Preparation method of double-layer suspended three-dimensional nanostructure and double-layer suspended three-dimensional nanostructure

Abstract

The present invention provides a method for preparing a three-dimensional double-layer suspended nanostructure, which is simple to operate, green and environmentally friendly, low in cost, and high in throughput. The plasma-assisted nanotransfer printing technology is used to achieve one-time preparation of the double-layer suspended nanostructure without the need for an additional adhesive layer. The present invention also provides a three-dimensional double-layer suspended nanostructure, which has a unique three-dimensional double-layer suspended structure, has a high specific surface area, and exhibits great application potential.

Description

[Technical field]

[0001] The present invention belongs to the technical field of nanostructures, and more particularly relates to a method for preparing a double-layer suspended three-dimensional nanostructure and a double-layer suspended three-dimensional nanostructure. [Background technology]

[0002] Nanostructure is a new system constructed or assembled according to certain rules based on nanoscale material units. It includes one-dimensional, two-dimensional, and three-dimensional systems, usually referring to tiny structures with a size of less than 100 nanometers. Currently, common micro-nano processing technologies include traditional photolithography, electron beam lithography, and focused ion beam lithography. However, the resolution of traditional photolithography is limited by the wavelength of light, which has limitations in the preparation of nanostructures. Electron beam lithography and focused ion beam lithography have slow processing speeds and are not suitable for large-scale production. In addition, the cost of focused ion beam lithography is expensive.

[0003] Suspended nanostructures have shown great potential in scientific research and industrial applications due to their high specific surface area, uniqueness, and multifunctionality. However, the preparation of suspended nanostructures using the above-mentioned micro-nano processing technologies has the problems of high cost and low throughput. [Summary of the invention]

[0004] The purpose of the present invention is to provide a method for preparing a double-layer suspended three-dimensional nanostructure, so as to solve the problems of high cost and low throughput in the preparation of the current suspended nanostructure.

[0005] Another object of the present invention is to provide a double-layer suspended three-dimensional nanostructure.

[0006] The method for preparing a double-layer suspended three-dimensional nanostructure comprises the following steps:

[0007] S1, nanoimprinting: firstly, coating an imprinting glue on a bottom mold with nanocolumns, and covering a polymer film on the other side of the imprinting glue, and imprinting and replicating a nanopore structure complementary to the nanocolumn structure of the bottom mold onto the imprinting glue, so that the imprinting glue forms a corresponding nanopore structure, and a template is obtained;

[0008] S2, UV curing: using UV to expose the template, so that the embossed adhesive is completely polymerized and cured to form an embossed adhesive layer with nanopores;

[0009] S3, forming a double-layer three-dimensional nanostructure: separating the bottom mold from the template processed in step S2 to obtain a polymer template, wherein the polymer template includes a polymer film and an embossed adhesive layer with nanopores located on one side of the polymer film, and then using a coating machine to deposit metal under vacuum conditions to form a metal particle layer located in the nanopores and a metal hole layer located on the other side of the embossed adhesive layer, wherein the metal particle layer and the metal hole layer form a double-layer nanostructure;

[0010] S4, plasma etching: using plasma to etch the imprinted adhesive of the polymer template treated in step S3, so as to weaken the covalent bond between the imprinted adhesive layers, and obtain a polymer template having a double-layer three-dimensional nanostructure, wherein the imprinted adhesive after plasma etching, the metal particle layer and the metal hole layer constitute the double-layer three-dimensional nanostructure;

[0011] S5, nano-transfer printing: placing the polymer template with a double-layer three-dimensional nanostructure in step S4 on a substrate, and then using a hot nano-imprinter to perform nano-transfer printing on the polymer template with a double-layer three-dimensional nanostructure under certain pressure and temperature conditions for a period of time;

[0012] S6, separation: separating the polymer template with a double-layer three-dimensional nanostructure processed in step S5 from the substrate to obtain a substrate with a double-layer suspended three-dimensional nanostructure.

[0013] In the method for preparing a double-layer suspended three-dimensional nanostructure as described above, in step S3, the metal hole layer includes a plurality of metal holes, the metal particle layer includes a plurality of metal particles, and each of the metal holes corresponds to the position of each metal particle disposed in the nanohole.

[0014] In the method for preparing a double-layer suspended three-dimensional nanostructure as described above, in step S6, the metal particle layer in the double-layer suspended three-dimensional nanostructure is in a suspended state relative to the metal hole layer, and the metal particle layer is suspended on the metal hole layer.

[0015] In the above-mentioned method for preparing a double-layer suspended three-dimensional nanostructure, the shapes of the metal particles and the metal holes are both circular.

[0016] In the above-mentioned method for preparing a double-layer suspended three-dimensional nanostructure, the wavelength range of the UV in step S3 is 200-450 nanometers.

[0017] In the method for preparing the double-layer suspended three-dimensional nanostructure as described above, the template is exposed to UV light twice, and each exposure time of the UV light is 90 seconds.

[0018] In the above-mentioned method for preparing a double-layer suspended three-dimensional nanostructure, the vacuum condition in step S4 is less than 5.1×10-4 Pa.

[0019] In the above-mentioned method for preparing a double-layer suspended three-dimensional nanostructure, the plasma treatment in step S5 is O2 plasma treatment.

[0020] In the above-mentioned method for preparing a double-layer suspended three-dimensional nanostructure, the specific conditions of the O2 plasma treatment are: O2 flow rate is 200sccm, power is 150W, and treatment time is 45min.

[0021] A double-layer suspended three-dimensional nanostructure prepared by the double-layer suspended three-dimensional nanostructure preparation method.

[0022] The present invention proposes a method for preparing a double-layer suspended three-dimensional nanostructure. First, the nanoimprinting technology can overcome the high processing cost problem in common micro-nano processing technologies such as traditional photolithography, electron beam lithography, and focused ion beam lithography, and can achieve mass production. In addition, a bottom mold with a suitable nanocolumn structure can be selected according to the target product application and performance requirements, thereby being able to prepare three-dimensional nanostructures in a more diverse manner. Second, the nano-transfer printing technology is easy to operate and can quickly achieve large-area uniform replication and transfer of nanostructures, thereby reducing costs and increasing product throughput; it has a wide range of applicability and can transfer a variety of target materials (such as gold, silver, copper, platinum, aluminum, etc.) to different types of substrates (such as silicon, germanium, quartz, PMMA film, etc.); the nano-transfer printing technology used is also environmentally friendly and can achieve the transfer of nanostructures without an additional adhesion layer, which not only reduces the use of chemicals but also simplifies the preparation method. No additional adhesion layer spin coating process is required, thereby improving production efficiency. Without the need for an additional adhesion layer, there is no need to consider the compatibility of the adhesion layer with the product material, making material selection more flexible and diversified; without the need for an additional adhesion layer, the accuracy and integrity of the transferred structure can also be improved. Third, plasma-assisted nanotransfer printing technology uses O2 plasma treatment to weaken the covalent bond between the imprinted adhesive layers, which can ensure that a substrate with a double-layer suspended three-dimensional nanostructure can be obtained through a one-step transfer. In addition, compared with common micro-nano processing technologies, plasma treatment does not require additional consumables, such as fuel, chemicals, etc., which greatly reduces production costs. In addition, its process is simple and easy to operate, and the costs of related safety equipment and employee training are also greatly reduced, thereby improving product throughput. Finally, under the high temperature conditions of nanotransfer printing, according to the low melting point effect at the nanoscale, during the transfer process, the metal particles will melt and reassemble, reducing their diameter, that is, the diameter of the metal particles is smaller than the diameter of the metal holes. Figure 7 As shown, this is conducive to the formation of unique nanostructures during the preparation process.

[0023] The method for preparing a double-layer suspended three-dimensional nanostructure of the present invention is simple to operate, green and environmentally friendly, low in cost, and high in throughput. It adopts plasma-assisted nanotransfer printing technology to achieve one-time preparation of a double-layer suspended nanostructure without the need for an additional adhesion layer, thereby solving the current problems of high cost and low throughput in the preparation of suspended nanostructures.

[0024] The present invention also proposes a double-layer suspended three-dimensional nanostructure prepared by the double-layer suspended three-dimensional nanostructure preparation method, which has a unique three-dimensional double-layer suspended structure and a high specific surface area, and shows great potential in scientific research and industrial applications such as optoelectronic devices and sensors.

Brief Description of the Drawings

[0025] Figure 1 It is a schematic diagram of the preparation process of the double-layer suspended three-dimensional nanostructure of the present invention;

[0026] Figure 2 It is a schematic diagram of the nano transfer printing mechanism of the present invention;

[0027] Figure 3 It is an enlarged schematic diagram of a double-layer suspended three-dimensional nanostructure of the present invention;

[0028] Figure 4 This is a SEM image of the double-layer suspended three-dimensional nanostructure of the present invention, tilted at 45° and magnified 2000 times;

[0029] Figure 5 This is a SEM image of the double-layer suspended three-dimensional nanostructure of the present invention, tilted at 45° and magnified 10,000 times;

[0030] Figure 6 This is a SEM image of the double-layer suspended three-dimensional nanostructure of the present invention, tilted at 90° and magnified 50,000 times;

[0031] Figure 7 This is a SEM image of the metal particles and metal holes left after the embossed adhesive layer is removed from the double-layer suspended three-dimensional nanostructure of the present invention. [Specific implementation method]

[0032] Below is a combination of the embodiments and the attached Figure 1-7 The specific technical solution of the present invention is described as follows:

[0033] The method for preparing a double-layer suspended three-dimensional nanostructure comprises the following steps:

[0034] S1, nanoimprinting: firstly, coating an imprinting glue 2 on a bottom mold 1 having nanocolumns 11, and covering the other side of the imprinting glue 2 with a polymer film 3, imprinting and replicating a nanopore structure complementary to the nanocolumn structure 11 of the bottom mold onto the imprinting glue 2, so that the imprinting glue 2 forms a corresponding nanopore structure, and obtaining a template 100. The step S1 is as shown in the attached figure. Figure 1 As shown in (a)-(b), the template 100 is as shown in the attached Figure 1 (b)

[0035] Furthermore, the material of the bottom mold is silicon, quartz or polymer, which provides a basis for the preparation of nanostructures. This embodiment uses silicon material as the bottom mold material. Silicon material has high hardness and good wear resistance, and can maintain the consistency and integrity of the imprinting process; it has good stability to most chemicals;

[0036] Furthermore, the nanocolumn structure can be selected from different types of nanocolumn structures according to the target product application and performance requirements. The nanocolumn structure described in this embodiment is cylindrical;

[0037] Furthermore, the embossed adhesive material can be selected from different materials according to the target product application and performance requirements. This embodiment uses RM-311 resin. The embossed adhesive is used as a medium for structure transfer, and can form a nano-scale structure on it that is complementary to the structure of the bottom mold, ensuring accurate replication of the structure, and is suitable for uniform structuring of a large area;

[0038] Furthermore, the material of the polymer film is PET, PI or other polymer materials, and the present embodiment uses PET film;

[0039] S2, UV curing: UV is used to expose the template 100, so that the embossed adhesive 2 is completely polymerized and cured to form an embossed adhesive layer 5 with nanopores. The step S2 is as shown in the attached figure. Figure 1 As shown in (b)-(c);

[0040] Furthermore, the embossing adhesive can be quickly cured under UV irradiation to form a prepolymer with a certain viscosity. The complete polymerization of the embossing adhesive can ensure the quality and stability of the nanostructure after embossing;

[0041] S3, forming a double-layer three-dimensional nanostructure: separating the bottom mold 1 from the template 100 processed in step S2 to obtain a polymer template 200, wherein the polymer template 200 includes a polymer film 3 and an embossed adhesive layer 5 having nanopores 12 located on one side of the polymer film 3. The steps are as shown in the attached figure. Figure 1 As shown in (c)-(d), the polymer template 200 is as shown in the attached Figure 1 (d′)

[0042] Then, a coating machine is used to deposit metal under vacuum conditions to form a metal particle layer 6 located in the nanopore 12 and a metal hole layer 7 located on the other side of the embossed adhesive layer 5. The metal particle layer 6 and the metal hole layer 7 form a double-layer nanostructure. The steps are as shown in the attached figure. Figure 1 As shown in (d)-(e), the polymer template 200 at this time is as shown in the attached Figure 1 (e′)

[0043] Furthermore, the metal is gold, silver, copper, etc. In specific implementation, appropriate materials can be selected according to the target product application and performance requirements. Because at the nanoscale, the electronic structure and physicochemical properties of the metal will be different from those at the macroscale, and this size effect will affect the performance of the nanostructure. In this embodiment, gold is used as the deposited metal, and its deposition thickness is 20 nanometers;

[0044] S4, plasma etching: plasma etching the embossing glue of the polymer template 200 treated in step S3 to weaken the covalent bond between the embossing glue layers, thereby obtaining a polymer template 300 having a double-layer three-dimensional nanostructure 10. The embossing glue 4, the metal particle layer 6 and the metal hole layer 7 etched by plasma form the double-layer three-dimensional nanostructure 10. Step S4 is as shown in the attached figure. Figure 1 As shown in (e)-(f), the polymer template 300 having a double-layer three-dimensional nanostructure 10 is as shown in the attached Figure 1 (f)

[0045] Further, as attached Figure 2 As shown in (e)-(g), F1 is the covalent bond strength between the imprinted adhesive layers; F 1a is the bonding force between the embossed adhesive 4 after plasma etching and the embossed adhesive 5 without plasma etching; F is the bonding force between the metal and the substrate; F2 is the bonding force between the metal and the embossed adhesive after plasma etching. Before plasma treatment, F2<F<F1; after plasma treatment, F 1a <F2<F, the covalent bond between the imprint adhesive layers can be weakened by plasma treatment, so that the imprint adhesive etched by plasma can support the metal particle layer in the subsequent nano-transfer printing process, and transfer the metal particle layer and the metal hole layer to the substrate together to form a double-layer suspended three-dimensional nanostructure, and the time and intensity of plasma treatment can regulate the morphology and size of the nanostructure, thereby realizing the control of the characteristics of the nanostructure;

[0046] S5, nano-transfer printing: placing the polymer template 300 having the double-layer three-dimensional nanostructure 10 in step S4 on the substrate 8, and then using a hot nano-imprinter to perform nano-transfer printing on the polymer template 300 having the double-layer three-dimensional nanostructure 10 under certain pressure and temperature conditions for a period of time. Step S5 is as shown in the attached figure. Figure 1 As shown in (f)-(g);

[0047] Furthermore, the parameters of nano-transfer printing, such as transfer temperature, pressure and duration, need to be determined according to actual conditions. The transfer temperature and duration need to be determined based on the deposited metal material and thickness. For example: for a gold deposition thickness of 20 nanometers, a transfer temperature of 180°C and a transfer time of 300s are used; for a gold deposition thickness of 30 nanometers, a transfer temperature of 200°C and a transfer time of 300s-600s are used; for a silver deposition thickness of 20 nanometers, a transfer temperature of 120-140°C and a transfer time of about 300s are used. For the same metal, the thicker the deposition thickness, the higher the transfer temperature; for different metals, the higher the melting point of the block, the higher the transfer temperature required at the nanoscale. The transfer pressure will affect the transfer effect. In the pressure range of 1-6 bar, the smaller the pressure, the worse the transfer effect.

[0048] Furthermore, in this embodiment, gold is used as the deposited metal, and the parameters of the nano-transfer printing used are pressure 6 bar, temperature 180° C., and duration 300 s;

[0049] S6, separation: separating the polymer template 300 having the double-layer three-dimensional nanostructure 10 processed in step S5 from the substrate 8 to obtain a substrate 400 having a double-layer suspended three-dimensional nanostructure 20. Step S6 is as shown in the attached figure. Figure 1 (g)-(h) and attached Figure 2 As shown in (g)-(h), the substrate 400 is as shown in the attached Figure 1 (h′) and attached Figure 3 As shown, no additional adhesion layer is required between the double-layer suspended three-dimensional nanostructure and the substrate, and the double-layer suspended three-dimensional nanostructure can be combined with the substrate through chemical adsorption between the metal hole layer and the substrate.

[0050] Furthermore, in step S3 , the metal hole layer 7 includes a plurality of metal holes 71 , and the metal particle layer includes a plurality of metal particles 61 , and each of the metal holes 71 corresponds to a position of each metal particle 61 disposed in the nanopore 12 .

[0051] Furthermore, in step S6, the metal particle layer 6 in the double-layer suspended three-dimensional nanostructure is in a suspended state relative to the metal hole layer 7, and the metal particle layer is suspended on the metal hole layer.

[0052] Furthermore, the metal particles 61 and the metal holes 71 are both circular in shape, and the diameter of the metal particles 61 is smaller than the diameter of the metal holes 71. Figure 7 As shown, the diameters of the metal particles 61 and the metal holes 71 are determined by the structure of the nanorods 11 of the bottom mold 1, as shown in the attached Figure 1(a) As shown in FIG. 1 , the nanorods 11 of the bottom mold 1 used in this embodiment are solid cylindrical structures with a diameter of 400 nanometers and a nanorod structure spacing of 800 nanometers.

[0053] Furthermore, the wavelength range of the UV in step S3 is 200-450 nanometers.

[0054] Furthermore, the template is exposed twice by the UV, and each exposure time of the UV is 90 seconds.

[0055] Furthermore, the vacuum condition in step S4 is less than 5.1×10 -4 Pa.

[0056] Furthermore, the plasma treatment in step S5 is O2 plasma treatment.

[0057] Furthermore, the specific conditions of the O2 plasma treatment are: O2 flow rate of 200 sccm, power of 150 W, and treatment time of 45 min. This embodiment uses a plasma cleaning machine with specifications of "RF radio frequency ion source 13.56 MHz, ICP inductively coupled discharge and maximum power of 200 W" for O2 plasma treatment.

[0058] This embodiment uses the method for preparing the double-layer suspended three-dimensional nanostructure to achieve the preparation of a large-area, uniform double-layer suspended three-dimensional nanostructure on a 2-inch wafer, thereby providing a feasible technical route for the preparation and application of the double-layer suspended three-dimensional nanostructure. The method for preparing the double-layer suspended three-dimensional nanostructure of the present invention shows great application potential.

[0059] The double-layer suspended three-dimensional nanostructure prepared by the double-layer suspended three-dimensional nanostructure preparation method. The double-layer suspended three-dimensional nanostructure is as shown in the attached Figure 4-7 As shown, it has a unique three-dimensional double-layer suspended structure with a high specific surface area.

[0060] The method for preparing a double-layer suspended three-dimensional nanostructure of the present invention is simple to operate, green and environmentally friendly, low in cost, and high in throughput. It adopts plasma-assisted nanotransfer printing technology to achieve one-time preparation of a double-layer suspended nanostructure without the need for an additional adhesion layer, thereby solving the current problems of high cost and low throughput in the preparation of suspended nanostructures.

[0061] The double-layer suspended three-dimensional nanostructure of the present invention has a unique three-dimensional double-layer suspended structure and a high specific surface area, and shows great potential in scientific research and industrial applications such as optoelectronic devices and sensors.

[0062] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a double-layer suspended three-dimensional nanostructure, characterized in that: The following steps are involved: S1, nanoimprinting: firstly, coating an imprinting glue on a bottom mold with nanocolumns, and covering a polymer film on the other side of the imprinting glue, and imprinting and replicating a nanopore structure complementary to the nanocolumn structure of the bottom mold onto the imprinting glue, so that the imprinting glue forms a corresponding nanopore structure, and a template is obtained; S2, UV curing: using UV to expose the template, so that the embossed adhesive is completely polymerized and cured to form an embossed adhesive layer with nanopores; S3, forming a double-layer three-dimensional nanostructure: separating the bottom mold from the template processed in step S2 to obtain a polymer template, wherein the polymer template includes a polymer film and an embossed adhesive layer with nanopores located on one side of the polymer film, and then using a coating machine to deposit metal under vacuum conditions to form a metal particle layer located in the nanopores and a metal hole layer located on the other side of the embossed adhesive layer, wherein the metal particle layer and the metal hole layer form a double-layer nanostructure; S4, plasma etching: using plasma to etch the imprinted adhesive of the polymer template treated in step S3, so as to weaken the covalent bond between the imprinted adhesive layers, thereby obtaining a polymer template having a double-layer three-dimensional nanostructure, wherein the imprinted adhesive, the metal particle layer and the metal hole layer after plasma etching constitute the double-layer three-dimensional nanostructure; S5, nano-transfer printing: placing the polymer template with a double-layer three-dimensional nanostructure in step S4 on a substrate, and then using a hot nano-imprinter to perform nano-transfer printing on the polymer template with a double-layer three-dimensional nanostructure under certain pressure and temperature conditions for a period of time; S6, separation: separating the polymer template with a double-layer three-dimensional nanostructure processed in step S5 from the substrate to obtain a substrate with a double-layer suspended three-dimensional nanostructure.

2. The method for preparing a double-layer suspended three-dimensional nanostructure according to claim 1, characterized in that: In step S3, the metal hole layer includes a plurality of metal holes, the metal particle layer includes a plurality of metal particles, and each of the metal holes corresponds to a position of each metal particle disposed in the nanopore.

3. The method for preparing a double-layer suspended three-dimensional nanostructure according to claim 2, characterized in that: In step S6, the metal particle layer in the double-layer suspended three-dimensional nanostructure is in a suspended state relative to the metal hole layer, and the metal particle layer is suspended on the metal hole layer.

4. The method for preparing a double-layer suspended three-dimensional nanostructure according to claim 3, characterized in that: The metal particles and the metal holes are both circular in shape.

5. The method for preparing a double-layer suspended three-dimensional nanostructure according to claim 1, characterized in that: The wavelength range of the UV in step S3 is 200-450nm.

6. The method for preparing a double-layer suspended three-dimensional nanostructure according to claim 3, characterized in that: The template is exposed twice by the UV, and each exposure time of the UV is 90 seconds.

7. The method for preparing a double-layer suspended three-dimensional nanostructure according to claim 1, characterized in that: The vacuum condition in step S3 is less than 5.1×10 -4 Pa.

8. The method for preparing a double-layer suspended three-dimensional nanostructure according to claim 1, characterized in that: The plasma treatment in step S5 is O2 plasma treatment.

9. The method for preparing a double-layer suspended three-dimensional nanostructure according to claim 8, characterized in that: The specific conditions of the O2 plasma treatment are: O2 flow rate of 200 sccm, power of 150 W, and treatment time of 45 min.

10. A double-layer suspended three-dimensional nanostructure prepared by the method for preparing a double-layer suspended three-dimensional nanostructure according to any one of claims 1 to 9.

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