2001-Nanotubes-HarwellBlankenship - Carbon Nanotubes Carbon...

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Unformatted text preview: Carbon Nanotubes Carbon Zach Blankenship, Jeff Harwell, Tony Mondejar Today's Presentation Today's Introduction What is a Nanotube History of Nanotube Research Nanotube Structure and Properties Applications of Nanotubes Conclusion Introduction Introduction Why are we interested in Nanotube development? What is a Nanotube? History of the Nanotube? How was it discovered…(who, where and when)? What are different kinds of Nanotubes? What are some properties of a Nanotube? What is Nanotechnology? Applications of Nanotechnology? Chronological Milestones Chronological 1985 Researchers discover soccer ball shaped molecule created by linking together 60 or more carbon atoms. It was later named after R. Buckmister Fuller (buckyballs). 1991 Observation and identification of nanotubes in fullerene soot by Sumio Iijima. 1992 Predictions of metallic/insulating properties. 1993 Synthesis of single-walled nanotubes. Chronological Milestones Chronological 1996 Measurement of individual multiwalled tubes. 1996 Individual nanotube used as an AFM tip. 1996 Production of bulk, monodisperse 1.4 nm SWNTs. 1997 Observation of single-electron effects in individual SWNTs and bundles. Single Walled Nanotube Buckyballs inside a SWNT Buckyballs Properties of Fullerene Nanotubes Nanotubes Pure form of Carbon Structure Conductivity Tensile Strength Elasticity Carbon Nanotubes Carbon Forms of Carbon mmptdpublic.jsc.nasa.gov/jscnano/ (Photo courtesy of Dan Colbert, Rice University) Schematic of Nanotube Structure Structure d2=((n2 + m2 + nm)1/2)0.0783 http://www.pa.msu.edu/~adamsth3/nanotube/properties.html Fundamental Gap Fundamental MWNT Conductance vs. Depth MWNT (Go being the conductance quantum 1/13 kohm). http://www.gtri.gatech.edu/res-news/BALANCE.html Tensile Strength of Engineering Materials Materials Gpa, log scale Amazingly Flexible Tubes Amazingly Carbon Nanotubes and Related Carbon Structures, Harris, p197 Structures The "…force unravels the tube as a knitter would unravel the sleeve of a sweater." (Yakobson & Smalley, 1997) Smalley, (Yakobson & Smalley, 1997) (Yakobson The table below gives a comparison of the magnitude of elastic modulus between substances. Material Diamond Silicon Iron Low Alloy Steels Nylon Silicon Carbide (SiC) Carbon Nanotubes Modulus (GPa) 1000 107 196 200-207 3-3.4 450 approx. 630 (Cornell, 1996) The top picture shows a bent nanotube. The bottom picture shows the same nanotube after release from the matrix. From: Ebbesen (ed.), Carbon Nanotubes: Preparation and Properties, Carbon CRC Press, Boca Raton (1997). Current State of the Research Current A Few Working Applications – Polymer Reinforcement – Electron Guns – Scanning Probe Microscope Tips A Lot of Hype and Theoretical Work – Electronic Circuit Elements – Artificial Nanostructures Polymer Reinforcement Polymer Carbon Nanotubes and Related Structures, Harris, p206 Electron Guns Electron Nanoscale pointed conductors used as electron field emitters Sharp Nanotube Points Make Them Ideal as Electron Guns One application of Electron Guns is in Field Emission Displays – Electrons Emitted from Source Exciting a Phosphor Nanotube in a Field Emission Display Display Carbon Nanotubes and Related Structures, Harris, p150 Scanning Probe Microscope Tips Tips Large, Blunt Conventional Tip Limit Microscope Resolution Sharp Point of Nanotube Provides for High Resolution Imaging – Used as Tips for Atomic Force Microscopy – Electrical Conductivity Allows for Use In Scanning Tunneling Microscopy A New Kind of Pencil New Carbon Nanotubes and Related Structures, Harris, p 209 Nanotubes as Circuit Elements Elements Nanotubes Conductivity is Determined by Chirality and Environment – Semiconducting – Conducting – Insulating Testing A Nanotube For Electrical Properties Electrical Carbon Nanotubes and Related Structures, Harris, p 128 Nanotube Field Effect Transistor Transistor Semiconducting SWNT Placed Between Two Electrodes Appling Voltage To Gate Electrode Changes SWNT from Conducting the Insulating Carbon Nanotubes and Related Structures, Harris, p133 Nanostructures Nanostructures Looks Looks Cool. Can We Build It? It? Carbon Nanotubes and Related Structures, Harris, p 268 In Conclusion In Nanoscale Tubes Made From Carbon Hexagons Exceptional Physical Properties – Semiconducting, Conducting or Insulating – High Strength Field of Research is Only 9 Years Old Best and Most Innovative is Yet to Come ...
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