• chemical-vapor depo
  • TROY, N.Y. A chemical-vapor deposition technique has been applied to carbon nanotubes to give them unusual electronic properties, according to researchers here at Rensselaer Polytechnic Institute. (eetimes.com)
  • Carbon nanotubes were tamed by these researchers using standard chemical-vapor deposition (CVD) processes familiar to all chip makers. (eetimes.com)
  • Specifically, catalytic chemical vapor deposition was used to infiltrate metal matrices with single and multiwall carbon nanotubes using carbon monoxide and acetylene as carbon sources. (nsti.org)
  • This can be done by chemical vapor deposition using carbon monoxide. (wikipedia.org)
  • Techniques have been developed to produce carbon nanotubes in sizable quantities, including arc discharge, laser ablation, high-pressure carbon monoxide disproportionation, and chemical vapor deposition (CVD). (wikipedia.org)
  • Morinobu Endo reported CVD (Chemical Vapor Deposition) growth of nanometer-scale carbon fibers, and they also reported the discovery of carbon nanofibers, including that some were shaped as hollow tubes. (wikipedia.org)
  • A single-walled carbon nanotube was grown by chemical vapor deposition across a 10-micron gap in a silicon chip, then used in cold atom experiments, creating a blackhole like effect on single atoms. (wikipedia.org)
  • atoms
  • Because of differences in the way the familiar chicken-wire patterns of carbon atoms line up across the surface, nanotubes can either act as metals or semiconductors. (asme.org)
  • And because of differences in the way the familiar chicken-wire patterns of carbon atoms line up across the surface, nanotubes can either act as metals (potentially conducting greater current densities than copper) or semiconductors. (asme.org)
  • Carbon nanotubes, made of layers of carbon atoms, can be as small as one nanometer - one billionth of a meter - in diameter. (medgadget.com)
  • The chemical bonding of nanotubes involves entirely sp2-hybrid carbon atoms. (wikipedia.org)
  • These bonds, which are similar to those of graphite and stronger than those found in alkanes and diamond (which employ sp3-hybrid carbon atoms), provide nanotubes with their unique strength. (wikipedia.org)
  • Although covalent modifications are very stable, the bonding process disrupts the sp2 hybridization of the carbon atoms because a σ-bond is formed. (wikipedia.org)
  • So called copper nanotubes (CuNTs), developed by the Chinese Academy of Sciences, are fabricated by closely aligning individual copper atoms on a surface. (wikipedia.org)
  • This strength results from the covalent sp2 bonds formed between the individual carbon atoms. (wikipedia.org)
  • graphitic
  • Iijima, S.: Helical microtubules of graphitic carbon. (springer.com)
  • Using this three-dimensional fabrication technique, researchers at the Georgia Institute of Technology developed graphitic nanojoints on both ends of the multi-walled carbon nanotubes, which yielded a 10-fold decrease in resistivity in its connection to metal junctions. (ecnmag.com)
  • Thermal annealing of the carbon after deposition converts it to a crystalline graphitic form that significantly improves electrical conductivity. (ecnmag.com)
  • During acid oxidation, the carbon-carbon bonded network of the graphitic layers is broken allowing the introduction of oxygen units in the form of carboxyl, phenolic and lactone groups, which have been extensively exploited for further chemical functionalisation. (wikipedia.org)
  • Graphitic carbon is also used as a support material where other catalytic components may be dispersed, resulting in an increase of the surface area they expose to the chemical reactants. (wikipedia.org)
  • In the CVD process, a hot carbonaceous gas decomposes, *leaving carbon to diffuses into or around the catalyst particles*, and then nucleates a graphitic nanotube sidewall at one crystallographic face of the catalyst. (wikipedia.org)
  • In the case of the base-growth model, the initial hydrocarbon decomposition and carbon diffusion take place similar to that in the tip-growth case, but the CNT precipitation emerges out from the metal particle's apex and forms a hemispherical dome, which then extends up in the form of seamless graphitic cylinder. (wikipedia.org)
  • Radushkevich and Lukyanovich publish a paper in the Soviet Journal of Physical Chemistry showing hollow graphitic carbon fibers that are 50 nanometers in diameter. (wikipedia.org)
  • polymer
  • Carbon nanotubes have been extensively investigated for developing polymer matrix nanocomposites and a number of such nanocomposites are already being used in various applications [1, (nsti.org)
  • The nature of the carbon nanotube/polymer bonding and the curvature of the carbon nanotubes within the polymer have arisen as particular factors in the efficacy of the carbon nanotubes to actually provide any enhanced stiffness or strength to the nanocomposite. (nsti.org)
  • Therefore, electrically driven actuators of nanotube sheets are superior to the conjugated polymer actuators which involve solid-state dopant diffusion and structural changes limiting rate, cycle life and energy conversion efficiencies. (wikipedia.org)
  • The maximum strain for the carbon nanotube sheet actuators at low voltages is greater than that of the high modulus ferroelectric ceramic actuators (~0.1%), but it is lower than that of the low voltage (~0.4 V) conducting polymer actuators (~3% film direction, 20% thickness direction). (wikipedia.org)
  • Photovoltaic efficiency enhancement is proposed to be due to the introduction of internal polymer/nanotube junctions within the polymer matrix. (wikipedia.org)
  • Researchers at Rice University, Stony Brook University, Radboud University Nijmegen Medical Centre and University of California, Riverside have shown that carbon nanotubes and their polymer nanocomposites are suitable scaffold materials for bone tissue engineering and bone formation. (wikipedia.org)
  • grow nanotubes
  • Our ability to grow nanotubes in any orientation will facilitate [building] those kinds of devices," said Ramanath. (eetimes.com)
  • Our process is the world's first to grow nanotubes in any direction that we want vertical, horizontal or at an oblique orientation and this can be predetermined before the nanotubes begin to grow. (eetimes.com)
  • Most thermal CVD processes grow nanotubes by the root or base growth method. (wikipedia.org)
  • junctions
  • The anomaly shows unusual temperature dependence and can be caused by tunneling of charge carriers through numerous nanotube junctions enhanced by temperature gradients induced by measuring currents. (nanowerk.com)
  • The high electric field at these junctions can split up the excitons, while the single-walled carbon nanotube (SWCNT) can act as a pathway for the electrons. (wikipedia.org)
  • arrays
  • Nanowerk Spotlight ) Vertical arrays of carbon nanotubes, called 'forests', are a common type of three-dimentional (3D) nanotube assembly that researchers work with in their labs. (nanowerk.com)
  • As Kozlov points out, the study shows that three-domensional carbon nanotube assemblies may provide the functionality of conventional metal-insulator-metal tunnel junction arrays that are normally fabricated by a lithographic procedure. (nanowerk.com)
  • molecules
  • Materials scientists have long known that carbon-based molecules can possess extreme properties-after all, diamonds are pure carbon. (asme.org)
  • When the secondary electrons interact with hydrocarbon precursor molecules introduced into the SEM chamber, carbon is deposited in desired locations. (ecnmag.com)
  • Under wetting conditions, water molecules are transported e±ciently through nanotubes. (nsti.org)
  • Implications on the design of nanotube channels for small molecules and protons will be discussed. (nsti.org)
  • These cylindrical carbon molecules have unusual properties, which are valuable for nanotechnology, electronics, optics and other fields of materials science and technology. (wikipedia.org)
  • Carbon nanotubes modified with acyl chloride react readily with highly branched molecules such as poly(amidoamine), which acts as a template for silver ion and later being reduced by formaldehyde. (wikipedia.org)
  • Carbon nanotubes are very good conductors of both electricity and heat, and are also very strong and elastic molecules in certain directions. (wikipedia.org)
  • This process was developed by Dr. Richard Smalley and co-workers at Rice University, who at the time of the discovery of carbon nanotubes, were blasting metals with a laser to produce various metal molecules. (wikipedia.org)
  • Nanotubes synthesized hollow carbon molecules and determined their crystal structure for the first time in the soot of arc discharge at NEC, by Japanese researcher Sumio Iijima. (wikipedia.org)
  • nanocomposites
  • We have developed a scaleable chemical vapor infiltration technique [4, which can be combined with electrophoretic deposition to form metal matrix nanocomposites with enhanced yield strength and varying levels of carbon nanotube loading. (nsti.org)
  • driven actuators
  • The maximum actuator strain for electrically driven actuators of carbon nanotube sheets can be improved up to 0.7% in a 1 M electrolyte once the sheets are annealed in an inert atmosphere at very high temperatures (1100 oC) in contrast to once reported 0.1% or less for low electrochemical potentials (~1 V or less). (wikipedia.org)
  • electron
  • These scanning electron micrographs show nanotube ribbons being made at the University of Texas at Dallas. (asme.org)
  • Atom-by-atom, we can build the connection where the electron beam strikes right near the open end of the carbon nanotubes," Fedorov explained. (ecnmag.com)
  • The resistance R of one single-walled carbon nanotube (SWCNT) can be expressed by R = Rc + Rq (1+L/Lmfp) where Rc is an extrinsic contact resistance, Rq is the quantum resistance (6.5 kΩ) which comes from the connection of 1D material to a 3D metal, L is the CNT length and Lmfp is the mean free path of the electron. (wikipedia.org)
  • Due to their nanoscale dimensions, electron transport in carbon nanotubes will take place through quantum effects and will only propagate along the axis of the tube. (wikipedia.org)
  • Swiss researchers are the first to demonstrate the electron emission properties of carbon nanotubes. (wikipedia.org)
  • The first transmission electron microscope observation of radial elasticity suggested that even the van der Waals forces can deform two adjacent nanotubes. (wikipedia.org)
  • deposition
  • Prior to deposition, the ends of the nanotubes are opened using an etching process, so the deposited carbon grows into the open end of the nanotube to electronically connect multiple shells. (ecnmag.com)
  • Relative research are deposition of palladium and platinum particles on activated carbon, using a poly-acrylate anchor. (wikipedia.org)
  • The catalytic vapor phase deposition of carbon was reported in 1952 and 1959, but it was not until 1993 that carbon nanotubes were formed by this process. (wikipedia.org)
  • catalysts
  • Catalysts are typically metals that have high carbon solubility at high temperatures and that exhibit a high carbon diffusion rate, such as iron (Fe), cobalt (Co), and nickel (Ni). (wikipedia.org)
  • The method is similar to arc discharge in that both use ionized gas to reach the high temperature necessary to vaporize carbon-containing substances and the metal catalysts necessary for the ensuing nanotube growth. (wikipedia.org)
  • Groups led by Donald S. Bethune at IBM and Sumio Iijima at NEC independently discover single-wall carbon nanotubes and methods to produce them using transition-metal catalysts. (wikipedia.org)
  • researchers
  • Researchers have envisioned a future generation of hybrid devices based on traditional integrated circuits but using interconnects based on carbon nanotubes. (ecnmag.com)
  • Researchers from Stanford University said that they had successfully built a carbon nanotube computer and their research paper published on 25 September 2013 in the journal Nature. (wikipedia.org)
  • Harvard researchers have used the electrostatic attraction principle to design on/off switches for their proposed nanotube Random Access Memory devices. (wikipedia.org)
  • Researchers of AlliedSignal initially demonstrated the possibility of electrically powered actuators fabricated by carbon nanotube sheets. (wikipedia.org)
  • functionalization
  • These nanotubes function with a larger inner volume to be used as the drug container, large aspect ratios for numerous functionalization attachments, and the ability to be readily taken up by the cell. (wikipedia.org)
  • properties
  • The various beneficial properties of carbon nanotubes makes them the most attractive material to base such nanomotors on. (wikipedia.org)
  • Nanotubes have fascinating electrical properties, but for them to be used in real devices, you need a process like ours to make really big architectures from these very small building blocks," said assistant professor Ganapathiraman Ramanath, co-developer of the nanotube architecture with associate professor Pulickel Ajayan, both in the materials science department at Rensselaer Polytechnic Institute. (eetimes.com)
  • This method enables the superior control of the relative placement of functionalities on the nanotube surface while still preserving nearly all of the nanotube's intrinsic properties. (nsti.org)
  • Some degree of alignment of nanotubes in forests along with substantial entanglement creates a sophisticated conductive network and is responsible for their properties. (nanowerk.com)
  • The findings have been reported in the September 28, 2011 online edition of Applied Physics Letters ( 'Nonlinear electrical properties of carbon nanotube forests' ). (nanowerk.com)
  • These measurements show that room temperature electrical properties of this nanotube network reveal quite substantial nonlinerarities that became more pronounced at sample cooling. (nanowerk.com)
  • In addition, owing to their extraordinary thermal conductivity, mechanical, and electrical properties, carbon nanotubes find applications as additives to various structural materials. (wikipedia.org)
  • Carbon nanotube Optical properties of carbon nanotubes B. Zheng et al. (wikipedia.org)
  • These VANTAs effectively preserve and often accentuate the unique anisotropic properties of individual carbon nanotubes and possess a morphology that may be precisely controlled. (wikipedia.org)
  • June - Gadget invented by Rice University that can sort nanotubes by size and electrical properties. (wikipedia.org)
  • Nanotech
  • These and other applications relay on connectivity of carbon nanotubes in the forest structure' Mikhail Kozlov , a Research Scientist at the NanoTech Institute, University of Texas at Dallas, explains to Nanowerk. (nanowerk.com)
  • single
  • In an intuitive leap, Baughman's group, in collaboration with Ken Atkinson, a textile expert at Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) in Belmont, found a way to make a ribbon of nanotubes in a single motion. (asme.org)
  • The big challenge in this field is to make a connection not just to a single shell of a carbon nanotube," said Fedorov. (ecnmag.com)
  • Until now, no single process was known that would precisely grow carbon nanotubes at any predetermined position on a chip. (eetimes.com)
  • Single-walled nanotubes are likely candidates for miniaturizing electronics. (wikipedia.org)
  • Owing to this limited load transfer between the different layers of MWCNTs, single walled nanotubes (SWCNTs) are more useful structural materials for springs. (wikipedia.org)
  • Single-walled carbon nanotubes can be shortened in a scalable manner using oleum (100% H2SO4 with 3% SO3) and nitric acid. (wikipedia.org)
  • A carbon nanotube field-effect transistor (CNTFET) refers to a field-effect transistor that utilizes a single carbon nanotube or an array of carbon nanotubes as the channel material instead of bulk silicon in the traditional MOSFET structure. (wikipedia.org)
  • These limits can be overcome to some extent and facilitate further scaling down of device dimensions by modifying the channel material in the traditional bulk MOSFET structure with a single carbon nanotube or an array of carbon nanotubes. (wikipedia.org)
  • For example, according to a single-particle tight-binding description of the electronic structure, E g = γ ( 2 a d t ) {\displaystyle E_{g}=\gamma \left({\frac {2a}{d_{t}}}\right)} where γ is the hopping matrix element, and a is the carbon-carbon bond distance. (wikipedia.org)
  • Later that year the team used a composite of graphite and metal catalyst particles (the best yield was from a cobalt and nickel mixture) to synthesize single-walled carbon nanotubes. (wikipedia.org)
  • Single-walled carbon nanotubes can also be synthesized by a thermal plasma method, first invented in 2000 at INRS (Institut national de la recherche scientifique) in Varennes, Canada, by Olivier Smiljanic. (wikipedia.org)
  • Another way to produce single-walled carbon nanotubes with a plasma torch is to use the induction thermal plasma method, implemented in 2005 by groups from the University of Sherbrooke and the National Research Council of Canada. (wikipedia.org)
  • Single wall carbon nanotubes possess a wide range of direct bandgaps matching the solar spectrum, strong photoabsorption, from infrared to ultraviolet, and high carrier mobility and reduced carrier transport scattering, which make themselves ideal photovoltaic material. (wikipedia.org)
  • So, plus strong acid doping, using aligned single wall carbon nanotube film can further improve power conversion efficiency (a record-high power-conversion-efficiency of >11% was achieved by Yeonwoong Jung). (wikipedia.org)
  • Later, nanoindentations with atomic force microscope were performed by several groups to quantitatively measure radial elasticity of multiwalled carbon nanotubes and tapping/contact mode atomic force microscopy was also performed on single-walled carbon nanotubes. (wikipedia.org)
  • Standard single-walled carbon nanotubes can withstand a pressure up to 25 GPa without [plastic/permanent] deformation. (wikipedia.org)
  • citation needed] The bulk modulus of superhard phase nanotubes is 462 to 546 GPa, even higher than that of diamond (420 GPa for single diamond crystal). (wikipedia.org)
  • made
  • Moreover, the nanotube superthreads could conduct and hold electrical charges, suggesting that electronic devices could be directly incorporated into fabrics made of them. (asme.org)
  • Laboratory-made nanotube nanomotors on the other hand are significantly more robust and can operate in diverse environments including varied frequency, temperature, mediums and chemical environments. (wikipedia.org)
  • And a Finnish research group has created a nanotube memory array that's 100,000 times faster than any made before. (fastcompany.com)
  • Nantero chief executive officer Greg Schmergel claimed carbon nanotube memory could be made with conventional CMOS manufacturing, keeping costs low. (computerweekly.com)
  • Because of their tube structure, carbon nanotubes can be made with or without end caps, meaning that without end caps the inside where the drug is held would be more accessible. (wikipedia.org)
  • The first suggestion of using carbon nanotubes as optical antennas is made in the patent application of inventor Robert Crowley filed in January 1997. (wikipedia.org)
  • May - A prototype high-definition 10-centimetre flat screen made using nanotubes was exhibited. (wikipedia.org)
  • monoxide
  • When acetylene is used as the carbon source, carbide formation can occur, which can be prevented by mixing acetylene with carbon monoxide. (nsti.org)
  • Carbon is a ubiquitous element that forms millions of compounds, ranging from simple carbon monoxide to highly complex enzymes. (wikipedia.org)