Download or read book Contribution la mod lisation th orique et l tude du transport quantique dans les dispositifs base de nanotubes de carbone written by Rémi Avriller and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les nanotubes de carbone sont des structures tubulaires obtenues en enroulant une feuille de graphène sur elle-même. La manière d'effectuer cette enroulement détermine la chiralité du tube, ainsi que l'ensemble de ses propriétés électroniques et vibrationnelles. Du fait de la nature ondulatoire de l'électron et de la faible dimensionnalité des nanotubes de carbone, cette structure de bandes est fortement modulée par l'application d'un champ magnétique externe. La présence d'un potentiel de désordre(rupture de l'invariance par translation) ou l'excitation d'un mécanisme d'interaction entre électrons et modes phonons optiques ont aussi des conséquences importantes sur cette structure électronique. L'objectif de cette thèse est de s'intéresser aux propriétés de transport quantique des nanotubes de carbone, propriétés déterminées par la compétition entre interférences quantiques, structure de bandes et mécanismes d'interaction. Pour ce faire, une étude détaillée des nanotubes de carbone désordonnés, dopés à l'azote ou au bore sera menée, étude permettant de modéliser de manière fine le hamiltonien de désordre ainsi que de sonder les lois d'échelles de la conductance. La présence d'un champ magnétique statique et uniforme sera considérée, ainsi que ses conséquences sur les régimes de transport à faible tension de polarisation(formation d'un niveau de Landau et oscillation Aharonov-Bohm). Finalement, nous nous intéresserons au rôle des collisions inélastiques entre électrons et phonons optiques de haute symétrie, sur les propriétés de transport quantique(rôle priviligié lorsque la tension de polarisation franchit un seuil d'excitation inélastique). Du fait de la faible dimensionnalité, l'approximation adiabatique n'est plus valide, et un traitement cohérent dans l'espace de Fock électron-phonon doit être mené. Pour chacune de ces études, un modèle hamiltonien effectif est construit et le problème du transport quantique résolu analytiquement ou numériquement.

Download or read book Contribution la mod lisation th orique et l tude du transport quantique dans les dispositifs base de nanotubes de carbone written by Rémi Avriller and published by . This book was released on 2008 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les nanotubes de carbone sont des structures tubulaires obtenues en enroulant une feuille de graphène sur elle-même. La manière d'effectuer cette enroulement détermine la chiralité du tube, ainsi que l'ensemble de ses propriétés électroniques et vibrationnelles. Du fait de la nature ondulatoire de l'électron et de la faible dimensionnalité des nanotubes de carbone, cette structure de bandes est fortement modulée par l'application d'un champ magnétique externe. La présence d'un potentiel de désordre(rupture de l'invariance par translation) ou l'excitation d'un mécanisme d'interaction entre électrons et modes phonons optiques ont aussi des conséquences importantes sur cette structure électronique. L'objectif de cette thèse est de s'intéresser aux propriétés de transport quantique des nanotubes de carbone, propriétés déterminées par la compétition entre interférences quantiques, structure de bandes et mécanismes d'interaction. Pour ce faire, une étude détaillée des nanotubes de carbone désordonnés, dopés à l'azote ou au bore sera menée, étude permettant de modéliser de manière fine le hamiltonien de désordre ainsi que de sonder les lois d'échelles de la conductance. La présence d'un champ magnétique statique et uniforme sera considérée, ainsi que ses conséquences sur les régimes de transport à faible tension de polarisation(formation d'un niveau de Landau et oscillation Aharonov-Bohm). Finalement, nous nous intéresserons au rôle des collisions inélastiques entre électrons et phonons optiques de haute symétrie, sur les propriétés de transport quantique(rôle priviligié lorsque la tension de polarisation franchit un seuil d'excitation inélastique). Du fait de la faible dimensionnalité, l'approximation adiabatique n'est plus valide, et un traitement cohérent dans l'espace de Fock électron-phonon doit être mené. Pour chacune de ces études, un modèle hamiltonien effectif est construit et le problème du transport quantique résolu analytiquement ou numériquement.

Download or read book Carbon Nanotubes and Graphene for Photonic Applications written by Shinji Yamashita and published by Elsevier. This book was released on 2013-08-31 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: The optical properties of carbon nanotubes and graphene make them potentially suitable for a variety of photonic applications. Carbon nanotubes and graphene for photonic applications explores the properties of these exciting materials and their use across a variety of applications.Part one introduces the fundamental optical properties of carbon nanotubes and graphene before exploring how carbon nanotubes and graphene are synthesised. A further chapter focusses on nonlinearity enhancement and novel preparation approaches for carbon nanotube and graphene photonic devices. Chapters in part two discuss carbon nanotubes and graphene for laser applications and highlight optical gain and lasing in carbon nanotubes, carbon nanotube and graphene-based fiber lasers, carbon-nanotube-based bulk solid-state lasers, electromagnetic nonlinearities in graphene, and carbon nanotube-based nonlinear photonic devices. Finally, part three focusses on carbon-based optoelectronics and includes chapters on carbon nanotube solar cells, a carbon nanotube-based optical platform for biomolecular detection, hybrid carbon nanotube-liquid crystal nanophotonic devices, and quantum light sources based on individual carbon nanotubes.Carbon nanotubes and graphene for photonic applications is a technical resource for materials scientists, electrical engineers working in the photonics and optoelectronics industry and academics and researchers interested in the field. - Covers the properties and fabrication of carbon nanotubes and graphene for photonic applications - Considers the uses of carbon nanotubes and graphene for laser applications - Explores numerous carbon-based light emitters and detectors

Download or read book Conduction in Carbon Nanotube Networks written by Robert A. Bell and published by Springer. This book was released on 2016-10-17 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis exploits the ability of the linear-scaling quantum mechanical code ONETEP to analyze systems containing many thousands of atoms. By implementing an electron transport capability to the code, it also investigates a range of phenomena associated with electrical conduction by nanotubes and, in particular, the process of transport electrons between tubes. Extensive work has been done on the conductivity of single carbon nanotubes. However, any realistic wire made of nanotubes will consist of a large number of tubes of finite length. The conductance of the resulting wire is expected to be limited by the process of transferring electrons from one tube to another.These quantum mechanical calculations on very large systems have revealed a number of incorrect claims made previously in the literature. Conduction processes that have never before been studied at this level of theory are also investigated.

Download or read book Graphene and Carbon Nanotubes written by Ermin Malic and published by John Wiley & Sons. This book was released on 2013-04-12 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: A first on ultrafast phenomena in carbon nanostructures like graphene, the most promising candidate for revolutionizing information technology and communication The book introduces the reader into the ultrafast nanoworld of graphene and carbon nanotubes, including their microscopic tracks and unique optical finger prints. The author reviews the recent progress in this field by combining theoretical and experimental achievements. He offers a clear theoretical foundation by presenting transparently derived equations. Recent experimental breakthroughs are reviewed. By combining both theory and experiment as well as main results and detailed theoretical derivations, the book turns into an inevitable source for a wider audience from graduate students to researchers in physics, materials science, and electrical engineering who work on optoelectronic devices, renewable energies, or in the semiconductor industry.

Download or read book Superconductivity in Graphene and Carbon Nanotubes written by Pablo Burset Atienza and published by . This book was released on 2013-10-31 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dispositifs Hybrides Base de Carbone written by Yani Chen and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the frame of the intense research on electronics beyond CMOS, molecular electronics offers the versatility of organic chemistry in order to tailor new functions combining optical and electronic specifications, while accessing the quantum confined regime intrinsic to small molecules. As 1D conductors, carbon nanotubes bridge the gap between small molecules electronics and semiconductor technology with great promises while being a playground for organic chemistry. Beyond miniaturization, they offer the opportunity to design new devices from accurate sensors to optoelectronic and quantum devices. However most studies focus on sensor or photovoltaic applications and thus involve a macroscopic assembly of nanotubes. This averages the excitation transfers, which prevents access to their fundamental mechanisms. This requires the design of individual carbon nanotube based functional devices. For this issue double wall carbon nanotubes have many advantages over simple SWNTs. In general, they exhibit higher stability, which can be a substantial help in high-current and high-field experiments. They realize a core-shell system: their concentric structure suggests its use for independent doping or functionalization of inner and outer tubes.In this PhD project, we demonstrate field effect transistors based on hybrid systems of individual double wall carbon nanotubes and optically sensitive molecule.We first introduce the method for making individual double wall carbon nanotube field effect transistors (DWNT FETs), which are then characterized both optically and electrically. We also studied the electron phonon coupling in the DWNT system by Raman spectroscopy with electrostatic gating. The inner metallic tube is also affected by the electrostatic gate and shows dramatic changes of the overall Raman signature.We then functionalized non covalently two kinds of optically sensitive molecules to DWNT and graphene FETs (Terpyridine Osmium complex and Zinc(II) metalloporphyrin). The hybrids are characterized both optically and electrically. Charge transfer between DWNTs and molecules plays as a chemical gating which can be detected by Raman spectroscopy as well as electrical transport measurements, which indicates that the DWNT FETs can be utilized for molecular sensing. Light excitation of the molecules leads to doping of the hybrids and reveals the coupling between the nanotube walls.Moreover, we realized wavelength dependent optical gating on the hybrid device, detected by both Raman spectroscopy and electrical transport measurements at both room temperature and helium temperature. The optical control of the hybrids' electronic behavior will be elucidated in terms of photo-induced charge transfer between the grafted molecules and the DWNT component. As a consequence, this hybrid FETs can be used as an optically controlled memory down to single electron transfers at low temperature.

Download or read book Electronic Transport in Quantum Confined Systems written by Maxime Berthe and published by . This book was released on 2007 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: Depuis l'avènement des nanotechnologies, une grande quantité de matériaux sont façonnés à l'échelle du nanomètre par des techniques diverses et l'intégration de ces nanostructures demande une caractérisation de leur structure électronique. La microscopie à effet tunnel est adaptée à ces études car elle permet l'adressage de nanostructures uniques pour mesurer leur structure électronique. Nous rapportons ici l'étude du transport électronique dans deux types de nanostructures: des nanotubes de carbone simple paroi déposés sur une surface d'or et des atomes uniques de silicium sur un substrat de silicium. Dans la première étude, le couplage faible entre un nanotube et le substrat permet d'accéder à la densité d'états unidimensionnelle des nanotubes et autorise la formation de défauts ponctuels, ayant des états localisés dans la bande interdite des nanotubes. Cette modification, réversible, de la structure atomique des nanotubes de carbone amène des opportunités concernant la modification controlée et à volonté de leurs propriétés électroniques. La deuxième étude vise à caractériser la dynamique des porteurs dans une liaison pendante de silicium énergétiquement isolée de tout autre état électronique sur une surface Si(111). L'analyse du transport révèle un courant inélastique mettant en oeuvre la recombinaison non radiative des électrons de la pointe avec des trous capturés par l'état de la liaison pendante, grâce à l'émission de vibrations. La spectroscopie à effet tunnel montre de plus que l'on peut caractériser l'efficacité de capture d'un état quantique unique, en connaissant son niveau d'énergie, sa fonction d'onde, sa section de capture et le couplage électron-phonon.

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 Magnetism and Superconductivity written by Laurent-Patrick Levy and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: This up-to-date work presents a modern vision of magnetism and superconductivity covering both microscopic and phenomenological aspects. The basic information is illustrated with the help of current research topics such as the quantum Hall effect or mesoscopic aspects of superconductivity.

Download or read book The Action Research Planner written by Stephen Kemmis and published by Springer Science & Business Media. This book was released on 2013-11-12 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fully-updated and reworked version of the classic book by Stephen Kemmis and Robin McTaggart, now joined by Rhonda Nixon, The Action Research Planner is a detailed guide to developing and conducting a critical participatory action research project. The authors outline new views on ‘participation’ (based on Jürgen Habermas’s notion of a ‘public sphere’), ‘practice’ (as shaped by practice architectures), and ‘research’ (as research within practice traditions). They provide five extended examples of critical participatory action research studies. The book includes a range of resources for people planning a critical participatory research initiative, providing guidance on how to establish an action research group and identify a shared concern, research ethics, principles of procedure for action researchers, protocols for collaborative work, keeping a journal, gathering evidence, reporting, and choosing academic partners. Unlike earlier editions, The Action Research Planner focuses specifically on critical participatory action research, which occupies a particular (critical) niche in the action research 'family'. The Action Research Planner is an essential guide to planning and undertaking this type of research.

Download or read book Flexoelectricity in Liquid Crystals written by Agnes Buka and published by World Scientific. This book was released on 2013 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book intends to give a state-of-the-art overview of flexoelectricity, a linear physical coupling between mechanical (orientational) deformations and electric polarization, which is specific to systems with orientational order, such as liquid crystals. Chapters written by experts in the field shed light on theoretical as well as experimental aspects of research carried out since the discovery of flexoelectricity. Besides a common macroscopic (continuum) description the microscopic theory of flexoelectricity is also addressed. Electro-optic effects due to or modified by flexoelectricity as well as various (direct and indirect) measurement methods are discussed. Special emphasis is given to the role of flexoelectricity in pattern-forming instabilities. While the main focus of the book lies in flexoelectricity in nematic liquid crystals, peculiarities of other mesophases (bent-core systems, cholesterics, and smectics) are also reviewed. Flexoelectricity has relevance to biological (living) systems and can also offer possibilities for technical applications. The basics of these two interdisciplinary fields are also summarized.

Download or read book Nanomaterials For Energy Conversion And Storage written by Dunwei Wang and published by World Scientific. This book was released on 2017-11-10 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of nanomaterials in energy conversion and storage represents an opportunity to improve the performance, density and ease of transportation in renewable resources. This book looks at the most recent research on the topic, with particular focus on artificial photosynthesis and lithium-ion batteries as the most promising technologies to date. Research on the broad subject of energy conversion and storage calls for expertise from a wide range of backgrounds, from the most fundamental perspectives of the key catalytic processes at the molecular level to device scale engineering and optimization. Although the nature of the processes dictates that electrochemistry is a primary characterization tool, due attention is given to advanced techniques such as synchrotron studies in operando. These studies look at the gap between the performance of current technology and what is needed for the future, for example how to improve on the lithium-ion battery and to go beyond its capabilities.Suitable for students and practitioners in the chemical, electrochemical, and environmental sciences, Nanomaterials for Energy Conversion and Storage provides the information needed to find scalable, economically viable and safe solutions for sustainable energy.

Download or read book School and Classroom Organization written by Robert E. Slavin and published by Routledge. This book was released on 1989 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: First Published in 1988. Routledge is an imprint of Taylor & Francis, an informa company.

Download or read book Routledge International Handbook of Ignorance Studies written by Matthias Gross and published by Routledge. This book was released on 2015-05-15 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: Once treated as the absence of knowledge, ignorance today has become a highly influential topic in its own right, commanding growing attention across the natural and social sciences where a wide range of scholars have begun to explore the social life and political issues involved in the distribution and strategic use of not knowing. The field is growing fast and this handbook reflects this interdisciplinary field of study by drawing contributions from economics, sociology, history, philosophy, cultural studies, anthropology, feminist studies, and related fields in order to serve as a seminal guide to the political, legal and social uses of ignorance in social and political life. Chapter 33 of this book is freely available as a downloadable Open Access PDF under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 license available here: https://tandfbis.s3-us-west-2.amazonaws.com/rt-files/docs/Open+Access+Chapters/9780415718967_oachapter33.pdf

Download or read book Nonlinear Optical Materials written by Jerome V. Moloney and published by Springer Science & Business Media. This book was released on 1998-08-13 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical methods play a significant role in the rapidly growing field of nonlinear optical materials. This volume discusses a number of successful or promising contributions. The overall theme of this volume is twofold: (1) the challenges faced in computing and optimizing nonlinear optical material properties; and (2) the exploitation of these properties in important areas of application. These include the design of optical amplifiers and lasers, as well as novel optical switches. Research topics in this volume include how to exploit the magnetooptic effect, how to work with the nonlinear optical response of materials, how to predict laser-induced breakdown in efficient optical devices, and how to handle electron cloud distortion in femtosecond processes.

Download or read book Diffusion in Materials DIMAT 2011 written by I. Bezverkhyy and published by . This book was released on 2012 with total page 0 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.