Thursday, May 31, 2007

US Patent 7225082 - Nanowire barcodes

While one of the common applications of quantum dots is in biomarker applications other nanoparticles may also be applied to this area. This patent from Oxonica discloses the use of segmented superparamagnetic nanowires that function as a barcode identification. Claim 20 reads:

20. A freestanding particle comprising 2 to 50 segments, wherein the particle length is from 20 nm to 50 microns, and the particle width is from 5 nm to 50 microns, and wherein at least one of said segments is comprised of a superparamagnetic compound.


Wednesday, May 30, 2007

US 7224039 - Diamond nanoparticle dielectric

Continuation of Moore's law (related to the exponential increase in transistor density of electronics over time) has required a search for new dielectric materials. Intel has introduced hafnium based high-K dielectric which reduce current leakage and allow for smaller insulation thicknesses. This patent from a company called International Technology goes in the other direction and proposes a low-K dielectric that are more immune to parasitic capacitance effects and which are formed using a polymer composite that includes diamond or diamond-like nanoparticles. Claim 6 reads:

6. A dielectric material suitable for use as a semiconductor interlayer dielectric, comprising an admixture of low dielectric polymer with nanoelements, wherein the nanoelements comprise one or more of the nanoelements selected from the group consisting of diamond nanoparticles, diamond nanorods, silicon carbide nanoparticles and silicon carbide nanorods, and wherein the nanoparticles have a largest dimension that is less than approximately 50 nanometers.

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US Patent 7223474 - Porphyrin nanotube/metal nanorod composite

This patent from Sandia teaches a nanostructure formed from porphyrrin which encapsulates nanorods and which has an interesting property of converting from a tubular to a rodlike structure upon irradiation. Claim 1 reads:

1. A metal nanostructure, comprising: a porphyrin nanotube with a hollow interior, the porphyrin nanotube having an outer surface; and a metal nanorod within the hollow interior, the metal nanorod having a first end and a second end.


Tuesday, May 29, 2007

US Patent 7223444 - Electrostatic nanoimprint stamp

Nanoimprint lithography is another nanolithography process which is being promoted by a variety of companies such as Hewlett-Packard and which has some promise of parallel processing capabilities which will be necessary for mass production. This patent from a company called QuNanoAB proposes an interesting variant on nanoimprinting which uses a nanoimprint mold to create an electrostatic latent image (as in photocopying) on a substrate. The electrostatic pattern then attracts molecules or nanoparticles to the substrate. This method seems to have some advantages over other nanoimprint techniques since the nanoimprint stamp does not need to contact the material being patterned and thus may have a longer life expectancy since there is less potential for soiling or wear. Claim 1 reads:

1. A method comprising the steps of: forming one or more electrically-charged regions of predetermined shape on an insulating surface of a solid first material by contacting portions of said surface corresponding to said one or more regions with a solid material of a tool so as to transfer electric charge from said tool to said surface; and permitting particles of a second material to flow in a vicinity of said one or more electrically-charged regions, to interact with said one or more electrically-charged regions.

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US Patent 7223438 - DPN patterning of magnetic nanoparticles

Nanoink is a company that is exploiting a new lithography process called Dip Pen Nanolithography (DPN) invented at Northwestern University and which uses a water meniscus to transfer material from an atomic force microscope tip to a substrate. This patent appears fundamental to the use of DPN in patterning magnetic nanostructures which is useful to a variety of sensor and high density memory applications. Claim 1 reads:

1. A method of forming a magnetic nanostructure comprising: depositing a magnetic nanostructure precursor on a substrate from a nanoscopic tip; and converting the precursor to form the magnetic nanostructure on the substrate.

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Monday, May 28, 2007

US Patent 7220971 - Nanotube field emitters used in biological processing

Irradiation of biological cells is used in analyzing the radiation risks in cancer therapy. This patent from the University of North Carolina teaches using nanotubes as electron emitters to provide selective irradiation of cells. Claim 1 reads:

1. A method for selectively irradiating target biological cells, the method comprising: (a) providing a plurality of individually controllable electron field emitters; (b) providing an electrode operable to extract electrons from the electron field emitters; (c) determining target biological cells for irradiation; (d) identifying locations of the determined target biological cells; and (e) individually controlling electron extraction from each of the electron field emitters to selectively irradiate the identified locations for irradiating the determined target biological cells.

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US Patent 7220346 - Nanowire fabrication using stepped surface

One of the goals of nanowire fabrication is to increase the length to diameter ratio so that individual nanowires can be used to form connections over greater distances. This patent from the University of California used stepped surfaces of a substrate to assist in forming high aspect ratio nanowires. Claim 1 reads:

1. A method for preparing metallic nanometer scale wires comprising the steps of electrodepositing a metal at a step edge present on a stepped surface to form a wire, and removing the wire off of the stepped surface.

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Thursday, May 24, 2007

US Patent 7220310 - Nanopropeller

This patent claims yet another new type of nanostructure-a nanopropeller. The nanopropeller is taught to be useful in nanofluidic flow control and for improved AFM tips. Claim 1 reads:

1. A nanoscale junction array, comprising: a. an elongated nanowire; and b. a plurality of elongated nanobelts, each having a proximal end and an opposite distal end, the proximal end of each nanobelt being attached to a different location on the nanowire, each nanobelt extending radially away from the nanowire.

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Wednesday, May 23, 2007

US Patent 7220159 - E-beam convergence in nanotube field emitter

An early commercialization area for carbon nanotubes is field emission displays. Substantial patenting has already been done by Samsung, Canon, Nanoproprietary and other companies in this area and continued efforts look toward further applications of nanotube field emission for microwave electronics and massively parallel e-beam lithography. This patent focuses on a manufacturing method used to form an integrated converging mechanism for nanotube generated focused electron beams. Claim 1 reads:

1. A manufacturing method for a converging-type cathode of a field-emission display, comprising the following steps in the order named: a) providing a substrate of the cathode; b) forming a first electrode layer on the substrate; c) forming a second electrode layer composed of a plurality of electron emission sources on the first electrode layer; d) forming a third electrode layer directly on the first electrode layer, the third electrode encircling each electron emission source of the second electrode layer and having a height higher than that of the second electrode layer; e) sintering the first, second and third electrode layers on the substrate.

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Friday, May 18, 2007

US Patent 7218004 - Fusing nanowires using crystal growth

Individually nanowires can have very useful electrical characteristics emerging from ballistic transport, quantum confinement, etc. However, when the nanowires are used in a clustered array the gaps between individual nanowires can reduce such usefulness. This patent from HP teaches a method that fuses nanowires so that clustered arrays of nanowires can maintain the characteristics of individual nanowires. Claim 1 reads:

1. A nanowire interconnection system comprising: means for applying nanowires on a surface of a substrate in a cluster; a solution having a controllable saturation condition, the solution comprising a crystal precursor solute dissolved in a solvent, the nanowires being immersed in the solution; and means for controlling the saturation condition of the solution, such that new crystal material is grown on a surface of the immersed nanowires to fuse together the nanowires of the cluster.

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Thursday, May 17, 2007

US Patent 7217948 - Quantum ring polarizer

In recent years much work has been done in using molecular beams to grow quantum dots on substrates. Quantum rings are a subspecies of quantum dots in which electrons are confined in ring structures grown on a substrate. This patent teaches fabrication of arrays of elongated arrays as well as newly discovered polarization properties of such arrays.

1. A semiconductor substrate comprised of a first compound semiconductor, and having a surface on which a plurality of quantum rings comprised of a second compound semiconductor different from the first compound semiconductor are provided, wherein each of said quantum rings has an elongated shape with an aspect ratio of 2 or more but 5 or less, and extends in a substantially same direction.


US Patent 7217946 - Nanowire fabrication using current induced overthickness

The desire for nanowire fabrication has led many to seek alternative methods to EUV lithography techniques such as nanoimprint lithography and self assembly. This patent teaches using currents between two electrodes to produce an effect that creates an array of parallel nanowires between the electrodes. Claim 1 reads:

1. Process for manufacturing nanowire structures, characterised in that it comprises: manufacture of a thin semiconductor film (1) extending between a first terminal (4) and a second terminal (5), and passage of a current between the first and the second terminals so as to form at least one continuous overthickness (R1, R2, R3) in the thin semiconductor film by migration of a fraction of the semiconductor material under the action of the current, the continuous overthickness being formed along the direction of the current that passes through the film.


Wednesday, May 16, 2007

US Patent 7217748 - Polymer chain grafted carbon nanocapsule

Carbon nanocapsules are basically onionlike arrangements of hollow carbon spheres with applications in light and heat absorption, electromagnetic shielding, organic light emission, solar energy reception, catalysts, sensors, carbon electrodes in lithium batteries, thermally conductive nanoscale composite materials with special electrical properties, and nanoscale carbon powder for printing. This patent from Industrial Technology Research Institute provides a basic claim to a polymer/nanocapsule composite structure. Claim 1 reads:

1. A polymer-chain-grafted carbon nanocapsule, comprising: a carbon nanocapsule; and at least one kind of polymer chain grafted thereon, forming a polymer-chain-grafted carbon nanocapsule in which the carbon nanocapsule is the core thereof, wherein the polymer-chain-grafted carbon nanocapsule is of the following formula: F(-P)m, in which F is the carbon nanocapsule, P is the polymer chain, and m is the number of the polymer chain.

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US Patent 7217404 - Photoinduced combustion of carbon nanotubes

Several years back an undergraduate student at Rensselaer Polytechnic Institute was taking some flash photographs in a lab and accidentally ignited a clump of single-walled carbon nanotubes (see article at

It appears as if the researchers in the lab filed a patent for the effect which has issued with a fairly broad claim reading:

1. A method of transforming a single-walled carbon nanotube (SWNT) comprising exposing the SWNT to light having a power sufficient to ignite the SWNT, wherein the SWNT is ignited by the light.


Tuesday, May 15, 2007

US Patent 7217374 - Carbon nanotube mesh resistor

This patent from Fuji Xerox proposes improved resistor material formed using carbon nanotubes including cross-linking the nanotubes via a polymerization reaction. Claim 1 reads:

1. A resistance element comprising an electrical resistance body consisting of a patterned carbon nanotube structure having a mesh structure, in which plural carbon nanotubes are cross-linked to one another through cross-linked sites.

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US Patent 7216792 - DNA electronics using R-loop bonding of nanoparticle defines an R-loop as a single stranded loop section of dNA formed by the association of a section of ssRNA with the other strand of the dna in this region whereby one dna strand is displaced as the loop. This patent from IBM claims a method of forming an electronic device such as a resonant tunneling diode using such R-loops to bind with nanoparticles. Claim 1 reads:

1. A method of fabricating an electronic device using biomolecules comprising: forming first and second electrodes on a substrate; extending bridging DNA between said first and second electrodes; providing at least one RNA complementary to a region of said bridging DNA wherein said at least one RNA and said bridging DNA bond to form at least one R-loop; and bonding at least one nanoparticle to said DNA within said at least one R-loop.

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Wednesday, May 09, 2007

US Patent 7214427 - Quantum dot tag subject to microfluidic control

Electrophoretic pumping is a method using electric fields to move minute quantities of fluid applicable to biological and chemical analysis. This patent from Aviva Biosciences teaches the formation of beads to facilitate such pumping and which can also be used as quantum dot tags for tracking particular biofluids. Claim 22 reads:

22. A bead, which bead comprises: a) a magnetizable substance; and b) an electrically conductive substance, and a quantum dot.

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US Patent 7214303 - Branched nanostructure for atomic force microscopy

The atomic force microscope (AFM) and related proximity probes have been used for nanoscale analysis since the 1980's. More recently nanotubes have been formed on the tips of AFMs to provide higher resolution and allow for inspection of high aspect ratio cavities in substrates. This patent from Boston College teaches using a branched (Y-junction) nanotube as a nanocantilever structure for an AFM. Claim 1 reads:

1. A cantilever probe comprising: a first electrode and a second electrode engaged to a substrate; a branched cantilever comprising a nanostruture; a first arm of the cantilever engaging the first electrode and a second arm of the cantilever engaging the second electrode; and an electrical circuit coupled to the cantilever wherein the electrical circuit measures a change in piezoresistance of the cantilever resulting from an atomic force applied to the cantilever.

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Tuesday, May 08, 2007

US Patent 7213923 - Fluorescent nanoparticles in transparent substrate

Fluorescence is generally defined as the emission of electromagnetic radiation, generally visible light, stimulated in a substance by the absorption of incident radiation and persisting only as long as the stimulating radiation is continued. The use of quantum dots to achieve fluorescence has been known for decades and may have existed since medieval times when artisans made stained glass windows. Nevertheless this patent presents a broad claim to transparent substrates with fluorescent nanoparticles (which may include atoms, molecules, or any other particles less than 500 nm in diameter). Claims 1, 37, and 38 reads:

1. An apparatus comprising light emitting material integrated into a substantially transparent substrate, wherein: the light emitting material is configured to emit visible light in response to absorption of excitation light; the wavelength of the visible light varies according to the wavelength of the excitation light; the light emitting material comprises a plurality of light emitting particles; and each of the plurality of light emitting particles has a diameter less than about 500 nanometers.

37. The apparatus of claim 1, wherein each of the plurality of light emitting particles is an individual molecule.

38. The apparatus of claim 1, wherein each of the plurality of light emitting particles is an individual atom.

While these claims would seem to place the holder of this patent (a company called Superimaging) as the owner of all fluorescent materials (especially in light of claims 37 and 38 since everything is fundamentally made of atoms or molecules and the physics of fluorescence happens on the molecular or atomic level) there is plenty of prior art missed (or not understood) by the Examiner to invalidate this patent. See for example US 7,094,361


US Patent 7213637 - Heat pipe with inner carbon nanotube coating

This patent from Hon Hai Precision proposes using carbon nanotubes in the interior of heat pipes which use capillary force to effect efficient thermal transfer. While carbon fibers were used in the prior art the size of the fibers disrupted the capillary flow. Claim 1 reads:

1. A heat pipe comprising: a vacuumated pipe; a wick having a capillary structure engaged with an inside wall of the pipe; and an operating fluid sealed in the pipe and soaking the wick; wherein the wick comprises a carbon nanotube layer, and the operating fluid comprises a liquid and a plurality of nanometer-scale particles suspended in the liquid.

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Monday, May 07, 2007

US Patent 7211853 - Nanotube FET

There has been some speculation as to whether Moore's law (referring to the exponential increase in transistor density over time) will eventually require nanotube FETs (FET= field effect transistor). Several companies already have patents on this technology and one might ask the question of whether there is a fundamental nanotube FET out there. This patent is assigned to a European University ( which makes a claim with priority going back to July 26, 2001. Claim 1 reads:

1. An electronic device comprising a tubular shaped carbon molecule supported by a substrate, which molecule is provided with source and drain electrodes directly contacting said carbon molecule, as well as a gate electrode, wherein the gate electrode is a metallic electrode.

However, the Examiner may have overlooked some relevant prior art such as

US 6566704 (

which has U.S. filing priority going back to June 27, 2001 and is owned by Samsung. This patent provides a basic claim to a vertical carbon nanotube transistor. Claim 1 reads:

1. A vertical nano-sized transistor using carbon nanotubes comprising: an insulating layer having holes, the holes having nano-sized diameters; carbon nanotubes vertically aligned in the holes; gates formed over the insulating layer in the vicinity of the carbon nanotubes; a nonconductor film deposited on the gates to fill the holes; drains formed over the nonconductor film and the carbon nanotubes; and sources formed under the insulating layer and the carbon nanotubes.

or perhaps this article from IBM published in 1998 may shed some light on the validity of this patent (see Fig. 1)

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Friday, May 04, 2007

US Patent 7212026 - Quantum cellular automata with nanodomains

Conventional logic systems are based on the flow and storage of electron charge. Quantum Cellular Automata is an alternative logic system capable of producing logical operations which conventionally operate by determining the discrete state of particles arranged in cells via an electrostatic or magnetic interaction with particles in neighboring cells. This patent from Intel uses "nano-domains" in which the logic state is represented by electron spin or orbital state of the nano-domains.

1. A logic device comprising: a collection of unit cells with significant quantum exchange interaction between the constituents of the cells, the unit cells being composed of nano-domains of lattice cells within a single crystal comprising the thin film, the logical state of the said device being represented by the spin state or orbital state of said unit cells.

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US Patent 7211503 - Microscale to nanoscale electronics conversion using random interconnections

A variety of companies including Hewlett-Packard and Nanosys are working on using nanowires to form electronic memories, circuits and other devices. However, the processing used in forming the nanowires on a substrate (such as nanoimprint lithography, self-assembly, etc.) is very different from the processing (such as optical lithography) conventionally used in forming microscale wires and the two scales of wiring are thus usually formed in separate processing steps. Interconnection between microscale wires and nanowires thus requires new methodologies. This patent from HP proposes a microwire to nanowire addressing scheme based on randomly distributing nanowires across microwires and only using the portion of the nanowires achieving proper connections rather than trying to form the nanowires in a predetermined manner. Claim 1 reads:

1. A random microscale-to-nanoscale interface comprising: a number N of approximately parallel nanowires; a number M, where M>log.sub.2N, of approximately parallel microscale or sub-microscale address signal lines that are not parallel with respect to the N nanowires and that form a grid-like set of intersections with the N nanowires; and a random or pseudorandom distribution of interconnections within the grid-like set of intersections.

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Wednesday, May 02, 2007

US Patent 7211464 - Uniform diameter nanowires

Electronic parameters of nanowires such as bandgap are dependent on the diameter of the nanowire. This patent originating from Harvard researches presents a very broad claim towards a method of growing nanowires of uniform diameter (give or take 20%) to achieve more consistent electronic device functionality. Claim 1 reads:

1. A method, comprising: growing a population of semiconductor nanowires, each having at least one portion having a smallest width less than 500 nanometers, catalytically from catalyst colloid particles having a variation in diameter of less than about 20% and being selected such that the population of semiconductor nanowires produced according to the method has a variation in diameter of less than 20%.

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US Patent 7211320 - CNT sieve

This patent proposes using carbon nanotubes for desalination/sterilization purposes by intentionally causing defects in the carbon rings to more easily separate contaminates from fluids. Claim 1 reads:

1. A material for reducing contaminants in a fluid, said material comprising: carbon nanotubes, and a porous support medium for said carbon nanotubes, said porous support medium being permeable to the flow of said fluid, wherein a plurality of said carbon nanotubes comprise: a lattice distortion, at least one functional group, and are fused or bonded to said porous support medium, to another carbon nanotube, or to a combination thereof.

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Tuesday, May 01, 2007

US Patent 7211143 - Nanotube fabrication using nanowire template

Besides carbon other inorganic nanotubes are gaining some interest, however manufacturing techniques are less well developed for non-carbon nanotubes. Some success has been achieved using porous substrates such as anodic aluminum oxide (AAO) to grow nanowires but removal of the AAO template can often cause unwanted agglomeration of the nanotubes. This patent from the University of California teaches using nanowires as a removable template for better results. Claim 1 reads:

1. A method for fabricating a nanotube, comprising: forming a nanowire; depositing at least one sheath of material over said nanowire; and removing said nanowire; wherein said remaining sheath material comprises said nanotube; and wherein said nanotube is formed as an epitaxial casting.

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US Patent 7210337 - MEMS leak detector

One of the largest markets for MEMS is motion sensors which utilize the resonant response of a proof mass to detect movement. However, the pressure of the environment in which the MEMS device is encapsulated can alter the resonant response. This patent from Honeywell seeks to detect leaks in a MEMS package to detect pressure changes having unwanted effects on the sensors operation.

1. A method for detecting a leak in a MEMS sensor package, wherein the MEMS sensor package includes a sensor cavity that encloses a MEMS sensor, wherein the MEMS sensor includes a mechanical oscillating element with a Quality (Q) value, the method comprising: measuring a first Q value of the MEMS sensor at a first time; applying a pressure differential between the sensor cavity and the exterior of the MEMS sensor package; and measuring a second Q value of the MEMS sensor at a second time, wherein the second time is later than the first time.

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