Graphene transfer method
By performing current hot melting of the metal substrate in a vacuum environment, combined with cleaning and annealing treatment, the problems of pollution and defects during graphene transfer are solved, and high-quality graphene transfer and device performance improvement are achieved.
Patent Information
- Application Number
- CN202411352743.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2025-02-07
AI Technical Summary
In the prior art, the transfer process of graphene cannot be cleanly and completely transferred from the metal substrate to the functional substrate, resulting in defects such as polymer contamination and water doping, limiting device performance.
The metal substrate is removed in a vacuum environment by using current hot melt treatment, avoiding the use of polymer transfer media such as PMMA, and removing water vapor and impurities on the interface between the graphene layer and the functional substrate through cleaning and annealing treatment.
The clean and complete transfer of the graphene layer is achieved, interface defects are reduced, carrier mobility and performance of the device are improved, and yields of subsequent devices are improved.
Smart Images
Figure CN119390062A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of low-dimensional material preparation, and in particular to a graphene transfer method. Background Art
[0002] Graphene has excellent optical, electrical and mechanical properties, and has considerable potential in the development of electronic and photonic devices. Since its advent, how to efficiently prepare graphene has always attracted the attention of scientific researchers, and theories and methods for preparing graphene have emerged in an endless stream. Growing graphene on a metal substrate by chemical vapor deposition (CVD) is considered to be the most promising way to mass-produce graphene films with competitive performance. Copper has the characteristic of low carbon solubility, and high-quality graphene wafers can be produced on a copper substrate.
[0003] However, in order to apply graphene to various electronic and optoelectronic devices, transferring it from metal substrates to functional substrates remains an inevitable obstacle on the road to true commercial application of chemical vapor deposition graphene films. Traditional wet transfer usually uses polymethyl methacrylate (PMMA) film and other supporting films (PC, PPC, pinene alcohol, linalool, borneol, etc.) as transfer media to support graphene so that it can be separated from the metal substrate surface and transferred from the liquid surface to the functional substrate. During the wet transfer process, solutions such as PMMA cannot be completely removed, which may introduce defects such as polymer contamination and water doping. These defects act as additional scattering centers, limit the carrier mobility of graphene, and reduce device performance.
[0004] In view of this, there is an urgent need for a method for transferring graphene from a metal substrate to a functional substrate cleanly and completely. Summary of the invention
[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a method for transferring graphene, which is used to solve the problem that in the prior art, graphene cannot be cleanly and completely transferred from a metal substrate to a functional substrate during the transfer process of graphene.
[0006] To achieve the above object and other related objects, the present invention provides a graphene transfer method, comprising the following steps:
[0007] Providing a structure to be transferred, the structure to be transferred comprising a metal substrate and a graphene layer formed on the metal substrate;
[0008] Providing a functional substrate, placing the structure to be transferred on the functional substrate, and the graphene layer is in contact with the functional substrate;
[0009] Performing an electric current heat melting treatment on the metal substrate in an environment of a preset vacuum degree to remove the metal substrate and allow the graphene layer to adhere to the functional substrate;
[0010] The functional substrate with the graphene layer attached thereto is sequentially cleaned and annealed.
[0011] Optionally, the functional substrate includes at least one of quartz, silicon / silicon dioxide, sapphire, and hexagonal boron nitride.
[0012] Optionally, the electric current hot-melt treatment of the metal substrate includes the following steps: providing a conductive metal clamp and a current device, using the conductive metal clamp to clamp the structure to be transferred to place a sample on the functional substrate; installing the conductive metal clamp on the current device, starting the current device and increasing the current of the current device, heating the conductive metal clamp to a first preset temperature and maintaining it for a first preset time; increasing the current of the current device, heating the conductive metal clamp to a second preset temperature and maintaining it for a second preset time, so as to melt the metal substrate.
[0013] Optionally, the first preset temperature ranges from 720°C to 730°C; the first preset time ranges from 60s to 120s; the second preset temperature ranges from 740°C to 760°C; and the second preset time ranges from 8s to 12s.
[0014] Optionally, the preset vacuum degree is less than 2.5×10 -4 Pa.
[0015] Optionally, before the metal substrate is subjected to the electric current hot-melt treatment, a protective film covering the functional substrate and the structure to be transferred is provided.
[0016] Optionally, after the metal substrate is subjected to the current hot-melt treatment and before the functional substrate to which the graphene layer is attached is cleaned, the method further includes etching the metal substrate remaining after the current hot-melt treatment.
[0017] Optionally, the time range for etching the metal substrate is 5.5 hours to 7 hours, and the etching solution used for etching the metal substrate includes ammonium persulfate.
[0018] Optionally, cleaning the functional substrate with the graphene layer attached thereto comprises the following steps: providing a plurality of deionized water cleaning devices and an organic solvent cleaning device, placing the functional substrate with the graphene layer attached thereto into the corresponding deionized water cleaning devices in turn and cleaning them for a corresponding period of time, and then placing the functional substrate with the graphene layer attached thereto into the organic solvent cleaning device and cleaning them for a corresponding period of time.
[0019] Optionally, the atmosphere used for annealing the functional substrate with the graphene layer attached thereto is an argon-hydrogen mixed gas, the annealing temperature ranges from 550° C. to 650° C., and the annealing time ranges from 5.5 h to 6.5 h.
[0020] As described above, the graphene transfer method of the present invention has the following beneficial effects: by sequentially performing an electric current hot-melt treatment on the metal substrate in a preset vacuum environment, and etching the metal substrate after the electric current hot-melt treatment in an etching solution to remove the metal substrate, compared with the traditional wet transfer, the transfer process does not use PMMA, thereby avoiding the introduction of polymers, and the transfer process is completed in a vacuum environment, thereby minimizing the introduction of bubbles and defects at the interface between the graphene layer and the functional substrate, and by cleaning the exposed surface of the graphene layer after removing the metal substrate, and annealing the graphene layer and the functional substrate, the graphene layer can be successfully transferred from the metal substrate to the functional substrate, while the water vapor and impurities adsorbed on the interface between the graphene layer and the functional substrate can be effectively removed, so that the graphene layer and the functional substrate are more closely bonded, thereby improving the yield rate of the subsequently formed device. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 Shown is a schematic diagram of the graphene transfer process of the present invention.
[0022] Figure 2 Shown is a schematic structural diagram of a structure to be transferred in the graphene transfer method of the present invention.
[0023] Figure 3 An optical microscope image showing a structure to be transferred according to the graphene transfer method of the present invention.
[0024] Figure 4 It is a schematic diagram showing the structure of the graphene transfer method of the present invention after placing the structure to be transferred on a functional substrate.
[0025] Figure 5 Shown is a schematic structural diagram of a current device and a conductive metal clip in the graphene transfer method of the present invention.
[0026] Figure 6 It is a schematic diagram showing the structure of the graphene transfer method of the present invention after the metal substrate is subjected to electric current heat melting treatment.
[0027] Figure 7 Shown is a schematic structural diagram of the graphene transfer method of the present invention after the metal substrate is removed.
[0028] Figure 8An optical microscope image showing the graphene transfer method of the present invention after the graphene layer is transferred to a functional substrate.
[0029] Fig. 9 Another optical microscope image showing the graphene transfer method of the present invention after the graphene layer is transferred to a functional substrate.
[0030] Fig.10 The third optical microscope image shows the graphene transfer method of the present invention after the graphene layer is transferred to the functional substrate.
[0031] Fig.11 Shown as the present invention Fig.10 Raman spectrum in the middle red area.
[0032] Fig.12 Shown as the present invention Fig.10 Topographic channel diagram of the heterojunction region of the functional substrate / graphene layer in atomic force microscopy tapping mode.
[0033] Fig.13 Shown as the present invention Fig.10 Phase channel map of the heterojunction region of the functional substrate / graphene layer in atomic force microscopy tapping mode.
[0034] Fig.14 A morphological channel diagram showing the heterojunction region of a functional substrate / graphene layer in the graphene transfer method of the present invention under the contact mode of an atomic force microscope.
[0035] Fig.15 A lateral force channel diagram showing a heterojunction region of a functional substrate / graphene layer in the graphene transfer method of the present invention under an atomic force microscope contact mode.
[0036] Fig.16 Shown as the present invention Fig.15 Domain map of the selected area.
[0037] Fig.17 Another morphological channel diagram showing the heterojunction region of the functional substrate / graphene layer in the graphene transfer method of the present invention under the contact mode of the atomic force microscope.
[0038] Fig.18 Another lateral force channel diagram showing the heterojunction region of a functional substrate / graphene layer in the graphene transfer method of the present invention in the atomic force microscope contact mode.
[0039] Fig.19 Shown as the present invention Fig.18 Domain map of the selected area.
[0040] Component number description
[0041] 1 Structure to be transferred
[0042] 11 Metal substrate
[0043] 12 Graphene layers
[0044] 2 Functional substrate
[0045] 3 Conductive metal clips
[0046] 31 First Metal Sheet
[0047] 32 Second metal sheet
[0048] 4 Current device
[0049] 5 Samples to be processed DETAILED DESCRIPTION
[0050] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.
[0051] See also Figures 1 to 19 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.
[0052] Embodiment 1
[0053] This embodiment provides a graphene transfer method. Figure 1 As shown, it is a schematic diagram of the graphene transfer process, which includes the following steps:
[0054] S1: providing a structure to be transferred, wherein the structure to be transferred includes a metal substrate and a graphene layer formed on the metal substrate;
[0055] S2: providing a functional substrate, placing the structure to be transferred on the functional substrate, and the graphene layer is in contact with the functional substrate;
[0056] S3: performing an electric current heat melting treatment on the metal substrate in a preset vacuum environment to remove the metal substrate and allow the graphene layer to adhere to the functional substrate;
[0057] S4: sequentially performing cleaning and annealing treatments on the functional substrate with the graphene layer attached thereto.
[0058] For details, please refer to Figure 2-Figure 3 , perform step S1 to provide a structure 1 to be transferred, wherein the structure 1 to be transferred includes a metal substrate 11 and a graphene layer 12 formed on the metal substrate 11 .
[0059] Specifically, Figure 2 , which is a schematic structural diagram of a structure to be transferred 1 , wherein the material of the metal substrate 11 includes copper or other suitable metal materials.
[0060] Specifically, Figure 3 As shown, it is an optical microscope image of the structure 1 to be transferred. When copper is used as the metal substrate 11, the graphene layer 12 grows uniformly on the metal substrate 11.
[0061] Specifically, the metal substrate 11 is used to provide a flat growth platform for the graphene layer 12 , which helps to form a uniform graphene layer 12 .
[0062] Specifically, the method of forming the graphene layer 12 includes chemical vapor deposition or other suitable methods.
[0063] Specifically, the sizes of the metal substrate 11 and the graphene layer 12 can be selected according to actual conditions and are not limited here.
[0064] For details, please refer to Figure 4 , perform step S2, provide a functional substrate 2, place the structure 1 to be transferred on the functional substrate 2, and the graphene layer 12 is in contact with the functional substrate 1.
[0065] As an example, the functional substrate 2 includes quartz, silicon / silicon dioxide, sapphire, hexagonal boron nitride or other suitable functional substrates.
[0066] Specifically, Figure 4 , which is a schematic diagram of the structure after the structure to be transferred 1 is placed on the functional substrate 2. The method of placing the structure to be transferred 1 on the functional substrate 2 includes fixture transfer.
[0067] Specifically, the fixture used to place the structure to be transferred 1 on the functional substrate 2 includes tweezers.
[0068] For details, please refer to Figure 5-Figure 7, executing step S3, performing an electric current heat-melting treatment on the metal substrate 11 in an environment with a preset vacuum degree to remove the metal substrate 11 and allow the graphene layer 12 to adhere to the functional substrate 2.
[0069] As an example, before the metal substrate 11 is subjected to the electric current heat-melting treatment, a protective film (not shown) covering the functional substrate 2 and the structure to be transferred 1 is provided.
[0070] Specifically, the protective film includes graphite paper or other suitable materials.
[0071] As an example, Figure 5-Figure 6 As shown in the figure, they are respectively a schematic diagram of the structure of the conductive metal clip 3 and the current device 4 and a schematic diagram of the structure of the metal substrate 11 after the current heat melting treatment (it should be noted that Figure 5 The sample to be processed 5 in the figure represents a sample to be subjected to electric current hot-melt treatment after the structure to be transferred 1 is placed on the functional substrate 2 and wrapped with a protective film). The electric current hot-melt treatment of the metal substrate 11 includes the following steps: providing a conductive metal clamp 3 and a current device 4, and using the conductive metal clamp 3 to clamp the sample of the structure to be transferred 1 placed on the functional substrate 2; installing the conductive metal clamp 3 on the current device 4, starting the current device 4 and increasing the current of the current device 4, heating the conductive metal clamp 3 to a first preset temperature and maintaining it for a first preset time; increasing the current of the current device 4, heating the conductive metal clamp 3 to a second preset temperature and maintaining it for a second preset time, so as to melt the metal substrate 11.
[0072] As an example, the preset vacuum degree is less than 2.5×10 -4 Pa.
[0073] Specifically, the conductive metal clip 3 includes a first metal sheet 31 and a second metal sheet 32 which are arranged opposite to each other.
[0074] Specifically, the first metal sheet 31 includes a tungsten boat or other suitable devices; the second metal sheet 32 includes a tungsten boat or other suitable devices.
[0075] As an example, the first preset temperature ranges from 720°C to 730°C; the first preset time ranges from 60s to 120s; the second preset temperature ranges from 740°C to 760°C; the second preset time ranges from 8s to 12s. In this embodiment, the first preset temperature is 730°C and the second preset time is 10s.
[0076] Specifically, graphite paper with good heat resistance and thermal conductivity is used as a protective film, which protects the metal substrate 11 from being affected during the electric current hot melt treatment. At the same time, the protective film can limit the heat to a specific space to ensure that the metal substrate 11 can be fully melted. In addition, the protective film can also limit the melted metal substrate 11 to a specific area, so that the metal substrate 11 melts and flows to the surface of the protective film to avoid affecting the vacuum device.
[0077] Specifically, after the metal substrate 11 is subjected to the electric current heat-melting treatment, the method further includes taking out a sample of the metal substrate 11 subjected to the electric current heat-melting treatment from the protective film.
[0078] Specifically, before taking out the sample after the electric current heat-melting treatment of the metal substrate 11 from the protective film, the current of the current device needs to be reduced to 0 within 1 minute to avoid danger when taking out the sample after the electric current heat-melting treatment of the metal substrate 11 from the protective film.
[0079] Specifically, in a vacuum device, an electric current hot-melt treatment method is used to remove the metal substrate 11. Compared with the traditional wet transfer, PMMA is not used in the transfer process, which avoids the introduction of polymers. The transfer process is completed in a vacuum environment, which minimizes the introduction of bubbles at the interface between the graphene layer and the functional substrate, and fewer defects are introduced during the transfer process.
[0080] As an example, Figure 7 As shown, it is a schematic diagram of the structure after removing the metal substrate 11. After the metal substrate 11 is subjected to electric current hot-melt treatment, before the functional substrate 2 with the graphene layer 12 attached thereto is cleaned, it also includes the step of etching the metal substrate 11 remaining after the electric current hot-melt treatment.
[0081] As an example, the time range of etching the metal substrate 11 is 5.5 hours to 7 hours. In this embodiment, the time of etching the metal substrate 11 is 6 hours, and the etching solution used for etching the metal substrate 11 includes ammonium persulfate or other suitable etching solutions.
[0082] Specifically, the concentration of the etching solution is less than 1 mol / L.
[0083] Specifically, by using an ammonium persulfate solution as an etching solution, the metal substrate 11 remaining after the current hot-melt treatment can be effectively etched away, while having little impact on the graphene layer 12 .
[0084] For details, please refer to Figure 8-Figure 19 , executing step S4, sequentially performing cleaning treatment and annealing treatment on the functional substrate 2 with the graphene layer 12 attached thereto.
[0085] As an example, the cleaning process of the functional substrate 2 with the graphene layer 12 attached thereto includes the following steps: providing a plurality of deionized water cleaning devices and an organic solvent cleaning device, sequentially placing the functional substrate 2 with the graphene layer 12 attached thereto in the corresponding deionized water cleaning devices and cleaning them for a corresponding time, and then placing the functional substrate 2 with the graphene layer 12 attached thereto in the organic solvent cleaning device and cleaning them for a corresponding time. In this embodiment, the number of the deionized water cleaning devices is four.
[0086] Specifically, the time range for cleaning the functional substrate 2 with the graphene layer 12 attached in the corresponding deionized water cleaning device is 8 minutes to 12 minutes. In the present embodiment, the time for cleaning the functional substrate 2 with the graphene layer 12 attached in the corresponding deionized water cleaning device is 10 minutes. Specifically, the time range for cleaning the functional substrate 2 with the graphene layer 12 attached in the organic solvent cleaning device is 1 minute to 3 minutes. In the present embodiment, the time for cleaning the functional substrate 2 with the graphene layer 12 attached in the organic solvent cleaning device is 1 minute.
[0087] Specifically, the organic solvent in the organic solvent cleaning device includes isopropyl alcohol or other suitable organic solvents.
[0088] Specifically, by cleaning the functional substrate 2 with the graphene layer 12 attached thereto in a plurality of deionized water cleaning devices and an organic solvent cleaning device respectively, the residual impurities on the surface of the graphene layer 12 can be fully and effectively removed. At the same time, isopropyl alcohol is used as the organic solvent. The excellent volatility of isopropyl alcohol can also enable the surface of the graphene layer 12 to dry quickly.
[0089] Specifically, after the exposed surface of the functional substrate 2 with the graphene layer 12 attached is cleaned, the process further includes a step of drying the exposed surface of the functional substrate 2 with the graphene layer 12 attached using a nitrogen gun.
[0090] As an example, the atmosphere used for annealing the functional substrate 2 with the graphene layer 12 attached thereto is an argon-hydrogen mixture, the annealing temperature ranges from 550° C. to 650° C., and the annealing time ranges from 5.5 h to 6.5 h. In this embodiment, the flow ratio of argon to hydrogen in the argon-hydrogen mixture is 100:20 sccm, the annealing temperature is 600° C., and the annealing time is 6 h.
[0091] Specifically, the cleaning and annealing treatments can not only remove the water vapor and impurities adsorbed on the exposed surface of the functional substrate 2 to which the graphene layer 12 is attached, but also make the contact section between the graphene layer 12 and the functional substrate 2 more closely attached.
[0092] Specifically, Figure 8-Figure 9As shown, there are respectively an optical microscope image after the graphene layer 12 is transferred to the functional substrate 2 and another optical microscope image after the graphene layer 12 is transferred to the functional substrate 2. Among them, the functional substrate 2 made of quartz material and the functional substrate 2 of silicon / silicon dioxide can both show the existence of the graphene layer 12 in the optical microscope image, that is, after the above-mentioned process treatment, the graphene layer 12 can be transferred to the functional substrate 2.
[0093] Specifically, Figure 10-13 As shown, they are the third optical microscope images after the graphene layer 12 is transferred to the functional substrate 2, Fig.10 Raman spectrum of the red area, Fig.10 The morphology channel diagram of the heterojunction region of the functional substrate 2 / graphene layer 12 in the tapping mode of the atomic force microscope and Fig.10 Phase channel diagram of the heterojunction region of the functional substrate 2 / graphene layer 12 in the tapping mode of the atomic force microscope. The functional substrate 2 with hexagonal boron nitride is used, the hexagonal boron nitride is cleaved on the surface of the functional substrate 2, and the graphene layer 12 covering the surface of the hexagonal boron nitride is characterized. The Raman spectrum of the region with hexagonal boron nitride in the optical microscope image and the collection of different atomic force microscope images in the tapping mode are performed. The Raman spectrum at 1367cm -1 The peak at 1580cm is the characteristic peak of hexagonal boron nitride. -1 、2677cm -1 The peak at is the characteristic peak of graphene, and the existence of the graphene layer 12 can also be seen in the atomic force microscope images at different contact distances in the tapping mode, that is, the graphene layer 12 is successfully transferred to the functional substrate 2, and the above characterization can further assist in judging the transfer quality of the graphene layer 12.
[0094] Specifically, Figure 14-Figure 19 As shown, they are a morphological channel diagram of the heterojunction region of the functional substrate / graphene layer in the atomic force microscope contact mode, a lateral force channel diagram of the heterojunction region of the functional substrate / graphene layer in the atomic force microscope contact mode, Fig.15 Domain map of the framed area, another morphological channel map of the heterojunction area of the functional substrate / graphene layer in the atomic force microscope contact mode, another lateral force channel map of the heterojunction area of the functional substrate / graphene layer in the atomic force microscope contact mode, and Fig.18 Domain map of the selected area. Moiré fringes can be observed in the domain area of the graphene layer. This is caused by the lattice mismatch between graphene and hexagonal boron nitride. The existence of these moiré fringes indicates that the interface cleanliness in the heterojunction area is high, and there are no significant impurities or defects on the interface. In addition, it is observed that Fig.15 The gap between the moiré fringes of graphene in the graphene is 10nm. Fig.18The gap of the moiré fringes of graphene in the structure is 7nm, and the periods of the moiré fringes in different regions are different, which means that there is a difference in the rotation angle between graphene and hexagonal boron nitride, that is, their crystal directions are inconsistent. By further precisely controlling the rotation angle between graphene and hexagonal boron nitride, the electronic properties of the heterojunction region can be modulated, thereby achieving subsequent optimization of device performance.
[0095] The graphene transfer method of the present embodiment sequentially performs an electric current heat-melting treatment on the metal substrate 11 in an environment of a preset vacuum degree, and then performs an etching treatment on the metal substrate 11 remaining after the electric current heat-melting treatment in an etching solution to remove the metal substrate 11. Compared with the traditional wet transfer, the transfer process does not use PMMA, thereby avoiding the introduction of polymers, and the transfer process is completed in a vacuum environment, thereby minimizing the introduction of bubbles and defects at the interface between the graphene layer 12 and the functional substrate 2. By sequentially cleaning and annealing the functional substrate 2 to which the graphene layer 12 is attached, the graphene layer 12 is successfully transferred from the metal substrate 11 to the functional substrate 2, and at the same time, the water vapor and impurities adsorbed at the interface between the graphene layer 12 and the functional substrate 2 can be effectively removed, so that the graphene layer 12 and the functional substrate 2 are more closely fitted, thereby improving the yield rate of the subsequently formed device.
[0096] In summary, the transfer method of graphene of the present invention performs an electric current hot melt treatment on the metal substrate in a preset vacuum environment in sequence, and performs an etching treatment on the metal substrate after the electric current hot melt treatment in an etching solution to remove the metal substrate. Compared with the traditional wet transfer, the transfer process does not use PMMA, avoiding the introduction of polymers, and the transfer process is completed in a vacuum environment, which minimizes the introduction of bubbles at the interface between the graphene layer and the target substrate, and introduces fewer defects during the transfer process. By sequentially cleaning and annealing the functional substrate with the graphene layer attached, the graphene layer can be successfully transferred from the metal substrate to the functional substrate, and the water vapor and impurities adsorbed on the interface between the graphene layer and the functional substrate can also be effectively removed, so that the graphene layer and the functional substrate are more closely attached, and the device yield formed subsequently is improved. Therefore, the present invention effectively overcomes the various shortcomings in the prior art and has a high industrial utilization value.
[0097] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.
Claims
1. A graphene transfer method, characterized in that: The following steps are involved: Providing a structure to be transferred, the structure to be transferred comprising a metal substrate and a graphene layer formed on the metal substrate; Providing a functional substrate, placing the structure to be transferred on the functional substrate, and the graphene layer is in contact with the functional substrate; Performing an electric current heat-melting treatment on the metal substrate in an environment with a preset vacuum degree to remove the metal substrate and allow the graphene layer to adhere to the functional substrate; The functional substrate with the graphene layer attached thereto is sequentially cleaned and annealed.
2. The graphene transfer method according to claim 1, characterized in that: The functional substrate includes at least one of quartz, silicon / silicon dioxide, sapphire, and hexagonal boron nitride.
3. The graphene transfer method according to claim 1, characterized in that: The electric current hot-melt treatment of the metal substrate includes the following steps: providing a conductive metal clamp and a current device, using the conductive metal clamp to clamp the sample of the structure to be transferred and placed on the functional substrate; installing the conductive metal clamp on the current device, starting the current device and increasing the current of the current device, heating the conductive metal clamp to a first preset temperature and maintaining it for a first preset time; increasing the current of the current device, heating the conductive metal clamp to a second preset temperature and maintaining it for a second preset time, so as to melt the metal substrate.
4. The graphene transfer method according to claim 3, characterized in that: The first preset temperature ranges from 720° C. to 730° C.; the first preset time ranges from 60s to 120s; the second preset temperature ranges from 740° C. to 760° C.; the second preset time ranges from 8s to 12s.
5. The graphene transfer method according to claim 1, characterized in that: The preset vacuum degree is less than 2.5×10 -4 Pa.
6. The graphene transfer method according to claim 1, characterized in that: Before the metal substrate is subjected to the electric current hot-melt treatment, a protective film covering the functional substrate and the structure to be transferred is provided.
7. The graphene transfer method according to claim 1, characterized in that: After the metal substrate is subjected to the current hot-melt treatment, before the functional substrate with the graphene layer attached thereto is cleaned, the method further includes etching the metal substrate remaining after the current hot-melt treatment.
8. The graphene transfer method according to claim 7, characterized in that: The time range for etching the metal substrate is 5.5 hours to 7 hours, and the etching solution used for etching the metal substrate includes ammonium persulfate.
9. The graphene transfer method according to claim 1, characterized in that: The cleaning process of the functional substrate with the graphene layer attached thereto comprises the following steps: providing a plurality of deionized water cleaning devices and an organic solvent cleaning device, placing the functional substrate with the graphene layer attached thereto into the corresponding deionized water cleaning devices in turn and cleaning them for a corresponding period of time, and then placing the functional substrate with the graphene layer attached thereto into the organic solvent cleaning device and cleaning them for a corresponding period of time.
10. The graphene transfer method according to claim 1, characterized in that: The atmosphere used for annealing the functional substrate with the graphene layer attached thereto is an argon-hydrogen mixed gas, the annealing temperature ranges from 550° C. to 650° C., and the annealing time ranges from 5.5 h to 6.5 h.