success of the first edition, the Nuclear Engineering Handbook, Second Edition, provides a comprehensive, up-to-date overview of nuclear power engineering. Consisting of chapters written by leading experts, this volume spans a wide range of topics in the areas of nuclear power reactor design and operation, nuclear fuel cycles, and radiation detection. Plant safety issues are addressed, and the economics of nuclear power generation in the 21st century are presented. The Second Edition also includes full coverage of Generation IV reactor designs, and new information on MRS technologies, small modular reactors, and fast reactors.
