Method of manufacturing three-dimensional porous composite metal compound structures

Abstract

The present disclosure relates to a method for manufacturing a three-dimensional porous composite metal compound structure, comprising: (a) a step of manufacturing a three-dimensional porous photoresist mold by irradiating a photoresist in contact with a phase mask of a porous structure with near-field light; (b) a step of manufacturing a first structure by depositing a composite metal compound on the surface of the photoresist mold using atomic layer deposition; (c) a step of manufacturing a second structure by removing the photoresist mold contained in the first structure; and (d) a step of manufacturing a three-dimensional porous composite metal compound structure by annealing the second structure.

Description

Technology Field

[0001] The present disclosure relates to a method for manufacturing a three-dimensional porous composite metal compound structure. Background Technology

[0002] A complex metal compound containing at least one metal element belonging to groups 14 to 16 of the periodic table, exemplarily represented as A2B3 (A=Bi or Sb, B=Te or Se), has a wide range of applications as solar cells, photosensors, thermoelectric devices, and photoelectrochemical devices due to its excellent electrical, optical, and thermal properties.

[0003] In particular, three-dimensional composite metal compound structures can realize unique and excellent material properties because they have a large surface area, uniform dispersion, and continuous electrical and thermal conduction paths that surpass conventional two-dimensional composite metal compounds, so research to manufacture them is actively underway.

[0004] For example, a method has been developed to fabricate a three-dimensional composite metal compound structure by stacking composite metal compounds using 2D lithography techniques such as electron beam lithography and photolithography, and then selectively removing a sacrificial layer, but there are problems such as complex processes, low throughput, high costs, and long processing times.

[0005] In addition, methods such as colloidal self-assembly, direct ink writing (DIW), interference lithography, and two-photon lithography have been proposed; however, they face difficulties in practical application due to limitations such as defect generation, low reproducibility, slow process speed, and low resolution. The problem to be solved

[0006] The purpose of the present disclosure is to solve the problems of the prior art described above by providing a method for stably manufacturing a continuous and aligned three-dimensional porous composite metal compound structure over a large area.

[0007] Another objective of the present disclosure is to provide a method for manufacturing a high-quality three-dimensional porous composite metal compound structure by preventing structural collapse of the composite metal compound structure and suppressing changes in the physicochemical properties of the composite metal compound.

[0008] Another object of the present disclosure is to provide a three-dimensional porous composite metal compound structure that includes pores of uniform size, has high crystallinity, and has an increased content of metal elements. means of solving the problem

[0009] A method for manufacturing a three-dimensional porous composite metal compound structure according to the present disclosure comprises: (a) a step of manufacturing a three-dimensional porous photoresist mold by irradiating a photoresist in contact with a phase mask of the porous structure with near-field light; (b) a step of manufacturing a first structure by depositing a composite metal compound on the surface of the photoresist mold using atomic layer deposition; (c) a step of manufacturing a second structure by removing the photoresist mold contained in the first structure; and (d) a step of manufacturing a three-dimensional porous composite metal compound structure by annealing the second structure.

[0010] In one example, the annealing may be performed under temperature conditions of 50 to 400°C.

[0011] In one example, the surface of the photoresist mold may not be exposed on the outermost side of the first structure.

[0012] In one example, the near-field light may be a laser in the ultraviolet or visible light wavelength band.

[0013] In one example, the near-field light may be an ultraviolet laser having a wavelength band of 200 to 400 nm.

[0014] In one example, the composite metal compound may contain at least one metal element belonging to groups 14 to 16 of the periodic table.

[0015] In one example, the composite metal compound may include one or more selected from the group comprising Bi2S3, Bi2Se3, Bi2Te3, Sb2Se3, Sb2Te3, Cu2Se, Cu2Te, Ag2Se, Ag2Te, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbS, PbSe, PbTe, AgBiS2, AgBiSe2, AgBiTe2, AgSbS2, AgSbSe2, AgSbTe2, CuBiS2, CuBiSe2, CuBiTe2, CuSbS2, CuSbSe2, and CuSbTe2.

[0016] In one example, step (c) above may be to remove a photoresist template contained in the first structure using an organic solvent.

[0017] In one example, the photoresist mold may have a three-dimensional porous structure including a plurality of pores spaced apart from each other.

[0018] In one example, the photoresist may include a phenolic photoresist.

[0019] The present disclosure includes a three-dimensional porous composite metal compound structure manufactured by the method described above.

[0020] In one example, the three-dimensional porous composite metal compound structure comprises a plurality of mutually spaced pores; and a composite metal compound framework located between the adjacent pores; and the mutually spaced plurality of pores may be connected to each other to form a three-dimensional porous network.

[0021] In one example, Sb 3d of the three-dimensional porous composite metal compound structure 5 / 2 In the XPS spectrum, the intensity of the first peak (I1) occurring at a binding energy of 530±0.5 eV may be greater than the intensity of the second peak (I2) occurring at a binding energy of 531±0.5 eV.

[0022] The nitrogen oxide detection sensor according to the present disclosure comprises a three-dimensional porous composite metal compound structure manufactured by the method described above. Effects of the invention

[0023] The method for manufacturing a three-dimensional porous composite metal compound structure according to the present disclosure can stably manufacture a continuous and aligned three-dimensional porous composite metal compound structure over a large area.

[0024] In addition, the quality of the three-dimensional porous composite metal compound structure produced can be significantly improved by preventing the structure of the composite metal compound structure from collapsing during the manufacturing process and suppressing changes in the physicochemical properties of the composite metal compound.

[0025] Furthermore, the three-dimensional porous composite metal compound structure has high crystallinity, and can lower the proportion of impurities such as carbon and oxygen within the structure and increase the proportion of metal elements. Brief explanation of the drawing

[0026] Figure 1 is a scanning electron microscope image of the front view of the first structure when a three-dimensional porous composite metal compound structure is manufactured by the method according to Comparative Example 1. Figure 2 is a scanning electron microscope image of a cross-sectional view of the first structure when a three-dimensional porous composite metal compound structure is manufactured by the method according to Comparative Example 1. Figure 3 is a scanning electron microscope image showing the cross-sectional view and top view of a three-dimensional porous composite metal compound structure prepared by the method according to Comparative Example 1. Figure 4 is a scanning electron microscope image showing the top view and cross-sectional view of a three-dimensional porous composite metal compound structure prepared by the method according to Comparative Example 1. Figure 5 is a scanning electron microscope image and an EDS mapping image showing the elemental distribution of a three-dimensional porous composite metal compound prepared by the method according to Comparative Example 1. FIG. 6 is a scanning electron microscope image showing the cross-sections of a photoresist template (3D NR polymeric template), a first structure (Sb2Se3-coated 3D NR), and a second structure (3D thin-shell Sb2Se3) when preparing a three-dimensional porous composite metal compound by the method according to Example 1. FIG. 7 shows photographs, XRD spectra, and cross-sectional scanning electron microscope images of three-dimensional porous composite metal compound structures according to Comparative Example 2 (Before annealing), Example 1 (Annealed at 150℃_30 min), Example 2 (Annealed at 300℃_30 min), and Example 3 (Annealed at 450℃_30 min). FIG. 8 shows the grazing incident wide angle X-ray scattering (GIWAXS) images of three-dimensional porous composite metal compound structures according to (a) Comparative Example 2 (before annealing), (b) Example 1 (annealed at 150°C), and (c) Example 2 (annealed at 300°C), respectively. FIG. 9 is a GIWAXS XRD spectrum for (a) the in-plane direction and (b) the out-of-plane direction of a three-dimensional porous composite metal compound structure according to Comparative Example 2 (Before annealing), Example 1 (Annealed at 150°C), Example 2 (Annealed at 300°C), and Example 3 (Annealed at 450°C), respectively. FIG. 10 is a scanning electron microscope image showing the cross-section of a three-dimensional porous composite metal compound structure according to Comparative Example 2 (Before annealing), Example 1 (Annealed at 150°C), Example 2 (Annealed at 300°C), and Example 3 (Annealed at 450°C), respectively. FIG. 11 is the Raman spectrum of a photoresist template (3D NR), a first structure (Sb2Se3-coated 3D NR), and a three-dimensional porous composite metal compound structure (3D Sb2Se3) when manufacturing a three-dimensional porous composite metal compound structure by the method according to Example 1. Figure 12 shows the XPS spectra of Sb 3d and Se 3d of three-dimensional porous composite metal compound structures according to Comparative Example 2 (Before annealing), Example 1 (Annealed at 150°C), Example 2 (Annealed at 300°C), and Example 3 (Annealed at 450°C), respectively. FIG. 13(a) is a graph evaluating (a) the NO2 gas response characteristics of the three-dimensional porous composite metal compound structures according to Comparative Example 2 (3D Sb2Se3_0), Example 1 (3D Sb2Se3_150), Example 2 (3D Sb2Se3_300), and Example 3 (3D Sb2Se3_450), and (b) the response characteristics of the three-dimensional porous composite metal compound structure according to Example 2 at different NO2 gas concentrations. FIG. 14 is a graph evaluating the response characteristics of a three-dimensional porous composite metal compound structure according to Example 2 after (a) repeated exposure to NO₂ gas at a concentration of 100 ppm 10 times and (b) exposure to NO₂ gas at a concentration of 100 ppm for 3 months. Figure 15 is a graph showing the response characteristics of a three-dimensional porous composite metal compound structure according to Example 2, measured according to different types of gas. Figure 16 is a graph comparing the reactivity of various composite metal compound-based NO2 gas sensors. Specific details for implementing the invention

[0027] The terms used in this specification have been selected to be as widely used as possible, taking into account the function of this disclosure; however, these terms may vary depending on the intent of those skilled in the relevant field, case law, the emergence of new technologies, etc. Unless otherwise defined, technical and scientific terms used may have the meaning commonly understood by those skilled in the art to which this invention pertains.

[0028] In this specification and the appended claims, terms such as “comprising” or “having” mean that the features or components described in the specification exist, and unless specifically limited, do not preclude the possibility that one or more other features or components may be added.

[0029] In this specification and the appended claims, when a part such as a film (layer), region, or component is described as being on or above another part, it includes not only cases where it is directly above in contact with the other part, but also cases where another film (layer), other region, or other component is interposed therein.

[0030] In this specification and the appended claims, terms such as "first," "second," etc. are used not in a limiting sense, but for the purpose of distinguishing one component from another.

[0031] Singular expressions used in this specification and the appended claims include plural expressions unless the context clearly indicates that they are singular. Additionally, plural expressions include singular expressions unless the context clearly indicates that they are plural.

[0032] Additionally, numerical ranges used herein include lower and upper limits and all values ​​within the range, increments logically derived from the form and width of the defined range, all of which are limited values, and all possible combinations of upper and lower limits of numerical ranges defined in different forms. Unless otherwise specifically defined in the specification of this disclosure, values ​​outside the numerical range that may occur due to experimental error or rounding of values ​​are also included in the defined numerical range.

[0033] Terms such as "approximately" used in this specification and the appended claims are used to encompass tolerances when tolerances exist.

[0034] Hereinafter, a method for manufacturing a three-dimensional porous composite metal compound structure of the present disclosure will be described in detail.

[0035] A method for manufacturing a three-dimensional porous composite metal compound structure according to the present disclosure comprises: (a) a step of manufacturing a three-dimensional porous photoresist mold by irradiating a phase mask of a porous structure in contact with a photoresist with near-field light; (b) a step of manufacturing a first structure by depositing a composite metal compound on the surface of the photoresist mold using atomic layer deposition; (c) a step of manufacturing a second structure by removing the photoresist mold contained in the first structure; and (d) a step of manufacturing a three-dimensional porous composite metal compound structure by annealing the second structure.

[0036] The method for manufacturing a three-dimensional porous composite metal compound structure according to the present disclosure is manufactured by the aforementioned method, which prevents the structure of the composite metal compound structure from collapsing and suppresses changes in the physical and chemical properties of the composite metal compound. Accordingly, a high-quality three-dimensional porous composite metal compound structure having high crystallinity can be manufactured.

[0037] Since the composite metal compound is deposited in a particulate form on the surface of the photoresist mold and is not deposited unevenly, but is deposited uniformly while covering the photoresist mold in the form of a thin film, a three-dimensional porous composite metal compound structure having a uniform pore pattern can be manufactured even during mold removal and annealing.

[0038] The above step (a) is a step of manufacturing a three-dimensional porous photoresist mold by irradiating a porous phase mask in contact with the photoresist with near-field light, and more specifically, a three-dimensional porous photoresist mold can be manufactured by irradiating a porous phase mask in contact with at least a portion of a photoresist layer coated on a substrate with near-field light.

[0039] The phase mask described above may have a protrusion having a pattern in which multiple irregularities protruding in one direction from the surface are spaced apart from each other and periodically repeat. When the phase mask comes into contact with the photoresist, it can make close contact without any separate external pressure. By inducing optical alignment through close contact between the phase mask and the photoresist, pattern precision and resolution can be effectively improved.

[0040] The above-described phase mask comprises an elastomer having flexibility and high elasticity, so that it can come into close contact with the photoresist without applying external pressure. As an example, the above-described phase mask comprises a thermoplastic polymer elastomer comprising a thermoplastic styrene block copolymer, a thermoplastic polyolefin elastomer (TPO), a thermoplastic polyurethane (TPU), a thermoplastic polyamide (TPA), a thermoplastic polyethylene (TPE), a thermoplastic vulcanizate (TPV), or a copolymer thereof;and polydimethylsiloxane, acrylonitrile butadiene rubber, chlorosulfonated polyethylene rubber, ethylene acrylated rubber, fluorocarbon rubber, hydrogenated acrylonitrile butadiene rubber, perfluoroelastomer, thermoset polyurethane rubber, thermoset styrene butadiene rubber, thermoset chloroprene rubber, epichlorohydrin copolymer rubber, ethylene propylene diene rubber, polydimethylsiloxane (PDMS), fluorosilicone rubber, and natural rubber It may include a thermosetting polymer elastomer comprising polyisoprene rubber, polyacrylate rubber, or a combination thereof, preferably polydimethylsiloxane (PDMS), but the present disclosure is not limited thereto.

[0041] When near-field light is irradiated onto a phase mask in contact with a photoresist, scattered light is generated, causing optical interference in the photoresist, and thereby, the photoresist exposed to the near-field light can form chemically and / or physically deformed regions. Subsequently, after removing the phase mask, a photoresist mold having a three-dimensional porous nanostructure pattern corresponding to the phase mask can be manufactured by removing the deformed regions or the undeformed regions. Specifically, the photoresist mold may have a three-dimensional porous structure comprising a plurality of mutually spaced pores.

[0042] In this context, near-field light refers to the electric field formed by electric field lines near the surface of a material—that is, at a location much closer than the wavelength of the light—while electric field lines at the outer edge refer to scattered light that propagates while diffracting toward the distant side.

[0043] Near-field light may include, without limitation, any laser in a wavelength band capable of causing physical and / or chemical changes in the photoresist, specifically, it may be a laser in the ultraviolet or visible light wavelength band, and more specifically, the near-field light may be an ultraviolet laser having a wavelength of 200 to 400 nm, 250 to 380 nm, or 300 to 360 nm. Ultraviolet lasers having the above wavelengths have less thermal influence and a high absorption rate, so they prevent damage to the photoresist mold caused by the near-field light and allow light to be irradiated delicately and precisely, making it easy to form nano patterns.

[0044] The above photoresist is a photosensitive photoreactive material that undergoes chemical and / or physical changes upon exposure to near-field light, thereby allowing a pattern to be formed as the deformed region selectively dissolves or does not dissolve in the developer. In one embodiment, the photoresist may include a negative-type photoresist that polymerizes or crosslinks upon exposure and does not dissolve in the developer. The negative-type photoresist has excellent adhesion to the phase mask, allowing for the uniform formation of precise fine patterns by maintaining close contact with the phase mask.

[0045] In one example, the photoresist may include a phenolic polymer, and preferably may be an NR-based photoresist.

[0046] When using the above NR-based photoresist, the photoresist template is easily removed under an organic solvent such as ethanol, so the composite metal compound deposited on the surface of the photoresist template is not damaged or its structure collapses through the steps described below, thereby enabling the production of a high-quality three-dimensional porous composite metal compound.

[0047] In a non-limiting embodiment, when using a photoresist containing an epoxy polymer, such as SU-8 photoresist, the process of removing the photoresist mold in step (c) described below must necessarily involve a high temperature of 500°C or higher and / or ultrasonic treatment, which is undesirable as it increases the risk of structural collapse of the three-dimensional porous composite metal compound finally produced by damaging the composite metal compound deposited on the surface of the photoresist mold.

[0048] The above step (b) is a step of manufacturing a first structure by depositing a composite metal compound on the surface of the photoresist mold using atomic layer deposition.

[0049] By depositing a composite metal compound on the surface of a photoresist mold while precisely controlling the thickness using atomic layer deposition, a high-quality three-dimensional porous composite metal compound structure with a uniform thickness can be manufactured.

[0050] The above composite metal compound may include at least one metal element belonging to groups 14 to 16 of the periodic table, preferably at least two metal elements belonging to groups 14 to 16 of the periodic table.

[0051] For example, the above composite metal compound may include one or more selected from the group comprising Bi2S3, Bi2Se3, Bi2Te3, Sb2Se3, Sb2Te3, Cu2Se, Cu2Te, Ag2Se, Ag2Te, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbS, PbSe, PbTe, AgBiS2, AgBiSe2, AgBiTe2, AgSbS2, AgSbSe2, AgSbTe2, CuBiS2, CuBiSe2, CuBiTe2, CuSbS2, CuSbSe2, and CuSbTe2, and preferably may include Sb2Se3, which can be uniformly deposited in the form of a thin film on the surface of an NR-based photoresist, has a single crystal phase, and has very high structural stability.

[0052] More specifically, step (b) may include: (b-1) supplying a first metal compound precursor to a reactor into which the photoresist mold is introduced; (b-2) supplying a purge gas to the reactor into which the first metal precursor is supplied; (b-3) supplying a second metal precursor to the reactor into which the purge gas is supplied; and (b-4) supplying a purge gas to the reactor into which the second metal precursor is supplied.

[0053] A composite metal compound can be deposited on the surface of a photoresist mold to a desired thickness by performing steps (b-1) to (b-4) once as one cycle and repeating the cycle at least once. More specifically, step (b) may be performed for 1 to 50,000 cycles, 10 to 10,000 cycles, 100 to 1,000 cycles, or 500 to 1,000 cycles, but the present disclosure is not limited thereto.

[0054] The first metal precursor and the second metal precursor may each independently include at least one metal element belonging to Groups 14 to 16 of the periodic table described above, and in one embodiment, when the composite metal compound is Sb2Se3, the first metal precursor and the second metal precursor contain different types of metal elements, each independently including antimony(III) chloride, antimony(V) chloride, antimony(III) ethoxide, antimony(V) fluoride, antimony(III) propoxide, antimony(III) β-diketonate, antimony(III) acetylacetonate, and triethylantimony. Antimony compounds selected from the group;or bis(trimethylsilyl)selenide, bis(dimethylsilyl)selenide, bis(triethylsilyl)selenide, bis(diethylsilyl)selenide, bis(t-butyldimethylsilyl)selenide, dimethylsilylmethyl selenide, dimethylsilyl t-butyl selenide, trimethylsilyl methyl selenide, dimethylselenium, diethylselenium, selenium hexafluoride and It may include a selenium compound selected from the group including trimethylsilyl-t-butyl selenide. In a preferred example, the antimony compound may include antimony(III) ethoxide, and the selenium compound may include bis(trimethylsilyl)selenide.

[0055] When a composite metal compound is deposited after manufacturing a photoresist mold by the method according to the present disclosure, the composite metal compound is deposited in a particulate form on the surface of the photoresist mold and is not deposited unevenly, but is deposited uniformly in the form of a thin film that surrounds the photoresist mold, so that the surface of the photoresist mold may not be exposed on the outermost side of the first structure. Accordingly, even if the photoresist mold is removed and annealed through the subsequent steps (c) and (d), the structure of the composite metal compound does not collapse or its physical properties deteriorate, and a three-dimensional porous composite metal compound structure having a uniform pore pattern can be manufactured.

[0056] In one example, step (c) is a step of manufacturing a second structure by removing a photoresist template included in the first structure, and the second structure can be manufactured by removing the photoresist template included in the first structure using an organic solvent.

[0057] The above organic solvent may be included without limitation as long as it is capable of selectively removing the aforementioned negative-type photoresist.

[0058] Specifically, the organic solvent is a linear alcohol such as ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, etc.; a diol such as 1,5-pentanediol, 1,6-hexanediol, etc.; a branched alcohol such as 2-methyl-1-butanol, 4-methyl-2-pentanol, etc. It may include one or more selected from the group comprising glycol ethers such as diethyleneglycol monomethyl ether, diethyleneglycol monoethyl ether, triethyleneglycol monomethyl ether, triethyleneglycol monobutyl ether, propyleneglycol monomethyl ether, propyleneglycol monoethyl ether, and propyleneglycol propyl ether; and preferably may include ethanol that can selectively remove a photoresist template without deforming the three-dimensional porous composite metal compound structure with an organic solvent.

[0059] Step (d) is a step of manufacturing a three-dimensional porous composite metal compound structure by annealing the second structure. By annealing the second structure obtained after removing the photoresist template in advance using an organic solvent in Step (c), the physical and chemical properties of the composite metal compound are prevented from deteriorating and the three-dimensional porous structure is prevented from collapsing, thereby enabling the production of a high-quality three-dimensional porous composite metal compound structure.

[0060] In one example, the annealing may be performed under temperature conditions of 50 to 400°C, 100 to 350°C, or 150 to 300°C. Alternatively, it may be performed under temperature conditions of 50°C or higher, 70°C or higher, 100°C or higher, 120°C or higher, 150°C or higher, less than 450°C, 400°C or lower, 350°C or lower, or 300°C or lower, and may be within a range between any two of the above values.

[0061] When annealing is performed within the above temperature range, the crystallinity of the composite metal compound can be improved. At the same time, shrinkage of the three-dimensional porous composite metal compound structure does not occur, thereby preventing the structure from collapsing. In addition, the elemental ratio of metal components contained in the three-dimensional porous composite metal compound structure can be increased, and the ratio of impurity elements such as oxygen and carbon can be minimized.

[0062] More specifically, if annealing is performed at a temperature below the above range, it is difficult to improve the crystallinity of the complex metal compound, and if annealing is performed at a temperature exceeding the above range, there is a risk that highly mobile selenium (Se) elements will escape from the structure and cause decay.

[0063] When manufacturing a composite metal compound structure with a three-dimensional porous structure using the method described above, the structure may include a plurality of mutually spaced pores; and a composite metal compound framework located between the adjacent pores, wherein the plurality of mutually spaced pores may include a three-dimensional porous network formed by connecting them to each other.

[0064] The structure of a three-dimensional porous composite metal compound structure can be controlled by adjusting the annealing temperature. Depending on the application of the structure, a three-dimensional porous composite metal compound structure having various structures can be manufactured by adjusting the annealing temperature. In one embodiment, when the annealing temperature is 50°C or higher and less than 300°C, pores may not be formed on the surface of the composite metal compound framework. Alternatively, in a preferred embodiment, when the annealing temperature is 300°C or higher and less than 450°C, nanopores may be formed on the surface of the composite metal compound framework. When nanopores are present on the surface of the framework, the specific surface area of ​​the three-dimensional porous composite metal compound structure is further enhanced, and as the surface area capable of adsorbing gas increases significantly, it has the advantage of having high sensitivity when utilized as a gas detection sensor.

[0065] The present disclosure includes a three-dimensional porous composite metal compound structure manufactured by the method described above. Before describing the three-dimensional porous composite metal compound structure of the present disclosure, detailed descriptions are omitted as the structure, material, shape, size, etc. of the three-dimensional porous composite metal compound structure are the same as those previously described.

[0066] The above three-dimensional porous composite metal compound structure comprises a plurality of mutually spaced pores; and a composite metal compound framework located between the adjacent pores, wherein the mutually spaced plurality of pores may be connected to each other to form a three-dimensional porous network. A three-dimensional porous composite metal compound structure in which pores of uniform size are arranged at regular intervals without the collapse of the pore structure, and adjacent pores are connected to each other to form a network, has an excellent surface area and can effectively improve material, electrical, and thermal conductivity through the pore network. Accordingly, it can be widely utilized for various applications such as catalysts, sensors, thermoelectric devices, and electrochemical devices.

[0067] The shape of the above three-dimensional porous composite metal compound structure can be adopted in various shapes without limitation depending on the application, such as spherical, rod-shaped, or film-shaped, and more specifically, it can have a flexible film shape with excellent heat dissipation effect.

[0068] In one example, when the composite metal compound contains antimony selenide (Sb2Se3), the Sb3d of the three-dimensional porous composite metal compound structure 5 / 2 In the XPS spectrum, the intensity of the first peak (I1) occurring at a binding energy of 530±0.5 eV may be greater than the intensity of the second peak (I2) occurring at a binding energy of 531±0.5 eV.

[0069] The first peak above refers to a peak originating from the bond between antimony and oxygen (Sb-O), and the second peak refers to a peak originating from the bond between antimony and selenium (Sb-Se). That is, the three-dimensional porous composite metal compound structure produced by the method described above can enhance crystallinity and further strengthen electrical, optical, and thermal properties by strengthening the bond between the metal components antimony and selenium, increasing the elemental ratio of these components, and simultaneously minimizing the ratio of oxygen.

[0070] In one embodiment, the three-dimensional porous composite metal compound structure according to the present disclosure can provide excellent performance when used as a gas sensing sensor. As the framework contains micropores and has a high specific surface area, and the three-dimensional porous composite metal compound structure has high crystallinity and maximizes physical adsorption with the target gas, resulting in excellent gas adsorption and sensing capabilities at room temperature, the three-dimensional porous composite metal compound structure of the present disclosure has the advantage of excellent response characteristics and selectivity for nitrogen oxides, specifically toxic nitrogen dioxide (NO2) gas that causes air pollution.

[0071] The present invention will be explained in more detail below through examples.

[0072] (Example 1)

[0073] After spin-coating an NR-based photoresist (Futurrex, Negative resist NR7-80P) on a glass substrate at 1500 rpm for 30 seconds, the substrate was heated on a hot plate at 65 ℃ for 6 minutes and at 95 ℃ for 10 minutes, then irradiated with 365 nm UV light and heated at 130 ℃ for 2 minutes. Subsequently, an NR-based photoresist (Futurrex, Negative resist NR5-6000) was spin-coated at 2000 rpm for 30 seconds, then heated on a hot plate at 55 ℃ for 17 minutes, at 95 ℃ for 60 minutes, and at 130 ℃ for 2 minutes to form a photoresist layer. A polydimethylsiloxane (PDMS) phase mask having a pattern containing irregularities spaced apart at regular intervals was placed on a photoresist layer, and a laser with a wavelength of 355 nm was irradiated. Afterward, the phase mask was removed, and the material was developed for 28 seconds in a solution of RD6 (Futurrex, RESIST DEVELOPER RD6) and deionized water mixed in a ratio of 2:1, for 30 seconds in RD6, and for 1 minute in deionized water. After drying at room temperature, the material was further developed for 15 seconds in a solution of RD6 and deionized water mixed in a ratio of 2:1, for 25 seconds in RD6, and for 1 minute in deionized water to prepare a photoresist mold.

[0074] A photoresist template was introduced into an atomic layer deposition system (CN-1, Atomic Premium), and Sb2Se3 was deposited on the photoresist template. More detailed atomic layer deposition conditions are shown in Table 1 below. Additionally, antimony(III) ethoxide (Sb(OEt)3) was used as the Sb precursor, bis(trimethylsilyl)selenide ((Me3Si)2Se) was used as the Se precursor, and ultra-high purity (99.9999%) Ar gas was used as the purge gas. To maintain uniform deposition of each precursor within the reactor, the temperatures of the chamber, precursor line, and reactant line were all set to 50 ℃, and the heating temperature of the Sb precursor canister was controlled to 40 ℃, while the heating temperature of the Se precursor canister was controlled to 10 ℃.

[0075] A first structure having Sb2Se3 deposited on a photoresist mold was prepared by injecting the Sb2Se3 precursor and purge gas once each as one cycle, and repeating the cycle 900 times.

[0076] Reactor pressure 2.1 Torr Purge gas flow rate 150 sccm Sb precursor flow rate 50 sccm Se precursor flow rate 50 sccm deposition temperature 50 ℃ Sb precursor supply time 10 sec Se precursor supply time 5 sec Purge gas supply time 10 sec deposition rate 0.66 Å / cycle

[0077] After preparing a second structure with the photoresist mold removed by immersing the first structure in ethanol, the structure was annealed at 150°C for 30 minutes to prepare a composite metal compound structure with a three-dimensional porous structure.

[0078] (Example 2)

[0079] A composite metal compound structure with a three-dimensional porous structure was prepared in the same manner as in Example 1, except that the second structure was annealed at 300°C.

[0080] (Example 3)

[0081] A composite metal compound structure with a three-dimensional porous structure was prepared in the same manner as in Example 1, except that the second structure was annealed at 450°C.

[0082] (Comparative Example 1)

[0083] The procedure was performed in the same manner as in Example 1, but using SU-8 photoresist instead of NR-based photoresist, and the first structure was heat-treated at 350°C and 500°C to produce a composite metal compound structure with a three-dimensional porous structure.

[0084] (Comparative Example 2)

[0085] A composite metal compound structure with a three-dimensional porous structure was prepared in the same manner as in Example 1, except that the second structure was not annealed.

[0086] Physical Property Evaluation Methods

[0087] - To analyze the elemental composition of the three-dimensional porous composite metal compound structure and the surface and cross-sectional structure of the sample, Scanning Electron Microscope (SEM) images were obtained using a scanning electron microscope (Jeol Ltd., JSM-7800F Prime) equipped with an Energy-dispersive X-ray Spectroscopy (EDS) detector.

[0088] - To analyze the crystal structure of the three-dimensional porous composite metal compound structure, X-ray diffraction (XRD) analysis was performed using an X-ray diffraction analyzer (Rigaku, Ultima IV). In addition, Grazing Incidence Wide Angle X-ray Scattering (GIWAXS) analysis was measured using the Pohang Accelerator 3C beamline. Specifically, the X-ray energy and incident angle were set to 8.95 keV and 0.36°, respectively, 2D images were collected using an Eiger 4M detector, and the sample-detector distance was set to 215 mm.

[0089] - To analyze the molecular types of the 3D porous composite metal compound structure samples, Raman spectroscopy analysis was performed using a Raman spectrometer (RENISHAW, 514 nm excitation wavelength).

[0090] - To analyze the chemical bonding state of the three-dimensional porous composite metal compound structure, X-ray photoelectron spectroscopy (XPS) analysis was performed using an X-ray photoelectron spectroscopy analyzer (KRATOS AXIS SUPRA).

[0091] - To evaluate the gas sensing performance of the 3D porous composite metal compound structure, the electrical response characteristics to real-time gas inflow were measured using a micro-probe system (MPS-CHH8C, NEXTRON, KOREA) connected to a gas inflow control device.

[0092] Figure 1 is a scanning electron microscope image of the top view of the first structure when manufacturing a three-dimensional porous composite metal compound structure according to Comparative Example 1. When Sb2Se3 was deposited on the surface of an SU-8 photoresist mold by atomic layer deposition as in Comparative Example 1, Sb2Se3 was deposited in a particulate form. That is, when using an SU-8 photoresist mold, Sb2Se3 was deposited non-uniformly in a particulate form on the surface of the photoresist mold, and it could not be deposited uniformly in the form of a thin film.

[0093] Figure 2 is a scanning electron microscope image of a cross-section of a first structure when a three-dimensional porous composite metal compound structure is manufactured using the method according to Comparative Example 1. When observing the top, middle, and bottom surfaces of the first structure in the cross-section with respect to the thickness direction, it was confirmed that, similar to the frontal SEM image of Figure 1, when using an SU-8 photoresist mold, Sb2Se3 was deposited non-uniformly in a particulate form rather than in a thin film form.

[0094] Figures 3 and 4 are scanning electron microscope images observing the cross-sectional view and top view of a three-dimensional porous composite metal compound structure prepared by the method according to Comparative Example 1. Referring to Figures 3 and 4, Comparative Example 1 not only used an SU-8 photoresist template but also immediately heat-treated the first structure at a high temperature to remove the template and simultaneously prepare the three-dimensional porous composite metal compound structure without a template removal process using an organic solvent. As a result, shrinkage occurred, causing the structure of Sb2Se3 to collapse and exhibiting a highly non-uniform pore size.

[0095] Figure 5 is a scanning electron microscope image and an EDS mapping image showing the elemental distribution of a three-dimensional porous composite metal compound prepared by the method according to Comparative Example 1. Referring to Figure 5, the three-dimensional porous composite metal compound of Comparative Example 1 showed a very low sum of atomic percentages of antimony (Sb) and selenium (Se) at 2.91 atomic percentages, while the sum of atomic percentages of carbon (C) and oxygen (O) was 97.09 atomic percentages. This indicates that the impurity content in the three-dimensional porous composite metal compound is excessively high, resulting in low quality.

[0096] FIG. 6 is a scanning electron microscope image showing cross-sections of a photoresist template (3D NR polymeric template), a first structure (Sb2Se3-coated 3D NR), and a second structure (3D thin-shell Sb2Se3) when preparing a three-dimensional porous composite metal compound by the method according to Example 1. Referring to FIG. 6, when the first structure was prepared by depositing Sb2Se3 on the surface of an NR-based photoresist template using atomic layer deposition, the Sb2Se3 was deposited very homogeneously in the form of a thin film rather than in a particulate form. When the second structure was prepared by removing the photoresist template of the first structure using an organic solvent, a three-dimensional porous pattern corresponding to the photoresist template was formed without the structure of Sb2Se3 collapsing.

[0097] FIG. 7 is a photograph, XRD spectrum, and scanning electron microscope images of the front and cross-sectional structures of the three-dimensional porous composite metal compound structures according to Comparative Example 2 (before annealing), Example 1 (annealed at 150°C_30 min), Example 2 (annealed at 300°C_30 min), and Example 3 (annealed at 450°C_30 min). As shown in FIG. 7, the three-dimensional porous composite metal compound structure of Comparative Example 2, which was not annealed, had almost no crystallinity, whereas the crystallinity of the three-dimensional porous composite metal compound structure of Example 1, which was annealed at 150°C, was significantly improved. The three-dimensional porous composite metal compound structure of Example 2, annealed at 300°C, was also confirmed to have excellent crystallinity through the XRD spectrum, just like Example 1, and an aligned three-dimensional porous composite metal compound structure containing a periodic pore pattern was formed without the structure of the composite metal compound framework collapsing. However, the three-dimensional porous composite metal compound structure of Example 3, in which the annealing temperature was raised to 450°C, lost its crystallinity and the structure collapsed, making it impossible to manufacture a high-quality three-dimensional porous composite metal compound structure.

[0098] More specifically, FIG. 8 shows GIWAXS images of three-dimensional porous composite metal compound structures according to (a) Comparative Example 2 (before annealing), (b) Example 1 (annealed at 150°C), and (c) Example 2 (annealed at 300°C), respectively. Referring to FIG. 8, no circular diffraction pattern (Debye-Scherrer ring) was observed in the three-dimensional porous composite metal compound structure of Comparative Example 2, which was not subjected to annealing treatment. On the other hand, it can be seen that distinct circular diffraction patterns were formed in the three-dimensional porous composite metal compound structures of Example 1 and Example 2, which were annealed at 150°C and 300°C, respectively. This suggests that in the case of Example 1 and Example 2, crystallinity was improved during the annealing process and the thin films were uniformly arranged.

[0099] Figure 9 is the GIWAXS XRD spectrum of a three-dimensional porous composite metal compound structure according to Comparative Example 2 (before annealing), Example 1 (annealed at 150°C), and Example 2 (annealed at 300°C).

[0100] Figure 9(a) shows the results measured in the in-plane direction (plane (xy) direction), and Figure 9(b) shows the results measured in the out-of-plane direction (plane perpendicular (z) direction). Referring to Figure 9(a), no distinct diffraction peaks were observed in the three-dimensional porous composite metal compound structures of Comparative Example 2 and Example 1; however, in the case of Example 2, which was annealed at 300°C, distinct diffraction peaks were observed on the (020) crystal planes reflecting the van der Waals surface, indicating that grain growth had occurred. On the other hand, in Figure 9(b), which was measured in the out-of-plane direction, there was not a significant difference in peak intensity between the three-dimensional porous composite metal compound structures of Comparative Example 2, Example 1, and Example 2. This suggests that the three-dimensional porous composite metal compound structure of Example 2, annealed at 300°C, can enhance structural stability by forming a large amount of van der Waals bonds on the surface of the structure.

[0101] FIG. 10 is a scanning electron microscope image showing the cross-section of a three-dimensional porous composite metal compound structure according to Comparative Example 2 (Before annealing), Example 1 (Annealed at 150°C), Example 2 (Annealed at 300°C), and Example 3 (Annealed at 450°C), respectively. The three-dimensional porous composite metal compound structures of Examples 1 and 2 maintained their structure and improved crystallinity during annealing, but the three-dimensional porous composite metal compound structure of Example 3 could not produce a high-quality three-dimensional porous composite metal compound structure because metal elements such as antimony and selenium escaped during annealing, causing shrinkage and structural collapse.

[0102] In addition, although the three-dimensional porous composite metal compound structure of Example 1 could not confirm the presence of pores on the surface of the composite metal compound framework, the three-dimensional porous composite metal compound structure of Example 2 had nanopores on the surface of the composite metal compound framework, confirming that the structure of the three-dimensional porous composite metal compound structure could be controlled according to the heat treatment temperature.

[0103] FIG. 11 shows the Raman spectra of a photoresist template (3D NR), a first structure (Sb2Se3-coated 3D NR), and a three-dimensional porous composite metal compound structure (3D Sb2Se3) when a three-dimensional porous composite metal compound structure is prepared by the method according to Example 1. No notable Raman peak was detected in the photoresist template, but the first structure, in which Sb2Se3 was deposited on the photoresist template, showed a peak of 251 cm⁻¹. -1 at α-Sb2O3, 210 cm -1 from Sb2Se3Ag 1 and 190 cm -1 from Sb2Se3Ag 2 A peak corresponding to was detected with weak intensity. The three-dimensional porous composite metal compound structure is common to the first structure at 251 cm⁻¹. -1 , 210 cm -1 and 190 cm -1 A peak was detected at 190 cm⁻¹, in particular. -1 from Sb2Se3Ag 2 The intensity of the peak corresponding to was very high, confirming that the crystallinity of the three-dimensional porous composite metal compound structure was improved and the ratio of antimony and selenium elements increased.

[0104] Figure 12 shows the XPS spectra of Sb 3d and Se 3d of three-dimensional porous composite metal compound structures according to Comparative Example 2 (Before annealing), Example 1 (Annealed at 150°C), Example 2 (Annealed at 300°C), and Example 3 (Annealed at 450°C), respectively.

[0105] Referring to FIG. 12, the three-dimensional porous composite metal compound structures of Example 1 and Example 2 each show Se 3d in the Se 3d XPS spectrum. 3 / 2 and Se 3d 5 / 2 A peak corresponding to zero-valence Se was detected. In addition, in the Sb 3d XPS spectrum, the peak intensity for the Sb-Se bond was higher than that for the Sb-O bond, confirming that the proportion of oxygen in the three-dimensional porous composite metal compound structure was lowered while the proportion of metal components such as Sb and Se was simultaneously increased. Meanwhile, in the three-dimensional porous composite metal compound of Example 3, as the annealing temperature increased compared to Examples 1 and 2, a phenomenon occurred in which Sb and Se elements were released. Consequently, no peaks were observed in the Se 3d XPS spectrum, and in the Sb 3d XPS spectrum, peaks corresponding to the Sb-Se bond were also not observed at bond energies of 539.5±0.4 eV and 528±0.2 eV.

[0106] FIG. 13(a) is a graph evaluating the response characteristics of three-dimensional porous composite metal compound structures of Comparative Example 2 (3D Sb2Se3_0), Example 1 (3D Sb2Se3_150), Example 2 (3D Sb2Se3_300), and Example 3 (3D Sb2Se3_150) by exposing them to 100 ppm NO2 gas at room temperature (RT). Referring to FIG. 13(a), Example 2 showed a response sensitivity to NO2 gas of 127.6, which is significantly higher than that of other examples and comparative examples at room temperature. On the other hand, in the case of Example 1, the sensitivity to NO2 gas was measured to be relatively low, which can be interpreted as being due to the fact that the crystallinity of the three-dimensional porous composite metal compound structure of Example 1 was insufficient compared to that of Example 2. In addition, the three-dimensional porous composite metal compound structures of Comparative Example 2 and Example 3 did not have micropores formed in the framework, had low crystallinity, and no reaction to NO2 gas was observed as structural collapse occurred.

[0107] Figure 13(b) is a graph showing the response characteristics of the three-dimensional porous composite metal compound structure according to Example 2 at room temperature (RT) according to NO2 gas concentration. Referring to Figure 13(b), as the NO2 gas concentration decreased sequentially from 100 ppm to 1 ppm, the sensitivity of the sensor also gradually decreased. This demonstrates that the sensor based on the fabricated three-dimensional porous composite metal compound structure possesses quantitative detection performance at various NO2 gas concentrations.

[0108] FIG. 14(a) is a graph showing the response characteristics measured when the three-dimensional porous composite metal compound structure according to Example 2 was repeatedly exposed to NO₂ gas at a concentration of 100 ppm 10 times at room temperature (RT). Referring to FIG. 14(a), when NO₂ gas supply and gas supply interruption were each performed once as one cycle, the response characteristics did not deteriorate and a constant sensitivity was maintained even when the cycle was repeated 10 times. Therefore, it was confirmed that when the three-dimensional porous composite metal compound structure of Example 2 is used as a NO₂ gas detection sensor, it exhibits high stability and reliability and can operate continuously without performance degradation even with repeated use.

[0109] FIG. 14(b) is a graph showing the response characteristics when the three-dimensional porous composite metal compound structure according to Example 2 is exposed to NO2 gas at a concentration of 100 ppm at room temperature (RT) for 3 months. Referring to FIG. 14(b), the sensitivity after 1 month showed a slight decrease compared to the initial response characteristics, but the sensitivity gradually recovered over time, showing a sensitivity comparable to the initial response characteristics after 3 months. This suggests that the three-dimensional porous composite metal compound structure of Example 2 can maintain high sensitivity characteristics even during long-term use due to its high durability and reliability.

[0110] Figure 15 is a graph showing the response characteristics measured when the three-dimensional porous composite metal compound structure according to Example 2 was exposed to 100 ppm of NO2, NH3, toluene (C6H5CH3), H2, and H2S gases, respectively, at room temperature (RT). Referring to Figure 15, the three-dimensional porous composite metal compound structure of Example 2 showed almost no response to ammonia (NH3), toluene, and hydrogen (H2) gases, and showed a negligible response to hydrogen sulfide (H2S) gas. On the other hand, it showed very high sensitivity characteristics to NO2 gas, confirming its potential to be utilized as a high-sensitivity NO2 gas sensor with high selectivity even at room temperature.

[0111] Figure 16 is a graph comparing the reactivity of gas sensors containing various composite metal compound structures. It can be confirmed that the three-dimensional porous composite metal compound structure of Example 2 exhibits significantly higher sensitivity characteristics compared to other sensors, even at a low NO2 concentration of 1 ppm. This suggests that Sb2Se3 is formed as a single crystal phase unlike other chalcogenide compounds and possesses stoichiometric stability, and that gas sensing performance is improved due to the increased specific surface area caused by the three-dimensional porous structure.

[0112] Conventional gas sensors including oxide semiconductors are mainly based on chemical adsorption, and due to the large bandgap, they require energy such as high temperature and light irradiation, which limits operation at room temperature. However, the three-dimensional porous composite metal compound structure of the present disclosure having the aforementioned features detects NO2 gas by physically adsorbing it onto the surface of the structure at room temperature without a separate energy source, thereby enabling the realization of a gas sensor with high sensitivity even at room temperature.

[0113] As described above, the present invention has been explained by specific details, limited embodiments, and drawings; however, this is provided merely to aid in a more comprehensive understanding of the invention and is not limited to the above embodiments. Those skilled in the art can make various modifications and variations from this description.

[0114] Accordingly, the scope of the present invention is not limited to the described embodiments, and all things equivalent to or having equivalent variations to the claims set forth below, as well as the claims set forth below, shall be considered to fall within the scope of the concept of the present invention.

Claims

Claim 1 (a) a step of manufacturing a three-dimensional porous composite metal compound structure by irradiating a photoresist in contact with a phase mask of a porous structure with near-field light; (b) a step of manufacturing a first structure by depositing a composite metal compound on the surface of the photoresist mold by atomic layer deposition; (c) a step of manufacturing a second structure by removing the photoresist mold contained in the first structure; and (d) a step of manufacturing a three-dimensional porous composite metal compound structure by annealing the second structure; comprising a method for manufacturing a three-dimensional porous composite metal compound structure. Claim 2 A method for manufacturing a three-dimensional porous composite metal compound structure according to claim 1, wherein the annealing is performed under temperature conditions of 50 to 400°C. Claim 3 A method for manufacturing a three-dimensional porous composite metal compound structure according to claim 1, wherein the surface of the photoresist mold is not exposed on the outermost side of the first structure. Claim 4 A method for manufacturing a three-dimensional porous composite metal compound structure, wherein, in claim 1, the near-field light is a laser in the ultraviolet or visible light wavelength band. Claim 5 A method for manufacturing a three-dimensional porous composite metal compound structure, wherein, in claim 4, the near-field light is an ultraviolet laser having a wavelength band of 200 to 400 nm. Claim 6 A method for manufacturing a three-dimensional porous composite metal compound structure according to claim 1, wherein the composite metal compound contains at least one metal element belonging to groups 14 to 16 of the periodic table. Claim 7 A method for manufacturing a three-dimensional porous composite metal compound structure according to claim 6, wherein the composite metal compound comprises one or more selected from the group including Bi2S3, Bi2Se3, Bi2Te3, Sb2Se3, Sb2Te3, Cu2Se, Cu2Te, Ag2Se, Ag2Te, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbS, PbSe, PbTe, AgBiS2, AgBiSe2, AgBiTe2, AgSbS2, AgSbSe2, AgSbTe2, CuBiS2, CuBiSe2, CuBiTe2, CuSbS2, CuSbSe2, and CuSbTe2. Claim 8 A method for manufacturing a three-dimensional porous composite metal compound structure, wherein, in claim 1, step (c) is to remove a photoresist mold contained in the first structure using an organic solvent. Claim 9 A method for manufacturing a three-dimensional porous composite metal compound structure according to claim 1, wherein the photoresist mold has a three-dimensional porous structure comprising a plurality of mutually spaced pores. Claim 10 A method for manufacturing a three-dimensional porous composite metal compound structure according to claim 1, wherein the photoresist comprises a phenolic photoresist. Claim 11 A three-dimensional porous composite metal compound structure manufactured by a method according to any one of claims 1 to 10. Claim 12 In claim 11, the three-dimensional porous composite metal compound structure comprises: a plurality of mutually spaced pores; and a composite metal compound framework located between the adjacent pores; wherein the mutually spaced plurality of pores are connected to each other to form a three-dimensional porous network. Claim 13 In claim 11, Sb 3d of the above three-dimensional porous composite metal compound structure 5 / 2 A three-dimensional porous composite metal compound structure in which, in the XPS spectrum, the intensity of the first peak (I1) occurring at a binding energy of 530±0.5 eV is greater than the intensity of the second peak (I2) occurring at a binding energy of 531±0.5 eV. Claim 14 A nitrogen oxide sensing sensor comprising a three-dimensional porous composite metal compound structure manufactured by a method according to any one of claims 1 to 10.

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