JP2008221385A - Nanomaterial array base material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base material with oriented nanomaterials on its surface allowing narrowing of the intervals of the oriented nanomaterials to 10 nm or smaller. <P>SOLUTION: A monomolecular film of a diacetylene compound is formed on a surface of a sapphire substrate etc. The film is irradiated with an electron beam or a metal ion, and a linear region in which diacetylene compounds are polymerized and oriented is provided in the film. In the linear region, nanowire and nanotube are adsorbed and arrayed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a nanomaterial array substrate on which nanomaterials such as nanowires and nanotubes are arrayed on the surface.

  Application of nanomaterials such as nanowires and nanotubes to semiconductor devices, non-linear optical elements, and the like has been studied. For example, the operation of a field effect transistor using a nanotube has been reported (Non-Patent Document 1). The nanotube transistor uses a nanotube coated on a silicon substrate or a sapphire substrate. A single nanotube may be used as a channel, and a plurality of nanotubes may be used as a channel. When it is necessary to obtain a large drain current, it is advantageous to use a plurality of nanotubes as a channel. A silicon nanowire or the like is also used as a channel of a transistor. In this case, a plurality of nanowires may be used as a channel in the same manner as a nanotube (Non-patent Document 2). When a nanomaterial is used as a nonlinear optical material of a nonlinear optical element, the nanomaterial is used by coating the nanomaterial on a substrate transparent to the target light wavelength (Non-patent Document 3).

  As a method for applying the nanomaterial to the substrate, a method is known in which the nanomaterial is dispersed in a dispersion medium such as dichloroethane or dimethylformamide, and the dispersion is applied onto the substrate. Application methods include spin coating, dip coating, and spray coating. In this case, the nanomaterial is disposed on the substrate at random positions in a random direction (Non-Patent Document 4).

  When nanomaterials such as nanowires and nanotubes coated on the substrate surface are used for semiconductor devices and non-linear optical elements, it is expected that the characteristics will be improved if they are horizontally oriented on the substrate. For example, in a semiconductor device, it is expected that a larger drain current can be obtained when the nanomaterials are oriented with the same surface density than when the nanomaterials are oriented in a random manner.

  On the other hand, in a non-linear optical element, it is expected that polarization properties are imparted by arranging nanomaterials in one direction. In addition, when used for semiconductor devices and nonlinear optical elements, it is expected that the characteristics will be further improved if the density is increased as much as possible in addition to the orientation, in other words, if the interval between the aligned nanomaterials is made as small as possible.

However, the conventional technology cannot arrange nanomaterials at intervals of nanometer order.
F. Nihey et al., Jpn. J. Appl. Phys., 41, L1049 (2002) RS Friedman et al., Nature, 434, 1085 (2005) A. Maeda et al., Phys. Rev. Lett., 94, 47404 (2005) T. Fukao et al., Jpn. J. Appl. Phys., 45, 6524 (2006)

  An object of the present invention is to provide a substrate in which nanomaterials such as nanowires and nanotubes are aligned on the surface, and is characterized in that the interval between the aligned nanomaterials can be reduced to 10 nm or less. The purpose of this base material is to greatly improve the characteristics of high-performance semiconductor devices and non-linear optical elements.

  As a result of intensive investigations to solve the above problems, the present inventor formed a specific monomolecular film on a substrate, and when this monomolecular film was scanned with an electron beam, the molecules were polymerized and molecular chains were aligned. It was found that a polymer line was formed, and the molecular chain of this polymer adsorbed nanomaterials such as carbon nanotubes and ITO nanowires to form a line made of nanomaterials. The inventor further studied and finally completed the present invention.

  That is, the present invention comprises a substrate, a film formed on the substrate surface, a linear region oriented in the film, and a nanomaterial placed in contact with the linear region, and the film formed on the substrate surface Is a nanomaterial array base material comprising a diacetylene compound, and the linear region oriented in the film is composed of polydiacetylene.

  Note that the nanomaterial is preferably a nanotube or a nanowire.

  The nanotubes are preferably single-walled carbon nanotubes, multi-walled carbon nanotubes, or boron nitride nanotubes.

  The nanotubes preferably have a diameter of 10 nm or less and a length of 10 μm or less.

  The nanowire is preferably made of indium oxide, gallium nitride, silicon, indium oxide, cadmium oxide, indium nitride, tin oxide, iron oxide, or indium phosphide.

  The nanowire preferably has a diameter of 20 nm or less and a length of 2 μm or less.

  The substrate is preferably made of sapphire, quartz, silicon, gallium arsenide, indium phosphide, graphite, mica, calcium fluoride or magnesium oxide, and is preferably made of plastic.

  When the substrate is plastic, the plastics are vinyl chloride resin, polystyrene, ABS, polyethylene, polypropylene, polyamide resin, acrylic resin, fluorine resin, polycarbonate, methylpentene resin, polyurethane, phenol resin, melamine resin, epoxy resin, polyethylene. Naphthalate or polyethylene sulfonate is preferred.

  The film formed on the substrate surface is preferably a monomolecular film, and it is also preferable that a plurality of monomolecular films are laminated.

  According to the present invention, nanomaterials such as nanowires and nanotubes can be formed on a substrate at very small intervals, and it is possible to improve the characteristics of semiconductor devices and nonlinear optical elements. This method is effective for various substrates, and can be selected according to purposes such as insulation and transparency.

  The nanomaterial array substrate of the present invention will be described with reference to the drawings.

  1A is a perspective view of the nanomaterial array substrate of the present invention, and FIG. 1B is a cross-sectional view taken along line AA ′ of FIG.

  In the figure, a film 2 is provided on a substrate 1, and a plurality of linear regions 3 are provided on the film 2. The line width of the linear region 3 can be 10 nm or less, and the interval is usually 10 nm to 1,000 nm, but can also be 10 nm or less. Note that the line width and spacing are appropriately determined by the nanomaterial 4 formed in contact therewith. Furthermore, there is a nanomaterial 4 made of nanotubes or nanowires in contact with the linear region 3.

  In the present invention, the substrate 1 can be appropriately selected from inorganic and organic materials, but is not violated by the solvent used for disposing the nanomaterial after the formation of the film 2 or the linear region 3. Is desirable. As the inorganic material, for example, sapphire, quartz, silicon, gallium arsenide, indium phosphide, graphite, mica, calcium fluoride, magnesium oxide and the like are used. For organic materials, plastics are useful, especially vinyl chloride resin, polystyrene, ABS, polyethylene, polypropylene, polyamide resin, acrylic resin, fluorine resin, polycarbonate, methylpentene resin, polyurethane, phenol resin, melamine resin, epoxy Resins, polyethylene naphthalate, polyethylene sulfonate and the like can be exemplified as preferable examples.

  The film 2 provided on the substrate 1 is preferably a monomolecular film of a compound that is easily polymerized by electrons or the like. In particular, a monomolecular film of a diacetylene compound is obtained by applying a voltage pulse with a probe of a scanning probe microscope. A polymerization reaction occurs in a chain from the application position, and a molecular chain composed of polydiacetylene is formed linearly (Japanese Patent Laid-Open No. 2002-69111).

  In the diacetylene compound, the molecular chain direction is parallel to a specific direction of the monomolecular film. By utilizing this property, the distance between molecular chains can be controlled to 10 nm or less by appropriately controlling the pulse application position. On the other hand, the molecular chain formed in this way has a property that nanomaterials such as nanowires and nanotubes are very easily adsorbed.

  Therefore, when the nanomaterial is dispersed on the monomolecular film, the nanomaterial is also oriented and formed in a very good yield according to the orientation direction of the molecular chain. By narrowing the distance between the molecular chains serving as templates, the distance between the oriented nanomaterials can also be set to 10 nm or less.

  As the diacetylene compound here, for example, 10,12-pentacosadiynoic acid, 10,12-nonacosadiynoic acid and the like are preferable because they are readily available and easy to handle.

  As nanomaterials, various types of nanotubes and nanowires have been developed at present, and these can be appropriately selected and used. For example, as the nanotube, a carbon nanotube, a boron nitride nanotube, or the like can be raised, and either a single layer or a multilayer may be used. Examples of the nanowire include materials made of indium oxide, gallium nitride, silicon, indium oxide, cadmium oxide, indium nitride, tin oxide, iron oxide, indium phosphide, and the like.

  A compound for film formation is dissolved on a substrate 1 in a suitable solvent, and a monomolecular film is formed on the surface of a medium such as water by spin coating, dip coating, or the like (Langmuir-Broget method). Then, a compound film 2, preferably a monomolecular film, is formed. If necessary, a plurality of monomolecular films can be laminated by repeating this coating step several times. It is preferable to laminate a plurality of layers in view of strength, orientation, and the like. Next, a voltage pulse is applied to the film 2 with a probe of a scanning probe microscope, and the compound used for film formation is polymerized to form a linear region 3. A nanomaterial is disposed on the linear region 3 of the substrate on which the linear region 3 is formed. For this arrangement, the nanomaterial is dispersed in an appropriate solvent, and after application or immersion, excess nanomaterial is washed away.

  What is important in these scans is the molecular chain orientation of the material constituting the linear region 3 formed in the film 2 formed on the substrate 1 and the interaction between the nanomaterial and the molecular chain. . The orientation of the molecular chain is greatly influenced by the state of the self-organized arrangement of the elementary compound film (monomolecular film). Therefore, the nature of the underlying substrate and the form of the monomolecular film are considered to be important factors. As described above, as described above, a substrate made of sapphire, quartz, silicon, gallium arsenide, indium phosphide, graphite, mica, calcium fluoride, magnesium oxide, or the like is preferable. In this way, the underlying substrate has a relatively high degree of freedom. As for the form of the film formed on the substrate, a film in which a plurality of monomolecular films are laminated is preferable because the orientation is improved.

  The mechanism of the interaction between the nanomaterial and the molecular chain formed as a linear region is currently unknown, but it is assumed that the possible mechanism is physical adsorption with charge transfer.

  Nanowires include nanowires such as indium oxide, gallium nitride, silicon, indium oxide, cadmium oxide, indium nitride, tin oxide, iron oxide, and indium phosphide, and nanotubes include carbon nanotubes and boron nitride nanotubes. Good results have been obtained. Therefore, it appears that the interaction is strong regardless of the nature of the material.

  As a solvent used when forming on the substrate, for example, chloroform can be used. Moreover, as a solvent used when arrange | positioning nanomaterial in a linear area | region, a dichloroethane and a dimethylformamide are suitable, for example.

  Hereinafter, the present invention will be described by way of examples.

Example 1
A schematic diagram of this example is shown in FIG. Hereinafter, description will be made with reference to this figure.

  A diacetylene compound film 21 was formed as a monomolecular layer on a sapphire substrate 11 having a C-plane as a surface. Next, a voltage pulse was applied with a probe of a scanning probe microscope, and a linear region 31 made of polydiacetylene was arranged in the film 21 of the diacetylene compound. Then, the single-walled carbon nanotube 41 was arrange | positioned on the linear area | region 31 which consists of polydiacetylene, and the nanomaterial arrangement | sequence base material was obtained.

  The diacetylene compound film 21 formed on the surface of the sapphire substrate 11 uses 10,12-pentacosadiynoic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) as the diacetylene compound, which is dissolved in benzene to form a dilute solution. The sapphire substrate was immersed in the solution and then pulled up at a low speed. This procedure was repeated to laminate three monolayers.

  The voltage pulse applied to the probe of the scanning probe microscope was set to 10 volts. By this treatment, polymerization occurred in a chain from the pulse application point, and a linear region 31 made of polydiacetylene was formed. The line width was about 1 nm. The linear region 31 could be formed periodically by repeating the pulse application at different locations. The interval between the linear regions 31 made of polydiacetylene could be 10 nm by setting the pulse application interval to 10 nm.

  Single-walled carbon nanotubes were coated on the substrate thus formed. The single-walled carbon nanotubes were synthesized by laser evaporation using nickel and cobalt as a catalyst and graphite powder as a raw material. The single-walled carbon nanotubes had an average diameter of 1 nm and an average length of 1 μm. For this coating, the synthesized single-walled carbon nanotubes were dispersed in dichloroethane, subjected to ultrasonic treatment, and filtered through a membrane filter. After coating, the substrate surface was sufficiently washed with ethanol, and the tube of excess single-walled carbon was washed away.

  When the obtained nanomaterial array substrate was observed with a scanning electron microscope and a scanning probe microscope, it was confirmed that the single-walled carbon nanotubes 51 were adsorbed and disposed on the linear regions 31 made of a polyacetylene compound. In addition, 90% of the linear region was covered with the single-walled carbon nanotube.

  Similar results were obtained even when single-walled carbon nanotubes were synthesized by other methods. Similar results were obtained with multi-walled carbon nanotubes and boron nitride nanotubes. In addition, it is desirable that the diameter of the nanotube is 10 nm or less, and the best result was obtained when the diameter was 2 nm or less. The length is preferably 10 μm or less, and the best result is 1 μm or less.

Example 2
A schematic diagram of this example is shown in FIG. Hereinafter, description will be made with reference to this figure.

  A monomolecular layer film 22 of a diacetylene compound was formed on the silicon substrate 12 having the (111) plane from which the oxide film on the surface was removed. Next, by irradiating the surface with gallium ions in a pulse shape, the diacetylene compound is linearly polymerized from the irradiation position of the gallium ions, and the linear region 32 made of polydiacetylene is formed in the film 22 made of the diacetylene compound. Arranged. Thereafter, silicon nanowires 42 were disposed on the linear regions 32 made of a polyacetylene compound to obtain a nanomaterial array substrate.

  The monomolecular film 22 of the diacetylene compound formed on the surface of the silicon substrate 11 uses 10,12-nonacosadiynoic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) as the diacetylene compound, which is dissolved in toluene and diluted. The silicon substrate was immersed in the solution and then pulled up at a low speed. This procedure was repeated to laminate five monomolecular layers.

The line width of the linear region 42 made of polydiacetylene formed by irradiating the film of the diacetylene compound developed on the surface of the silicon substrate with gallium ions was about 1 nm. Further, when the irradiation amount of gallium ions was 10 ¹² per cm ² , the interval between the linear regions 42 made of the polyacetylene compound was about 10 nm. In addition, by adjusting the irradiation amount of gallium ions, the interval between the linear regions 42 can be adjusted, and the distance can be made smaller than 10 nm. Further, the irradiated ions were gold, beryllium, and silicon, and all of them had similar results.

  Silicon nanowires were applied on the substrate thus formed. Silicon nanowires are synthesized by chemical vapor deposition using gold as a catalyst and monosilane gas as a raw material. The silicon nanowire had a diameter of 10 nm and a length of 1 μm. The synthesized silicon nanowires were dispersed in benzene, subjected to ultrasonic treatment, and then filtered through a membrane filter. This dispersion was applied onto a silicon substrate, and then thoroughly washed with methanol.

  When the obtained nanomaterial array substrate was observed with a scanning electron microscope and a scanning probe microscope, it was confirmed that the silicon nanowires 42 were disposed in the linear region 32 made of a polyacetylene compound.

  The same experiment was performed using nanowires made from other materials such as indium oxide, gallium nitride, silicon, indium oxide, cadmium oxide, indium nitride, tin oxide, iron oxide, indium phosphide, and similar results. there were.

  Further, a plastic substrate was used in place of the silicon substrate, but the same result as in the case of the silicon substrate was obtained. As plastic substrates, vinyl chloride resin, polystyrene, ABS, polyethylene, polypropylene, nylon, acrylic resin, fluorine resin, polycarbonate, methylpentene resin, polyurethane, phenol resin, melamine resin, epoxy resin, polyethylene naphthalate, polyethylene sulfonate The thing which consists of etc. was used. As a dispersion medium for silicon nanowires, water and alcohol were appropriately used according to the resin material so as not to violate the plastic.

  The nanowire desirably has a diameter of 20 nm or less, and good results were obtained at 5 nm or less. Further, the length is desirably 2 μm or less.

  The nanomaterial array substrate of the present invention can be used as a channel material of a semiconductor device or as a nonlinear optical part of a nonlinear optical element, and contributes to improving the characteristics of each applied component.

It is the perspective view (A) and sectional drawing (B) of the nanomaterial arrangement | sequence base material of this invention. 1 is a perspective view of a nanomaterial array substrate produced in Example 1. FIG. 3 is a perspective view of a nanomaterial array substrate produced in Example 2. FIG.

Explanation of symbols

1 Substrate 2 Film (Monomolecular film)
3 Linear region 4 Nanomaterial 11 Sapphire substrate 12 Silicon substrate 21, 22 Film 31 and 32 made of diacetylene compound Linear region 41 made of polydiacetylene 41 Single-walled carbon nanotube 42 Silicon nanowire

Claims (14)

  A substrate, a film formed on the substrate surface, a linear region oriented in the film, and a nanomaterial placed in contact with the linear region, and the film formed on the substrate surface is made of a diacetylene compound A nanomaterial array substrate in which linear regions oriented in the film are made of polydiacetylene.   The nanomaterial array substrate according to claim 1, wherein the nanomaterial is a nanotube.   The nanomaterial array substrate according to claim 2, wherein the nanotube is a single-walled carbon nanotube, a multi-walled carbon nanotube, or a boron nitride nanotube.   5. The nanomaterial array substrate according to claim 4, wherein the diameter of the nanotube is 10 nm or less.   5. The nanomaterial array substrate according to claim 4, wherein the length of the nanotube is 10 μm or less.   The nanomaterial array substrate according to claim 1, wherein the nanomaterial is a nanowire.   The nanomaterial array substrate according to claim 6, wherein the nanowire is made of indium oxide, gallium nitride, silicon, indium oxide, cadmium oxide, indium nitride, tin oxide, iron oxide, or indium phosphide.   The nanomaterial array substrate according to claim 6, wherein the diameter of the nanowire is 20 nm or less.   The nanomaterial array substrate according to claim 6, wherein the length of the nanowire is 2 µm or less.   2. The nanomaterial array substrate according to claim 1, wherein the substrate is made of sapphire, quartz, silicon, gallium arsenide, indium phosphide, graphite, mica, calcium fluoride, or magnesium oxide.   The nanomaterial array substrate according to claim 1, wherein the substrate is made of plastic.   The plastic is vinyl chloride resin, polystyrene, ABS, polyethylene, polypropylene, polyamide resin, acrylic resin, fluorine resin, polycarbonate, methyl pentene resin, polyurethane, phenol resin, melamine resin, epoxy resin, polyethylene naphthalate or polyethylene sulfonate. The nanomaterial arrangement | sequence base material of Claim 11 characterized by these.   The nanomaterial array substrate according to claim 1, wherein the film formed on the substrate surface is a monomolecular film.   The nanomaterial array substrate according to claim 1, wherein the film formed on the substrate surface is a laminate of a plurality of monomolecular films.

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