Download or read book Optical Absorption and Electronic Properties of Individual Carbon Nanotubes written by Jean-Christophe Blancon and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, we report on the experimental investigation of the optical properties of single- and double-wall carbon nanotubes. Despite numerous studies performed using photoluminescence or Raman and Rayleigh scattering, knowledge of their optical response is still partial. In particular direct quantitative measurement of their absorption cross-section has not been achieved yet. Using spatial modulation spectroscopy we have determined, over a broad optical spectral range, the spectrum and amplitude of the absorption cross-section of identified individual single- and double-wall carbon nanotubes. These quantitative measurements permit the determination of the oscillator strength of the different excitonic resonances. Furthermore, investigation of the same nanotube, either a single-wall or double-wall nanotube, freestanding or deposited on a substrate shows large broadening with increase of oscillator strength of the excitonic resonances, as well as stark weakening of polarization dependent antenna effects, due to nanotube-substrate interaction. Similar study on nanotube bundles and double-wall nanotubes demonstrate the importance of inter-tube and inter-wall exciton coupling effects which seem to be of different nature in these two types of sample. The second part of this thesis studies electrical transport in carbon nanotube bundles under high pressure condition and low temperature. The behavior of nanotubebased field-effect transistors has been investigated, in the classical and Coulomb blockade regime, under gas-pressure up to 0.9 GPa. Overall, this dissertation communicates on the quantitative analysis of the absorption and electronic properties of carbon nanotubes and how they are influenced by various environmental effects such as dielectric screening, stress induced strain, hydrostatic pressure, or chemical doping. The novelty of this work is to address these issues at the single nanotube level.
Download or read book Investigations Into the Optical Properties of Individual Air suspended Single walled Carbon Nanotubes written by Mark William Brennan Wilson and published by . This book was released on 2008 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Single-walled carbon nanotubes are naturally-forming nanostructures that have attracted considerable recent research interest due to their unique opto-electronic properties and comparative ease of fabrication. Two-thirds of nanotube species are semiconductors due to symmetry conditions imposed by their pseudo-one-dimensional tubular structure, and exhibit band-gap photoluminescence when isolated from their environment. Despite their elegant structural simplicity, fundamental properties of carbon nanotubes, such as their intrinsic quantum efficiency, non-linear excitonic recombination mechanisms, and the role of environmental effects, continue to be disputed in the literature. The design of an apparatus capable of observing nanotube photoluminescence is presented, along with conclusive proof of the observation of a single (9,8)-chirality nanotube in the form of spectral, spatial, and polarization-dependent measurements. The dependance of the excitation and emission spectra of a single nanotube on the excitation intensity is explored and the emission spectra found to be described by a Gaussian peak function, in contrast to previously-reported results. The unexpected ability to cause redshifts in the emission spectrum via the ambient humidity is discovered, which has consequences on experimental best practices. Photoluminescence quantum efficiencies are measured to be 4"2% and 13"6% for two different nanotubes. This is at the high end of the range for comparable literature results, and supports the validity of a recent literature value for the effective atomic absorption coefficient for carbon, AC=1.6 x 10^- 3nm^2, which is ten times greater than previous literature values. Pulsed power dependence studies show that the PL emission undergoes 'hard' saturation at an excitation intensity of 0.5 x 10^12photons/pulse/cm2, which is at least 100 times lower than previous reports and provides insight into non-linear decay dynamics. A novel theoretical model is developed to explain this saturation process, which yields an absorption co-efficient of AC=1.2"0.3 x 10^ - 3nm^2 as a fit parameter. Time-resolved photoluminescence dynamics are explored using femtosecond excitation correlation spectroscopy. Results suggest that the one-body decay processes are bi-exponential, with time constants of 31"4ps and 313"61ps, but also highlight the limitations of this technique in observing the expected very rapid (~1 ps) two-body Auger recombination process.
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 Carbon Nanotubes written by Siva Yellampalli and published by BoD – Books on Demand. This book was released on 2011-07-20 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon nanotubes are one of the most intriguing new materials with extraordinary properties being discovered in the last decade. The unique structure of carbon nanotubes provides nanotubes with extraordinary mechanical and electrical properties. The outstanding properties that these materials possess have opened new interesting researches areas in nanoscience and nanotechnology. Although nanotubes are very promising in a wide variety of fields, application of individual nanotubes for large scale production has been limited. The main roadblocks, which hinder its use, are limited understanding of its synthesis and electrical properties which lead to difficulty in structure control, existence of impurities, and poor processability. This book makes an attempt to provide indepth study and analysis of various synthesis methods, processing techniques and characterization of carbon nanotubes that will lead to the increased applications of carbon nanotubes.
Download or read book Carbon nanotubes and graphene for photonic applications written by K. Matsuda and published by Elsevier Inc. Chapters. This book was released on 2013-08-31 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fundamental electronic states and optical properties of single-walled carbon nanotubes are briefly explained in this chapter. Moreover, the novel optical properties of carbon nanotubes revealed by advanced laser spectroscopy (single-nanotube spectroscopy and time-resolved spectroscopy) are introduced. Due to the enhanced Coulomb interaction, the optically generated electron-hole pair forms a strongly bound ‘exciton’ state, analogous to the hydrogen-like state in the carbon nanotubes. The striking features of excitons in the carbon nanotube, such as singlet-dark states and triplet states, which dominate the optical properties, are described in this chapter.
Download or read book Optical and Mechanical Properties of Single walled Carbon Nanotubes written by Matthew S. Marcus and published by . This book was released on 2004 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Carbon Nanotubes written by Stephanie Reich and published by John Wiley & Sons. This book was released on 2008-09-26 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon nanotubes are exceptionally interesting from a fundamental research point of view. Many concepts of one-dimensional physics have been verified experimentally such as electron and phonon confinement or the one-dimensional singularities in the density of states; other 1D signatures are still under debate, such as Luttinger-liquid behavior. Carbon nanotubes are chemically stable, mechanically very strong, and conduct electricity. For this reason, they open up new perspectives for various applications, such as nano-transistors in circuits, field-emission displays, artificial muscles, or added reinforcements in alloys. This text is an introduction to the physical concepts needed for investigating carbon nanotubes and other one-dimensional solid-state systems. Written for a wide scientific readership, each chapter consists of an instructive approach to the topic and sustainable ideas for solutions. The former is generally comprehensible for physicists and chemists, while the latter enable the reader to work towards the state of the art in that area. The book gives for the first time a combined theoretical and experimental description of topics like luminescence of carbon nanotubes, Raman scattering, or transport measurements. The theoretical concepts discussed range from the tight-binding approximation, which can be followed by pencil and paper, to first-principles simulations. We emphasize a comprehensive theoretical and experimental understanding of carbon nanotubes including - general concepts for one-dimensional systems - an introduction to the symmetry of nanotubes - textbook models of nanotubes as narrow cylinders - a combination of ab-initio calculations and experiments - luminescence excitation spectroscopy linked to Raman spectroscopy - an introduction to the 1D-transport properties of nanotubes - effects of bundling on the electronic and vibrational properties and - resonance Raman scattering in nanotubes.
Download or read book Electronic Properties of Carbon Nanotubes written by Leroy Sidney and published by . This book was released on 2016-04 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon nanotubes (CNTs) are tubular cylinders of carbon atoms that have extraordinary mechanical, electrical, thermal, optical and chemical properties. CNTs typically have diameters ranging from 1 nanometer (nm) up to 50 nma nanometer is one thousand millionth of a meter. Typical CNT lengths are several micronsseveral thousand nanometers long; by contrast, Nanocomp's produced fibers are measured in millimetersthousands of times longer than all other commercially produced CNTs. They take the form of cylindrical carbon molecules and have novel properties that make them potentially useful in a wide variety of applications in nanotechnology, electronics, optics and other fields of materials science. They exhibit extraordinary strength and unique electrical properties, and are efficient conductors of heat. In the powdery format offered by all CNT producers (but for NTI), applications are limited to the properties possible by this form factore.g. additive active ingredients in semiconductors, liquid crystal displays (LCDs), sensors, and other uses in which these powders add some level of functional performance. Due to its fiber length and its form factors, NTI delivers strength and conductivity unlike any other commercial CNT producer, and so can address a much broader array of applications for which its material rivals copper and aluminum in conductivity, and steel, aluminum, carbon fibers and glass composites where strength and lightweight matter. Carbon nanotubes have been a subject of exhaustive research for a wide range of applications. The purpose of this book entitled Properties of Carbon Nanotubes is to give in-depth understanding of the physics and electronic structure of carbon nanotubes. This book discusses fabrication techniques followed by an analysis on the physical properties of carbon nanotubes, including density of states and electronic structures. Eventually, the book follows a significant amount of work in the industry applications of carbon nanotubes.
Download or read book Electronic Properties of Carbon Nanotubes written by Jose Mauricio Marulanda and published by BoD – Books on Demand. This book was released on 2011-07-27 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon nanotubes (CNTs), discovered in 1991, have been a subject of intensive research for a wide range of applications. These one-dimensional (1D) graphene sheets rolled into a tubular form have been the target of many researchers around the world. This book concentrates on the semiconductor physics of carbon nanotubes, it brings unique insight into the phenomena encountered in the electronic structure when operating with carbon nanotubes. This book also presents to reader useful information on the fabrication and applications of these outstanding materials. The main objective of this book is to give in-depth understanding of the physics and electronic structure of carbon nanotubes. Readers of this book should have a strong background on physical electronics and semiconductor device physics. This book first discusses fabrication techniques followed by an analysis on the physical properties of carbon nanotubes, including density of states and electronic structures. Ultimately, the book pursues a significant amount of work in the industry applications of carbon nanotubes.
Download or read book Carbon nanotubes and graphene for photonic applications written by E. Gaufrès and published by Elsevier Inc. Chapters. This book was released on 2013-08-31 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: This chapter describes how the semiconducting-single-wall nanotube (SWNT) extraction affects their luminescence properties and how such properties can be exploited to fabricate optical sources emitting in near-infrared wavelengths ranging from 1 to 2μm. The main applications of carbon nanotube (CNT) lasers are aimed at optical interconnects and biophotonics. We review recent achievements in obtaining optical gain in thin films doped with CNTs. Techniques for determining optical gain in CNTs are considered with particular focus on the variable strip length (VSL) method and choices to integrate nanotubes in the optical waveguide are discussed.
Download or read book Electronic and Optical Properties of Graphite Related Systems written by Chiun-Yan Lin and published by CRC Press. This book was released on 2017-12-12 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an overview of electronic and optical properties of graphite-related systems. It presents a well-developed and up-to-date theoretical model and addresses important advances in essential properties and diverse quantization phenomena. Key features include various Hamiltonian models, dimension-enriched carbon-related systems, complete and unusual results, detailed comparisons with the experimental measurements, clear physical pictures, and further generalizations to other emergent 2D materials. It also covers potential applications, such as touch-screen panel devices, FETs, supercapacitors, sensors, LEDs, solar cells, photodetectors, and photomodulators.
Download or read book The Effects of Local Chemistry on the Growth and Electronic Properties of Carbon Nanotubes written by Jason M. Simmons and published by . This book was released on 2006 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Carbon Nanotubes written by Ado Jorio and published by Springer Science & Business Media. This book was released on 2007-12-18 with total page 734 pages. Available in PDF, EPUB and Kindle. Book excerpt: Building on the success of its predecessor, Carbon Nanotubes: Synthesis, Structure, Properties and Applications, this second volume focuses on those areas that have grown rapidly in the past few years. Contributing authors reflect the multidisciplinary nature of the book and are all leaders in their particular areas of research. Among the many topics they cover are graphene and other carbon-like and tube-like materials, which are likely to affect and influence developments in nanotubes within the next five years. Extensive use of illustrations enables you to better understand and visualize key concepts and processes.
Download or read book Chalcogenide written by Abhay Kumar Singh and published by CRC Press. This book was released on 2021-04-27 with total page 467 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is introductory book for researchers, scientists and students in the area of organic and inorganic composite materials. This book has addressed timely the innovative topic "chalcogenide-multiwalled carbon nanotubes and chalcogenide-bilayer graphene" composite materials under a glassy regime. This book will give a clear idea on the concepts of the newly established composite materials area, by providing interpretations of inside physio-chemical mechanism. The remarkable landmark innovations related to this newly introduced research field are included in this book. Additionally, the possible futuristic applications in the area of nanoelectronics, optoelectronics, biomedical etc are also addressed.
Download or read book The Theory of DNA wrapped Single walled Carbon Nanotubes for Electronic and Optical Applications written by Stacy E. Snyder and published by . This book was released on 2008 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the framework of tight-binding theory, we investigate modulation of the electronic and optical properties of single-walled carbon nanotubes helically wrapped with single-stranded DNA. We develop a model to simulate DNA-carbon nanotube hybrids with a variety of nanotube structures and DNA wrapping geometries. We determine band structure changes due to the charged helical wrap for semiconducting and metallic nanotubes. For metallic nanotubes, DNA induces a small bandgap; for semiconducting tubes, the gap typically decreases. To quantify the robustness of the hybrid structures, we compute the polarization component of the energy of cohesion. A typical value of this energy is 0.5 eV per DNA base, evidence of the marked stability of the structures. Optical absorption calculations predict that nanotube symmetry breaking in the Coulomb potential of the ionized DNA backbone can lift optical selection rules, qualitatively changing the one-electron absorption spectrum for light polarized across the SWNT. In addition, circular dichroism is predicted for DNA wrapped single-walled carbon nanotubes, even when the nanotube itself is achiral. These changes may be used for experimental determination of the presence of DNA wrapping.
Download or read book Carbon nanotubes and graphene for photonic applications written by J. Pan and published by Elsevier Inc. Chapters. This book was released on 2013-08-31 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon nanotubes are exceptionally photostable fluorophores that emit in the near infrared range. Their novel optical properties make them particularly appealing for applications in biosensing. This chapter focuses on the state-of-the-art development of optical biosensors based on single-walled carbon nanotubes (SWCNTs); also, it draws attention to the basic photophysics of SWCNTs, optical-sensing mechanisms, and surface functionalization principles. The concerted efforts from the research community in the past decade have enabled the realization of several SWCNT-based optical biosensors that provide real-time, non-invasive analyte detection. We review the performance of these biosensors with regard to their sensitivity, selectivity and response time, and highlight the prospects and challenges of constructing biosensors for more advanced sensing applications.
Download or read book Ultrafast Dynamics of Individual Air suspended Single walled Carbon Nanotube written by Tam Q. Nhan and published by . This book was released on 2008 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thorough understanding of the electronic and optical properties of single-walled carbon nanotubes (SWCNTs) will no doubt benefit future technological applications. Since the discovery of band gap photoluminescence from isolated semiconducting SWCNTs, significant progresses in studying the optical properties of SWCNTs have been made (e.g. linear polarization along the tube axis for the absorption and emission of light, excitonic nature in SWCNT excitation). However, there are still several controversial parameters of SWCNTs (e.g. quantum efficiency, absorption cross section, radiative lifetime, and Auger recombination lifetime). With the advancement in SWCNT sample preparation, studies of SWCNT intrinsic properties have shifted from ensemble to a single tube level, in which the ambiguities in elucidating intrinsic properties posed by the assortment of different tube species can be minimized. By examining individual SWCNTs suspended in air, in contrast to micelle-encapsulated SWCNTs, we believe that the environmental effects can be reduced. This thesis will demonstrate the capability of doing spectroscopy on a single semiconducting air-suspended SWCNT. In continuous-wave excitation, the photoluminescence excitation map and high resolution photoluminescence (PL) image of a SWCNT can be constructed, and PL polarization is proven. Quantum efficiency of 5% is experimentally estimated for (9,8) and (10,8) chiral SWCNTs. Pulse excitation allows us to study the intrinsic exciton dynamics of a SWCNT. To gain insight into exciton nonlinear decay processes, PL saturation in pump power dependence measurement is investigated and compared to the simulated results from stochastic models of exciton dynamics. Femtosecond excitation correlation spectroscopy with 150 fs time resolution is employed to time-resolve the PL of a single tube suspended in air.
