Patent Application
20250033980
The present invention relates to a composition containing only nanowires.
Today, nanowires are attracting attention as a material that improves performance of semiconductor devices, sensors, solar cells, lithium ion batteries, or other devices. The above-mentioned nanowires have been used in various applications.
For instance, Patent Literature 1 describes an electrode material for an electrochemical device, in which electrode material, a plurality of silicon nanowires containing silicon are disposed to a plurality of independent particles containing silicon, the silicon nanowires are entangled with each other to form a silicon nanowire network, and the independent particles and the silicon nanowire network occlude lithium.
The independent particles are joined to each other in the silicon nanowire network, and the independent particles and the silicon nanowires have diameters of about 0.5 to 10 μm and about 10 nm to 500 nm, respectively. The silicon nanowire network is formed on a support.
Patent Literature 2 describes a solar cell including a substrate, a first ++ type polycrystalline silicon layer provided on the substrate, a first type silicon nanowire layer containing a first type silicon nanowire that has grown from the first ++ type polycrystalline silicon layer, an intrinsic layer formed on the substrate having the first type silicon nanowire layer, and a second type doping layer formed on the intrinsic layer.
Patent Literature 2 also describes a method for forming silicon nanowires, the method including a first ++ type polycrystalline silicon layer forming step of forming a first ++ type polycrystalline silicon layer on a substrate, a metallic thin film layer forming step of forming a metallic thin film layer on the first ++ type polycrystalline silicon layer, a metallic nanoparticle forming step of forming metallic thin film layers on metallic nanoparticles, and a first type silicon nanowire growing step of growing first type silicon nanowires from the first ++ type polycrystalline silicon layer using the metallic nanoparticles as seeds.
Patent Literature 1: JP 2008-269827 A
Patent Literature 2: JP 2010-192870 A
The silicon nanowire network of Patent Literature 1 is not independent from but formed on a support; the silicon nanowire network is not present by itself. Patent Literature 2 describes the first type silicon nanowire layer formed on a substrate and does not describe independent nanowires. If nanowires alone are produced by scraping the nanowire layer off from the substrate, nanowires are crushed and cannot be independently collected. As described above, at present, there are no nanowires that do not essentially require a carrier such as a substrate and are present all by themselves.
The present invention aims at providing a composition containing only nanowires that do not essentially require a carrier such as a substrate.
In order to attain the above-described object, an embodiment of the present invention provides a composition containing only nanowires, wherein the nanowires have a diameter of not less than 1 nm and less than 40 nm and are formed of at least one of Si or SiO.
The nanowires preferably have a length of at least three times the diameter.
The invention can provide a composition containing only nanowires that do not essentially require a carrier such as a substrate. Since the nanowires are present as nanowires alone, an operation of separating or extracting nanowires is not required, thereby enabling easy handling.
On the following pages, a composition of the invention is described in detail with reference to a preferred embodiment shown in the accompanying drawings.
It should be noted that the drawings described below are illustrative to explain the invention, and the invention is not construed to be limited to the drawings described below.
A composition production apparatus 10 (hereinafter, referred to simply as “production apparatus 10”) shown in
As the feedstock for the composition containing only nanowires, for instance, SiO (silicon monoxide) or SiOx (where 0<x<2, x≠1) is used.
The feedstock for the composition containing only nanowires takes a form of powder, for example, and the feedstock powder is supplied to the production apparatus 10 by use of carrier gas. Argon gas, helium gas, and mixed gas of argon gas and oxygen gas are usable as the carrier gas, for example.
The composition contains only nanowires as described above, and the nanowires do not essentially require a carrier such as a substrate. In the composition, since the nanowires are independently present, an operation of separating or extracting the nanowires is not required, and the nanowires allow easy handling. Hence, the nanowires are applicable in a wide variety of applications.
The nanowires are formed of at least one of Si or SiO.
The nanowires have a diameter of not less than 1 nm and less than 40 nm. The nanowires are wire-shaped objects having a longer length than that of a particulate shape. The nanowires preferably have a length of at least three times the diameter thereof. The upper limit of the length of the nanowires is not particularly limited as long as the length is at least three times the diameter, and is, for example, subjected to production restriction or other restrictions.
The diameter of the nanowires represents an average value of nanowire diameters obtained by acquiring multiple images of nanowires using a scanning electron microscope (SEM) and measuring diameters of 500 nanowires in total that are randomly extracted from three to five SEM images. The average value of diameters can be also obtained by analyzing three to five SEM images and measuring diameters of regions equivalent to diameters of 500 nanowires in total that are randomly extracted.
The length of the nanowires represents an average value of nanowire lengths obtained by acquiring multiple images of nanowires using an SEM and measuring lengths of 500 nanowires in total that are randomly extracted from three to five SEM images. The average value of lengths can be also obtained by analyzing three to five SEM images and measuring lengths of regions equivalent to lengths of 500 nanowires in total that are randomly selected.
The nanowires may carry on their surfaces or may be coated with a substance such as carbon aside from constituents of the nanowires, as with the nanoparticles described above.
Here, “containing only nanowires” means containing no particles nor other wires that are not nanowires. Specifically, nanoparticles or nanorods are not contained. The state of “containing only nanowires” is shown in
The nanoparticles are nanosized fine particles and have a particle size of not more than 100 nm. The particle size of the nanoparticles is preferably 10 to 100 nm. The nanoparticles are preferably spherical but are not limited to a spherical shape. For instance, the nanoparticles are defined to have a ratio β/α of less than 3, provided that the minor axis diameter is α and the major axis diameter is β.
The particle size of the nanoparticles represents an average value of fine particle sizes obtained by acquiring plural SEM images of fine particles using a scanning electron microscope (SEM) and measuring particle sizes of 500 fine particles in total that are randomly extracted from three to five SEM images. The average value of particle sizes can be also obtained by analyzing three to five SEM images, randomly extracting 500 fine particles in total, and, while regarding the 500 fine particles as spheres, measuring diameters of regions equivalent to the spheres.
The nanoparticles include those having the ratio β/α of less than 3 as described above. Hence, also of non-spherical fine particles, the minor axis-equivalent length and the major axis-equivalent length are measured, and the ratio β/α is obtained.
The nanoparticles may carry on their surfaces or may be coated with a substance such as carbon aside from constituents of the nanoparticles.
The nanorods are defined to have a diameter of not less than 40 nm and not more than 80 nm and a length of at least three times the diameter. The upper limit of the length of the nanorods is not particularly limited as long as the length is at least three times the diameter, and is, for example, subjected to production restriction or other restrictions. The nanorods are wire-shaped objects having a larger diameter than that of the nanowires.
The diameter of the nanorods represents an average value of nanorod diameters obtained by acquiring multiple SEM images of nanorods using an SEM and measuring diameters of 500 nanorods in total that are randomly extracted from three to five SEM images. The average value of diameters can be also obtained by analyzing three to five SEM images and measuring diameters of regions equivalent to diameters of 500 nanorods in total that are randomly extracted.
The length of the nanorods represents an average value of nanorod lengths obtained by acquiring multiple images of nanorods using an SEM and measuring lengths of 500 nanorods in total that are randomly extracted from three to five SEM images. The average value of lengths can be also obtained by analyzing three to five SEM images and measuring lengths of regions equivalent to lengths of 500 nanorods in total that are randomly extracted.
The nanorods may carry on their surfaces or may be coated with a substance such as carbon aside from constituents of the nanorods, as with the nanoparticles described above.
Hereinafter, the production apparatus 10 shown in
The production apparatus 10 shown in
The feedstock supply section 12 is connected to the plasma torch 14 through a hollow supply tube 13.
Between the feedstock supply section 12 and the plasma torch 14, disposed is an intermittent supply section 15 as described later. The feedstock supply section 12 is connected to the intermittent supply section 15 that is disposed above the plasma torch 14 through the supply tube 13.
The chamber 16 is disposed below the plasma torch 14, and the collection section 18 is disposed at the chamber 16. The plasma generation section 21 is connected to the plasma torch 14, and a thermal plasma flame 100 (see
The feedstock supply section 12 is configured to supply feedstock for the composition into the thermal plasma flame 100 generated in the plasma torch 14. The feedstock supply section 12 is not particularly limited as long as it can supply feedstock for the composition into the thermal plasma flame 100.
In a case where SiO or SiOx powder is used as the feedstock for the composition (hereinafter, the feedstock for the composition may be simply referred to as “feedstock”), the feedstock needs to be dispersed in a particulate form when supplied into the thermal plasma flame 100 in the plasma torch 14. Therefore, the feedstock is, for instance, dispersed in carrier gas so that the feedstock in a particulate form is supplied. In this case, the feedstock supply section 12 supplies the powdery feedstock in a particulate state into the thermal plasma flame 100 in the plasma torch 14 whilst maintaining the feedstock to be in a dispersed state, for example. For the feedstock supply section 12 having such a function, usable examples include devices disclosed in JP 3217415 B and JP 2007-138287 A.
For example, the feedstock supply section 12 includes a storage tank (not shown) storing feedstock powder, a screw feeder (not shown) transporting the feedstock powder in a fixed amount, a dispersion section (not shown) dispersing the feedstock powder transported by the screw feeder into a particulate form before the feedstock powder is finally sprayed, and a carrier gas supply source (not shown).
Together with carrier gas to which push-out pressure is applied from the carrier gas supply source, the feedstock powder is supplied into the thermal plasma flame 100 in the plasma torch 14 through the supply tube 13.
The configuration of the feedstock supply section 12 is not particularly limited as long as the feedstock supply section 12 can prevent the feedstock powder from agglomerating and spray the feedstock powder into the plasma torch 14 with the feedstock powder being dispersed in a particulate form and the dispersed state being maintained. As the carrier gas, for example, not only argon gas (Ar gas) but helium gas and mixed gas of argon gas and oxygen gas are usable.
As described above, examples of the feedstock for the composition include SiO or SiOx, and, for example, SiO or SiOx powder is used. SiO or SiOx powder is appropriately designed to have an average particle size which allows easy evaporation of the powder in a thermal plasma flame. The average particle size of SiO or SiOx powder has, for example, d50 of not more than 100 μm, preferably not more than 10 μm, and more preferably not more than 5 μm.
The average particle size d50 of SiO or SiOx powder represents a median in a particle size frequency distribution.
The plasma torch 14 is configured to allow the thermal plasma flame 100 to be generated therein and, by use of the thermal plasma flame 100, evaporate the feedstock supplied by the feedstock supply section 12 to transform the feedstock into a mixture 34 in a gas phase state.
As shown in
For instance, the powdery feedstock and the carrier gas such as argon gas are supplied into the plasma torch 14 through the supply tube 13.
The plasma gas supply port 14d is connected to the plasma gas supply section 20 via, for example, piping which is not shown. The plasma gas supply section 20 is configured to supply plasma gas into the plasma torch 14 through the plasma gas supply port 14d. For the plasma gas, gases such as argon gas and hydrogen gas are used alone or in combination as appropriate, for instance.
A sheath gas supply section 23 supplying sheath gas into the plasma torch 14 may be provided in addition to the plasma gas supply section 20. For the sheath gas, gases such as argon gas and hydrogen gas can be used alone or in combination as appropriate, for instance. The plasma gas supply section 20 and the sheath gas supply section 23 basically have the same configuration, and only gas type is different between them.
Hydrogen gas used for the plasma gas or the sheath gas has a large specific enthalpy and a large thermal conductivity. By mixing hydrogen gas with the plasma gas or the sheath gas, an improvement in evaporation efficiency of the feedstock powder is expected, and an effect of reducing oxygen from evaporated vapor of feedstock is obtained.
The outside of the quartz tube 14a of the plasma torch 14 is surrounded by a concentrically formed quartz tube 14e, and cooling water 14f is circulated between the quartz tubes 14a and 14e to cool the quartz tube 14a with the water, thereby preventing the quartz tube 14a from having an excessively high temperature due to the thermal plasma flame 100 generated in the plasma torch 14.
The intermittent supply section 15 is disposed between the feedstock supply section 12 and the plasma torch 14 and is connected to the supply tube 13. The intermittent supply section 15 is also connected to the pulse signal generator 22.
For the intermittent supply section 15, for instance, a solenoid valve (electromagnetic valve) is used. The intermittent supply section 15 time-modulates an amount of supply of the feedstock. The intermittent supply section 15 controls opening and closing of the solenoid valve in accordance with pulse signals output from the pulse signal generator 22.
It takes time after the solenoid valve is opened until the feedstock is actually transported and the amount of supply of the feedstock into the thermal plasma flame 100 increases, and therefore, the solenoid valve and the like need to be controlled taking the time required for the transportation into account.
A ball valve may be used instead of the solenoid valve for the intermittent supply section 15. Also in this case, the opening and closing of the ball valve is controlled in accordance with pulse signals output from the pulse signal generator 22. As with the solenoid valve, the feedstock is actually transported after the ball valve is opened, and therefore, the ball valve needs to be controlled taking the time required for the transportation into account.
The plasma generation section 21 is provided to generate the thermal plasma flame 100 in the plasma torch 14 as described above. The plasma generation section 21 includes a first coil 32 surrounding the periphery of the plasma torch 14, a second coil 33 surrounding the periphery of the plasma torch 14, a first power source section 21a supplying high frequency current to the first coil 32, and a second power source section 21b supplying high frequency current to the second coil 33. The high frequency current supplied to the first coil 32 is also called first coil current, and the high frequency current supplied to the second coil 33 is also called second coil current.
The first coil 32 and the second coil 33 are arranged side by side in the longitudinal direction of the plasma torch 14, and the second coil 33 is disposed under the first coil 32.
The first power source section 21a and the second power source section 21b are both high frequency power sources and are independent of each other. It is preferable that the frequency of high frequency current of the first power source section 21a and the frequency of high frequency current of the second power source section 21b be different from each other in order to reduce magnetic coupling between the first coil 32 and the second coil 33. This configuration can suppress the influence of the power source sections on each other.
The first coil 32 and the second coil 33 constitute the high frequency oscillation coil 14b. The numbers of turns of the first coil 32 and the second coil 33 are not particularly limited and suitably determined depending on the configuration of the production apparatus 10. Materials of the first coil 32 and the second coil 33 are also not particularly limited and suitably determined depending on the configuration of the production apparatus 10.
With the use of the two coils and the two independent power source sections in the plasma generation section 21, a series structure of induction thermal plasma can be built. The provision of the series structure of induction thermal plasma makes it possible to generate a high-temperature field that is long in the axial direction of the plasma torch 14. When the long high-temperature field as above is used, it is possible to completely evaporate a high melting point material. A thermal plasma flame that is periodically switched between a high temperature state and a low temperature state having a lower temperature than that in the high temperature state at predetermined time intervals, i.e., that is time-modulated in terms of the temperature state, is called a modulated induction thermal plasma flame.
For instance, the plasma generation section 21 supplies at least one of the first coil 32 or the second coil 33 with unmodulated high frequency current that is not subjected to amplitude modulation (see
The plasma generation section 21 also supplies at least one of the first coil 31 or the second coil 33 with amplitude-modulated high frequency current (see
For instance, when unmodulated high frequency current (see
It should be noted that by supplying unmodulated high frequency current to the first coil 32 to generate the thermal plasma flame 100, it is possible to stabilize the thermal plasma flame 100, and destabilization of the thermal plasma flame 100 can be suppressed even when high frequency current supplied to the second coil 33 is modulated. This configuration makes it possible to suppress a decrease in the temperature of the thermal plasma flame 100 even when, for instance, a large amount of feedstock is supplied to the thermal plasma flame 100.
In the plasma generation section 21, the high frequency current supplied to the first coil 32 and the second coil 33 can be either unmodulated high frequency current that is not subjected to amplitude modulation (see
In the amplitude-modulated high frequency current, the high value of the current amplitude is defined as a higher current level (HCL), the low value of the current amplitude is defined as a lower current level (LCL), and the time with HCL and the time with LCL in one modulation cycle are respectively defined as the ON time and the OFF time. Further, the percentage of the ON time in one cycle: (ON time/(ON time+OFF time)×100 (%)) is defined as a duty factor (DF). The ratio (LCL/HCL×100 (%)) in the amplitude is defined as a current modulation ratio (SCL).
The current modulation ratio (SCL) represents the degree of modulation of current amplitude, where 100% SCL represents an unmodulated state and 0% SCL represents that the current amplitude is most largely modulated. At 0% SCL, the current value of high frequency current is 0 ampere (A) during the OFF time, i.e., in a region where the current amplitude of high frequency current is low, which will be described later. The amplitude modulation is not particularly limited as long as the SCL value is not less than 0% SCL and less than 100% SCL, and 0% SCL is most preferable because a value closer to 0% SCL refers to a higher degree of modulation, i.e., larger amplitude modulation.
The ON time (see
The ambient pressure inside the plasma torch 14 is suitably determined depending on production conditions of fine particles and is, for example, not higher than the atmospheric pressure. The atmosphere with a pressure of not higher than the atmospheric pressure is not particularly limited, and for example, the pressure may range from 5 Torr (666.5 Pa) to 750 Torr (99.975 kPa).
As to the chamber 16, as shown in
The chamber 16 serves as a cooling tank, and the composition (not shown), i.e., the nanowires are generated in the chamber 16.
The collection section 18 includes a collection chamber having the filter 18a, and a vacuum pump 18b connected through a pipe provided at a lower portion of the collection chamber. The fine particles transported from the chamber 16 are sucked by the vacuum pump 18b to be introduced into the collection chamber, and those fine particles remaining on the surface of the filter 18a are collected.
The first power source section 21a and the second power source section 21b of the plasma generation section 21 are specifically described.
Since the first power source section 21a and the second power source section 21b have the same configuration, the first power source section 21a is described while detailed description of the second power source section 21b is omitted.
As shown in
The RF power source 30a serves as an input power source and makes use of, for example, a three-phase alternating current power source.
The rectifier circuit 30b performs alternating current-direct current conversion and makes use of, for example, a three-phase full-wave rectifier circuit.
The DC-DC converter 30c changes the output voltage value and makes use of, for example, an insulated gate bipolar transistor (IGBT).
The high frequency inverter 30d converts a direct current into an alternating current, has the function of modulating the amplitude of electric current, and can amplitude-modulate a coil current. The high frequency inverter 30d makes use of, for example, a metal oxide semiconductor field effect transistor (MOSFET) inverter.
The output side of the high frequency inverter 30d is connected with the impedance matching circuit 30e. The impedance matching circuit 30e is constituted of, for example, a series resonant circuit composed of a capacitor and a resonant coil and carries out impedance matching such that a resonance frequency of load impedance including plasma load falls within a drive frequency range of the high frequency inverter 30d.
The PWM controller 30f modulates current amplitude in accordance with a modulation signal based on the pulse control signal generated by the pulse signal generator 22 and includes, for example, an FET gate signal circuit (not shown). The PWM controller 30f is connected with the DC-DC converter 30c. The PWM controller 30f is also connected with the pulse signal generator 22.
The pulse signal generator 22 generates a pulse control signal for adding square wave modulation to the amplitude of the coil current used to maintain high frequency modulated induction thermal plasma. The PWM controller 30f obtains, from the pulse control signal, a modulation signal for modulating the current amplitude.
The PWM controller 30f supplies a modulation signal based on a pulse control signal generated by the pulse signal generator 22 to the DC-DC converter 30c and modulates the current amplitude by, for example, switching the IGBT. In this manner, in the first power source section 21a, the coil current can be amplitude-modulated by use of the modulation signal based on the pulse control signal generated by the pulse signal generator 22 such that the amplitude relatively increases or decreases, and for example, the coil current can be pulse-modulated as shown in
When the feedstock is intermittently supplied, the feedstock is supplied in synchronization with the high temperature state of the thermal plasma flame 100 so that the feedstock is completely evaporated in the high temperature state to have the mixture 34 in a gas phase state (see
The first power source section 21a makes use of, for example, a three-phase alternating current power source as the input power source, and after the alternating current-direct current conversion is performed through a three-phase full-wave rectifier circuit, the output value thereof is changed through the DC-DC converter 30c. The high frequency inverter 30d then converts a direct current that has been obtained by the rectifier circuit 30b and that has gone through the DC-DC converter 30c into an alternating current. By supplying the modulation signal based on the pulse control signal to the DC-DC converter 30c and switching the IGBT as described above, an inverter output, i.e., a coil current is amplitude-modulated (AM modulated). The impedance matching circuit 30e carries out impedance matching such that a resonance frequency of load impedance including plasma load falls within a drive frequency range of the high frequency inverter 30d as described above.
In addition, the second power source section 21b has the same configuration as that of the first power source section 21a and can pulse modulate the coil current as with the first power source section 21a. The first power source section 21a and the second power source section 21b can have the coil current unmodulated. In this case, for example, the pulse signal generator 22 does not input a pulse control signal.
In
The feedstock is supplied when the thermal plasma flame 100 is in the high temperature state and is not supplied when the thermal plasma flame 100 is in the low temperature state. The feedstock can be efficiently evaporated, and evaporated vapor can be cooled in this manner. By increasing the modulation of high frequency current of the second coil, the evaporated vapor can be better cooled.
Hereinafter, a composition production method using the foregoing production apparatus 10 is described. The composition production method is not limited to a method using the production apparatus 10.
First, as the feedstock powder for the composition, for instance, SiO or SiOx powder having d50 of 5 μm is prepared.
Argon gas is used as the plasma gas, for example, and a high frequency voltage is applied to the high frequency oscillation coil 14b (see
Next, the SiO or SiOx powder is transported with, for example, argon gas used as the carrier gas and supplied into the thermal plasma flame 100 in the plasma torch 14 through the supply tube 13. At that time, hydrogen gas is supplied as the sheath gas.
The thermal plasma flame is generated in the plasma torch 14, and at this time, while the first coil does not have the coil current modulated, the second coil has the coil current modulated to thereby modulate the temperature state of the thermal plasma flame 100. In this process, the supply amount of the feedstock is also changed such that when the temperature of the thermal plasma flame 100 is low, the supply of the feedstock powder is stopped, and when the temperature of the thermal plasma flame 100 is high, the feedstock powder is supplied to be vaporized.
The supplied SiO or SiOx powder is evaporated in the thermal plasma flame 100 and becomes the mixture 34 in a gas phase state (see
The nanowires obtained in the chamber 16 do not essentially require a carrier such as a substrate and are collected on the filter 18a of the collection section 18 owing to negative pressure (suction force) applied from the collection section 18 by the vacuum pump 18b, as described above. The nanowires are not in the form of being fixed onto a substrate but are present by themselves. Therefore, an operation of separating or extracting the nanowires is not required, and the nanowires allow easy handling and are applicable in a wide variety of applications.
The mechanism by which nanoparticles, nanorods, and nanowires are generated is described below. In particular, the mechanism of nucleus generation of an SiO-based material was studied in terms of thermodynamics.
In the meantime,
Applications of the composition containing the nanoparticles, the nanorods, and the nanowires include, for example, a negative electrode material of a lithium ion battery, a flexible device such as a sensor which functions as an electronic skin, a solar cell, a data storage device, and a light-emitting diode.
The present invention is basically configured as above. While the mixture production apparatus and the mixture production method according to the invention are described above in detail, the invention is by no means limited to the foregoing embodiments and it should be understood that various improvements and modifications are possible without departing from the scope and spirit of the invention.
The composition of the invention is more specifically described below.
In the present example, production of the composition containing only nanowires was attempted (Experimental Example 1). The production apparatus 10 shown in
As a production condition, SiO powder having d50 of 5 μm was used. The average particle size of the SiO powder is a value measured with a particle size distribution meter. It should be noted that d50 refers to a median of the particle size distribution of SiO powder.
In supplying the feedstock, Ar gas was used as the carrier gas, and the feedstock was supplied at a rate of 1.53 g/minute together with the carrier gas. The plasma was modulated as described later, and when the plasma was in the high temperature state, the feedstock was supplied, whereas when the plasma was in the low temperature state, the feedstock supply was stopped.
The flow rate of the carrier gas was 4 L/minute (as being converted to standard conditions).
Ar gas and hydrogen gas were used as the sheath gas, the flow rate of Ar gas was 90 L/minute (as being converted to standard conditions), and the flow rate of H2 gas was 1.5 slpm (=1.5 L/minute (as being converted to standard conditions)).
The average input power to the first coil was constant at 15 kW, and the frequency was 400 kHz. The average input power to the second coil was 10 kW, and the frequency was 200 KHz.
The first coil and the second coil each had eight turns. The pressure inside the chamber was set to 300 torr (≃40 kPa). The modulation cycle was 15 ms.
The foregoing sheath gas serves as the plasma gas. No quenching gas was used.
The plasma was modulated in Experimental Example 1. While the first coil current was unmodulated, the second coil current had a duty factor (DF) of 66% and a current modulation ratio (SCL) of 10%.
In Experimental Example 1, four SEM images were acquired, 500 wire-shaped objects in total were randomly extracted from the four SEM images, and the diameter of a region equivalent to each of the 500 wire-shaped objects was measured. As a result, the diameter frequency distribution shown in
As shown in
In Experimental Example 1, the diameter fell within the range of not less than 1 nm and less than 40 nm as shown in
In Experimental Example 1, the crystal structure analysis was performed using X-ray diffractometry (XRD). The result is shown in
The XRD spectrum shown in
In addition, the wire-shaped objects were observed in the SEM images shown in
In view of the diameter range (not less than 1 nm and less than 40 nm) shown in
In comparison with Experimental Example 1, Reference Example 1 is described below.
Reference Example 1 relates to a composition containing nanoparticles and nanorods aside from nanowires. Reference Example 1 has the diameter frequency distribution shown in
Reference Example 1 adopted the same production process as that in Experimental Example 1 except that the second coil current was unmodulated, compared to Experimental Example 1.
In view of the SEM image shown in
The diameter frequency distribution of Experimental Example 1 where only nanowires are contained (see
Furthermore, in view of the SEM image of Experimental Example 1 of
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-194762 | Nov 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/042520 | 11/16/2022 | WO |
