![]() Also, single-wall carbon nanotube field-effect transistors (CNFETs). (5, 5) armchair nanotube, (9, 0) zigzag nanotube, and (10, 5) chiral nanotube. de HeerĪKA: Multi-wall Carbon Nanotubes (MWNTs), Single-wall Carbon Nanotubes (SWCNs), Nanotube cost, polydispersity in nanotube type, and limitations in processing and assembly methods are important barriers for some applications of single-walled nanotubes.Ĭarbon Nanotubes-the Route Toward Applications Ray H. Others are demonstrated in early to advanced devices, and one, hydrogen storage, is clouded by controversy. ![]() Some of these applications are now realized in products. ![]() Many potential applications have been proposed for carbon nanotubes, including conductive and high-strength composites energy storage and energy conversion devices sensors field emission displays and radiation sources hydrogen storage media and nanometer-sized semiconductor devices, probes, and interconnects. Carbon nanotubes are quite popular now for their prospective electrical, thermal, and even selective-chemistry applications. These properties are ideal for reinforced composites, nanoelectromechanical systems (NEMS).Ĭarbon Nanotube Transistors exploit the fact that nm- scale nanotubes (NT) are ready-made molecular wires and can be rendered into a conducting, semiconducting, or insulating state, which make them valuable for future nanocomputer design. The estimated tensile strength is 200 Giga Pascal. They are electrically conductive, which allows their use in STM and EFM (electric force microscopy), and they can be modified at their ends with specific chemical or biological groups for high resolution functional imaging.ĬNT exhibits extraordinary mechanical properties: the Young's modulus is over 1 Tera Pascal. Nanotubes elastically buckle rather than break when deformed, which results in highly robust probes. These geometrical factors also lead to reduced tip-sample adhesion, which allows gentler imaging. Their high aspect ratio provides faithful imaging of deep trenches, while good resolution is retained due to their nanometer-scale diameter. Lieber GroupĪnd an excellent description of Carbon Nanotube Tips for Atomic Force MicroscopyĬarbon nanotubes possess many unique properties which make them ideal AFM probes. The three main types are armchair, zig-zag, and chiral. These one-dimensional fibers exhibit electrical conductivity as high as copper, thermal conductivity as high as diamond, strength 100 times greater than steel at one sixth the weight, and high strain to failure.Ī nanotube's chiral angle-the angle between the axis of its hexagonal pattern and the axis of the tube-determines whether the tube is metallic or semiconducting.Ī graphene sheet can be rolled more than one way, producing different types of carbon nanotubes. Nanotubes can be either electrically conductive or semiconductive, depending on their helicity, leading to nanoscale wires and electrical components. Apart from remarkable tensile strength, nanotubes exhibit varying electrical properties (depending on the way the graphite structure spirals around the tube, and other factors, such as doping), and can be superconducting, insulating, semiconducting or conducting (metallic). The dimensions are variable (down to 0.4 nm in diameter) and you can also get nanotubes within nanotubes, leading to a distinction between multi-walled and single-walled nanotubes. These noncarbon nanotubes are most often referred to as nanowires. A commonly mentioned non-carbon variety is made of boron nitride, another is silicon. Strictly speaking, any tube with nanoscale dimensions, but generally used to refer to carbon nanotubes, which are sheets of graphite rolled up to make a tube. Nanotubes are a proving to be useful as molecular components for nanotechnology. Depending on the direction that the tubes appear to have been rolled (quantified by the 'chiral vector'), they are known to act as conductors or semiconductors. ![]() Carbon nanotubes discovered in 1991 by Sumio Iijima resemble rolled up graphite, although they can not really be made that way. Crespi Department of Physics Pennsylvania State University.Ī one dimensional fullerene (a convex cage of atoms with only hexagonal and/or pentagonal faces) with a cylindrical shape. ![]()
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