Ultrafast synthesis of single-crystal, large-area, ultra-smooth monolayer graphene

Abstract

The present invention relates to a method for manufacturing single crystal graphene having a large area and extremely low surface roughness, and graphene manufactured by the manufacturing method. The method for manufacturing graphene according to the present invention comprises the steps of: (S1) introducing a metal substrate into a sealed chamber, and then heating and pressurizing the inside of the sealed chamber; (S2) supplying a gaseous carbon-containing compound into the chamber to grow graphene on the metal substrate; and (S3) cooling the chamber, wherein a first gas is continuously supplied to the sealed chamber in steps (S1) to (S3).

Description

Ultrafast synthesis of single-crystal, large-area, ultra-flat monolayer graphene

[0001] The present invention relates to a method for producing single-crystal graphene having a large area and extremely low surface roughness, and to graphene produced by the method.

[0002] Graphene is being studied for use in heat-dissipating films due to its high thermal conductivity, high durability, and excellent electrical properties. While the synthesis of high-quality graphene on metal foils using chemical vapor deposition (CVD) is widely known, the presence of wrinkles, including ripples and ripples, considered linear defects on the graphene surface, is a major factor in degrading the physical properties and performance of graphene, and extensive research is needed to address this issue.

[0003] Additionally, it has been reported that the method of producing graphene using chemical vapor deposition is not suitable for large-scale production due to the low growth rate in the range of several micrometers per minute.

[0004] Therefore, research and development is needed on a method for rapidly synthesizing large-area, defect-free graphene films.

[0005] The purpose of the present invention is to provide a method for producing large-area single-crystal ultra-flat graphene.

[0006] Another object of the present invention is to provide a method for rapidly manufacturing the large-area single crystal ultra-flat graphene.

[0007] Another object of the present invention is to provide large-area graphene having a large area, an extremely flat surface, and significantly fewer crystal defects.

[0008] The present invention provides a method for producing graphene, comprising: (S1) a step of placing a metal substrate into a sealed chamber and then heating and pressurizing the interior of the sealed chamber; (S2) a step of supplying a gaseous compound containing carbon into the chamber to grow graphene on the metal substrate; and (S3) a step of cooling the chamber; wherein a first gas is continuously supplied to the sealed chamber during steps (S1) to (S3).

[0009] In the method for manufacturing graphene according to the present invention, after the step (S3) is completed, the graphene is removed from the metal substrate, and then the steps (S1) to (S3) may be repeated.

[0010] In the method for producing graphene according to the present invention, the surface of the metal substrate may have a (111) crystal plane.

[0011] In the method for manufacturing graphene according to the present invention, the metal substrate may include nickel (Ni).

[0012] In the method for producing graphene according to the present invention, the first gas may include hydrogen (H2).

[0013] In the method for producing graphene according to the present invention, the first gas can be diluted with an inert gas.

[0014] In the method for manufacturing graphene according to the present invention, the inert gas may include argon (Ar).

[0015] In the method for manufacturing graphene according to the present invention, the hydrogen (H2) concentration of the first gas may be 10 to 90% by volume.

[0016] In the method for manufacturing graphene according to the present invention, the amount of the first gas supplied to the sealed chamber may be 10 to 500 sccm.

[0017] In the method for manufacturing graphene according to the present invention, the temperature inside the chamber due to completion of the step (S1) may be 800 to 2,000°C.

[0018] In the method for manufacturing graphene according to the present invention, the pressure inside the chamber due to completion of the step (S1) may be 5 to 80 torr.

[0019] In the method for manufacturing graphene according to the present invention, the step (S1) can be performed for 5 to 90 minutes.

[0020] In the method for producing graphene according to the present invention, the gaseous compound of step (S2) may include methane (CH4).

[0021] In the method for producing graphene according to the present invention, the gaseous compound of step (S2) can be diluted with an inert gas.

[0022] In the method for producing graphene according to the present invention, the concentration of the gaseous compound in step (S2) may be 0.1 to 10% by volume.

[0023] In the method for producing graphene according to the present invention, the amount of the gaseous compound supplied to the sealed chamber may be 0.5 to 30 sccm.

[0024] In the method for manufacturing graphene according to the present invention, the step (S2) can be performed for 30 to 300 minutes.

[0025] In the method for manufacturing graphene according to the present invention, the step (S3) can be performed for 1 second to 10 minutes.

[0026] In the method for producing graphene according to the present invention, the removal of the graphene can be performed by an electrochemical exfoliation method.

[0027] The present invention provides large-area graphene, wherein the large-area graphene is graphene manufactured by the above-described method for manufacturing graphene, and the graphene has a thickness of 250 μm. 2 10 cm inside2 It has an area of ​​, and I according to the Raman spectrum analysis of the above graphene D / I G The value is less than or equal to 0.1.

[0028] The present invention provides another large-area graphene, wherein said another large-area graphene is graphene manufactured by the above-described method for manufacturing graphene, said graphene having a particle size of 250 μm. 2 10 cm inside 2 It has an area of ​​, and the root mean square roughness (R) of the surface measured by an atomic force microscope (AFM) of the graphene q ) is less than 0.5 nm.

[0029] The present invention provides another large-area graphene, wherein said another large-area graphene is graphene manufactured by the above-described method for manufacturing graphene, said graphene having a particle size of 250 μm. 2 10 cm inside 2 It has an area of ​​, and the graphene is a single crystal.

[0030] The present invention provides a graphene manufacturing device, comprising: a sealed chamber; a substrate support positioned inside the sealed chamber; electrodes positioned at both ends of the substrate support; an energy supply unit for supplying thermal energy or electrical energy to the electrodes; a gas supply unit for supplying gas inside the sealed chamber; and a temperature measurement unit for measuring the temperature of the substrate support; wherein the substrate support is heated by energy supplied by the energy supply unit, and energy supplied by the energy supply unit is controlled according to the temperature of the substrate support measured by the temperature measurement unit.

[0031] In the graphene manufacturing device according to the present invention, the energy supplied by the energy supply unit may be electrical energy.

[0032] In the graphene manufacturing device according to the present invention, the substrate support may include metal.

[0033] In the graphene manufacturing device according to the present invention, the substrate support may include at least one element selected from the group consisting of tungsten (W), molybdenum (Mo), iridium (Ir), titanium (Ti), chromium (Cr), and carbon (C).

[0034] In the graphene manufacturing device according to the present invention, the gas supply unit can supply one or more gases containing different chemical species.

[0035] In the graphene manufacturing device according to the present invention, a gas removal unit for removing gas inside the sealed chamber may be further included.

[0036] In the graphene manufacturing device according to the present invention, the temperature uniformity of the substrate support may be 5% or less.

[0037] In the graphene manufacturing device according to the present invention, the response speed of the temperature measuring unit may be 500 ms or less.

[0038] In the graphene manufacturing device according to the present invention, the response speed of the energy supply unit controlled by the temperature of the temperature measuring unit may be 500 ms or less.

[0039] The method for producing graphene according to the present invention can produce large-area single-crystal ultra-flat graphene at a high speed.

[0040] Graphene according to the present invention can be produced with significantly fewer crystal defects, an extremely flat surface, and a very large area.

[0041] FIG. 1 is a drawing of a sealed chamber and a crucible for performing a method for manufacturing graphene according to one embodiment of the present invention, taken with an optical camera.

[0042] Figure 2 is a diagram schematically illustrating an electrochemical exfoliation method among the methods for manufacturing graphene according to one embodiment of the present invention.

[0043] FIG. 3 is a diagram schematically illustrating the temperature, pressure, and supply gas profiles of the first manufactured large-area graphene (FIG. 3 b) and the second manufactured graphene (FIG. 3 c) in a method for manufacturing graphene according to one embodiment of the present invention.

[0044] Figure 4 is a drawing (a) showing a large-area graphene according to Example 1 taken using a scanning electron microscope (SEM, 5 kV 0.8 nA, FEI verios 460) and a drawing (b) showing a large-area graphene according to Example 1 measured using an atomic force microscope (AFM, Bruker Dimension Icon system).

[0045] Figure 5 is a drawing showing the Raman spectrum of a large-area graphene according to Example 1.

[0046] Figure 6 is a drawing illustrating a large-area graphene according to Example 1 taken using an optical microscope (Zeiss AxioCam MRc5).

[0047] Figure 7 is a drawing illustrating graphene according to Example 1 taken using an atomic resolution transmission electron microscope (TEM, Titan G2 60-300, 80 kV).

[0048] Figure 8 is a drawing showing the measurement location of the transmission electron microscope selected area electron diffraction image of Figure 9.

[0049] Figure 9 is a drawing showing a transmission electron microscope selected area electron diffraction image.

[0050] FIG. 10 is a drawing showing a large-area graphene transferred over the entire area of ​​a SiO2 wafer according to Example 1, taken by an optical camera.

[0051] Figure 11 shows SEM images (a to e), optical images (f to j), and Raman I of each large-area graphene produced five times on the same metal substrate by continuously performing the production and exfoliation of large-area graphene according to one embodiment of the present invention. D / I G This is a drawing showing the mapping (k~o) measured separately.

[0052] FIG. 12 is a drawing showing a heat generation image of a metal heating element as viewed from the upper sealing mechanism (door) of a graphene manufacturing device according to one embodiment of the present invention.

[0053] FIG. 13 is a drawing illustrating a temperature profile of a substrate support portion of a graphene manufacturing device according to one embodiment of the present invention.

[0054] The embodiments described herein may be modified in various different forms, and the technology according to one embodiment is not limited to the embodiments described below. In addition, the embodiments of one embodiment are provided to more completely explain the present disclosure to a person with average knowledge in the relevant technical field. In this case, unless there is a different definition for the technical and scientific terms used, they have the meaning commonly understood by a person with ordinary skill in the technical field to which this invention belongs, and in the following description and the attached drawings, descriptions of well-known functions and configurations that may unnecessarily obscure the gist of the present invention are omitted.

[0055] Additionally, the singular forms used in this specification and the appended claims are intended to include the plural forms as well, unless the context clearly dictates otherwise.

[0056] Additionally, in this specification and the appended claims, the terms first, second, etc. are not used in a limiting sense, but are used for the purpose of distinguishing one component from another.

[0057] Additionally, in this specification and the appended claims, when a part such as a film (layer), region or component is said to be located “on,” “above,” “upper,” “lower,” “lower” or “lower” another part, this includes not only cases where one part is in contact with another part, but also cases where another part exists between the two parts.

[0058] In addition, the terms “about,” “substantially,” and the like used in this specification and the appended claims are used in a meaning that is at or close to the numerical value when manufacturing and material tolerances inherent in the meanings stated are presented, and are used to prevent unscrupulous infringers from unfairly utilizing the disclosure in which exact or absolute values ​​are mentioned in order to aid in the understanding of this specification and the appended claims.

[0059] Additionally, the numerical ranges used herein include lower and upper limits and all values ​​within that range, increments logically derived from the shape and width of the defined range, all doubly defined values, and all possible combinations of upper and lower limits of numerical ranges defined in different shapes.

[0060] Furthermore, terms such as “include” or “have” in this specification and the appended claims mean that a feature or component described in the specification is present, and unless specifically limited, do not preclude the possibility that one or more other features or components may be added.

[0061] Hereinafter, the method for manufacturing graphene and ultra-flat graphene of the present invention will be described in detail.

[0062] The present invention provides a method for producing graphene, comprising: (S1) a step of placing a metal substrate into a sealed chamber and then heating and pressurizing the interior of the sealed chamber; (S2) a step of supplying a gaseous compound containing carbon into the chamber to grow graphene on the metal substrate; and (S3) a step of cooling the chamber; wherein a first gas is continuously supplied to the sealed chamber during steps (S1) to (S3).

[0063] According to one embodiment, after the step (S3) is completed, the graphene is removed from the metal substrate, and then the steps (S1) to (S3) may be repeated. After the step (S3) is completed and the graphene is manufactured, the graphene is exfoliated, and at this time, the metal substrate is not discarded but can be used continuously by repeating the steps (S1) to (S3). When used continuously in this way, the supply of substances such as a gaseous compound containing carbon and a first gas within the chamber is continuously maintained even after the step (S3) is completed, and the graphene can be repeatedly manufactured.

[0064] According to one embodiment, the surface of the metal substrate may have a (111) crystal plane. The surface of the metal substrate may have a (111) crystal plane over the entire surface, so that the surface is extremely flat without any irregularities, and the metal included in the metal substrate is densely arranged, so that the metal may serve as a catalyst for the growth of the graphene in the (S2) step to form a single crystal. As a non-limiting example, the metal substrate may include at least one metal selected from the group consisting of nickel (111), iron (111), cobalt (111), and alloys thereof, and as an advantageous example, the metal substrate may be a nickel (111) single crystal metal.

[0065] According to one embodiment, the first gas may include hydrogen (H2). The first gas may perform the following functions: removing impurities present on the surface of the metal substrate; reducing an oxide layer on the surface of the metal substrate; controlling the growth rate of the graphene; helping the graphene grow without defects, and / or helping the carbon-containing gaseous compound to be attached / deposited on the metal substrate.

[0066] In one embodiment, the first gas may be hydrogen gas (H2), but the first gas may also be hydrogen gas diluted with an inert gas. As a non-limiting example, the first gas may be hydrogen (H2) mixed with argon (Ar).

[0067] According to one embodiment, the hydrogen (H2) concentration of the first gas may be 10 to 90% by volume. The hydrogen concentration of the first gas may be 5% by volume or more, 10% by volume or more, 30% by volume or more, or 40% by volume or more, and an upper limit may be 95% by volume or less, 90% by volume or less, 70% by volume or less, or 60% by volume or less. Specifically, the hydrogen concentration of the first gas may be 5 to 95% by volume, 10 to 90% by volume, 30 to 70% by volume, or 40 to 60% by volume. The concentration of hydrogen (H2) included in the first gas may be appropriately controlled within the above-described range to achieve the above-described effect of hydrogen while reducing side reactions.

[0068] According to one embodiment, the supply amount of the first gas supplied to the sealed chamber may be 10 to 500 sccm. The supply amount of the first gas supplied to the sealed chamber may be 10 sccm or more, 20 sccm or more, 50 sccm or more, or 100 sccm or more, and the upper limit may be 2,000 sccm or less, 1,000 sccm or less, 500 sccm or less, or 300 sccm or less. Specifically, the supply amount of the first gas supplied to the sealed chamber may be 10 to 2,000 sccm, 20 to 1,000 sccm, 50 to 500 sccm, or 100 to 300 sccm or less. As a non-limiting example, the first gas may be diluted with an inert gas, so that the amount of the first gas supplied to the sealed chamber may be 150 sccm, and at the same time, 150 sccm of argon may be supplied to the sealed chamber so that the first gas may be diluted to 50% by volume and supplied.

[0069] According to one embodiment, the temperature inside the chamber due to completion of the step (S1) may be 800 to 2,000°C. The temperature inside the chamber due to completion of the step (S1) may be 500°C or higher, 800°C or higher, or 900°C or higher, and may have an upper limit of 3,000°C or lower, 2,000°C or lower, or 1,300°C or lower. Specifically, the temperature inside the chamber due to completion of the step (S1) may be 500 to 3,000°C, 800 to 2,000°C, or 900 to 1,300°C. The step (S1) may be a step of controlling the temperature conditions of the sealed chamber immediately before performing the step (S2), and the atmosphere of the sealed chamber may be controlled to the above-described temperature range. At this time, even though the temperature of the sealed chamber may change due to the supply of the first gas in the step (S1) and / or the supply of the gaseous compound in the step (S2), the temperature of the sealed chamber can be maintained constant.

[0070] According to one embodiment, the pressure inside the chamber due to completion of the step (S1) may be 5 to 80 torr. The pressure inside the chamber due to completion of the step (S1) may be 1 torr or more, 5 torr or more, 10 torr or more, or 15 torr or more, and may have an upper limit of 100 torr or less, 80 torr or less, 50 torr or less, or 40 torr or less. Specifically, the pressure inside the chamber due to completion of the step (S1) may be 1 to 100 torr, 5 to 80 torr, 10 to 50 torr, or 15 to 40 torr. The step (S1) may be a step of controlling the pressure condition of the sealed chamber immediately before performing the step (S2), and the atmosphere of the sealed chamber may be controlled within the above-described pressure range. At this time, even though the pressure of the sealed chamber may change due to the supply of the first gas in the step (S1) and / or the supply of the gaseous compound in the step (S2), the pressure of the sealed chamber can be maintained constant.

[0071] According to one embodiment, the step (S1) may be performed for 5 to 90 minutes. The step (S1) may be performed for 1 minute or more, 5 minutes or more, 10 minutes or more, or 20 minutes or more, and may be performed for an upper limit of 180 minutes or less, 90 minutes or less, 60 minutes or less, or 30 minutes or less. Specifically, the step (S1) may be performed for 1 to 180 minutes, 5 to 90 minutes, 10 to 60 minutes, or 20 to 30 minutes. The pressurization and heating of the sealed chamber in the step (S1) may be performed within the above-described time to suppress side reactions of the metal substrate and allow the step (S2) to proceed smoothly.

[0072] According to one embodiment, the gaseous compound of the step (S2) may include methane (CH4). The carbon-containing gaseous compound of the step (S2) may include C such as methane (CH4), ethane (C2H6), and propane (C3H8). n H 2n+2 Saturated hydrocarbons satisfying; C n H 2n or C n H 2n-2 Unsaturated hydrocarbons satisfying the above; and aromatic hydrocarbons; may be selected from the group consisting of one or more. However, as an advantageous example, the gaseous compound containing carbon in the (S2) step may be selected as methane (CH4), so that the graphene can be uniformly grown with high crystallinity.

[0073] In one embodiment, the gaseous compound of step (S2) may be diluted with an inert gas. The gaseous compound may be methane gas (CH4), but may also be methane diluted with an inert gas. As a non-limiting example, the gaseous compound may be methane (CH4) mixed with argon (Ar).

[0074] According to one embodiment, the methane (CH4) concentration of the gaseous compound may be 0.1 to 10% by volume. The methane concentration of the gaseous compound may be 0.01% by volume or more, 0.05% by volume or more, 0.1% by volume or more, or 1% by volume or more, and an upper limit may be 20% by volume or less, 10% by volume or less, 5% by volume or less, or 2% by volume or less. Specifically, the methane concentration of the gaseous compound may be 0.01 to 20% by volume, 0.05 to 10% by volume, 0.1 to 5% by volume, or 1 to 2% by volume. The concentration of methane (CH4) included in the gaseous compound is appropriately controlled within the above-described range so that graphene can be uniformly grown with high crystallinity in the step (S2).

[0075] According to one embodiment, the supply amount of the gaseous compound supplied to the sealed chamber may be 0.5 to 30 sccm. The supply amount of the gaseous compound supplied to the sealed chamber may be 0.1 sccm or more, 0.5 sccm or more, 1 sccm or more, or 5 sccm or more, and an upper limit may be 100 sccm or less, 50 sccm or less, 30 sccm or less, or 10 sccm or less. Specifically, the supply amount of the gaseous compound supplied to the sealed chamber may be 0.1 to 100 sccm, 0.5 to 50 sccm, 1 to 30 sccm, or 5 to 10 sccm or less. As a non-limiting example, since the gaseous compound may be diluted with an inert gas, the supply amount of the gaseous compound supplied to the sealed chamber may be 10 sccm, and at the same time, 100 sccm of argon may be supplied to the sealed chamber so that the first gas may be diluted to 10% by volume and supplied. As another non-limiting example, the gaseous compound may be pre-diluted with argon and supplied to the sealed chamber in step (S2) to have a gaseous compound concentration of 10% by volume.

[0076] According to one embodiment, the step (S2) may be performed for 30 to 300 minutes. The step (S1) may be performed for 5 minutes or more, 10 minutes or more, 30 minutes or more, or 60 minutes or more, and may be performed for an upper limit of 1,000 minutes or less, 600 minutes or less, 300 minutes or less, or 100 minutes or less. Specifically, the step (S2) may be performed for 5 to 1,000 minutes, 10 to 600 minutes, 30 to 300 minutes, or 60 to 100 minutes. The step (S2) may be performed for the above-described time to uniformly grow the graphene with high crystallinity.

[0077] According to one embodiment, the step (S3) may be performed for 1 second to 10 minutes. The step (S3) may be a cooling step, and the cooling may be performed relatively rapidly so that the graphene is uniformly obtained with high crystallinity and no defects.

[0078] According to one embodiment, the removal of the graphene can be performed by an electrochemical exfoliation method. After the step (S3) is completed, since the metal substrate can be reused, exfoliation of the graphene positioned on the metal substrate may be required. At this time, the graphene can be exfoliated by an electrochemical exfoliation method in order to prevent deterioration and damage to the metal substrate and the graphene. As an extremely non-limiting example, the electrochemical exfoliation method may be a method in which polymethyl methacrylate (950 PMMA C4 from MicroChem) is spin-coated on the graphene at 3,000 rpm for 1 minute to provide mechanical support, and then a DC voltage (3.5 V) is applied to a PMMA / graphene / metal substrate cathode and a platinum anode of an electrolytic cell using an aqueous NaOH solution (1 M) as an electrolyte to exfoliate the graphene, and the graphene floating in the aqueous NaOH solution is transferred to another substrate, but the present invention is not limited thereto.

[0079] The present invention provides large-area graphene, wherein the large-area graphene is graphene manufactured by any one of the above-described methods for manufacturing graphene, and the graphene has a particle size of 250 μm. 2 10 cm inside 2 It has an area of ​​, and I according to the Raman spectrum analysis of the above graphene D / I G The value is less than 0.1. I according to the Raman spectrum analysis of the above graphene D / I G The value may be 5 or less, 1 or less, 0.1 or less, or 0.01 or less, and the lower limit may be 0 or more. Specifically, I according to the Raman spectrum analysis of the graphene D / IG The value can be from 0 to 5, 0 to 1, 0 to 0.1 or 0 to 0.01, and as an advantageous example, the I of the large-area graphene is as long as there is no error of the measuring device. D / I G The value can be 0.

[0080] The present invention provides large-area graphene, wherein the large-area graphene is graphene manufactured by any one of the above-described methods for manufacturing graphene, and the graphene has a particle size of 250 μm. 2 10 cm inside 2 It has an area of ​​, and the root mean square roughness (R) of the surface measured by an atomic force microscope (AFM) of the graphene q ) is less than 0.5 nm. The root mean square roughness (R) of the surface of the graphene measured by an atomic force microscope (AFM) q ) may be 5 nm or less, 2 nm or less, 1 nm or less, or 0.5 nm or less, and as a lower limit, may be 0 nm or more, 0.05 nm or more, 0.1 nm or more, or 0.2 nm or more. Specifically, the root mean square roughness (R) of the surface of the graphene measured by an atomic force microscope (AFM) q ) may be 0 to 5 nm, 0.05 to 2 nm, 0.1 to 1 nm, or 0.2 to 0.5 nm. As a non-limiting example, the large-area graphene is a single-layer, defect-free single-crystal graphene, and may have only a root mean square roughness as large as the crystal lattice of a single carbon layer. In addition, since the large-area graphene can be manufactured by the above-described method for manufacturing graphene, it may have a root mean square roughness derived from the unevenness at the atomic level of the metal substrate, and this value may be 0.22 nm.

[0081] The present invention provides large-area graphene, wherein the large-area graphene is graphene manufactured by any one of the above-described methods for manufacturing graphene, and the graphene has a particle size of 250 μm. 2 10 cm inside 2 It has an area of ​​, and the graphene is a single crystal.

[0082] In describing the various large-area graphenes according to the present invention, since each large-area graphene of the present invention can be manufactured by the above-described method for manufacturing graphene, each of the graphenes according to the present invention includes all of the contents described above in the method for manufacturing graphene.

[0083] The present invention provides a graphene manufacturing device, comprising: a sealed chamber; a substrate support positioned inside the sealed chamber; electrodes positioned at both ends of the substrate support; an energy supply unit for supplying thermal energy or electrical energy to the electrodes; a gas supply unit for supplying gas inside the sealed chamber; and a temperature measurement unit for measuring the temperature of the substrate support; wherein the substrate support is heated by energy supplied by the energy supply unit, and energy supplied by the energy supply unit is controlled according to the temperature of the substrate support measured by the temperature measurement unit.

[0084] The graphene manufacturing device according to the present invention may be a device for manufacturing the above-described large-area graphene; or a device for performing the above-described graphene manufacturing method. Accordingly, the graphene manufacturing device according to the present invention includes all of the contents described above in the graphene manufacturing method and large-area graphene.

[0085] Hereinafter, the graphene manufacturing device of the present invention will be described in more detail.

[0086] According to one embodiment, the energy supplied by the energy supply unit may be electrical energy. Specifically, the energy supply unit may be a Joule heating method in which a current is supplied to the electrode, thereby heating the substrate support unit due to the resistance of the substrate support unit. However, the present invention is not limited to the Joule heating method, and the energy supply unit may be a method in which heat is directly applied to the electrode and the substrate support unit to directly heat the substrate support unit.

[0087] According to one embodiment, the substrate support may include a metal. As described above, since the substrate support can be Joule heated, the substrate support may include a metal, and advantageously, the substrate support may be a metal. As a non-limiting example, the substrate support may include at least one element selected from the group consisting of tungsten (W), molybdenum (Mo), iridium (Ir), titanium (Ti), chromium (Cr), and carbon (C), but the present invention is not limited thereto. In this case, the carbon may form a crystalline carbon structure such as graphite, thereby forming a structure suitable for performing the Joule heating.

[0088] According to one embodiment, the gas supply unit may supply one or more gases containing different chemical species. Specifically, the gas supply unit may be a module including a first gas unit, a second gas unit, and an n-th gas unit, which supply two or more different chemical species at different rates, rather than a single supply unit.

[0089] According to one embodiment, the graphene manufacturing device may further include a gas removal unit for removing gas inside the sealed chamber. The gas removal unit may be a device for removing air inside the sealed chamber and / or gas supplied from the gas supply unit. As a non-limiting example, the gas removal unit may be a device for maintaining the sealed chamber in a low pressure or vacuum state. According to one embodiment, the temperature uniformity of the substrate support unit may be 5% or less. The temperature uniformity may be calculated from the following equation 1.

[0090] (Relationship 1)

[0091] Temperature uniformity (%) = [(T max - T min ) / T avg ] x 100%

[0092] (In relation 1, T max It means the temperature at the highest temperature point of the above substrate support, T min means the temperature at the lowest temperature point of the above substrate support, and T avg is the average temperature of the above substrate support.)

[0093] The temperature uniformity of the substrate support may be 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, or a value in a range between any two of the values ​​described herein. The substrate support may have a temperature uniformity in the above-described range so that graphene can grow with uniform orientation and crystallinity.

[0094] According to one embodiment, the response speed of the temperature measuring unit may be 500 ms or less. The response speed of the temperature measuring unit may be defined as the time taken to reach 90% of the final value of the temperature output by the temperature measuring unit when a change in the target temperature occurs. Depending on the definition of the response speed of the temperature measuring unit, the response speed of the temperature measuring unit may be 1,000 ms, 500 ms, 400 ms, 300 ms, 200 ms 100 ms, 50 ms 10 ms, 1 ms, or a value in a range between any two values ​​described herein. The response speed of the temperature measuring unit is appropriately selected within the above-described range to quickly transmit the temperature change from the energy supply unit.

[0095] According to one embodiment, the response speed of the energy supply unit controlled from the temperature of the temperature measuring unit may be 500 ms or less. The response speed of the energy supply unit may be defined as the time it takes for the energy supply unit to reach 90% of the target output value. Depending on the definition of the response speed of the energy supply unit, the response speed of the energy supply unit may be a value in a range between 1,000 ms, 500 ms, 400 ms, 300 ms, 200 ms 100 ms, 50 ms 10 ms, 1 ms, or any two values ​​described herein. The response speed of the energy supply unit is appropriately selected within the above-described range so that the operator of the graphene manufacturing device can significantly reduce the temperature deviation of the substrate support unit within the range of the target temperature value. It goes without saying that the control of the energy supply unit can be performed using a method used in the art as a control of a device, such as PID control, so that the temperature deviation of the substrate support unit can be more precisely controlled.

[0096] Hereinafter, specific examples and experimental examples will be described. However, the examples and experimental examples described below are only illustrative, and the technology described in this specification is not limited thereto.

[0097]

[0098] (Example 1)

[0099] After placing a Ni(111) metal substrate in a sealed chamber as shown in Fig. 1, the chamber was heated and pressurized until the atmosphere reached an equilibrium state of 1,050°C and 30 torr. During this time, 150 sccm of hydrogen (H2) and 150 sccm of argon (Ar) were continuously supplied to the chamber. While maintaining the temperature and pressure of the chamber, 10 sccm of 1 volume% methane (CH4) diluted with argon (Ar) was injected for 90 minutes to grow large-area graphene. Thereafter, the chamber was rapidly cooled to room temperature while continuously supplying the hydrogen, argon, and methane mixed gas to produce large-area graphene.

[0100] The large-area graphene was exfoliated using an electrochemical exfoliation method as shown in Fig. 2. Specifically, polymethyl methacrylate (950 PMMA C4 from MicroChem) was spin-coated at 3,000 rpm for 1 minute on the large-area graphene to provide mechanical support, and then a direct current voltage (3.5 V) was applied to the PMMA / graphene / metal substrate cathode and the platinum anode of an electrolytic cell using an aqueous NaOH solution (1 M) as the electrolyte to exfoliate the graphene, and the graphene floating in the aqueous NaOH solution was transferred to a SiO2-Si substrate.

[0101] Subsequently, large-area graphene was fabricated again using the same metal substrate. The temperature, pressure, and supply gas profiles of the initially fabricated large-area graphene (Fig. 3 b) and the second fabricated graphene (Fig. 3 c) are shown in Fig. 3.

[0102]

[0103] (Experimental Example 1)

[0104] A large-area graphene according to Example 1 was photographed using a scanning electron microscope (SEM, 5 kV 0.8 nA, FEI verios 460) and is shown in Fig. 4a. Referring to Fig. 4a, it was confirmed that the large-area graphene according to Example 1 was high-quality graphene without defects or wrinkles over a large area.

[0105] The large-area graphene according to Example 1 was measured using an atomic force microscope (AFM, Bruker Dimension Icon system) and is shown in Fig. 4b (topographic image), c (correlated height profile marked in b), and d (AFM amplitude error image), respectively. Referring to Fig. 4, it was confirmed that the large-area graphene according to Example 1 had a very smooth surface, and the reason for the height profile of 0.22 nm is thought to be atomic-level irregularities derived from the Ni(111) metal substrate.

[0106]

[0107] (Experimental Example 2)

[0108] The Raman spectrum of the large-area graphene according to Example 1 was measured and is shown in Fig. 5. The Raman spectrum was acquired using a Horiba LabRAM HR Evolution confocal Raman microscope using a 532 nm laser source, 10% laser power (approximately 5 mW), one accumulation, and an acquisition time of 1 second.

[0109] Figure 5b shows the I of large-area graphene according to Example 1. D / I G This is a drawing that maps the values, and the scale bar at the bottom of the drawing is 10 μm. I of large-area graphene according to Example 1 D / I GThe values ​​were close to 0 in a wide range, indicating the absence of a D band. This means that the large-area graphene according to Example 1 exhibits extremely high crystallinity.

[0110] Figure 5c is a drawing mapping the 2D band FWHM values ​​of the large-area graphene according to Example 1, and the scale bar at the bottom of the drawing is 10 μm. Referring to Figure 5c, the FWHM is about 28 cm over the entire area of ​​the large-area graphene according to Example 1. -1 This means that very flat and uniform graphene without folding or twisting was produced over a wide area.

[0111]

[0112] (Experimental Example 3)

[0113] Large-area graphene according to Example 1 was photographed using an optical microscope (Zeiss AxioCam MRc5) and is shown in Fig. 6. The scale bar in Fig. 6 is 50 μm. Similarly, it was confirmed that large-area graphene without defects was produced over a very large area.

[0114]

[0115] (Experimental Example 4)

[0116] The graphene according to Example 1 was photographed using an atomic resolution transmission electron microscope (TEM, Titan G2 60-300, 80 kV) and is shown in Fig. 7. The scale bar in Fig. 7 is 3 nm. Referring to Fig. 7, it was confirmed that the large-area graphene according to Example 1 had a perfect honeycomb shape and a perfect graphene lattice shape with no defects at all.

[0117] A transmission electron microscope selected area electron diffraction image is shown in Fig. 9. Each alphabet in Fig. 9 represents a selected area electron diffraction measurement location of the large-area graphene according to Example 1, and each measurement location is shown in Fig. 8. Referring to Fig. 9, the same orientation within about 1° was confirmed in all areas of the large-area graphene according to Example 1. Therefore, it was confirmed that the large-area graphene according to Example 1 was a single crystal over a large area.

[0118]

[0119] (Experimental Example 5)

[0120] The above Fig. 8 is a schematic diagram for indicating the location of large-area graphene. Large-area graphene transferred over the entire area of ​​a SiO2 wafer was photographed with an optical camera and is shown in Fig. 10. Referring to Figs. 8 to 10, it was confirmed that the large-area graphene according to Example 1 has a single crystal over a very wide area.

[0121]

[0122] (Experimental Example 6)

[0123] The method for producing graphene of the present invention repeatedly performs the above (S1) to (S3) and, since the metal substrate can be reused, continuously performs the production and exfoliation of large-area graphene, and large-area graphene is produced five times on the same metal substrate, and SEM images (a to e), optical images (f to j) and Raman I of each large-area graphene D / I G The mapping (k~o) was measured respectively and shown in Figure 11.

[0124] Referring to Fig. 11, it was confirmed that the metal substrate can be reused, and the quality of the large-area graphene was confirmed to be consistent even after manufacturing large-area graphene several times.

[0125]

[0126] Although the present invention has been described in this specification with specific details and limited examples, these are provided only to help a more general understanding of the present invention, and the present invention is not limited to the above examples, and those skilled in the art to which the present invention pertains can make various modifications and variations based on these descriptions. Therefore, the ideas described in this specification should not be limited to the described examples, and all things that are equivalent or equivalent to the claims below, as well as the claims, are considered to fall within the scope of the ideas described in this specification.

Claims

1. (S1) A step of placing a metal substrate into a sealed chamber and then heating and pressurizing the inside of the sealed chamber; (S2) a step of growing graphene on the metal substrate by supplying a gaseous compound containing carbon into the chamber; and (S3) a step of cooling the chamber; including; A method for producing graphene, wherein the sealed chamber is continuously supplied with a first gas in steps (S1) to (S3).

2. In paragraph 1, A method for producing graphene, wherein after the above step (S3) is completed, the graphene is removed from the metal substrate and the above steps (S1) to (S3) are repeated.

3. In paragraph 1, A method for producing graphene, wherein the surface of the above metal substrate has a (111) crystal plane.

4. In paragraph 1, A method for producing graphene, wherein the metal substrate comprises nickel (Ni).

5. In paragraph 1, A method for producing graphene, wherein the first gas comprises hydrogen (H2).

6. In paragraph 1, A method for producing graphene, wherein the first gas is diluted with an inert gas.

7. In paragraph 6, A method for producing graphene, wherein the above inert gas includes argon (Ar).

8. In paragraph 6, A method for producing graphene, wherein the hydrogen (H2) concentration of the first gas is 10 to 90% by volume.

9. In paragraph 1, A method for producing graphene, wherein the amount of the first gas supplied to the sealed chamber is 10 to 500 sccm.

10. In paragraph 1, A method for producing graphene, wherein the temperature inside the chamber is 800 to 2,000°C due to completion of the above step (S1).

11. In paragraph 1, A method for producing graphene, wherein the pressure inside the chamber is 5 to 80 torr upon completion of the above step (S1).

12. In paragraph 1, A method for producing graphene, wherein the above step (S1) is performed for 5 to 90 minutes.

13. In paragraph 1, A method for producing graphene, wherein the gaseous compound of the above (S2) step comprises methane (CH4).

14. In paragraph 1, A method for producing graphene, wherein the gaseous compound of the above step (S2) is diluted with an inert gas.

15. In paragraph 14, A method for producing graphene, wherein the concentration of the gaseous compound in the above step (S2) is 0.1 to 10% by volume.

16. In paragraph 1, A method for producing graphene, wherein the amount of the gaseous compound supplied to the sealed chamber is 0.5 to 30 sccm.

17. In paragraph 1, A method for producing graphene, wherein the above step (S2) is performed for 30 to 300 minutes.

18. In paragraph 1, A method for producing graphene, wherein the above step (S3) is performed for 1 second to 10 minutes.

19. In paragraph 2, A method for producing graphene, wherein the removal of the above graphene is performed by an electrochemical exfoliation method.

20. Graphene manufactured by the method according to any one of claims 1 to 19, The above graphene is 250 μm 2 10 cm inside 2 has an area of ​​, I according to Raman spectrum analysis of the above graphene D / I G Large-area graphene with a value of 0.1 or less.

21. Graphene manufactured by a method according to any one of claims 1 to 19, The above graphene is 250 μm 2 10 cm inside 2 has an area of ​​, The root mean square roughness (R) of the surface of the above graphene measured by an atomic force microscope (AFM) q ) is a large-area graphene with a size of less than 0.5 nm.

22. Graphene manufactured by the method according to any one of claims 1 to 19, The above graphene is 250 μm 2 10 cm inside 2 has an area of ​​, The above graphene is a single crystal, large-area graphene.

23. A sealed chamber; a substrate support portion positioned inside the sealed chamber; electrodes positioned at both ends of the substrate support portion; an energy supply portion for supplying thermal energy or electrical energy to the electrodes; a gas supply portion for supplying gas into the sealed chamber; and a temperature measurement portion for measuring the temperature of the substrate support portion; The substrate support is heated by the energy supplied by the energy supply unit, A graphene manufacturing device in which energy supplied from the energy supply unit is controlled according to the temperature of the substrate support unit measured by the temperature measuring unit.

24. In paragraph 23, A graphene manufacturing device in which the energy supplied by the above energy supply unit is electrical energy.

25. In paragraph 23, A graphene manufacturing device, wherein the substrate support comprises a metal.

26. In paragraph 25, A graphene manufacturing device, wherein the substrate support comprises at least one element selected from the group consisting of tungsten (W), molybdenum (Mo), iridium (Ir), titanium (Ti), chromium (Cr), and carbon (C).

27. In paragraph 23, A graphene manufacturing device, wherein the gas supply unit supplies one or more gases containing different chemical species.

28. In paragraph 23, A graphene manufacturing device further comprising a gas removal unit for removing gas inside the sealed chamber.

29. In paragraph 23, A graphene manufacturing device having a temperature uniformity of the substrate support of 5% or less.

30. In paragraph 23 A graphene manufacturing device, wherein the response speed of the above temperature measuring unit is 500 ms or less.

31. In paragraph 23, A graphene manufacturing device, wherein the response speed of the energy supply unit controlled by the temperature of the temperature measuring unit is 500 ms or less.

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