JP2005059135A - Device using carbon nano-tube, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device using a carbon nano-tube that has high directivity, diameter of about 1-20 nm, and has a density of 1×10<SP>11</SP>/cm<SP>2</SP>or more. <P>SOLUTION: The carbon nano-tubes constituting the device using the carbon nano-tubes are formed in a porous body having cylindrical pores, separated from each other by the porous body, and formed substantially vertically to the substrate in the pores. The diameters of the carbon nano-tubes are 1 nm or longer and shorter than 20 nm, and the formation density thereof is 1.5×10<SP>11</SP>/cm<SP>2</SP>or more. The porous body 14 is formed by removing columnar materials mainly containing aluminum from a structure where the columnar materials are dispersed in a member made of germanium capable of forming eutectic crystal, silicon, or composite of germanium and silicon. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a device using a carbon nanotube and a manufacturing method thereof. Specifically, the present invention relates to a device using carbon nanotubes as a functional device such as a quantum effect device, an electronic device, a micromachine device, and a chemical sensor, and a manufacturing method thereof.

  A carbon nanotube is a fullerene having a cylindrical structure in which several or one layer of graphite is wound, and is a new carbon material discovered in 1991.

  Carbon nanotubes are thermally and chemically stable and have a mechanical strength that is about three orders of magnitude higher than commercially available carbon fibers. Furthermore, since the nanotube has a feature that it becomes a metal or a semiconductor due to a difference in structure, it can be expected to be applied to an electronic device or the like by combining, for example, a concentric cylindrical metal tube and a semiconductor tube.

  Also, when applying carbon nanotubes to functional devices such as electron-emitting devices, chemical sensors, and infrared image sensors, carbon nanotubes with high directivity, small diameter, and uniform diameter may be formed at high density. It becomes an important technology. Therefore, in order to solve this technical problem, many methods for forming carbon nanotubes using anodized aluminum (anodized alumina) as a template have been reported.

  Here, the anodization of aluminum will be briefly described. In the anodic oxidation of aluminum, when an aluminum film formed on an aluminum plate or substrate is anodized in an acidic electrolyte, a porous oxide film (anodized alumina) is formed. (Refer nonpatent literature 1). The feature of this porous oxide film is the uniqueness that extremely fine cylindrical pores (nanoholes) with a diameter of several nanometers to several hundred nanometers are arranged in parallel at intervals (cell size) of several tens of nanometers to several hundred nanometers. It has a typical geometric structure. These cylindrical pores have a high aspect ratio and relatively excellent cross-sectional diameter uniformity when the pore spacing is several tens of nanometers or more. The diameter and interval of the pores can be controlled to some extent by adjusting the type of acid and voltage during anodization. Further, the thickness of the anodized film and the depth of the pores can be controlled to some extent by controlling the anodizing time.

Next, an example in which carbon nanotubes are formed using anodized alumina as a template will be briefly described (see Non-Patent Document 2). By forming carbon nanotubes using anodized alumina as a template, carbon nanotubes can be formed perpendicular to the substrate, and the diameter of the carbon nanotubes can be controlled in the range of 10 to 350 nm, and the carbon nanotube density can be increased. It is shown that it can be formed at about 10 ¹¹ cm ⁻² .

  In addition, an example is shown in which a carbon nanotube produced using anodized alumina as a template is used as an electron-emitting device (see Non-Patent Document 3). According to this document, it is shown that an electron-emitting device using carbon nanotubes having a thin diameter of 10 nm can emit electrons with a very low electric field.

As described above, it has been reported many times that carbon nanotubes having high directivity and a diameter of about 10 nm can be formed at high density by forming carbon nanotubes using anodized alumina as a template.
RC.Furneaux, WRRigby & A.P.Davidson Nature Vol.337 (1989) p.147 APPLIED PHYSICS LETTERS VOLUME 75, NUMBER 3 (1999), p.367〜369 Materials Science and Engineering C 23 (2003) p.141〜146

However, in anodized alumina conventionally used as a template for carbon nanotubes, the practically usable pore diameter is 10 nm or more, and the pore density is about 10 ¹¹ cm ⁻² . In devices that require smaller diameter carbon nanotubes or devices that require higher density carbon nanotubes, there have been technical limitations. Moreover, since anodized alumina used as a template is an insulator material, it has been difficult to inject charges from the template into carbon nanotubes.

The present invention has been made in view of the above, and a carbon nanotube having high directivity and having a diameter of about 1 to 20 nm formed at a density of 1 × 10 ¹¹ pieces / cm ² or more. The device used is provided. Moreover, the device using the carbon nanotube which can inject an electric charge from a casting_mold | template is provided.

  Furthermore, this invention provides the method which can manufacture the device using the above-mentioned carbon nanotube simply.

  In order to solve the above-mentioned problems, a first invention of the present application is a device having carbon nanotubes held in a pore of a porous body having columnar pores, wherein the porous body is a first body The columnar substance including the component is removed from the structure dispersed in the member including the second component capable of forming a eutectic with the first component. It is formed. Moreover, it is desirable that the porous body is a thin film.

  As described above, the columnar substance including the first component is dispersed from the structure including the second component capable of forming a eutectic with the first component. By using a porous body formed by removing carbon, carbon nanotubes having a density and diameter that cannot be achieved by an aluminum anodic oxide film can be formed.

  In the device using the carbon nanotube according to the present invention, the first component is aluminum, the second component is a semiconductor material, and the ratio of the semiconductor material in the structure is 20 atomic% or more. It is characterized by being in the range of 70 atomic% or less.

  In the device using the carbon nanotube according to the present invention, it is preferable that the semiconductor material is any one of silicon, germanium, and a composite of silicon and germanium.

  Further, the device using the carbon nanotube according to the present invention is characterized in that the main component element of the porous body having the columnar pores is any one of silicon, germanium, silicon and germanium except for oxygen. To do.

  Thus, when the material constituting the porous body is a semiconductor material such as silicon, germanium, or a composite of silicon and germanium, charges can be injected into the carbon nanotubes from the porous body.

  Furthermore, it is desirable that the average diameter of the columnar holes is 1 nanometer or more and less than 20 nanometers. By setting it as such a pore diameter, the single wall carbon nanotube with a small diameter and the multi wall carbon nanotube with a comparatively large diameter can be made separately.

Furthermore, the average density of the columnar holes is preferably 1.5 × 10 ¹¹ holes / cm ² or more. By setting such an average density, a carbon nanotube device having carbon nanotubes formed at a higher density than a carbon nanotube device having carbon nanotubes formed using anodized alumina as a template can be formed.

  The first component is preferably a crystalline material, and the second component is preferably an amorphous material.

  Further, the second invention of the present application is such that a columnar material including the first component is dispersed in a member including the second component capable of forming a eutectic with the first component. A step of preparing the structure, a removal step of removing the columnar substance, a step of introducing a catalyst material into the pores of the porous body having columnar pores obtained by the removal step, and the catalyst And a step of introducing a carbon nanotube into the pores of the porous body into which the material has been introduced.

  According to a third invention of the present application, a columnar substance including the first component is dispersed in a member including the second component capable of forming a eutectic with the first component. Prepared by the step of preparing the structure, the removal step of removing the columnar substance, the crystallization step of crystallizing the porous body having the columnar pores obtained by the removal step, and the crystallization step. A carbon nanotube, comprising: a step of introducing a catalyst material into the pores of the porous body, and a step of introducing a carbon nanotube into the pores of the porous body into which the catalyst material has been introduced. Device manufacturing method.

  According to a fourth invention of the present application, a columnar substance including the first component is dispersed in a member including the second component capable of forming a eutectic with the first component. A step of preparing the structure, a removal step of removing the columnar substance, a step of oxidizing the porous body having columnar pores obtained by the removal step, and an oxide porous material produced by the oxidation step A device using carbon nanotubes, comprising a step of introducing a catalyst material into the pores of a body, and an introduction step of introducing carbon nanotubes into the pores of a porous body into which the catalyst material has been introduced It is a manufacturing method.

  In the device manufacturing method using the carbon nanotubes of the second to fourth inventions of the present application, the first component is aluminum, and the second component is silicon, germanium, a composite of silicon and germanium. Any semiconductor material is desirable.

  By these production methods, carbon nanotubes can be formed in a porous body having a small pore diameter, a high pore density, and having an insulating property or a porous material having a semiconductor property.

  Explaining the circumstances that led to the present invention, the present inventors have been researching on a microstructure using aluminum, and as a result, the following knowledge has been reached.

  That is, when an aluminum film is formed on a substrate by a film forming method for forming a material in a non-parallel state such as a sputtering method, silicon and germanium are added. Has been found to be formed in silicon, germanium, or a composite of silicon and germanium. In addition, by immersing the columnar-structured aluminum film in a solution that preferentially dissolves aluminum over silicon or germanium or a composite of silicon and germanium, pore diameters and pores that cannot be formed by aluminum anodization It was found that a porous body having a density can be formed.

  Furthermore, it was found that the material constituting the porous body can be changed to an oxide by oxidizing the formed porous body.

  Furthermore, it has been found that by crystallization of the formed porous body in a reducing atmosphere, semiconductor characteristics can be imparted to the material constituting the porous body.

  Therefore, the present inventors have advanced earnestly research based on the above findings, and have come to achieve the present invention.

  Note that an aluminum silicon film or an aluminum germanium film in which the amount of silicon or germanium or a composite of silicon and germanium is 20 to 70 atomic% with respect to the total amount of aluminum and silicon, aluminum and germanium, or aluminum, silicon, and germanium, or The reason for forming the aluminum silicon germanium film is that aluminum forms a nanostructure having a columnar shape only in this range. That is, when the amount of silicon (and / or germanium) is less than 20 atomic% with respect to the total amount of aluminum and silicon (and / or germanium), the diameter of the structure containing aluminum, that is, the size is 15 nm or more, It does not form a columnar structure including it. On the other hand, when the amount of silicon (and / or germanium) exceeds 70 atomic% with respect to the total amount of aluminum and silicon (and / or germanium), a columnar structure containing aluminum cannot be confirmed by a normal electron microscope. .

In addition, a catalyst for carbon nanotubes is formed on a porous body made of silicon (or silicon oxide), germanium (or germanium oxide), a composite of silicon and germanium (or an oxide thereof) by an electrodeposition method or the like. The material is introduced, and then carbon nanotubes are formed from the catalyst material, so that the carbon nanotubes having a very small diameter (for example, 1 nm to less than 20 nm) are densely formed (for example, 1 × 10 ¹¹ pieces / cm ^2). Above). After forming the carbon nanotubes, it is also possible to remove silicon (or silicon oxide), germanium (or germanium oxide), and a composite of silicon and germanium (or their oxides), which are porous members. It is.

According to the present invention, from the structure in which the columnar substance including the first component is dispersed in the member including the second component capable of forming a eutectic with the first component, A porous material formed by removing columnar substances is filled with a catalyst material for growing carbon nanotubes, and then carbon nanotubes are grown from the catalyst material, so that the diameter is 1 nanometer or more and 20 nanometers. It is possible to provide a device using carbon nanotubes in which carbon nanotubes that are less than 1 are formed at a high density (1 × 10 ¹¹ pieces / cm ² or more).

  In addition, the present invention can provide a production method capable of easily producing a device using the carbon nanotube.

  Next, the best mode of the present invention will be described with reference to the drawings.

<Configuration of devices using carbon nanotubes>
FIG. 1 is a schematic view showing an example of a device using the carbon nanotube of the present invention. This example shows an example of a device using carbon nanotubes in which carbon nanotubes having a diameter of several to several tens of nanometers are formed in pores on a substrate. In FIG. 1, 11 is a device using carbon nanotubes, 12 is a carbon nanotube, 13 is a substrate, 14 is a porous body, 15 is a catalyst material, and 16 is an underlayer.

  The device using the carbon nanotube of the present invention is characterized in that the carbon nanotube constituting the device using the carbon nanotube is formed in a porous body having cylindrical pores. The carbon nanotubes are separated from each other by a porous body as shown in FIG. 1, and are formed substantially perpendicular to the substrate in the pores.

Further, the diameter of the carbon nanotube constituting the device using the carbon nanotube of the present invention (indicating the average diameter of the carbon nanotube viewed from the film surface) is 1 nanometer or more and less than 20 nanometer. Furthermore, the formation density of carbon nanotubes (showing the average density of carbon nanotubes as viewed from the film surface) is 1.5 × 10 ¹¹ pieces / cm ² or more.

  Furthermore, in the porous body 14 of the present invention, the columnar substance including the first component is dispersed in the member including the second component capable of forming a eutectic with the first component. It is formed by removing columnar substances from the structure. Here, the columnar substance including the first component is composed of, for example, a material mainly composed of aluminum. The member including the second component capable of forming a eutectic with the first component is made of, for example, germanium, silicon, or a composite of germanium and silicon.

  Furthermore, the porous member constituting the device using the carbon nanotube of the present invention is made of a semiconductor material such as silicon, germanium, a composite of silicon and germanium, or an oxide of these semiconductor materials (except for oxygen). Insulator material).

  Further, the porous member constituting the device using the carbon nanotube of the present invention may be mainly composed of silicon, germanium, a composite of silicon and germanium, or an oxide thereof except oxygen. Although desirable, it may contain various elements such as aluminum (Al), oxygen (O), argon (Ar), nitrogen (N), and hydrogen (H) of several to several tens atomic%.

  Further, in FIG. 1, there is no problem even if the porous body is removed.

  Furthermore, the substrate used in the device using the carbon nanotube of the present invention is not particularly limited, and various types of substrates such as a semiconductor substrate such as a silicon substrate, a glass substrate such as quartz may be used. it can.

Furthermore, the catalyst material used in the device using the carbon nanotube of the present invention is not particularly limited, and any material that does not easily form a compound with carbon may be used. For example, Ni, Co, Fe, Fe ₂ O ₃ etc. can be used. In particular, a material having a eutectic composition with carbon is preferable.

  Furthermore, the underlayer material used in the device using the carbon nanotube of the present invention is not particularly limited, and may be an electrically conductive material, for example, W, Cu, Pt, Au, etc. are used. it can.

  In addition, the carbon nanotube used in the device using the carbon nanotube of the present invention may be a single carbon nanotube or a multi-wall carbon nanotube.

<Device manufacturing method using carbon nanotubes>
Hereinafter, a device manufacturing method using the carbon nanotubes according to the present invention will be described in detail. 2 and 3 are process diagrams showing an embodiment of a device manufacturing method using the carbon nanotube of the present invention. 2 and 3, the device manufacturing method using the carbon nanotube of the present invention is characterized by having the following steps (a) to (e).

  (A) Process: The process of forming the metal which is a base layer on a board | substrate. For example, the base layer 22 such as Pt or W is formed on the single crystal silicon as the substrate 21 by sputtering or vacuum deposition.

  (B) Step: A structure in which a columnar substance including a first component is dispersed in a member including a second component capable of forming a eutectic with the first component is an underlayer Steps to prepare above. For example, as shown in FIG. 6A, aluminum and silicon (or germanium or a composite of silicon and germanium) forming a columnar structure (first component) 43 in a matrix (second component) 42 are prepared. A structure 44 (an aluminum silicon mixed film, an aluminum germanium mixed film, or an aluminum silicon germanium composite film) is formed on the substrate 41 by a method capable of forming a non-equilibrium material such as sputtering.

When an aluminum silicon mixed film, an aluminum germanium mixed film, or an aluminum silicon germanium mixed film is formed by such a method, aluminum and silicon (or germanium or a composite of silicon and germanium) become a metastable eutectic structure, and aluminum Forms a nanostructure (columnar structure) of several nanometers in a silicon (or germanium or silicon-germanium composite) matrix and separates in a self-organized manner. The aluminum at that time has a substantially cylindrical shape, the pore diameter is 1 nanometer or more and less than 20 nanometer, and the average density is 1.5 × 10 ¹¹ pieces / cm ² or more.

  In the mixed film of aluminum and silicon (or germanium or a composite of silicon and germanium), the amount of silicon (or germanium or a composite of silicon and germanium) in the formed film is aluminum and silicon (or germanium). It is 20-70 atomic% with respect to the whole quantity of, Preferably it is 25-65 atomic%, More preferably, it is 30-60 atomic%. If the amount of silicon is within such a range, an aluminum silicon mixed film (or an aluminum germanium mixed film or an aluminum silicon germanium mixture) in which columnar structures of aluminum are dispersed in a silicon (or germanium or silicon-germanium composite) region. Is obtained.

  The atomic% indicating the ratio of aluminum and silicon (or germanium or a composite of silicon and germanium) refers to the ratio of the number of atoms of silicon (or germanium or a composite of silicon and germanium) and aluminum, and atom% Alternatively, it is also described as at%. For example, silicon (or germanium or a composite of silicon and germanium) in an aluminum silicon mixed film (or aluminum germanium mixed film or aluminum silicon germanium mixture) by inductively coupled plasma emission spectrometry (ICP method). It is the value when the amount of aluminum is quantitatively analyzed.

(C) Step: Next, a step of removing the columnar substance. For example, as shown in FIG. 6B, the columnar substance aluminum in the aluminum silicon mixed film (or aluminum germanium mixed film or aluminum silicon germanium mixture) is etched with phosphoric acid to form a matrix (here, silicon or germanium). Alternatively, pores are formed in a composite of silicon and germanium or an oxide thereof. Thereby, the porous body 46 is formed. The pores 45 in the porous body have an average density of 1.5 × 10 ¹¹ holes / cm ² or more and an average pore diameter of 1 nanometer or more and less than 20 nm.

  Examples of the solution used for etching include acids such as phosphoric acid, sulfuric acid, hydrochloric acid, and chromic acid solution that dissolve aluminum and hardly dissolve silicon (or germanium). Alternatively, an alkali such as sodium hydroxide can be used if there is no problem in the formation of pores by etching, and it is not particularly limited to the type of acid or the type of alkali. Also, a mixture of several types of acid solutions or several types of alkali solutions may be used. Etching conditions such as solution temperature, concentration, time, etc. can be appropriately set according to the porous body to be produced.

  Step (d): Next, an introduction step of introducing the catalyst material into the pores of the porous body having columnar pores obtained by the removal step. For example, the porous material 25 is filled with a catalyst material 26 such as Co using an electrodeposition method or the like. Here, the catalyst material 26 to be filled is typically Co, Ni, Fe, or the like which hardly forms a compound with the carbon material, but is not limited to this, and is already a catalyst material for forming carbon nanotubes. It is possible to use various materials used.

  (E) Step: Next, an introduction step of introducing carbon nanotubes into the pores of the porous body into which the catalyst removal metal has been introduced. For example, the carbon nanotubes 27 are formed using a thermal decomposition method. Ethylene or propane as a raw material gas is introduced into the reaction vessel together with hydrogen, and the porous body in the reaction vessel is set to a temperature range of 550 to 850 ° C., and carbon is only on the catalyst material in the pores of the porous body Nanotubes are formed. In addition to this, the source gas includes saturated hydrocarbons such as methane, ethane, propane, butane, hexane, and cyclohexane, unsaturated hydrocarbons such as ethylene, propylene, benzene, and toluene, oxygen such as acetone, methanol, and carbon monoxide. Ingredients containing can be used.

  Through such steps, the device 28 using carbon nanotubes is formed.

  Next, FIGS. 4 and 5 are process diagrams showing another embodiment of a device manufacturing method using the carbon nanotube of the present invention. The detailed description is substantially the same as that shown in FIGS.

  (A ') Process: The process of forming the metal which is a base layer on a board | substrate.

  Step (b ′): A structure in which a columnar substance including the first component is dispersed in a member including the second component capable of forming a eutectic with the first component is formed below. The process of preparing on the formation.

  (C ′) Step: Next, a step of removing the columnar substance.

  (D ′) Step: A crystallization step of crystallizing a porous body having columnar pores obtained by the removal step by thermal annealing or the like. For example, thermal annealing is performed in a reducing atmosphere such as hydrogen. Note that the crystallization method is not limited to thermal annealing, and crystallization using a laser is also possible. By this step, the porous body 36 in which the constituent members are crystallized is formed.

  Step (e ′): Next, an introduction step of introducing the catalyst material into the pores of the porous body having columnar pores obtained by the crystallization step.

  Step (f ′): Next, an introduction step of introducing carbon nanotubes into the pores of the porous body into which the catalyst metal has been introduced.

  Through these steps, a device using carbon nanotubes is formed.

  Next, FIGS. 7 and 8 are process diagrams showing another embodiment of a device manufacturing method using the carbon nanotube of the present invention. The detailed description is substantially the same as that shown in FIGS.

  (A ″) Step: A step of forming a metal as an underlayer on the substrate.

  (B ″) Step: A structure in which a columnar substance including a first component is dispersed in a member including a second component capable of forming a eutectic with the first component. The process of preparing on an underlayer.

  (C ″) Step: Next, a step of removing the columnar substance.

  (D ″) Step: An oxidation step for oxidizing the porous body having columnar pores obtained by the removal step. For example, thermal oxidation is performed in an oxygen atmosphere. Note that the oxidation method is not only thermal oxidation in an oxygen atmosphere, but also thermal oxidation in a water vapor atmosphere. By this step, the porous body 56 in which the constituent members are oxidized is formed.

  (E ″) Step: Next, an introduction step of introducing the catalyst material into the pores of the porous body having columnar pores obtained by the oxidation step.

  (F ″) Step: Next, an introduction step of introducing carbon nanotubes into the pores of the porous body into which the catalyst metal has been introduced.

  Through these steps, a device using carbon nanotubes is formed.

  This example shows an example in which a carbon nanotube device in which the main component of a porous member having columnar holes forming carbon nanotubes is silicon oxide and the diameter of the carbon nanotubes is about 7 nm is formed. Here, an example is shown in which a device using carbon nanotubes is used as the electron-emitting device.

  First, an aluminum silicon mixed film containing 45 atomic% of silicon with respect to the total amount of aluminum and silicon is formed on a silicon substrate on which tungsten is deposited by 20 nanometers as an electrode for electrodepositing a catalytic metal by using a magnetron sputtering method. A thickness of about 500 nm was formed. A circular aluminum silicon mixed target having a diameter of 4 inches (101.6 mm) was used as the target. As the aluminum silicon mixed target, an aluminum powder and silicon powder sintered at a ratio of 55 atomic%: 45 atomic% was used. Sputtering conditions were as follows: Ar flow rate: 30 sccm, discharge pressure: 0.1 Pa, input power: 100 W using an RF power source. The substrate temperature was 100 ° C.

  In addition, the aluminum silicon mixed film was observed with FE-SEM (field emission scanning electron microscope). As shown in FIG. 6A, the shape of the surface viewed from the obliquely upward direction of the substrate was a two-dimensional array of circular aluminum columnar structures surrounded by silicon regions. The average pore diameter of the aluminum columnar structure portion was 7 nm. Moreover, when the cross section was observed with FE-SEM, each aluminum columnar structure was mutually independent.

  The aluminum-silicon mixed film thus prepared is 5 wt. It was immersed in a% phosphoric acid solution for 24 hours, and only aluminum columnar structure portions were selectively etched to form pores. As a result, a porous film composed of a member mainly composed of silicon oxide was produced.

  Next, an aluminum silicon mixed film etched with phosphoric acid (a porous film composed of a member mainly composed of silicon oxide) was observed with FE-SEM. As shown in FIG. 6B, the surface shape viewed obliquely from above the substrate was such that the pores surrounded by silicon members were two-dimensionally arranged. The pore diameter was 7 nm.

  Next, Co as a catalyst material for growing carbon nanotubes was embedded in the pores. Here, an aqueous solution of cobalt sulfate (II) heptahydrate 0.2M and boric acid 0.3M was used for electrodeposition of Co at 24 ° C. Electrodeposition was performed at −2.0 V for 10 seconds using Ag / AgCl as a reference electrode in the above solution. As a result, Co as a catalyst material was slightly buried in the pores of the porous body as shown in FIG.

  Next, the carbon nanotubes were heated in acetylene to grow from Co in the pores. Here, 10 sccm of hydrogen gas, hydrogen diluted acetylene gas mixed with 98%: 2% of hydrogen and acetylene was introduced into the reaction vessel at 10 sccm, and the pressure was adjusted to 20 Pa. Then, the infrared lamp was turned on, the substrate temperature was adjusted to 700 ° C., and carbon nanotubes were grown for 30 minutes. As a result, a device using carbon nanotubes in which carbon nanotubes were grown from Co as a catalyst material as shown in FIG.

  Next, when the diameter of the carbon nanotube thus produced was measured, the diameter was about 7 nm.

Next, in order to characterize the device using the obtained carbon nanotube as shown in FIG. 3E, the device using the carbon nanotube was placed in a vacuum chamber, and the counter electrode was parallel to the substrate and the substrate. It was installed at a position 0.1 mm away from the substrate so as to face the carbon nanotube formation surface of the substrate. Then, after evacuating the chamber to 10 ⁻⁶ Pa, a positive voltage was applied to the counter electrode, and the amount of electron emission from the carbon nanotubes was measured. As a result, the emission current started to be observed after application of about 100V. Therefore, it was confirmed that the device using the carbon nanotube thus produced functions as an electron-emitting device.

  This example shows an example in which a carbon nanotube device in which the main component of a porous member having columnar holes forming carbon nanotubes is silicon except oxygen and the diameter of the carbon nanotube is about 5 nm is formed. . Here, an example is shown in which a device using carbon nanotubes is used as an infrared sensor.

  First, an aluminum silicon mixed film containing 50 atomic% of silicon with respect to the total amount of aluminum and silicon is formed on a silicon substrate on which tungsten is deposited by 20 nanometers as an electrode for electrodepositing a catalytic metal using a magnetron sputtering method. A thickness of about 500 nm was formed. A circular aluminum silicon mixed target having a diameter of 4 inches (101.6 mm) was used as the target. As the aluminum silicon mixed target, an aluminum powder and silicon powder sintered at a ratio of 50 atomic%: 50 atomic% was used. Sputtering conditions were as follows: Ar flow rate: 30 sccm, discharge pressure: 0.1 Pa, input power: 100 W using an RF power source. The substrate temperature was 100 ° C.

  In addition, the aluminum silicon mixed film was observed with FE-SEM. As shown in FIG. 6A, the shape of the surface viewed from the obliquely upward direction of the substrate was a circular aluminum columnar structure surrounded by silicon regions two-dimensionally arranged. The average pore diameter of the aluminum columnar structure portion was 5 nm. Moreover, when the cross section was observed with FE-SEM, each aluminum columnar structure was mutually independent.

  The aluminum silicon mixed film thus produced was immersed in a 98% concentrated sulfuric acid solution for 24 hours as shown in FIG. 4C ', and only the aluminum columnar structure portion was selectively etched to form pores. As a result, a porous film composed of a member mainly composed of silicon except for oxidation was produced. Note that the surface of the porous film was oxidized.

  Next, an aluminum silicon mixed film etched with concentrated sulfuric acid (a porous film composed of a silicon-based member) was observed with FE-SEM. As shown in FIG. 6B, the surface shape viewed obliquely from above the substrate was such that the pores surrounded by silicon members were two-dimensionally arranged. The average pore diameter of the pores was about 5 nm. In addition, the silicon which is the main component of the member was amorphous.

  Next, a porous film composed of a member whose main component excluding oxygen was silicon was annealed in hydrogen at 800 ° C. for 1 hour. As a result, amorphous silicon was crystallized to form a porous body made of polycrystalline silicon as shown in FIG.

  Next, Co as a catalyst material for growing carbon nanotubes was embedded in the pores. Here, an aqueous solution of cobalt sulfate (II) heptahydrate 0.2M and boric acid 0.3M was used for electrodeposition of Co at 24 ° C. Electrodeposition was performed at −2.0 V for 10 seconds using Ag / AgCl as a reference electrode in the above solution. As a result, Co was slightly buried in the pores of the porous body.

  Next, the carbon nanotubes were heated in acetylene to ease the Co in the pores. Here, 10 sccm of hydrogen gas and 10 sccm of hydrogen diluted acetylene gas mixed with 98%: 2% of hydrogen and acetylene were introduced into the reaction vessel, and the pressure was set to 20 Pa. Then, the infrared lamp was turned on, and carbon nanotubes were grown at a gas temperature of 700 ° C. for 30 minutes. As a result, a device using carbon nanotubes in which carbon nanotubes were grown from Co as a catalyst material was produced.

  Next, when the diameter of the carbon nanotube thus produced was measured, the diameter was about 5 nm.

  Next, in order to evaluate the characteristics of the device using the obtained carbon nanotube, electrodes were formed on both ends of the device using the carbon nanotube and irradiated with 4 μm infrared rays. As a result, it was confirmed that the resistance value before and after infrared irradiation changed greatly. Therefore, it was confirmed that the device using the carbon nanotube thus produced functions as an infrared sensor.

  This example shows an example in which a carbon nanotube device in which the main component of a porous member having columnar pores forming carbon nanotubes is germanium excluding oxygen and the diameter of the carbon nanotube is about 15 nm is formed. . Here, an example is shown in which a device using carbon nanotubes is used as an infrared sensor.

  First, an aluminum-germanium mixed film containing 35 atomic% of germanium with respect to the total amount of aluminum and germanium is formed on a silicon substrate on which tungsten is deposited by 20 nanometers as an electrode for electrodepositing a catalytic metal by using a magnetron sputtering method. A thickness of about 500 nm was formed. As a target, a circular aluminum germanium mixed target having a diameter of 4 inches (101.6 mm) was used. As the aluminum germanium mixed target, an aluminum 65 atomic% and germanium 35 atomic% melted simultaneously was used. Sputtering conditions were as follows: RF flow rate, Ar flow rate: 10 sccm, discharge pressure: 0.05 Pa, input power: 60 W. The substrate temperature was room temperature.

  In addition, the aluminum germanium mixed film was observed with FE-SEM. As shown in FIG. 6A, the shape of the surface viewed from the diagonally upward direction of the substrate was a circular aluminum columnar structure surrounded by a germanium region two-dimensionally arranged. The average pore diameter of the aluminum columnar structure portion was 15 nm. Moreover, when the cross section was observed with FE-SEM, each aluminum columnar structure was mutually independent.

  The aluminum germanium mixed film thus prepared was immersed in a 98% concentrated sulfuric acid solution for 24 hours as shown in FIG. 4 (c ′), and only aluminum columnar structure portions were selectively etched to form pores. As a result, a porous film composed of a member mainly composed of germanium except for oxidation was produced.

  Next, an aluminum germanium mixed film etched with concentrated sulfuric acid (a porous film composed of a member mainly composed of germanium) was observed with FE-SEM. As shown in FIG. 6B, the surface shape viewed obliquely from above the substrate was such that the pores surrounded by germanium members were two-dimensionally arranged. The average pore diameter of the pores was about 15 nm. In addition, germanium which is a main component of the member was amorphous.

  Next, Co as a catalyst material for growing carbon nanotubes was embedded in the pores. Here, an aqueous solution of cobalt sulfate (II) heptahydrate 0.2M and boric acid 0.3M was used for electrodeposition of Co at 24 ° C. Electrodeposition was performed at −2.0 V for 10 seconds using Ag / AgCl as a reference electrode in the above solution. As a result, Co was slightly buried in the pores of the porous body.

  Next, the carbon nanotubes were heated in acetylene to ease the Co in the pores. Here, 10 sccm of hydrogen gas and 10 sccm of hydrogen diluted acetylene gas mixed with 98%: 2% of hydrogen and acetylene were introduced into the reaction vessel, and the pressure was set to 20 Pa. Then, the infrared lamp was turned on, and carbon nanotubes were grown at a gas temperature of 700 ° C. for 30 minutes. As a result, a device using carbon nanotubes in which carbon nanotubes were grown from Co as a catalyst material as shown in FIG.

  Next, when the diameter of the carbon nanotube thus produced was measured, the diameter was about 15 nm.

Next, in order to characterize the obtained device using carbon nanotubes, the device using carbon nanotubes was placed in a vacuum chamber, and the counter electrode was parallel to the substrate and 0.1 mm away from the substrate. The substrate was placed so as to face the carbon nanotube formation surface of the substrate. Then, after evacuating the chamber to 10 ⁻⁶ Pa, a positive voltage was applied to the counter electrode, and the amount of electron emission from the carbon nanotubes was measured. As a result, the emission current started to be observed after applying about 120V. Therefore, it was confirmed that the device using the carbon nanotube thus produced functions as an electron-emitting device.

  In this example, a carbon nanotube device in which the main component of a porous member having columnar pores forming carbon nanotubes is silicon and germanium excluding oxygen, and the diameter of the carbon nanotube is about 10 nm is formed. Indicates. Here, an example is shown in which a device using carbon nanotubes is used as an infrared sensor.

  First, using a magnetron sputtering method on a silicon substrate on which 20 nm of tungsten is deposited as an electrode for electrodepositing a catalytic metal, a germanium / silicon composite is 40 atomic% with respect to the total amount of aluminum, silicon and germanium. An aluminum silicon germanium mixed film including silicon (20 atomic% silicon and 20 atomic% germanium) was formed to a thickness of about 500 nm. As the target, a circular aluminum silicon germanium mixed target having a diameter of 4 inches (101.6 mm) was used. The aluminum silicon germanium mixed target used was a sintered aluminum powder 60 atomic%, silicon powder 30 atomic%, and germanium powder 10 atomic%. Sputtering conditions were as follows: Ar flow rate: 30 sccm, discharge pressure: 0.1 Pa, input power: 100 W using an RF power source. The substrate temperature was 100 ° C.

  In addition, the aluminum silicon germanium mixed film was observed with FE-SEM. As shown in FIG. 6A, the shape of the surface seen from the diagonally upward direction of the substrate was a two-dimensional array of circular aluminum columnar structures surrounded by a composite region of silicon and germanium. The average pore diameter of the aluminum columnar structure portion was 10 nm. Moreover, when the cross section was observed with FE-SEM, each aluminum columnar structure was mutually independent.

  The aluminum silicon germanium mixed film thus prepared was immersed in a 98% concentrated sulfuric acid solution for 24 hours, and only aluminum columnar structure portions were selectively etched to form pores. As a result, a porous film composed of a member mainly composed of a composite of silicon and germanium except for oxidation was produced.

  Next, an aluminum silicon germanium mixed film etched with concentrated sulfuric acid (a porous film composed of a member whose main components excluding oxygen are silicon and germanium) was observed with FE-SEM. As shown in FIG. 6B, the surface shape viewed obliquely from the upper side of the substrate was two-dimensionally arranged with pores surrounded by a member mainly composed of a composite of silicon and germanium. The average pore diameter of the pores was about 10 nm. The composite of silicon and germanium, which is the main component of the member, was amorphous.

  Next, a porous film composed of a member whose main component excluding oxygen was a composite of silicon and germanium was annealed in hydrogen at 800 ° C. for 1 hour. As a result, a composite of amorphous silicon and germanium was crystallized to form a porous body made of polycrystalline silicon germanium. The porous body made of crystallized silicon germanium exhibited p-type semiconductor characteristics.

  Next, Co as a catalyst material for growing carbon nanotubes was embedded in the pores. Here, an aqueous solution of cobalt sulfate (II) heptahydrate 0.2M and boric acid 0.3M was used for electrodeposition of Co at 24 ° C. Electrodeposition was performed at −2.0 V for 10 seconds using Ag / AgCl as a reference electrode in the above solution. As a result, Co was slightly buried in the pores of the porous body.

  Next, the carbon nanotubes were heated in acetylene to ease the Co in the pores. Here, 10 sccm of hydrogen gas and 10 sccm of hydrogen diluted acetylene gas mixed with 98%: 2% of hydrogen and acetylene were introduced into the reaction vessel, and the pressure was set to 20 Pa. Then, the infrared lamp was turned on, and carbon nanotubes were grown at a gas temperature of 700 ° C. for 30 minutes. As a result, a device using carbon nanotubes in which carbon nanotubes were grown from Co as a catalyst material as shown in FIG.

  Next, when the diameter of the carbon nanotube thus produced was measured, the diameter was about 10 nm.

Next, in order to characterize the obtained device using carbon nanotubes, the device using carbon nanotubes was placed in a vacuum chamber, and the counter electrode was parallel to the substrate and 0.1 mm away from the substrate. The substrate was placed so as to face the carbon nanotube formation surface of the substrate. Then, after evacuating the chamber to 10 ⁻⁶ Pa, a positive voltage was applied to the counter electrode, and the amount of electron emission from the carbon nanotubes was measured. As a result, the emission current started to be observed after applying about 110V. Therefore, it was confirmed that the device using the carbon nanotube thus produced functions as an electron-emitting device.

It is the schematic which shows an example of the carbon nanotube device of this invention. It is process drawing which shows one Embodiment of the manufacturing method of the carbon nanotube device of this invention. It is process drawing which shows one Embodiment of the manufacturing method of the carbon nanotube device of this invention. It is process drawing which shows other embodiment of the manufacturing method of the carbon nanotube device of this invention. It is process drawing which shows other embodiment of the manufacturing method of the carbon nanotube device of this invention. It is explanatory drawing which shows an example of the manufacturing method of the porous body of this invention. It is process drawing which shows other embodiment of the manufacturing method of the carbon nanotube device of this invention. It is process drawing which shows other embodiment of the manufacturing method of the carbon nanotube device of this invention.

Explanation of symbols

11, 28, 39, 59 Carbon nanotube device 12, 27, 38, 58 Carbon nanotube 13, 21, 31, 41, 51 Substrate 14, 25, 35, 36, 55, 56 Porous material 15, 26, 37, 57 Catalyst material 16, 22, 32, 52 Underlayer 23, 33, 44, 53 Mixed film 24, 34, 45, 54 Pore 42 Second component 43 capable of forming eutectic with first component 43 First component (aluminum)

Claims (10)

A device having carbon nanotubes retained in the pores of a porous body having columnar pores,
The porous body includes a structure in which a columnar substance including a first component is dispersed in a member including a second component capable of forming a eutectic with the first component. A device using carbon nanotubes, wherein the device is formed by removing the columnar substance.   The device using carbon nanotubes according to claim 1, wherein the porous body is a thin film.   The first component is aluminum, the second component is a semiconductor material, and a ratio of the semiconductor material in the structure is in a range of 20 atomic% to 70 atomic%. A device using the carbon nanotube according to 1 or 2.   4. The device using carbon nanotubes according to claim 3, wherein the semiconductor material is any one of silicon, germanium, and a composite of silicon and germanium.   The average diameter of the said columnar hole is 1 nanometer or more and less than 20 nanometer, The device using the carbon nanotube in any one of Claims 1-4 characterized by the above-mentioned. 6. The device using carbon nanotubes according to claim 1, wherein an average density of the columnar vacancies is 1.5 × 10 ¹¹ pieces / cm ² or more. Providing a structure in which a columnar substance including a first component is dispersed in a member including a second component capable of forming a eutectic with the first component; and
A removal step of removing the columnar substance;
Introducing a catalyst material into the pores of the porous body having columnar pores obtained by the removing step;
And a step of introducing a carbon nanotube into the pores of the porous body into which the catalyst material has been introduced. Providing a structure in which a columnar substance including a first component is dispersed in a member including a second component capable of forming a eutectic with the first component; and
A removal step of removing the columnar substance;
A crystallization step of crystallizing a porous body having columnar pores obtained by the removal step;
Introducing a catalyst material into the pores of the porous body produced by the crystallization step;
And a step of introducing a carbon nanotube into the pores of the porous body into which the catalyst material has been introduced. Providing a structure in which a columnar substance including a first component is dispersed in a member including a second component capable of forming a eutectic with the first component; and
A removal step of removing the columnar substance;
Oxidizing the porous body having columnar pores obtained by the removing step;
Introducing a catalyst material into the pores of the porous oxide material produced by the oxidation step;
And a step of introducing a carbon nanotube into the pores of the porous body into which the catalyst material has been introduced. The first component is aluminum, and the second component is a semiconductor material of silicon, germanium, or a composite of silicon and germanium. A device manufacturing method using carbon nanotubes.

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