Particle-immobilized substrate, method for manufacturing a particle-immobilized substrate, method for manufacturing a diamond film-immobilized substrate, and method for manufacturing diamond.

Abstract

This invention provides a particle-immobilized substrate that can be easily fabricated and in which inorganic nanoparticles exist in the nanometer-scale region. It also provides a method for easily manufacturing a substrate in which nanoparticles are arranged in the nanometer-scale region on a solid surface. [Solution] The particle-immobilizing substrate 1 comprises a substrate 2 and a plurality of inorganic nanoparticles 3 arranged on the substrate 2, wherein the plurality of inorganic nanoparticles 3 are arranged in contact with each other within an area on the substrate 2 with a width (D1) of 1 μm or less.

Description

Technical Field

[0001] The present disclosure relates to a particle-fixed substrate, a method for manufacturing the particle-fixed substrate, a method for manufacturing a diamond film-fixed substrate, and a method for manufacturing diamond. More specifically, the present disclosure relates to a particle-fixed substrate in which inorganic nanoparticles are fixed within a nanometer-scale region on a substrate, a method for manufacturing the particle-fixed substrate, a method for manufacturing a diamond film-fixed substrate using the particle-fixed substrate, and a method for manufacturing diamond using the diamond film-fixed substrate. This application claims the priority of Japanese Patent Application No. 2021-38087 filed in Japan on March 10, 2021 and Japanese Patent Application No. 2021-170513 filed in Japan on October 18, 2021, the contents of which are incorporated herein by reference.

Background Art

[0002] Inorganic nanoparticles such as nanodiamonds and metal nanoparticles may be used by selectively adhering their dispersion liquids to intended regions on the surface of a solid substrate by inkjet printing or the like. For example, metal nanoparticles such as silver nanoparticles can be fired even at low temperatures. Utilizing this property, metal nanoparticles are used to form electrodes and conductive circuit patterns on a substrate in the manufacture of various electronic devices. In addition, inorganic nanoparticles are also being considered for use in nanodevices by arranging them on the substrate surface. Substrates with inorganic nanoparticles arranged on their surfaces are expected to be applied to nanodevices in the semiconductor field such as thermoelectric conversion elements, solar cells, displays, memories, thin film transistors, and LSIs.

[0003] Conventionally, as a substrate with inorganic nanoparticles arranged on its surface, a substrate on which inorganic nanoparticles are adhered and deposited in an intended micrometer-scale region is known. However, in recent years, there has been a tendency to demand a technique for adhering inorganic nanoparticles to a nanometer-scale region on the surface of a solid substrate.

[0004] Patent Document 1 describes a method in which a nanoparticle solution containing nanoparticles to which polymer chains are attached is applied to a substrate, the solvent is removed to arrange the nanoparticles on the substrate, and then the polymer chains are removed from the polymer chain-attached nanoparticles on the substrate to arrange the nanoparticles. According to this method, on the substrate to which the nanoparticles from which the polymer chains have been removed are arranged, there are voids between each nanoparticle that originate from the polymer chains before removal, and each nanoparticle is individually scattered at equal intervals. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2015-103609 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, the method described in Patent Document 1 involves arranging nanoparticles to which polymer chains are attached. Thus, in order to arrange nanoparticles that are not to which polymer chains are attached, the method described in Patent Document 1 requires first to create nanoparticles to which polymer chains are attached. This makes the process of creating a substrate in which nanoparticles are arranged in a nanometer-scale region on a solid surface complicated.

[0007] Therefore, an object of this disclosure is to provide a particle-immobilized substrate that can be easily fabricated and in which inorganic nanoparticles exist in a nanometer-scale region. Another object of this disclosure is to provide a method for easily manufacturing a substrate in which nanoparticles are arranged in a nanometer-scale region on a solid surface. Yet another object of this disclosure is to provide a method for easily manufacturing a substrate in which a diamond film is immobilized on a solid surface, preferably in a nanometer-scale region. [Means for solving the problem]

[0008] This disclosure comprises a substrate and a plurality of inorganic nanoparticles disposed on the substrate. The present invention provides a particle-immobilized substrate in which the above-mentioned plurality of inorganic nanoparticles are arranged in contact with each other within an area of ​​less than 1 μm in width on the substrate.

[0009] Furthermore, this disclosure comprises a substrate and inorganic nanoparticles disposed on the substrate. The present invention provides a particle-immobilized substrate in which the potential difference between the zeta potential of the inorganic nanoparticles and the zeta potential of the substrate surface at the location where the inorganic nanoparticles are arranged is 30 mV or more.

[0010] Preferably, a plurality of regions with a width of 1 μm or less are regularly arranged on the substrate, and the inorganic nanoparticles are arranged within each of the plurality of regions with a width of 1 μm or less.

[0011] The above nanoparticles preferably contain nanodiamond particles.

[0012] Furthermore, this disclosure provides a method for manufacturing a particle-immobilized substrate, which involves arranging inorganic nanoparticles by electrostatic action in a region with a width of 1 μm or less located within the first region of a substrate having a first region and a second region in which the potential difference between their zeta potentials is 30 mV or more.

[0013] It is preferable that the zeta potential of one of the first and second regions is positive and the zeta potential of the other is negative.

[0014] Furthermore, this disclosure provides a method for manufacturing a particle-immobilized substrate, comprising a substrate having a first region and a second region in which one zeta potential is positive and the other zeta potential is negative, wherein inorganic nanoparticles are arranged by electrostatic action in a region with a width of 1 μm or less located within the first region.

[0015] On the substrate, the multiple first regions are arranged regularly, and it is preferable to place the inorganic nanoparticles within each of the multiple first regions.

[0016] The above inorganic nanoparticles preferably contain nanodiamond particles.

[0017] The present disclosure also provides a method for manufacturing a diamond film-fixed substrate, which includes a CVD process of growing the above nano-diamond particles by chemical vapor deposition on the above particle-fixed substrate using the above nano-diamond particles as seeds to form a diamond film on the above substrate.

[0018] In the above CVD process, it is preferable to form the diamond film within a region on the substrate having a width of 1 μm or less.

[0019] The present disclosure also provides a method for manufacturing diamond, which includes removing the above substrate from the above diamond film-fixed substrate to obtain a single independent solid of the above diamond film or diamond particles constituting the above diamond film.

Advantages of the Invention

[0020] According to the particle-fixed substrate of the present disclosure, it can be easily manufactured, and a fixed substrate in which inorganic nanoparticles are present in a nanometer-scale region can be provided. Also, according to the method for manufacturing the particle-fixed substrate of the present disclosure, the above particle-fixed substrate can be easily manufactured. Further, according to the method for manufacturing the diamond film-fixed substrate of the present disclosure, a substrate on which a diamond film is formed on the above substrate (particularly, a nanometer-scale region on the above substrate) can be easily manufactured.

Brief Description of the Drawings

[0021] [Figure 1] It is an enlarged schematic view of a particle-fixed substrate according to an embodiment of the present disclosure. [Figure 2] It is an enlarged schematic view of a particle-fixed substrate according to another embodiment of the present disclosure. [Figure 3] It is a schematic view showing an embodiment of a method for manufacturing a substrate having regions with different zeta potentials from each other. [Figure 4] It is a schematic view showing another embodiment of a method for manufacturing a substrate having regions with different zeta potentials from each other. [Figure 5]It is an enlarged schematic diagram of a diamond film fixed substrate according to an embodiment of the present disclosure. [Figure 6] It is an enlarged schematic diagram of a diamond film according to another embodiment of the present disclosure. [Figure 7] It is a microscopic photograph of the particle-fixed substrate produced in Example 1. [Figure 8] It is a microscopic photograph of the particle-fixed substrate produced in Example 2. [Figure 9] It is a microscopic photograph of the No. 1 diamond film fixed substrate produced in Example 3. [Figure 10] It is a microscopic photograph of the No. 2 diamond film fixed substrate produced in Example 3. [Figure 11] It is a microscopic photograph of the No. 3 diamond film fixed substrate produced in Example 3. [Figure 12] It is a microscopic photograph of the No. 4 diamond film fixed substrate produced in Example 3. [Figure 13] It is an atomic force microscope (AFM) photograph showing the location where the surface roughness of the No. 1 diamond film surface was measured. [Figure 14] It is an atomic force microscope (AFM) photograph showing the location where the height plot of the No. 1 diamond film was measured and the measurement results.

Mode for Carrying Out the Invention

[0022] [Particle-Fixed Substrate] The particle-fixed substrate according to an embodiment of the present disclosure includes at least a substrate and inorganic nanoparticles disposed on the substrate. The inorganic nanoparticles are disposed within a region on the substrate having a width of 1 μm or less. In the particle-fixed substrate according to an embodiment of the present disclosure, a plurality of inorganic nanoparticles are disposed in contact with each other within a region on the substrate having a width of 1 μm or less. Further, in the particle-fixed substrate according to another embodiment of the present disclosure, the potential difference between the zeta potential of the inorganic nanoparticles and the zeta potential of the substrate surface at the position where the inorganic nanoparticles are disposed is 30 mV or more. In this specification, the region having a width of 1 μm or less where the inorganic nanoparticles are disposed may be referred to as a "particle arrangement nano-region".

[0023] Figure 1 shows an enlarged schematic diagram of one embodiment of the particle-immobilizing substrate described above. The particle-immobilizing substrate 1 includes a substrate 2 and a plurality of inorganic nanoparticles 3. In the particle-immobilizing substrate 1, the plurality of inorganic nanoparticles 3 are arranged in a region (particle-arrangement nano region) on the substrate 2 with a width D1 of 1 μm or less and extending in the lateral direction (a direction perpendicular to the width D1), forming a single layer consisting only of inorganic nanoparticles 3 within the particle-arrangement nano region. Some of the inorganic nanoparticles 3 are in contact with each other. Furthermore, the potential difference between the zeta potential of the inorganic nanoparticles 3 and the zeta potential of the substrate 2 surface at the positions where the inorganic nanoparticles 3 are arranged is 30 mV or more. In addition, multiple regions with a width D1 extending in the lateral direction are arranged vertically at intervals of D2, forming a stripe pattern.

[0024] Figure 2 shows an enlarged schematic diagram of another embodiment of the particle-immobilizing substrate described above. The particle-immobilizing substrate 1 includes a substrate 2 and a plurality of inorganic nanoparticles 3. The difference from the particle-immobilizing substrate 1 shown in Figure 1 is that the plurality of inorganic nanoparticles 3 are not in contact with each other but are arranged regularly.

[0025] The width of the above particle arrangement in the nanoscale region is 1 μm or less, and can also be 600 nm or less, 300 nm or less, or 150 nm or less.

[0026] The above-mentioned particle arrangement nano-regions specifically include rectangles, other polygons, perfect circles, ellipses, wavy lines, diagonal lines (parallelograms), and irregular shapes, as shown in Figure 1. For rectangles, ellipses, wavy lines, and diagonal lines, it is obvious which length corresponds to the "width." For other shapes, if the shape extends in one direction and has a major axis and a minor axis, the minor axis shall be considered the "width." For shapes that do not have a distinction between major and minor axes, such as regular polygons and perfect circles, the longest diameter of the shape shall be considered the "width." In the case of shapes whose width varies, the shortest width of the shape may be considered the "width."

[0027] The above-described particle arrangement nanoregion may exist as a single entity on the substrate, or multiple entities may exist with the same or different shapes. Furthermore, the above-described particle arrangement nanoregions may be arranged regularly (arranged) or irregularly, but a regular arrangement is preferred. Patterns represented by a regular arrangement include stripe patterns, dot patterns, checkered patterns, grid patterns, houndstooth patterns, and mesh patterns. The shape of the dots in a dot pattern is not particularly limited and includes plus signs, circles, polygons, etc.

[0028] The spacing between the multiple particle arrangement regions in the regularly arranged shapes such as the stripe pattern or dot pattern described above (for example, D2 in Figure 1) is not particularly limited, but is preferably 0.1 to 1.5 times the width length, and more preferably 0.5 to 1.0 times.

[0029] The inorganic nanoparticles described above are arranged within a region on the substrate with a width of 1 μm or less (a nanoparticle arrangement region). When multiple inorganic nanoparticles are arranged within the nanoparticle arrangement region, some or all of the multiple inorganic nanoparticles may be in contact with each other within the region on the substrate with a width of 1 μm or less. In this case, two inorganic nanoparticles in contact with the substrate may also be in contact with each other.

[0030] In the particle-fixed substrate described above, the plurality of inorganic nanoparticles can form a single layer of particles (a layer consisting only of inorganic nanoparticles, without other components such as resin components). The single layer may be a layer in which inorganic nanoparticles are not stacked in the height direction (a single layer of inorganic nanoparticles), or it may be a layer in which inorganic nanoparticles are stacked in the height direction (a multilayer of inorganic nanoparticles). If there are multiple nano-regions with the above particle arrangement, the single layer of inorganic nanoparticles and the multilayer of inorganic nanoparticles may be mixed in these multiple regions.

[0031] The presence of inorganic nanoparticles within a region less than 1 μm wide and the contact between multiple inorganic nanoparticles in the above-described particle arrangement nano-region can be confirmed by observing the particle-fixed substrate using an atomic force microscope (AFM). The width of the above-described particle arrangement nano-region and the spacing between multiple particle arrangement nano-regions can also be measured by AFM.

[0032] The particle-immobilized substrate described above includes regions other than the particle-arranged nano-regions in which inorganic nanoparticles are not arranged. Furthermore, the particle-immobilized substrate may also have regions other than the particle-arranged nano-regions (i.e., regions with a width exceeding 1 μm) in which inorganic nanoparticles are immobilized.

[0033] Preferably, the potential difference between the zeta potential of the inorganic nanoparticles and the zeta potential of the substrate surface at the location where the inorganic nanoparticles are placed is 30 mV or more, more preferably 40 mV or more, and even more preferably 50 mV or more. When the potential difference is 30 mV or more, the potential difference between the inorganic nanoparticles and the substrate surface at the location where the inorganic nanoparticles are placed is sufficiently large, allowing the inorganic nanoparticles to easily adhere to the substrate by electrostatic action, and after adhesion, they are less likely to fall off. It is also preferable that the potential difference at at least one point between pH 2 and 12 (preferably pH 4 to 10, more preferably pH 5 to 8) is within the above range.

[0034] Examples of the inorganic nanoparticles mentioned above include metal nanoparticles, semiconductor nanoparticles, and nanocarbon particles. The inorganic nanoparticles may consist of only one type or two or more types.

[0035] Examples of materials that constitute the above-mentioned metal nanoparticles and semiconductor nanoparticles include silver, aluminum, gold, platinum, palladium, copper, cobalt, chromium, indium, nickel, and gallium. Among these, silver is preferred. One or more of the above materials may be used. Specific examples of the above-mentioned metal nanoparticles and semiconductor nanoparticles include nanoparticles made from one or more of the above-mentioned materials, and nanoparticles made from compounds of the above materials (for example, GaN nanoparticles, GaAs nanoparticles, AlN nanoparticles, GaAlN nanoparticles).

[0036] The above nanocarbon particles are not particularly limited, and known or conventional nano-order carbon material (nanocarbon material) particles can be used. Examples of nanocarbon materials for the above nanocarbon particles include nanodiamond, fullerene, graphene oxide, nanographite, carbon nanotubes, carbon nanofilaments, onion-like carbon, diamond-like carbon, amorphous carbon, carbon black, carbon nanohorns, and carbon nanocoils. Among the above nanocarbon particles, nanodiamond particles are preferred.

[0037] In this specification, "inorganic nanoparticles" refers to inorganic particles whose primary particle size (average primary particle diameter) is less than 1000 nm. The average primary particle diameter of the above inorganic nanoparticles is, for example, 100 nm or less, preferably 60 nm or less, more preferably 50 nm or less, and even more preferably 30 nm or less. The lower limit of the average primary particle diameter of the above inorganic nanoparticles is, for example, 1 nm.

[0038] As the nanodiamond particles mentioned above, for example, detonation-produced nanodiamonds (i.e., nanodiamonds produced by the detonation method) or high-temperature, high-pressure-produced nanodiamonds (i.e., nanodiamonds produced by the high-temperature, high-pressure-produced method) can be used. Among these, detonation-produced nanodiamonds are preferred because they have superior dispersibility in the dispersion medium, that is, because the particle size of the primary particles is in the order of one order of magnitude nanometers.

[0039] The above-mentioned detonation-processed nanodiamonds include air-cooled detonation-processed nanodiamonds (i.e., nanodiamonds produced by the air-cooled detonation method) and water-cooled detonation-processed nanodiamonds (i.e., nanodiamonds produced by the water-cooled detonation method). Among these, air-cooled detonation-processed nanodiamonds are preferred over water-cooled detonation-processed nanodiamonds because their primary particles are smaller.

[0040] The nanodiamond particles described above are not particularly limited, and known or conventional nanodiamond particles can be used. The nanodiamond particles may be surface-modified nanodiamond particles (surface-modified nanodiamonds) or unmodified nanodiamond particles. Unmodified nanodiamond particles have hydroxyl groups (-OH) or carboxyl groups (-COOH) on their surface. Only one type of nanodiamond particle may be used, or two or more types may be used.

[0041] Examples of compounds or functional groups used to surface-modify nanodiamond particles in the above-mentioned surface-modified nanodiamonds include silane compounds, phosphonate ions or phosphonate residues, surface-modifying groups having vinyl groups at their termini, amide groups, cationic surfactants, groups containing polyglycerin chains, and groups containing polyethylene glycol chains.

[0042] The zeta potential of the inorganic nanoparticles described above may be negative or positive. It is preferable that the sign of the zeta potential is the same as that of the zeta potential on a substrate where the inorganic nanoparticles are not placed. When the zeta potential of the inorganic nanoparticles is positive, it is preferably 5mV or higher, more preferably 10mV or higher, and even more preferably 20mV or higher. When the zeta potential of the inorganic nanoparticles is negative, it is preferably -5mV or lower, more preferably -10mV or lower, and even more preferably -15mV or lower. Note that particles having many hydroxyl groups or carboxyl groups on their surface, such as unmodified nanodiamond particles, tend to have a negative zeta potential due to oxygen-based functional groups. Examples of nanodiamond particles with a positive zeta potential include those surface-terminated with hydrogen. Furthermore, it is preferable that the zeta potential at least one point within the pH range of 2 to 12 (preferably pH 4 to 10, more preferably pH 5 to 8) is within the above range.

[0043] The materials constituting the above substrate are not particularly limited, but include resins, metals, metal oxides, metal carbides, metal nitrides, and glass. Examples of resins include polyolefin resins, polyester resins, polyamide resins, polyimide resins, polycarbonate resins, phenolic resins, epoxy resins, silicon resins, fluororesins, and urethane resins. Examples of metals include Si, Au, Cu, Pt, Zn, Fe, Ta, Bi, Te, Ga, or alloys containing at least one of these metals. Examples of metal oxides include oxides of these metals. Among these, Si substrates, SiO2 substrates, SiC substrates, and GaN substrates are preferred as the substrate, from the viewpoint that the above particle-immobilized substrate can be applied to semiconductor applications.

[0044] The zeta potential of the surface of the region on the substrate where the inorganic nanoparticles are arranged may be negative or positive. It is preferable that the zeta potential has a different sign from that of the inorganic nanoparticles.

[0045] Furthermore, the zeta potential of the surface of the region of the substrate where the inorganic nanoparticles are not arranged may be negative or positive. It is preferable that the sign is the same as the zeta potential of the inorganic nanoparticles.

[0046] For the regions of the substrate in which the inorganic nanoparticles are arranged and those in which they are not arranged, the zeta potential when the surface zeta potential is positive is preferably 5 mV or higher, and more preferably 10 mV or higher. For the regions of the substrate in which the inorganic nanoparticles are arranged and those in which they are not arranged, the zeta potential when the surface zeta potential is negative is preferably -10 mV or lower, and more preferably -20 mV or lower. The above zeta potential is a value measured under the same conditions (e.g., pH) as when measuring the zeta potential of the inorganic nanoparticles.

[0047] The potential difference in the zeta potential between the inorganic nanoparticles and the surface of the region on the substrate where the inorganic nanoparticles are arranged is preferably 30 mV or more, more preferably 40 mV or more, even more preferably 50 mV or more, and particularly preferably 60 mV or more. When the potential difference is 30 mV or more, the potential difference between the inorganic nanoparticles and the region is sufficiently large, and by appropriately setting the zeta potential of the inorganic nanoparticles, it is possible to selectively and easily arrange the inorganic nanoparticles in a specific region by electrostatic action. Furthermore, once attached, they are less likely to fall off. It is preferable that the potential difference at at least one point in the pH range of 2 to 12 (preferably pH 4 to 10, more preferably pH 5 to 8) is within the above range.

[0048] The potential difference in the zeta potential between the surface of the substrate where the inorganic nanoparticles are placed and the surface where they are not placed is preferably 30 mV or more, more preferably 40 mV or more, even more preferably 50 mV or more, and particularly preferably 60 mV or more. When the potential difference is 30 mV or more, the potential difference between the two regions is sufficiently large, and by appropriately setting the zeta potential of the inorganic nanoparticles, it is possible to selectively and easily place the inorganic nanoparticles in a specific region by electrostatic action. Furthermore, once attached, they are less likely to fall off. It is also preferable that the potential difference at at least one point in the pH range of 2 to 12 (preferably pH 4 to 10, more preferably pH 5 to 8) is within the above range.

[0049] The potential difference in the zeta potential between the inorganic nanoparticles and the surface of the region of the substrate where the inorganic nanoparticles are not arranged is preferably less than 30 mV, more preferably 25 mV or less, and even more preferably 20 mV or less. When the potential difference in the zeta potential is less than 30 mV, the potential difference is small, and the inorganic nanoparticles and the region of the substrate where the inorganic nanoparticles are not arranged repel each other, making it difficult for the inorganic nanoparticles in the particle arrangement nano region to adhere to the area outside the particle arrangement nano region. It is also preferable that the zeta potential at at least one point between pH 2 and 12 (preferably pH 4 to 10, more preferably pH 5 to 8) is within the above range.

[0050] The above substrate preferably has hydroxyl groups or carboxyl groups (more preferably hydroxyl groups) on the surface of the region where the inorganic nanoparticles are not arranged. The above metal oxides tend to have hydroxyl groups on the substrate surface.

[0051] The above-described particle-immobilized substrate has inorganic nanoparticles arranged in an extremely small region with a width of 1 μm. Therefore, the above-described particle-immobilized substrate can be suitably applied to nanodevices in semiconductor fields such as thermoelectric conversion elements, solar cells, displays, memories, thin-film transistors, and LSIs. It can also be suitably applied to semiconductor devices (nanodevices) that use a core made of inorganic nanoparticles as quantum dots.

[0052] [Method for manufacturing particle-immobilized substrates] The above-mentioned particle-fixed substrate can be manufactured by a process (electrostatic deposition process) in which inorganic nanoparticles are placed in the first region of a substrate having a first region and a second region with different zeta potentials from each other by electrostatic action. In the above electrostatic deposition process, since the electrostatic action of the inorganic surface constituting the inorganic nanoparticles is utilized, the inorganic nanoparticles placed in the above electrostatic deposition process are particles in which the inorganic material constituting the inorganic nanoparticles is exposed on the surface, for example, particles whose surface is not completely covered by the resin layer.

[0053] In the above substrate, the first region is a region to which inorganic nanoparticles are attached and has a width of 1 μm or less. The region with a width of 1 μm or less becomes the particle-arranged nano region when inorganic nanoparticles are arranged thereon. Therefore, the shape, pattern, and width of the first region are appropriately set according to the particle-arranged nano region. The first region may also have a region with a width exceeding 1 μm. The second region is a region excluding the first region and is a region where inorganic nanoparticles are not arranged.

[0054] The above-mentioned substrate can be one of those exemplified and described as a substrate in the particle-immobilizing substrate mentioned above.

[0055] The potential difference between the zeta potentials of the first and second regions is preferably 30 mV or more, more preferably 40 mV or more, even more preferably 50 mV or more, and particularly preferably 60 mV or more. When the potential difference is 30 mV or more, the potential difference between the first and second regions is sufficiently large, and by appropriately setting the zeta potential of the inorganic nanoparticles, it is possible to selectively and easily place the inorganic nanoparticles in the first region by electrostatic action. Furthermore, once attached, they are less likely to fall off. It is preferable that the potential difference at at least one point in the pH range of 2 to 12 (preferably pH 4 to 10, more preferably pH 5 to 8) is within the above range. When the potential difference is within the above range at at least one point where the pH is within the above range, the inorganic nanoparticles can be attached to the first region by electrostatic action at that pH.

[0056] The first and second regions described above may have one zeta potential that is positive and the other that is negative, or both zeta potentials that are positive, or both zeta potentials that are negative. In particular, it is preferable that one zeta potential is positive and the other that is negative. In this case, inorganic nanoparticles having a zeta potential with a sign different from that of the first region can be easily placed in the first region by electrostatic action. It is especially preferable that the zeta potential of the first region is positive and the zeta potential of the second region is negative.

[0057] The potential difference between the zeta potential of the first region and the zeta potential of the inorganic nanoparticles is preferably 30 mV or more, more preferably 40 mV or more, and even more preferably 50 mV or more. When the potential difference is 30 mV or more, the potential difference between the inorganic nanoparticles and the first region is sufficiently large, allowing the inorganic nanoparticles to easily adhere to the first region by electrostatic action, and after adhesion, they are less likely to fall off. It is also preferable that the potential difference at at least one point between pH 2 and 12 (preferably pH 4 to 10, more preferably pH 5 to 8) is within the above range. When the potential difference is within the above range at at least one point where the pH is within the above range, the inorganic nanoparticles can adhere to the first region by electrostatic action at that pH.

[0058] The potential difference between the zeta potential of the second region and the zeta potential of the inorganic nanoparticles is preferably less than 30 mV, more preferably 25 mV or less, and even more preferably 20 mV or less. When the potential difference of the zeta potential is less than 30 mV, the potential difference is small, and the inorganic nanoparticles and the second region repel each other, making it difficult for the inorganic nanoparticles to adhere to the second region. It is also preferable that the zeta potential at at least one point between pH 2 and 12 (preferably pH 4 to 10, more preferably pH 5 to 8) is within the above range.

[0059] Of the first and second regions described above, the zeta potential of the region where the zeta potential is positive is preferably 5 mV or higher, and more preferably 10 mV or higher. The zeta potential is measured under the same conditions (e.g., pH) as when measuring the zeta potential of the inorganic nanoparticles.

[0060] The region with a positive zeta potential preferably has a cationic group on its surface, more preferably an amino group. Preferably, there is one or more cationic groups at a single bonding position (within a single cationic group-containing group) in the region with a positive zeta potential, more preferably 2 to 4, and even more preferably 2. The amino group may be a primary, secondary, or tertiary amino group, but it is preferable to have a primary amino group (particularly primary and secondary amino groups). The amino group forms an ammonium ion during the electrostatic deposition process, causing the zeta potential of that region to become positive.

[0061] Of the first and second regions described above, the zeta potential of the region with a negative zeta potential is preferably -10 mV or less, and more preferably -20 mV or less. The region with a negative zeta potential preferably contains hydroxyl groups or carboxyl groups (more preferably hydroxyl groups). The above zeta potential is a value measured under the same conditions (e.g., pH) as when measuring the zeta potential of the inorganic nanoparticles.

[0062] (Electrostatic deposition process) In the electrostatic deposition process described above, inorganic nanoparticles are arranged by electrostatic action in the first region of a substrate having a first region and a second region with different zeta potentials. Specifically, for example, the substrate is immersed in an aqueous dispersion of inorganic nanoparticles. In this case, if the potential difference between the zeta potential of the surface of the inorganic nanoparticles and the zeta potential of the first region is large, or if the signs of their zeta potentials are different (i.e., one zeta potential is negative and the other is positive), the inorganic nanoparticles adhere to the first region by electrostatic action.

[0063] The zeta potential of the surface of the inorganic nanoparticles can be adjusted by known or conventional methods. If the inorganic nanoparticles are nanodiamond particles, for example, the zeta potential of the surface of the nanodiamond particles can be adjusted by appropriately selecting compounds or functional groups to modify the surface of the nanodiamond particles. The preferred range of the zeta potential of the inorganic nanoparticles used in the electrostatic deposition process is as described above.

[0064] The immersion temperature is, for example, 0 to 100°C (preferably 10 to 40°C), and the immersion time is, for example, 10 seconds to 1 hour (preferably 20 seconds to 10 minutes). After immersion, the substrate surface may be thoroughly washed with pure water, and then any remaining water on the surface may be removed by air blowing or the like.

[0065] The above manufacturing method may include other steps besides the electrostatic deposition step. These other steps include a step performed before the electrostatic deposition step to form two regions A and B on the substrate surface, each with a different zeta potential (region AB formation step). Here, one of regions A and B can be designated as the first region and the other as the second region.

[0066] (Step (i)) The above-mentioned region AB formation process includes (i) a step of reacting a reactive functional group present on the substrate with a compound that is reactive with the reactive functional group to form a region A having a zeta potential different from the zeta potential of the substrate surface before the reaction (region A formation step), and a step of irradiating a part of region A with an electron beam to cut at least a part of the group formed by the above reaction to form a region B having a zeta potential different from the zeta potential of region A (region B formation step).

[0067] Step (i) described above will be explained in detail with reference to Figure 3. In the region A formation step, a compound that is reactive with the reactive functional groups present on the substrate 2 is applied to the substrate 2 and reacted with the reactive functional groups to form region A(4). The application may be carried out using a known or conventional coater, or by immersing the substrate 2 in the compound. Alternatively, the application of the compound may be carried out using a solution or dispersion containing a solvent that can dissolve or disperse the compound, such as an organic solvent. Furthermore, in the region A formation step, region A(4) may be formed over the entire surface of the substrate 2 or only on a part of it.

[0068] In the region A formation stage, for example, a Si substrate can be used as substrate 2, and an amino group-containing silane coupling agent can be used as the compound. Normally, an SiO2 layer exists on the surface of the Si substrate. In this case, the hydroxyl groups (silanol groups) on the surface of the SiO2 layer react with the amino group-containing silane coupling agent to form siloxane bonds by a condensation reaction, thereby forming groups having amino groups on the surface of the Si substrate and forming region A. Examples of the amino group-containing silane coupling agent include 3-aminopropyltriethoxysilane and 3-(2-aminoethylamino)propyltrimethoxysilane.

[0069] The above condensation reaction is carried out by immersing the substrate in a solvent in which the silane coupling agent can dissolve or disperse, such as an organic solvent, adding the silane coupling agent, and stirring under an inert gas atmosphere. The temperature in the above condensation reaction is, for example, 10 to 90°C, and the time is, for example, 3 to 30 hours. Furthermore, the above condensation reaction is preferably carried out in the pH range of 2 to 12, more preferably 4 to 10, and even more preferably 5 to 8. After the above condensation reaction, the substrate surface may be cleaned as needed. Cleaning is preferably performed by cleaning with the solvent used in the reaction, followed by cleaning with ethanol and then with pure water. After that, if necessary, any water remaining on the substrate surface may be removed by air blowing or the like, and then dried in a drying oven. In this way, a region A having amino groups can be formed on the surface.

[0070] In the region B formation stage, for example, as shown in Figure 3, electron beam irradiation 5 is performed on a portion of region A(4) formed in the region A formation stage to decompose the groups formed by the above reaction (for example, groups having amino groups), returning the substrate 2 surface to the state before region A(4) was formed and forming region B(6). That is, the zeta potential of region B(6) is the same as the zeta potential of the substrate 2 surface before region A(4) was formed.

[0071] As shown in Figure 3, the substrate surface may be returned to its state before region A was formed by electron beam irradiation, or region B may be formed having a zeta potential different from that of region A by cleaving or decomposing at least some of the bonds of the groups formed by the above reaction.

[0072] Electron beam irradiation of a portion of region A can be performed using an EB lithography system according to a pre-designed pattern. That is, the shapes of the first and second regions can be formed according to the pattern shape designed using the EB lithography system.

[0073] As described above, step (i) can be used to fabricate a substrate having two regions A and B on its surface that have different zeta potentials from each other.

[0074] If region B formed during the region B formation stage has a region with a width of 1 μm or less, region B can be designated as the first region. If the remaining region A during the region B formation stage has a region with a width of 1 μm or less, region A can be designated as the first region.

[0075] For example, when a Si substrate is used as substrate 2 and an amino group-containing silane coupling agent is used as the compound, region A, which has amino groups on its surface, tends to have a positive zeta potential at pH 7 or below. Region B, formed by electron beam irradiation, has a zeta potential derived from oxygen-based functional groups, similar to the Si substrate surface before region A was formed, and tends to be negative. Therefore, when region A is designated as the first region, inorganic nanoparticles with a negative zeta potential are used to fix inorganic nanoparticles to region A in the electrostatic deposition process. On the other hand, when region B is designated as the first region, inorganic nanoparticles with a positive zeta potential are used to fix inorganic nanoparticles to region B in the electrostatic deposition process.

[0076] (Step (ii)) Furthermore, the above-mentioned region AB formation process may also include (ii) a step of forming a resist film on the substrate surface, then dissolving a portion of the resist film by electron beam irradiation and development to create holes in the resist film and expose the substrate (resist mask formation step), a step of reacting reactive functional groups present on the exposed substrate with a compound that is reactive with said reactive functional groups to form region A having a zeta potential different from the zeta potential of the substrate surface before the reaction (region A formation step), and a step of removing the resist film on the substrate surface to expose the substrate surface and form region B (resist removal step).

[0077] Step (ii) described above will be explained in detail with reference to Figure 4. In the resist mask formation step, a resist film 7 is formed on the substrate 2 by a known or conventional method. Next, a portion of the resist film 7 is irradiated with an electron beam 5, and the resist film in the electron beam irradiated area 7' is dissolved by etching or the like during the subsequent development process, exposing the substrate surface 8 and forming a resist mask. In Figure 4, instead of the electron beam irradiated area 7', the resist film in the unirradiated area may be dissolved by etching or the like to expose the substrate surface 8.

[0078] Then, in the region A formation stage, the compound is applied to the exposed substrate surface 8. The application of the compound is preferably carried out in the gas phase (by vapor deposition) to prevent the resist film 7 from dissolving during application. Specifically, the substrate 2 with the resist film 7 and an open container containing the compound are placed in a sealed container, and the sealed container is closed and left to stand. During this standing period, the compound volatilizes within the sealed container, and the volatilized compound adheres to the substrate surface 8. Alternatively, the application of the compound may be carried out using a solution or dispersion containing a solvent capable of dissolving or dispersing the compound, such as an organic solvent.

[0079] When a Si substrate is used as substrate 2 and an amino group-containing silane coupling agent is used as the compound, the condensation reaction proceeds in the same manner as the region A formation step in step (i), and groups having amino groups are formed on the substrate surface 8, forming region A(4). In addition, during the region A formation step, region A(4) may be formed only on the substrate surface 8, or it may also be formed on the resist film 7.

[0080] Next, in the resist removal step, the remaining resist film (resist mask) 7 is removed to expose the substrate surface, and the exposed area is formed as area B(6). The resist mask can be removed by known or conventional methods, for example, by immersion in an organic solvent (developer) that dissolves the resist film.

[0081] As described above, step (ii) makes it possible to fabricate a substrate having two regions A and B on its surface that have different zeta potentials from each other.

[0082] If the region of the substrate surface exposed during the resist mask formation stage has a width of 1 μm or less, the region A formed thereafter can be designated as the first region. If the region of the remaining resist film during the resist mask formation stage has a width of 1 μm or less, the substrate surface (region B) exposed during the resist removal stage can be designated as the first region.

[0083] For example, when a Si substrate is used as substrate 2 and an amino group-containing silane coupling agent is used as the compound, region A, which has amino groups on its surface, tends to have a positive zeta potential at pH 7 or below. Region B, formed by removing the resist mask, has a zeta potential derived from oxygen-based functional groups, similar to the Si substrate surface before region A was formed, and tends to be negative. Therefore, when region A is designated as the first region, inorganic nanoparticles with a negative zeta potential are used to fix inorganic nanoparticles to region A in the electrostatic deposition process. On the other hand, when region B is designated as the first region, inorganic nanoparticles with a positive zeta potential are used to fix inorganic nanoparticles to region B in the electrostatic deposition process.

[0084] In describing the above manufacturing method, an example was given in which a Si substrate was used as the substrate and an amino group-containing silane coupling agent was used as the compound that reacts with the reactive functional groups on the substrate surface. However, the above manufacturing method is not limited to this example. That is, by using a substrate having reactive functional groups on its surface in combination with a compound having functional groups that react with said reactive functional groups and have a different zeta potential from the substrate surface, the particle-immobilized substrate can be manufactured in the same manner as in the above example using known or conventional techniques.

[0085] [Manufacturing method for diamond film-fixed substrates] Using nanodiamond particles as the inorganic nanoparticles, a particle-fixed substrate can be manufactured by growing the nanodiamond particles using the nanodiamond particles as a seed by chemical vapor deposition (CVD) to form a diamond film on the substrate (CVD process).

[0086] The above CVD method can be carried out by known or conventional methods. For example, the particle-fixed substrate is placed in a gas phase containing a carbon source such as methane and hydrogen, and a plasma of a mixed gas of hydrogen and methane is generated in the gas phase. This generates atomic hydrogen and carbon radicals, which grow nanodiamond particles on the particle-fixed substrate as seed crystals, and a diamond film is formed when these particles bond to each other (coalescence).

[0087] The various conditions in the above CVD process, such as temperature, pressure, gas supply amount, and gas concentration, are not particularly limited and can be adjusted as appropriate. The time spent in the CVD process is adjusted as appropriate depending on the thickness and growth of the resulting diamond film, the width of the pattern (width of the formed nano-region described later), and the spacing. The methane concentration in the gas phase during the CVD process (concentration relative to the total of methane and hydrogen) is, for example, 0.1 to 10 volume%, preferably 1 to 5 volume%. The hydrogen concentration in the gas phase during the CVD process (concentration relative to the total of methane and hydrogen) is, for example, 90 to 99.9 volume%, preferably 95 to 99 volume%. The temperature is preferably 200 to 1500°C, more preferably 500 to 1200°C. The diamond growth time in the CVD process is, for example, 1 to 30 minutes, preferably 5 to 25 minutes, more preferably 10 to 20 minutes.

[0088] The diamond film-fixed substrate obtained by the above manufacturing method comprises the substrate and a diamond film formed on the substrate. The diamond film is formed from nanodiamond particles fixed as inorganic nanoparticles on the particle-fixed substrate, either grown (grown diamond particles) or grown and bonded together. Examples of the diamond film include a film formed from multiple grown diamond particles, where each diamond particle has grown and is not bonded to adjacent particles, and a film in which each diamond particle has grown and bonded to adjacent diamond particles. The diamond film may have voids or cavities originating from the gaps between nanodiamond particles on the particle-fixed substrate.

[0089] The above-mentioned diamond film-fixed substrate preferably has a region (film-forming nano region) on which the diamond film is formed with a width of 1 μm or less. Such a diamond film can be fabricated by growing nanodiamond particles arranged in the above-mentioned particle-arrangement nano region. The above-mentioned diamond film may also be formed outside the region on the substrate with a width of 1 μm or less.

[0090] Figure 5 shows an enlarged schematic diagram of one embodiment of the diamond film-fixed substrate having the above-mentioned film-forming nanoregion. The diamond film-fixed substrate 10 is fabricated by growing nanodiamond particles 3 on the particle-fixed substrate 1 shown in Figure 1 by the CVD method. The diamond film-fixed substrate 10 shown in Figure 5 includes a substrate 2 and a plurality of diamond films 3'. In the diamond film-fixed substrate 10, one diamond film 3' is located within a region (film-forming nanoregion) on the substrate 2 that has a width D1 of 1 μm or less and extends in the lateral direction (a direction perpendicular to the width D1). Multiple regions with a width D1 extending in the lateral direction are arranged vertically at intervals of D2, forming a stripe pattern.

[0091] Figure 6 shows an enlarged schematic diagram of another embodiment of the diamond film-fixed substrate having the above-mentioned film-forming nanoregion. The diamond film-fixed substrate 10 is manufactured by growing nanodiamond particles 3 on the particle-fixed substrate 1 shown in Figure 2 by the CVD method. The diamond film-fixed substrate 10 shown in Figure 6 includes a substrate 2 and a diamond film 3'. The diamond film 3' is a film formed from multiple grown diamond particles, where the nanodiamond particles 3 on the particle-fixed substrate shown in Figure 2 have grown to the extent that the individual nanodiamond particles 3 do not bond with each other. In the diamond film-fixed substrate 10, the diamond film 3' is arranged on the substrate 2 within a region (film-forming nanoregion) that has a width D1 of 1 μm or less and extends in the lateral direction (a direction perpendicular to the width D1). Multiple regions with a width D1 extending in the lateral direction are arranged vertically at intervals of D2, forming a stripe pattern.

[0092] Furthermore, the diamond film-fixed substrate may have, for example, regions with a width of 1 μm or less on the substrate where the diamond film is not formed (substrate exposed nano regions), as shown in Figures 6 and 14. The substrate exposed nano regions may also exist within the film-forming nano regions. Such a diamond film-fixed substrate can be fabricated by growing nanodiamond particles arranged in the particle-arranged nano regions until the substrate exposed nano regions remain, so that the gaps between the nanodiamond particles are not completely filled. Such a diamond film-fixed substrate is fabricated by growing nanodiamond particles 3 in the particle-fixed substrate 1 shown in Figure 2 using the CVD method.

[0093] The above-mentioned film-forming nanoregions include shapes exemplified and described as particle-arranged nanoregions. Furthermore, the concept of "width" in the above-mentioned film-forming nanoregions is the same as that of "width" in the particle-arranged nanoregions. There may be only one of the above-mentioned film-forming nanoregions on the substrate, or there may be multiple identical or different shapes. Furthermore, the above-mentioned film-forming nanoregions may be arranged regularly (arranged) or irregularly, but a regular arrangement is preferred. Patterns that can be represented by a regular arrangement include stripe patterns, dot patterns, checkered patterns, grid patterns, houndstooth patterns, and mesh patterns. The shape of the dots in a dot pattern is not particularly limited and includes shapes such as +, circles, and polygons.

[0094] The spacing between the multiple particle arrangement regions in the regularly arranged shapes such as the stripe pattern or dot pattern described above (for example, D2 in Figures 5-6) is not particularly limited, but is preferably 0.1 to 1.5 times the width length, and more preferably 0.5 to 1.0 times.

[0095] Since the above-mentioned diamond film is formed by the growth of nanodiamond particles, the arithmetic mean roughness Ra of the film surface (e.g., 3'a in Figures 5-6) is preferably 6 nm or more (e.g., 6-20 nm), and more preferably 7 nm or more (e.g., 7-15 nm). Furthermore, the root mean square height Rq of the above-mentioned diamond film surface (e.g., 3'a in Figures 5-6) is preferably 8 nm or more (e.g., 8-30 nm), and more preferably 10 nm or more (e.g., 10-20 nm). In conventional methods, a diamond film formation fixed substrate on which a flat diamond film is formed is used, the surface of the diamond film is polished to make it smooth, and then a portion of the diamond film and substrate is removed by subsequent etching, making it possible to leave the diamond film within a region of 1 μm or less in width on the substrate. However, in such conventional methods, smoothing the surface of the diamond film is essential for resist mask pattern formation and uniform etching, so the roughness of the diamond film surface after etching is generally low.

[0096] The thickness of the diamond film (the distance between the substrate surface and the highest point of the diamond film surface) is preferably 10 to 200 nm, and more preferably 30 to 100 nm.

[0097] Since the above-mentioned diamond film-fixed substrate is obtained by growing nanodiamond particles on the above-mentioned particle-fixed substrate, the diamond film on the above-mentioned diamond film-fixed substrate is formed while maintaining the shape of the nanodiamond particles. For this reason, the above-mentioned diamond film-fixed substrate can be used in mechanical switching elements and oscillators such as MEMS and NEMS. Furthermore, when the above-mentioned diamond film is fabricated by the CVD method under high-temperature heating conditions, the substrate and the above-mentioned diamond film react to form a bond at least partially, resulting in excellent adhesion.

[0098] [Diamond manufacturing method] By removing the substrate from the diamond film-fixed substrate on which the diamond film is fixed, diamonds derived from the nanodiamond film can be produced.

[0099] The diamond derived from the above nanodiamond film is the diamond obtained when the diamond film is peeled off from the substrate, and is either a standalone solid of the diamond film or diamond particles constituting the diamond film. Specifically, if the diamond film is formed from individual growing diamond particles, the resulting diamond is the growing diamond particle. If the diamond film is formed when multiple diamond particles bond together through growth to form a single film-like diamond, the resulting diamond is the film-like diamond. The film-like diamond may have voids or cavities derived from the gaps between the nanodiamond particles in the particle-fixed substrate.

[0100] The method for removing the above-mentioned substrate can be a known or conventional method, such as a method of physically peeling the substrate off the diamond film-fixed substrate or a method of chemically removing the substrate.

[0101] According to the above-described method for manufacturing diamond, a geometrically shaped diamond film formed on the diamond film-fixing substrate can be obtained as a single, self-supporting solid diamond, such as a film-like diamond (rod-shaped diamond). Furthermore, as grown diamond particles, self-supporting solid particles of particulate diamond slightly larger than the seed crystal nanodiamond particles can be obtained individually. In addition, if the self-supporting solid diamond is on the nanometer scale, it can be dispersed in a solvent to produce a nanodiamond dispersion composition in which diamond is dispersed in a solvent. This nanodiamond dispersion composition is expected to be used in bio-applications such as biosensing and bioimaging.

[0102] Each embodiment disclosed herein can be combined with any other features disclosed herein. Each configuration and combination thereof in each embodiment is an example, and additions, omissions, substitutions, and other modifications are permitted as appropriate, without departing from the spirit of this disclosure. Furthermore, each invention relating to this disclosure is not limited by the embodiments or the following examples, but is limited solely by the claims. [Examples]

[0103] An embodiment of this disclosure will be described in more detail below based on examples.

[0104] Example 1 (Pretreatment of Si substrate) A 500 mL beaker was prepared, 200 mL of deionized water (pure water) was poured in, and 100 mL of 12% by mass ammonia water was added. The beaker was then immersed in an oil bath and heated to approximately 96°C. Subsequently, the oil bath temperature was set to 80°C, and 40 mL of 30% by mass hydrogen peroxide water was added to the beaker. This resulted in an RCA (SC-1) cleaning solution at 75-80°C. Meanwhile, a commercially available semiconductor Si wafer (4-inch diameter, Si(100), p-type, single-sided polished) was cut (cleaved) into a 1.5 cm x 1.5 cm square using a wafer cutter (diamond scriber) to prepare a Si substrate. The Si substrate was quickly placed in the cleaning solution before the decomposition of the hydrogen peroxide water progressed, a watch glass was placed over the opening of the beaker, and the oil bath temperature was raised to 75-80°C and maintained at that temperature for 30 minutes. This cleaning process is called SC-1 cleaning, a type of RCA cleaning which is a common cleaning method for Si substrates. It has the effect of dissolving and removing organic matter from the Si substrate surface and peeling off insoluble particles. After 30 minutes, the oil bath power was turned off and the system was allowed to cool to below 30°C. After cooling, the Si substrate was thoroughly cleaned with running pure water without removing it, taking care to prevent the substrate from coming into contact with air. After cleaning, the polished surface of the substrate was dried with compressed air and stored in a sealed container to prevent dust from the air from adhering to it.

[0105] (Amino modification of Si substrates using an aminosilane coupling agent in a liquid-phase reaction system) 20 mL of toluene was placed in a three-necked flask, and the Si substrate that had undergone the above pretreatment was placed in the toluene solvent. Then, approximately 0.1 mL of aminosilane coupling agent (N-(2-aminoethyl)-3-aminopropyltrimethoxysilane) was added to the flask using a syringe. The flask was heated in an oil bath at 70°C for 12 hours while aeration with nitrogen was performed to carry out the reaction. After the reaction, approximately 10 mL of toluene was added to the flask, and the Si substrate was washed. The washing with toluene was repeated 2-3 times, then 10 mL of ethanol was added, and the washing was repeated 2-3 times. After washing, the Si substrate was removed and rinsed three times with pure water. After washing, the substrate was blown with air to remove moisture, placed in a petri dish, and baked in a drying oven at 110°C. In this way, the entire surface of the Si substrate was subjected to silane coupling treatment, and a region in which N-(2-aminoethyl)-3-aminopropylsilyl groups were introduced (amino-modified) was formed over the entire surface. The processed substrate was then used for the next patterning process.

[0106] (Patterning of amino-modified Si substrates by electron beam lithography) The surface of an amino-modified Si substrate was irradiated with an electron beam (EB) using an EB lithography apparatus, following pre-designed patterns. Specifically, EB irradiation was performed on nine different design patterns shown in Table 1. Only the amino groups in the EB-irradiated areas were decomposed, exposing the original Si substrate surface, while the amino groups remained in the areas that were not irradiated. As a result, at pH 6, it was possible to pattern regions with a negative zeta potential (approximately -40mV) originating from oxygen-based functional groups on the unmodified Si substrate surface and regions with a positive zeta potential (approximately 30mV) originating from amino groups. The method for measuring the zeta potential is described later.

[0107] [Table 1]

[0108] In the table, "L&S" (Line and space) indicates a stripe shape, where L is the width of the electron beam-irradiated area and S is the width of the unirradiated area. Also, "HOLE(SQ)" indicates a shape with a square-shaped hole, where Λ is the width of the electron beam-irradiated area and Φ is the width of the unirradiated area.

[0109] (Selective coating of nanodiamonds (electrostatic adsorption)) Nanodiamonds were coated onto the surface of a Si substrate using a zeta-nanodiamond aqueous dispersion (product name "DINNOVARE", manufactured by Daicel Corporation, zeta potential at pH 6: approximately -27mV). Specifically, 10 mL of the above nanodiamond aqueous dispersion was taken into a plastic container, and the Si substrate, which had been patterned as described above, was immersed in the nanodiamond aqueous dispersion. After about 1 minute, the Si substrate was removed, and the substrate surface was thoroughly washed with pure water. The washed Si substrate surface was blown with air to remove any remaining water, and it was stored in a sealed container. The surface morphology of the obtained Si substrate (nanodiamond particle-immobilized substrate) was analyzed by atomic force microscopy (AFM) as follows.

[0110] (Evaluation of nanodiamond deposition state on Si substrate using AFM) The surface morphology of a substrate immobilized with nanodiamond particles was analyzed using an AFM (Anatomical Microscope Function) instrument ("Dimension Icon," manufactured by Bruker). The analysis conditions were as follows: Probe: ScanAsyst-Air Mode: QNM in Air (Standard) Scan Rate: 0.5Hz

[0111] Analysis of the L&S patterns (X:1,Y:1), (X:1,Y:2), (X:1,Y:3), and (X:2,Y:1) shown in Table 1 above using an AFM instrument revealed areas where nanodiamond particles were adsorbed and areas where they were not. In the patterning of (X:1,Y:3), it was observed that nanodiamonds were adsorbed in an area with a width of 500 nm and not in an area with a width of 200 nm. As a representative example, the AFM image obtained from the patterning of (X:1,Y:3) is shown in Figure 7.

[0112] Example 2 (Formation of resist patterns by electron beam lithography) A resist resin (product name "ZEP520A", manufactured by Nippon Zeon Co., Ltd.) was uniformly applied to the surface of a Si substrate, which had been pretreated in the same manner as in Example 1, using a spin coater. The resist resin formed on the Si substrate was irradiated with EB using an EB lithography apparatus according to a pre-designed pattern. Specifically, EB irradiation was performed for nine different design patterns shown in Table 2. Subsequently, the substrate was immersed in 100 mL of ZEP520A resist developer (anisole solvent) placed in a 200 mL beaker to form a resist mask pattern according to the design pattern.

[0113] [Table 2]

[0114] (Amino modification of Si substrates using a gas-phase reaction system aminosilane coupling agent) A 400 mL sealed glass container was prepared, and a Si substrate with a resist mask pattern formed on it was placed face up inside. A screw-cap tube containing approximately 10 mL of 3-aminopropyltriethoxysilane (APTES) was placed next to the Si substrate in the sealed glass container, without its lid. The lid of the sealed glass container was then closed and left for 20 hours. During this time, the volatile APTES reacted with the silanol groups in the areas of the Si substrate where the resist mask was not formed, selectively modifying those areas with amino compounds. After 20 hours, the Si substrate was removed and immersed in toluene for 10 minutes to completely remove the resist mask pattern. This allowed for the patterning of regions with a negative zeta potential (approximately -40 mV) originating from oxygen-based functional groups on the surface of the unmodified Si substrate at pH 6, and regions with a positive zeta potential (approximately 30 mV) originating from amino groups. The method for measuring the zeta potential is described later.

[0115] (Selective coating of nanodiamonds (electrostatic adsorption)) Nanodiamonds were applied to the surface of the Si substrate patterned as described above, in the same manner as in Example 1. The surface morphology of the obtained Si substrate (nanodiamond particle-immobilized substrate) was analyzed by atomic force microscopy (AFM) as follows. The conditions for AFM analysis were the same as in Example 1.

[0116] Analysis using an AFM instrument revealed areas where nanodiamond particles were adsorbed and areas where they were not, for all nine design patterns shown in Table 2. As a representative example, Figure 8 shows the AFM image obtained from the finest pattern, (X:3, Y:3).

[0117] <Method for measuring zeta potential> For zeta potential measurement, the "Zetasizer Nano ZS" (manufactured by Malvern Panalytical) was used. Zeta potential cannot be measured on substrate-like materials, only on particles dispersed in a solvent. Therefore, for the zeta potential of nanodiamond particles, the used nanodiamond particle aqueous dispersion was directly placed in the apparatus and measured. On the other hand, the measurement of the zeta potential of the pre-treated Si substrate surface was substituted by measuring the zeta potential of a dispersion obtained by dispersing silicon nanoparticles in pure water. Furthermore, the measurement of the zeta potential of an amino-modified Si substrate was substituted by measuring the zeta potential of a dispersion obtained by dispersing silicon nanoparticles, which had undergone the same amino-modification treatment as the substrate, in pure water. The measurement principle involves measuring the electrophoretic speed of nanoparticles dispersed in a solvent within a certain electric field strength using the laser Doppler effect with a 633 nm laser, and converting that speed to the zeta potential using Henry's equation. The measurement conditions involved calculating the average of 300 scan results in a 173° backscatter configuration. The zeta potential can be calculated independently of the particle concentration in the liquid if it is between 0.01% and 1% by mass. In this example, measurements were performed with a nanodiamond particle concentration of 1% by mass and a silicon nanoparticle concentration of 0.1% by mass.

[0118] Example 3 (Fabrication of nanodiamond particle-immobilized substrates) Nanodiamond particle-immobilized substrates were fabricated in the same manner as in Example 2. Four types of patterns were fabricated: "L&S" (200 / 200 (L / S)), "L&S" (150 / 150 (L / S)), "L&S" (100 / 100 (L / S)), and "HOLE(SQ)" (200 / 200 (Λ / φ)).

[0119] (Fabrication of diamond film-fixed substrates) The nanodiamond particle-immobilized substrate prepared as described above was subjected to a CVD process to form a diamond film. A microwave plasma CVD apparatus (product name "SDS series: SDS5200S", manufactured by Cornes Technology Co., Ltd.) was used for the CVD process. Specifically, the nanodiamond particle-immobilized substrate was placed in the center of a Mo-based disc in the CVD apparatus, and a boron nitride ring was placed around it. Then, the vacuum chamber was subjected to a 3 × 10⁻¹⁶ process. -6 The chamber was evacuated to below Torr. H2 and CH4 were introduced in a ratio of 97:3 to raise the pressure to 10 Torr, and microwave oscillation was started to generate plasma. The pressure inside the apparatus was kept constant by continuously evacuating with a rotary pump while introducing gas at a total flow rate of 300 sccm (H2: 291 sccm, CH4: 9 sccm). Immediately after starting microwave oscillation, the pressure was quickly increased to 60 Torr to transition to CVD conditions suitable for diamond growth. The substrate temperature was measured on the Si substrate surface using an optical pyrometer. The diamond growth time was 10 min. The diamond growth conditions are shown below. After growth was complete, the gas was evacuated using a rotary pump and a turbomolecular pump, and after natural cooling for about 30 minutes, the sample was removed by opening it to the atmosphere.

[0120] <Conditions for diamond growth using microwave plasma CVD> • Pre-exhaust pressure: 1.0 × 10 -6 Less than Torr • CH4 concentration {CH4 / (CH4+H2)}: 3% by volume • Discharge pressure: 60 Torr • Gas flow rate: 300 sccm • Microwave power: 1.2kW • Substrate temperature: Approximately 1030°C ·Growth time: 10min

[0121] The surface morphology of the obtained Si substrate (diamond film-fixed substrate) was analyzed using a scanning electron microscope (SEM) (model "SU5000", manufactured by Hitachi High-Tech Corporation). The acceleration voltage was set to 3.0 kV.

[0122] Table 3 shows the pattern types and drawing numbers of the SEM images for the substrates that underwent SEM analysis. The patterns shown in Table 3 are the design patterns on the nanodiamond particle-immobilized substrates before the CVD process. For all four design patterns shown in Table 3, SEM analysis revealed areas where a diamond film formed by the growth of nanodiamond particles was present and areas where it was not. Furthermore, the surface roughness of the diamond film for No. 1 was measured at two locations using an atomic force microscope (AFM), and the arithmetic mean roughness Ra was 8.70 nm and 11.2 nm, and the root mean square height Rq was 11.1 nm and 14.4 nm (measurement locations are shown in Figure 13). In addition, a cross-sectional plot of the diamond film height was measured for No. 1. The measurement locations and results are shown in Figure 14.

[0123] [Table 3]

[0124] The following describes variations of the invention relating to this disclosure. [Note 1] The system comprises a substrate and a plurality of inorganic nanoparticles arranged on the substrate, A particle-immobilized substrate in which the plurality of inorganic nanoparticles are arranged in contact with each other within an area on the substrate with a width of 1 μm or less. [Note 2] The particle-immobilized substrate according to Note 1, wherein the potential difference between the zeta potential of the inorganic nanoparticles and the zeta potential of the substrate surface at the position where the inorganic nanoparticles are arranged is 30 mV or more (or 40 mV or more, 50 mV or more). [Note 3] The particle-immobilized substrate according to Note 1 or 2, wherein one zeta potential of the inorganic nanoparticles and the substrate surface at the positions where the inorganic nanoparticles are arranged is positive and the other zeta potential is negative. [Note 4] The system comprises a substrate and inorganic nanoparticles disposed on the substrate, A particle-immobilized substrate in which the potential difference between the zeta potential of the inorganic nanoparticles and the zeta potential of the substrate surface at the location where the inorganic nanoparticles are arranged is 30 mV or more (or 40 mV or more, 50 mV or more). [Note 5] The particle-immobilizing substrate according to Note 4, wherein one zeta potential of the inorganic nanoparticles and the substrate surface at the positions where the inorganic nanoparticles are arranged is positive and the other zeta potential is negative. [Note 6] The system comprises a substrate and inorganic nanoparticles disposed on the substrate, A particle-immobilized substrate wherein the inorganic nanoparticles and the substrate surface at the positions where the inorganic nanoparticles are arranged have one zeta potential that is positive and the other zeta potential that is negative. [Note 7] A particle-immobilized substrate according to any one of Notes 1 to 6, wherein a plurality of regions with a width of 1 μm or less (or 600 nm or less, 300 nm or less, or 150 nm or less) are regularly arranged on the substrate, and the inorganic nanoparticles are arranged within each of the plurality of regions with a width of 1 μm or less (or 600 nm or less, 300 nm or less, or 150 nm or less). [Note 8] The particle-immobilized substrate according to any one of Notes 1 to 7, wherein the nanoparticles include one or more selected from the group consisting of metal nanoparticles, semiconductor nanoparticles, and nanocarbon particles (preferably nanocarbon particles, more preferably nanodiamond particles).

[0125] [Note 9] A particle-immobilized substrate according to any one of Notes 1 to 8, wherein the sign of the zeta potential of the inorganic nanoparticles is different from the sign of the zeta potential of the surface region of the substrate on which the inorganic nanoparticles are arranged. [Note 10] The particle-immobilized substrate according to any one of Notes 1 to 9, wherein the sign of the inorganic nanoparticles and the sign of the zeta potential of the surface region of the substrate where the inorganic nanoparticles are not arranged are the same. [Note 11] The particle immobilization substrate according to any one of Notes 1 to 10, wherein the zeta potential of the inorganic nanoparticles is negative (preferably a zeta potential of -5mV or less, -10mV or less, or -15mV or less). [Note 12] The particle-immobilized substrate according to Note 11, wherein the zeta potential in the region of the substrate where the inorganic nanoparticles are arranged is positive (preferably 5 mV or more, more preferably 10 mV or more). [Note 13] The particle-immobilized substrate according to Note 11 or 12, wherein the zeta potential in the region of the substrate where the inorganic nanoparticles are not arranged is negative (preferably -10 mV or less, more preferably -20 mV or less). [Note 14] The particle immobilization substrate according to any one of Notes 1 to 10, wherein the zeta potential of the inorganic nanoparticles is positive (preferably a zeta potential of 5 mV or more, 10 mV or more, or 20 mV or more). [Note 15] The particle-immobilized substrate according to Note 14, wherein the zeta potential in the region of the substrate where the inorganic nanoparticles are arranged is negative (preferably -10 mV or less, more preferably -20 mV or less). [Note 16] The particle-immobilized substrate according to Note 14 or 15, wherein the zeta potential in the region of the substrate where the inorganic nanoparticles are not arranged is positive (preferably 5 mV or more, more preferably 10 mV or more). [Note 17] The particle-immobilized substrate according to any one of Notes 1 to 16, wherein the potential difference of the zeta potential between the inorganic nanoparticles and the surface of the region of the substrate on which the inorganic nanoparticles are arranged is 30 mV or more (or 40 mV or more, 50 mV or more, or 60 mV or more). [Note 18] The particle-immobilized substrate described in any one of Notes 1 to 17, wherein the potential difference of the zeta potential between the region of the substrate in which the inorganic nanoparticles are arranged and the region in which they are not arranged is 30 mV or more (or 40 mV or more, 50 mV or more, or 60 mV or more). [Note 19] The particle-immobilized substrate according to any one of Notes 1 to 18, wherein the potential difference of the zeta potential between the inorganic nanoparticles and the surface of the region of the substrate where the inorganic nanoparticles are not arranged is less than 30 mV (or 25 mV or less, 20 mV or less). [Note 20] The particle immobilization substrate according to any one of Notes 1 to 19, wherein the substrate has a hydroxyl group or a carboxyl group (preferably a hydroxyl group) on the surface of the region where the inorganic nanoparticles are not arranged. [Note 21] The particle-fixed substrate according to any one of Notes 1 to 20, wherein the inorganic nanoparticles are particles in which the inorganic material constituting the inorganic nanoparticles is exposed on the surface.

[0126] [Note 22] A method for manufacturing a particle-immobilized substrate, comprising a substrate having a first region and a second region where the potential difference between their zeta potentials is 30 mV or more (or 40 mV or more, 50 mV or more), wherein inorganic nanoparticles are arranged by electrostatic action in a region with a width of 1 μm or less (or 600 nm or less, 300 nm or less, 150 nm or less) located within the first region. [Note 23] The method for manufacturing a particle-immobilized substrate according to Note 22, wherein the zeta potential of one of the first region and the second region is positive and the zeta potential of the other region is negative. [Note 24] A method for manufacturing a particle-immobilized substrate, comprising a substrate having a first region and a second region in which one zeta potential is positive and the other zeta potential is negative, wherein inorganic nanoparticles are arranged by electrostatic action in a region with a width of 1 μm or less located within the first region. [Note 25] A method for manufacturing a particle-immobilized substrate according to any one of Notes 22 to 24, wherein a plurality of the first regions are arranged regularly on the substrate, and the inorganic nanoparticles are placed within each of the plurality of first regions. [Note 26] A method for manufacturing a particle-immobilized substrate according to any one of Notes 22 to 25, wherein the nanoparticles are one or more selected from the group consisting of metal nanoparticles, semiconductor nanoparticles, and nanocarbon particles (preferably nanocarbon particles, more preferably nanodiamond particles).

[0127] [Note 27] The method for manufacturing a particle-immobilized substrate according to any one of Notes 22 to 26, wherein the zeta potential of the inorganic nanoparticles and the surface of the second region have the same sign. [Note 28] The method for manufacturing a particle-immobilized substrate according to any one of Notes 22 to 27, wherein the zeta potential of the inorganic nanoparticles is negative (preferably a zeta potential of -5mV or less, -10mV or less, or -15mV or less). [Note 29] The method for manufacturing a particle-immobilized substrate according to Note 28, wherein the zeta potential at the surface of the first region of the substrate is positive (preferably 5 mV or more, more preferably 10 mV or more). [Note 30] The method for manufacturing a particle-immobilized substrate according to Note 28 or 29, wherein the zeta potential at the surface of the second region of the substrate is negative (preferably -10 mV or less, more preferably -20 mV or less). [Note 31] The method for manufacturing a particle-immobilized substrate according to any one of Notes 22 to 27, wherein the zeta potential of the inorganic nanoparticles is positive (preferably a zeta potential of 5 mV or more, 10 mV or more, or 20 mV or more). [Note 32] The method for manufacturing a particle-immobilized substrate according to Note 31, wherein the zeta potential at the surface of the first region of the substrate is negative (preferably -10 mV or less, more preferably -20 mV or less). [Note 33] The method for manufacturing a particle-immobilized substrate according to Note 31 or 32, wherein the zeta potential at the surface of the second region of the substrate is positive (preferably 5 mV or more, more preferably 10 mV or more). [Note 34] The method for manufacturing a particle-immobilized substrate according to any one of Notes 22 to 33, wherein the potential difference of the zeta potential between the inorganic nanoparticles and the first region surface is 30 mV or more (or 40 mV or more, 50 mV or more). [Note 35] The method for manufacturing a particle-immobilized substrate according to any one of Notes 22 to 34, wherein the potential difference of the zeta potential between the inorganic nanoparticles and the second region surface is less than 30 mV (or 25 mV or less, 20 mV or less). [Note 36] A method for manufacturing a particle-immobilized substrate according to any one of Notes 22 to 35, wherein the region of the first region and the second region in which the surface data potential is negative has a hydroxyl group or a carboxyl group (preferably a hydroxyl group) on its surface. [Note 37] A method for manufacturing a particle-immobilized substrate according to any one of Notes 22 to 36, wherein the region of the first region and the second region in which the surface data potential is positive has a cationic group (preferably an amino group) on its surface. [Note 38] The method for manufacturing a particle-immobilized substrate according to Note 37, wherein one or more (preferably 2 to 4, more preferably 2) cationic groups are present at one bonding position in a region where the zeta potential is positive. [Note 39] The method for producing a particle-immobilized substrate according to Note 37 or 38, wherein the cationic group has a primary amino group (preferably a primary amino group and a secondary amino group). [Note 40] The method for manufacturing a particle-immobilized substrate according to any one of Notes 22 to 39, wherein the inorganic nanoparticles are particles in which the inorganic material constituting the inorganic nanoparticles is exposed on the surface.

[0128] [Appendix 41] A method for manufacturing a particle-immobilized substrate according to any one of Appendix 22 to 40, further comprising a region AB formation step performed before the electrostatic deposition step, in which two regions A and B with different zeta potentials are formed on the substrate surface, wherein one of the regions A and B is designated as the first region and the other as the second region. [Note 42] The method for manufacturing a particle-immobilized substrate according to Note 41, wherein the region AB formation step comprises: a region A formation step of reacting a reactive functional group present on the substrate with a compound reactive with the reactive functional group to form a region A having a zeta potential different from the zeta potential of the substrate surface before the reaction; and a region B formation step of cleaving at least a portion of the groups formed by the reaction in a part of region A by electron beam irradiation to form a region B having a zeta potential different from the zeta potential of region A. [Appendix 43] A method for manufacturing a particle immobilization substrate according to Appendix 42, wherein a Si substrate is used as the substrate and an amino group-containing silane coupling agent is used as the compound. [Note 44] The method for manufacturing a particle-immobilized substrate according to Note 41, wherein the region AB formation step comprises: a resist mask formation step of forming a resist film on the substrate surface, then dissolving a part of the resist film by electron beam irradiation and development to create holes in the resist film and expose the substrate; a region A formation step of reacting reactive functional groups present on the exposed substrate with a compound that is reactive with said reactive functional groups to form a region A having a zeta potential different from the zeta potential of the substrate surface before the reaction; and a resist removal step of removing the resist film on the substrate surface to expose the substrate surface and form region B.

[0129] [Appendix 45] A method for manufacturing a diamond film-fixed substrate, comprising a CVD step of growing the nanodiamond particles on a particle-fixed substrate according to any one of Appendix 1 to 21, using the nanodiamond particles as a seed, by chemical vapor deposition, to form a diamond film on the substrate. [Appendix 46] The method for manufacturing a diamond film-fixed substrate according to Appendix 45, wherein the diamond film is formed in an area on the substrate with a width of 1 μm or less during the CVD process. [Appendix 47] A method for manufacturing a diamond film-fixed substrate according to Appendix 45 or 46, wherein the CVD process forms an area on the substrate that is not formed with the diamond film and has a width of 1 μm or less.

[0130] [Note 48] A diamond film-fixed substrate comprising a substrate and a diamond film formed on the substrate, wherein the diamond film is formed within a region on the substrate with a width of 1 μm or less, and the arithmetic mean roughness Ra of the surface of the diamond film is 6 nm or more (7 nm or more, 6 to 20 nm, or 7 to 15 nm). [Note 49] The diamond film-fixed substrate according to Note 48, wherein the root mean square height Rq of the diamond film surface is 8 nm or more (10 nm or more, 8 to 30 nm, or 10 to 20 nm). [Note 50] A diamond film-fixed substrate comprising a substrate and a diamond film formed on the substrate, wherein the diamond film is formed within a region on the substrate with a width of 1 μm or less, and the root mean square height Rq of the diamond film surface is 8 nm or more (10 nm or more, 8 to 30 nm, or 10 to 20 nm). [Note 51] A diamond film-fixed substrate according to any one of Notes 48 to 50, having a region on the substrate where the diamond film is not formed and which is less than 1 μm in width. [Note 52] The diamond film fixed substrate according to Note 50, wherein a region on the substrate in which the diamond film is not formed has a width of 1 μm or less, and this region is located within a region on the substrate in which the diamond film is formed.

[0131] [Appendix 53] A method for producing diamond, comprising removing the substrate from the diamond film-fixed substrate described in any one of Appendices 45 to 52 to obtain a diamond derived from the diamond film. [Note 54] The method for producing diamond according to Note 53, wherein the diamond derived from the diamond film is the diamond film or the diamond particles constituting the diamond film. [Explanation of symbols]

[0132] 1. Resin-fixed substrate 2 circuit boards 3. Inorganic Nanoparticles 4 Area A 5. Electron beam irradiation 6 Area B 7. Resist film 7' Electron beam irradiation section 8 Base material surface 10 Diamond film fixed substrate 3' Diamond film 3'a Diamond film surface D1 Particle arrangement region width D2 Particle arrangement region spacing

Claims

1. The system comprises a substrate and a plurality of inorganic nanoparticles arranged on the substrate, The plurality of inorganic nanoparticles are arranged in contact with each other within an area on the substrate with a width of 1 μm or less. A particle-immobilized substrate wherein the zeta potential of the inorganic nanoparticles has the same sign as the zeta potential of the surface of a region of the substrate where the inorganic nanoparticles are not arranged.

2. The system comprises a substrate and inorganic nanoparticles disposed on the substrate, The potential difference between the zeta potential of the inorganic nanoparticles and the zeta potential of the substrate surface at the location where the inorganic nanoparticles are arranged is 30 mV or more. A particle-immobilized substrate wherein the zeta potential of the inorganic nanoparticles has the same sign as the zeta potential of the surface of a region of the substrate where the inorganic nanoparticles are not arranged.

3. The particle-immobilizing substrate according to claim 1 or 2, wherein a plurality of regions with a width of 1 μm or less are regularly arranged on the substrate, and the inorganic nanoparticles are disposed within each of the plurality of regions with a width of 1 μm or less.

4. The particle-immobilized substrate according to any one of claims 1 to 3, wherein the nanoparticles include nanodiamond particles.

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