No other known material comes closer to an ideal one-dimensional system than single-wall carbon nanotubes. In this dissertation, we explore the fascinating new physics characterizing these new nanostructures. After a comprehensive and accessible introduction to the electronic and optical properties of carbon nanotubes, we present our major experimental result: at low-temperature, carbon nanotubes can act as perfect single photon sources. This observation has catapulted nanotubes to a promising candidate for the generation of tunable single photons in quantum information applications. We then investigate the interaction of localized optical excitations with the mechanical vibrations of the nanotube. Here again, the low-dimensionality of the system yields to dramatic effects with no analog in bulk materials. Motivated by the unique properties of carbon nanostructures, we also present a proposal for all-optical spin manipulation in nanotubes and explore the possibility of optomechanical cooling of a nanotube resonator to the quantum ground state. This book brings the reader on a journey through the latest developments in quantum optics with carbon nanostructures.
This volume is devoted to mostly to nanotubes, unique synthetic nanoscale quantum systems whose physical properties are often singular (i.e. record-setting). Nanotubes can be formed from a myriad of atomic or molecular species, the only requirement apparently being that the host material or wall fabric be configurable as a layered or sheet-like structure. Nanotubes with sp2-bonded atoms such as carbon, or boron together with nitrogen, are the champions of extreme mechanical strength, electrical response (either highly conducting or highly insulating), and thermal conductance. Carbon nanotubes can be easily produced by a variety of synthesis techniques, and for this reason they are the most studied nanotubes, both experimentally and theoretically. Boron nitride nanotubes are much more difficult to produce and only limited experimental characterization data exist. Indeed, for boron nitride nanotubes, theory is well ahead of experiment. For these reasons this volume deals largely with carbon nanotubes. Conceptually, the "building block" for a carbon nanotube is a single sheet of graphite, called graphene. Recently, it has become possible to experimentally isolate such single sheets (either on a substrate or suspended). This capability has in turn fueled many new theoretical and experimental studies of graphene itself. It is therefore fitting that this volume contains also a chapter devoted to graphene.- Comprehension- Overview- Highlights in the field
The work described in this thesis concerns the filling of Single-Walled Carbon Nanotubes (SWNTs) with semiconductor compounds (HgTe, HgxCd1-xTe, InSb, SnSe). Once successfully introduced into the SWNTs, the fillings were structurally analysed via focal series restoration High Resolution Transmission Electron Microscopy (HRTEM). For each system, models were proposed, simulated and compared with original restored phase images.
"Carbon Nanotubes" provides an extensive description of carbon nanotubes in terms of their structures, properties, synthesis, characterization and applications. This book includes a comprehensive review of synthesis methods of single and multi-wall carbon tubes and their technological applications in microscopes, sensors and microelectronics. It is presenting basic knowledge appealing to graduate and postgraduate researchers and scientists.
This book addresses the inherent difficulty in synthesizing single-walled carbon nanotubes (SWCNTs) with well-defined electronic and solubility properties through functionalization, introduction of dopants, topological defects, and intercalation of metals. Depending on the desired application, one can modify the electronic and solubility properties of SWCNTs through an appropriate introduction of imperfections. This scheme broadens the application areas of SWCNTs.
Carbon nanotubes are interesting nanomaterials of cylindrical shapes and are structurally equivalent to a seamless folded single sheet of graphite having diameters in some tens of nanometers. They are fascinating for mechanical engineers because of their nearly highest per unit mass Young’s modulus and strength. They were first synthesized by Iijima in 1991 and ever since then enormous effort was dedicated to characterize them and find their utility in engineering applications. Multiwalled Carbon nanotubes (MWCNTs) are multi-layered single wall cylinders with common axis and are more easily available. The work presented here is aimed to give an elementary exposure to the methods used by experimentalists to measure the dimensions of carbon nanotubes in all forms of single walled carbon nanotubes(SWCNTs) and MWCNTs including those that are functionalized. The use of Atomic Force Microscope (AFM) and Nanomanipulator to measure the diameter and length as well as to study the stress-strain relations is demonstrated and the results are analysed to highlight the methodology. A simple theoretical understanding of the structure of all chirality Carbon Nanotubes has also been made.
The study of photophysical, electronic, and compositional properties of single-walled carbon nanotubes (SWCNTs), bulk nanotube samples, and graphene oxide is described. We show effects of external electric fields, causing dramatic, reversible decreases in SWCNT emission intensity. Quenching efficiency was related to exciton binding energy suggesting field-induced exciton dissociation. Further, we describe a new method developed to measure the fraction of semiconducting SWCNTs in nanotube samples. The results provide important information about sample electronic compositions that can also guide SWCNT growth methods. Next is the study of SWCNT absorption backgrounds. A number of extrinsic perturbations such as ultrasonication, functionalization, carbon impurities, and SWCNT aggregation were applied and their contributions quantified together with background component from metallic SWCNTs. These results can be used to minimize and evaluate SWCNT absorption backgrounds. Finally, a strong pH dependence of graphene oxide photoluminescence was observed. Sharp and structured excitation/emission features were obtained in basic conditions and assigned to quasi-molecular fluorophores.
Nanoelectromechanical systems (NEMS) in which a nanomechanical resonator is coupled to a mesoscopic conductor, such as a single-electron transistor, form a new class of mesoscopic quantum systems in which there is a fascinating interplay between the electrical and mechanical degree of freedom. Coupling to nanomechanical degrees of freedom can modify the transport properties of mesoscopic conductors substantially, giving rise to a number of novel phenomena such as electron shuttling effects. Sensors continue to make significant impact in everyday life. With the advent of nanotechnology, research is underway to create miniaturized sensors. The application of carbon nanotubes in next-generation of sensors has the potential of revolutionizing the sensor industry due to their inherent properties such as small size, high strength, high electrical and thermal conductivity, and high specific surface area. Carbon nanotubes which are modeled under axial strain and torsion have predictable chirality dependent band gap changes in response to strain. The present thesis shows how we use carbon nanotub-based NEMS resonators as bio-molecules detection and also as strain sensor.
Carbon nanotubes (CNTs) have received much attention from both the scientific and industrial communities due to their structural properties and unique morphology. There has also been growing interest in vertically aligned single walled carbon nanotubes (VA-SWNTs) because of their suitability for building devices such as hydrogen storage and super capacitors. Various methods including chemical vapor deposition (CVD) have been developed for growing VA-SWNTs. Among them is alcohol catalytic CVD which is well known for its economic viability, comprehensive substrates selectivity and good yield of VA-SWNTs. In order to fully understand the growth mechanism of those CNTs, an examination of the role of inputs like hydrocarbon flow rate, reaction time, chamber temperature, and pressure is essential. This work studies the controllability of VA-SWNTs growth by a hybrid process model of an experimental design and an artificial neural network (ANN).
The rapid progress in the field of organic conducting materials has found possible applications for sensors and molecular electronics. Among them both conducting polymers and carbon nanotubes, specifically Single Walled Carbon Nanotubes and Multi Walled Carbon Nanotubes, are good candidates for these applications. Their associations can lead to the synthesis of materials called nanocomposites which resemble the whole physical and chemical properties of the starting ones. This book is therefore focused on the fabrication of nanocomposites materials, based on polyaniline derivatives and multi-walled carbon nanotubes, by means of standardized oxidative polymerization, and the subsequent characterizations by different techniques to asses the physical and chemical properties of the synthesised materials.
This book describes experiments on the synthesis of single wall carbon nanotubes (SWNTs), fabrication of ultraclean CNT devices, and study of electronic properties of CNTs with transport measurements. The first part of this work describes the optimization of the synthesis parameters (by chemical vapor deposition - CVD) such as carbon precursors, gas flows, temperature, catalyst for the growth of high quality SWNTs. In all these parameters, the catalyst composition plays a very important role on the high selective growth of SWNTs with a narrow diameter distribution. The second part deals with the nanofabrication of ultra-clean CNT devices and the low temperature (40 mK) transport measurements of these CNT quantum dots. The level spectra of the electrons in the first shell are investigated using inelastic cotunneling spectroscopy in an axial magnetic field, which show a strong negative spin-orbit coupling of electron. We find that the sequence of electron shell filling in our case (?SO < 0) is different from which would be obtained in the pure SU(4) Kondo regime (?SO = 0). Indeed, a pure orbital Kondo effect is observed in N=2e at a finite magnetic field.
Carbon Nanotubes play a special role in the realm of carbon nanostructures. Many applications of carbon nanotubes have started coming to Adsorption of Carbon Nanotubes in recent years and this is a research direction of great promise. Therefore, a book with an Adsorption and Desorption in Carbon Nanotubes focus is especially timely. That the authors of the book have many years of experience in Adsorption in Carbon Nanotubes research and in commercial exploitation of carbon nanotubes makes this volume of even greater importance and value, as they share this expertise and experience with students, researchers, and others.
Global warming is an important problem that affects human life, animals and plants. Emissions during the combustion of fossil fuels, such as carbon dioxide, NOx, SOx etc. are reported to contribute to this problem extremely. Nowadays, alcohols and ethers are considered as attractive alternative fuels due to their good burning properties and less carbon emissions. Dimethyl ether (DME) is one of the most promising alternates of such synthetic fuels. In methanol dehydration reaction to produce DME, solid acid catalysts, such as ?-Alumina and modified ?-Alumina, Na-modified H-ZSM-5, mesoporous alumino silicate were tested. These catalysts are porous solid with low thermal conductivity. The reaction heat is difficult to be transferred and the diameter of single tube of the reactor has to be limited to several centimeters in order to control the temperature of the hot spots in the fixed bed reactors. Also carbon nanotubes (CNTs) are desirable for many applications because of their high surface area to weight ratio and excellent thermal conduction property. Through this book CNTs was used for improvement of catalysts for dehydration of methanol to DME.
This book will provide researchers with basic knowledge about synthesis of carbon nanotubes and how the several parameters affect their growth. It will also explain the different ways of surface modifications of carbon nanotubes to bring strong adhesion among the filler and matrix. Furthermore, this book will discuss about the fabrication methods of nanocomposites and their structural, thermal and mechanical properties.