US20070128101A1 - Method of forming a heterojunction of a carbon nanotube and a different material, method of working a filament of a nanotube - Google Patents

Method of forming a heterojunction of a carbon nanotube and a different material, method of working a filament of a nanotube Download PDF

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US20070128101A1
US20070128101A1 US11/671,883 US67188307A US2007128101A1 US 20070128101 A1 US20070128101 A1 US 20070128101A1 US 67188307 A US67188307 A US 67188307A US 2007128101 A1 US2007128101 A1 US 2007128101A1
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filament
carbon nanotube
heterojunction
nanotube
swcnt
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Yuegang Zhang
Sumio Iijima
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NEC Corp
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NEC Corp
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Priority claimed from JP14704199A external-priority patent/JP3518422B2/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/20—Carbon compounds, e.g. carbon nanotubes or fullerenes
    • H10K85/221—Carbon nanotubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
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    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/158—Carbon nanotubes
    • C01B32/168—After-treatment
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/90—Carbides
    • C01B32/914—Carbides of single elements
    • C01B32/956—Silicon carbide
    • C01B32/963—Preparation from compounds containing silicon
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    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
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    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K10/00—Organic devices specially adapted for rectifying, amplifying, oscillating or switching; Organic capacitors or resistors having a potential-jump barrier or a surface barrier
    • H10K10/20—Organic diodes
    • H10K10/29—Diodes comprising organic-inorganic heterojunctions
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    • H10K10/00—Organic devices specially adapted for rectifying, amplifying, oscillating or switching; Organic capacitors or resistors having a potential-jump barrier or a surface barrier
    • H10K10/701—Organic molecular electronic devices
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    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H10K71/20—Changing the shape of the active layer in the devices, e.g. patterning
    • H10K71/211—Changing the shape of the active layer in the devices, e.g. patterning by selective transformation of an existing layer
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S977/00—Nanotechnology
    • Y10S977/70—Nanostructure
    • Y10S977/701—Integrated with dissimilar structures on a common substrate
    • Y10S977/72—On an electrically conducting, semi-conducting, or semi-insulating substrate
    • Y10S977/721—On a silicon substrate
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S977/00—Nanotechnology
    • Y10S977/70—Nanostructure
    • Y10S977/734—Fullerenes, i.e. graphene-based structures, such as nanohorns, nanococoons, nanoscrolls or fullerene-like structures, e.g. WS2 or MoS2 chalcogenide nanotubes, planar C3N4, etc.
    • Y10S977/742—Carbon nanotubes, CNTs
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S977/00—Nanotechnology
    • Y10S977/70—Nanostructure
    • Y10S977/734—Fullerenes, i.e. graphene-based structures, such as nanohorns, nanococoons, nanoscrolls or fullerene-like structures, e.g. WS2 or MoS2 chalcogenide nanotubes, planar C3N4, etc.
    • Y10S977/742—Carbon nanotubes, CNTs
    • Y10S977/744—Carbon nanotubes, CNTs having atoms interior to the carbon cage
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S977/00—Nanotechnology
    • Y10S977/84—Manufacture, treatment, or detection of nanostructure
    • Y10S977/842—Manufacture, treatment, or detection of nanostructure for carbon nanotubes or fullerenes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S977/00—Nanotechnology
    • Y10S977/84—Manufacture, treatment, or detection of nanostructure
    • Y10S977/842—Manufacture, treatment, or detection of nanostructure for carbon nanotubes or fullerenes
    • Y10S977/844—Growth by vaporization or dissociation of carbon source using a high-energy heat source, e.g. electric arc, laser, plasma, e-beam
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/21—Circular sheet or circular blank
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2902—Channel shape

Definitions

  • This invention relates to a method of forming a heterojunction of a carbon nanotube and a different material and, in particular, to a method of forming a heterojunction of a carbon nanotube and carbide.
  • This invention relates also to a filament, a method of inducing an electric current therein, and a method of working the same and, in particular, to a filament having a nanostructure and adapted for use in a micromachine and an electron source, a method of inducing an electric current therein, and a method of working the same.
  • a so-called heterojunction formed by heterogeneous or different materials is an important structure in order to utilize material-specific characteristics in an electronic device.
  • a carbon nanotube comprises a graphite sheet composed of six-member carbon rings and has a cylindrical structure formed by rolling the graphite sheet in a manner such that the six-member carbon rings are aligned in a helical fashion.
  • the carbon nanotube together with a spherical fullerene represented by C 60 , is expected as a useful material for an electronic device because of its specific electric characteristics. Particularly, attention is directed to a bond of the carbon nanotube and carbide.
  • carbide itself has very interesting electric characteristics.
  • SiC has semiconducting features.
  • TiC has metallic features.
  • Fe 3 C acts as a ferromagnetic material.
  • NbC attracts the attention as a superconducting material.
  • BC x serves as an insulator.
  • carbide has a wide variety of electric characteristics.
  • a single-wall carbon nanotube has specific electric characteristics. That is, the single-wall carbon nanotube acts as a semiconductor or a metal in dependence upon a diameter and a helical condition (an angle formed between an axial direction of the nanotube and an aligning direction of carbon atoms) (M. S. Dresselhaus et al “Science of Fullerenes and Carbon Nanotubes” (Academic Press, New York, 1996)). It is expected that various functional devices can be achieved by a combination of carbide and the carbon nanotube.
  • SWCNT single-wall carbon nanotube
  • the SWCNT comprises a hexagonal network graphite plane rolled into a cylindrical shape.
  • the SWCNT has an electron structure widely varied depending upon a tube diameter and a chiral angle. Therefore, the electric conductivity of the SWCNT is variable between that of a metal and that of a semiconductor.
  • the SWCNT is believed to have a feature similar to one-dimensional electric conductivity.
  • the SWCNT is applicable to a filament having a nanostructure.
  • the SWCNT must be deformed into a desired shape.
  • a technique of selectively deforming the SWCNT is expected to be useful in application to micromachines and in facilitating the preparation of high-resolution probes (see H. Dai et al “Nanotubes as nanoprobes in scanning probe microscopy”, Nature, Vol. 384, pp. 147-150 (1996) and S. S. Wong et al “Covalently functionalized nanotubes as nanometre-sized probes in chemistry and biology”, Nature, Vol. 394, pp. 52-55 (1998)).
  • a technique of selectively feeding an electric current to the filament having a nanostructure shows a possibility of development of electronic devices having a microstructure (S. J. Tans et al “Room-temperature transistor based on a single carbon nanotube”, Nature, Vol. 393, pp. 49-52 (1998)).
  • this technique is useful as one of the high-resolution techniques in analysis evaluation.
  • this field of technique is highly expected.
  • the filament comprises a plurality of SWCNT filaments scattered over a plurality of electrodes formed on a substrate. By applying a predetermined voltage between the electrodes, electrons are emitted from the filaments.
  • the above-mentioned filament is advantageous in the following respects. Specifically, heating is unnecessary so that energy efficiency is high.
  • the filament comprises carbon atoms alone and is manufactured at a low cost. In recent years, much attention is directed to this field of technique.
  • a method of producing a heterojunction of a carbon nanotube and carbide wherein a part of the carbon nanotube is contacted with a reactive substance to cause reaction of the carbon nanotube and the reactive substance by solid-solid diffusion.
  • the reaction of the carbon nanotube is restricted to a contacting area where the carbon nanotube is contacted with the reactive substance and an adjacent zone around the contacting area.
  • the carbon nanotube is not changed in structure. Therefore, it is possible to form a heterojunction of the carbon nanotube and carbide.
  • a filament comprising a filament material which is deformed by irradiation of electromagnetic wave to at least a part thereof.
  • the filament material is a nanotube.
  • the nanotube is a single-wall nanotube.
  • the nanotube has a bundled structure.
  • the nanotube is a carbon nanotube.
  • a method of inducing an electric current in a filament comprising the step of irradiating at least a part of a filament material with electromagnetic wave to selectively induce the electric current in the filament material.
  • a method of working a filament comprising the step of irradiating at least a part of a filament material with electromagnetic wave to deform the filament material.
  • the electromagnetic wave is visible light.
  • FIGS. 1A and 1B are schematic views for describing a method of forming a heterojunction according to this invention
  • FIG. 2A is an electron micrograph showing a heterojunction of a bundle of a plurality of single-wall carbon nanotubes and SiC;
  • FIG. 2B is an electron micrograph showing a heterojunction of a single-wall carbon nanotube and SiC.
  • FIGS. 3A and 3B are optical micrographs for describing a method of working a filament according to one embodiment of this invention.
  • FIGS. 4A and 4B are optical micrographs showing deformation of the filament illustrated in FIGS. 3A and 3B at different levels of irradiation energy
  • FIG. 5 is an optical micrograph showing the filament illustrated in FIGS. 3A and 3B irradiated with a laser beam
  • FIG. 6 is a view showing the result of measurement of an electric current induced in the filament illustrated in FIG. 5 .
  • a reactive substance use is made of a metal such as Ti, W, Mo, V, Fe, and Nb or a semiconductor such as Si.
  • a metal such as Ti, W, Mo, V, Fe, and Nb or a semiconductor such as Si.
  • a part of a carbon nanotube is contacted with the reactive substance.
  • the reactive substance is held in a vacuum or an inactive gas. At least the reactive substance is heated to diffuse the reactive substance towards the carbon nanotube. Thus, the reaction between the carbon nanotube and the reactive substance proceeds.
  • a heterojunction of a single-wall carbon nanotube and SiC was formed by the use of single crystal silicon as a reactive substance.
  • a (111) plane silicon wafer was cut into a dimension of about 7 mm long and about 3 mm wide in a direction perpendicular to a substrate.
  • mechanical polishing was performed until the thickness of a center portion is reduced to the order of several tens of microns.
  • chemical etching was performed until the thickness is further reduced to the order of several tens of nanometers.
  • a silicon substrate 1 was prepared.
  • An oxide film on the surface of the silicon substrate was removed by chemical etching.
  • a number of single-wall carbon nanotubes 2 prepared by laser ablation were dispersed in ethanol and put on the silicon substrate 1 prepared as described above. In this event, most of the carbon nanotubes 2 were extended, heavily bent, or bundled together. After ethanol was evaporated from the silicon substrate 1 , each of the carbon nanotube 2 was placed on the silicon substrate 1 with its three-dimensional structure maintained. As a result, the silicon substrate 1 and the carbon nanotube 2 were partially contacted in a small area ( FIG. 1A ). Thus, a sample was prepared.
  • the sample was mounted on a heating stage of a ultra-high-vacuum transmission electron microscope (UHV-TEM, JEM-2000FXVII).
  • UHV-TEM ultra-high-vacuum transmission electron microscope
  • JEM-2000FXVII ultra-high-vacuum transmission electron microscope
  • the silicon substrate 1 was directly supplied with an electric current to heat the sample. As a result of measurement by a pyrometer, the highest temperature of the silicon substrate 1 was about 1000° C. When the temperature became higher than about 800° C., surface migration of silicon was observed.
  • FIG. 1B transmission electron microscope
  • Heating was carried out for different heating periods controllably varied within a range from several minutes to one hour. However, no difference in appearance was observed in dependence upon the heating periods.
  • the heterojunction of the single-wall carbon nanotube and SiC thus obtained was shown in each of FIGS. 2A and 2B as a micrograph taken by the TEM.
  • FIG. 2A shows the heterojunction of a bundle of a plurality of single-wall carbon nanotubes and SiC while FIG. 2B shows the heterojunction of one single-wall carbon nanotube and SiC.
  • heating was performed by feeding the electric current to the substrate.
  • the electric current may be supplied between the carbon nanotube and the substrate.
  • use may be made of any other heating means such as infrared radiation.
  • the heating may be performed not only in the vacuum but also in an argon or a nitrogen atmosphere.
  • the method according to this invention comprises the step of partially contacting the carbon nanotube with the reactive substance to cause the reaction between carbon nanotube and the reactive substance by solid-solid diffusion of the reactive substance.
  • the filament having a nanostructure comprises a filament material on the order of nanometers. At least a part of the filament material is irradiated with electromagnetic wave such as visible light to deform the filament material into a desired shape, for example, an arcuate shape or a ⁇ shape.
  • NT nanotube
  • SWCNT single-wall carbon nanotube
  • a SWCNT as the filament material is formed by laser ablation known in the art (see Y. Zhang et al “Microscopic structure of as-grown single-wall carbon nanotubes by laser ablation”, Philosophical Magazine Letters, Vol. 78, No. 2, pp. 139-144 (1998)).
  • a graphite target containing 1.2at % of Ni and Co as catalysts was placed in a furnace heated to 1200° C., kept at a pressure of 500 Torr, and supplied with an Ar gas at a flow rate of about 300 sccm.
  • the graphite target was irradiated with second harmonic produced by the YAG laser to obtain the SWCNT.
  • the second-order harmonic wave has a pulse width of about 8 ns and energy per pulse of about 3J/cm 2 .
  • the SWCNT was put in a sample cell having a quartz window with two electrodes arranged inside.
  • the sample cell Within the sample cell, the SWCNT guided by a stream of the Ar gas was caught between the electrodes. Thereafter, the sample cell is evacuated to a pressure of 0.1 Torr.
  • the SWCNT was irradiated through the quartz window of the sample cell with visible light emitted from a halogen lamp of 150 W to obtain a filament deformed into a desired shape.
  • the filament before and after irradiation of the visible light is shown, respectively.
  • the visible light had irradiation energy of about 20 mW/cm 2 .
  • the filament can be deformed into a desired shape by simply irradiating the filament with the visible light.
  • the deformation of the filament can be controlled by selecting the irradiation energy of the visible light and the irradiation area of the filament.
  • the deformation of the filament is dependent upon the level of the irradiation energy.
  • the visible light had the irradiation energy of 30 mW/cm 2 .
  • the visible light had the irradiation energy of 5 mW/cm 2 .
  • the deformation of the filament apparently depends upon the level of the irradiation energy.
  • the filament was irradiated with a laser beam having a wavelength of 632 nm and irradiation energy of about 800 mW/cm 2 by the use of a He—Ne laser.
  • the deformation of the filament was substantially equivalent to that of the filament illustrated in FIG. 4A .
  • an electric current was induced in the filament when the filament was irradiated at the center between two electrodes with a laser beam having a wavelength of 632 nm and irradiation energy of about 800 mW/cm 2 by the use of a He—Ne laser.
  • the result of measurement of the electric current is illustrated in the figure.
  • the operation is very simple and convenient.
  • the filament can be applied as a nanoelectronics element.
  • the halogen lamp and the He—Ne laser are used in the foregoing embodiment.
  • similar effect is achieved by the use of any other light or energy source.

Abstract

A carbon nanotube is contacted with a reactive substance which is a metal or a semiconductor. The reactive substance is heated to diffuse atoms of the reactive substance into the carbon nanotube so that the carbon nanotube is partially transformed or converted into carbide as a reaction product. Thus, a heterojunction of the reaction product and the carbon nanotube is formed. For example, the carbon nanotube (2) is contacted with a silicon substrate (1). The silicon substrate (1) is heated to cause solid-solid diffusion of Si. As a result, SiC (3) is formed as the heterojunction. At least a part of a filament material of a carbon nanotube is irradiated with electromagnetic wave to deform the filament material.

Description

    BACKGROUND OF THE INVENTION
  • This invention relates to a method of forming a heterojunction of a carbon nanotube and a different material and, in particular, to a method of forming a heterojunction of a carbon nanotube and carbide.
  • This invention relates also to a filament, a method of inducing an electric current therein, and a method of working the same and, in particular, to a filament having a nanostructure and adapted for use in a micromachine and an electron source, a method of inducing an electric current therein, and a method of working the same.
  • A so-called heterojunction formed by heterogeneous or different materials is an important structure in order to utilize material-specific characteristics in an electronic device.
  • A carbon nanotube comprises a graphite sheet composed of six-member carbon rings and has a cylindrical structure formed by rolling the graphite sheet in a manner such that the six-member carbon rings are aligned in a helical fashion.
  • The carbon nanotube, together with a spherical fullerene represented by C60, is expected as a useful material for an electronic device because of its specific electric characteristics. Particularly, attention is directed to a bond of the carbon nanotube and carbide.
  • This is because carbide itself has very interesting electric characteristics. For example, SiC has semiconducting features. TiC has metallic features. Fe3C acts as a ferromagnetic material. NbC attracts the attention as a superconducting material. BCx, serves as an insulator. Thus, carbide has a wide variety of electric characteristics.
  • On the other hand, a single-wall carbon nanotube has specific electric characteristics. That is, the single-wall carbon nanotube acts as a semiconductor or a metal in dependence upon a diameter and a helical condition (an angle formed between an axial direction of the nanotube and an aligning direction of carbon atoms) (M. S. Dresselhaus et al “Science of Fullerenes and Carbon Nanotubes” (Academic Press, New York, 1996)). It is expected that various functional devices can be achieved by a combination of carbide and the carbon nanotube.
  • However, no conventional technique exists to form such heterojunction of carbide and the carbon nanotube. This is because the carbon nanotube has a very high Young's modulus and is therefore difficult to be mechanically processed or deformed.
  • In order to produce a carbide nanorod using the carbon nanotube as a starting material, use has been made of a technique of contacting a multiwall carbon nanotube with volatile oxide such as SiO and B2O2 or halide such as SiI4, TiI4, NbI4, and FeCl3 to cause high-temperature reaction (H. Dai et al “Synthesis and characterization of carbide nanorods”, Nature, Vol. 375, pp. 769-772, (1995); D. Zhou et al “Production of silicon carbide whiskers from carbon nanoclusters”, Chem. Phys. Lett., Vol. 222, pp. 233-238 (1994); W. Han et al “Continuous synthesis and characterization of silicon carbide nanorods”, Chem. Phys. Lett., Vol. 265, pp. 374-378 (1997)). Another technique is disclosed in EP 60388 A2 (1993) in which carbon fiber is transformed or converted into a SiC rod by the use of SiO vapor.
  • In the above-mentioned techniques of producing the carbide nanorod by the use of vapor-solid reaction, the carbon nanotube is exposed to reactive vapor to transform a whole of the carbon nanotube into carbide. Therefore, those techniques can not be applied to formation of the heterojunction. In other words, in order to realize the heterojunction, a part of the carbon nanotube must be selectively transformed into carbide with a remaining part protected from the reaction. However, no conventional technique can achieve such selective reaction.
  • Since a single-wall carbon nanotube (SWCNT) having a nanostructure has been discovered (Iijima et al, “Pentagons, heptagons and negative curvature in graphite microtubule growth”, Nature, vol. 356, p776, (1992)), physical properties of the SWCNT are gradually revealed and research and development for practical applications are actively carried out.
  • The SWCNT comprises a hexagonal network graphite plane rolled into a cylindrical shape. The SWCNT has an electron structure widely varied depending upon a tube diameter and a chiral angle. Therefore, the electric conductivity of the SWCNT is variable between that of a metal and that of a semiconductor. The SWCNT is believed to have a feature similar to one-dimensional electric conductivity.
  • For example, the SWCNT is applicable to a filament having a nanostructure. For use as the filament, the SWCNT must be deformed into a desired shape. A technique of selectively deforming the SWCNT is expected to be useful in application to micromachines and in facilitating the preparation of high-resolution probes (see H. Dai et al “Nanotubes as nanoprobes in scanning probe microscopy”, Nature, Vol. 384, pp. 147-150 (1996) and S. S. Wong et al “Covalently functionalized nanotubes as nanometre-sized probes in chemistry and biology”, Nature, Vol. 394, pp. 52-55 (1998)).
  • On the other hand, a technique of selectively feeding an electric current to the filament having a nanostructure, such as the SWCNT, shows a possibility of development of electronic devices having a microstructure (S. J. Tans et al “Room-temperature transistor based on a single carbon nanotube”, Nature, Vol. 393, pp. 49-52 (1998)). In addition, this technique is useful as one of the high-resolution techniques in analysis evaluation. Thus, this field of technique is highly expected.
  • To meet such expectation, proposal is made of a filament of a field emission type (Jean-Marc Bonard et al “Field emission from single-wall carbon nanotube films”, Appl. Phys. Lett. Vol. 73, pp. 918-920 (1998)). The filament comprises a plurality of SWCNT filaments scattered over a plurality of electrodes formed on a substrate. By applying a predetermined voltage between the electrodes, electrons are emitted from the filaments.
  • As compared with a typical thermionic emission type, the above-mentioned filament is advantageous in the following respects. Specifically, heating is unnecessary so that energy efficiency is high. The filament comprises carbon atoms alone and is manufactured at a low cost. In recent years, much attention is directed to this field of technique.
  • In order to individually and selectively deform the filament, for example, a manipulation technique is necessary. Manipulation of those filaments using the SWCNTs and having a nanostructure requires high resolution comparable to that required in manipulation of atoms. Therefore, it is in fact impossible to selectively deform the filament.
  • In addition, there is no existing technique of selectively inducing an electric current in the filament of a nanostructure. Thus, it is impossible to selectively induce the electric current in the filament using the SWCNT having a nanostructure.
    • SUMMARY OF THE INVENTION
  • It is therefore an object of this invention to provide a method of forming a heterojunction of a carbon nanotube and carbide, which is useful for an electronic device.
  • It is therefore an object of this invention to provide a filament such as a SWCNT having a nanostructure which can be individually and selectively deformed into a desired shape.
  • It is another object of this invention to provide a filament such as a SWCNT having a nanostructure in which an electric current can be selectively induced.
  • It is still another object of this invention to provide a method of inducing an electric current in the above-mentioned filament.
  • It is yet another object of this invention to provide a method of selectively deforming the filament.
  • According to this invention, there is provided a method of producing a heterojunction of a carbon nanotube and carbide, wherein a part of the carbon nanotube is contacted with a reactive substance to cause reaction of the carbon nanotube and the reactive substance by solid-solid diffusion.
  • With the above-mentioned method, the reaction of the carbon nanotube is restricted to a contacting area where the carbon nanotube is contacted with the reactive substance and an adjacent zone around the contacting area. In a most part of a noncontacting area, the carbon nanotube is not changed in structure. Therefore, it is possible to form a heterojunction of the carbon nanotube and carbide.
  • According to this invention, there is provided a filament comprising a filament material which is deformed by irradiation of electromagnetic wave to at least a part thereof.
  • Preferably, the filament material is a nanotube.
  • Preferably, the nanotube is a single-wall nanotube.
  • Preferably, the nanotube has a bundled structure.
  • Preferably, the nanotube is a carbon nanotube.
  • According to this invention, there is provided a method of inducing an electric current in a filament, comprising the step of irradiating at least a part of a filament material with electromagnetic wave to selectively induce the electric current in the filament material.
  • According to this invention, there is provided a method of working a filament, comprising the step of irradiating at least a part of a filament material with electromagnetic wave to deform the filament material.
  • Preferably, the electromagnetic wave is visible light.
    • BRIEF DESCRIPTION OF THE DRAWING
  • FIGS. 1A and 1B are schematic views for describing a method of forming a heterojunction according to this invention;
  • FIG. 2A is an electron micrograph showing a heterojunction of a bundle of a plurality of single-wall carbon nanotubes and SiC; and
  • FIG. 2B is an electron micrograph showing a heterojunction of a single-wall carbon nanotube and SiC.
  • FIGS. 3A and 3B are optical micrographs for describing a method of working a filament according to one embodiment of this invention;
  • FIGS. 4A and 4B are optical micrographs showing deformation of the filament illustrated in FIGS. 3A and 3B at different levels of irradiation energy;
  • FIG. 5 is an optical micrograph showing the filament illustrated in FIGS. 3A and 3B irradiated with a laser beam; and
  • FIG. 6 is a view showing the result of measurement of an electric current induced in the filament illustrated in FIG. 5.
    • DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • Now, description will be made about a preferred embodiment of this invention with reference to the drawing.
  • As a reactive substance, use is made of a metal such as Ti, W, Mo, V, Fe, and Nb or a semiconductor such as Si. A part of a carbon nanotube is contacted with the reactive substance. Preferably, the reactive substance is held in a vacuum or an inactive gas. At least the reactive substance is heated to diffuse the reactive substance towards the carbon nanotube. Thus, the reaction between the carbon nanotube and the reactive substance proceeds.
    • Embodiment
  • A heterojunction of a single-wall carbon nanotube and SiC was formed by the use of single crystal silicon as a reactive substance. At first, a (111) plane silicon wafer was cut into a dimension of about 7 mm long and about 3 mm wide in a direction perpendicular to a substrate. Thereafter, mechanical polishing was performed until the thickness of a center portion is reduced to the order of several tens of microns. Then, chemical etching was performed until the thickness is further reduced to the order of several tens of nanometers. Thus, a silicon substrate 1 was prepared. As an etchant, a mixed solution of HF and HNO3 (HF:HNO3=1:4) was used. An oxide film on the surface of the silicon substrate was removed by chemical etching.
  • A number of single-wall carbon nanotubes 2 prepared by laser ablation were dispersed in ethanol and put on the silicon substrate 1 prepared as described above. In this event, most of the carbon nanotubes 2 were extended, heavily bent, or bundled together. After ethanol was evaporated from the silicon substrate 1, each of the carbon nanotube 2 was placed on the silicon substrate 1 with its three-dimensional structure maintained. As a result, the silicon substrate 1 and the carbon nanotube 2 were partially contacted in a small area (FIG. 1A). Thus, a sample was prepared.
  • Then, the sample was mounted on a heating stage of a ultra-high-vacuum transmission electron microscope (UHV-TEM, JEM-2000FXVII). A vacuum chamber was evacuated to a pressure between 10-9 and 10-8 Torr.
  • The silicon substrate 1 was directly supplied with an electric current to heat the sample. As a result of measurement by a pyrometer, the highest temperature of the silicon substrate 1 was about 1000° C. When the temperature became higher than about 800° C., surface migration of silicon was observed.
  • By observation through the transmission electron microscope (TEM), it was confirmed that heating for several minutes caused local reaction of silicon and the single-wall carbon nanotube to produce SiC 3 (FIG. 1B). Heating was carried out for different heating periods controllably varied within a range from several minutes to one hour. However, no difference in appearance was observed in dependence upon the heating periods. The heterojunction of the single-wall carbon nanotube and SiC thus obtained was shown in each of FIGS. 2A and 2B as a micrograph taken by the TEM. FIG. 2A shows the heterojunction of a bundle of a plurality of single-wall carbon nanotubes and SiC while FIG. 2B shows the heterojunction of one single-wall carbon nanotube and SiC.
  • Although the preferred embodiment has been described in the foregoing, this invention is not restricted thereto but can be modified in various manners within the scope of this invention. For example, not only the single-wall carbon nanotube but also a multiwall carbon nanotube can be used. In the foregoing embodiment, heating was performed by feeding the electric current to the substrate. Alternatively, the electric current may be supplied between the carbon nanotube and the substrate. Instead of the electric current, use may be made of any other heating means such as infrared radiation. The heating may be performed not only in the vacuum but also in an argon or a nitrogen atmosphere.
  • As described above, the method according to this invention comprises the step of partially contacting the carbon nanotube with the reactive substance to cause the reaction between carbon nanotube and the reactive substance by solid-solid diffusion of the reactive substance. Thus, by the above-mentioned method which is very simple, it is possible to selectively form the heterojunction between a part of the carbon nanotube and carbide. The heterojunction of the carbon nanotube and carbide achieved by this invention is useful in formation of electronic devices and will make a great contribution to electronic industry.
  • Now, description will be made about a filament according to one embodiment of this invention as well as a method of inducing an electric current in the filament and a method of working the filament.
  • The filament having a nanostructure comprises a filament material on the order of nanometers. At least a part of the filament material is irradiated with electromagnetic wave such as visible light to deform the filament material into a desired shape, for example, an arcuate shape or a η shape.
  • As the filament material, use is advantageously made of a nanotube (NT), particularly, a single-wall carbon nanotube (SWCNT) or a plurality of SWCNTs in a bundled structure.
  • Next, the method of working the filament will be described.
  • At first, a SWCNT as the filament material is formed by laser ablation known in the art (see Y. Zhang et al “Microscopic structure of as-grown single-wall carbon nanotubes by laser ablation”, Philosophical Magazine Letters, Vol. 78, No. 2, pp. 139-144 (1998)).
  • Specifically, a graphite target containing 1.2at % of Ni and Co as catalysts was placed in a furnace heated to 1200° C., kept at a pressure of 500 Torr, and supplied with an Ar gas at a flow rate of about 300 sccm. By the use of a Nd-doped YAG (yttrium-aluminum-garnet) laser, the graphite target was irradiated with second harmonic produced by the YAG laser to obtain the SWCNT. The second-order harmonic wave has a pulse width of about 8 ns and energy per pulse of about 3J/cm2.
  • Then, the SWCNT was put in a sample cell having a quartz window with two electrodes arranged inside.
  • Within the sample cell, the SWCNT guided by a stream of the Ar gas was caught between the electrodes. Thereafter, the sample cell is evacuated to a pressure of 0.1 Torr.
  • Next, the SWCNT was irradiated through the quartz window of the sample cell with visible light emitted from a halogen lamp of 150 W to obtain a filament deformed into a desired shape.
  • Referring to FIGS. 3A and 3B, the filament before and after irradiation of the visible light is shown, respectively. Herein, the visible light had irradiation energy of about 20 mW/cm2.
  • As will be understood from FIGS. 3A and 3B, the filament can be deformed into a desired shape by simply irradiating the filament with the visible light. The deformation of the filament can be controlled by selecting the irradiation energy of the visible light and the irradiation area of the filament.
  • Referring to FIGS. 4A and 4B, the deformation of the filament is dependent upon the level of the irradiation energy. In FIG. 4A, the visible light had the irradiation energy of 30 mW/cm2. In FIG. 4B, the visible light had the irradiation energy of 5 mW/cm2.
  • As seen from FIGS. 4A and 4B, the deformation of the filament apparently depends upon the level of the irradiation energy.
  • Referring to FIG. 5, the filament was irradiated with a laser beam having a wavelength of 632 nm and irradiation energy of about 800 mW/cm2 by the use of a He—Ne laser. The deformation of the filament was substantially equivalent to that of the filament illustrated in FIG. 4A.
  • Referring to FIG. 6, an electric current was induced in the filament when the filament was irradiated at the center between two electrodes with a laser beam having a wavelength of 632 nm and irradiation energy of about 800 mW/cm2 by the use of a He—Ne laser. The result of measurement of the electric current is illustrated in the figure.
  • As seen from FIG. 6, it is possible to selectively induce the electric current in the filament by irradiating the filament with the laser beam.
  • According to this embodiment, it is possible to individually and selectively deform the filament of a nanostructure such as SWCNT by irradiating the filament with electromagnetic wave such as visible light.
  • It is also possible to induce the electric current in the filament by irradiating the filament with electromagnetic wave such as visible light.
  • In each of the above-mentioned operations, it is sufficient to simply irradiate at least a part of the filament with the electromagnetic wave such as visible light. Thus, the operation is very simple and convenient. The filament can be applied as a nanoelectronics element.
  • In the foregoing, description has been made about one embodiment of the filament, the method of inducing the electric current in the filament, and the method of working the filament. However, this invention is not restricted to the foregoing embodiment but can be modified in various manners within the scope of this invention.
  • For example, the halogen lamp and the He—Ne laser are used in the foregoing embodiment. However, similar effect is achieved by the use of any other light or energy source.
  • As described above, according to this invention, it is possible to individually and selectively deform the filament of a nanostructure such as the SWCNT into a desired shape.
  • By irradiating the filament with electromagnetic wave such as visible light, it is possible to selectively induce the electric current in the filament.

Claims (3)

1. A method of working a filament material, comprising the step of irradiating at least a part of said filament material with electromagnetic wave to deform said filament material.
2. A method as claimed in claim 1, wherein said electromagnetic wave is visible light.
3. A method as claimed in claim 1, wherein said filament material is of a carbon nanotube.
US11/671,883 1998-06-08 2007-02-06 Method of forming a heterojunction of a carbon nanotube and a different material, method of working a filament of a nanotube Abandoned US20070128101A1 (en)

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JP14704199A JP3518422B2 (en) 1999-04-16 1999-04-16 Filament, current inducing method therefor and processing method thereof
JP1999-147041 1999-04-16
US09/327,510 US6203864B1 (en) 1998-06-08 1999-06-08 Method of forming a heterojunction of a carbon nanotube and a different material, method of working a filament of a nanotube
US09/736,220 US20010001681A1 (en) 1998-06-08 2000-12-15 Method of forming a heterojunction of a carbon nanotube and a different material, method of working a filament of a nanotube
US10/623,659 US20040124755A1 (en) 1998-06-08 2003-07-22 Method of forming a heterojunction of a carbon nanotube and a different material, method of working a filament of a nanotube
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9786848B2 (en) 2010-10-14 2017-10-10 University Of Utah Research Foundation Nanofiber-based heterojunction approach for high photoconductivity on organic materials

Families Citing this family (86)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6700550B2 (en) 1997-01-16 2004-03-02 Ambit Corporation Optical antenna array for harmonic generation, mixing and signal amplification
JP3077655B2 (en) * 1997-12-22 2000-08-14 日本電気株式会社 Apparatus and method for producing carbon nanotube
US6593166B1 (en) 1998-03-24 2003-07-15 Silverbrook Research Pty Ltd Method for construction of nanotube matrix material
US6514897B1 (en) * 1999-01-12 2003-02-04 Hyperion Catalysis International, Inc. Carbide and oxycarbide based compositions, rigid porous structures including the same, methods of making and using the same
US7576027B2 (en) * 1999-01-12 2009-08-18 Hyperion Catalysis International, Inc. Methods of making carbide and oxycarbide containing catalysts
US6280697B1 (en) * 1999-03-01 2001-08-28 The University Of North Carolina-Chapel Hill Nanotube-based high energy material and method
AU782000B2 (en) * 1999-07-02 2005-06-23 President And Fellows Of Harvard College Nanoscopic wire-based devices, arrays, and methods of their manufacture
US20050181209A1 (en) * 1999-08-20 2005-08-18 Karandikar Prashant G. Nanotube-containing composite bodies, and methods for making same
US20060175601A1 (en) * 2000-08-22 2006-08-10 President And Fellows Of Harvard College Nanoscale wires and related devices
EP1314189B1 (en) * 2000-08-22 2013-02-27 President and Fellows of Harvard College Electrical device comprising doped semiconductor nanowires and method for its production
US7301199B2 (en) 2000-08-22 2007-11-27 President And Fellows Of Harvard College Nanoscale wires and related devices
JP3610325B2 (en) * 2000-09-01 2005-01-12 キヤノン株式会社 Electron emitting device, electron source, and method of manufacturing image forming apparatus
AU2904602A (en) 2000-12-11 2002-06-24 Harvard College Nanosensors
US6423583B1 (en) * 2001-01-03 2002-07-23 International Business Machines Corporation Methodology for electrically induced selective breakdown of nanotubes
WO2002093738A2 (en) * 2001-01-19 2002-11-21 California Institute Of Technology Carbon nanobimorph actuator and sensor
DE10118405A1 (en) * 2001-04-12 2002-10-24 Infineon Technologies Ag Heterostructure component used in electronic devices comprises a single hetero-nanotube having regions made from nanotube materials having different energy band gaps value
WO2002088025A1 (en) * 2001-04-26 2002-11-07 New York University Method for dissolving carbon nanotubes
US7341498B2 (en) * 2001-06-14 2008-03-11 Hyperion Catalysis International, Inc. Method of irradiating field emission cathode having nanotubes
US6706402B2 (en) * 2001-07-25 2004-03-16 Nantero, Inc. Nanotube films and articles
US6924538B2 (en) * 2001-07-25 2005-08-02 Nantero, Inc. Devices having vertically-disposed nanofabric articles and methods of making the same
US6574130B2 (en) * 2001-07-25 2003-06-03 Nantero, Inc. Hybrid circuit having nanotube electromechanical memory
US7259410B2 (en) * 2001-07-25 2007-08-21 Nantero, Inc. Devices having horizontally-disposed nanofabric articles and methods of making the same
US6919592B2 (en) * 2001-07-25 2005-07-19 Nantero, Inc. Electromechanical memory array using nanotube ribbons and method for making same
US6835591B2 (en) * 2001-07-25 2004-12-28 Nantero, Inc. Methods of nanotube films and articles
US7566478B2 (en) * 2001-07-25 2009-07-28 Nantero, Inc. Methods of making carbon nanotube films, layers, fabrics, ribbons, elements and articles
US6643165B2 (en) 2001-07-25 2003-11-04 Nantero, Inc. Electromechanical memory having cell selection circuitry constructed with nanotube technology
US6784028B2 (en) * 2001-12-28 2004-08-31 Nantero, Inc. Methods of making electromechanical three-trace junction devices
US7176505B2 (en) * 2001-12-28 2007-02-13 Nantero, Inc. Electromechanical three-trace junction devices
US7162302B2 (en) * 2002-03-04 2007-01-09 Nanoset Llc Magnetically shielded assembly
US20040225213A1 (en) * 2002-01-22 2004-11-11 Xingwu Wang Magnetic resonance imaging coated assembly
US6846985B2 (en) 2002-01-22 2005-01-25 Nanoset, Llc Magnetically shielded assembly
US20050260331A1 (en) * 2002-01-22 2005-11-24 Xingwu Wang Process for coating a substrate
DE10204895B4 (en) * 2002-02-06 2004-07-29 Diehl Munitionssysteme Gmbh & Co. Kg Process for the production of reactive substances
DE60301582T2 (en) * 2002-02-09 2006-06-22 Samsung Electronics Co., Ltd., Suwon Carbon nanotube storage device and method of manufacturing the storage device
AU2003215253A1 (en) * 2002-02-19 2003-09-09 Rensselaer Polytechnic Institute Method of transforming carbon nanotubes
US6515325B1 (en) * 2002-03-06 2003-02-04 Micron Technology, Inc. Nanotube semiconductor devices and methods for making the same
US6774333B2 (en) * 2002-03-26 2004-08-10 Intel Corporation Method and system for optically sorting and/or manipulating carbon nanotubes
US7335395B2 (en) * 2002-04-23 2008-02-26 Nantero, Inc. Methods of using pre-formed nanotubes to make carbon nanotube films, layers, fabrics, ribbons, elements and articles
AU2003261205A1 (en) 2002-07-19 2004-02-09 President And Fellows Of Harvard College Nanoscale coherent optical components
US6815323B1 (en) 2003-01-10 2004-11-09 The United States Of America As Represented By The Secretary Of The Air Force Ohmic contacts on n-type silicon carbide using carbon films
US7560136B2 (en) * 2003-01-13 2009-07-14 Nantero, Inc. Methods of using thin metal layers to make carbon nanotube films, layers, fabrics, ribbons, elements and articles
US20040180244A1 (en) * 2003-01-24 2004-09-16 Tour James Mitchell Process and apparatus for microwave desorption of elements or species from carbon nanotubes
US6764874B1 (en) * 2003-01-30 2004-07-20 Motorola, Inc. Method for chemical vapor deposition of single walled carbon nanotubes
US20050155779A1 (en) * 2003-04-08 2005-07-21 Xingwu Wang Coated substrate assembly
US7910064B2 (en) * 2003-06-03 2011-03-22 Nanosys, Inc. Nanowire-based sensor configurations
KR20060058085A (en) * 2003-07-08 2006-05-29 큐나노 에이비 Probe structures incorporating nanowhiskers, production methods thereof, and methods of forming nanowhiskers
CN101410927B (en) * 2003-07-09 2011-09-14 海珀里昂催化国际有限公司 Field emission devices made with laser and/or plasma treated carbon nanotube mats, films or inks
US7277460B1 (en) * 2003-08-14 2007-10-02 Ionatron Generation of optical filaments by use of localized optical inhomogeneities
EP1508926A1 (en) * 2003-08-19 2005-02-23 Hitachi, Ltd. Nanotube transistor device
JP2007515364A (en) * 2003-10-16 2007-06-14 ザ ユニバーシティ オブ アクロン Carbon nanotubes on carbon nanofiber substrate
JP2005128771A (en) * 2003-10-23 2005-05-19 Fujitsu Ltd Data file system, data access server, and data access program
WO2006001834A2 (en) * 2003-12-31 2006-01-05 Pettit John W Passive optical sensor using carbon nanotubes
US20090227107A9 (en) * 2004-02-13 2009-09-10 President And Fellows Of Havard College Nanostructures Containing Metal Semiconductor Compounds
US20060062985A1 (en) * 2004-04-26 2006-03-23 Karandikar Prashant G Nanotube-containing composite bodies, and methods for making same
US20050238810A1 (en) * 2004-04-26 2005-10-27 Mainstream Engineering Corp. Nanotube/metal substrate composites and methods for producing such composites
WO2006107312A1 (en) * 2004-06-15 2006-10-12 President And Fellows Of Harvard College Nanosensors
US20060051281A1 (en) * 2004-09-09 2006-03-09 Bhabendra Pradhan Metal carbides and process for producing same
US20070240757A1 (en) * 2004-10-15 2007-10-18 The Trustees Of Boston College Solar cells using arrays of optical rectennas
US7348592B2 (en) * 2004-11-29 2008-03-25 The United States Of America As Represented By The Secretary Of The Navy Carbon nanotube apparatus and method of carbon nanotube modification
KR20070101857A (en) 2004-12-06 2007-10-17 더 프레지던트 앤드 펠로우즈 오브 하바드 칼리지 Nanoscale wire-based data storage
US7569850B2 (en) * 2005-01-24 2009-08-04 Lawrence Livermore National Security, Llc Lipid bilayers on nano-templates
US7544978B2 (en) * 2005-01-24 2009-06-09 Lawrence Livermore National Security, Llc Lipid nanotube or nanowire sensor
US20100227382A1 (en) * 2005-05-25 2010-09-09 President And Fellows Of Harvard College Nanoscale sensors
WO2006132659A2 (en) * 2005-06-06 2006-12-14 President And Fellows Of Harvard College Nanowire heterostructures
CN100417117C (en) * 2005-06-15 2008-09-03 华为技术有限公司 Method for recognizing node accessibility in automatically switched optical network
US7589880B2 (en) * 2005-08-24 2009-09-15 The Trustees Of Boston College Apparatus and methods for manipulating light using nanoscale cometal structures
US7754964B2 (en) * 2005-08-24 2010-07-13 The Trustees Of Boston College Apparatus and methods for solar energy conversion using nanocoax structures
US7649665B2 (en) * 2005-08-24 2010-01-19 The Trustees Of Boston College Apparatus and methods for optical switching using nanoscale optics
US7623746B2 (en) * 2005-08-24 2009-11-24 The Trustees Of Boston College Nanoscale optical microscope
JP2009506546A (en) 2005-08-24 2009-02-12 ザ トラスティーズ オブ ボストン カレッジ Apparatus and method for solar energy conversion using nanoscale co-metallic structures
JP2009540333A (en) 2006-06-12 2009-11-19 プレジデント アンド フェロウズ オブ ハーバード カレッジ Nanosensors and related technologies
CN101093764B (en) * 2006-06-23 2012-03-28 清华大学 Field emission component, and preparation method
WO2008033303A2 (en) 2006-09-11 2008-03-20 President And Fellows Of Harvard College Branched nanoscale wires
JP5009993B2 (en) 2006-11-09 2012-08-29 ナノシス・インク． Nanowire arrangement method and deposition method
WO2008127314A1 (en) 2006-11-22 2008-10-23 President And Fellows Of Harvard College High-sensitivity nanoscale wire sensors
JP4825697B2 (en) * 2007-01-25 2011-11-30 株式会社ミツトヨ Digital displacement measuring instrument
WO2008094517A1 (en) * 2007-01-30 2008-08-07 Solasta, Inc. Photovoltaic cell and method of making thereof
EP2115784A2 (en) * 2007-02-12 2009-11-11 Solasta, Inc. Photovoltaic cell with reduced hot-carrier cooling
US7892610B2 (en) * 2007-05-07 2011-02-22 Nanosys, Inc. Method and system for printing aligned nanowires and other electrical devices
US20090007956A1 (en) * 2007-07-03 2009-01-08 Solasta, Inc. Distributed coax photovoltaic device
WO2010115007A1 (en) * 2009-04-03 2010-10-07 Board Of Trustees Of The University Of Arkansas Photovoltaic device using single wall carbon nanotubes and method of fabricating the same
US20120135158A1 (en) 2009-05-26 2012-05-31 Sharp Kabushiki Kaisha Methods and systems for electric field deposition of nanowires and other devices
US8673445B2 (en) * 2009-07-17 2014-03-18 Nissei Plastic Industrial Co. Ltd. Composite-plated article and method for producing same
WO2011038228A1 (en) 2009-09-24 2011-03-31 President And Fellows Of Harvard College Bent nanowires and related probing of species
ES2362229B1 (en) * 2009-12-16 2012-05-09 Consejo Superior De Investigaciones Cientificas (Csic) (50%) ELECTROCONDUCTOR COMPOSITE MATERIAL WITH CONTROLLED THERMAL EXPANSION COEFFICIENT.
CN108217578A (en) * 2017-12-18 2018-06-29 中国科学院物理研究所 A kind of preparation method of micro-nano warp architecture

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5457343A (en) * 1992-12-22 1995-10-10 Nec Corporation Carbon nanotubule enclosing a foreign material
US5919429A (en) * 1995-02-09 1999-07-06 Research Development Corporation Of Japan Ultrafine particle enclosing fullerene and production method thereof
US6038060A (en) * 1997-01-16 2000-03-14 Crowley; Robert Joseph Optical antenna array for harmonic generation, mixing and signal amplification
US6157043A (en) * 1996-12-20 2000-12-05 Nec Corporation Solenoid comprising a compound nanotube and magnetic generating apparatus using the compound nanotube
US6473351B2 (en) * 1999-02-12 2002-10-29 Board Of Trustees Operating Michigan State University Nanocapsules containing charged particles, their uses and methods of forming same

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB603888A (en) 1945-11-27 1948-06-24 Arthur Edward Williamson Apparatus for destroying weeds and vermin in the soil
US5933791A (en) * 1992-02-06 1999-08-03 Nec Corporation Cylindrical macromolecule and photometer and magnetometer using the same
DE69628425T2 (en) * 1995-03-31 2004-05-06 Hyperion Catalysis International, Inc., Cambridge CARBIDE NANOFIBRILLES AND METHOD FOR PRODUCING THE SAME

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5457343A (en) * 1992-12-22 1995-10-10 Nec Corporation Carbon nanotubule enclosing a foreign material
US5919429A (en) * 1995-02-09 1999-07-06 Research Development Corporation Of Japan Ultrafine particle enclosing fullerene and production method thereof
US6157043A (en) * 1996-12-20 2000-12-05 Nec Corporation Solenoid comprising a compound nanotube and magnetic generating apparatus using the compound nanotube
US6038060A (en) * 1997-01-16 2000-03-14 Crowley; Robert Joseph Optical antenna array for harmonic generation, mixing and signal amplification
US6473351B2 (en) * 1999-02-12 2002-10-29 Board Of Trustees Operating Michigan State University Nanocapsules containing charged particles, their uses and methods of forming same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9786848B2 (en) 2010-10-14 2017-10-10 University Of Utah Research Foundation Nanofiber-based heterojunction approach for high photoconductivity on organic materials

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