Carbon Nanotube Synthesis and Organization

Abstract

The synthesis, sorting and organization of carbon nanotubes are major challengestoward future applications. This chapter reviews recent advances in these topics,addressing both the bulk production and processing of carbon nanotubes, and theirorganization into ordered structures, such as fibers, and aligned arrays on surfaces.The bulk synthetic methods are reviewed with emphasis on the current advancestoward mass production and selective synthesis. New approaches for the sorting ofcarbon nanotubes by structure and properties are described in the context of thespecific physical or chemical interactions at play, and referring to the characterizationmethods described in the contribution by Jorio et al. Recent advances in theorganization of carbon nanotubes into fibers are reviewed, including methodsbased on spinning from solution, from dry forests, and directly from the gasphase during growth. The organization of carbon nanotubes on surfaces,as a critical prerequisite toward future applications in nanoelectronics, isreviewed with particular emphasis given to the synthesis of both vertically andhorizontally aligned arrays. Vertically aligned growth has been recently boosted bythe development of highly efficient catalytic processes. Horizontally alignedgrowth on surfaces can yield a whole new array of carbon-nanotube patterns,with interesting physical properties and potential applications. Differentmechanisms of horizontally aligned growth include field- and flow-directedgrowth, as well as recently developed methods of surface-directed growth onsingle-crystal substrates by epitaxial approaches. The proposed mechanismspertinent to each technique are discussed throughout this review, as well astheir potential applications and critical aspects toward future progress.