Self-supporting graphene array and preparation method, application and device thereof

Abstract

The invention relates to the technical field of suspended graphene film materials, in particular to a self-supporting graphene array and a preparation method, application and device thereof. The invention provides a preparation method of a self-supporting graphene array, which comprises the following steps: S1, placing a graphene film with a growth substrate in an etching solution, and etching to remove the growth substrate to obtain a graphene film floating on the surface of the etching solution; s2, the graphene film floating on the surface of the etching liquid is transferred to a self-supporting ring, and then air pressure difference is generated on the two sides of the graphene film; a target array substrate is attached to the surface of the graphene film on the low-pressure side, and the self-supporting graphene array is obtained. According to the preparation method provided by the invention, the binding force between the graphene film and the target array substrate is effectively improved, so that the graphene film can be attached to the target array substrate, and the suspension rate is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of suspended graphene film materials technology, specifically to a self-supporting graphene array and its preparation method, application, and apparatus. Background Technology

[0002] Micro-Electro-Mechanical Systems (MEMS) have developed rapidly in recent years and are widely used in the high-performance sensor industry. MEMS technology based on self-supporting graphene has further improved device performance and possesses enormous application potential, attracting widespread attention from academia and industry. The application of graphene to MEMS chips requires steps such as graphene film growth, film transfer to the target array substrate, and device packaging. Transfer is a crucial step, determining the integrity and pre-stress stability of the sensitive diaphragm element, ultimately affecting the chip's response performance.

[0003] Methods for transferring graphene films to target array substrates are divided into two main categories: dry methods and wet methods. In existing technologies, dry methods are difficult to transfer large-area graphene films, and the suspension rate of the film array after transfer is low. In existing technologies, during the wet transfer process, the presence of liquid in the target array substrate can easily cause the graphene film to break during the removal of the solution within the array, resulting in a decrease in the suspension rate. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the lack of a method for transferring large-size graphene films to a target array substrate in the prior art, thereby providing a self-supporting graphene array and its preparation method, application and device.

[0005] This invention provides a method for preparing a self-supporting graphene array, comprising the following steps: S1, The graphene film with the growth substrate is placed in the etching solution and the growth substrate is etched away to obtain the graphene film floating on the surface of the etching solution. S2, the graphene film floating on the surface of the etching solution is transferred to the self-supporting ring, and then a pressure difference is generated on both sides of the graphene film; the target array substrate is attached to the surface of the graphene film on the low-pressure side, thus obtaining the self-supporting graphene array.

[0006] Transferring nanoscale-thickness graphene films to millimeter-sized target array substrates (arrays containing micrometer-sized suspended regions) is extremely challenging. Existing technologies, whether using dry or wet methods, struggle to effectively improve the array's suspension rate. After transferring the graphene film onto a support ring, the van der Waals forces between the support ring and the graphene film can effectively fix the film without damaging it. The applicant's research revealed that by cleverly applying a pressure difference, the graphene film can adhere to the target array substrate, effectively improving the suspension rate.

[0007] It is understandable that after the graphene film is transferred onto the self-supporting ring, no relative sliding will occur at the contact point between the graphene film and the self-supporting ring, where a pressure difference is generated on both sides of the film, or during the process of the target array substrate being attached to the surface of the graphene film on the low-pressure side.

[0008] Preferably, the material of the self-supporting ring is metal, plastic, glass, or ceramic.

[0009] Preferably, the process of transferring the graphene film floating on the surface of the etching solution to the self-supporting ring is to place the support ring in the etching solution and drain the etching solution so that the graphene film falls onto the support ring, thus realizing the transfer of the graphene film floating on the surface of the etching solution to the self-supporting ring. Preferably, the process of transferring the graphene film floating on the surface of the etching solution to the self-supporting ring involves replacing the etching solution with a first solvent, placing the support ring in the first solution, and then draining the first solution to allow the graphene film to fall onto the support ring, thus achieving the transfer of the graphene film floating on the surface of the etching solution to the self-supporting ring.

[0010] Preferably, the suspended area of ​​the graphene film after being transferred onto the self-supporting ring is 0.2 mm. 2 Up to 35000mm 2 .

[0011] Preferably, the ratio of the equivalent diameter corresponding to the suspended area of ​​the graphene film after it is transferred to the self-supporting ring to the thickness of the graphene film is 50,000-5,000,000.

[0012] Preferably, the graphene film transferred to the self-supporting ring has a first side and a second side, wherein the second side is in contact with the surface of the supporting ring; The process of generating a pressure difference across the graphene film involves placing the first and second sides of the graphene film in a first atmosphere and a second atmosphere, respectively, with the pressure of the first atmosphere being greater than that of the second atmosphere.

[0013] Preferably, the pressure difference generated on both sides of the graphene film is greater than or equal to 10 Pa.

[0014] Preferably, the target array substrate has a plurality of openings on the side that is bonded to the graphene film, and the openings suspend the graphene film. The plurality of openings form an array; Preferably, the array is selected from a rectangular array, a cellular array, or a ring array; Preferably, the material of the target array substrate includes SiO2, silicon nitride, polymer materials, metal materials, and ceramic materials; Preferably, the projection of the opening onto the graphene film is a regular or irregular shape; More preferably, the projection of the opening onto the graphene film includes a circle, an ellipse, a square, a rectangle, or a polygon; Preferably, the equivalent diameter of the projection of the opening onto the graphene film is 5-2000 μm.

[0015] Preferably, the target array substrate surface is further provided with a groove, the groove is provided in the edge region of the array, and the groove penetrates the target array substrate surface; Preferably, the aspect ratio of the groove is less than 50000; Preferably, the distance between the slot and the nearest opening in the array is 5 to 10,000 μm.

[0016] The present invention also provides an apparatus for preparing a self-supporting graphene array, comprising: The body has an internal cavity and an opening at the top. A support ring is movably provided at the opening, and the support ring is used to support the graphene film; A target array substrate moving platform is positioned opposite to the opening, wherein the target array substrate moving platform supports the bonding of the target array substrate to the surface of the graphene film; The body also includes a gas flow port, which is used to adjust the air pressure inside the body cavity.

[0017] The present invention also provides a self-supporting graphene array, which is prepared by the preparation method described above or by the device described above.

[0018] The present invention also provides a self-supporting graphene array prepared by the above-described preparation method, a self-supporting graphene array prepared by the above-described apparatus, or the application of the above-described self-supporting graphene array in the fields of photoelectric sensors, acoustic diaphragms, acoustic detectors, and micro / nano devices.

[0019] The technical solution of this invention has the following advantages: 1. This application provides a method for preparing a self-supporting graphene array, comprising the following steps: S1, placing a graphene film with a growth substrate in an etching solution, etching away the growth substrate to obtain a graphene film floating on the surface of the etching solution; S2, transferring the graphene film floating on the surface of the etching solution to a self-supporting ring, and then creating a pressure difference between the two sides of the graphene film; attaching the target array substrate to the surface of the graphene film on the low-pressure side to obtain the self-supporting graphene array.

[0020] After the graphene film is transferred onto the support ring, the van der Waals forces between the support ring and the graphene film can effectively fix the graphene film without damaging it. Furthermore, by cleverly applying a pressure difference, the bonding force between the graphene film and the target array substrate is effectively improved, thereby enabling the graphene film to adhere to the target array substrate and effectively improving the suspension rate.

[0021] 2. The target array substrate surface itself is also provided with a groove, which is located in the edge region of the array and penetrates the target array substrate surface.

[0022] The groove effectively removes excess gas between the graphene film and the target array substrate, thereby further enhancing the adhesion performance of the graphene film to the target array substrate and further improving the suspension rate. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a flowchart illustrating a method for preparing a self-supporting graphene array according to an embodiment of the present invention. Figures 2-6 This is a schematic diagram illustrating the fabrication process of the self-supporting graphene array in an embodiment of the present invention; Figure 7 This is a schematic diagram of the target array substrate structure in an embodiment of the present invention; Figure 8 A schematic diagram of the substrate trench of the target array; Figure 9 This is a partial optical micrograph of the self-supporting graphene array prepared using this embodiment; Figure 10 A partial optical micrograph of a self-supporting graphene array prepared by another method; Figure 11This is a partial optical micrograph of a self-supporting graphene array prepared by another method.

[0025] Figure label: 11. Growth substrate; 10. Graphene film; 12. Etching solution; 13. Support ring; 101. First surface; 102. Second surface; 14. Body; 15. Cavity; 16. Target array substrate moving platform; 17. Target array substrate; 18. Gas flow port; 19. Opening. Detailed Implementation

[0026] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of this invention, it should be noted that the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] Example This embodiment provides a method for preparing a self-supporting graphene array, such as... Figure 1 As shown, it includes the following steps: S1, The graphene film with the growth substrate is placed in the etching solution and the growth substrate is etched away to obtain the graphene film floating on the surface of the etching solution. S2, the graphene film floating on the surface of the etching solution is transferred to the self-supporting ring, and then a pressure difference is generated on both sides of the graphene film; the target array substrate is attached to the surface of the graphene film on the low-pressure side, thus obtaining the self-supporting graphene array.

[0031] The pressure difference only causes tension in the graphene film within the suspended area on the support ring, without causing the graphene film to slide relative to the support ring or to break.

[0032] refer to Figure 2-6 The preparation method is described, and references are provided. Figure 2 The graphene film 10 with the growth substrate 11 is placed in the etching solution 12, and the growth substrate 11 is etched away to obtain the graphene film 10 floating on the surface of the etching solution 12, as shown. Figure 3 As shown.

[0033] In one embodiment, the process of transferring the graphene film 10 floating on the surface of the etching solution 12 to the self-supporting ring 13 involves placing the support ring 13 in the etching solution 12 (e.g., Figure 4 As shown, the etching solution 12 is discharged, causing the graphene film 10 to fall onto the support ring 13, thus realizing the transfer of the graphene film 10 floating on the surface of the etching solution 12 to the support ring 13.

[0034] In another embodiment, the process of transferring the graphene film 10 floating on the surface of the etching solution 12 to the self-supporting ring 13 involves replacing the etching solution 12 with a first solvent, placing the support ring 13 in the first solution, and draining the first solution to allow the graphene film 10 to fall onto the support ring 13, thereby achieving the transfer of the graphene film 10 floating on the surface of the etching solution 12 to the self-supporting ring 13.

[0035] In one specific embodiment, the self-supporting ring 13 is made of metal, plastic, glass, or ceramic.

[0036] In one specific embodiment, the first solvent is selected from deionized water or an aqueous solution of sodium dodecyl sulfonate.

[0037] In one specific embodiment, the suspended area of ​​the graphene film 10 after being transferred onto the self-supporting ring 13 is 0.2 mm. 2 Up to 35000mm 2 .

[0038] In one specific embodiment, the ratio of the equivalent diameter corresponding to the suspended area of ​​the graphene film after it is transferred onto the self-supporting ring to the thickness of the graphene film is 50,000-5,000,000, for example, 50,000, 55,000, 100,000, 300,000, 600,000, 1,000,000, 2,000,000, or 5,000,000.

[0039] The graphene film 10 transferred to the self-supporting ring 13 has a first surface 101 and a second surface 102, wherein the second surface 102 is in contact with the surface of the supporting ring 13. In one embodiment, the process of generating a pressure difference across the graphene film 10 involves placing the first side 101 and the second side 102 of the graphene film 10 in a first atmosphere and a second atmosphere, respectively, with the pressure of the first atmosphere being greater than the pressure of the second atmosphere.

[0040] In one specific embodiment, the pressure difference generated across the graphene film 10 is greater than or equal to 10 Pa, for example: 10 Pa, 20 Pa, 50 Pa, 80 Pa, 100 Pa, 200 Pa, 300 Pa or 400 Pa.

[0041] In one specific embodiment, the process of generating a pressure difference across the graphene film 10 and the process of attaching the target array substrate 17 to the surface of the graphene film 10 on the low-pressure side are performed in an apparatus for preparing a self-supporting graphene array, such as... Figure 5 As shown, it includes: a body 14, the interior of which is a cavity 15, and an opening at the top of the body 14; a support ring 13 movably disposed at the opening, the support ring 13 being used to support a graphene film 10; a target array substrate moving platform 16 disposed opposite to the opening, wherein the target array substrate moving platform 16 carries the target array substrate 17 to be attached to the surface of the graphene film 10; the body 14 also includes a gas flow port 18, the gas flow port 18 being used to adjust the gas pressure inside the cavity 15 of the body 14.

[0042] The process of preparing the self-supporting graphene array is as follows: after transferring the graphene film 10 to the self-supporting ring 13, the support ring 13 is placed at the opening of the body 14, and part of the air in the cavity 15 is extracted through the gas flow port 18, forming a pressure difference between the first surface 101 and the second surface 102 of the graphene film 10. Then, the target array substrate 17 is attached to the second surface 102 by moving the target array substrate moving platform 16, thus obtaining the self-supporting graphene array.

[0043] In one embodiment, a schematic diagram of the target array substrate 17 structure is shown below. Figure 7 As shown, the target array substrate 17 has a plurality of openings 19 on the side that is attached to the graphene film 10, and the graphene film 10 is suspended in the area of ​​the openings 19; wherein, the plurality of openings 19 form an array.

[0044] In one specific embodiment, the array is selected from a rectangular array, a cellular array, or a ring array.

[0045] In one specific embodiment, the projection of the opening 19 onto the graphene film 10 is a regular or irregular shape. In a more specific embodiment, the projection of the opening 19 onto the graphene film 10 includes a circle, an ellipse, a square, a rectangle, or a polygon.

[0046] In one specific embodiment, the equivalent diameter of the projection of the opening 19 onto the graphene film 10 is 5-2000 μm; for example, 5 μm, 10 μm, 50 μm, 80 μm, 100 μm, 500 μm, 1000 μm or 2000 μm.

[0047] In one embodiment, the material of the target array substrate 17 includes SiO2, silicon nitride, polymer materials, metal materials, or ceramic materials.

[0048] In a specific embodiment, such as Figure 8 As shown, the target array substrate 17 is further provided with a groove 20, which is located in the edge region of the array and penetrates the surface of the target array substrate 17.

[0049] Compared to the target array substrate 17 without grooves 20, the suspension rate of the graphene film 10 on the target array substrate 17 can be further improved after grooves 20 are opened. The grooves 20 can effectively remove excess gas between the graphene film 10 and the target array substrate 17.

[0050] In one specific embodiment, the aspect ratio of the groove is less than 50000, for example 20, 50, 100, 500, 1000, 5000, 10000, 20000 or 40000.

[0051] The aspect ratio is the ratio of depth to width.

[0052] When the aspect ratio is higher than 50000, the graphene film 10 is prone to collapse and stick to the bottom of the groove 20, and cannot play the role of reducing excess residual gas.

[0053] In one specific embodiment, the distance between the slot 20 and the nearest opening 19 in the array is 5 to 10000 μm; for example, 5 μm, 10 μm, 50 μm, 100 μm, 200 μm, 500 μm, 1000 μm, 2000 μm, 5000 μm or 10000 μm.

[0054] If the distance between the groove 20 and the opening 19 is greater than 10,000 μm, there is too much graphene film 10 bonding area between the groove 20 and the opening 19, and excess residual gas cannot be discharged through the groove 20; if the distance between the groove 20 and the opening 19 is less than 5 μm, there is too little graphene film 10 bonding between the groove 20 and the opening 19, resulting in poor airtightness of the cavity 15, and the film in the suspended area on the opening 19 is prone to collapse.

[0055] The slots 20 are set according to the array formed by the openings 19. When the array is a rectangular array, four slots 20 parallel to the sides of the rectangular array are set; when the array is a honeycomb array or a ring array, four mutually perpendicular slots 20 are set, and the slots 20 form a square.

[0056] Figure 9 This is a partial optical micrograph of the self-supporting graphene array prepared using this embodiment. The graphene film 10 has a thickness of 20 nm; the supporting ring 13 is made of SiO2; the first solvent is a 0.4 mmol / L aqueous solution of sodium dodecyl sulfate; and the suspended area of ​​the graphene film 10 after being transferred onto the self-supporting ring 13 is 314 mm². 2 (The suspended area is circular); the process of generating a pressure difference across the graphene film 10 involves placing the first surface 101 and the second surface 102 of the graphene film 10 in a first atmosphere and a second atmosphere, respectively, with a pressure difference of 104.55 Pa; the opening 19 in the target array substrate 17 is centered and has a diameter of 80 μm; the openings 19 in the target array substrate 17 form a square array; the surface of the target array substrate 17 is also provided with four grooves, which are parallel to the square array; the distance between the groove and the nearest opening 19 in the square array is 400 μm; the width of the groove is 5 μm; and the depth is 100 μm. From Figure 9 It can be seen that all graphene films 10 can achieve effective suspension without any film breakage or sticking to the bottom, and the suspension rate reaches 100%. Figure 10 This is a partial optical micrograph of a self-supporting graphene array prepared by another method, the preparation method of which is similar to... Figure 9 The difference in the preparation method of the self-supporting graphene array is that no pressure difference is generated on both sides of the graphene film 10, and the target array substrate 17 is directly bonded to the graphene film 10. It can be seen that there are many areas where the substrate is not effectively suspended.

[0057] Figure 11 This is a partial optical micrograph of a self-supporting graphene array prepared by another method. The preparation method of the self-supporting graphene array is similar to... Figure 9 The difference in the preparation method of the self-supporting graphene array is that the target array substrate 17 does not have four grooves on its surface. It can be seen that there are many large and small air bubbles that affect the adhesion between the graphene film 10 and the substrate.

[0058] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a self-supporting graphene array, characterized in that, Includes the following steps: S1, The graphene film with the growth substrate is placed in the etching solution and the growth substrate is etched away to obtain the graphene film floating on the surface of the etching solution. S2, the graphene film floating on the surface of the etching solution is transferred to the self-supporting ring, and then a pressure difference is generated on both sides of the graphene film; the target array substrate is attached to the surface of the graphene film on the low-pressure side, thus obtaining the self-supporting graphene array.

2. The preparation method according to claim 1, characterized in that, The self-supporting ring is made of metal, plastic, glass, or ceramic.

3. The preparation method according to claim 1, characterized in that, The process of transferring the graphene film floating on the surface of the etching solution to the self-supporting ring involves placing the support ring in the etching solution and then draining the etching solution to allow the graphene film to fall onto the support ring, thus achieving the transfer of the graphene film floating on the surface of the etching solution to the self-supporting ring. Preferably, the process of transferring the graphene film floating on the surface of the etching solution to the self-supporting ring involves replacing the etching solution with a first solvent, placing the support ring in the first solution, and then draining the first solution to allow the graphene film to fall onto the support ring, thus achieving the transfer of the graphene film floating on the surface of the etching solution to the self-supporting ring.

4. The preparation method according to claim 1, characterized in that, After the graphene film is transferred onto the self-supporting ring, its suspended area is 0.2 mm. 2 Up to 35000mm 2 .

5. The preparation method according to claim 1, characterized in that, The graphene film transferred to the self-supporting ring has a first side and a second side, wherein the second side is in contact with the surface of the supporting ring; The process of generating a pressure difference across the graphene film involves placing the first and second sides of the graphene film in a first atmosphere and a second atmosphere, respectively, with the pressure of the first atmosphere being greater than that of the second atmosphere.

6. The preparation method according to claim 1, characterized in that, The target array substrate has several openings on the side that is attached to the graphene film, and the opening areas suspend the graphene film. The plurality of openings form an array; Preferably, the array is selected from a rectangular array, a cellular array, or a ring array; Preferably, the material of the target array substrate includes SiO2, silicon nitride, polymer materials, metal materials, or ceramic materials; Preferably, the projection of the opening onto the graphene film is a regular or irregular shape; More preferably, the projection of the opening onto the graphene film includes a circle, an ellipse, a square, a rectangle, or a polygon; Preferably, the equivalent diameter of the projection of the opening onto the graphene film is 5-2000 μm.

7. The preparation method according to claim 6, characterized in that, The target array substrate surface is also provided with a groove, which is located in the edge region of the array and penetrates the target array substrate surface; Preferably, the aspect ratio of the groove is less than 50000; Preferably, the distance between the slot and the nearest opening in the array is 5 to 10,000 μm.

8. An apparatus for preparing a self-supporting graphene array, characterized in that, include: The body has an internal cavity and an opening at the top. A support ring is movably provided at the opening, and the support ring is used to support the graphene film; A target array substrate moving platform is positioned opposite to the opening, wherein the target array substrate moving platform supports the bonding of the target array substrate to the surface of the graphene film; The body also includes a gas flow port, which is used to adjust the air pressure inside the body cavity.

9. A self-supporting graphene array, characterized in that, It is prepared by the preparation method according to any one of claims 1-7 or by the apparatus according to claim 8.

10. The application of a self-supporting graphene array prepared by the preparation method according to any one of claims 1-7, a self-supporting graphene array prepared by the device according to claim 7, or a self-supporting graphene array according to claim 8 in the fields of photoelectric sensors, acoustic diaphragms, acoustic detectors, and micro / nano devices.

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