Elaboration and characterisation of vitreous thin films doped with semiconductor nanoparticles, anglais

Elaboration and characterisation of vitreous thin films doped with semiconductor nanoparticles, anglais PDF Author: Quang Vinh Lam
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Ce travail concerne la recherche de nouvelles solutions pour l'optique non-linéaire intégrée. Les verres dopés par des nanoparticules semi-conductrices constituent un exemple de matériaux dont les potentialités en optique non-linéaIre sont depuis longtemps reconnues, quoique non encore exploitées. Les effets dus au confinement confèrent aux nanoparticules des propriétés physiques spécifiques par rapport à celles de la phase massive. Le mouvement des porteurs de charge dans une nanoparticule étant limité par le volume, l'énergie cinétique devient discrète et les niveaux s'écartent les uns des autres. C'est cette propriété de discrétisation des niveaux, associée à l'élargIssement du gap semi-conducteur, qui peut être exploitée en optique non-linéaire. Afin de conférer à ces guides d'onde des propriétés optiques non-linéaires, nous avons dopé le sol de TiO2 avec des nanoparticules de CdS ou de PbS produits par la méthode colloïdale des ligands de surface. Nous avons optimisé les paramètres de synthèse de couches minces sol-gel de TiO2 optiquement guidantes, non dopées et dopées avec des nanoparticules de CdS ou de PbS. Les films minces recuits à 100 ou 200°C sont homogènes, exempts de craquelures mais guident la lumière avec une forte atténuation (1 à 1,5 dB/cm). En solution, les nanocristaux produits par une méthode colloïdale présentent une distribution de taille étroite avec un diamètre moyen contrôlé entre 3 et 6 nm. Nous avons observé le ralentissement de leur croissance par la matrice TiO2 et une stabilisation de la solution. L'indice non-linéaire n2 des solutions, mesuré par technique Z-scan, vaut environ -2x10-18 m2/W, valeur comparable à celles reportées dans la littérature. Pour un film TiO2 dopé CdS (30%) et traité à 500°C, l'absorption induite mesurée ([beta] = 16x10-7m/W) est de plusieurs ordres de grandeur supérieure à celle du cristal massif, ce qui est relié aux nombreux niveaux de défauts. Par la technique de pulvérisation radiofréquence, nous avons déposé des nanoparticules d'InSb dans des couches minces de silice et utilisé 2 types de protocole pour leur traitement thermique. Les mesures de non-linéarité on révélé un coefficient d'absorption induite [beta] également bien supérieur à celui d'lnSb massif. On a mis en évidence l'influence du régime continu ou lmpulsionnel des lasers sur les propriétés du matériau.

Elaboration and characterisation of vitreous thin films doped with semiconductor nanoparticles, anglais

Elaboration and characterisation of vitreous thin films doped with semiconductor nanoparticles, anglais PDF Author: Quang Vinh Lam
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

Get Book Here

Book Description
Ce travail concerne la recherche de nouvelles solutions pour l'optique non-linéaire intégrée. Les verres dopés par des nanoparticules semi-conductrices constituent un exemple de matériaux dont les potentialités en optique non-linéaIre sont depuis longtemps reconnues, quoique non encore exploitées. Les effets dus au confinement confèrent aux nanoparticules des propriétés physiques spécifiques par rapport à celles de la phase massive. Le mouvement des porteurs de charge dans une nanoparticule étant limité par le volume, l'énergie cinétique devient discrète et les niveaux s'écartent les uns des autres. C'est cette propriété de discrétisation des niveaux, associée à l'élargIssement du gap semi-conducteur, qui peut être exploitée en optique non-linéaire. Afin de conférer à ces guides d'onde des propriétés optiques non-linéaires, nous avons dopé le sol de TiO2 avec des nanoparticules de CdS ou de PbS produits par la méthode colloïdale des ligands de surface. Nous avons optimisé les paramètres de synthèse de couches minces sol-gel de TiO2 optiquement guidantes, non dopées et dopées avec des nanoparticules de CdS ou de PbS. Les films minces recuits à 100 ou 200°C sont homogènes, exempts de craquelures mais guident la lumière avec une forte atténuation (1 à 1,5 dB/cm). En solution, les nanocristaux produits par une méthode colloïdale présentent une distribution de taille étroite avec un diamètre moyen contrôlé entre 3 et 6 nm. Nous avons observé le ralentissement de leur croissance par la matrice TiO2 et une stabilisation de la solution. L'indice non-linéaire n2 des solutions, mesuré par technique Z-scan, vaut environ -2x10-18 m2/W, valeur comparable à celles reportées dans la littérature. Pour un film TiO2 dopé CdS (30%) et traité à 500°C, l'absorption induite mesurée ([beta] = 16x10-7m/W) est de plusieurs ordres de grandeur supérieure à celle du cristal massif, ce qui est relié aux nombreux niveaux de défauts. Par la technique de pulvérisation radiofréquence, nous avons déposé des nanoparticules d'InSb dans des couches minces de silice et utilisé 2 types de protocole pour leur traitement thermique. Les mesures de non-linéarité on révélé un coefficient d'absorption induite [beta] également bien supérieur à celui d'lnSb massif. On a mis en évidence l'influence du régime continu ou lmpulsionnel des lasers sur les propriétés du matériau.

Synthesis and Characterisation of Semiconductor Nanoparticle Thin Films

Synthesis and Characterisation of Semiconductor Nanoparticle Thin Films PDF Author: David Cant
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The Materials Science of Thin Films

The Materials Science of Thin Films PDF Author: Milton Ohring
Publisher: Academic Press
ISBN: 9780125249904
Category : Science
Languages : en
Pages : 744

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Book Description
Prepared as a textbook complete with problems after each chapter, specifically intended for classroom use in universities.

Photovoltaic and Photoactive Materials

Photovoltaic and Photoactive Materials PDF Author: Joseph M. Marshall
Publisher: Springer Science & Business Media
ISBN: 9401006326
Category : Technology & Engineering
Languages : en
Pages : 361

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Book Description
The primary objective of this NATO Advanced Study Institute (ASI) was to present an up-to-date overview of various current areas of interest in the field of photovoltaic and related photoactive materials. This is a wide-ranging subject area, of significant commercial and environmental interest, and involves major contributions from the disciplines of physics, chemistry, materials, electrical and instrumentation engineering, commercial realisation etc. Therefore, we sought to adopt an inter disciplinary approach, bringing together recognised experts in the various fields while retaining a level of treatment accessible to those active in specific individual areas of research and development. The lecture programme commenced with overviews of the present relevance and historical development of the subject area, plus an introduction to various underlying physical principles of importance to the materials and devices to be addressed in later lectures. Building upon this, the ASI then progressed to more detailed aspects of the subject area. We were also fortunately able to obtain a contribution from Thierry Langlois d'Estaintot of the European Commission Directorate, describing present and future EC support for activities in this field. In addition, poster sessions were held throughout the meeting, to allow participants to present and discuss their current activities. These were supported by what proved to be very effective feedback sessions (special thanks to Martin Stutzmann), prior to which groups of participants enthusiastically met (often in the bar) to identify and agree topics of common interest.

Metal Nanoparticles

Metal Nanoparticles PDF Author: Daniel L. Fedlheim
Publisher: CRC Press
ISBN: 9780585404394
Category : Science
Languages : en
Pages : 348

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Book Description
A state-of-the-art reference, Metal Nanoparticles offers the latest research on the synthesis, characterization, and applications of nanoparticles. Following an introduction of structural, optical, electronic, and electrochemical properties of nanoparticles, the book elaborates on nanoclusters, hyper-Raleigh scattering, nanoarrays, and several applications including single electron devices, chemical sensors, biomolecule sensors, and DNA detection. The text emphasizes how size, shape, and surface chemistry affect particle performance throughout. Topics include synthesis and formation of nanoclusters, nanosphere lithography, modeling of nanoparticle optical properties, and biomolecule sensors.

Transmission Electron Microscopy

Transmission Electron Microscopy PDF Author: C. Barry Carter
Publisher: Springer
ISBN: 3319266519
Category : Technology & Engineering
Languages : en
Pages : 543

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Book Description
This text is a companion volume to Transmission Electron Microscopy: A Textbook for Materials Science by Williams and Carter. The aim is to extend the discussion of certain topics that are either rapidly changing at this time or that would benefit from more detailed discussion than space allowed in the primary text. World-renowned researchers have contributed chapters in their area of expertise, and the editors have carefully prepared these chapters to provide a uniform tone and treatment for this exciting material. The book features an unparalleled collection of color figures showcasing the quality and variety of chemical data that can be obtained from today’s instruments, as well as key pitfalls to avoid. As with the previous TEM text, each chapter contains two sets of questions, one for self assessment and a second more suitable for homework assignments. Throughout the book, the style follows that of Williams & Carter even when the subject matter becomes challenging—the aim is always to make the topic understandable by first-year graduate students and others who are working in the field of Materials Science Topics covered include sources, in-situ experiments, electron diffraction, Digital Micrograph, waves and holography, focal-series reconstruction and direct methods, STEM and tomography, energy-filtered TEM (EFTEM) imaging, and spectrum imaging. The range and depth of material makes this companion volume essential reading for the budding microscopist and a key reference for practicing researchers using these and related techniques.

Sol-Gel Technologies for Glass Producers and Users

Sol-Gel Technologies for Glass Producers and Users PDF Author: Michel Andre Aegerter
Publisher: Springer Science & Business Media
ISBN: 0387889531
Category : Technology & Engineering
Languages : en
Pages : 474

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Book Description
Sol-Gel Techniques for Glass Producers and Users provides technological information, descriptions and characterizations of prototypes, or products already on the market, and illustrates advantages and disadvantages of the sol-gel process in comparison to other methods. The first chapter entitled "Wet Chemical Technology" gives a summary of the basic principles of the sol-gel chemistry. The most promising applications are related to coatings. Chapter 2 describes the various "Wet Chemical Coating Technologies" from glass cleaning to many deposition and post-coating treatment techniques. These include patterning of coatings through direct or indirect techniques which have became very important and for which the sol-gel processing is particularly well adapted. Chapter 3 entitled "Bulk Glass Technologies" reports on the preparation of special glasses for different applications. Chapter 4 entitled "Coatings and Materials Properties" describes the properties of the different coatings and the sol-gel materials, fibers and powders. The chapter also includes a section dedicated to the characterization techniques especially applied to sol-gel coatings and products.

Thin Film Phenomena

Thin Film Phenomena PDF Author: Kasturi L. Chopra
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 872

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Nanotechnology in Construction

Nanotechnology in Construction PDF Author: Peter J M Bartos
Publisher: Royal Society of Chemistry
ISBN: 1847551521
Category : Technology & Engineering
Languages : en
Pages : 397

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Book Description
The importance of nanotechnology related research and development has become recognised worldwide. Substantial public and private investment is now being ploughed into research and development in a number of industrial sectors, where nanotechnology has become established and has led to new commercial products. The construction industry, having major economic significance with nano-scale research and development which is only emerging, offers a wide scope for exploitation of nanotechnology. With international contributions from experts in the field, Nanotechnology in Construction amalgamates previously fragmented research and emerging trends. It reflects the inherent multi-disciplinary nature of nano-scale research in construction and contributions cover a wide spectrum, from highly scientific investigations to futuristic applications. The book is organised into four broad sections, the first reviews and analyses the prospects of exploitation of nanotechnology in construction, the second discusses novel tools and their capabilities, the final two sections show existing significant products where nanotechnology has been already been exploited or where product development is under-way. Nanotechnology in Construction will appeal to researchers already working in this field as well as those wishing to enter it. It will also inform governmental and other funding agencies of the most promising future directions and their related timescales. Practical applications are considered and explanations of the underlying basics are given, raising awareness and understanding of what nanotechnology can offer to construction professionals in general.

Phosphor Handbook

Phosphor Handbook PDF Author: Shigeo Shionoya
Publisher: CRC Press
ISBN: 1420005235
Category : Technology & Engineering
Languages : en
Pages : 1078

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Book Description
A benchmark publication, the first edition of the Phosphor Handbook set the standard for references in this field. Completely revised and updated, this second edition explores new and emerging fields such as nanophosphors, nanomaterials, UV phosphors, quantum cutters, plasma display phosphors, sol-gel and other wet phosphor preparation techniques, preparation through combustion, bioluminescence phosphors and devices, and new laser materials such as OLED. It also contains new chapters on the applications of phosphors in solid state lighting, photoionization of luminescent centers in insulating phosphors, and recent developments in halide-based scintillators. The handbook provides a comprehensive description of phosphors with an emphasis on practical phosphors and their uses in various kinds of technological applications. It covers the fundamentals, namely the basic principles of luminescence, the principle phosphor materials, and their optical properties. The authors describe phosphors used in lamps, cathode-ray tubes, x-ray, and ionizing radiation detection. They cover common measurement methodology used to characterize phosphor properties, discuss a number of related items, and conclude with the history of phosphor technology and industry.