• 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)
  • 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)
  • 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)
  • substrate
  • The nanotubes, each about 10 nanometers in diameter and 300 micrometers long, grown vertically on the substrate, can pack as closely as one trillion per square inch. (asme.org)
  • Where the aerogel and the nanotubes meet, tubes catch on the aerogel and are pulled from the substrate. (asme.org)
  • Baughman's team then layered several ribbons atop one another in a crosswise pattern and dissolved the aerogel substrate, leaving a membrane or thin sheet of nanotubes held together by atomic forces. (asme.org)
  • The pipes are fabricated as ribbons, hang from a silicon wafer, and are suspended 100 nanometers above a carbon substrate layer. (computerweekly.com)
  • To make it scalable for manufacturing, they also worked toward technologies for isolating and aligning individual carbon nanotubes between the metal terminals on a silicon substrate, and for examining the properties of the resulting structures. (ecnmag.com)
  • e open ends of carbon nanotubes on any desired substrate. (ecnmag.com)
  • One set of MWNT bundles are laid on the substrate and another set of bundles is trenched on top of the underlying nanotube bundles with an air gap in between them. (wikipedia.org)
  • The current technical challenge with this design is the lack of control to place arrays of carbon nanotubes on substrate. (wikipedia.org)
  • In the case of the tip-growth model, hydrocarbon decomposes on the top surface of the metal, carbon diffuses down through the metal, and CNT precipitates out across the metal bottom, pushing the whole metal particle off the substrate, and continues to grow until the metal is fully covered with excess carbon and its catalytic activity ceases. (wikipedia.org)
  • The solar cells consist of a semitransparent thin film of nanotubes conformally coated on a n-type crystalline silicon substrate to create high-density p-n heterojunctions between nanotubes and n-Si to favor charge separation and extract electrons (through n-Si) and holes (through nanotubes). (wikipedia.org)
  • Additionally aligned nanotube film has much smaller void space, and better contact with substrate. (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)
  • silicon
  • The first computer built with carbon nanotubes instead of silicon has been unveiled in California. (huffingtonpost.co.uk)
  • People have been talking about a new era of carbon nanotube electronics moving beyond silicon," said Professor Subhasish Mitra, an electrical engineer and computer scientist, in a statement. (huffingtonpost.co.uk)
  • The technique could facilitate the integration of carbon nanotubes as interconnects in next-generation integrated circuits that use both silicon and carbon components. (ecnmag.com)
  • Until now, however, resistance at the connections between the carbon structures and conventional silicon electronics has been too high to make the devices practical. (ecnmag.com)
  • The nanotubes grow perpendicularly to the edge of the silicon dioxide region. (eetimes.com)
  • Carbon nanotube supported catalyst is a novel supported catalyst, using carbon nanotubes as the support instead of the conventional alumina or silicon support. (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)
  • In theory, carbon nanotubes are also able to conduct heat nearly as well as diamond or sapphire, and because of their miniaturized dimensions, the CNTFET should switch reliably using much less power than a silicon-based device. (wikipedia.org)
  • Thus, some nanotubes have conductivities higher than that of copper, while others behave more like silicon. (wikipedia.org)
  • January - IBM creates 9 nm carbon nanotube transistor that outperforms silicon. (wikipedia.org)
  • composite
  • Hernandez E, Goze C, Bernier P, Rubio A (1998) Elastic properties of C and B x C y N z composite nanotubes. (springer.com)
  • Promising approach to overcome the to date limitations are either to make very tiny local connections that will be needed in future advanced chips or to make carbon metal composite structure that will be compatible with existing microelectronic processes. (wikipedia.org)
  • The project named CONNECT (CarbON Nanotube compositE InterconneCTs) involves the joint efforts of seven European research and industry partners on fabrication techniques and processes to enable reliable Carbon NanoTubes for on-chip interconnects in ULSI microchip production. (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)
  • quantum
  • The group aims to build a nanotube architecture that will exhibit near-superconducting speeds at room temperature, plus the ability to pack devices tighter and control quantum effects. (eetimes.com)
  • Similarly, nanotubes can be doped with impurities to create quantum dots. (eetimes.com)
  • Applied quantum chemistry, specifically, orbital hybridization best describes chemical bonding in nanotubes. (wikipedia.org)
  • A carbon nanotube quantum dot (CNT QD) is a small region of a carbon nanotube in which electrons are confined. (wikipedia.org)
  • 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)
  • electrons
  • When the secondary electrons interact with hydrocarbon precursor molecules introduced into the SEM chamber, carbon is deposited in desired locations. (ecnmag.com)
  • A CNT QD is formed when electrons are confined to a small region within a carbon nanotube. (wikipedia.org)
  • 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)
  • 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)
  • tubes
  • As individual tubes are drawn from a dense thicket of nanotubes (top and middle), they pull away adjoining tubes to create a long, horizontal array. (asme.org)
  • Thanks to the close packing of the tubes and to an attractive force operating at the molecular level, a nanotube breaking away from its base will pull away other tubes. (asme.org)
  • properties
  • Materials scientists have long known that carbon-based molecules can possess extreme properties-after all, diamonds are pure carbon. (asme.org)
  • The various beneficial properties of carbon nanotubes makes them the most attractive material to base such nanomotors on. (wikipedia.org)
  • Carbon nanotubes are the most studied carbon structures due to their outstanding mechanical, electrical, optical, and chemical properties what offer a broad range of possible applications. (springer.com)
  • Cornwell CF, Wille LT (1997) Elastic properties of single-walled nanotubes in compression. (springer.com)
  • Govindjee G, Sackman JL (1999) On the use of continuum mechanics to estimate the properties of nanotubes. (springer.com)
  • Lu JP (1997) Elastic properties of single and multilayered nanotubes. (springer.com)
  • 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)
  • These cylindrical carbon molecules have unusual properties, which are valuable for nanotechnology, electronics, optics and other fields of materials science and technology. (wikipedia.org)
  • 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)
  • 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)
  • molecules
  • To make the altered nanotubes, Dirk M. Guldi of the University of Notre Dame and his colleagues attached molecules of ferrocene to their walls. (scientificamerican.com)
  • 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)
  • 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)
  • graphite
  • But common forms of carbon, such as graphite, are soft rather than strong. (asme.org)
  • At the molecular level, the difference between graphite and carbon nanotubes is similar to that between sheet metal and steel tubing of the same gauge. (asme.org)
  • When they heard of the existence of nanotubes they replaced the metals with graphite to create multi-walled carbon nanotubes. (wikipedia.org)
  • In this method, the aim is to reproduce the conditions prevailing in the arc discharge and laser ablation approaches, but a carbon-containing gas is used instead of graphite vapors to supply the necessary carbon. (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)
  • 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)
  • Unique to the EBID process, the deposited carbon makes a strong, chemically-bonded connection to the ends of the carbon nanotubes, unlike the weakly-coupled physical interface made in traditional techniques based on metal evaporation. (ecnmag.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)
  • structures
  • There are two models that can be used to describe the structures of multi-walled nanotubes. (wikipedia.org)
  • further reported on similar structures formed on carbon fiber paper, also for use in supercapacitor applications. (wikipedia.org)
  • Systems being used currently for drug delivery include dendrimers, polymers, and liposomes, but carbon nanotubes present the opportunity to work with effective structures that have high drug loading capacities and good cell penetration qualities. (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)
  • 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)
  • Chwał M (2014) Non-linear modeling of single-walled carbon nanotubes. (springer.com)
  • Lisi X, Guohao W, Hao Z, Fan Z, Zhide G, Chuan L, Xianzhong Z, Lei Z (2016) Functional long circulating single walled carbon nanotubes for fluorescent/photoacoustic imaging-guided enhanced phototherapy. (springer.com)
  • 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)
  • 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)
  • 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)