Method for producing nanocrystalline films

Abstract

To provide a method for manufacturing a nanocrystal film that readily forms a nanocrystal film including at least one kind of a metal oxide and a metal hydroxide and having a desired pattern.SOLUTION: A method for manufacturing a nanocrystal film includes a light emission step of emitting light to a surface of a metal member (110) immersed into water to form a nanocrystal film with a predetermined pattern at the surface of the metal member. The nanocrystal film includes a nanocrystal including at least one kind of an oxide and a hydroxide. The metal member includes a first member including a first metal. The first metal has a standard electrode potential that is higher than -2.00 V. The first member is a pattern structure (22b) having a predetermined pattern. In the light emission step, the nanocrystal film is formed at a surface of the pattern structure. The nanocrystal film has a predetermined pattern that is similar to the pattern structure. The oxide is a first metal oxide. The hydroxide is a first metal hydroxide.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for producing nanocrystalline films. [Background technology]

[0002] Metal oxide thin films have been attracting attention recently and are widely used industrially as semiconductors, insulators, superconductors, transparent conductive films, piezoelectrics, photocatalysts, and protective films, depending on their diverse physical properties. In particular, in recent years, active research has been conducted into optical and electronic devices, focusing on the semiconducting properties of metal oxide thin films. For example, applications of metal oxide thin films to thin film transistors, light-emitting diodes, and various sensors have been promoted. Metal oxides that exhibit semiconducting properties include oxides or composite oxides such as zinc oxide (ZnO), copper oxide (CuO and CuO), titanium oxide (TiO), nickel oxide (NiO), cadmium oxide (CdO), gallium oxide (GaO), indium oxide (InO), tin oxide (SnO), copper aluminum oxide (CuAlO), and indium-gallium-zinc oxide (In-Ga-Zn-O:IGZO).

[0003] Metal oxides with a wide band gap that allows visible light to pass through are suitable for transparent conductive films. Examples of such metal oxides include tin-doped indium oxide (In2O3:Sn, ITO), fluorine-doped tin oxide (SnO2:F, FTO), and aluminum-doped zinc oxide (ZnO:Al). Tungsten oxide (WO3) and niobium oxyfluoride (NbO2F) are also known as electrochromic materials whose optical properties change when an electric field or current is applied. Research is also underway to apply thin films of these electrochromic materials to optical devices.

[0004] The metal oxide thin film is generally produced by sputtering, vacuum deposition, ion plating, laser ablation, sol-gel, hydrothermal synthesis, coprecipitation, or chemical vapor deposition. Also known is a film-forming method in which a metal oxide (oxide semiconductor) precursor is applied to the surface of a substrate by dipping, screen printing, spin coating, spraying, or the like, and the precursor coating is then oxidized by heating or the like.

[0005] On the other hand, nanocrystals made of metal oxides are known to exhibit different physical and chemical properties (melting / sintering temperature, luminescence / fluorescence properties, photocatalytic activity, etc.) from those of the bulk as their size decreases, and research into film formation techniques for metal oxide thin films made of these nanocrystals is also being actively conducted.

[0006] For widespread industrial use of metal oxide thin films, a technology for forming metal oxide thin films only in desired locations on the surface of a substrate (so-called patterning) is required. In particular, precise wiring and arrangement of metal oxide thin films are required for liquid crystal displays and circuit boards, and control of film deposition positions is required for semiconductor devices such as thin film transistors.

[0007] As a method for patterning a metal oxide thin film, the following Patent Documents 1 to 4 disclose a method in which a metal oxide thin film is formed on the entire surface of a substrate by sputtering, vacuum deposition, or the like, and then the metal oxide thin film is patterned by photolithography. In this patterning method, a photosensitive material (photoresist) is applied to the surface of the metal oxide thin film, the metal oxide thin film is exposed to light such as ultraviolet light using a pattern mask, and then the exposed and unexposed areas are removed by development and etching, and the remaining photoresist is peeled off.

[0008] Patent Document 5 discloses a method in which an ink consisting of a metal oxide precursor is directly applied onto a substrate by screen printing or the like, the ink is patterned, and then a metal oxide thin film is formed by heat treatment. Specifically, an amine having a hydroxyl group or an oxygen-containing heterocyclic amine is added to an organic solvent to induce intermolecular hydrogen bonding, thereby improving the viscosity of the precursor ink.

[0009] Non-Patent Document 1 discloses a method for directly forming a pattern consisting of zinc oxide nanoparticles using an aqueous solution method. This patterning method comprises the steps of immersing a substrate in a phenyltrichlorosilane solution to form an organic thin film layer, modifying a portion of the organic thin film layer by exposing it to light using a mask pattern, immersing the organic thin film layer in a palladium (Pd) catalyst solution to support the Pd catalyst on the unmodified portion of the organic thin film layer, and immersing the organic thin film layer in a neutral reaction aqueous solution containing dissolved zinc, thereby selectively promoting the deposition reaction of zinc oxide (ZnO) only in the catalyst-supported portion.

[0010] Non-Patent Document 2 discloses a method for directly forming zinc oxide (ZnO) nanorods using the principle of a galvanic cell, without the need for a seed layer. Specifically, a base metal film such as aluminum is formed on a substrate, and a noble metal film such as platinum (Pt) or copper (Cu) is formed in a desired pattern on the non-metallic film. The substrate is then heated in an aqueous solution containing zinc nitrate or the like. At this time, the Al in the base metal film acts as an anode, dissolving into the aqueous solution and flowing onto the surface of the noble metal film (cathode), causing a hydrothermal synthesis reaction to proceed on the noble metal film side, ultimately resulting in the selective deposition of zinc oxide (ZnO) nanorods on the surface of the noble metal film. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-227300 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-196201 [Patent Document 3] Japanese Patent Application Laid-Open No. 2011-134495 [Patent Document 4] Japanese Patent Application Publication No. 7-304998 [Patent Document 5] Japanese Patent Application Laid-Open No. 2014-143403 [Non-patent literature]

[0012] [Non-Patent Document 1] N. Saito et al., “Characterization of ZincOxide Micropatterns Deposited onSelf-Assembled Monolayer Template”, J. Ceram.Soc. Jpn,vol. 110, no. 5, pp. 386-390, 2002. [Non-patent document 2] Z. Zheng et al., “General Route to ZnONanorod Arrays on Conducting Substrates via Galvanic-cell-based approach”, ScientificReports 3:2434, DOI: 10. 1038, 2013. Summary of the Invention [Problem to be solved by the invention]

[0013] Patterning of metal oxide thin films by photolithography allows for the formation of fine patterns on the order of 1 μm, but the process required for patterning is long and complicated. Furthermore, in the methods described in Patent Documents 1 to 3, the developing solution, etching solution, and stripping solution used in photolithography are strongly acidic or alkaline, which makes patterning dangerous and increases the cost of waste liquids. Furthermore, among metal oxides, amphoteric oxides such as zinc oxide may dissolve during the etching process.

[0014] In the method described in Patent Document 4, a step of washing the metal oxide thin film with water is carried out after exposure, and the parts not irradiated with ultraviolet light are dissolved and removed with water, so that only the parts of the metal oxide thin film that were irradiated with ultraviolet light remain on the surface of the substrate. In this method, the steps up to exposure are generally the same as those in Patent Documents 1 to 3, and problems such as complicated processes and high costs remain.

[0015] The method described in Patent Document 5 does not require vacuum processes such as sputtering and vacuum deposition, or etching processes, and is thought to be suitable for large-area patterning of metal oxide thin films. However, the method described in Patent Document 5 requires high-temperature heat treatment to remove organic solvents, so the substrate on which the metal oxide precursor is printed is limited to heat-resistant glass, etc. Furthermore, it is difficult to form patterns with dimensions of 10 μm or less by screen printing the precursor.

[0016] Furthermore, since the metal oxide thin films formed by the processes described in Patent Documents 1 to 5 have a constant and uniform thickness, it is not possible to form films containing metal oxide nanocrystals by the methods described in Patent Documents 1 to 5.

[0017] The method of Non-Patent Document 1 does not require heat treatment or etching treatment, which broadens the options for substrates and makes it easy to control the shape of the metal oxide thin film. However, the method of Non-Patent Document 1 requires a separate exposure device such as a photolithography device, which increases the process cost and makes it difficult to pattern large-area metal oxide thin films.

[0018] In the method of Non-Patent Document 2, the growth of zinc oxide (ZnO) does not depend on the type of substrate, so conductive substrates such as ITO and FTO can be used. However, hydrothermal synthesis reactions generally require a strongly acidic or alkaline reaction solution and involve high-temperature processes, which places a heavy burden on the environment. Furthermore, metal oxide thin films obtained by hydrothermal synthesis reactions tend to contain impurities, which may reduce the properties of the metal oxide when the metal oxide thin film is applied to the above-mentioned devices.

[0019] The present invention has been made in consideration of the above circumstances, and aims to provide a method for manufacturing a nanocrystalline film that contains at least one of a metal oxide and a metal hydroxide and that can easily form a nanocrystalline film having a desired pattern. [Means for solving the problem]

[0020] A method for producing a nanocrystalline film according to one aspect of the present invention includes a light irradiation step in which a nanocrystalline film having a predetermined pattern is formed on the surface of a metal member immersed in water by irradiating the surface with light, and the nanocrystals contained in the nanocrystalline film include at least one of an oxide and a hydroxide, wherein the oxide is an oxide of a metal derived from the metal member, and the hydroxide is a hydroxide of a metal derived from the metal member.

[0021] The metal member may have a first member containing a first metal and a second member containing a second metal, wherein the standard electrode potential of the first metal may be higher than -2.00 V, the standard electrode potential of the second metal may be higher than -2.00 V, the standard electrode potential of the first metal may be lower than the standard electrode potential of the second metal, and the difference in the standard electrode potentials of the first metal and the second metal may be greater than 0.20 V. The first member and the second member may be electrically connected, the second member may be disposed on the surface of the first member, and the second member may have a predetermined pattern along the surface of the first member. In the light irradiation step, a nanocrystal film may be formed on the surface of the second member, and the oxide contained in the nanocrystals may be an oxide of the first metal, and the hydroxide contained in the nanocrystals may be a hydroxide of the first metal.

[0022] The metal member may have a first member containing a first metal, the standard electrode potential of the first metal may be higher than −2.00 V, the first member may be a patterned structure having a predetermined pattern, the nanocrystal film may be formed on the surface of the first member in the light irradiation step, the oxide contained in the nanocrystals may be an oxide of the first metal, and the hydroxide contained in the nanocrystals may be a hydroxide of the first metal.

[0023] The metal member may have a first member containing a first metal, a substrate, and a conductive film disposed on the surface of the substrate, the standard electrode potential of the first metal may be higher than -2.00 V, the first member and the conductive film may be electrically connected, the conductive film may have a predetermined pattern along the surface of the substrate, in the light irradiation step, a nanocrystal film may be formed on the surface of the conductive film, the oxide contained in the nanocrystals may be an oxide of the first metal, and the hydroxide contained in the nanocrystals may be a hydroxide of the first metal.

[0024] The metal member may have a first member containing a first metal and a mask material overlapping the surface of the first member, water may be interposed between the first member and the mask material, the standard electrode potential of the first metal may be higher than -2.00 V, the exposed portion of the surface of the first member that does not overlap with the mask material may have a predetermined pattern along the surface of the first member, in the light irradiation process, a nanocrystal film may be formed on the surface of the exposed portion, the oxide contained in the nanocrystals may be an oxide of the first metal, and the hydroxide contained in the nanocrystals may be a hydroxide of the first metal.

[0025] The metal member may include an alloy.

[0026] The content of the first metal in the first member may be 10.0 to 100.0 mass % based on the total mass of the first member, and the content of the second metal in the second member may be 10.0 to 100.0 mass % based on the total mass of the second member.

[0027] The pattern structure may have at least one of a mesh structure and a lattice structure.

[0028] The substrate may be at least one selected from the group consisting of glass, ceramics, metals covered with insulating material, semiconductors covered with insulating material, and plastics.

[0029] The conductive film may contain at least one selected from the group consisting of copper, silver, gold, platinum, aluminum, chromium, nickel, iron, tin, lead, indium tin oxide (ITO), fluorine-doped tin oxide (FTO), and aluminum-doped zinc oxide.

[0030] The first member and the conductive film may be connected by a wiring material containing at least one selected from the group consisting of copper, silver, gold, platinum, aluminum, chromium, nickel, iron, tin, and lead.

[0031] The conductive film may include a second metal, the standard electrode potential of the second metal may be greater than −2.00 V, the standard electrode potential of the first metal may be lower than the standard electrode potential of the second metal, and the difference between the standard electrode potentials of the first metal and the second metal may be greater than 0.20 V.

[0032] The area of the exposed portion may be represented as S1, the area of the overlapping portion of the surface of the first member where the mask material overlaps may be represented as S2, and the area ratio S2 / S1 may be 1 / 200 to 1 / 2.

[0033] The light may be sunlight or simulated sunlight.

[0034] In the light spectrum, the wavelength at which the intensity is greatest may be greater than or equal to 360 nm and less than 620 nm.

[0035] The water may be at least one selected from the group consisting of pure water, ion-exchanged water, rainwater, tap water, river water, well water, filtered water, distilled water, reverse osmosis water, spring water, spring water, dam water, and seawater.

[0036] The pH of the water may be 5.00 to 10.0.

[0037] The electrical conductivity of the water may be 0.05 to 1.0 μS / cm.

[0038] The shape of the nanocrystal may be at least one selected from the group consisting of needle-like, column-like, rod-like, tubular, scale-like, block-like, flower-like, starfish-like, branch-like and convex-like shapes.

[0039] The first metal may be at least one selected from the group consisting of aluminum, titanium, manganese, vanadium, zinc, iron, nickel, tin, lead, and copper.

[0040] The method for producing a nanocrystal film according to one aspect of the present invention may further include a film formation step of forming an oxide semiconductor layer on the surface of the metal member before the light irradiation step. [Effects of the Invention]

[0041] According to the present invention, there is provided a method for producing a nanocrystalline film that can easily form a nanocrystalline film containing at least one of a metal oxide and a metal hydroxide and having a desired pattern. [Brief explanation of the drawings]

[0042] [Figure 1] FIG. 1 is a schematic diagram (perspective view) showing a method for producing a nanocrystal film according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram (perspective view) showing a method for producing a nanocrystal film according to one embodiment of the present invention. [Figure 3] (a) in Figure 3 is a schematic diagram (oblique view) of a metal member according to the first embodiment of the present invention, and (b) in Figure 3 is a schematic diagram of a cross section (a cross section perpendicular to the surface of the metal member) of the metal member shown in (a) in Figure 3 and a cross section of a nanocrystalline film formed on the surface of the metal member. [Figure 4] FIG. 4 is a schematic diagram of a metal member (pattern structure) according to a second embodiment of the present invention. [Figure 5](a) in Figure 5 is a schematic diagram of an example of a pattern that the metal member (pattern structure) according to the second embodiment has, (b) in Figure 5 is a schematic diagram of an example of a pattern that the metal member (pattern structure) according to the second embodiment has, and (c) in Figure 5 is a schematic diagram of an example of a pattern that the metal member (pattern structure) according to the second embodiment has. [Figure 6] FIG. 6 is a schematic view (perspective view) of a metal member according to a third embodiment of the present invention. [Figure 7] FIG. 7 is a schematic view (perspective view) of a metal member according to a third embodiment of the present invention. [Figure 8] FIG. 8 is a schematic diagram (top view) of a substrate and a conductive film of a metal member according to a third embodiment of the present invention. [Figure 9] (a) in Figure 9 is a schematic diagram (oblique view) of a metal member according to the fourth embodiment of the present invention, (b) in Figure 9 is a schematic diagram of a cross section (cross section perpendicular to the surface of the metal member) of the metal member shown in (a) in Figure 9, and (c) in Figure 9 is a schematic diagram of a cross section (cross section perpendicular to the surface of the metal member) of the metal member shown in (a) in Figure 9 and a cross section of a nanocrystalline film formed on the surface of the metal member. [Figure 10] (a) in Figure 10 is a schematic diagram (oblique view) of a metal member according to the fourth embodiment of the present invention, (b) in Figure 10 is a schematic diagram of a cross section (cross section perpendicular to the surface of the metal member) of the metal member shown in (a) in Figure 10, and (c) in Figure 10 is a schematic diagram of a cross section (cross section perpendicular to the surface of the metal member) of the metal member shown in (a) in Figure 10 and a cross section of a nanocrystalline film formed on the surface of the metal member. [Figure 11] FIG. 11 is an image taken with a scanning electron microscope (SEM) showing rod-shaped nanocrystals according to an embodiment of the present invention. [Figure 12] FIG. 12 is an image taken with a scanning electron microscope (SEM) showing flower-shaped nanocrystals according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0043] Preferred embodiments of the present invention are described in detail below. However, the present invention is not limited to the following embodiments. The term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, as long as their purpose is achieved. Numerical ranges indicated using "to" include the numerical values before and after "to" as the minimum and maximum values, respectively. When multiple substances corresponding to each component are present in the composition, the content of each component in a composition refers to the total content of the multiple substances present in the composition, unless otherwise specified. In the drawings, equivalent components are designated by the same symbols.

[0044] [Outline of nanocrystalline film manufacturing method] The method for producing a nanocrystalline film according to the present invention includes a light irradiation step. For example, as shown in FIG. 1 , in the light irradiation step, light L is irradiated onto the surface of a metal member 100 immersed in water 2, thereby forming a nanocrystalline film having a predetermined pattern on the surface of the metal member 100. The predetermined pattern refers to a shape that is designed and determined in advance before the nanocrystalline film is formed. The nanocrystalline film may be an aggregate of multiple (numerous) nanocrystals. The nanocrystalline film may be a polycrystal containing multiple (numerous) nanocrystals. The nanocrystalline film may be composed solely of nanocrystals. The nanocrystals contained in the nanocrystalline film include at least one of an oxide and a hydroxide, where the oxide is an oxide of a metal derived from the metal member 100, and the hydroxide is a hydroxide of a metal derived from the metal member 100. The method for producing a nanocrystalline film according to the present invention may also be referred to as a nanocrystalline film patterning method. The method for producing a nanocrystalline film according to the present invention may further include a film formation step of forming an oxide semiconductor layer on the surface of the metal member before the light irradiation step.

[0045] Four embodiments of the present invention that differ in the metal member will be described below, but the method for producing a nanocrystalline film according to the present invention is not limited to the following four embodiments.

[0046] [First embodiment] As shown in FIG. 3A, the metal member 100 according to the first embodiment of the present invention includes a first member 22a including a first metal and a second member 24 including a second metal. The first metal is different from the second metal. The standard electrode potential of the first metal is higher than −2.00 V. The standard electrode potential of the second metal is also higher than −2.00 V. The standard electrode potential of the first metal is lower than the standard electrode potential of the second metal, and the difference between the standard electrode potentials of the first metal and the second metal is greater than 0.20 V. The first member 22a and the second member 24 are electrically connected. The second member 24 is disposed on the surface of the first member 22a and has a predetermined pattern along the surface of the first member 22a. For example, as shown in FIG. 3A, the predetermined pattern of the second member 24 is a plurality of rectangles extending along the surface of the first member 22a and parallel to each other. However, the predetermined pattern of second member 24 is not limited to this and may be changed according to the design needs of the target nanocrystalline film. For example, the predetermined pattern of second member 24 may be a wiring pattern such as straight lines or curves, a graphic such as a polygon or circle, or a character.

[0047] As shown in FIG. 3B, in the light irradiation step, a nanocrystalline film 25 having a predetermined pattern is formed on the surface of the second component 24. The predetermined pattern of the nanocrystalline film 25 is the same as the pattern of the second component 24. That is, in the cases of FIGS. 3A and 3B, the predetermined pattern of the nanocrystalline film 25 is a plurality of rectangular shapes extending along the surface of the first component 22 and parallel to each other. The nanocrystals contained in the nanocrystalline film 25 include at least one of an oxide and a hydroxide of the first metal. For example, as shown in FIG. 3B, the nanocrystalline film 25 may have a hydroxide film 25a covering part or the entire surface of the second component 24 and oxide rods 25b (nanorods) extending from the surface of the hydroxide film 25a. The position and orientation of the oxide rods 25b are not limited. For example, the oxide rods 25b may extend vertically from the hydroxide film 25a covering the upper surface of the second component 24. Oxide rods 25b may extend laterally from hydroxide film 25a covering the side surface of second member 24. Hydroxide film 25a may be a hydroxide of the first metal, and oxide rods 25b may be an oxide of the first metal. Nanocrystalline film 25 may consist only of an oxide and a hydroxide of the first metal. Nanocrystalline film 25 may consist only of an oxide of the first metal. Nanocrystalline film 25 may consist only of a hydroxide of the first metal.

[0048] Hereinafter, nanocrystals containing at least one of an oxide of a first metal and a hydroxide of the first metal will be referred to as "first nanocrystals." Nanocrystals containing at least one of an oxide of a second metal and a hydroxide of the second metal will be referred to as "second nanocrystals." In the light irradiation step, the first nanocrystals may be preferentially (selectively) generated. One reason for the preferential generation of the first nanocrystals is galvanic corrosion caused by the electrical connection between the first member and the second member. The mechanism by which the first nanocrystals are preferentially generated on the surface of the second member will be described below. Note that the mechanism by which nanocrystals are generated in the first embodiment is not limited to the following mechanism.

[0049] When the first and second members are not electrically connected, the light irradiation process involves submerged photosynthesis of crystallites (SPSC) occurring on the surfaces of the first and second members. Generally, SPSC is a method of forming nanocrystals on the surface of a metal member immersed in water by irradiating the surface with light. When the first and second members are not electrically connected, first nanocrystals are generated on the surface of the first member by SPSC, and second nanocrystals are generated on the surface of the second member by SPSC. The mechanism of SPSC in the first member is common to that of SPSC in the second member. Below, we will explain the general corrosion reaction of metals, followed by the mechanism of SPSC in the first member.

[0050] When a first member containing a first metal (M) is immersed in water, a reaction occurs in which the first metal corrodes. That is, the first metal is ionized in water, and as shown in the following reaction formula (1), the ions of the first metal (M n+ ) is produced. Generally, the corrosion reaction of a metal is a combination of an anodic reaction in which the metal dissolves as metal ions, and a cathodic reaction in which an oxidant in the water is reduced. The reaction shown in the following reaction formula (1) is an anodic reaction. The reactions shown in the following reaction formulas (2) and (3) are both cathodic reactions. The reaction shown in the following reaction formula (2) occurs when the water is acidic. The reaction shown in the following reaction formula (3) occurs when the water is neutral or alkaline, or when the water contains dissolved oxygen. Here, when the standard electrode potential of the metal is positive, it is generally thought that the anodic reaction shown in the following reaction formula (1) does not occur. However, if hydrogen ions (H + Depending on the concentration of M or the concentration of dissolved oxygen, the metal ionizes, and as shown in the following reaction formula (4), n+ The metal ions (M + ) is, for example, in water containing dissolved oxygen, the hydroxide ion (OH -As a result, as shown in the following reaction formula (5), hydroxide (M(OH) n ) is produced. Then, water molecules are released from the hydroxide, and the oxide (MO) is produced, as shown in the following reaction formula (6). x However, in the above-described general metal corrosion reaction, it is difficult to produce hydroxides and oxides with high crystallinity. In other words, the hydroxides and oxides produced in the general metal corrosion reaction have poorer crystallinity than the nanocrystals obtained by the SPSC of the first embodiment. M→M n+ +ne - (1) 2H + +2e - →H2(2) O2+2H2O+4e - →4OH - (3) 2M+O2+2nH + →2M n+ +2H2O (4) M n+ +nOH - →M(OH) n (5) M(OH) n →MO x +(nx)H2O (6)

[0051] Hydroxide ions can be generated by reactions other than those of the above reaction formula (3). For example, hydroxide ions can be generated by dissociation of water molecules, or by using alkaline water. However, these hydroxide ions cannot be converted into hydroxide (M(OH) n ) and oxides (MO x The reaction that occurs is the general metal corrosion reaction described above. In this case, nanocrystals like those obtained in the SPSC of the first embodiment are not formed.

[0052] In the first embodiment, it is assumed that nanocrystals are generated by using SPSC through the mechanism shown below. When the first member and the second member are not electrically connected and first nanocrystals are generated on the surface of the first member, the reactions shown in the above reaction formulas (1) to (5) first occur. Then, in the light irradiation step, the hydroxide of the first metal (M(OH) n ) to the oxide of the first metal (MO x ) grow on the surface of the first component. For example, the hydroxide of the first metal reacts with hydroxide ions (OH - ) to form the hydroxo complex ions of the first metals ([M(OH) x ] y- ) is formed and redissolves in water. The higher the pH of the water, the more easily hydroxo complex ions are generated. Then, at least a part of the hydroxo complex ions is transformed into nanocrystals. The nanocrystals contain at least one of hydroxide and oxide. For example, when the metal (M) is zinc (Zn), the reaction shown in the following reaction formula (7) produces tetrahydroxozincate(II) ions ([Zn(OH)4] 2- ) is generated. Then, ZnO nanocrystals are generated by the reaction shown in the following reaction formula (8). Here, the nanocrystals may be formed, for example, by photoinduced tip growth. Photoinduced tip growth means that the tip growth of columnar or needle-like crystals is promoted by light irradiation. Note that the mechanism by which nanocrystals are generated is not limited to the above reaction mechanism. Zn(OH)2+2OH - →[Zn(OH)4] 2- (7) [Zn(OH)4] 2- →ZnO+2OH - +H2O (8)

[0053] In the light irradiation step, when the water in which the metal member is immersed is irradiated with light, radiolysis of water may occur. The decomposition species include hydrogen radicals (H ), hydroxyl radicals ( OH), and hydrated electrons (e aq - Of these, the hydroxyl radical reacts with the hydrated electron to immediately produce hydroxide ions (OH -In the light irradiation step, the reaction between the hydroxyl radicals and hydrated electrons may promote the generation of hydroxide ions, thereby promoting the generation of nanocrystals. In other words, in the light irradiation step, a photochemical reaction accompanied by the generation of radicals may occur.

[0054] Next, the first and second members are electrically connected, and galvanic corrosion occurs, causing the first nanocrystals to be preferentially formed on the surface of the second member. The reaction mechanism is described below.

[0055] The standard electrode potential of the first metal contained in the first component is higher than -2.00 V. The standard electrode potential of the second metal contained in the second component is higher than -2.00 V. The standard electrode potential is the potential generated during the exchange of electrons in a redox reaction system in a liquid. The electrode reactions of each element in water and the standard electrode potential of each element are shown in Tables 1 and 2. The standard electrode potential is also used as a measure of the susceptibility of a metal to corrosion. Metals that are easily soluble in water and easily ionize have a low standard electrode potential. By using first and second metals with standard electrode potentials higher than -2.00 V, excessive reactions between the first and second metals and water (direct reactions between the first and second metals and water) can be suppressed. As a result, nanocrystals can be effectively produced using SPSC.

[0056] [Table 1]

[0057] [Table 2]

[0058] Galvanic corrosion occurs when two metals with different standard electrode potentials come into contact in water. The metal with the lower standard electrode potential is called the "base metal." The metal with the higher standard electrode potential is called the "noble metal." The corrosion rate of a base metal immersed in water together with a noble metal is higher than the corrosion rate of the base metal immersed alone in water. The corrosion rate of a noble metal immersed in water together with a base metal is lower than the corrosion rate of the noble metal immersed alone in water. In the first embodiment, the standard electrode potential of the first metal is lower than the standard electrode potential of the second metal. That is, the first metal is a base metal and the second metal is a noble metal. When the first metal is a base metal and the second metal is a noble metal, galvanic corrosion occurs, causing the first component containing the baser first metal to corrode preferentially, and the first metal to dissolve in water preferentially over the second metal. That is, when the metal M is a less noble first metal, the rate of the reaction shown in the above reaction formula (1) increases due to galvanic corrosion.

[0059] Since the first and second members are electrically connected, the electrons (e - ) flows from the first member to the second member, and the cathodic reaction of the above reaction formula (2) or (3) occurs preferentially on the surface of the second member. In particular, when the water is neutral or alkaline, or when the water contains dissolved oxygen, the reaction shown in the above reaction formula (3) proceeds. As a result, hydroxide ions (OH - ) concentration increases, and the first metal ions (M n+ ) (the formation of the hydroxide of the first metal shown in reaction formula (5) above) and the subsequent formation of the first nanocrystals by SPSC (the above reaction formulas (7) and (8)) are promoted. On the other hand, the corrosion reaction of the second metal is suppressed by galvanic corrosion. In other words, when metal M is a noble second metal, the rate of the reaction shown in reaction formula (1) above is reduced. As a result, the formation of the hydroxide of the second metal shown in reaction formula (5) above and the subsequent formation of the second nanocrystals by SPSC are suppressed. Therefore, the first nanocrystals are preferentially formed on the surface of the second component.

[0060] The hydroxide ions (OH - ) can be generated by reactions other than the above reaction formula (3). For example, as shown in the following reaction formula (9), the electrons (e - ) at the interface between the second component and water. aq - ) is then converted into hydroxyl radicals (·OH) and hydrated electrons (e aq - ) reacts with hydroxide ions (OH - ) is generated near the surface of the second member. - ) concentration increases, and thus, in the same manner as described above, the formation of the hydroxide of the first metal according to reaction formula (5) above and the SPSC reaction according to reaction formulas (7) and (8) above proceed preferentially on the surface of the second component. e - →e aq - (9) OH+e aq - →OH - (10)

[0061] From the viewpoint of the reactivity of the first metal with water and the solubility of the ions of the first metal in water, the standard electrode potential of the first metal is preferably higher than −2.00 V and not higher than 1.00 V, more preferably −1.80 to 0.80 V, and even more preferably −1.70 to 0.60 V.

[0062] From the viewpoint of the reactivity of the second metal with water and the solubility of the ions of the second metal in water, the standard electrode potential of the second metal is preferably higher than −2.00 V and not higher than 1.60 V, more preferably −1.80 to 1.60 V, and even more preferably −1.70 to 1.60 V.

[0063] The first metal may be, for example, at least one selected from the group consisting of copper, bismuth, tungsten, lead, tin, molybdenum, nickel, cobalt, indium, cadmium, iron, zinc, chromium, ytterbium, niobium, vanadium, manganese, zirconium, titanium, aluminum, thorium, beryllium, and europium.

[0064] The second metal is selected to be different from the first metal, and may be, for example, at least one metal selected from the group consisting of gold, platinum, iridium, palladium, silver, rhodium, copper, bismuth, tungsten, lead, tin, molybdenum, nickel, cobalt, indium, cadmium, iron, zinc, chromium, ytterbium, niobium, vanadium, manganese, zirconium, and titanium.

[0065] The combination of the first metal and the second metal is not particularly limited as long as the standard electrode potential of the first metal is lower than the standard electrode potential of the second metal and the difference in the standard electrode potentials of the first metal and the second metal is greater than 0.20 V. The combination of the first metal and the second metal may be, for example, zinc as the first metal and copper as the second metal. The first metal may be zinc and tungsten as the second metal. The first metal may be zinc and nickel as the second metal. The first metal may be zinc and silver as the second metal. The first metal may be aluminum and copper as the second metal. The first metal may be titanium and tungsten as the second metal.

[0066] The first member is not particularly limited as long as it contains the first metal. The first member may consist only of the first metal. The first member may contain an oxide of the first metal in addition to the first metal (simple substance). However, a member consisting only of an oxide of the first metal does not qualify as the first member. From the viewpoint of nanocrystal growth, the content of the first metal in the first member is preferably 10.0 to 100.0 mass%, more preferably 15.0 to 100.0 mass%, and even more preferably 20.0 to 100.0 mass%, based on the total mass of the first member. The higher the content of the first metal in the first member, the easier it is to generate an oxide or hydroxide and to control the composition of the oxide or hydroxide.

[0067] The second component is not particularly limited as long as it contains the second metal. The second component may consist solely of the second metal. The second component may contain an oxide of the second metal in addition to the second metal (simple substance). However, a component consisting solely of an oxide of the second metal does not qualify as the second component. From the viewpoint of nanocrystal growth, the content of the second metal in the second component is preferably 10.0 to 100.0 mass%, more preferably 15.0 to 100.0 mass%, and even more preferably 20.0 to 100.0 mass%, based on the total mass of the second component. The higher the content of the second metal in the second component, the easier it is to generate an oxide or hydroxide and to control the composition of the oxide or hydroxide.

[0068] The metal member may contain an alloy. The first member may contain an alloy of the first metal, or may consist solely of an alloy of the first metal. The composition of the alloy of the first metal is not particularly limited. The alloy of the first metal may be, for example, an iron alloy, a copper alloy, a zinc alloy, etc. The second member may contain an alloy of the second metal, or may consist solely of an alloy of the second metal. The composition of the alloy of the second metal is not particularly limited as long as it contains the second metal. The alloy of the second metal may be, for example, an iron alloy, a copper alloy, a zinc alloy, etc. When the first metal is an alloy, the standard electrode potential of the first metal may be the standard electrode potential of the alloy. When the second metal is an alloy, the standard electrode potential of the second metal may be the standard electrode potential of the alloy.

[0069] Examples of iron alloys include Fe—C alloys, Fe—Au alloys, Fe—Al alloys, Fe—B alloys, Fe—Ce alloys, Fe—Cr alloys, Fe—Cr—Ni alloys, Fe—Cr—Mo alloys, Fe—Cr—Al alloys, Fe—Cr—Cu alloys, Fe—Cr—Ti alloys, Fe—Cr—Ni—Mn alloys, Fe—Cu alloys, Fe—Ga alloys, Fe—Ge alloys, Fe—Mg alloys, Fe—Mn alloys, Fe—Mo alloys, Fe—N alloys, Fe—Nb alloys, Fe—Ni alloys, Fe—P alloys, Fe—S alloys, Fe—Si alloys, Fe—Si—Ag alloys, Fe—Si—Mg alloys, Fe—Ti alloys, Fe—U alloys, Fe—V alloys, Fe—W alloys, and Fe—Zn alloys.

[0070] Examples of copper alloys include Cu-Sn alloys, Cu-Ni alloys, Cu-Zn alloys, Cu-P alloys, Cu-Sn-P alloys, Cu-Al alloys, Cu-Zn-Sn alloys, Cu-Zn-Mn alloys, Cu-Zn-Si alloys, Cu-Zn-Ni alloys, Cu-Mn alloys, Cu-Be alloys, Cu-Ag alloys, and Cu-Zr alloys.

[0071] Examples of zinc alloys include Zn-Ni based alloys, Zn-Sb based alloys, Zn-Cu based alloys, Zn-Al based alloys, and Zn-Mg based alloys.

[0072] From the viewpoint of nanocrystal growth, the content of the first metal in the alloy of the first metal is preferably 10.0 to 99.8 mass%, more preferably 15.0 to 99.5 mass%, and even more preferably 20.0 to 99.9 mass%. From the viewpoint of nanocrystal growth, the content of the second metal in the alloy of the second metal is preferably 10.0 to 99.8 mass%, more preferably 15.0 to 99.5 mass%, and even more preferably 20.0 to 99.9 mass%.

[0073] The first component may further contain other atoms that are unavoidably mixed in. The content of the other atoms that are unavoidably mixed in may be, for example, 3% by mass or less, based on the total mass of the first component. From the viewpoint of nanocrystal growth, the content of the above atoms contained in the first component is preferably 1% by mass or less. The second component may further contain other atoms that are unavoidably mixed in. The content of the other atoms that are unavoidably mixed in may be, for example, 3% by mass or less, based on the total mass of the second component. From the viewpoint of nanocrystal growth, the content of the above atoms contained in the second component is preferably 1% by mass or less.

[0074] The shape of the first member is not particularly limited. Examples of the shape of the first member include a plate, a block, a round wire, a sheet, or a combination of these. From the viewpoint of workability in immersing in water, the shape of the first member is preferably a plate, a block, or a sheet.

[0075] The method for forming the second member (the method for patterning the second member on the surface of the first member) is not particularly limited. For example, the second member may be formed on the entire surface of the first member by sputtering, vacuum deposition, pulse laser deposition (PLD), or the like, and then processed into a desired shape (pattern) by photolithography, a milling cutter, or the like. The second member may be processed into a desired shape (pattern) by forming a photoresist pattern on the surface of the first member, subsequently depositing the second member on the surface of the first member, and then removing the photoresist. The second member may be processed into a desired pattern by depositing the second member on the entire surface of the first member, applying photoresist to the second member, irradiating the photoresist with laser light, and partially removing the second member. The pattern of the second member may be deposited on the surface of the first member using a stencil mask. After forming a film of the second member on the entire surface of the first member by electroless plating, pulsed light or the like may be irradiated onto predetermined locations of the second member to adhere only predetermined locations of the second member to the surface of the first member. A pattern of the second member may be formed by applying a paste containing the second metal to the surface of the first member by screen printing, inkjet printing, or the like, and then sintering or hardening the paste by heating or the like. In the above patterning method, the patterning conditions may be appropriately selected so as to avoid dissolution, corrosion, or peeling of the metal member by the chemical solution, or excessive oxidation of the metal member by heat treatment.

[0076] [Second embodiment] The second embodiment of the present invention will be described below, and in the following, explanations of matters common to the first and second embodiments will be omitted in some cases.

[0077] The metal member according to the second embodiment has a first member containing a first metal. The standard electrode potential of the first metal is higher than −2.00 V. The metal member according to the second embodiment may consist solely of the first member. The first member is a pattern structure having a predetermined pattern. As shown in FIG. 4, the predetermined pattern of the pattern structure 22b may be, for example, a mesh structure. In the light irradiation step, a nanocrystal film containing nanocrystals is formed on the surface of the first member (i.e., the pattern structure 22b). That is, in the light irradiation step, the nanocrystal film is formed on part or the entire surface of the pattern structure 22b. That is, the nanocrystal film has the same pattern as the pattern structure 22b. The nanocrystals contained in the nanocrystal film include at least one of an oxide of the first metal and a hydroxide of the first metal. The nanocrystal film may consist solely of an oxide of the first metal and a hydroxide of the first metal. The nanocrystal film may consist solely of an oxide of the first metal. The nanocrystal film may consist solely of a hydroxide of the first metal. Since the metal member 110 (first member) of the second embodiment is a pattern structure 22b, there is no need to prepare the metal member before the light irradiation process, and there is no need to perform a separate patterning process (photolithography, etc.) after forming the nanocrystalline film.

[0078] As described below, the inventors speculate that the mechanism of nanocrystalline film formation in the second embodiment is the same as that in the first embodiment, except that the second member is not used.

[0079] By irradiating the surface of the first member (pattern structure) immersed in water with light, the reactions shown in the above reaction formulas (1) to (5) occur, and the hydroxide of the first metal (M(OH) n ) is generated on the surface of the patterned structure. The tip of the nanocrystal then grows according to the reactions shown in the above reaction formulas (7) and (8). Note that the reactions of the above formulas (7) and (8) are reactions when the first metal M is zinc, but can occur when other first metals are used.

[0080] The pattern structure is a member containing a first metal that has been processed into a two-dimensional or three-dimensional pattern. The pattern structure may have at least one of a mesh structure and a lattice structure. The pattern structure 22b shown in FIG. 4 is a sample stage (sample mesh) used for observation with a transmission electron microscope. The sample mesh for a transmission electron microscope is a metal that has been subjected to mesh processing, and is preferably used as the pattern structure (first member).

[0081] The patterned structure may be manufactured by existing methods such as plain weaving of wires made of the first metal, punch press, photoetching, etc. Alternatively, the patterned structure may be manufactured by forming a structure having a predetermined pattern using a material other than the first metal, and then coating the surface of this structure with the first metal by a method such as plating.

[0082] The predetermined pattern of the pattern structure is not particularly limited. For example, as shown in Figures 4 and 5(a), the pattern structure 22b may have a mesh structure. As shown in Figure 5(b), the pattern structure 22b may have a plurality of circular holes having the same inner diameter formed at equal intervals. As shown in Figure 5(c), the pattern structure 22b may have a honeycomb structure in which a plurality of hexagonal holes having the same size are formed at equal intervals.

[0083] The standard electrode potential of the first metal contained in the pattern structure (first member) is preferably higher than -2.00 V and not higher than 1.00 V, more preferably -1.80 to 0.80 V, and even more preferably -1.70 to 0.60 V, from the viewpoints of the reactivity of the first metal with water and the solubility of the ions of the first metal in water.

[0084] The first metal contained in the pattern structure (first member) may be, for example, at least one selected from the group consisting of copper, bismuth, tungsten, lead, tin, molybdenum, nickel, cobalt, indium, cadmium, iron, zinc, chromium, ytterbium, niobium, vanadium, manganese, zirconium, titanium, aluminum, thorium, beryllium, and europium.

[0085] The pattern structure (first member) may contain an alloy of the first metal, or may consist solely of an alloy of the first metal. The composition of the alloy of the first metal is not particularly limited. The alloy of the first metal may be, for example, an iron alloy, a copper alloy, a zinc alloy, etc.

[0086] From the viewpoint of nanocrystal growth, the content of the first metal in the pattern structure (first member) is preferably 10.0 to 100.0 mass% based on the total mass of the first member, more preferably 15.0 to 100.0 mass%, and even more preferably 20.0 to 100.0 mass%. The higher the content of the first metal in the pattern structure, the easier it is for an oxide or hydroxide to be generated on the surface of the pattern structure, and the easier it is to control the composition of the oxide or hydroxide.

[0087] The composition of the pattern structure (first member) may be the same as the composition of the first member in the first embodiment.

[0088] [Third embodiment] The third embodiment of the present invention will be described below, in which explanations of matters common to the first, second and third embodiments will be omitted in some cases.

[0089] As shown in FIGS. 6 and 7 , a metal member 130 according to the third embodiment includes a first member 22c containing a first metal, a substrate 26, and a conductive film 28 disposed on the surface of the substrate 26. The standard electrode potential of the first metal is higher than −2.00 V. The first member 22c and the conductive film 28 are electrically connected by a wiring material 30. The conductive film 28 has a predetermined pattern along the surface of the substrate 26. In the light irradiation step, a nanocrystalline film is formed on part or the entire surface of the conductive film 28. That is, the nanocrystalline film has the same pattern as the conductive film 28. The nanocrystals contained in the nanocrystalline film include at least one of an oxide of the first metal and a hydroxide of the first metal. The nanocrystalline film may be composed only of an oxide of the first metal and a hydroxide of the first metal. The nanocrystalline film may be composed only of an oxide of the first metal. The nanocrystalline film may be composed only of a hydroxide of the first metal.

[0090] As described below, the inventors speculate that the nanocrystal generation mechanism in the third embodiment is the same as that in the first embodiment, except that the conductive film has the same electrochemical function as the second member.

[0091] The reaction shown in the above reaction formula (1) occurs in water, and the first metal in the first component is converted into the first metal ion (M n+ ) and electrons (e - ) is generated. Since the first member and the conductive film are electrically connected, electrons (e - ) flows from the first member into the conductive membrane, and the cathodic reaction shown in the above reaction formula (2) or (3) occurs preferentially on the surface of the conductive membrane. In particular, when the water is neutral or alkaline, or when the water contains dissolved oxygen, the reaction shown in the above reaction formula (3) proceeds. As a result, hydroxide ions (OH - ) concentration increases, and hydroxide ions (OH - ) and ions of the first metal (M n+) (the production of the hydroxide of the first metal shown in the above reaction formula (5)) and the subsequent production of the first nanocrystals by SPSC (the reactions shown in the above reaction formulas (7) and (8)). At this time, the corrosion reaction of the conductive film is suppressed by galvanic corrosion.

[0092] The hydroxide ions (OH - ) can be generated by reactions other than the reaction of the above reaction formula (3). For example, as shown in the above reaction formula (9), electrons (e - ) at the interface between the conductive film and water. aq - ) is then converted into hydroxyl radicals (·OH) and hydrated electrons (e aq - ) reacts with hydroxide ions (OH - ) is generated near the surface of the conductive film. - ) increases, the formation of the hydroxide of the first metal according to the above reaction formula (5) and the SPSC reaction according to the above reaction formulas (7) and (8) proceed preferentially on the surface of the conductive film.

[0093] From the viewpoint of the reactivity of the first metal with water and the solubility of the ions of the first metal in water, the standard electrode potential of the first metal is preferably higher than −2.00 V and not higher than 1.00 V, more preferably −1.80 to 0.80 V, and even more preferably −1.70 to 0.60 V.

[0094] The first metal may be, for example, at least one selected from the group consisting of copper, bismuth, tungsten, lead, tin, molybdenum, nickel, cobalt, indium, cadmium, iron, zinc, chromium, ytterbium, niobium, vanadium, manganese, zirconium, titanium, aluminum, thorium, beryllium, and europium.

[0095] The first member may contain an alloy of the first metal, or may consist solely of an alloy of the first metal. The composition of the alloy of the first metal is not particularly limited. The alloy of the first metal may be, for example, an iron alloy, a copper alloy, a zinc alloy, or the like.

[0096] From the viewpoint of nanocrystal growth, the content of the first metal in the first component is preferably 10.0 to 100.0 mass%, more preferably 15.0 to 100.0 mass%, and even more preferably 20.0 to 100.0 mass%, based on the total mass of the first component. The higher the content of the first metal in the first component, the easier it is to generate an oxide or hydroxide, and the easier it is to control the composition of the oxide or hydroxide.

[0097] The composition of the first member of the third embodiment may be the same as the composition of the first member of the first embodiment.

[0098] The material of the substrate on which the conductive film is formed is not particularly limited. The substrate may be at least one selected from the group consisting of glass, ceramics, metals covered with an insulating material, semiconductors covered with an insulating material, and plastics. The substrate may be a resin film selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyarylate (PAR), polyethersulfone (PES), polycarbonate (PC), and polyimide (PI), or a combination thereof. The material of the substrate may be appropriately selected depending on the properties required for the device to which the nanocrystalline film pattern is applied (e.g., transparency, dimensional stability, solvent resistance, heat resistance, gas barrier properties, and moisture absorption resistance), reactivity with water, adhesion to the conductive film, etc.

[0099] It is preferable that the nanocrystalline film is not formed on the surface of the substrate. In other words, it is preferable that the nanocrystalline film pattern is selectively formed only on the surface of the conductive film out of the surface of the conductive film and the surface of the substrate itself. By suppressing the flow of electrons generated in the first component into the substrate itself, the formation of the nanocrystalline film on the surface of the substrate is suppressed. In this respect, the volume resistivity of the substrate is 1×10 1It is preferable that the resistance is Ωcm or more, and 1×10 2 It is more preferable that the resistance is 1×10 Ωcm or more. 3 It is more preferable that the resistivity is Ωcm or more.

[0100] The conductive film may include at least one selected from the group consisting of copper, silver, gold, platinum, aluminum, chromium, nickel, iron, tin, lead, indium tin oxide (ITO), fluorine-doped tin oxide (FTO), and aluminum-doped zinc oxide. The conductive film may be equivalent to the second member in electrochemical function. That is, the conductive film may include a second metal, and the standard electrode potential of the second metal may be higher than −2.00 V, the standard electrode potential of the first metal may be lower than the standard electrode potential of the second metal, and the difference in the standard electrode potentials of the first metal and the second metal may be greater than 0.20 V. The composition of the conductive film may be the same as that of the second member of the first embodiment.

[0101] The method for forming a conductive film (the method for patterning a conductive film on the surface of a substrate) is not particularly limited. For example, a conductive film may be formed on the entire surface of the substrate by sputtering, vacuum deposition, pulsed laser deposition (PLD), or the like, and then processed into a desired shape (pattern) by photolithography, a milling cutter, or the like. A photoresist pattern may be formed on the surface of the substrate, a conductive film may be subsequently deposited on the surface of the substrate, and the photoresist may then be removed to process the conductive film into a desired shape (pattern). A conductive film may be formed on the entire surface of the substrate, a photoresist may be applied to the substrate, and the photoresist may be irradiated with laser light and the conductive film may be partially removed to process the conductive film into a desired pattern. A stencil mask may be used to vapor-deposit a conductive film pattern onto the surface of the substrate. A conductive film may be formed on the entire surface of the substrate by electroless plating, and then pulsed light or the like may be irradiated to predetermined locations of the conductive film to adhere only predetermined locations of the conductive film to the surface of the substrate. A paste containing the raw materials for the conductive film may be applied to the surface of the substrate by screen printing, inkjet printing, or the like, and the paste may be sintered or cured by heating or the like, thereby forming a pattern of the conductive film.

[0102] The electrons (e - ) into the conductive film and the growth of nanocrystals by the SPSC reaction is promoted on the surface of the conductive film, the volume resistivity of the conductive film is not particularly limited. From the viewpoint of uniformity of nanocrystal growth, the volume resistivity of the conductive film is, for example, 1 × 10 0 It is preferable that the resistance is Ωcm or less, and 1×10 -1 It is more preferable that the resistance is 1×10 Ωcm or less. -2 It is more preferable that the resistivity is Ωcm or less.

[0103] The method for electrically connecting the first member and the conductive film is not particularly limited. For example, the first member and the conductive film may be electrically connected via a conductive material. The electrical connection between the first member and the conductive film does not mean an electrical connection via water. The first member and the substrate may be electrically connected as long as the generation of a nanocrystalline film on the surface of the substrate itself is suppressed.

[0104] The arrangement of the first member and the substrate in the metal member is not particularly limited. From the viewpoints of workability and nanocrystalline film production, the arrangement of the first member and the substrate in the metal member is preferably the arrangement shown in FIG. 6 or FIG. 7. As shown in FIG. 6, the first member 22c and the substrate 26 may be electrically connected via a wiring material 30, and a conductive film 28 disposed on the surface of the substrate 26 may be electrically connected to the wiring material 30. In the case of FIG. 6, one end of the wiring material 30 is wrapped around the first member 22c, and the other end of the wiring material 30 is wrapped around the substrate 26. As shown in FIG. 7, the wiring material 30 may be composed of a metal wire 32 and a brazing material 34 connected to both ends of the metal wire 32. The brazing material 34 may be solder. In the case of FIG. 7, one end of the metal wire 32 is connected to the first member 22c via the brazing material 34, and the other end of the metal wire 32 is connected to the substrate 26 and the conductive film 28 via another brazing material 34.

[0105] The wiring material 30 connecting the first member 22c and the conductive film 28 may contain at least one selected from the group consisting of copper, silver, gold, platinum, aluminum, chromium, nickel, iron, tin, and lead.

[0106] The solder may be Sn-Pb solder, Sn-Pb-Ag solder, Sn-Ag-Cu solder, etc. Considering the impact on the environment, the solder is preferably Sn-Ag-Cu solder, which is substantially lead-free. When using solder to make an electrical connection, the solder may be heated to a temperature above its melting point. Specifically, when the solder is Sn-Pb solder, the solder may be melted by heating it to a temperature in the range of 230 to 300°C.

[0107] When multiple conductive film patterns are arranged on the surface of the substrate, it is preferable that the multiple conductive film patterns are not electrically independent of each other. In other words, it is preferable that the multiple conductive film patterns are electrically connected to each other. As shown in Figure 8, the conductive film 28 may be a single continuous pattern. This allows electrons generated in the first member 22c to spread throughout the entire conductive film 28 via the wiring material 30, and a nanocrystalline film is generated uniformly over the entire surface of the conductive film 28.

[0108] [Fourth embodiment] The fourth embodiment of the present invention will be described below. In the following, descriptions of matters common to the first, second, third and fourth embodiments will be omitted in some cases.

[0109] As shown in (a), (b), and (c) of FIG. 9 and (a), (b), and (c) of FIG. 10, metal members 140 and 150 according to the fourth embodiment include a first member 22d containing a first metal and a mask material 36 overlapping the surface of the first member 22d. Water is interposed between the first member 22d and the mask material 36. The standard electrode potential of the first metal is higher than −2.00 V. An exposed portion 90 of the surface of the first member 22d that does not overlap with the mask material 36 has a predetermined pattern along the surface of the first member 22d.

[0110] 9(a), (b), and (c), the exposed portion 90 that does not overlap with the mask material 36 has a pattern of a plurality of squares that are equally spaced in a grid along the surface of the first member 22d. In other words, the mask material 36 has a mesh or lattice structure that is made up of a plurality of equally spaced parallel vertical line portions and equally spaced parallel horizontal line portions, and the exposed portion 90 of the first member 22d is located directly below the area surrounded by the vertical line portions and the horizontal line portions.

[0111] 10(a), (b), and (c), the exposed portion 90 that does not overlap with the mask material 36 has a pattern of multiple strips (rectangular) that are arranged in parallel at equal intervals along the surface of the first member 22d. In other words, the mask material 36 is made up of multiple cylindrical members that are arranged in parallel at equal intervals, and the exposed portion 90 of the first member 22d is located directly below the area between the cylindrical members. The cylindrical members may also be referred to as rod-shaped members or wires.

[0112] As shown in (c) of FIG. 9 and (c) of FIG. 10, in the light irradiation step, nanocrystalline film 25 having a predetermined pattern is formed on the surface of exposed portion 90 irradiated with light. The predetermined pattern of nanocrystalline film 25 is the same as the pattern of exposed portion 90. That is, the predetermined pattern of nanocrystalline film 25 shown in (c) of FIG. 9 is a pattern of multiple squares arranged in a grid pattern at equal intervals along the surface of first member 22d. The predetermined pattern of nanocrystalline film 25 shown in (c) of FIG. 10 is a pattern of multiple strips arranged in parallel at equal intervals along the surface of first member 22d.

[0113] The nanocrystals contained in nanocrystal film 25 include at least one of an oxide of the first metal and a hydroxide of the first metal. As shown in (c) of FIG. 9 and (c) of FIG. 10, nanocrystal film 25 may have a hydroxide film 25a covering exposed portion 90 of first member 22d and oxide rods 25b (nanorods) extending from the surface of hydroxide film 25a. Hydroxide film 25a may be a hydroxide of the first metal, and oxide rods 25b may be an oxide of the first metal. Nanocrystal film 25 may be composed only of an oxide of the first metal and a hydroxide of the first metal. Nanocrystal film 25 may be composed only of an oxide of the first metal. Nanocrystal film 25 may be composed only of a hydroxide of the first metal.

[0114] The inventors speculate that the mechanism of nanocrystal generation in the fourth embodiment is as follows. Hereinafter, the region where water is present between the first member 22d and the mask material 36, or the surface of the first member 22d located in this region, will be referred to as a "gap portion" (gap portion 94). The gap portion 94 is a portion of the surface of the first member 22d that is not irradiated with light. The exposed portion 90 irradiated with light may also be referred to as a "light-irradiated portion (90)."

[0115] In the gap 94, the metal (M) is dissolved into the water and becomes a metal ion (M n+ The reaction of the above reaction formula (1) proceeds in the gap portion 94 for the following two reasons.

[0116] The first reason is an increase in electron density in the light-irradiated portion (90). When light, which is an electromagnetic wave, is incident on the surface of the exposed portion 90 containing the first metal, an oscillating electric field is generated in the first metal. This electric field accelerates free electrons in the first metal, increasing the electron density in the light-irradiated portion (90) compared to the gap portion 94, which is not irradiated with light. As a result, a local potential difference is generated between the light-irradiated portion (90) and the gap portion 94, and the reaction of the above reaction formula (1) proceeds in the gap portion 94 to fill this difference.

[0117] The second reason is the difference in oxygen concentration between the light-irradiated portion (90) and the gap portion 94. The gap portion 94 tends to receive insufficient oxygen from the water, forming a kind of oxygen concentration cell between the light-irradiated portion (90) and the gap portion 94. As a result, the reaction represented by the above reaction formula (3) proceeds in the light-irradiated portion (90) so as to reduce the oxygen concentration. Accordingly, the reaction represented by the above reaction formula (1) proceeds in the gap portion 94.

[0118] The reaction of the above reaction formula (3) proceeds in the light irradiation part (90), and hydroxide ions (OH - ) concentration increases. - ) and the ions of the first metal (M n+ ) (the reaction of the above reaction formula (5)) proceeds in the light-irradiated portion (90). That is, a hydroxide of the first metal is formed on the surface of the light-irradiated portion (90). Subsequently, the generation of first nanocrystals by SPSC (the reactions of the above reaction formulas (7) and (8)) is promoted in the light-irradiated portion (90). Note that the reactions of the above reaction formulas (7) and (8) are reactions when the first metal M is zinc, but may occur when other first metals are used.

[0119] In addition, the hydroxide ions (OH - ) can be generated by reactions other than those shown in the above reaction formula (3). For example, as shown in the above reaction formula (9), electrons (e - ) at the interface between the light irradiated portion (90) and water. aq - ) is then converted into hydroxyl radicals (·OH) and hydrated electrons (e aq - ) reacts with hydroxide ions (OH - Therefore, hydroxide ions (OH - ) increases, the formation of the hydroxide of the first metal according to the above reaction formula (5) and the SPSC reaction according to the above reaction formulas (7) and (8) proceed preferentially on the surface of the light-irradiated portion (90).

[0120] From the viewpoint of the reactivity of the first metal with water and the solubility of the ions of the first metal in water, the standard electrode potential of the first metal is preferably higher than −2.00 V and not higher than 1.00 V, more preferably −1.80 to 0.80 V, and even more preferably −1.70 to 0.60 V.

[0121] The first metal may be, for example, at least one selected from the group consisting of copper, bismuth, tungsten, lead, tin, molybdenum, nickel, cobalt, indium, cadmium, iron, zinc, chromium, ytterbium, niobium, vanadium, manganese, zirconium, titanium, aluminum, thorium, beryllium, and europium.

[0122] The first member may contain an alloy of the first metal, or may consist solely of an alloy of the first metal. The composition of the alloy of the first metal is not particularly limited. The alloy of the first metal may be, for example, an iron alloy, a copper alloy, a zinc alloy, or the like.

[0123] From the viewpoint of nanocrystal growth, the content of the first metal in the first component is preferably 10.0 to 100.0 mass%, more preferably 15.0 to 100.0 mass%, and even more preferably 20.0 to 100.0 mass%, based on the total mass of the first component. The higher the content of the first metal in the first component, the easier it is to generate an oxide or hydroxide, and the easier it is to control the composition of the oxide or hydroxide.

[0124] The composition of the first member of the fourth embodiment may be the same as the composition of the first member of the first embodiment.

[0125] The area of the exposed portion 90 of the surface of the first member 22d is represented as S1. The area of the overlapping portion 92 of the surface of the first member 22d where the mask material 36 overlaps is represented as S2. The overlapping portion 92 is a region of the surface of the first member 22d that is not irradiated with light (non-irradiated portion). Metal ions (M n+From the viewpoint of the amount of elution of ), the uniformity of growth of nanocrystals, etc., the area ratio S2 / S1 is preferably 1 / 200 to 1 / 2, more preferably 1 / 150 to 1 / 2.5, and even more preferably 1 / 100 to 1 / 3.

[0126] The method for forming the gap 94 between the surface of the first member 22d and the mask material 36 is not particularly limited. For example, a mesh-shaped mask material 36 may be disposed on the surface of the first member 22d via a spacer having a predetermined dimension. A convex portion functioning as a spacer may be provided on a portion of the surface of the mask material 36, or only the convex portion of the surface of the mask material 36 may contact the surface of the first member 22d. As shown in (a) and (b) of FIG. 10, the gap 94 may be formed by a portion of the surface of a rod-shaped mask material 36 contacting the surface of the first member 22d. A linear mask material may be wrapped around the surface of the first member 22d via a spacer. As shown in (b) of FIG. 9, the entire surface of the first member 22d and the entire mask material 36 may be completely separated from each other. As shown in (b) of FIG. 10, a portion of the mask material 36 may contact the first member 22d.

[0127] From the viewpoints of promoting the elution of ions of the first metal and workability, the distance between the surface of the first member 22d and the mask material 36 (the width of the gap 94) is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less. However, there may be portions where the width of the gap 94 is greater than these upper limits.

[0128] The material of the mask material 36 is not particularly limited as long as it is resistant to dissolution or deterioration in water and can maintain a desired shape. The mask material 36 may be a conductive material or a non-conductive material.

[0129] The following points are common to the first, second, third and fourth embodiments.

[0130] (Light irradiation method) As shown in FIG. 1 , water 2 and a metal member 100 may be contained in a container 6a. The container 6a may include a container body 8a that contains the water 2 and the metal member 100, and a lid 10a. The container 6a does not necessarily have to include the lid 10a. The lid 10a may seal the container body 8a. Light L may be irradiated using a lamp (light source) 12. By using the lamp 12, light of a constant intensity can be irradiated onto the surface of the metal member 100. The position of the lamp 12 may be adjusted appropriately so that nanocrystals are effectively generated. When sunlight is irradiated, the lamp 12 does not need to be used. When sunlight is irradiated, the position and orientation of the container 6a may be adjusted appropriately so that sunlight is irradiated onto the surface of the metal member 100.

[0131] The metal member 100 may be oriented such that the surface onto which light is irradiated is vertical as shown in FIG. 1, or may be oriented such that the surface onto which light is irradiated is horizontal as shown in FIG.

[0132] The distance from the water surface to the light irradiation surface of the metal member 100 can be set appropriately depending on the type of metal member and water, and is not particularly limited. The distance may be, for example, 5 mm to 10 m. From the viewpoints of suppressing a decrease in effect due to light scattering and promoting the growth of nanocrystals, the distance is preferably 5 mm to 8 m, and more preferably 5 mm to 5 m.

[0133] The shape of the container body 8a is not particularly limited. The shape of the container body 8a may be a rectangular parallelepiped like the container body 8a shown in Fig. 6, or may be cylindrical like the container body 8b included in the container 6b shown in Fig. 2. The shape of the container body 8a may be appropriately selected so that light can be effectively irradiated onto the surface of the metal member 100.

[0134] The shape of the lid body 10a is not particularly limited. The shape of the lid body 10a may be a rectangular parallelepiped like the lid body 10a shown in Fig. 1, or may be a cylindrical shape like the lid body 10b shown in Fig. 2. The shape of the lid body 10a may be any shape that allows light to be effectively irradiated onto the surface of the metal member 100.

[0135] The material of the container 6a (container body 8a and lid body 10a) is not particularly limited as long as it does not block light from being irradiated onto the surface of the metal member 100. The material of the container body 8a and lid body 10a is preferably one that does not react with water. The material of the container body 8a and lid body 10a may be, for example, glass, plastic, etc.

[0136] (About the wavelength of light) The wavelength of the light used in the light irradiation step is not particularly limited. The wavelength of the light may be shorter than the wavelength of infrared light. For example, the wavelength of the light may be 1000 nm or less. In the spectrum of the light used in the light irradiation step, the wavelength at which the intensity is maximum may be 360 nm or more and less than 620 nm. The spectrum of light may be rephrased as the spectral radiant distribution of light, and the intensity may be rephrased as the spectral irradiance or spectral irradiance. In other words, in the spectral radiant distribution (spectrum) of the light used in the light irradiation step, the wavelength at which the spectral irradiance (intensity) is maximum may be 360 nm or more and less than 620 nm. The unit of the spectral irradiance (intensity) of light is, for example, W·m -2 nm -1 In the wavelength range of 360 nm or more and less than 620 nm, by adjusting the wavelength of the light irradiated onto the metal member, it is easy to control the composition of the oxides and hydroxides produced from the metal member and water. Therefore, highly crystalline nanocrystals are easily obtained. The crystallinity (degree of crystallinity) of the nanocrystals can be confirmed, for example, by X-ray diffraction (XRD) analysis. The composition of the oxides and hydroxides can be confirmed, for example, by point analysis using energy dispersive X-ray analysis (EDX). When the wavelength is 620 nm or more, it is difficult to obtain nanocrystals. When the wavelength is less than 360 nm, the nanocrystals are easily decomposed and their shape is easily distorted. The inventors speculate that the reason why nanocrystals are easily decomposed when the wavelength is less than 360 nm is as follows.

[0137] When the wavelength is less than 360 nm, if the nanocrystals are semiconductors, they may act as a photocatalyst when irradiated with light. When the nanocrystals act as a photocatalyst, photodecomposition of water occurs, producing hydrogen gas and oxygen gas, as described below. As a result, the formed oxide reverts to hydroxide, and the nanocrystals are decomposed. Furthermore, when the wavelength is less than 360 nm, the energy is easily converted to heat, which reduces energy efficiency and easily damages the metal component due to heat. To easily achieve the effects of the wavelength, the wavelength at which the intensity is greatest in the spectrum of the light used in the light irradiation step is preferably 380 to 600 nm, more preferably 400 to 580 nm. The wavelength may be adjusted appropriately within the above range in consideration of the efficiency of water radiolysis, equipment limitations, the band gap of oxides and hydroxides, and the prevention of the generation of thermal energy (heat generation) when excited electrons are relaxed.

[0138] The light source of the light irradiated onto the metal member is not particularly limited as long as it can irradiate the above-mentioned light. Examples of the light source include the sun, an LED, a xenon lamp, a mercury lamp, and a fluorescent lamp. The light irradiated onto the metal member may be, for example, sunlight or simulated sunlight. Sunlight is suitable for use because it is abundant on Earth and can be used as a renewable energy source that does not emit greenhouse gases. "Simulated sunlight" refers to light that does not use the sun as a light source and whose spectrum matches that of sunlight. Simulated sunlight can be emitted, for example, by a solar simulator using a metal halide lamp, a halogen lamp, or a xenon lamp. Simulated sunlight is generally used for the purposes of evaluating the strength of materials against ultraviolet rays, evaluating solar cells, or evaluating weather resistance. Simulated sunlight can also be suitable for use in this embodiment.

[0139] In the light irradiation step, light may be irradiated onto the interface where the surface of the metal member is in contact with water. The interface can be obtained, for example, by immersing the metal member in water or by circulating water through part or all of the metal member. In the light irradiation step, it is preferable to immerse the metal member below the water surface from the viewpoint of nanocrystal growth.

[0140] (Details of nanocrystals) As described above, the nanocrystal film formed in the light irradiation step contains the metal (e.g., the first metal) originally contained in the metal component. The nanocrystals contain at least one of an oxide and a hydroxide. The nanocrystals may be composed of an oxide and a hydroxide, or may be composed only of an oxide, or may be composed only of a hydroxide.

[0141] At least one of the oxide and hydroxide is preferably a semiconductor. That is, the nanocrystal preferably contains a semiconductor. The nanocrystal may be composed solely of a semiconductor. When the nanocrystal contains a semiconductor, the nanocrystal can be applied to semiconductor devices such as photocatalysts, luminescent materials, solar cells, quantum computers, and biosensors.

[0142] The semiconductor may include at least one of a p-type semiconductor and an n-type semiconductor. That is, the nanocrystal may include at least one of a p-type semiconductor and an n-type semiconductor. When the nanocrystal includes at least one of a p-type semiconductor and an n-type semiconductor, the conductivity of the nanocrystal (semiconductor) is improved, and the range of applications of the nanocrystal to the semiconductor device is expanded.

[0143] Oxide semiconductors (MO x ) may become a p-type or n-type semiconductor when an oxide semiconductor is doped with an impurity element or when the ratio of metal to oxygen deviates from the stoichiometric composition. When the ratio of metal to oxygen deviates from the stoichiometric composition, oxygen in the oxide semiconductor is lost, and the composition of the oxide semiconductor becomes MO. x-nAs a result, the oxide semiconductor becomes n-type. Also, when an oxide semiconductor takes in excess oxygen, the composition of the oxide semiconductor becomes MO x+n The metal atom vacancies act as holes, resulting in a p-type oxide semiconductor.

[0144] The p-type semiconductor may be at least one selected from the group consisting of copper oxide (I) (CuO), copper oxide (II) (CuO), silver oxide (I) (AgO), nickel oxide (II) (NiO), iron oxide (III) (FeO), tungsten oxide (VI) (WO), and tin oxide (II) (SnO).

[0145] The n-type semiconductor may be at least one selected from the group consisting of iron (III) oxide (Fe2O3), indium (III) oxide (In2O3), tungsten (VI) oxide (WO3), lead (II) oxide (PbO), vanadium (V) oxide (VO5), niobium (III) oxide (Nb2O3), titanium (IV) oxide (TiO2), zinc (II) oxide (ZnO), tin (IV) oxide (SnO2), aluminum (III) oxide (Al2O3), and zirconium (IV) oxide (ZrO2).

[0146] Some of the oxides mentioned above can be either p-type or n-type semiconductors. For example, iron(III) oxide (Fe2O3) is usually prone to oxygen deficiency, so iron(III) oxide behaves as an n-type semiconductor. However, when iron(III) oxide is doped with nitrogen (N), it can become p-type. In tungsten(VI) oxide (WO3), either the metal (W) or oxygen can be deficient. When the metal (W) is deficient, tungsten(VI) oxide is a p-type semiconductor. When the oxygen is deficient, tungsten(VI) oxide is an n-type semiconductor.

[0147] The shape of the nanocrystals may be at least one selected from the group consisting of needle-like, columnar, rod-like, tubular, scale-like, block-like, flower-like, starfish-like, branch-like, and convex-like shapes. The flower-like shape refers to a shape in which multiple columnar crystals extend radially from the center of the crystal. The starfish-like shape refers to a shape in which multiple columnar crystals extend approximately equally spaced from the center of the crystal in the same plane.

[0148] The maximum width (e.g., length) of the nanocrystals may be 2 nm to 10 μm, or 2 nm to 1000 nm. The maximum width of the nanocrystals implies the maximum width of an aggregate of multiple nanocrystals. The height of the nanocrystals from the surface of the metal member is not particularly limited. The nanocrystals may have a solid structure or a hollow structure. The thickness of the nanocrystal film may be 2 nm to 10 μm, or 2 nm to 1000 nm.

[0149] (About water) The water in which the metal member is immersed may include at least one selected from the group consisting of pure water, ion-exchanged water, rainwater, tap water, river water, well water, filtered water, distilled water, reverse osmosis water, spring water, spring water, dam water, and seawater. The water may also be water whose pH has been adjusted by containing at least one of an acid and a base (i.e., an aqueous solution of at least one of an acid and a base). From the viewpoints of controlling the composition of nanocrystals and productivity, pure water, ion-exchanged water, and tap water are preferred. However, naturally occurring water such as river water, well water, dam water, and seawater can also be suitably used.

[0150] The pH of the water may be 5.00 to 10.0. By setting the pH to 5.00 or higher, the formation of nanocrystals under light irradiation can be promoted. Furthermore, by setting the pH to 10.0 or lower, workability during nanocrystal film formation is improved. From the viewpoint of controlling the composition of the nanocrystals, the pH of the water is preferably 5.5 to 9.5, and more preferably 6.0 to 9.0.

[0151] The pH of the water may be measured, for example, using a pH meter manufactured by Horiba Ltd. (LAQUAact, portable pH meter / water quality meter).

[0152] The electrical conductivity of water may be 80,000 μS / cm or less. From the viewpoint of increasing the crystallinity of the nanocrystals, the electrical conductivity of water is preferably 10,000 μS / cm or less, more preferably 5,000 μS / cm or less, and even more preferably 1.0 μS / cm or less. The lower limit of the electrical conductivity of water may be, for example, 0.05 μS / cm.

[0153] The electrical conductivity of water may be measured, for example, by a pH meter manufactured by Horiba, Ltd. (LAQUAact, a portable pH meter / water quality meter).

[0154] The purity of water is not particularly limited. The purity of water refers to the mass ratio of water molecules contained in water. The purity of water may be, for example, 80.0 mass% or more based on the total mass of water. By making the purity of water 80.0 mass% or more, the influence of impurities under light irradiation can be suppressed. Examples of the influence of impurities include salt precipitation and the formation of a passivation film. From the viewpoint of controlling the composition of nanocrystals, the purity of water is preferably 85.0 mass% or more, and more preferably 90.0 mass% or more. The upper limit of the purity of water may be, for example, 100.0 mass%.

[0155] The purity of water can sometimes be controlled by its electrical conductivity. For example, when the type of solute (impurity) dissolved in water is specified and the purity of the water is within the above range, the concentration of the solute and the electrical conductivity are often proportional to each other. On the other hand, when water contains multiple solutes (impurities), it is difficult to determine the purity of the water from the measured electrical conductivity. It is preferable to control the purity of water by its electrical conductivity.

[0156] The concentration of dissolved oxygen in water is not particularly limited. From the viewpoint of promoting the growth reaction of nanocrystals by light irradiation, the concentration of dissolved oxygen in water is, for example, preferably 15 mg / L or less, more preferably 12 mg / L or less, and even more preferably 10 mg / L or less, based on the total volume of water. The lower limit of the concentration of dissolved oxygen in water may be, for example, 8.0 mg / L.

[0157] The concentration of dissolved oxygen in water may be measured, for example, using a pH meter manufactured by Horiba Ltd. (LAQUAact, portable pH meter / water quality meter).

[0158] The temperature of the water is not particularly limited, but is preferably 0 to 80°C, more preferably 2 to 75°C, and even more preferably 5 to 70°C, from the viewpoint of preventing freezing and evaporation of the water and corrosion of the metal material.

[0159] The above-described nanocrystalline film manufacturing method using SPSC allows for the easy formation of nanocrystalline films having desired patterns, compared to conventional methods. In other words, the nanocrystalline film formation process using SPSC does not require a heating step or a vacuum process, and nanocrystalline films can be formed at room temperature and atmospheric pressure. Furthermore, the nanocrystalline film formation process using SPSC does not require a high-temperature process such as a hydrothermal synthesis reaction, and nanocrystalline films can be formed without using strongly alkaline water. For these reasons, the nanocrystalline film manufacturing method using SPSC reduces the cost of the nanocrystalline film formation process and further reduces the environmental impact associated with the process.

[0160] (Applications of nanocrystalline films) The nanocrystalline film may be used as a wiring pattern, film, layer, quantum dot, or the like in an electronic circuit or electronic device. For example, the nanocrystalline film may be a transparent conductive film used in a touch panel, display, solar cell, or the like. The nanocrystalline film may be a semiconductor used in a thin film transistor, sensor, varistor, or the like. The nanocrystalline film may be an insulator used in an electronic device such as a capacitor. The nanocrystalline film may be a superconducting film used in a superconducting device or wire, or the like. The nanocrystalline film may be a piezoelectric material used in a SAW filter or sensor, or the like. The nanocrystalline film may be a photocatalyst used for photovoltaic power generation, air purification, or surface protection. The nanocrystalline film may be an anti-reflective film used in optical components, eyeglasses, UV protection glasses, or the like. The nanocrystalline film may be a surface treatment film used for surface protection.

[0161] While the preferred embodiments of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments. Various modifications of the present invention are possible without departing from the spirit of the present invention, and these modifications are also included in the present invention.

[0162] For example, by irradiating only predetermined locations on the surface of a metal member (e.g., a first member) with concentrated light (a spot of light), a nanocrystalline film having a predetermined pattern may be formed only in the locations where the light is irradiated. In the third embodiment, metal member 120 may have a second member containing a second metal instead of substrate 26, the first member and the second member may be electrically connected, and the second member may be shaped so that the entire surface of the second member has the predetermined pattern, and by irradiating the metal member with light, a pattern of a nanocrystalline film containing the first metal may be formed on the entire surface of the second member. [Example]

[0163] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples.

[0164] < reference Example 1> reference In Example 1, a metal member was prepared and subjected to a light irradiation step by the following method.

[0165] (Metal parts) Zinc with a purity of 99.8% by mass was rolled to form a plate-shaped first member. The standard electrode potential of zinc (first metal) was -0.76 V. The dimensions of the first member were 50 mm x 10 mm x 0.5 mm. Next, a second member (strip-shaped pattern) made of a thin film of platinum was formed on the surface of the first member by vacuum deposition. By the above method, a plate-shaped first member and a second member arranged on the surface of the first member were obtained. reference A metal member was obtained as in Example 1. The standard electrode potential of platinum (second metal) is 1.19 V. When depositing the platinum thin film, a stencil mask was used, and the dimensions of the deposition pattern were adjusted to 40 mm x 2 mm.

[0166] (Light irradiation process) Next, a light irradiation step was carried out by the method described below. Pure water was placed in a glass container, and the metal member was immersed in the pure water. The pH and electrical conductivity of the pure water were measured using a pH meter. The pH meter used was a LAQUAact (portable pH meter / water quality meter) manufactured by Horiba, Ltd. The pH of the pure water was 7.0, and the electrical conductivity of the pure water was 1.0 μS / cm or less. A plastic lid was placed on the container to seal it.

[0167] As shown in Figure 2, the metal member, container, and light source were arranged, and light was irradiated onto the surface of the metal member in water. That is, light was irradiated onto the surface of the metal member from a direction perpendicular to the surface of the metal member. A xenon lamp was used as the light source. A spot light source (LightningCure LC8) manufactured by Hamamatsu Photonics K.K. was used as the xenon lamp. A dedicated optical filter was attached to the xenon lamp to set the light wavelength range to 400 to 600 nm. Light was irradiated onto the surface of the metal member for 48 hours. The light output was 280 W. The light spectrum was measured using a spectroradiometer. A SOLO 2 manufactured by Gentec-EO was used as the spectroradiometer. As a result, the wavelength with the maximum intensity in the spectrum of light emitted from the xenon lamp was 360 nm or more and less than 620 nm. The wavelength with the maximum intensity in the spectrum of light emitted from the xenon lamp was approximately 493 nm. The light intensity at the light irradiation position 5 cm away from the light source was 3025 W / m. -2 The light irradiation position can be rephrased as the position on the surface of the metal member.

[0168] < reference Example 2> reference In Example 2, reference A metal member similar to that in Example 1 was prepared. Then, with the following exceptions: reference The light irradiation step was carried out in the same manner as in Example 1. reference In the light irradiation step of Example 2, the light irradiation time was 72 hours.

[0169] < reference Example 3> reference In Example 3, reference A metal member similar to that in Example 2 was prepared. Then, except for the following points, reference The light irradiation step was carried out in the same manner as in Example 2.

[0170] referenceIn the light irradiation step of Example 3, simulated sunlight was irradiated onto the surface of the metal member without using a xenon lamp as the light source. A solar simulator (HAL-320) manufactured by Asahi Spectroscopy Co., Ltd. was used as the light source for the simulated sunlight. The solar simulator used a xenon lamp. The wavelength range of the simulated sunlight emitted by the solar simulator was 350 to 1100 nm. The metal member, container, and light source were arranged as shown in Figure 2. That is, light was irradiated onto the surface of the metal member from a direction perpendicular to the surface of the metal member. The light output was 300 W. The light spectrum was measured using the spectroradiometer. As a result, the wavelength with the maximum intensity in the simulated sunlight spectrum was 360 nm or more and less than 620 nm. The wavelength with the maximum intensity in the simulated sunlight spectrum was approximately 460 nm. The light intensity at a light irradiation position 60 cm away from the light source was 1000 W / m 2 It was.

[0171] < reference Example 4> reference In Example 4, reference A metal member similar to that in Example 2 was prepared. Then, except for the following points, reference The light irradiation step was carried out in the same manner as in Example 2.

[0172] reference In the light irradiation step of Example 4, a UV lamp was used instead of a xenon lamp as the light source. The UV lamp used was a B-100AP manufactured by UVP. The surface of the metal material was irradiated with light for 72 hours. The light output was 100 W. The light spectrum was measured using the spectroradiometer. As a result, in the spectrum of light emitted from the UV lamp, the wavelength with the maximum intensity was 360 nm or more and less than 620 nm. In the spectrum of light emitted from the UV lamp, the wavelength with the maximum intensity was approximately 365 nm. The light intensity at a light irradiation position 20 cm away from the light source was 100 W / m 2 It was.

[0173] < reference Example 5> reference In Example 5, referenceA metal member similar to that in Example 2 was prepared. Then, except for the following points, reference The light irradiation step was carried out in the same manner as in Example 2.

[0174] reference In the light irradiation step of Example 5, river water was used instead of pure water. The pH and electrical conductivity of the river water were measured using the pH meter. As a result, the pH of the river water was 7.5 and the electrical conductivity of the river water was 350 μS / cm.

[0175] < reference Example 6> reference In Example 6, reference A metal member similar to that in Example 2 was prepared. Then, except for the following points, reference The light irradiation step was carried out in the same manner as in Example 2.

[0176] reference In the light irradiation step of Example 6, seawater was used instead of pure water. The pH and electrical conductivity of the seawater were measured using the pH meter. As a result, the pH of the seawater was 8.2, and the electrical conductivity of the seawater was 55,000 μS / cm.

[0177] < reference Example 7> reference In Example 7, the following metal members were prepared. reference The light irradiation step was carried out in the same manner as in Example 3.

[0178] (Metal parts) Zinc with a purity of 99.8% by mass was rolled to form a plate-shaped first member. The standard electrode potential of zinc (first metal) was -0.76 V. The dimensions of the first member were 50 mm x 10 mm x 0.5 mm. Next, a second member (strip-shaped pattern) made of a thin copper film was formed on the surface of the first member by vacuum deposition. The standard electrode potential of copper (second metal) was 0.52 V. When depositing the thin copper film, a stencil mask was used, and the dimensions of the deposition pattern were adjusted to 40 mm x 2 mm.

[0179] <Comparative Example 1> In Comparative Example 1, reference A metal member similar to that in Example 1 was prepared. Next, pure water was placed in a glass container, and the metal member was immersed in the pure water. The pH and electrical conductivity of the pure water were measured using the pH meter. As a result, the pH of the pure water was 7.0, and the electrical conductivity of the pure water was 1.0 μS / cm or less. A plastic lid was placed on the container, the container was sealed, and the container was left for 48 hours. In Comparative Example 1, the light irradiation step was not performed.

[0180] <Comparative Example 2> In Comparative Example 2, reference A metal member similar to that in Example 3 was prepared. Then, except for the following points, reference The light irradiation step was carried out in the same manner as in Example 3.

[0181] Acetone was used instead of pure water in the light irradiation step of Comparative Example 2. As the acetone, acetone (purity 99.5%) manufactured by Wako Pure Chemical Industries, Ltd. was used.

[0182] <Comparative Example 3> In Comparative Example 3, the following metal members were prepared. reference The light irradiation step was carried out in the same manner as in Example 3.

[0183] (Metal parts) Magnesium with a purity of 99.5% by mass was rolled to form a plate-shaped first member. The standard electrode potential of magnesium (first metal) was -2.36 V. The dimensions of the first member were 50 mm x 10 mm x 0.5 mm. Next, a second member (strip-shaped pattern) made of a platinum thin film was formed on the surface of the first member by vacuum deposition. The standard electrode potential of platinum (second metal) was 1.19 V. When depositing the platinum thin film, a stencil mask was used, and the dimensions of the deposition pattern were adjusted to 40 mm x 2 mm.

[0184] reference The first member, second member, water, and light irradiation conditions for each of Examples 1 to 7 and Comparative Examples 1 to 3 are shown in Table 3.

[0185] [Table 3]

[0186] Example 8 In Example 8, a metal member was prepared by the following method. reference The light irradiation step was carried out in the same manner as in Example 2.

[0187] (Metal parts) A grid mesh (pattern structure) made of copper (purity 99.9%) was used as the metal member. This grid mesh is typically used as a sample stage for a transmission electron microscope. The standard electrode potential of copper (first metal) is 0.52 V. The grid mesh had a mesh (lattice) pattern as shown in Figure 5a. The number of meshes in the grid mesh was 300. The opening dimensions of the grid mesh were 45 μm × 45 μm, and the width of the copper wires constituting the grid mesh was 38 μm.

[0188] Example 9 In Example 9, a metal member similar to that in Example 8 was prepared. reference The light irradiation step was carried out in the same manner as in Example 3.

[0189] Example 10 In Example 10, a metal member similar to that in Example 8 was prepared. reference The light irradiation step was carried out in the same manner as in Example 4.

[0190] Example 11 In Example 11, the following metal member was prepared: Then, a light irradiation step was carried out in the same manner as in Example 8.

[0191] (Metal parts) A grid mesh (pattern structure) made of nickel (purity 99.9%) was used as the metal member. This grid mesh is typically used as a sample stage for a transmission electron microscope. The standard electrode potential of nickel (first metal) is -0.26 V. The grid mesh had a mesh (lattice) pattern as shown in Figure 5 (a). The number of meshes in the grid mesh was 300. The opening dimensions of the grid mesh were 45 μm × 45 μm, and the width of the nickel wires that made up the grid mesh was 38 μm.

[0192] Example 12 In Example 12, the following metal member was prepared: Then, a light irradiation step was carried out in the same manner as in Example 8.

[0193] (Metal parts) A grid mesh made of molybdenum (purity 99.9%) was used as the metal member. This grid mesh is typically used as a sample stage for a transmission electron microscope. The standard electrode potential of molybdenum (first metal) is -0.20 V. The grid mesh had a mesh (lattice) pattern as shown in Figure 5(a). The number of meshes in the grid mesh was 300. The opening dimensions of the grid mesh were 45 μm × 45 μm, and the width of the molybdenum wires that made up the grid mesh was 38 μm.

[0194] < reference Example 13> reference In Example 13, the following metal members were prepared. reference The light irradiation step was carried out in the same manner as in Example 6.

[0195] (Metal parts) A stainless steel (SUS304) screen mesh was used as the metal member. The standard electrode potential of SUS304 (first metal) is approximately -0.50 V. The screen mesh had a mesh (lattice) pattern as shown in Fig. 5a. The number of meshes in the screen mesh was 250. Specifically, the opening dimensions of the screen mesh were 72 μm × 72 μm, and the width of the stainless steel wires that made up the screen mesh was 30 μm.

[0196] <Comparative Example 4> In Comparative Example 4, a metal member similar to that in Example 8 was prepared. Next, pure water was placed in a glass container, and the metal member was immersed in the pure water. The pH and electrical conductivity of the pure water were measured using the pH meter. As a result, the pH of the pure water was 7.0, and the electrical conductivity of the pure water was 1.0 μS / cm or less. A plastic lid was placed on the container, the container was sealed, and the container was left for 72 hours. In Comparative Example 4, the light irradiation step was not performed.

[0197] <Comparative Example 5> In Comparative Example 5, a metal member was prepared similar to that in Example 8. Then, a light irradiation step was carried out in the same manner as in Example 8, except for the following points.

[0198] Acetone was used instead of pure water in the light irradiation step of Comparative Example 5. As the acetone, acetone (purity 99.5%) manufactured by Wako Pure Chemical Industries, Ltd. was used.

[0199] Example 8 12, Reference example The first member, water, and light irradiation conditions for each of Comparative Examples 13, 4, and 5 are shown in Table 4.

[0200] [Table 4]

[0201] < reference Example 14> reference In Example 14, a metal member was prepared by the following method. referenceThe light irradiation step was carried out in the same manner as in Example 2.

[0202] (First member) Zinc with a purity of 99.8% by mass was rolled to form a plate-shaped first member. The standard electrode potential of zinc (first metal) was −0.76 V. The dimensions of the first member were 70 mm×50 mm×0.5 mm.

[0203] (Substrate and conductive film) A conductive film (thin film) made of gold was formed on the surface of a plate-shaped substrate by vacuum deposition. A PET plate was used as the substrate. The thickness of the substrate was 50 μm. A stencil mask was used to deposit the gold thin film, forming a thin film with the pattern shown in Figure 8. The line width of the pattern was adjusted to 3.0 mm.

[0204] (Electrical connection) As shown in FIG. 6, one end of the copper wire was wound around the first member, and the other end of the copper wire was wound around the substrate. The fixing position of the copper wire on the substrate was adjusted so that the copper wire came into direct contact with the conductive film, thereby electrically connecting the first member and the conductive film formed on the surface of the substrate. By the above method, a device comprising the first member, the substrate, and the conductive film was obtained. reference This resulted in the metal member of Example 14. The copper wire had a width of 0.5 mm and a purity of 99.9 mass %.

[0205] < reference Example 15> reference In Example 15, a metal member was prepared by the following method. reference The light irradiation step was carried out in the same manner as in Example 2.

[0206] (First member) Zinc with a purity of 99.8% by mass was rolled to form a plate-shaped first member. The standard electrode potential of zinc (first metal) was −0.76 V. The dimensions of the first member were 70 mm×50 mm×0.5 mm.

[0207] (Substrate and conductive film) A conductive film (thin film) made of indium tin oxide (ITO) was formed on the entire surface of a plate-shaped substrate by sputtering. The substrate was a soda-lime glass plate with a thickness of 50 μm. The conductive film was then processed into the pattern shown in Figure 8 by photolithography. The line width of the pattern was adjusted to 3.0 mm.

[0208] (Electrical connection) As shown in FIG. 6, one end of the copper wire was wound around the first member, and the other end of the copper wire was wound around the substrate. The fixing position of the copper wire on the substrate was adjusted so that the copper wire came into direct contact with the conductive film, thereby electrically connecting the first member and the conductive film formed on the surface of the substrate. By the above method, a device comprising the first member, the substrate, and the conductive film was obtained. reference This resulted in the metal member of Example 15. The copper wire had a width of 0.5 mm and a purity of 99.9 mass %.

[0209] < reference Example 16> reference In Example 16, reference A metal member similar to that in Example 15 was prepared. reference The light irradiation step was carried out in the same manner as in Example 3.

[0210] < reference Example 17> reference In Example 17, reference A metal member similar to that in Example 15 was prepared. reference The light irradiation step was carried out in the same manner as in Example 4.

[0211] < reference Example 18> reference In Example 18, a metal member was prepared by the following method. reference The light irradiation step was carried out in the same manner as in Example 15.

[0212] (First member) Iron with a purity of 99.8% by mass was rolled to form a plate-shaped first member. The standard electrode potential of iron (first metal) was −0.44 V. The dimensions of the first member were 70 mm×50 mm×0.5 mm.

[0213] (Substrate and conductive film) A conductive film (thin film) made of indium tin oxide (ITO) was formed on the entire surface of a plate-shaped substrate by sputtering. The substrate was a soda-lime glass plate with a thickness of 50 μm. The conductive film was then processed into the pattern shown in Figure 8 by photolithography. The line width of the pattern was adjusted to 3.0 mm.

[0214] (Electrical connection) As shown in FIG. 6, one end of the copper wire was wound around the first member, and the other end of the copper wire was wound around the substrate. The fixing position of the copper wire on the substrate was adjusted so that the copper wire came into direct contact with the conductive film, thereby electrically connecting the first member and the conductive film formed on the surface of the substrate. By the above method, a device comprising the first member, the substrate, and the conductive film was obtained. reference This resulted in the metal member of Example 18. The copper wire had a wire width of 0.5 mm and a purity of 99.9 mass %.

[0215] < reference Example 19> reference In Example 19, reference A metal member similar to that in Example 18 was prepared. reference The light irradiation step was carried out in the same manner as in Example 5.

[0216] <Comparative Example 6> In Comparative Example 6, reference A metal member similar to that in Example 15 was prepared. Next, pure water was placed in a glass container, and the metal member was immersed in the pure water. The pH and electrical conductivity of the pure water were measured using the pH meter. As a result, the pH of the pure water was 7.0, and the electrical conductivity of the pure water was 1.0 μS / cm or less. A plastic lid was placed on the container, the container was sealed, and the container was left for 72 hours. In Comparative Example 6, the light irradiation step was not performed.

[0217] <Comparative Example 7> In Comparative Example 7, reference The same first member, substrate, and conductive film as in Example 15 were prepared. reference The light irradiation step was carried out in the same manner as in Example 17.

[0218] In the light irradiation step of Comparative Example 7, the first member was not electrically connected to the conductive film formed on the surface of the base material. That is, the first member and the base material, which were separated from each other and not connected by a copper wire, were immersed in pure water.

[0219] <Comparative Example 8> In Comparative Example 8, reference A metal member similar to that of Example 15 was prepared. Then, except for the following points, reference The light irradiation step was carried out in the same manner as in Example 15.

[0220] Acetone was used instead of pure water in the light irradiation step of Comparative Example 8. As the acetone, acetone (purity 99.5%) manufactured by Wako Pure Chemical Industries, Ltd. was used.

[0221] reference The first members, substrates, conductive films, wiring materials, water, and light irradiation conditions for each of Examples 14 to 19 and Comparative Examples 6 to 8 are shown in Table 5.

[0222] [Table 5]

[0223] < reference Example 20> reference In Example 20, a metal member was prepared by the following method. reference The light irradiation step was carried out in the same manner as in Example 2.

[0224] (Metal parts) Copper with a purity of 99.5% by mass was rolled to form a plate-shaped first member. The standard electrode potential of copper (first metal) was 0.52 V. The dimensions of the first member were 50 mm x 10 mm x 0.5 mm.

[0225] 9(a), the copper grid mesh used in Example 8 was placed on the surface of the first member as a mask material. The grid mesh was fixed to the surface of the first member via a spacer so that the distance (gap) between the surface of the first member and the surface of the grid mesh was 5 μm.

[0226] < reference Example 21> reference In Example 21, reference A metal member similar to that in Example 20 was prepared. reference The light irradiation step was carried out in the same manner as in Example 3.

[0227] < reference Example 22> reference In Example 22, reference A metal member similar to that in Example 20 was prepared. reference The light irradiation step was carried out in the same manner as in Example 4.

[0228] < reference Example 23> reference In Example 23, reference A metal member similar to that in Example 20 was prepared. reference The light irradiation step was carried out in the same manner as in Example 13.

[0229] < reference Example 24> reference In Example 23, the following metal members were prepared. reference The light irradiation step was carried out in the same manner as in Example 20.

[0230] (Metal parts) referenceA first member similar to that of Example 20 was prepared. A copper wire (linear mask material) was wound around the surface of the first member while in contact with it. At this time, the pitch of the copper wire on the surface of the first member was adjusted to 2 mm. The copper wire had a line width of 0.1 mm and a purity of 99.9% by mass. The cross section of the copper wire was nearly circular, and since the copper wire was in line contact with the surface of the first member, there was a gap between the copper wire and the surface of the first member, through which water was present.

[0231] < reference Example 25> reference In Example 25, the following metal members were prepared. reference The light irradiation step was carried out in the same manner as in Example 20.

[0232] (Metal parts) Iron with a purity of 99.5% by mass was rolled to form a plate-shaped first member. The standard electrode potential of iron (first metal) was −0.44 V. The dimensions of the first member were 50 mm×10 mm×0.5 mm.

[0233] Next, reference A copper grid mesh (mask material) was overlaid on the surface of the first member in the same manner as in Example 20. At this time, the grid mesh was fixed to the surface of the first member via a spacer so that the distance (gap) between the surface of the first member and the surface of the grid mesh was 5 μm.

[0234] < reference Example 26> reference In Example 26, the following metal members were prepared. reference The light irradiation step was carried out in the same manner as in Example 24.

[0235] (Metal parts) Zinc with a purity of 99.8% by mass was rolled to form a plate-shaped first member. The standard electrode potential of zinc (first metal) was −0.76 V. The dimensions of the first member were 50 mm×10 mm×0.5 mm.

[0236] Next, referenceAs in Example 24, a copper wire (linear mask material) was wound around the surface of the first member while in contact with it. At this time, the pitch of the copper wire on the surface of the first member was adjusted to 2 mm. The copper wire had a line width of 0.1 mm and a purity of 99.9% by mass. The cross section of the copper wire was nearly circular, and since the copper wire was in line contact with the surface of the first member, there was a gap between the copper wire and the surface of the first member, through which water was present.

[0237] <Comparative Example 9> In Comparative Example 9, reference A metal member similar to that of Example 20 was prepared. Next, pure water was placed in a glass container, and the metal member was immersed in the pure water. The pH and electrical conductivity of the pure water were measured using the pH meter. As a result, the pH of the pure water was 7.0, and the electrical conductivity of the pure water was 1.0 μS / cm or less. A plastic lid was placed on the container, the container was sealed, and the container was left for 72 hours. In Comparative Example 9, the light irradiation step was not performed.

[0238] <Comparative Example 10> In Comparative Example 10, reference A metal member similar to that of Example 20 was prepared. Then, except for the following points, reference The light irradiation step was carried out in the same manner as in Example 20.

[0239] Acetone was used instead of pure water in the light irradiation step of Comparative Example 10. As the acetone, acetone (purity 99.5%) manufactured by Wako Pure Chemical Industries, Ltd. was used.

[0240] <Comparative Example 11> In Comparative Example 11, reference A first member similar to that of Example 20 was prepared. Then, the following was performed except for the following points: reference The light irradiation step was carried out in the same manner as in Example 20.

[0241] In Comparative Example 11, no mask material was used.

[0242] <Comparative Example 12> In Comparative Example 12, referenceA metal member similar to that of Example 20 was prepared. Then, except for the following points, reference The light irradiation step was carried out in the same manner as in Example 20.

[0243] In the light irradiation step of Comparative Example 12, an infrared lamp was used instead of a xenon lamp. As the infrared lamp, a SICCA 250 W 240 V infrared lamp manufactured by OSRAM Corporation was used. The wavelength of the light from the infrared lamp was greater than 1000 nm. The light spectrum was measured with the above-mentioned spectroradiometer. As a result, in the light spectrum of the infrared lamp, the wavelength at which the intensity was maximum was 620 nm or more. In the light spectrum of the infrared lamp, the wavelength at which the intensity was maximum was approximately 1100 nm. The light intensity at the light irradiation position was an average of 35 W / m 2 It was.

[0244] <Comparative Example 13> In Comparative Example 13, reference A first member and a mask material similar to those in Example 20 were prepared. Then, except for the following points, reference The light irradiation step was carried out in the same manner as in Example 20.

[0245] In Comparative Example 13, no distance was provided between the first member and the mask material, and the mask material was directly attached to the surface of the first member, i.e., no gap was provided between the mask material and the surface of the first member.

[0246] reference Table 6 shows the first member, mask material, water, and light irradiation conditions for each of Examples 20 to 26 and Comparative Examples 9 to 13.

[0247] [Table 6]

[0248] <Evaluation> (crystalline phase) reference Example 1 7, Examples 8 to 12, Reference Examples 13 toThe surfaces of the metal members of Example 26 and Comparative Examples 1 to 12 after the light irradiation step were individually analyzed by X-ray diffraction (XRD) to identify the main crystalline phases formed on the surfaces of each metal member. In Comparative Examples 1, 4, 6, and 9, the metal members were held in water for the above-mentioned time, and then the surfaces of each metal member were analyzed by X-ray diffraction (XRD) to identify the main crystalline phases. In the XRD analysis, an X-ray diffractometer was used to irradiate the surface of each member with Cu-Kα rays. The measurement conditions for the XRD analysis were as follows. The X-ray diffractometer used was an ATG-G (powder X-ray diffractometer) manufactured by Rigaku Corporation. The compositions of the main crystalline phases detected in each metal member and the locations where the crystalline phases were detected are shown in Tables 7 to 10. Output: 50kV-300mA Scan speed: 4.0° / min Measurement mode: θ-2θ Diffraction angle: 10~60°

[0249] (presence and shape of nanocrystals) reference Example 1 7, Examples 8 to 12, Reference Examples 13 to The surfaces of the metal members of Example 26 and Comparative Examples 1 to 12 after the light irradiation step were individually observed using a scanning electron microscope to check for the presence or absence of nanocrystals. A JSM-7001F manufactured by JEOL Ltd. was used as the scanning electron microscope. In Comparative Examples 1, 4, 6, and 9, the metal members were held in water for the above-mentioned time, and then the surfaces of each member were observed using the scanning electron microscope to check for the presence or absence of nanocrystals. Furthermore, if nanocrystals were formed, the shape of the nanocrystals was evaluated. Furthermore, elemental analysis of the microstructures formed on the surfaces of each member was performed by point analysis using an energy dispersive X-ray analyzer (EDX) attached to the scanning electron microscope.

[0250] referenceNumerous rod-shaped and flower-shaped nanocrystals were observed on the surfaces of the metal members of Examples 1 to 7, as shown in Figures 11 and 12. In particular, a nanocrystalline film pattern consisting of numerous nanocrystals was formed over the entire surface of the second member. On the other hand, the number of nanocrystals formed on the surface of the first member was significantly smaller than that on the surface of the second member. In other words, no nanocrystalline film was formed on the surface of the first member itself. XRD and EDX analysis revealed that the nanocrystals on the surface of the second member were mainly ZnO, with Zn(OH)2 also present in some parts of the surface of the second member. The nanocrystals formed on the surface of the first member were mainly ZnO and Zn(OH)2. reference In Examples 1 to 7, the first and second members were electrically connected, and the difference in standard electrode potential between them was large, which is thought to have promoted the dissolution of zinc in the first member (the reaction of the above reaction formula (1)) and the formation of Zn(OH)2 in the second member, followed by the generation and growth of ZnO (nanocrystals) by SPSC. The inventors believe that the reason why the amount of nanocrystals generated in the first member was small is as follows. reference It is believed that ZnO due to SPSC is significantly formed on the surface of the first member in the configurations of the metal members of Examples 1 to 7. However, the electrons (e - ) flowed into the second component side, the reactions shown in the above reaction formulas (3) or (9) to (10) became difficult to occur on the surface of the first component, and the hydroxide ions (OH - ) concentration is thought to have decreased.

[0251] No nanocrystalline film having a predetermined pattern was formed on the surface of the metal member in Comparative Examples 1 and 2. In Comparative Examples 1 and 2, the hydroxide shown in Table 7 uniformly coated the surface of the first member.

[0252] In Comparative Example 3, a large amount of non-nanocrystalline Mg(OH)2 was formed on the surface of the first member, and no nanocrystals were observed on the surface of the second member. In other words, no nanocrystalline film with a predetermined pattern was formed on the surface of the metal member in Comparative Example 3. The standard electrode potential of magnesium is low at -2.36 V, which suggests that a direct reaction between magnesium and water proceeded. Furthermore, a small amount of MgO was thermodynamically formed on the surface of the first member.

[0253] [Table 7]

[0254] Example 8 ~12 and reference examples On the surface of the metal member (pattern structure) of Example 13, numerous rod-shaped and flower-shaped nanocrystals were observed, as shown in Figures 11 and 12. ~12 and reference examples In the case of 13, a nanocrystal film with a pattern similar to that of the patterned structure was formed on the surface of the patterned structure. XRD and EDX analyses revealed that the nanocrystals on the surface of the metal components were mainly oxides of the metallic materials that constituted each metal component. It is believed that the formation of hydroxides shown in the above reaction formulas (1) to (5) and the formation and growth of nanocrystals by SPSC shown in the above reaction formulas (7) and (8) occurred on the surface of each metal component.

[0255] No nanocrystals were formed on the surface of the metal members in Comparative Examples 4 and 5. In Comparative Examples 4 and 5, copper hydroxide (Cu(OH)2) and copper oxide (Cu2O) shown in Table 8 uniformly covered the surface of the metal members.

[0256] [Table 8]

[0257] reference On the surfaces of the metal materials of Examples 14 to 19, numerous rod-shaped and flower-shaped nanocrystals were observed, as shown in FIGS. referenceIn all of Examples 14 to 19, nanocrystals were formed only on the surface of the conductive film, and no nanocrystals were observed on the surface of the substrate itself where the conductive film was not formed. reference In Examples 14 to 19, a nanocrystal film having a pattern similar to that of the conductive film was formed on the surface of the conductive film. XRD and EDX analyses revealed that the nanocrystals on the surface of the conductive film were mainly oxides of the metal material constituting the first member. reference In Examples 14 to 19, the first member and the conductive film were electrically connected, which is thought to have promoted the dissolution of the first metal in the first member (the reaction of the above reaction formula (1)), the formation of hydroxide on the conductive film, and the subsequent generation and growth of oxide (nanocrystals) by SPSC. The inventors believe that the reason nanocrystals were not generated on the surface of the substrate itself, where the conductive film was not formed, is as follows. reference The substrates used in Examples 14 to 19 had high volume resistivities and were essentially insulators. Therefore, the electrons (e - ) does not spread throughout the entire substrate, and the reaction shown in the above reaction formula (3) or (9) to (10) occurs only on the conductive film, and the accompanying generation and growth of nanocrystals by SPSC also occurs only on the conductive film.

[0258] In each of Comparative Examples 6 to 8, no nanocrystals were formed on the surface of the substrate and conductive film.

[0259] [Table 9]

[0260] reference As shown in Figures 11 and 12, numerous rod-shaped and flower-shaped nanocrystals were observed on the surface of the first member in Examples 20 to 26. The numerous nanocrystals were selectively formed in the light-irradiated areas of the surface of the first member, and were not formed in the non-irradiated areas (gap areas). The surface of the first member located in the gap areas maintained its metallic state. In other words, referenceIn Examples 20 to 26, a nanocrystal film having the same pattern as the irradiated area was formed on the surface of the irradiated area. XRD and EDX analyses revealed that the nanocrystals formed in the irradiated area were mainly oxides of the metal material constituting the first member. reference In Examples 20 to 26, the first component has a region (gap) where light is not irradiated and water is present in a part of its surface. This causes a difference in electron density or a difference in oxygen concentration in water between the light irradiated portion and the gap, which in turn causes the first metal to dissolve out of the gap (the reaction of the above-mentioned reaction formula (1)) and the hydroxide ions (OH - ) concentration increased, which is thought to have promoted the formation of hydroxides of the first metal in the irradiated area and the subsequent generation of first nanocrystals by SPSC.

[0261] No nanocrystals were formed on the surface of each of the metal members of Comparative Examples 9 and 10.

[0262] In Comparative Example 11, no mask material was used, and therefore the nanocrystals shown in Table 10 were formed on the entire surface of the metal member. In other words, the nanocrystal film formed on the surface of the metal member in Comparative Example 11 was not patterned.

[0263] Nanocrystals were also not formed on the surface of the metal member of Comparative Example 12. It is believed that in Comparative Example 12, the reaction for producing nanocrystals did not proceed because the irradiated light was infrared light.

[0264] Nanocrystals shown in Table 10 were formed on the irradiated portion of the surface of the metal member of Comparative Example 13. On the other hand, nanocrystals were not formed on the non-irradiated portion, but a film consisting of hydroxides and oxides (CuO) shown in Table 10 was uniformly coated on the non-irradiated portion. In Comparative Example 13, a portion of the film formed on the irradiated portion was continuous with the film formed on the non-irradiated portion. In other words, in Comparative Example 13, a nanocrystal film pattern independent of the film on the non-irradiated portion could not be selectively formed only on the irradiated portion. In Comparative Example 13, the first member and the mask material were in contact, and almost no gaps were formed. Therefore, it is believed that the SPSC reaction proceeded independently in the irradiated portion of Comparative Example 13 using the same mechanism as Comparative Example 11. On the other hand, in the non-irradiated areas, water entered the small gap between the first member and the mask material, and it is thought that the metal ionization and hydroxide formation shown in the above reaction formulas (1) to (5) occurred.Furthermore, since photoinduced tip growth by SPSC did not occur in the non-irradiated areas, it is thought that non-nanocrystalline hydroxides and oxides uniformly covered the non-irradiated areas.The results of Comparative Example 13 showed that in order to pattern a nanocrystalline film using a mask material, it is necessary to secure a certain amount of gap (gap portion) in the non-irradiated areas.

[0265] [Table 10] [Industrial Applicability]

[0266] According to the present invention, it is possible to easily form a nanocrystalline film containing at least one of a metal oxide and a metal hydroxide and having a desired pattern, and this patterning method can be used to manufacture semiconductor devices, optical devices, etc. [Explanation of symbols]

[0267] 2...water, 6a, 6b...container, 8a, 8b...container body, 10a, 10b...lid, 12...lamp (light source), 22a, 22c, 22d...first member, 22b...pattern structure, 24...second member, 25...nanocrystalline film, 25a...hydroxide film, 25b...oxide rod (nanorod), 26...substrate, 28...conductive film, 30...wiring material, 32...metal wire, 34...brazing material, 36...mask material, 90...exposed portion, 92...overlapping portion, 94...gap, 100, 110, 120, 130, 140...metal member, L...light, S1...area of exposed portion, S2...area of overlapping portion.

Claims

1. By irradiating the surface of a metal member immersed in water with light, a nanocrystalline film (excluding the active material in lithium-ion batteries) having a predetermined pattern is formed. a light irradiation step of forming a metal film on the surface of the metal member; the nanocrystals in the nanocrystalline film comprise an oxide; the oxide is an oxide of a first metal derived from the metal member, the metal member has a first member containing the first metal, the standard electrode potential of the first metal is greater than −2.00 V; the first member is a pattern structure having the predetermined pattern, In the light irradiation step, the nanocrystal film is formed on the surface of the pattern structure, and the nanocrystal film has the same predetermined pattern as the pattern structure; the first metal is at least one selected from the group consisting of bismuth, tungsten, lead, tin, molybdenum, cobalt, indium, cadmium, zinc, chromium, ytterbium, niobium, vanadium, manganese, zirconium, thorium, beryllium, and europium; Methods for producing nanocrystalline films (excluding active materials in lithium-ion batteries).

2. By irradiating the surface of a metal member immersed in water with light, a nanocrystalline film (excluding the active material in lithium-ion batteries) having a predetermined pattern is formed. a light irradiation step of forming a metal film on the surface of the metal member; the nanocrystals in the nanocrystalline film comprise hydroxide; the hydroxide is a hydroxide of a first metal derived from the metal member, the metal member has a first member containing the first metal, the standard electrode potential of the first metal is greater than −2.00 V; the first member is a pattern structure having the predetermined pattern, In the light irradiation step, the nanocrystal film is formed on the surface of the pattern structure, and the nanocrystal film has the same predetermined pattern as the pattern structure. Methods for producing nanocrystalline films (excluding active materials in lithium-ion batteries).

3. The metal member comprises an alloy. The method for producing the nanocrystalline film according to claim 1 or 2.

4. The pattern structure has at least one of a mesh structure and a lattice structure. The method for producing the nanocrystalline film according to any one of claims 1 to 3.

5. The light is sunlight or simulated sunlight. The method for producing the nanocrystalline film according to any one of claims 1 to 4.

6. In the spectrum of the light, the wavelength at which the intensity is maximum is 360 nm or more and less than 620 nm. The method for producing the nanocrystalline film according to any one of claims 1 to 5.

7. The water is at least one selected from the group consisting of pure water, ion-exchanged water, rainwater, tap water, river water, well water, filtered water, distilled water, reverse osmosis water, spring water, spring water, dam water, and seawater. The method for producing the nanocrystalline film according to any one of claims 1 to 6.

8. The pH of the water is 5.00 to 10.

0. The method for producing the nanocrystalline film according to any one of claims 1 to 7.

9. The electrical conductivity of the water is 0.05 to 1.0 μS / cm. The method for producing the nanocrystalline film according to any one of claims 1 to 8.

10. The nanocrystals have at least one shape selected from the group consisting of needle-like, column-like, rod-like, tubular, scale-like, lump-like, flower-like, starfish-like, branch-like, and convex-like shapes. The method for producing the nanocrystalline film according to any one of claims 1 to 9.

11. the first metal is at least one selected from the group consisting of copper, bismuth, tungsten, lead, tin, molybdenum, nickel, cobalt, indium, cadmium, iron, zinc, chromium, ytterbium, niobium, vanadium, manganese, zirconium, titanium, aluminum, thorium, beryllium, and europium; The method for producing the nanocrystalline film according to claim 2 .

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