University of California

Marvin Lou Cohen

Alexander K Zettl

Steven G Louie

Alex Zettl

Vincent Henry Crespi

John P Cumings

Steven Gwon Sheng Louie

Jeffrey C Grossman

Charles Piskoti

Eugene E Haller

William L Hansen

Michel Cote

The invention relates to a method for forming a telescoped multiwall nanotube. Such a telescoped multiwall nanotube may find use as a linear or rotational bearing in microelectromechanical systems or may find use as a constant force nanospring. In the method of the invention, a multiwall nanotube is affixed to a solid, conducting substrate at one end. The tip of the free end of the multiwall nanotube is then removed, revealing the intact end of the inner wall. A nanomanipulator is then attached to the intact end, and the intact, core segments of the multiwall nanotube are partially extracted, thereby telescoping out a segment of nanotube.

Telescoped multiwall nanotube and manufacture thereof

A solid phase or form of carbon is based on fullerenes with thirty six carbon atoms (C). The Cstructure with Dsymmetry is one of the two most energetically favorable, and is conducive to forming a periodic system. The lowest energy crystal is a highly bonded network of hexagonal planes of Csubunits with AB stacking. The Csolid is not a purely van der Waals solid, but has covalent-like bonding, leading to a solid with enhanced structural rigidity. The solid Cmaterial is made by synthesizing and selecting out Cfullerenes in relatively large quantities. A Crich fullerene soot is produced in a helium environment arc discharge chamber by operating at an optimum helium pressure (400 torr). The Cis separated from the soot by a two step process. The soot is first treated with a first solvent, e.g. toluene, to remove the higher order fullerenes but leave the C. The soot is then treated with a second solvent, e.g. pyridine, which is more polarizable than the first solvent used for the larger fullerenes. The second solvent extracts the Cfrom the soot. Thin films and powders can then be produced from the extracted C. Other materials are based on Cfullerenes, providing for different properties.

Carbon based thirty six atom spheres

The present invention comprises a new nanoscale metal-semiconductor, semiconductor-semiconductor, or metal-metal junction, designed by introducing topological or chemical defects in the atomic structure of the nanotube. Nanotubes comprising adjacent sections having differing electrical properties are described. These nanotubes can be constructed from combinations of carbon, boron, nitrogen and other elements. The nanotube can be designed having different indices on either side of a junction point in a continuous tube so that the electrical properties on either side of the junction vary in a useful fashion. For example, the inventive nanotube may be electrically conducting on one side of a junction and semiconducting on the other side. An example of a semiconductor-metal junction is a Schottky barrier. Alternatively, the nanotube may exhibit different semiconductor properties on either side of the junction. Nanotubes containing heterojunctions, Schottky barriers, and metal-metal junctions are useful for microcircuitry.

Nanotube junctions

The invention provides crystalline nanoscale particles and tubes made from a variety of stoichiometries of B,C,N,where x, y, and z indicate a relative amount of each element compared to the others and where no more than one of x, y, or z are zero for a single stoichiometry. The nanotubes and nanoparticles are useful as miniature electronic components, such as wires, coils, schotky barriers, diodes, etc. The nanotubes and nanoparticles are also useful as coating that will protect an item from detection by electromagnetic monitoring techniques like radar. The nanotubes and nanoparticles are additionally useful for their mechanical properties, being comparable in strength and stiffness to the best graphite fibers or carbon nanotubes. The inventive nanoparticles are useful in lubricants and composites.

BX CY NZ nanotubes and nanoparticles

The present invention is an apparatus and method for producing nano-scale tubes and particles. The apparatus comprises novel electrodes for use in arc discharge techniques. The electrodes have interior conduits for delivery and withdrawal of material from the arc region where product is formed. In one embodiment, the anode is optionally made from more than one material and is termed a compound anode. The materials used in the compound anode assist in the reaction that forms product in the arc region of the apparatus. The materials assist either by providing reaction ingredients, catalyst, or affecting the reaction kinetics. Among other uses, the inventive apparatus is used to produce nanotubes and nanoparticles having a variety of electrical and mechanical properties.

Method for making nanotubes and nanoparticles

A novel field emitter material, field emission electron source, and commercially feasible fabrication method is described. The inventive field emission electron source produces reliable electron currents of up to 400 mA/cm.sup.2 at 200 volts. The emitter is robust and the current it produces is not sensitive to variability of vacuum or the distance between the emitter tip and the cathode. The novel emitter has a sharp turn-on near 100 volts.

Field emission electron source

Novel metallic forms of planar carbon are described, as well as methods of designing and making them. Nonhexagonal arrangements of carbon are introduced into a graphite carbon network essentially without destroying the planar structure. Specifically a form of carbon comprising primarily pentagons and heptagons, and having a large density of states at the Fermi level is described. Other arrangements of pentagons and heptagons that include some hexagons, and structures incorporating squares and octagons are additionally disclosed. Reducing the bond angle symmetry associated with a hexagonal arrangement of carbons increases the likelihood that the carbon material will have a metallic electron structure.

Metallic carbon materials

Novel crystalline .alpha. (silicon nitride-like)-carbon nitride and .beta. (silicon nitride-like)-carbon nitride are formed by sputtering carbon in the presence of a nitrogen atmosphere onto a single crystal germanium or silicon, respectively, substrate.

Growing community of inventors

Berkeley, CA, United States of America

Marvin Lou Cohen