Patents by Inventor Alexander Karlwalter Zettl
Alexander Karlwalter Zettl has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6835952Abstract: 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.Type: GrantFiled: March 21, 2003Date of Patent: December 28, 2004Assignee: The Regents of the University of CaliforniaInventors: Vincent Henry Crespi, Marvin Lou Cohen, Steven Gwon Sheng Louie, Alexander Karlwalter Zettl
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Publication number: 20040004212Abstract: 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.Type: ApplicationFiled: March 21, 2003Publication date: January 8, 2004Inventors: Vincent Henry Crespi, Marvin Lou Cohen, Steven Gwon Sheng Louie, Alexander Karlwalter Zettl
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Patent number: 6538262Abstract: 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.Type: GrantFiled: January 31, 1997Date of Patent: March 25, 2003Assignee: The Regents of the University of CaliforniaInventors: Vincent Henry Crespi, Marvin Lou Cohen, Steven Gwon Sheng Louie, Alexander Karlwalter Zettl
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Publication number: 20010023021Abstract: The invention provides crystalline nanoscale particles and tubes made from a variety of stoichiometries of BxCYNz 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.Type: ApplicationFiled: April 30, 2001Publication date: September 20, 2001Inventors: Marvin Lou Cohen, Alexander Karlwalter Zettl
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Patent number: 6231980Abstract: The invention provides crystalline nanoscale particles and tubes made from a variety of stoichiometries of BxCyNz 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.Type: GrantFiled: November 25, 1997Date of Patent: May 15, 2001Assignee: The Regents of the University of CaliforniaInventors: Marvin Lou Cohen, Alexander Karlwalter Zettl
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Patent number: 6063243Abstract: 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.Type: GrantFiled: November 25, 1997Date of Patent: May 16, 2000Assignee: The Regents of the Univeristy of CaliforniaInventors: Alexander Karlwalter Zettl, Marvin Lou Cohen
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Patent number: 6057637Abstract: 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.Type: GrantFiled: June 27, 1997Date of Patent: May 2, 2000Assignee: The Regents of the University of CaliforniaInventors: Alexander Karlwalter Zettl, Marvin Lou Cohen
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Patent number: 5993697Abstract: 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.Type: GrantFiled: May 14, 1996Date of Patent: November 30, 1999Assignee: The Regents of the University of CaliforniaInventors: Marvin Lou Cohen, Vincent Henry Crespi, Steven Gwon Sheng Louie, Alexander Karlwalter Zettl