Understanding Carbon Nanotubes doc

[...]... graphitizing carbons [56] (oil derivatives carbons, pitch-based carbon fibers for example) down to turbostratic non graphitizing carbons (hard carbons such as glassy carbons or even PANbased fibers) P is directly connected to the thickness of the carbon layer stack (Lc ) determined through (00l ) Bragg reflections [65] 1.3.4 Textures Resulting of Process in Gaseous or Vapor Phases – Pyrocarbons and pyrographites... the situation the best way is to cite Le Chatelier’s book ‘Le¸ons sur le Carbone’ written one century ago [7], where c the following statement is given ‘Le carbone non combin´ se pr´sente sous des e e formes tr`s curieuses: carbone amorphe, graphite et diamant’ – ‘uncombined e carbon is found under very inquiring forms: amorphous carbon, graphite and diamond’ (lesson 2, page 35) Soon after the discovery... France jthibault@cea.fr 1 Polymorphism and Structure of Carbons P Delha`s, J.P Issi, S Bonnamy and P Launois e Abstract In this chapter, our purpose is to introduce carbon materials, situating the nanotubes inside this polymorphic zoo We aim at giving the reader the basic notions on carbon materials structural and physical properties, necessary for the understanding of the following chapters The introductory... carbons as witnesses of the universe and earth histories Inorganic species and in particular carbonaceous ones are found in extraterrestrial environments as for example presolar grains in meteorites as diamond particles, and carbon type aggregates in interstellar dusts [2] These astrophysical observations are noteworthy for elucidating the origin and the evolution of the solar system On earth the carbonaceous... chapters The introductory section gives a historical background about the peculiar carbon element and the numerous carbon materials which have been identified up to now Then in a second part a classical thermodynamic approach is presented to describe the crystalline and non-crystalline forms of carbon, up to fullerenes and nanotubes It is shown that the choice of the processing ways, including the crucial... progress in the science of carbon has lead to unexpected and fascinating discoveries The so called amorphous carbons, already quoted by Le Chatellier, were intensively studied as demonstrated by the numerous publications on the subject (see Sect 1.3) Other forms of carbons have been evidenced which are extending this curious atomic polymorphism One dimensional, chain-like polymers of carbon atoms were noticed... different forms of carbon and in particular nanotubes (see Chap 2) The thermodynamic phase diagram of the carbon element has been established after several decades of experimental works [16], as presented in Fig 1.4 This (T,P ) general presentation is representative of the different allotropic forms Firstly the stable thermodynamic phase under ambient conditions is 1 Polymorphism and Structure of Carbons 7 Fig... high pressures [31] 1 Polymorphism and Structure of Carbons 11 Fig 1.6 (P,T ) phase diagram of pressure polymerized phases of C60 ; the arrows show P and T paths starting from the C60 glass (gc), simple cubic (sc) or facecentred cubic (fcc) phases respectively (adapted from [28]) 1.2.4 Carbon Nanotubes: Structures and Defects The crucial role of the carbon orbital hybridization and coordination number... hybridization and coordination number has been introduced in Sect 1.1.4 Infinite single-walled nanotubes are seamless cylinders at the surface of which carbon atoms are organized in a honeycomb lattice Their coordination number is three (z = 3) and the surface curvature induces some s-p hybridization Moreover, carbon nanotubes (NT) are one dimensional systems which present specific, original structureproperties... structure, one should mention that other carbon nano-objects have also been found to exist since the discovery of cylindrical carbon nanotubes – our school case One may cite for instance different morphologies such as the scrolled MWNTs [44], MWNTs and SWNTs with polygonal cross sections [45–48], nanocones [48], nanohorns [49], coils [50] and even torii [51] 1.3 Non-Crystalline Carbons 1.3.1 Definitions As already . cylinders. Two years later, single-wall carbon nanotubes were synthesized by adding metal particles to the carbon electrodes. An electric arc produced between two carbon electrodes at different chem- ical. a tool to produce carbon structures for more than forty years. This method was originally developed in 1960 by R. Bacon for the synthesis of carbon whiskers. Although carbon nanotubes were probably. . . . . . . . . . . . . 199 4.2 Electronic Properties of Carbon Nanotubes . . . . . . . . . . . . . . . . . . . . . . 217 4.3 Non-CarbonNanotubes 227 4.4 Monitoring the Electronic Structure of