Monday, July 31, 2006

US Patent 7081664 - Doped Silicon Nanocrystal Powder

While silicon is extensively utilized to form electronic devices it is typically not a favorable material for optical applications such as solid state LEDs which more commonly employ compound semiconductors such as gallium arsenide. This patent is based on the finding that silicon nanocrystals that includes rare earth elements such as erbium, thulium, or europium have enhanced photoemission properties. Claim 1 reads:

1. A doped semiconductor powder comprising nanocrystals of a group IV semiconductor and a rare earth element, the rare earth element being dispersed on the surface of the group IV semiconductor nanocrystals.

Sunday, July 30, 2006

US Patent7081322 - Printing Plates Formed By Ink Jettable Nanopaste

Numerous printing technologies are currently being employed as a cheap alternative to support nanofabrication. Inkjet technology is a particularly favorable avenue to explore since it may be used to deposit large quantities of nanoparticles selectively without the need for the traditional (and expensive) equipment used in traditional semiconductor fabrication. This patent uses inkjeting of metallic nanoparticles to form a printing plate. Claim 1 reads:

1. A method for forming an image on a substrate comprising: providing a hydrophilic substrate; imagewise ink-jet applying onto a surface of the hydrophilic substrate a nanopaste comprising metal nanoparticles and a carrier; and treating the nanopaste to form an ink-receptive image area.

US Patent 7081293 - Nanowire with Aspect Ratio>100,000

Nanowires are usually defined as cylindrical structures having a nanometer diameter and a high aspect ratio. However, in order to construct useful devices such as electrical conductors it is useful to have very high aspect ratio nanowires. This patent from General Motors describes a new fabrication method enabling aspect ratios of greater than 100,000 to be created. Thus nanowires with diameters measured in the tens of nanometers may have lengths in the millimeter range. Claim 1 reads:

1. A metallic nanowire composed of at least one of bismuth, indium, tin, lead, zinc, antimony, alloys containing bismuth, alloys containing indium, alloys containing tin, alloys containing lead, alloys containing zinc and alloys containing antimony, the metallic material present in at least one single elongated crystal having an aspect ratio of greater than or equal to 100,000.

Tuesday, July 25, 2006

US Patent 7080596 - Silicon Carbide Nanoimprint Stamp

As mentioned in earlier posts, printing technologies are currently being used to replace optical lithography in nanofabrication. Some of these printing based techniques employ nanoimprint lithography stamps and are used for stamping and embossing functions that mirror many of the oldest printing technologies. However, the problem with using manoimprint stamps is that they can be fragile and are not suitable for extended and repeated use. This patent from HP proposes a more durable structure for nanoimprint stamps. Claim 1 reads:

1. A micro-casted silicon carbide nano-imprinting stamp, comprising: a handling substrate; a glue layer connected with the handling substrate, wherein the glue layer comprises a material selected from the group consisting of tungsten, titanium, titanium nitride, cobalt, platinum, gold, a gold-tin alloy, silver, and a silicide; a foundation layer connected with the glue layer and including a base surface; and a plurality of nano-sized features connected with the foundation layer and extending outward of the base surface, the nano-sized features including an outer surface defining an imprint profile, the foundation layer and the nano-sized features are a micro-casted unitary whole and are made entirely from a material comprising silicon carbide, and wherein a hardness of the silicon carbide is operative to maintain the imprint profile of the nano-sized features over repeated engagements of the nano-imprinting stamp with a media to be imprinted.

Monday, July 24, 2006

US Patent 7078683 - Nanowire Sample Holder For Mass Spectrometer

Last week I mentioned a patent that included nanotubes in the housing of a mass spectrometer. This patent also uses nanostructured material, this time nanowires, to improve mass spectrometers by providing an increased surface-to-volume area for the sample. Claim 9 is representative:

9. An ion source for use in ionizing a sample, comprising: (a) a laser; and (b) a nanowire surface for holding the sample.

This patent also explicitly excludes carbon nanotubes from the definition of nanowire. I have also seen patents which explicitly include nanotubes from the definition of nanowires. For patents that do not explicitly exclude or include nanotubes as a type of nanowire this divergence of nomenclature may eventually create some legal confusion.

Sunday, July 23, 2006

US Patent 7078276 - Fabrication Using Nanoparticle Ink Annealing

Use of nanoparticle based ink is an attractive low-cost alternative to optical lithographic processes since it only requires printing methodologies such as inkjet or imprint lithography which present fewer environmental constraints. This patent proposes using annealing of a deposited nanoparticle ink layer in a metal oxide matrix to form doped surface layers for thin filf transistors or other devices. Claim 1 reads:

1. A method of fabricating a device layer comprising: a. depositing a layer of nanoparticle ink onto a substrate structure; and b. annealing the nanoparticle ink, wherein nanoparticles from the nanoparticle ink fuse together and wherein the nanoparticles comprise nanoparticles formed by treating a metal monoxide to form a composite material comprising a metal oxide matrix and the nanoparticles embedded therein and isolating the nanoparticles from the composite material.

Thursday, July 20, 2006

US Patent 7077939 - Carbon Nanotube Conduit For Nanofluidic Transport

Microfluidics is an active technology area dealing with the processing of fluids on the microscale. This technology is gradually being extended to the nanoscale for the control of the processing of individual or small groups of molecules. This patent uses a carbon nanotube embedded in a membrane as a molecular sieve/filter useful in sensing and other applications. Claims 1 and 6 are representative.

1. An apparatus comprising: a membrane; a nanotube embedded within the membrane and providing a conduit through the membrane, the ends of the nanotube being flush with respective surfaces of the membrane; and wherein the nanotube is a carbon nanotube.

6. A method of forming a membrane having a small hole disposed therein comprising: surrounding at least a portion of a nanotube with a liquid or gaseous material; allowing the liquid or gaseous material to solidify around the nanotube; and removing by chemical oxidation the at least a portion of the nanotube from the solidified material, leaving the membrane having the small hole disposed therein.

Note to patent attorneys: in this case the Examiner took a very broad interpretation of nanotube and applied art showing a membrane with a nanosized tubular aperture which was interpreted by the Examiner as a "nanotube". While I'm not sure this interpretation would have held at the Board of Appeals and it seems contrary to the understanding of one of ordinary skill in the nanotechnology art, a tube is broadly defined by Merriam-Webster's as "any of various usually cylindrical structures or devices." The prosecuting attorney got around the rejection by specifying "carbon" nanotube in claim 1 which may come back to haunt them if other non-nanotube structures such as charcogenide nanotubes are used as alternatives to practicing this invention.

Wednesday, July 19, 2006

US Patent 7077329 - Quantum Dots for Document Security

Quantum dots (i.e. nanosized crystals) are frequently being applied as biological tags to track molecules in analytical devices via a fluorescent effect. In addition, quantum dots may be used as security tags similar to bar codes to mark print media (such as by a printing device) but with the advantage of being undetectable by human or other traditional inspection. This would be highly useful for anti-counterfeiting, document tracking, and other security issues. This patent advances this use of quantum dots via processing algorithms used to decode the data. Claim 1 reads:

1. A method of decoding information encoded by the positions and intensities of spectral lines in the emission spectrum of quantum dots in a carrier medium, wherein a set of codes in a code book is characterized by different combinations of said positions and intensities, comprising: exciting the quantum dots in said carrier medium to initiate fluorescence; sensing the resulting emission spectrum of the quantum dots; performing a deconvolution operation to separate the spectral lines in said emission spectrum; processing the resulting data to find the positions and intensities of the spectral lines in said emission spectrum; and extracting the decoded information by reference to said code book; and wherein the de-convolution operation is represented by the equation .SIGMA..sub.i k(.lamda.i).delta.(.lamda.-.lamda.i)=IFT {FT[f(.lamda.)]/FT[p(.lamda.)]}, where .delta.(.lamda.) represent an impulse function, k(.lamda.i) is the intensity of a .delta.(.lamda.) at .lamda.i, p(.lamda.) denotes the profile function of the spectrum of quantum dots.

Tuesday, July 18, 2006

US Patent 7076871 - Ohmic Contact With Nanotube Using Evaporaton

In order for individual nanotubes to be used to construct electronic devices bonding between nanotubes and electrodes must be accomplished. This has usually been accomplished by fusion bonding, in which high temperatures are used to facilitate the connection. Unfortunately the high temperatures can also damage the nanotubes. This patent proposes an alternative that uses a scanning probe tip for field evaporation of titanium particles to accomplish the bonding at lower temperatures. Claim 1 reads:

1. A method of manufacturing a carbon nanotube device including an inner electrode, the method having a connecting step that connects a carbon nanotube to the inner electrode, wherein the connecting step comprises: attaching a conductor in a particulate form to an end or periphery thereof of a needle-shaped or rod-shaped carrying electrode; arranging the carbon nanotube in contact with or close to a predetermined connection part of the inner electrode; approaching the end of the carrying electrode on which the particulate form conductor is carried to the connection part; and transferring the particulate form conductor carried on the carrying electrode to the connection part or periphery thereof to connect the carbon nanotube to the inner electrode.

Monday, July 17, 2006

US Patent 7076138 - Quantum Dots Embedded in Bandgap Medium for Nanophotonics

All optical photonics is being experimented with at various levels to get around the attenuation effects that occur in electronics. Several opportunities (and dangers) exist if this technology is successful such as massively parallel processing computation (which may mean an end to many current cryptography methodologies used in data encryption for secure banking and internet transactions). The problem with photonics in general is that the optical amplifiers that have been built are difficult to scale down. This patent proposes one route to nanophotonics using an arrangement of quantum dots in a frequency bandgap medium. Claim 1 reads:

1. A nonlinear optical and electro-optical material for optical signal processing, spectral and spatial filtering, light amplification or generation comprising a frequency bandgap medium exhibiting at least one photonic bandgap forbidden for electromagnetic modes of the light propagating in at least one direction, a set of quantum systems including at least one atom, molecule or quantum dot having at least two degenerate or non-degenerate discrete energy levels with at least one working transition between the energy levels interacting with the light, wherein said set of quantum systems is embedded into said frequency bandgap medium, and frequency of said at least one working transitions between the energy levels of the quantum systems lies inside the said photonic gap of the frequency bandgap medium developing a photonic passband inside the photonic bandgap and ensuring efficient suppression of spontaneous decay of the upper energy state of the working transition.

Sunday, July 16, 2006

US Patent 7075067 - Composite Nanotube Housing For Mass Spectrometer

Mass spectrometry is used to analyze the chemical constituents of substances by examining the charge to mass ratio of the constituents. However, the housings of mass spectrometers can present problems such as reactions with the material that is being analyzed that reduce the effectiveness of the measurement. This patent proposes to use composite nanotube material in the housing which are less reactive with the analytes. Claim 1, 8 and 22 are representative.

1. An ionization chamber for a mass spectrometry system comprising: a housing defining an ionization region, the housing comprising a carbon nanotube material wherein the carbon nanotube material comprises a carbon nanotube composite material.

8. An ion source for a mass spectrometry system, comprising: an ionization chamber comprising an inert carbon nanotube composite material.

22. An ionization chamber for a mass spectrometry system comprising: a housing defining an ionization region, the housing comprising a non-emitting carbon nanotube composite material.

Although the Examiner applied prior art employing electron emissive nanotubes to reject some of the claims the attorney argued that the limitations in the claims were supported by the specifications limitation to non-electron emitting (i.e. inert) nanotubes or nanotube composites solely for the purpose of forming the ionization chamber housing.

Thursday, July 13, 2006

US Patent 7074463 - Nanoparticles for Brightness Enhancing Films

Electronic displays such as LCDs employ special films to enhance the brightness. However, these films are often subject to scratches. This patent teaches using nanoparticles to produce films with more durability. Claims 1, 18, and 37 are representative.

1. A durable optical film comprising: a polymerized optical film structure having a microstructured surface and a plurality of surface modified colloidal nanoparticles of silica, zirconia, or mixtures thereof.

18. A brightness enhancing film comprising: a brightness enhancing polymerized structure having a plurality of surface modified colloidal nanoparticles.

37. A retro-reflective film comprising: a retro-reflective polymerized structure having a plurality of surface modified colloidal nanoparticles.

Wednesday, July 12, 2006

US Patent 7074260 - Nanotube Filter For Air Conditioner

Carbon materials have been used in the past in filters of air conditioners for adsorption of contaminants. This patent from Samsung teaches that nanotubes have increased ability at removing VOCs (volatile organic compounds) in an air conditioner. Claim 1 reads:

1. A filter for an air conditioner, comprising: a carbon nanotube, wherein nano-sized metal particles of at least one type of metal are deposited into the carbon nanotube.

Tuesday, July 11, 2006

US Patent 7073937- Nanotube Heater for Scanning Probe Memory

Most are familiar with magnetic or optical discs for high density data storage but less may be familiar with phase change high density data storage devices. This is an approach currently being experimented with by IBM's "millipede" project and includes the formation of pits in a thermally sensitive medium by an array of ultrasharp heated tips of scanning probe microscopes so as to store data. In order to further increase the resolution of such devices this patent from Daiken Chemical (Japan) proposes using heated nanotubes for the writing tips. Claim 1 reads:

1. A heat emitting probe comprising: a conductive carbon nanotube probe needle with a base end portion thereof fastened to a holder and a tip end portion thereof protruding from said holder, a heat emitting body provided on a circumferential surface of said conductive carbon nanotube probe needle, a conductive carbon nanotube lead wire whose one end is fastened to said heat emitting body, and a means for causing an electric current to pass through said heat emitting body by applying a voltage between said conductive carbon nanotube lead wire and said conductive carbon nanotube probe needle so that said heat emitting body is heated by said electric current.

Monday, July 10, 2006

US Patent 7073157 - Signal Restoration for Molecular Electronics

Molecular electronics concerns individual or small groups of molecules acting as resistors, transistors, or other electronics elements. Within the past few years Hewlett Packard has led the way in developing a platform for developing molecular electronics by exploiting crossbar array architectures that uses crossed p and n doped nanowires separated by molecular films to form crosspoints as connection elements for molecular electronic junctions. While HP is the predominant force behind the development of crossbar molecular electronics, this patent, based on a cooperative venture between Caltech and Harvard, adds to the collective knowledge of crossbar molecular electronics by providing teachings relevant to signal restoration. Claim 1 reads:

1. An architecture for nanoscale electronics comprising: arrays of crossed nanoscale wires, each array comprising a plurality of crosspoints between nanoscale wires, the crosspoints being selectively programmable, wherein nanoscale wires of one array are shared by other arrays, thus providing signal propagation between the one array and the other arrays; nanoscale signal restoration elements, allowing an output of a first array to be used as an input to a second array, wherein signal restoration occurs without routing of the signal to non-nanoscale wires; and nanoscale driving devices of crossed nanoscale wires for selectively programming at least some of the crosspoints.

Sunday, July 09, 2006

US Patent 7071406- Single Walled Nanotube Array

Rice University (aka Smalley et al.) continues in its efforts to corner the market on single walled nanotubes with this patent. Claim 1 reads:

1. A macroscopic molecular array comprising at least about 1,000,000 single-wall carbon nanotubes, wherein (a) all of the single-wall carbon nanotubes in the macroscopic molecular array are in generally parallel orientation, and (b) all of the single-wall carbon nanotubes in the macroscopic molecular array have a substantially similar length, wherein the similar length is in the range of from about 5 to about 500 nanometers.

US Patent 7071258 - Nanoscale Graphite

Graphite is one form of crystalline carbon found in everyday objects such as pencils. In this form the carbon atoms are arranged as a plurality of adjacent lattice planes that are relatively movable with respect to one another and which allow for electrical conduction. Individual atomic layers of graphite are referred to as graphene and a graphene sheet rolled into a tube of nanometer dimensions is equivalent to a carbon nanotube. While carbon nanotubes are seen as very useful for their mechanical and electrical properties it is difficult to manufacture nanotubes in bulk at a low cost. The inventors of this patent propose using nanoscale graphite instead to achieve some of the advantages of nanotubes but at less cost. Claim 1 reads:

1. A nano-scaled graphene plate material comprising at least a nanometer-scaled plate with said plate comprising a sheet of graphite plane or a multiplicity of sheets of graphite plane; said graphite plane comprising a two-dimensional hexagonal lattice of carbon atoms and said plate having a length and a width parallel to said graphite plane and a thickness orthogonal to said graphite plane characterized in that the length, width, and thickness values are all smaller than 10 nanometers.

Thursday, July 06, 2006

US Patent 7070923 - Nanotube Paper Immunity Shield

Cell transplantation is useful for gene therapy and other medical treatments however there is difficulty is providing cell transplantation without resistance from the hosts immune system. This patent proposes using paperlike material formed of nanotubes which is sufficiently biocompatible to shield transplanted cells from an immune system but also sufficiently porous to allow some communicaton with the cell. Interestingly this patent is from NASA who apparently have interests beyond avionics and space science. Claim 1 reads:

1. A system for enclosing a biological tissues or group of cells for positioning within an ambient medium, the system comprising: a cage or envelope of a cage material that includes primarily carbon nanotube Bucky paper ("CNTBP"), the cage having at least one of a cage thickness in a range 1-100 microns and a cage area density in a range of 420 1500 micrograms/square cm, where the cage encloses at least one of a biological tissue or a group of cells (referred to herein as a "biological insert") and an interior of the cage is substantially isolated from an ambient medium surrounding the cage, except for transport at least one species of molecule between the cage interior and the ambient medium.

Wednesday, July 05, 2006

US Patent 7070754 - Conductive SWNT Rope

Single walled carbon nanotubes (SWNTs) are either conductive or semiconductive depending on the direction of "wrapping" of the nanotubes. The established way to distinguish between different single walled nanotubes is in terms of the vector (n,m) identying the direction of such "wrapping" where n and m are integers. If n=m, or n-m is divisible by 3, than the SWNTs are conductive and otherwise they are semiconductive. Unfortunately, many techniques for fabricating SWNTs produces only a low relative concentration of the conductive nanotubes relative to the semiconductive nanotubes, which is undesirable when attempting to produce conductors such as for electrical wiring. Smalley's group at Rice University discovered/invented manufacturing techniques to overcome this problem ten years ago and, after pending for ten years, a patent for the product is just now issued.

Claim 8 is representative.

8. A single-wall carbon nanotube rope comprising at least 50 single-wall carbon nanotubes of which greater than 10% of the single-wall carbon nanotubes are (n, n) single-wall carbon nanotubes.

Tuesday, July 04, 2006

US Patent 7068898 - Nanocomposite With Type II Band Offset Nanostructures

Solar cells is one area gathering a lot of interest for nanotechnology applications. It is seen by some that nanocomposites may provide a significant increase in efficiency as well as enabling the creation of flexible solar panels. This particular patent uses core/shell nanoparticles with a type II band offset between the core and shell semiconductor material (meaning that there is an overlap between one, but not both, of the valance and conduction bands of the core and shell material). Claim 1 reads:

1. A composite material, comprising: a matrix; and one or more nanostructures, the one or more nanostructures each comprising a core and at least one shell, the core comprising a first semiconducting material having a conduction band and a valence band, the shell comprising a second semiconducting material having a conduction band and a valence band, and the first and second materials having a type II band offset.

US Patent 7068874 - Microfluidic Sorting Using Optical Switch

Microfluidics involves the manipulation of very small quantities of fluid and is useful for biological fluid processing and analysis. Often mixing or sorting of various biological fluids are performed for medical diagnostics using microfluidics and micromechanical switches or flow control using electrophoretic forces are involved in the sorting. However, more precise switching mechanisms are desirable. This patent provides for an optical switching mechanism to control the sorting of microfluidic particles. Claim 1 reads:

1. A microfluidic sorting device comprising: a substrate having a main microfluidic channel that branches into a plurality of microfluidic branch channels, the main microfluidic channel and the plurality of microfluidic branch channels adapted to contain a moving fluid having particles disposed therein; and a light source that produces at least one light beam directed at the main microfluidic channel, the light beam selectively switching the particles into the plurality of microfluidic branch channels without optically trapping the particles.

Sunday, July 02, 2006

US Patent 7068225 - Nanoantenna (or is it?)

Perhaps the invention of the previous post may make use of this invention. Although I am a little skeptical of the presented claims after reading the specification. Claim 1 reads:

1. A nano-antenna apparatus, said apparatus comprising: a first conducting surface; a second conducting surface; a gap region between said first conducting surface and said second conducting surface; and at least one discharge switch.

With the exception of the word "nano-antenna" didn't Nikola Tesla (and later Marconi) patent this over a hundred years ago?
Since the specification of this patent gives exemplary sizes of the antenna in the millimeter range and does not teach any specialized manufacturing technique to reduce the size or utility to the nanoscale this patent seems highly questionable.

US Patent 7068170 - RFID Paint

RFID tags are basically tiny microchips used for identification similar to bar codes but using radio wave communication. The radio wave energy used to send and receive information from the tags are also used to power the tag and the tags include memory to assist in the identification. Usually the RFID tags are formed from microchips but there has been interest in the use of flexible substrates for the RFID tags to expand the areas of use. This patent from Boeing goes a step further and teaches embedding ultrasmall RFID tags (<0.25 square millimeters) in a liquid to be coated on a surface. In some empodiments, MEMS based temperature or pressure sensors are also included in the paint to achieve smart paint that may communicate diagnostic information. Independent claims 1, 11, and 21 read:

1. A method of identifying a product, comprising: introducing at least one radio frequency identification tag into a liquid being able to retain the tag when the liquid is applied to a surface; further comprising applying the liquid to coat the surface.

11. A mixture, comprising: a liquid; and a plurality of radio frequency identification tags in the liquid wherein the liquid being able to retain the tags when the liquid is applied to a surface.

21. An article of manufacture, comprising: a surface; a coating on the surface; and at least one radio frequency identification tag in the coating, the coating being able to retain the tag when the coating is a liquid and when the liquid is applied to the surface.

Saturday, July 01, 2006

US Patent 7067867 - Core/Shell Nanowire Transistor

Nanosys is a company that is putting forth a strong effort to monopolize nanowire FETs and their application in large area electronics suitable for flexible displays, RFID, and other emerging applicatons. Nanowires can be p-doped or n-doped and placed between source and drain electrodes to created nanotube FETs. This patent teaches adding a coating to the nanowires to prevent electron/hole recombination which reduces mobility. Claim 57 reads:

57. A semiconductor device comprising: a substrate; a plurality of nanowires deposited on the substrate, wherein each of said plurality of nanowires comprises a core made of a first material and a first shell layer made of a second material disposed about said core, wherein said first material is compositionally different from said second material; and at least a first source contact and a first drain contact formed in or on the substrate providing electrical connectivity to the plurality of nanowires, wherein the plurality of nanowires form a channel between said at least first source and drain contacts.

US Patent 7067328 - Nanofabrication Using Transfer Printing

In addition to optical lithography, as in the previous posting, alternative nanofabrication techniques can be found using techniques common to the printing industry. Conductive or semiconductive nanoparticles can be placed in a carrier fluid and used as "inks" that are selectively placed on a variety of substrates. It is not unlikely that a few years down the line desktop circuit fabricators will be as common as desktop printers. Those companies investing in nanoelectronics that have experience in printing (HP is one example) may have a huge advantage if electronics fabrication continues to evolve toward printing based fabrication.

This patent focuses on transfer based printing to transfer nanoparticles from a transfer substrate roll to a receiving substrate. Claim 1 reads:

1. A method of depositing nanomaterials onto a substrate, comprising: providing a plurality of nanostructures disposed upon a transfer substrate wherein the transfer substrate is disposed on a roll; providing an adherent material deposited on one or more selected regions of a receiving substrate; mating the transfer substrate with the receiving substrate whereupon the nanostructures contact the nanostructures on the transfer substrate with the one or more selected regions of the receiving substrate; and separating the transfer substrate from the receiving substrate to leave a population of nanostructures adhered to the one or more selected regions of the receiving substrate.

US Patent 7067237 - Selective Nanowire Growth

There is much interest in methods of forming arrays of nanostructures using traditional lithography approaches. The reason for this is that so much investment in terms of money and research has already been made in optical lithography that the industry is reluctant to switch to alternative methods. In addition, optical lithography is suited for mass production. This patent uses optical lithography for catalyst patterning, metal coating of the patterned catalyst to form a metal pattern, and nanowire growth on the metal pattern to achieve selectively patterned nanowire structures. Claim 1 reads:

1. A method for forming a pattern of a one-dimensional nanostructure, comprising the steps of: (i) coating a photocatalytic compound onto a substrate to form a photocatalytic film, and selectively exposing the photocatalytic film to light to form latent image centers for crystal growth; (ii) growing metal crystals by plating the latent pattern to form a metal pattern; and (iii) selectively growing a one-dimensional nanostructure on the metal pattern acting as a catalyst.