A take-up and pay-off device for graphene film, a deposition system and a preparation method

Abstract

The application provides a take-up and pay-off device, a plasma enhanced chemical vapor deposition system and a graphene film preparation method. The take-up and pay-off device comprises a pay-off shaft, a take-up shaft, a base and a motor. The pay-off shaft is used for arranging a substrate; the take-up shaft is arranged in parallel with the pay-off shaft and is used for winding the graphene film and the substrate; the base is arranged below the pay-off shaft and the take-up shaft and is used for supporting the pay-off shaft and the take-up shaft; and the motor is connected with the take-up shaft and is used for providing power for the take-up shaft. Through the above design, the graphene film with a large width can be prepared, and the problem that the preparation of the large-size graphene film is limited at present is solved.

Description

Technical Field

[0001] This application relates to apparatus, system and method for preparing graphene films, and more specifically, to a graphene film unwinding and winding device, deposition system and preparation method. Background Technology

[0002] Graphene is a novel carbon material with a two-dimensional honeycomb crystal structure composed of a single layer of tightly packed carbon atoms. It has many excellent properties in terms of electrical conductivity, thermal conductivity, mechanics, and optics, and also has some unique properties, such as high-performance sensor function, catalyst function, hydrogen absorption function, bipolar semiconductor, non-scattering transmission, and stress sensor function. Graphene has obvious application advantages in touch screens.

[0003] Chemical vapor deposition (CVD) is currently the most ideal and widely used technology for preparing graphene in industrial production. The working principle of CVD is to use a carbon source (gaseous, liquid, or solid) in a high-temperature environment, where the carbon source decomposes into carbon atoms that deposit on a metal surface, gradually growing a continuous graphene film. However, the drawbacks of conventional CVD have become increasingly apparent. Therefore, plasma-enhanced chemical vapor deposition (PECVD) has been developed based on CVD. Common plasma sources include three types: microwave, radio frequency (RF), and direct current (DC) discharge. Depending on the plasma source, these are called WPCVD, RF-PECVD, and DC-PECVD, respectively. RF-PECVD technology reduces the cost of graphene film preparation by achieving low-temperature growth and offers advantages such as high film quality, large growth area, and high transparency. It also significantly increases the possibility of preparing high-quality graphene over large areas on high-temperature-sensitive substrates, facilitating the industrial production and practical scientific applications of graphene. Specifically, methane and hydrogen are introduced, and under the action of a radio frequency electric field, the hydrogen is ionized into plasma, which enhances plasma activity and accelerates the reaction. The kinetic energy of the electrons accelerated by the radio frequency electric field is above 10 eV, which can break most of the carbon-hydrogen bonds of methane molecules, and carbon atoms are deposited on the substrate, thereby preparing graphene films.

[0004] In PECVD graphene film preparation systems, the decomposition of different carbon source gases generates contaminants. In the traditional dynamic growth process of PECVD systems, the unwinding and winding hoppers are located on both sides of the heating furnace. This makes it easy for amorphous carbon and other contaminants to deposit in the cold zone near the unwinding hopper, and these contaminants deposited at the cold end can affect sample quality. Secondly, the traditional tube furnace, consisting of a heating furnace and a quartz tube, is limited by the diameter of the quartz tube and cannot produce large-width graphene films. Summary of the Invention

[0005] A primary objective of this application is to overcome at least one of the deficiencies of the prior art described above and to provide an apparatus capable of manufacturing large-width graphene films.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] According to one aspect of this application, a winding and unwinding apparatus is provided for preparing a graphene film, comprising a base, an unwinding shaft, a winding shaft, and a motor. The unwinding shaft is disposed on the base, and the base supports the unwinding shaft; the unwinding shaft is used to place a substrate. The winding shaft is disposed on the base, and the base supports the winding shaft; the winding shaft is arranged parallel to the unwinding shaft and winds up the graphene film and the substrate. The motor is connected to the winding shaft and provides power to the winding shaft.

[0008] According to one embodiment of this application, the unwinding shaft, the winding shaft, and the base are all made of a high-temperature resistant rigid material.

[0009] According to one embodiment of this application, the projection of the base on a plane perpendicular to the axial direction of the unwinding shaft is a rectangle, and both the unwinding shaft and the rewinding shaft are disposed on the same long side of the rectangle.

[0010] According to one embodiment of this application, the projection of the base on a plane perpendicular to the axial direction of the unwinding shaft is a semicircle, and both the unwinding shaft and the rewinding shaft are disposed on the diameter of the semicircle.

[0011] According to one embodiment of this application, the base is either integrally formed or composed of two separate structures.

[0012] According to one embodiment of this application, the base includes a first end base and a second end base, the first end base supporting one end of the unwinding shaft and the rewinding shaft, and the second end base supporting the other end of the unwinding shaft and the rewinding shaft.

[0013] According to one embodiment of this application, the base includes an unwinding shaft base and a rewinding shaft base, wherein the unwinding shaft is disposed on the unwinding shaft base and the rewinding shaft is disposed on the rewinding shaft base.

[0014] According to one embodiment of this application, the base is provided with a groove, a bearing is provided in the groove, the unwinding shaft and the winding shaft are both provided in the bearing, and the bearing is provided with buckles at both ends.

[0015] According to one embodiment of this application, the length of the take-up shaft is greater than the length of the unwind shaft.

[0016] According to another aspect of this application, a plasma-enhanced chemical vapor deposition system is provided, including an inlet pipe, a quartz tube, an extraction pipe, a heating furnace, a radio frequency coil, and a winding / unwinding device. The two ends of the quartz tube are respectively connected to the inlet pipe and the extraction pipe. The middle part of the quartz tube is disposed inside the heating furnace. The radio frequency coil is sleeved on the quartz tube between the inlet pipe and the heating furnace. The winding / unwinding device adopts the aforementioned winding / unwinding device. The unwinding shaft, the winding shaft, and the base are disposed inside the quartz tube inside the heating furnace. The motor is disposed outside the heating furnace.

[0017] According to one embodiment of this application, on a plane perpendicular to the axial direction of the unwinding shaft, the line connecting the axes of the unwinding shaft and the winding shaft is in line with the diameter of the quartz tube.

[0018] According to one embodiment of this application, the axis of the unwinding shaft and the axis of the winding shaft divide the diameter of the quartz tube into three equal parts.

[0019] According to one embodiment of this application, the system further includes a support frame disposed inside a quartz tube in the heating furnace, near the exhaust pipe, for auxiliary support of the winding shaft.

[0020] According to another aspect of this application, a method for preparing a graphene film is provided, employing the aforementioned plasma-enhanced chemical vapor deposition system, with the specific steps as follows:

[0021] Step 1: Place the substrate on the unwinding shaft, and fix the unwinding shaft and the take-up shaft on the base;

[0022] Step 2; Connect the substrate to the take-up shaft and wind it;

[0023] Step 3: Push the unwinding shaft, the take-up shaft, and the base into the quartz tube in the heating furnace, so that the unwinding shaft and the base are entirely located inside the quartz tube in the heating furnace, and the portion of the take-up shaft corresponding to the unwinding shaft is located inside the quartz tube in the heating furnace. Connect the end of the take-up shaft located outside the quartz tube in the heating furnace to the motor.

[0024] Step 4: Prepare graphene film. During the preparation process, the motor drives the winding shaft to wind up the substrate and the graphene film deposited on the substrate.

[0025] As can be seen from the above technical solutions, the advantages and positive effects of the graphene film winding and unwinding device, deposition system, and preparation method proposed in this application are as follows:

[0026] The graphene film unwinding and winding device proposed in this application includes a base, an unwinding shaft, a winding shaft, and a motor. A substrate is disposed on the unwinding shaft, and the graphene film is deposited and grown on the substrate to fabricate the graphene film. The winding shaft is arranged parallel to the unwinding shaft and winds up the substrate on which the graphene film is grown. The base is located below and supports the unwinding and winding shafts. During the fabrication process, the unwinding shaft, winding shaft, and base are all located within the heating zone, which avoids the width of the graphene film being limited by the diameter of the quartz tube in the heating zone, enabling the production of large-width graphene films. During the graphene film fabrication process, the unwinding shaft, winding shaft, and base are all located within the heating zone, which avoids the deposition of cold-end contaminants. Furthermore, since the unwinding shaft, winding shaft, and base can move radially inside the quartz tube in the heating zone, they can be brought closer to the radio frequency end outside the heating zone, facilitating the growth of the graphene film. The winding is performed in a region with a high plasma concentration, which is beneficial for improving plasma utilization. The motor is connected to the winding shaft, and driving the winding shaft to rotate enables the winding of a substrate with a graphene film grown on it. This application can produce large-width graphene films, avoid the deposition of cold-end contaminants, improve plasma utilization, and effectively improve the quality of graphene films. Attached Figure Description

[0027] The above and other features and advantages of this application will become more apparent from a detailed description of exemplary embodiments thereof with reference to the accompanying drawings.

[0028] Figure 1 This is a schematic diagram of the winding and unwinding device of this application.

[0029] Figure 2 yes Figure 1 A schematic diagram of the AA direction in the diagram.

[0030] Figure 3 yes Figure 1 Top view.

[0031] Figure 4 This is a schematic diagram of the plasma-enhanced chemical vapor deposition system of this application.

[0032] Figure 5 yes Figure 4 A schematic diagram of the BB-direction structure.

[0033] Figure 6 yes Figure 4 Top view.

[0034] Figure 7 This is a schematic diagram of the first type of split-type base of the winding and unwinding device of this application.

[0035] Figure 8 yes Figure 7Top view.

[0036] Figure 9 This is a top view schematic diagram of the second type of split-type base of the winding and unwinding device of this application.

[0037] Figure 10 yes Figure 9 A schematic diagram of the CC-direction structure.

[0038] The reference numerals in the attached figures are explained as follows:

[0039] 100 - Take-up and unwrap device (equipped with a substrate);

[0040] 101 - Reel;

[0041] 102 - Base;

[0042] 103 - Electric motor;

[0043] 104-substrate;

[0044] 105 - Take-up shaft bearing;

[0045] 1051 - First bearing of the winding shaft;

[0046] 1052 - Second bearing of the take-up shaft;

[0047] 106 - Rewind spool clip;

[0048] 1061 - First latch of the reel;

[0049] 1062 - Second latch of the reel;

[0050] 201 - Unwinding the reel;

[0051] 301 - Unwinding shaft bearing;

[0052] 3011 - First bearing of the unwinding shaft;

[0053] 3012 - Second bearing for unwinding shaft;

[0054] 302 - Unwinding spool clip;

[0055] 3021 - First buckle for unwinding the reel;

[0056] 3022 - Second buckle for unwinding the reel;

[0057] 401 - Intake pipe;

[0058] 402-Quartz Tube;

[0059] 403 - Extraction tube;

[0060] 404 - Heating Furnace;

[0061] 405 - Radio Frequency Coil;

[0062] 701 - First end base;

[0063] 702 - Second end base;

[0064] 605 - Installation Department;

[0065] 901 - Reel base;

[0066] 902 - Rewinding shaft base. Detailed Implementation

[0067] Typical embodiments embodying the features and advantages of this application will be described in detail in the following description. It should be understood that this application can have various variations in different embodiments, all of which do not depart from the scope of this application, and the descriptions and drawings therein are for illustrative purposes only and not intended to limit this application.

[0068] In the following description of various exemplary embodiments of this application, reference is made to the accompanying drawings, which form part of this application, and which illustrate by way of example different exemplary structures, systems, and steps that can implement various aspects of this application. It should be understood that other specific solutions to components, structures, exemplary devices, systems, and steps may be used, and structural and functional modifications may be made without departing from the scope of this application. Furthermore, while the terms “upper,” “middle,” “inner,” etc., may be used in this specification to describe different exemplary features and elements of this application, these terms are used herein only for convenience, such as the orientation according to the examples described in the accompanying drawings. Nothing in this specification should be construed as requiring a specific three-dimensional orientation of the structure to fall within the scope of this application.

[0069] To make the above-mentioned objectives, features and advantages of this application readily apparent, specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0070] like Figures 1 to 2 As shown, the unwinding and winding device 100 of this application includes an unwinding shaft 201, a winding shaft 101, a base 102, and a motor 103. A substrate 104 is disposed on the unwinding shaft 201, and a graphene film is grown on the substrate 104. The winding shaft 101 is arranged parallel to the unwinding shaft 201 and winds up the substrate 104 on which the graphene film is grown. The base 102 is disposed below the unwinding shaft 201 and the winding shaft 101 and supports the unwinding shaft 201 and the winding shaft 101. The motor 103 is connected to the winding shaft 101 and provides power to the winding shaft 101, driving the winding shaft 101 to rotate and wind up the substrate 104 on which the graphene film is grown.

[0071] In this embodiment, the unwinding shaft 201, the winding shaft 101, and the base 102 are all made of high-temperature resistant rigid materials, such as quartz, graphite, ceramic, or high-temperature resistant alloys. Since the unwinding shaft 201, the winding shaft 101, and the base 102 are constantly heated at high temperatures during the graphene film preparation process, using high-temperature resistant rigid materials can prevent deformation of the unwinding shaft 201, the winding shaft 101, and the base 102 during high-temperature heating, thus avoiding abnormal unwinding and winding during the preparation process and consequently affecting the quality of the graphene film.

[0072] In this embodiment, on a plane perpendicular to the axial direction of the unwinding shaft 201, the projection of the base 102 is a rectangle, and both the unwinding shaft 201 and the take-up shaft 101 are arranged on the same long side of the rectangle (e.g., ...). Figure 2 (As shown). In this embodiment, the projection of the base 102 can be a flat rectangle, which typically refers to a rectangle with a length-to-width ratio greater than 4:3. In some other embodiments, the projection of the base 102 on a plane perpendicular to the axial direction of the unwinding shaft 201 is a semicircle, with both the unwinding shaft 201 and the rewinding shaft 101 positioned on the diameter of the semicircle. It should be noted that the shape of the base is not limited to these; it can also be other shapes, as long as it can stably support the unwinding shaft and the rewinding shaft in the heating environment.

[0073] like Figures 1 to 3 As shown, the base 102 of the unwinding / rewinding device 100 of this application has a groove, and a bearing is provided in the groove to accommodate the unwinding shaft 201 and the take-up shaft 101 and ensure smooth rotation of the unwinding shaft 201 and the take-up shaft 101. It should be noted that the line connecting the left and right grooves accommodating the unwinding shaft 201 is parallel to the line connecting the left and right grooves accommodating the take-up shaft 101. This design ensures that the unwinding shaft 201 and the take-up shaft 101 are parallel to each other. The height of the line connecting the left and right grooves accommodating the unwinding shaft 201 and the line connecting the left and right grooves accommodating the take-up shaft 101 relative to the base 102 can be different or the same.

[0074] In this embodiment, an unwinding shaft bearing 301 is provided at the position of the unwinding shaft 201. The unwinding shaft bearing 301 includes a first unwinding shaft bearing 3011 disposed at the end away from the motor 103, and a second unwinding shaft bearing 3012 disposed at the end closer to the motor 103 (e.g., ...). Figure 3 (As shown). A take-up shaft bearing 105 is provided at the position of the take-up shaft 101, wherein the take-up shaft bearing 105 includes a first take-up shaft bearing 1051 provided at the end away from the motor 103, and a second take-up shaft bearing 1052 provided at the end closer to the motor 103.

[0075] In this embodiment, a latch is provided at both ends of each bearing corresponding to the unwinding shaft 201 and the take-up shaft 101 to fix the bearing position. Specifically, an unwinding shaft latch 302 is provided at the position of the unwinding shaft bearing 301, wherein an unwinding shaft first latch 3021 is provided at both ends of the unwinding shaft first bearing 3011; and an unwinding shaft second latch 3022 is provided at both ends of the unwinding shaft second bearing 3012. A take-up shaft latch 106 is provided at the position of the take-up shaft bearing 105, wherein a take-up shaft first latch 1061 is provided at both ends of the take-up shaft first bearing 1051; and a take-up shaft second latch 1062 is provided at both ends of the take-up shaft second bearing 1052.

[0076] In this embodiment, the length of the take-up shaft 101 is greater than the length of the unwind shaft 201, so as to connect the take-up shaft to the motor, thereby realizing the winding of the prepared graphene film.

[0077] Figures 4 to 6 A plasma-enhanced chemical vapor deposition system employing the unwinding / rewinding device 100 described above is illustrated. The system includes an inlet pipe 401, a quartz tube 402, an extraction pipe 403, a heating furnace 404, a radio frequency coil 405, and the unwinding / rewinding device 100. The two ends of the quartz tube 402 are connected to the inlet pipe 401 and the extraction pipe 402, respectively. The middle portion of the quartz tube 402 is disposed within the heating furnace 404. The radio frequency coil 405 is sleeved on the portion of the quartz tube 402 between the inlet pipe 401 and the heating furnace 404. The unwinding shaft 201, the take-up shaft 101, and the base 102 are all disposed inside the portion of the quartz tube 402 within the heating furnace 404. The motor 103 is disposed inside the portion of the quartz tube 402 outside the heating furnace 404, which is the cold end region. In this embodiment, the motor 103 is disposed at the end closer to the extraction pipe 403.

[0078] In this embodiment, the unwinding / rewinding device 100 is placed in the heating zone of the furnace 404 within the plasma-enhanced chemical vapor deposition (PECVD) system. This effectively prevents the deposition of cold-end contaminants on the substrate 104 and improves the quality of the graphene film. The unwinding / rewinding device 100 is also positioned close to the radio frequency (RF) region generated by the RF coil 405 of the PECVD system. This region has a high plasma density, which is beneficial for plasma deposition, effectively improving plasma utilization and the growth quality of the graphene film. The unwinding shaft 201, the winding shaft 101, and the base 102 of the unwinding / rewinding device 100 are all housed within the quartz tube 402 inside the heating zone, allowing for the fabrication of foils with a width larger than the inner diameter of the quartz tube in conventional PECVD systems. The length of the base 102 of the winding and unwinding device 100 of this application along the axial direction of the quartz tube 402 can be selected according to the width of the graphene film to be grown, and the width of the base 102 along the radial direction of the quartz tube 402 can be determined according to the diameter of the quartz tube in the plasma-enhanced chemical vapor deposition system.

[0079] In this embodiment, as Figure 5 As shown, on a plane perpendicular to the axial direction of the unwinding shaft 201, the line connecting the axes of the unwinding shaft 201 and the take-up shaft 101 is aligned with the diameter of the quartz tube 402. This allows for a larger distance between the axes of the unwinding shaft 201 and the take-up shaft 101, laying the foundation for achieving the maximum winding thickness.

[0080] In this embodiment, as Figure 5 As shown, the axes of the unwinding shaft 201 and the winding shaft 101 bisect the diameter of the quartz tube 402 into three equal parts. That is, the axis of the unwinding shaft 201 is exactly one-third the diameter of the quartz tube 402, and the axis of the winding shaft 101 is located at two-thirds the diameter of the quartz tube 402. This ensures that the total thickness of the maximum foil substrate 104 wound on the initial unwinding shaft 201 is two-thirds of the inner diameter of the quartz tube 402. After continuous winding, the foil substrate 104 on the unwinding shaft 201 can be fully wound onto the winding shaft 101, with a winding thickness exactly two-thirds of the inner diameter of the quartz tube 402, thus achieving the maximum winding thickness.

[0081] It should be noted that the above-mentioned design of dividing the diameter into three equal parts is a preferred design. The position of the unwinding and rewinding shafts in this application is not limited to this. The relative positions of the two shafts can be changed, which will not affect the growth of graphene, as long as the parallel arrangement and fixed relative positions of the two shafts are met.

[0082] In some other embodiments, the plasma-enhanced chemical vapor deposition system of this application also includes a support frame disposed inside the quartz tube 402 within the heating furnace 404, near the exhaust pipe 403, to assist in supporting the winding shaft 101 and ensure stable system operation. The support frame also needs to be made of a high-temperature resistant rigid material, such as quartz, graphite, ceramic, or a high-temperature resistant alloy. Since the support frame is continuously heated during the graphene film preparation process, using a high-temperature resistant rigid material can prevent deformation of the support frame, which could lead to abnormal winding and unwinding during the preparation process, thereby affecting the quality of the graphene film.

[0083] In this application, the base 102 can be integrally formed or composed of two separate structures. The two forming methods make the processing of the base more flexible, and those skilled in the art can choose according to the actual production situation.

[0084] like Figures 7 to 8 As shown, the base 102 of the unwinding / rewinding device 100 of this application includes a first end base 701 and a second end base 702. The first end base 701 supports one end of the unwinding shaft 201 and the take-up shaft 101, and the second end base 702 supports the other end of the unwinding shaft 201 and the take-up shaft 101. The height of the first end base 701 and the height of the second end base 702 are approximately the same. In this embodiment, the first end base 701 supports the end of the unwinding shaft 201 and the take-up shaft 101 away from the motor 103, and the second end base 702 supports the end of the unwinding shaft 201 and the take-up shaft 101 close to the motor 103. In some other embodiments, they can be interchanged. The split design can save materials and reduce weight, making it easier to place the entire device inside the quartz tube. In this example, the unwinding / rewinding device 100 of this application has only a split base design; the rest of the components and structure of the unwinding / rewinding device 100 are the same as in the embodiment where the base is integrally formed, and will not be described again here.

[0085] like Figures 9 to 10 As shown, the base 102 of the unwinding / rewinding device 100 of this application includes an unwinding shaft base 901 and a rewinding shaft base 902. The unwinding shaft base 901 supports the unwinding shaft 201, and the rewinding shaft base 902 supports the rewinding shaft 101. In this embodiment, the projections of the unwinding shaft base 901 and the rewinding shaft base 902 onto a plane perpendicular to the axial direction of the unwinding shaft 201 are still rectangular (e.g., ...). Figure 10As shown, the projections of the unwinding shaft base 901 and the take-up shaft base 902 onto a plane perpendicular to the axial direction of the unwinding shaft 201 form a rectangle. In this embodiment, it is a flat rectangle, which typically refers to a rectangle with a length-to-width ratio greater than 4:3. Alternatively, the projections of the unwinding shaft base 901 and the take-up shaft base 902 onto a plane perpendicular to the axial direction of the unwinding shaft 201 can form a semi-circle. In this example, the unwinding / take-up device 100 of this application has only a separate base design; the rest of the components and structure of the unwinding / take-up device 100 are the same as in the embodiment where the base is integrally formed, and will not be described again here.

[0086] It should be noted that the winding and unwinding devices shown in the accompanying drawings and described in this specification are merely a few examples among many winding and unwinding devices capable of employing the principles of this application. It should be clearly understood that the principles of this application are by no means limited to any details or components of the winding and unwinding devices shown in the accompanying drawings or described in this specification.

[0087] The above is a detailed description of several exemplary embodiments of the unwinding and take-up apparatus and plasma-enhanced chemical vapor deposition system proposed in this application. The following will provide an exemplary description of the method for preparing graphene films proposed in this application.

[0088] Combined with appendix Figures 1 to 10 The method for preparing graphene films proposed in this application employs a plasma-enhanced chemical vapor deposition apparatus with an internal winding and unwinding device 100, and the specific steps are as follows:

[0089] Step 1: Place the substrate 104 on the unwinding shaft 201, and fix the unwinding shaft 201 and the take-up shaft 101 on the base 102;

[0090] Step 2; Connect the substrate 104 to the take-up shaft 101 and wind it;

[0091] Step 3: Push the unwinding shaft 201, the take-up shaft 101, and the base 102 into the quartz tube 402 in the heating furnace 404, so that the unwinding shaft 201 and the base 102 are located inside the quartz tube 402 in the heating furnace 404, and the portion of the take-up shaft 101 corresponding to the unwinding shaft 201 is located inside the quartz tube 402 in the heating furnace 404. Connect the end of the take-up shaft 101 located outside the quartz tube 402 in the heating furnace 404 to the motor 103.

[0092] Step 4: Prepare graphene film. During the preparation process, motor 103 drives winding shaft 101 to wind up substrate 104 and graphene film deposited on substrate 104.

[0093] In this embodiment, the preparation of graphene film in step 4 can be carried out according to conventional steps in the prior art, or it can be carried out by other steps, as long as it is to prepare graphene film.

[0094] In this embodiment, the RF coil is connected to both the transmitter and ground terminals of the RF power supply. After heating, the temperature inside the quartz tube is typically 600 degrees Celsius. The protective gas can be hydrogen or argon, and the carbon source atmosphere can be methane, ethane, etc. The substrate 104 can be selected from 8 to 10 transition metals (such as Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Au) and alloys (such as Co-Ni, Au-Ni, Ni-Mo, stainless steel). The main selection criteria include the metal's melting point, carbon solubility, and the presence of stable metal carbides. These factors determine the graphene growth temperature, growth mechanism, and type of carrier gas used. Furthermore, the crystal type and orientation of the metal also affect the growth quality of the graphene.

[0095] The preparation reaction process is described in detail below, using copper foil as a substrate and methane as a carbon source atmosphere:

[0096] CH4 molecules adsorb onto the surface of a copper foil substrate. At high temperatures, the CH bonds break, producing various carbon fragments (CHx). After the methane molecules are dehydrogenated, the carbon species on the copper foil surface aggregate to form new C-C bonds and clusters, which begin to nucleate and form graphene islands. As the number of graphene nuclei on the copper foil surface increases, the carbon atoms or clusters that are subsequently generated continuously attach to the nucleation sites, causing the graphene nuclei to gradually grow until they suture together. Suturing refers to the connection that occurs between the graphene nuclei as they grow, forming larger graphene sheets, which eventually connect to form a continuous graphene film.

[0097] Through the above-described usage process of the unwinding / rewinding device and plasma-enhanced chemical vapor deposition (PECVD) apparatus of this application, as well as the graphene film preparation method, it can be concluded that the unwinding / rewinding device of this application includes an unwinding shaft, a winding shaft, and a base. The winding shaft is arranged parallel to the unwinding shaft, and the base supports the unwinding shaft and the winding shaft. By placing the unwinding shaft, winding shaft, and base within the heating zone during the preparation process, the width of the graphene film can be avoided from being limited by the diameter of the quartz tube in the heating zone, thus enabling the preparation of graphene films with a width greater than the inner diameter of the quartz tube in traditional PECVD apparatuses. Furthermore, the unwinding / rewinding device of this application, positioned within the heating zone of the PECVD apparatus during graphene film preparation, can prevent low-temperature polymerization contaminants generated by plasma overflowing to both ends of the heating zone, ensuring that the excited plasma fully generates the graphene film in the high-temperature heating zone. Finally, the unwinding / rewinding device of this application, positioned near the radio frequency region of the PECVD apparatus during graphene film preparation, can improve plasma utilization efficiency and save energy. The winding and unwinding device of this application has a simple structure, is easy to process, has a wide range of material options, is flexible and convenient to operate, has low requirements for operators, and does not require high installation precision, which is conducive to improving production efficiency and reducing costs.

[0098] In summary, the graphene film unwinding and winding device proposed in this application includes an unwinding shaft, a winding shaft, a base, and a motor. A substrate is mounted on the unwinding shaft, and the graphene film is grown on the substrate. The winding shaft is parallel to the unwinding shaft and winds up the substrate on which the graphene film is grown. The base is located below and supports the unwinding and winding shafts. The motor is connected to the winding shaft and drives its rotation to wind up the substrate on which the graphene film is grown. This unwinding and winding device is placed inside a heating furnace, which can prevent the deposition of cold-end contaminants and effectively improve the quality of the graphene film. Positioning the unwinding and winding device near the radio frequency region can improve plasma utilization. A take-up spool and an unwind spool are arranged parallel to each other and take up a substrate on which a graphene film has been grown. A base is set below the unwind spool and the take-up spool and supports them. By placing the unwind spool, the take-up spool, and the base in the heating zone during the preparation process, the width of the graphene film can be avoided by the diameter of the quartz tube in the heating zone, thus enabling the production of large-width graphene films.

[0099] The plasma-enhanced chemical vapor deposition (PECVD) system proposed in this application includes an inlet pipe, a quartz tube, an extraction pipe, a heating furnace, an RF coil, and the unwinding / winding device proposed in this application. The two ends of the quartz tube are connected to the inlet pipe and the extraction pipe, respectively. The middle part of the quartz tube is located inside the heating furnace. The RF coil is sleeved on the portion of the quartz tube between the inlet pipe and the heating furnace. The unwinding / winding device, including the unwinding shaft, the portion for winding the substrate and graphene film, and the base, are all located inside the portion of the quartz tube within the heating furnace. The motor is connected to the winding shaft and is located outside the quartz tube within the heating furnace. By placing the unwinding / winding device of this plasma-enhanced chemical vapor deposition system inside the heating furnace, the substrate is entirely positioned within the heating zone, thereby preventing the deposition of cold-end contaminants generated during the preparation process on the substrate and improving the quality of the graphene film preparation. The plasma-enhanced chemical vapor deposition system of this application has its unwinding shaft, winding shaft for winding the substrate and graphene film, and base all located inside the portion of the quartz tube within the heating furnace. Therefore, it is possible to prepare graphene films with a width greater than that of the inner diameter of the quartz tube in traditional plasma-enhanced chemical vapor deposition devices, thus solving the current problem of limited preparation of large-size graphene films.

[0100] The graphene film preparation method proposed in this application employs the aforementioned unwinding and winding device and plasma-enhanced chemical vapor deposition device. The unwinding shaft, winding shaft, and base of the unwinding and winding device, with the substrate positioned, are pushed into the quartz tube inside the heating furnace. The unwinding shaft and base are positioned entirely inside the quartz tube, while the main part of the winding shaft is located inside the quartz tube. The end of the winding shaft outside the quartz tube is connected to a motor. A protective gas is then introduced, heating is activated, and a carbon source atmosphere is introduced. Once the temperature inside the inner tube reaches the preparation temperature, the radio frequency coil is activated. The graphene film is then prepared according to conventional steps. During the preparation process, the winding wheel winds up the substrate and the graphene film deposited on the substrate. This method can prepare large-width graphene films and avoids cold-end contaminants.

[0101] The foregoing has described and / or illustrated exemplary embodiments of the unwinding and winding apparatus, plasma-enhanced chemical vapor deposition apparatus, and method for preparing graphene films according to this application. However, the embodiments of this application are not limited to the specific embodiments described herein; rather, components and / or steps of each embodiment may be used independently and separately from other components and / or steps described herein. Each component and / or step of one embodiment may also be used in combination with other components and / or steps of other embodiments. In describing the elements / components / etc. described and / or illustrated herein, the terms “a,” “first,” “second,” and “the above” are used to indicate the presence of one or more elements / components / etc. The terms “comprising,” “including,” and “having” are used to indicate an open-ended inclusion and mean that additional elements / components / etc. may exist in addition to those listed.

[0102] The embodiments of this application are not limited to the specific embodiments described herein. Rather, components of each embodiment can be used independently and separately from other components described herein. Each component of one embodiment can also be used in combination with other components of other embodiments. In the description of this specification, the terms "one embodiment," "some embodiments," "other embodiments," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the embodiments. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0103] The above are merely preferred embodiments of the application examples and are not intended to limit the application examples. For those skilled in the art, the application examples can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the application examples should be included within the protection scope of the application examples.

Claims

1. A plasma-enhanced chemical vapor deposition system for preparing graphene films, comprising: The system comprises an air inlet pipe, a quartz tube, an exhaust pipe, a heating furnace, a radio frequency coil, and a winding / unwinding device. The two ends of the quartz tube are respectively connected to the air inlet pipe and the exhaust pipe. The middle portion of the quartz tube is located inside the heating furnace. The radio frequency coil is sleeved on the quartz tube between the air inlet pipe and the heating furnace. Its characteristic is that: The aforementioned take-up and unwinding device includes: Base; An unwinding shaft is disposed on the base, the base supports the unwinding shaft, and the unwinding shaft is used to set a substrate; A take-up shaft is disposed on the base, the base supports the take-up shaft, and the take-up shaft is arranged parallel to the unwind shaft to wind up the graphene film and the substrate; An electric motor, which is connected to the take-up shaft and provides power to the take-up shaft; The unwinding shaft, the winding shaft, and the base are disposed inside the quartz tube within the heating furnace, while the motor is disposed outside the heating furnace.

2. The plasma-enhanced chemical vapor deposition system as described in claim 1, characterized in that: The unwinding shaft, the winding shaft, and the base are all made of high-temperature resistant rigid materials.

3. The plasma-enhanced chemical vapor deposition system as described in claim 1, characterized in that: On a plane perpendicular to the axial direction of the unwinding shaft, the projection of the base is a rectangle, and both the unwinding shaft and the rewinding shaft are located on the same long side of the rectangle.

4. The plasma-enhanced chemical vapor deposition system as described in claim 1, characterized in that: On a plane perpendicular to the axial direction of the unwinding shaft, the projection of the base is a semicircle, and both the unwinding shaft and the rewinding shaft are arranged on the diameter of the semicircle.

5. The plasma-enhanced chemical vapor deposition system as described in claim 1, characterized in that: The base is either a single piece or a combination of two separate structures.

6. The plasma-enhanced chemical vapor deposition system as described in claim 5, characterized in that: The base includes a first end base and a second end base. The first end base supports one end of the unwinding shaft and the rewinding shaft, and the second end base supports the other end of the unwinding shaft and the rewinding shaft.

7. The plasma-enhanced chemical vapor deposition system as described in claim 5, characterized in that: The base includes an unwinding shaft base and a rewinding shaft base, wherein the unwinding shaft is disposed on the unwinding shaft base and the rewinding shaft is disposed on the rewinding shaft base.

8. The plasma-enhanced chemical vapor deposition system as described in claim 1, characterized in that: The base is provided with a groove, and a bearing is provided in the groove. Both the unwinding shaft and the rewinding shaft are provided in the bearing, and the bearing is provided with buckles at both ends.

9. The plasma-enhanced chemical vapor deposition system as described in claim 1, characterized in that: The length of the take-up shaft is greater than the length of the unwind shaft.

10. The plasma-enhanced chemical vapor deposition system as described in claim 1, characterized in that: In a plane perpendicular to the axial direction of the unwinding shaft, the line connecting the axes of the unwinding shaft and the winding shaft is in line with the diameter of the quartz tube.

11. The plasma-enhanced chemical vapor deposition system as described in claim 10, characterized in that: The axis of the unwinding shaft and the axis of the winding shaft divide the diameter of the quartz tube into three equal parts.

12. The plasma-enhanced chemical vapor deposition system as described in claim 1, characterized in that: The system also includes a support frame, which is disposed inside the quartz tube in the heating furnace, near the exhaust pipe, to assist in supporting the winding shaft.

13. A method for preparing a graphene film, characterized in that: The plasma-enhanced chemical vapor deposition system as described in any one of claims 1-12 comprises the following specific steps: Step 1: Place the substrate on the unwinding shaft, and fix the unwinding shaft and the take-up shaft on the base; Step 2: Connect the substrate to the take-up shaft and wind it; Step 3: Push the unwinding shaft, the take-up shaft, and the base into the quartz tube in the heating furnace, so that the unwinding shaft and the base are entirely located inside the quartz tube in the heating furnace, and the portion of the take-up shaft corresponding to the unwinding shaft is located inside the quartz tube in the heating furnace. Connect the end of the take-up shaft located outside the quartz tube in the heating furnace to the motor. Step 4: Prepare graphene film. During the preparation process, the motor drives the winding shaft to wind up the substrate and the graphene film deposited on the substrate.

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