Car bo n Na no-t ube s: An Ov er view BY ARUNDUBEY ROLL NO. 0905EC ELEX. & COMM. DPTT. I. T. M., GWALIOR

Transcription

1 Car bo n Na no-t ube s: An Ov er view BY ARUNDUBEY ROLL NO. 0905EC ELEX. & COMM. DPTT. I. T. M., GWALIOR

2 Pre se nta tion O ve rvie w Definition History Properties Current Application Manufacturing Techniques Future application References

3 Defin itio n: Ca rb on Na notu be s Single-wall carbon nanotubes are a new form of carbon made by rolling up a single graphite sheet to a narrow but long tube closed at both sides by fullerene-like end caps. However, their attraction lies not only in the beauty of their molecular structures: through intentional alteration of their physical and chemical properties fullerenes exhibit an extremely wide range of interesting and potentially useful properties.

4 SCHEMETIC VIEW OF CNTs

5 INTRODUCTION Carbon Nanotubes: Tiny tubes about 10,000 times thinner than a human hair consist of rolled up sheets of carbon hexagons. Discovered in 1991 by researchers at NEC, they have the potential for use as minuscule wires or in ultra small electronic devices. To build those devices, scientists must be able to manipulate the Nanotubes in a controlled way. IBM researchers using an atomic force microscope (AFM), an instrument whose tip can apply accurately measured forces to atoms and molecules, have recently devised a means of changing a nanotube's position, shape and orientation, as well as cutting it

6 Imp ortan t H isto ry 1991 Discovery of multi-wall carbon nanotubes by S. Iijima 1992 Conductivity of carbon nanotubes J. W. Mintmire, B. I. Dunlap and C. T. White 1993 Structural rigidity of carbon nanotubes G. Overney, W. Zhong, and D. Tománek 1993 Synthesis of single-wall nanotubes by S Iijima and T Ichihashi 1995 Nanotubes as field emitters By A.G. Rinzler, J.H. Hafner, P. Nikolaev, L. Lou, S.G. Kim, D. Tománek, P. Nordlander, D.T. Colbert, and R.E. Smalley 1997 Hydrogen storage in nanotubes A C Dillon, K M Jones, T A Bekkendahl, C H Kiang, D S Bethune and M J Heben 1998 Synthesis of nanotube peapods B.W. Smith, M. Monthioux, and D.E. Luzzi 2000 Thermal conductivity of nanotubes Savas Berber, Young-Kyun Kwon, and David Tománek 2001 Integration of carbon nanotubes for logic circuits P.C. Collins, M.S. Arnold, and P. Avouris 2001 Intrinsic superconductivity of carbon nanotubes M. Kociak, A. Yu. Kasumov, S. Guéron, B. Reulet, I. I. Khodos, Yu. B. Gorbatov, V. T. Volkov, L. Vaccarini, and H. Bouchiat

7 Pro perties Metallic conductivity (e.g. the salts A3C60 (A=alkali metals)) Superconductivity with Tc's of up to 33K (e.g. the salts A3C60 (A=alkali metals)) Ferromagnetism (in (TDAE)C60 - without the presence of d-electrons) Non-linear optical activity Polymerization to form a variety of 1-, 2-, and 3D polymer structures

8 Pro perties (2 ) Nanotubes can be either electrically conductive or semiconductive, depending on their helicity. 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. Current length limits are about one millimeter.

9 HOW IT WORKS? Vander Waals forces: Attractive forces among atoms and molecules hold Nanotubes firmly against the surfaces they are placed on. The Vander Waals interaction between the Nanotubes and the surfaces on which they rest is itself strong enough to change the shape of Nanotubes. In general, they tend to adapt to the shape of the surface on which they sit by bending and becoming slightly squashed. Those changes can cause the properties of Nanotubes on surfaces to differ from those of perfect Nanotubes, which are straight and have circular cross-sections. This raises the possibility of tailoring. Nanotubes' properties by intentionally changing their shapes.

10 Curre nt A pplica tio ns Carbon Nano-tubes are extending our ability to fabricate devices such as: Molecular probes Pipes Wires Bearings Springs Gears Pumps

11 Ma nufa ctu ring Te chniqu es Evaporation of solid carbon in arc discharge, Laser ablation, Catalytic chemical vapor deposition of carbon containing gases, Catalytic decomposition of fullerenes.

12 Futu re A pplic atio ns Molecular transistors. Field emitters. Building blocks for bottom-up electronics. Smaller, lighter weight components for next generation spacecraft. Enable large quantities of hydrogen to be stored in small low pressure tanks. Space elevator, Instead of blasting off for the heavens astronauts could reach the ISS as easily as they would a department store: Next floor, LEO, watch your step please!

13 Na notu be F un! You can see animations of virtual nanotubes by following these links: Then select Animation Gallery Also You can create your own virtual SWNT at:

14 Refe re nc es Localized and Delocalized Electronic States in Single-Wall Carbon Nanotubes T. Pichler, M. Knupfer, M. S. Golden, J. Fink, A. Rinzler and R. E. Smalley Phys. Rev. Lett. 80, 4729 (1998) Dr. Sander Tans and Prof. Dr. Cees Dekker of the section Quantum Transport at TU Delft,

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