Wednesday, December 31, 2008

Top Ten Nanotechnology Patents of 2008

Here is a list of the U.S. nanotechnology patents issued over the past year that appear to me to be the most commercially valuable and/or interesting:

#10 - US Patent 7,460,669 - 2-bit Encoding Using a Single Photon (Toshiba)

This patent is key to quantum cryptography by providing the foundations for multi-bit state encoding of data in individual photons. Developments in integrated optoelectronics in the past decade may begin to make this technology competitive with standard encryption in the next decade.

#9 - US Patent 7,359,888 - Molecular Junction Neural Network (Hewlett-Packard)

Simulation of neural networks are commonplace using software, however this patent teaches a system using molecular junctions to emulate the function of neural networks which has the potential to provide an entirely new type of neuromorphic computing.

#8 - US Patent 7,374,649 - DNA Sorting of Carbon Nanotubes (E.I. du Pont)

One of the critical problems of single walled nanotube processing is the sorting of the nanotubes between metallic and semiconducting types as well as between different diameter tubes. This patent teaches how DNA can be used to solve the problem.

#7 - US Patent 7,321,188 - Carbon Nanotube Yarn Filament for Light Bulb (Hon Hai Precision)

The first commercially successful light bulb built by Thomas Edison was based on carbonized fibers. It was not too long after that that tungsten came along as an improved filament but this patent may put carbon back in play based on carbon nanotube yarns which are suggested to have better efficiency for less power consumption.

#6 - US Patent 7,321,714 - Nanoparticulate Seal for Integrated Circuits (ERS Company)

This patent from Dr. Ephraim Suhir is very basic to an entirely new form of electronics packaging and teaches a lightweight moisture-resistant nanoparticulate material for protecting integrated circuits.

#5 - US Patent 7,468,097 - Hydrogen Production from Greenhouse Gas Saturated Nanotubes (University of North Texas)

This patent seems to have the potential to simultaneously solve 3 major technological problems in one blow - global warming, production of hydrogen for fuel cells, and nanotube mass production.

#4 - US Patent 7,390,477 - Ultrapure Carbon Nanotubes (William Marsh Rice University)

Based on a series of continuations going back to 1997 this patent includes basic claims to high purity (99%) nanotube compositions. Unlike many earlier patents based on the early research of Rice this patent is not limited to the single walled variety of nanotube and may be applicable to multiwall or other nanotube variations.

#3 - US Patent 7,371,457 - Core/Shell Optical Nanoparticles (William Marsh Rice University)

There has been much development in the past few years in metal/dielectric nanoparticles for applications in molecular spectroscopy methods such as SERS. This appears to be the basic patent covering many of these methods with priority going back to 1997.

#2 - US Patent 7,449,133 - Transparent Graphene (Unidym)

For several years there has been a search for an improved material for transparent electrodes in display and touch screen applications due to the brittle nature and expense in manufacturing current materials. Graphene flakes provide a very attractive alternative and this patent seems to be basic to transparent graphene electrodes.

#1 - US Patent 7,443,711 - Nanoscale Memristor (Hewlett-Packard)

While the development of electronics in the last 60 years has been impressive, almost all of the developments have been based on the same basic building blocks - resistors, capacitors, and transistors. This patent is basic to a new fundamental circuit element called a "memristor" which could possibly provide a new avenue of electronics beyond the transistor. Already there are plans by HP to implement memristors in a new form of non-volatile memory which does not require transistors for the memory cells and is thus capable of deep nanoscale resolutions competitive with flash memory.

Tuesday, December 30, 2008

US Patent 7471388 - Tunable nanoparticle resonator

Metal nanoparticles are very useful for molecular analysis techniques such as Surface Enhanced Raman Spectroscopy. This patent from the University of Central Florida teaches using a silicon cantilever as a tuning mechanism to adjust the responsiveness of the metal nanoparticles to different wavelengths. Claim 1 reads:

1. A frequency tunable resonant apparatus comprising:

a top substrate and a bottom substrate separated by a distance;

a nanostructure having a diameter smaller than an excitation wavelength of the nanostructure; and

a movable silicon cantilever in a vicinity of said nanostructure between said top and said bottom substrate, wherein a plasmon resonance of said nanostructure is tuned to several different excitation wavelengths according to a proximity of said movable silicon cantilever to said nanostructure enabling the detection of several species with said nanostructure.


US Patent 7470954 - Nanowell array for nanoparticles

This patent from the Regents of the University of California teaches an array of cells in which magnetic nanoparticles are deposited to achieve a media for high density data storage. Claim 1 reads:

1. A fabricated device comprising:

a photoresist coated-substrate formed with wells through its surface, said wells having gradually sloping walls and an aspect ratio of less than 0.37, and micelles enclosing nanoparticles disposed in said wells.


US Patent 7470473 - Nanocrystal composite laser

Most conventional lasers are limited in their spectral output. However, the use of quantum dot nanocrystals provides a degree of tuning of photoemission based on the nanocrystal size distribution. This patent from M.I.T. teaches a nanocrystal metal oxide composite used for lasing. Claim 1 reads:

1. A laser comprising:

a grating; and

a semiconductor nanocrystal layer disposed on the grating, the layer including a plurality of semiconductor nanocrystals including a Group II-VI compound, the nanocrystals being distributed in a metal oxide matrix.


Monday, December 29, 2008

US Patent 7468332 - Nanolayer electroconductive fabric

This patent teaches some nanomaterials having potential use for "electrotextiles" providing the integration of clothing with electronic systems such as sensors or communication systems. Claim 1 reads:

1. An electrically conductive fabric comprising:

a fabric substrate material; and

at least a first nanolayer of a first substance applied directly onto said fabric substrate material, and a second nanolayer of a second substance applied onto said first nanolayer;

at least one of said first substance and/or second substance comprising a conductive substance selected from the group consisting of nanoparticles, conductive polymer, and a combination of nanoparticles with a conductive polymer;

said second substance being selected from the group consisting of nanoparticles of graphite, metals, conductive metal oxides, and conductive polymers selected from the group consisting of polyaniline, poly(anilinesulfonic acid), polyaniline doped with ligninesulfonic acid, polypyrrole, polypyrrole doped with polystyrenesulfonic acid, polythiophene, poly(ethylenedioxythiophene) doped with polystyrenesulfonic acid; and said conductive metal oxides being selected from the group consisting of conductive titanium dioxide, antimony doped tin oxide, aluminum doped zinc oxide, and zirconium doped zinc oxide.

US Patent 7468315 - Nanowire composite for electronic substrate

Nanosys is a company pioneering new methods of nanoelectronics based on nanowire composites. This is their latest patent detailing one of their manufacturing methods. Claim 1 reads:

1. A process for producing an electronic substrate, comprising:

(a) forming a plurality of nanowires on a first substrate;

(b) depositing a material over at least a portion of the plurality of nanowires to form a nanowire-material composite;

(c) removing the nanowire-material composite from the first substrate;

(d) attaching the nanowire-material composite to a portion of a second substrate such that the nanowires are aligned substantially parallel to each other on a surface of the second substrate;

(e) removing the material from the nanowire-material composite to form on the surface of the substrate the plurality of nanowires aligned substantially parallel to each other on the second substrate; and

(f) forming contacts to said plurality of nanowires to thereby provide electrical connectivity to said nanowires.


Tuesday, December 23, 2008

US Patent 7468221 - Integration of MEMS with microbatteries

This is another in a series of very fundamental patents to a company called Bipolar Technologies which teaches the integration of microbatteries with microelectromechanical devices. Claim 1 reads:

1. In combination, at least one microelectromechanical system and a source of electrical energy internal within the microelectromechanical system comprising a microfabricated microscopic battery having a size congruent with the microelectromechanical system.


US Patent 7468097 - Hydrogen production from greenhouse gas saturated CNTs

Greenhouse gases such as carbon dioxide are often associated with global warming phenomena. Meanwhile, alternative energy systems such as fuel cells are looking for ways to produce hydrogen to solve the problem of future oil shortages. This patent from the University of North Texas teaches a very interesting potential solution for both these problems using carbon nanotubes saturated with a greenhouse gas which is converted to hydrogen for energy usage. Claim 1 reads:

1. An apparatus for generating and storing hydrogen gas from a saturated carbon nanotube having an attached hydrocarbon gas or attached greenhouse gas, comprising:

(a) a vacuum chamber, wherein the vacuum chamber is in fluid communication with a gas inlet port;

(b) a nanotube holding chamber located inside the vacuum chamber and having a first end and a second end, wherein the first end is in fluid communication with the gas inlet port, and the second end is in fluid communication with a gas exit port;

(c) a hydrogen storage chamber in fluid communication with the gas exit port; and

(d) a microwave generator aligned to discharge microwave energy that impinges on the saturated carbon nanotube having an attached hydrocarbon gas or attached greenhouse gas placed in the nanotube holding chamber.


Monday, December 22, 2008

US Patent 7466523 - Nanotube spin valve

Spintronics has found useful applications in magnetic high density memory storage and sensing devices. This patent teaches ballistic transport of spin via a nanotube channel which may improve the efficiency of such applications. Claim 1 reads:

1. A spin valve device comprising:

a ferromagnetic free layer whose magnetization changes in a magnetic signal field,

a ferromagnetic pinned layer whose magnetization remains unchanged in the magnetic signal field,

a single or a plurality of carbon nanotubes reside between said ferromagnetic free layer and said pinned layer, and are in electrical contact with the two, wherein said carbon nanotube each having a substantially cylindrical wall, having a submicron diameter, a length measured in a direction perpendicular to the diameter, and the length being greater than the diameter, wherein the plane of said ferromagnetic pinned layer is parallel to the plane of said free layer, and said carbon nanotubes are vertically aligned and perpendicular to the planes of said pinned and said free layers, and an electrical current passes from one ferromagnetic layer to the other via said carbon nanotubes during the device operation.

US Patent 7466406 - Nanodisk array nanowire assaying

This patent from Northwestern University discloses an interesting modification of nanowires used in SERS in which nanodisk arrays are etched out of the nanowire to serve as substrates for an analyte allowing for tuning of nanowires for analytes of interest. Claim 1 reads:

1. A method of assaying for a presence or a concentration of an analyte or a plurality of analytes in a sample comprising:

a) contacting the sample with a nanowire to create a mixture, wherein the nanowire comprises at least one nanodisk array comprising at least two nanodisks, each nanodisk independently having a thickness of about 20 nm to about 500 nm, and at least one gap of about 2 to about 500 nm;

b) illuminating the mixture with a radiation source; and

c) measuring a signal intensity resulting from the illumination of the mixture, wherein the intensity is correlated to the presence or concentration of the analyte in the sample.


US patent 7466072 - Low FWHM CNTs

Full width at half maximum (FWHM) diffraction is used to characterize carbon nanotubes and provide an indication of the field emission behavior for the nanotubes. This patent from Samsung includes a very basic claim to a low FWHM diffraction carbon nanotube formed via the arc discharge method and combined with glass frit, ethyl cellulose, methyl acrylic acid, and butyl carbitol acetate. Claim 1 reads:

1. A carbon nanotube having a Full-Width at Half-Maximum of X-ray diffraction that is less than or equal to 0.6.

However, it is not entirely clear to me how this is different from data determined by Smalley's group at Rice back in 1998 (see Fig. 6 and section 3.2 of the article "Large-scale purification of single walled carbon nanotubes: process, product, and characterizations" published in Applied Physics A) which seems to disclose a FWHM of 0.1.


Sunday, December 21, 2008

US Patent 7466069 - CNT bridge

In order to better characterize the properties of carbon nanotubes and use the nanotubes in applications such as molecular sensors this patent from Harvard teaches growing a suspended nanotube over an apertured region of a substrate suitable for a flow through sensor. Claim 1 reads:

1. A carbon nanotube device comprising:

a substrate including an aperture extending from a front surface to a back surface of the substrate, with the aperture open only at the front surface and the back surface;

at least one pair of electrically conducting contact pads disposed on a selected one of the front and back substrate surfaces with the conducting contact pads in a given pair of pads being separated from each other by the aperture;

a carbon nanotube catalyst region disposed on top of each of the contact pads in alignment with an edge of the aperture and exposed at the selected substrate surface; and

at least one carbon nanotube extending across the aperture and accessible through the aperture from both the front surface and the back surface of the substrate, each end of the carbon nanotube contacting an exposed catalyst region on a contact pad at the selected substrate surface.


US Patent 7465871- Thermoelectric nanomaterials with small band offset

This patent is based on a collaboration between M.I.T. and Boston College and teaches incorporating semiconductor nanostructures in a host semiconductor formed of a material having a different energy level than the nanostructures to enhance thermal efficiency in applications such as thermoelectric cooling.

1. A thermoelectric nanocomposite semiconductor composition, comprising:

a semiconductor host material, and

a plurality of nano-sized inclusions distributed randomly within said host material, said inclusions being formed of a semiconductor inclusion material, wherein said host material comprises dopants, and wherein the conduction band-edge offset or a valence band-edge offset between said host material and the inclusion material at an interface of the two materials is less than about 5kBT, wherein kB is the Boltzman constant and T is an average temperature of said nanocomposite composition.

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US Patent 7465612 - Nanowire channel FET fabrication with bottom gate

The two basic approaches to incorporating nanowire semiconductor channels in transistor design are 1)nanowire growth directly on the substrate and 2) printing prefabricated nanowires using an inkjet or other printing device. This patent from LG Display teaches a variation of the later approach allowing for improved yield by forming a bottom gate contact prior to the nanowire deposition and source/drain fabrication. Claim 1 reads:

1. A fabricating method of a thin film transistor substrate, the method comprising:

forming a gate electrode on a substrate;

forming a gate insulating film on the gate electrode, the gate insulating film having a groove in an area corresponding to an area where an active layer of a thin film transistor is to be formed;

forming the active layer of the thin film transistor by use of a nanowire in the groove of the gate insulating film; and

forming a source electrode and a drain electrode on the active layer.


Friday, December 19, 2008

US Patent 7465605 - CNT functionalization via partial thermal degradation of polymers

Many electronics companies are focusing on the potential of carbon nanotubes for semiconductor channels or as electrodes. Intel's strategy seems more focused on the thermal properties of CNTs and this patent teaches a functionalization method to ease the incorporation of nanotubes into a polymer composite to be used in heat transport. Claim 1 reads:

1. A method comprising:

growing or depositing a carbon nanotube (NT) array on a substrate;

functionalizing the NT array in situ with a polymer by partial thermal degradation of the polymer to form a NT structure;

characterizing functionalization of the NT structure;

processing the functionalized NT structure according to the characterized functionalization.


US Patent 7465595 - AFM manufacture of quantum dot electronics

This patent from Fujitsu teaches using atomic force microscopes to form quantum dot electronic structures. With high density AFM arrays this type of technology could eventually enable production of quantum computers. Claim 1 reads:

1. A manufacturing method of a quantum device, comprising the steps of:

bringing a tip of an atomic force microscope to which a negative bias is applied into contact with a surface of a semiconductor substrate to form a ring-shaped oxide film on the surface of the semiconductor substrate in an atmosphere containing water;

forming a ring-shaped groove in the surface of the semiconductor substrate by removing the oxide film; and

growing a semiconductor film in the groove.


US Patent 7465519 - CNT/graphite cathode for lithium ion battery

This patent from the Hong Kong University of Science and Technology teaches improved cathodes for lithium-ion batteries with higher capacity, higher reversible efficiency, and much longer cycle life than commercially available graphite cathodes. Claim 1 reads:

1. A lithium ion battery wherein the negative electrode material comprises carbon nanotubes having no dimension greater than 2 μm, and wherein the negative electrode material comprises a mixture of said carbon nanotubes and graphite.


Tuesday, December 16, 2008

US Patent 7465497 - High breakdown voltage nanocomposites

US Patent 7465497

This patent from General Electric teaches high-k dielectrics for breakdown resistant spark plugs having based on coated nanoparticle polymer composites. Claim 1 reads:

1. A composition comprising:

a thermoplastic polymer, wherein the thermoplastic polymer has a glass transition temperature greater than or equal to about C.; and


wherein the nanoparticles comprise a substrate upon which is disposed a coating composition;

wherein the substrate has a different dielectric constant from that of the coating composition;

and wherein the composition has a breakdown resistance of greater than or equal to about 200 volts/micrometer.


US Patent 7465494 - On insulator CNT array

US Patent 7465494

This patent from Boston College teaches enhancing the field emission properties of carbon nanotube films via density control of the nanotube arrays formed on an intermediary non-metallic (e.g. SiO2) layer. Claim 1 reads:

1. A carbon nanotube material comprising an array of substantially linear carbon nanotubes with pre-determined densities that are attached to a catalyst substrate material including a metallic conductive layer deposited on a non-metallic material and a plurality of catalytic transition metal microparticles deposited upon the metallic conductive layer, wherein individual carbon nanotubes are aligned with respect to one another within said array.


US Patent 7465381 - Nanochannel molecular sorting

US Patent 7465381

Microfluidics allows for the sensing and manipulating DNA with a smaller sample size. this patent from the University of New Mexico teaches the next step into nanofluidics by using nanochannels such as carbon nanotubes in sorting individual molecules. Claim 1 reads:

1. A method for separation of molecules in at least one nanochannel comprising:

providing at least one nanochannel having charged nanochannel walls;

providing an electrolyte solution to the at least one nanochannel so that an electrical double layer forms near the charged nanochannel walls;

introducing a mixture of at least two different types of molecules into at least one nanochannel;

allowing electroosmosis through at least one nanochannel to transport at least one of the at least two molecule types within the nanochannel and to separate at least two different types of molecules within the nanochannel.


Sunday, December 14, 2008

US Patent 7463476 - Non-catalytic CNT capacitor fabrication



forming a conductive layer for forming a lower electrode;


forming a dielectric layer on the nanotube array; and

forming an upper electrode on the dielectric layer.


US Patent 7463421 - Image capturing using MEMS

Iridigm Display Corporation (IDC), a pioneer in MEMS based interferometric displays, was acquired by Qualcomm a few years ago. This patent from IDC has some very basic claims to image capturing devices (e.g. cameras, printers) using MEMS filters with early priority going back to May 5, 1994. Claim 1 reads:

1. A system for selecting spectral frequencies of light, comprising:

a tunable filter comprising a MEMS device comprising a movable layer, said MEMS device configured to select a range of spectral frequencies of light; and

a photosensitive device spaced apart from the movable layer, wherein said MEMS device is disposed to direct at least a portion of said selected spectral frequencies onto said photosensitive device.

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Thursday, December 11, 2008

US Patent 7463116 - Complementary MEMS resonators

This patent from Sony teaches a microresonator array configured to balance oscillation forces leading to more stable operation. Claim 1 reads:

1. A micro-resonator comprising:

a plurality of micro-resonant elements having a beam structure facing an input electrode and an output electrode which use a micromechanical oscillation provided on the same substrate, wherein, a micro-resonant element to oscillate in a first phase and a micro-resonant element to oscillate in a second phase that is a reverse phase to the first phase are disposed to be a pair.


US Patent 7462666 - Homogeneous nanofiller dispersion

This patent from GM teaches a method of forming polymer nanocomposites with a more uniform distribution of clay nanoparticles. Claim 1 reads:

1. A method for making a nanocomposite material, the method comprising the steps of:

providing a molten polymeric material in an extruder;

introducing a solution including a nanofiller material and a supercritical fluid into a molten polymeric material; and

causing the supercritical fluid within the solution to substantially instantaneously convert to a gas phase, thereby forming the nanocomposite material having the nanofiller material substantially homogeneously dispersed therein.


Tuesday, December 09, 2008

US Patent 7462499 - ZnO coated CNTs for field emission

Due to the high aspect ratio and electrical properties of carbon nanotubes they have exceptional electron emission behavior useful to flat panel displays and electron beam lithography. This patent from Sharp teaches further improvement in the emission by forming ZnO material regions extending from the carbon nanotube tips. Claim 1 reads:

1. A method for fabricating a nanotube with ZnO asperities, the method comprising:

forming a substrate;

growing carbon nanotubes (CNTs), with a surface, from the substrate;

conformally coating the CNTs with ZnO;

annealing the ZnO-coated CNTs; and,

forming ZnO asperities on the surface of the CNTs in response to the annealing.


US Patent 7462498 - Activation method for CNT field emission

In order to achieve uniform field emission with carbon nanotube deposits it is useful to remove residual material. However, using an adhesive material for such removal can remove too many nanotubes and/or leave additional residue from the adhesive. This patent from Applied Nanotech (formerly Nano-Proprietary) teaches a simple method for flatten CNT films without such problems by using a non-adhesive material. Claim 1 reads:

1. A method of improved electron field emission from a field emission cathode containing a layer of carbon nanotubes, said method comprising the steps of:

depositing said CNT layer onto a substrate;

pressing a non-adhesive material in contact with the CNT layer; and

removing the non-adhesive material from contact with the CNT layer.


US Patent 7462419 - Microscopic battery with ion transmitting electrolyte

This patent from Bipolar Technologies has some early priority (3/10/1998) and teaches an electrolytic microfabricated battery structure. Claim 1 reads:

1. A microfabricated battery comprising:

a system for internal storage of electricity comprising reactants,

the microfabricated battery having a volumetric size which is microscopic including a micrometer footprint substantially less than 20 cm2 and congruent with a microelectronic circuit accommodating integration with the circuit to provide long term stored power and to materially limit power losses,

the microfabricated battery comprising a body of material having:

a first microfabricated electrode of chemically reactant material,

a second microfabricated electrode spaced from the first electrode and

a microscopic amount of internal ion-transmitting electrolyte which restricts electronic current flow and accommodates reactions at the electrodes contained within an internal microfabricated space in the body accessible to both electrodes.


Monday, December 08, 2008

US Patent 7460669 - 2-bit encoding using single photon

This patent from Toshiba has a fairly early priority date (Oct. 25, 2000) and seems to present some very basic claims to using a single photon to encode multi-bit data states which may be important to future quantum computing. Claim 1 reads:

1. A method of encoding at least two bits of information on a single photon, the method comprising the step of setting at least two parameters of the photon to respectively correspond to the at least two bits of information such that the at least two bits of information are encoded onto the photon using the at least two parameters.


US Patent 7460490 - Micromechanical displays with rear surface light guide

This patent from Pixtronix teaches a micromechanical display having improved luminous efficiency over typical backlight approaches. Claim 1 reads:

1. A display apparatus comprising:

a light guide;

a substrate having a front surface facing an intended viewer and a rear surface facing the light guide, wherein the substrate is separated from the light guide by a gap; and

an array of MEMS-based light modulators formed on the rear surface of the substrate.


US Patent 7460224 - Arrays of nanostructures for SERS

This patent from Opto Trace Technologies is based on a finding that SERS, which is a highly sensitive a molecular detection mechanism, can be improved by arranging both active nanostructured surfaces formed using noble metals and inactive nanostructured surfaces formed using dielectric materials side be side. Claim 1 reads:

1. A sensing device for surface-enhanced Raman spectroscopy (SERS), comprising:

a substrate;

a plurality of nano structures on the substrate, wherein each of the nano structures is a three dimensional object having at least one dimension smaller than 300 nanometer, and at least one of the nano structures comprises an active SERS nano surface and an inactive SERS nano surface in proximity to the active nano SERS surface; and

an adsorption layer on the active SERS nano surface or the inactive SERS nano surface.


Saturday, December 06, 2008

US Patent 7459933 - Pattern recognition using mem-resistor crossbar array

Earlier this year researchers at Hewlett-Packard announced a physical realization of a nanoscale memristor as a fundamentally new circuit element originally theorized by UC Berkeley professor Leon Chua in 1971. One of the benefits of memristors is that they can bridge the gap between software and hardware in the areas of image analysis and pattern recognition. This is one of my basic patent to using hysteretic resistance materials similar to that found for memristors in pattern recognition. I was graciously invited to speak at a symposium on memristors on some of my proposed applications along with Leon Chua and some of the senior scientists at HP. Video of the symposium is available on Youtube here (my portion starts at 1:25:25).

Claims 1 and 18 read:

1. A method comprising:

storing two-dimensional binary data in the form of high or low resistance states into a crossbar array with a programmable material layer; and

transforming the two-dimensional binary data into one-dimensional analog data via the crossbar array wherein the stored two-dimensional binary data is image data received from a sensing array.

18. A method comprising:


transforming the two-dimensional binary data into one-dimensional analog data via the crossbar array; and

using the one-dimensional analog data for pattern comparison, pattern location, or pattern tracking.

US Patent 7459682 - Nanowire array spin-polarized electron source

One variety of nanoscale detection devices is spin polarized scanning probe microscopy which uses the spin of electrons emitted from a sharp tip to characterize magnetic phenomena on the nanoscale. However continuous emission is difficult at room temperature. This patent from Hon Hai Precision and Tsinghua University teaches using III-V nanowire arrays to achieve such microscopy at room temperature. Claim 1 reads:

1. A spin-polarized electron source, comprising:

a cathode;

a one-dimensional nanostructure comprised of a compound semiconductor with local polarized gap states, the one-dimensional nanostructure including a first end portion electrically connected with the cathode and a second end portion directed away from the cathode, the second end portion of the one-dimensional nanostructure functioning as a polarized electron emission tip and being configured for emitting a spin-polarized electron current/beam under an effect of selectably one of a magnetic field induction and a circularly polarized light beam excitation when a predetermined negative bias voltage is applied to the cathode.

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Thursday, December 04, 2008

US Patent 7,459,627 - CNT shielding for coaxial cable

This patent from Hon Hai Precision and Tsinghua University is similar to an earlier patent (US Patent 7449631) and extends the scope of protection to using carbon nanotubes as electromagnetic shielding for coaxial cables.

1. A coaxial cable comprising:

at least one conducting wire;

at least one insulating layer, each insulating layer being respectively coated on a corresponding conducting wire;

at least one shielding layer surrounding the at least one insulating layer, each shielding layer comprises one or more carbon nanotube films; and

a sheath wrapping the at least one shielding layer.

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US Patent 7459673 - Atomtronic switch with neutral atoms

Most engineers and scientists are familiar with the basic concepts of electronics and photonics which respectively attempt to create amplifying and switching circuits using electron transport and photon transport. Atomtronics is a more obscure way to create circuitry providing effects similar to superconductors and which may provide a path to quantum computing. Some early work in this area was done by Don Eigler of IBM and researchers at Hitachi and Stanford in atomic chain networks. This patent from Japan Science and Technology Agency teaches an atomtronic switch formed using neutral atoms. Claim 1 reads:

1. An atomic device using a neutral particle which is a neutral atom or a neutral molecule, comprising:

a first pair of electrodes provided at positions on a substrate with a trapping position disposed therebetween, and along a first axis passing through the trapping position, the trapping position being defined at a predetermined position on the substrate, and

a second pair of electrodes provided at positions on the substrate with the trapping position disposed therebetween, and along a second axis provided at a predetermined angle to the first axis and passing through the trapping position,

wherein the atomic device switches between a first state and a second state alternately to trap a neutral particle at the trapping position, one of the electrodes of the first pair of electrodes being set at a positive potential with respect to a reference potential and the other electrode being set at a negative potential in the first state, one of the electrodes of the second pair of electrodes being set at a positive potential with respect to the reference potential and the other electrode being set at a negative potential in the second state.


US Patent 7459312 - Cleaning of CNT sensors using light

This patent from Stanford University teaches a method of using light to remove molecules from a carbon nanotube sensor to facilitate repeated use. Claim 1 reads:

1. A method for using a carbon nanotube device including a carbon nanotube, the method comprising:

using a light source to direct light at the carbon nanotube and to desorb molecules from the carbon nanotube;

detecting a change in an electrical characteristic of the carbon nanotube; and

using the detected change to detect that the molecules have been desorbed from the carbon nanotube.


Tuesday, December 02, 2008

US Patent 7459324 - Photonic metal nanoparticle

Photonics is analogous to electronics except instead of using circuits for transporting electrons the circuits of photonic devices transport particles of light. This patent from U.S. Naval Research Labs teaches an optical amplification device based on metal nanoparticles which seem to be a type of optical transistor. Claim 1 reads:

1. A method, comprising:

providing a substrate having a semiconductor layer over an insulator layer;

operatively coupling said substrate to a photonic bandgap structure having at least one period, wherein said photonic bandgap structure is adapted to receive and output light along a predetermined path; and

operatively coupling said photonic bandgap structure and said substrate to a metal nanoparticle structure comprising at least three metal nanoparticles having spherical shapes of different radii, wherein said at least three metal nanoparticles are adapted to receive and amplify light rays and output amplified light.


US Patent 7459137 - Solvent-free CNT functionalization

Due to molecular forces carbon nanotubes often bundle together making it necessary to include a solvent when functionalizing the nanoubes for applications such as biosensors. However, the requirement for solvent places a constraint on the type of environments and chemical reactions permitted for the functionalization. This patent from Rice University teaches methods of solvent-free functionalization of carbon nanotubes to expand the range of situations in which functionalization can occur. Claim 1 reads:

1. A method for functionalizing carbon nanotubes comprising:

a) selecting a plurality of carbon nanotubes; and

b) reacting said plurality of carbon nanotubes at the sidewall carbon atoms with an organic functionalizing agent in the absence of a solvent.

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US Patent 7459121- Nanotube membrane fabrication

Buckypaper is a membrane material formed from carbon nanotubes having potential applications as an emission material for displays and in body armor but early fabrication methods have been discontinuous and produce only small quantities. This patent from Florida State University teaches a new manufacturing method to produce larger size buckypaper with a continuous fabrication procedure. Claim 1 reads:

1. A method for the continuous production of a network of nanotubes or other nanoscale fibers comprising:

making a suspension of nanoscale fibers dispersed in a liquid medium; and

filtering the suspension by moving a filter membrane through the suspension, into transitory contact with a filter element, such that the nanoscale fibers are deposited directly on the filter membrane as the fluid medium flows through the filter membrane, thereby forming a continuous membrane of the nanoscale fibers.