JP2004142958A - Three-component based nanotube consisting of boron-carbon-nitrogen atoms, and production method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a rectilinear three-component based nanotube consisting of boron-carbon-nitrogen atoms which has semiconductor characteristics and orientation properties. <P>SOLUTION: The carbon nanotube is produced by a chemical vapor deposition method. Boron oxide, gold oxide and nitrogen are reacted at 1,500 to 2,500 K. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The invention of this application relates to a ternary nanotube composed of boron-carbon-nitrogen atoms and a method for producing the same. More specifically, the invention of this application is useful as a semiconductor material, a flat panel display material, an emitter material, a heat-resistant filling material, a high-strength material, a catalyst, etc. The present invention relates to a ternary nanotube composed of boron-carbon-nitrogen atoms and a method for producing the same.
[0002]
[Prior art and its problems]
Nanometer-sized tubular carbon material in which carbon atoms are arranged in a hexagonal mesh and in a cylindrical shape is called a carbon nanotube, and although it has higher thermal conductivity than metal and is lighter, Since it has a strength close to that of diamond, it is expected to be applied to various fields.
[0003]
As a method for producing the carbon nanotubes, arc discharge and laser heating are known, but the carbon nanotubes produced by those methods do not show orientation (Science of Fulleren's and Carbon Nanotubes (Non-Patent Document 1)). Carbon Nanotubes and Related Structures (Non-Patent Document 2)). Therefore, there has been a demand for a method of producing carbon nanotubes exhibiting highly useful orientation. Recently, it has been found that oriented multi-walled carbon nanotubes can be synthesized by using a chemical vapor deposition method ( Large-Scale Synthesis of Aligned
Carbon Nanotubes (Non-Patent Document 3)).
[0004]
In recent years, multi-layer boron nitride nanotubes having a wider band gap than carbon nanotubes, that is, multi-layer boron nitride nanotubes having an insulating property, can be synthesized (CVD Growth of Boron Nitride Nanotubes (Non-Patent Document 4), JP-A-2000-109306). Japanese Patent Application Laid-Open No. 2002-97004 (Patent Document 2).
[0005]
On the other hand, it is known that a ternary nanotube composed of boron, carbon and nitrogen atoms is also synthesized by using a laser ablation method (Japanese Patent Application Laid-Open No. 7-187883 (Patent Document 3)). Nanotubes are used in semiconductor materials, flat panel display materials, emitter materials, heat-resistant filling materials, high-strength materials, catalysts, etc. as the above-mentioned carbon nanotubes, multi-walled boron nitride nanotubes, and other materials with properties not found in conventional materials. It is expected to be.
[0006]
However, in the conventional method of producing a ternary nanotube composed of boron, carbon, and nitrogen atoms by a laser ablation method, the shape of the produced ternary nanotube is curved or the smaller the number of layers of the nanotube, the more the electron becomes. Although it is practical with few phase defects affecting transport, conventional methods for producing three-component nanotubes can synthesize only nanotubes with a large number of layers. The performance of nanotubes could not be fully exhibited.
[0007]
[Non-patent document 1]
M. S. Dresselhaus et al. , (USA), Academic Press, San Diego, 1996 [Non-Patent Document 2].
P. J. F. Harris, (UK) "New Materials for the Twenty-first Century", Cambridge University Press, 1999 [Non-patent Document 3].
WZ Li et al. , "Science", (USA) 1996, Volume 274, p. 1701-1703
[Non-patent document 4]
Oleg R. Lourie et al. , "Chemistry of Materials", (USA), 2000, vol. 12, No. 7, p. 1808-1810
[Patent Document 1]
JP 2000-109306 A [Patent Document 2]
Japanese Patent Application Laid-Open No. 2002-97004 [Patent Document 3]
SUMMARY OF THE INVENTION Accordingly, the invention of this application has been made in view of the circumstances described above, has solved the problems of the prior art, has semiconductor characteristics, has a linear shape, and has good orientation. It is an object of the present invention to provide a method for producing a ternary nanotube composed of a boron-carbon-nitrogen atom having the following.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention of this application firstly comprises reacting carbon nanotubes, boron oxide, gold oxide, and nitrogen at a temperature of 1500 K to 2500 K. Provided is a method for producing a ternary nanotube composed of a nitrogen atom.
[0009]
Secondly, the invention of this application is the ternary nanotube comprising boron-carbon-nitrogen atoms according to the first invention, wherein carbon nanotubes produced by a chemical vapor deposition method are used as a raw material. And a method for producing the same.
[0010]
Thirdly, there is provided a method for producing a ternary nanotube composed of boron-carbon-nitrogen atoms, wherein a high-frequency induction heating furnace is used as a heating means in the first or second invention.
[0011]
Fourthly, in any one of the first to third inventions, there is provided a method for producing a ternary nanotube comprising boron-carbon-nitrogen atoms, which comprises separating a product from a reaction mixture under heating. provide.
Fifth, a ternary nanotube produced by the method for producing a ternary nanotube comprising a boron-carbon-nitrogen atom according to any one of the first to fourth inventions, which has semiconductor properties, Also provided is a ternary nanotube composed of boron-carbon-nitrogen atoms, which is linear and has orientation.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The method of the present invention for producing a ternary nanotube composed of boron-carbon-nitrogen atoms is characterized by reacting carbon nanotubes, boron oxide, gold oxide, and nitrogen at a temperature of 1500 K to 2500 K. As described above, by reacting carbon nanotubes, boron oxide, gold oxide, and nitrogen at a high temperature of 1500 K or more and 2500 K or less, several layers or less, more specifically, two to four layers or less, having semiconductor characteristics. Thus, a ternary nanotube composed of boron-carbon-nitrogen atoms having a long linear shape of about 1 to 2 μm and having orientation in one direction can be formed.
[0013]
In the invention of this application, the reaction of carbon nanotubes, boron oxide, gold oxide and nitrogen at a temperature of 1500 K or more and 2500 K or less causes deformation or evaporation of carbon nanotubes at a high temperature of 2500 K or more, and at a temperature of 1500 K or less. This is because the desired reaction does not proceed sufficiently, and the reaction speed is slow, so that a problem that a desired nanotube cannot be obtained in a short time occurs.
[0014]
In addition, gold oxide plays a role of a catalyst, and by mixing gold oxide, the generation rate of a ternary nanotube composed of boron-carbon-nitrogen atoms is extremely increased.
[0015]
In addition, by using a carbon nanotube produced by a chemical vapor deposition method as a raw material of the ternary nanotube, a carbon nanotube having an orientation can be used, and the carbon nanotube is composed of a boron-carbon-nitrogen atom having a higher orientation. It becomes possible to produce ternary nanotubes. At this time, a high-frequency induction heating furnace, which is a general-purpose device and suitable for heating the object to a high temperature, can be suitably used as the heating means.
[0016]
Furthermore, the method for producing a ternary nanotube composed of boron-carbon-nitrogen atoms according to the invention of the present application further comprises extracting a solid product from a liquid reaction mixture under heating, thereby further extracting the product. Can be dramatically increased.
[0017]
The ternary nanotube composed of boron-carbon-nitrogen atoms produced by the above-described production method is composed of 2 to 4 layers, has semiconductor properties, has a long linear shape, and has unidirectional orientation. Therefore, by utilizing these characteristics, it can be applied to materials in various fields such as semiconductor materials, flat panel display materials, emitter materials, heat-resistant filling materials, high-strength materials, and catalysts.
[0018]
Hereinafter, embodiments will be described with reference to the accompanying drawings, and embodiments of the present invention will be described in more detail. Of course, the present invention is not limited to the following examples, and it goes without saying that various aspects are possible in detail.
[0019]
【Example】
<Example 1>
By the method for producing a ternary nanotube of the invention of the present application, production of a ternary nanotube composed of boron-carbon-nitrogen atoms was attempted, and properties of the produced ternary nanotube were evaluated.
[0020]
First, carbon nanotubes having an orientation, boron oxide (B ₂ O ₃ ), and gold oxide (Au ₂ O ₃ ) produced by a chemical vapor deposition method were placed in a graphite crucible. The crucible was placed in a high-frequency induction heating furnace, and the temperature in the heating furnace was gradually increased to 1950 K while constantly flowing nitrogen gas at a flow rate of 3.2 liters per minute. After maintaining the temperature at this temperature for 30 minutes, it was cooled to room temperature again over 2 hours.
[0021]
At that time, the ternary nanotube, which is a solid product, and the liquid raw material were separated in a crucible under heating, and the product was taken out. By separating the product and the liquid raw material in this way, it is possible to dramatically increase the amount of the extracted product, and as a result, a ternary nanotube composed of about 50 mg of boron-carbon-nitrogen atoms It became possible to obtain.
[0022]
The ternary nanotube, which is a powdery product, is pulverized into fine particles, dispersed in carbon tetrachloride, subjected to ultrasonic waves, dropped onto a copper grid coated with a carbon film, and subjected to morphology with a high-resolution transmission electron microscope. Observations were made. The photograph of the result is shown in FIG.
[0023]
The photograph of FIG. 1A is a ternary nanotube composed of one boron-carbon-nitrogen atom, and it was confirmed from this photograph that a linear double-walled nanotube was formed. The photograph of FIG. 1 (b) shows a thin bundle of individual ternary nanotubes. From the figure, it can be seen that the ternary nanotube composed of boron-carbon-nitrogen atoms produced by the production method of the invention of this application is shown. It can be seen that the nanotubes are linear and have orientation. Further, FIG. 1C shows a state in which the three-component nanotubes are formed into a thick bundle, and it is understood that the bundled three-component nanotubes also have an orientation in one direction even in this state. .
[0024]
Next, electron energy loss spectrum analysis was performed. FIG. 2A is a measurement result of an electron energy loss spectrum of one four-walled ternary nanotube. Since the K absorption edges of boron, carbon, and nitrogen are 188, 284, and 401 eV, respectively, FIG. From (a), it was found that the composition ratio of boron, carbon, and nitrogen was about 0.55: 1.00: 0.60 in one four-walled ternary nanotube. FIG. 2B is a measurement result of an electron energy loss spectrum of a bundle of two-walled ternary nanotubes. The bundle of two-walled ternary nanotubes shows boron, carbon, and nitrogen from FIG. 2B. Was about 0.79: 0.48: 1.00.
[0025]
Next, charge transport characteristics were measured using a Fresnel projection microscope. FIG. 3 shows the measurement results. FIGS. 3A and 3B are Fresnel projection microscope images (photographs) of the ternary nanotubes before and after the measurement of the charge transport characteristics, respectively. FIG. 3C shows the results of the measurement of the charge transport characteristics. 6 is a graph showing a current-voltage characteristic curve obtained. The solid line, chain line and dotted line in FIG. 3 (c) are the results of the first, second and third measurements, respectively, and were obtained from their current-voltage characteristic curves with a band gap of about 1 eV. It can be seen that the ternary nanotube has semiconductor properties.
[0026]
As described above, by using the method for producing a ternary nanotube composed of boron-carbon-nitrogen atoms of the invention of the present application, a ternary system composed of boron-carbon-nitrogen atoms having a small number of layers of 2 to 4 is used. It is clear that nanotubes can be formed stably, and furthermore, these ternary nanotubes are linear and have unidirectional orientation and have semiconductor characteristics with a band gap of about 1 eV. Became.
[0027]
【The invention's effect】
As described in detail above, according to the manufacturing method of the invention of this application, semiconductor materials, flat panel display materials, emitter materials, heat-resistant filling materials, high-strength materials, useful as catalysts, etc. In addition, a ternary nanotube composed of boron-carbon-nitrogen atoms having orientation can be obtained. Further, since the ternary nanotubes produced by the production method of the present invention are nanotubes having several layers or less, they have excellent oxidation resistance and heat resistance, and are thus very useful in the above-mentioned application fields. It is expected to be a material.
[Brief description of the drawings]
FIG. 1 is a photograph of a high-resolution transmission electron microscope image of a ternary nanotube produced by a method for producing a ternary nanotube composed of boron-carbon-nitrogen atoms according to an embodiment of the present invention; One nanotube, (b) is a photograph of an aggregate of a thin bundle, and (c) is a photograph of an aggregate of a thick bundle.
FIG. 2 is a graph illustrating an electron energy loss spectrum of a ternary nanotube manufactured by a method for manufacturing a ternary nanotube composed of boron-carbon-nitrogen atoms according to an embodiment of the present invention. It is a measurement result of one four-walled nanotube, and (b) is a measurement result of a bundled double-walled nanotube.
FIGS. 3A and 3B are photographs before and after measurement of charge transport characteristics by a Fresnel projection microscope.
(C) A graph showing the measurement results of the current-voltage characteristics.

Claims (5)

A method for producing a ternary nanotube comprising boron-carbon-nitrogen atoms, wherein carbon nanotubes, boron oxide, gold oxide and nitrogen are reacted at a temperature of 1500 K to 2500 K. The method for producing a ternary nanotube comprising boron-carbon-nitrogen atoms according to claim 1, wherein a carbon nanotube produced by a chemical vapor deposition method is used as a raw material. The method for producing a ternary nanotube composed of boron-carbon-nitrogen atoms according to claim 1 or 2, wherein a high-frequency induction heating furnace is used as a heating means. The method for producing a ternary nanotube comprising boron-carbon-nitrogen atoms according to any one of claims 1 to 3, wherein a product is separated from the reaction mixture under heating. A ternary nanotube produced by the method for producing a ternary nanotube comprising a boron-carbon-nitrogen atom according to any one of claims 1 to 4, which has semiconductor properties, is linear, and A ternary nanotube composed of boron-carbon-nitrogen atoms, which has orientation.

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