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Optimisation De Lepitaxie Sous Jets Moleculaires Dheterostructures A Base De Gan
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Book Synopsis EPITAXIE PAR JETS MOLECULAIRES DE GAN, ALN, INN ET LEURS ALLIAGES by : FREDERIC.. WIDMANN
Download or read book EPITAXIE PAR JETS MOLECULAIRES DE GAN, ALN, INN ET LEURS ALLIAGES written by FREDERIC.. WIDMANN and published by . This book was released on 1998 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: CE TRAVAIL A PORTE SUR LA CROISSANCE EPITAXIALE DES NITRURES D'ELEMENTS III GAN, ALN, ET INN, EN UTILISANT L'EPITAXIE PAR JETS MOLECULAIRES ASSISTEE PAR PLASMA D'AZOTE. NOUS AVONS OPTIMISE LES PREMIERS STADES DE LA CROISSANCE DE GAN OU ALN SUR SUBSTRAT AL#2O#3 (0001). LE PROCESSUS UTILISE CONSISTE A NITRURER LA SURFACE DU SUBSTRAT A L'AIDE DU PLASMA D'AZOTE, AFIN DE LA TRANSFORMER EN ALN, PUIS A FAIRE CROITRE UNE COUCHE TAMPON D'ALN OU DE GAN A BASSE TEMPERATURE, AVANT DE REPRENDRE LA CROISSANCE DE GAN OU ALN A HAUTE TEMPERATURE (680 A 750C). NOUS AVONS EN PARTICULIER ETUDIE LES PROPRIETES D'UNE COUCHE DE GAN EN FONCTION DE LA TEMPERATURE A LAQUELLE EST REALISEE L'ETAPE DE NITRURATION. LORSQUE LES CONDITIONS DE DEMARRAGE DE LA CROISSANCE SONT OPTIMISEES, NOUS AVONS PU OBSERVER DES OSCILLATIONS DE RHEED PENDANT LA CROISSANCE DE LA COUCHE DE GAN. NOUS AVONS ETUDIE L'EFFET DU RAPPORT V/III SUR LA MORPHOLOGIE DE SURFACE ET LES PROPRIETES OPTIQUES ET STRUCTURALES DE CETTE COUCHE. NOUS AVONS PROPOSE L'UTILISATION DE L'INDIUM EN TANT QUE SURFACTANT POUR AMELIORER CES PROPRIETES. NOUS AVONS ENSUITE ABORDE LA REALISATION DE SUPERRESEAUX GAN/ALN DONT NOUS AVONS OPTIMISE LES INTERFACES. LES MECANISMES DE RELAXATION DES CONTRAINTES DE ALN SUR GAN ET GAN SUR ALN ONT ETE ETUDIES. NOUS AVONS EGALEMENT ELABORE LES ALLIAGES ALGAN ET INGAN, COMME BARRIERES QUANTIQUES DANS LES HETEROSTRUCTURES. NOUS AVONS MONTRE QUE LA RELAXATION ELASTIQUE DES CONTRAINTES DE GAN EN EPITAXIE SUR ALN DONNE LIEU A LA FORMATION D'ILOTS DE TAILLES NANOMETRIQUES, QUI SE COMPORTENT COMME DES BOITES QUANTIQUES. LEUR DENSITE ET LEUR TAILLE DEPENDENT DE LA TEMPERATURE DE CROISSANCE, ET DES CONDITIONS DE MURISSEMENT APRES CROISSANCE. LES PROPRIETES OPTIQUES DE CES ILOTS SONT GOUVERNEES A LA FOIS PAR LES EFFETS DE CONFINEMENT QUANTIQUE ET PAR LE FORT CHAMP PIEZO-ELECTRIQUE INDUIT PAR LA CONTRAINTE DANS LES ILOTS.
Book Synopsis Croissance par épitaxie par jets moléculaires et propriétés optiques d'hétérostructures à base de CdHgTe by : Laurent Ulmer
Download or read book Croissance par épitaxie par jets moléculaires et propriétés optiques d'hétérostructures à base de CdHgTe written by Laurent Ulmer and published by . This book was released on 1992 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: CE TRAVAIL A ETE CONSACRE A L'ELABORATION PAR EPITAXIE PAR JETS MOLECULAIRES D'HETEROSTRUCTURES A BASE DE CD#XHG#1##XTE (0.5X
Book Synopsis Growth and Strain Relaxation Mechanisms of Group III Nitride Heterostructures by : Hans Christoph Adelmann
Download or read book Growth and Strain Relaxation Mechanisms of Group III Nitride Heterostructures written by Hans Christoph Adelmann and published by . This book was released on 2002 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ce travail a porté sur les mécanismes de croissance épitaxiale et de relaxation de contrainte d'hétérostructures de nitrures d'éléments III, GaN et AIN, en épitaxie par jets moléculaires assistée par plasma d'azote. Nous avons étudié les structures de la surface (0001) de GaN et d'AIN en conditions d'excès de métal. Nous avons montré que la quantité de Ga absorbée sur GaN peur être évaluée par RHEED. Cette méthode a été appliquée à l'absorption de Ga et à la croissance de GaN en conditions riche Ga. Dans les deux cas, les résultats ont permis de tracer un diagramme qui décrit la quantité de Ga présente sur GaN en fonction du flux de Ga et de la température de croissance. Les morphologies de surface obtenues après la croissance de GaN dans les différentes parties du diagramme sont discutées. Nous avons ensuite abordé la relaxation des contraintes d'hétérostructures GaN/AIN. En conditions d'excès d'azote, la relaxation se produit de façon élastique, soit par la formation d'îlots plats à basse température, soit par la formation d'îlots pyramidaux selon le mode Stranski-Krastanow à haute température. En conditions d'excès de métal, la croissance est bidimensionnelle et la relaxation se produit par introduction de dislocations. Nous avons démontré que l'épaisseur critique de cette relaxation plastique dépend fortement des conditions de croissance. L'étude de la nucléation d'îlots de GaN sur AIN en mode Stranski-Krastanowa permis de contrôler leur taille et leur densité. Ces deux paramètres peuvent être variés de façon indépendante dans une large gamme de valeurs. Nous avons trouvé que l'optimisation de la distribution de taille des îlots est compliquée par une distribution bimodale à haute température. Finalement, nous avons étudié l'adsorption de Ga sur les surfaces (0001) d'AIN et d'AlGaN. Ceci a permis de démontrer la faisabilité d'épitaxie en flux alternés de GaN sur AIN et AlGaN.
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.
Book Synopsis Molecular Beam Epitaxy by : John Wilfred Orton
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 ZnO Thin Films written by Paolo Mele and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide (ZnO) is an n-type semiconductor with versatile applications such as optical devices in ultraviolet region, piezoelectric transducers, transparent electrode for solar cells and gas sensors. This book "ZnO Thin Films: Properties, Performance and Applications" gives a deep insight in the intriguing science of zinc oxide thin films. It is devoted to cover the most recent advances and reviews the state of the art of ZnO thin films applications involving energy harvesting, microelectronics, magnetic devices, photocatalysis, photovoltaics, optics, thermoelectricity, piezoelectricity, electrochemistry, temperature sensing. It serves as a fundamental information source on the techniques and methodologies involved in zinc oxide thin films growth, characterization, post-deposition plasma treatments and device processing. This book will be invaluable to the experts to consolidate their knowledge and provide insight and inspiration to beginners wishing to learn about zinc oxide thin films.
Book Synopsis Physical Properties of Amorphous Materials by : David Adler
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.
Book Synopsis Forest Fire Research by : Universidade de Coimbra
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:
