WO2018012864A1 - Mono-crystalline metal foil and manufacturing method therefor - Google Patents

Abstract

The present invention relates to a method of manufacturing a mono-crystalline metal foil including a step of thermally treating a poly-crystalline metal foil positioned to be spaced from a base to afford a mono-crystalline metal foil, and a mono-crystalline metal foil manufactured thereby, and can provide a mono-crystalline metal foil having a large area by thermally treating the poly-crystalline metal foil under a condition of a minimum stress applied to the poly-crystalline metal foil.

Description

Single Crystal Metal Foil, and Method of Making the Same

The present invention relates to a single crystal metal foil and a method of manufacturing the same, and more particularly, to a method for producing a large area single crystal metal foil by heat treatment under a condition that minimizes the stress applied to the polycrystalline metal foil and to a single crystal metal foil prepared therefrom It is about.

Single crystal metal refers to a material in which the entire sample is composed of single crystals having no grain boundaries, and is known to exhibit special properties compared to polycrystalline metals. Single crystal copper has been reported to have higher electrical conductivity than polycrystalline copper and silver because there is no electron scattering at the grain boundary, and in the case of single crystal superalloy, there is no grain boundary slippage, so it is excellent creep ( creep) has been reported to have resistance properties. In addition, it can be used as a catalyst for various chemical reactions such as CO oxidation and O ₂ reduction due to the uniform surface crystallization direction. In particular, recently, the use of single crystal metal as a catalyst for growth of two-dimensional nanomaterials including graphene has attracted the attention of many researchers.

Meanwhile, graphene is a two-dimensional nanomaterial with excellent charge mobility, optical transparency, mechanical strength and flexibility, and environmental resistance, and can be applied to various fields such as multifunctional nanocomposites, transparent electrode materials, and next-generation semiconductor devices. It can be a material.

Chemical vapor deposition (CVD) is widely used as a method for producing such a large area of graphene. Graphene production through CVD is a method for synthesizing graphene from a carbon-containing precursor using a transition metal catalyst layer at a high temperature.

When manufacturing graphene through CVD, it is known that graphene can exhibit the atomic structure and epitaxy growth of the transition metal layer. A commercially readily available polycrystalline transition metal layer is mainly used, but in most cases polycrystalline graphene is obtained. Polycrystalline graphene has relatively lower physical properties due to scattering and stress concentration of carriers and phonons at grain boundaries than single crystal graphene.

Therefore, in order to synthesize large area single crystal graphene, development of a method capable of forming a large area single crystal metal layer needs to be preceded.

In order to prepare a single crystal metal, epitaxial growth of the metal on the single crystal sapphire substrate through thermal evaporation, electron beam evaporation, sputter deposition, etc. Although the technology has been reported, the technology has to use an expensive single crystal substrate, there is a disadvantage that the area is limited and economical (Korean Patent Publication No. 10-2013-0020351).

Instead of forming a metal layer on an expensive single crystal substrate, a commercially available polycrystalline metal thin film is converted into a single crystal metal thin film by controlling the injection amount, injection rate, temperature, pressure, and heat treatment time of hydrogen or hydrogen-argon mixed gas. It has been reported how to (Korean Patent Publication No. 10-2014-0137301).

However, in the case of the Republic of Korea Patent Publication No. 10-2014-0137301, when the thickness of the polycrystalline copper thin film exceeds 18 ㎛, even though the heat treatment is performed under optimal conditions, grains and grain boundaries in the copper thin film remain unchanged. The remaining single crystal copper thin film could not be produced, and there was a problem that the thickness of the polycrystalline copper thin film that could be used was limited to a very narrow range of 5 to 18 µm.

In addition, when the heat treatment is performed without a substrate, as the polycrystalline copper thin film is inserted into the chamber as it is, and the heat treatment is performed while the bottom surface of the chamber and the polycrystalline copper thin film are in contact with each other, grain growth pinning around the contact portion of the copper thin film (grain growth pinning) or a stress is generated due to thermal deformation of the metal thin film by high temperature heat treatment, so that a single crystal is not effectively formed, thereby forming a polycrystalline copper thin film.

Accordingly, the present inventors have continuously studied to produce a large-area single crystal metal foil by minimizing the contact between the chamber and the polycrystalline metal foil to prevent grain growth pinning phenomenon and to suppress the stress caused by thermal deformation. Came to complete.

In order to solve the above problems, an object of the present invention is to provide a method for producing a large area single crystal metal foil by heat treatment under a condition that minimizes the stress applied to the polycrystalline metal foil and a single crystal metal foil prepared therefrom.

One aspect of the present invention for achieving the above object relates to a method for producing a single crystal metal foil comprising the step of producing a single crystal metal foil by heat-treating the polycrystalline metal foil positioned to be spaced apart from the base.

In the above aspect, the polycrystalline metal foil is fixed to the fixing portion of the polycrystalline metal foil is positioned to be spaced apart from the base, the non-fixing portion except for the fixing portion may be open, the fixing of the polycrystalline metal foil The wealth may be one or more than two.

In one aspect, the non-fixed part of the polycrystalline metal foil may be heat-treated in a straightened state.

In one embodiment, the thickness of the polycrystalline metal foil may be 5 ~ 200 ㎛, the polycrystalline metal foil is copper (Cu), nickel (Ni), cobalt (Co), iron (Fe), ruthenium (Ru) , Rhodium (Rh), palladium (Pd), platinum (Pt), silver (Ag), rhenium (Re), iridium (Ir), gold (Au), titanium (Ti), zirconium (Zr), hafnium (Hf) , Vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), aluminum (Al), zinc (Zn), manganese (Mn) or tin (Sn) foil.

In the above aspect, the single crystal metal foil may have the same crystal surface on both sides, the single crystal metal foil is (111), (001), (112), (123) or (based on the vertical direction of the plane 0001) may have a crystal plane.

In the above aspect, the heat treatment may be performed for 0.5 to 90 hours at a temperature satisfying the following relation 2 and a pressure condition of 0.0001 to 10 atm.

[Relationship 2]

0.3 × T _m ≤ T <T _m

(In relation 2, T is the heat treatment temperature (° C.), and T _m is the melting point temperature (° C.) of the metal of the polycrystalline metal foil.)

In one aspect, the heat treatment is carried out under a hydrogen gas atmosphere, argon gas atmosphere or hydrogen-argon mixed gas atmosphere, the hydrogen gas, argon gas or hydrogen-argon mixed gas may be injected at 1 to 500 sccm.

In addition, another aspect of the present invention relates to a single crystal metal foil prepared through the method for producing a single crystal metal foil described above.

Further, another aspect of the present invention relates to a single crystal metal foil having the same crystal plane on both sides.

In another aspect, the single crystal metal foil may satisfy the following Equation 1.

[Relationship 1]

95 ≤ (A _normal / A _total ) × 100

(In Equation 1, A _total is the total area of the specimen, and A _normal is the area of crystal grains having the same crystal plane with respect to the vertical plane in the specimen, except A _normal / A _total Is measured based on a specimen having a size of 2 cm × 8 cm, wherein the same crystal plane is (111), (001), (112), (123) or (0001) crystal plane.)

In addition, another aspect of the present invention is a chamber; A heating unit provided at one side of the chamber to apply heat; A gas inlet for injecting gas into the chamber; A gas outlet for discharging gas from the chamber; A pressure regulator connected to the chamber; It relates to a single crystal metal foil manufacturing apparatus comprising a; and a metal foil holder provided in the chamber. At this time, the respective devices are not greatly limited in shape, and may have various shapes and sizes.

In another aspect, the metal foil holder is to minimize the deformation of the polycrystalline metal foil generated from contact with the chamber and the holder during the heat treatment, and to maintain the polycrystalline metal foil straightened, if the shape Although not limited to a preferred example, the metal foil holder may include a metal foil fixing member provided with a rod, a forceps, or a hook ring.

In another aspect, the heating unit may be to apply heat through a furnace, resistive heating, lamp heating or induction heating, to raise to a desired temperature If so, the method is not particularly limited.

The method of manufacturing a polycrystalline metal foil according to the present invention can minimize the contact of the polycrystalline metal foil with another material by placing the polycrystalline metal foil away from the base, thereby preventing the occurrence of grain growth pinning, It is possible to effectively produce a large area single crystal metal foil by suppressing stress generation due to thermal deformation.

In addition, the base and the polycrystalline metal foils are spaced apart from each other, so that both surfaces of the polycrystalline metal foil are heat treated under the same conditions, so that single crystallization may be more effectively performed. Thus, the prepared single crystal metal foil may have the same crystal plane on both sides. have.

1 is a conceptual diagram of hanging a polycrystalline metal foil on a holder according to an embodiment of the present invention. In order to suspend the polycrystalline metal foil on the holder, one end of the metal foil was folded twice at an angle of 90 ° at 5 mm intervals so that the end of the metal foil was formed in a kind of loop so that it could be suspended on the holder.

Figure 2 (a) is a photograph of the polycrystalline copper foil before heat treatment, Figure 2 (b) is a photograph of a single crystal copper foil prepared according to an embodiment of the present invention, Figure 2 (c) is Figure 2 ( X-ray diffraction (XRD) analysis results of the P1 to P3 portion of b), Figure 2 (d) is a plane normal and in plane of the single crystal copper foil prepared in Figure 2 (b) Analysis of inverse pole figure (IPF) map of electron backscatter diffraction (EBSD).

Figure 3 (a) is a conceptual diagram of manufacturing a single crystal metal foil by heat treatment in a state in which the polycrystalline copper foil on a quartz tube according to the existing method, Figure 3 (b) is a photograph of the single crystal metal foil prepared accordingly 3 (c) is an optical photograph of a single crystal part (left) and a polycrystalline part (right), and FIG. 3 (d) is an analysis result of an EBSD IPF map of a single crystal part (left) and a polycrystalline part (right). .

Figure 4 (a) is a picture of hanging a polycrystalline metal foil on a quartz stand according to an embodiment of the present invention, Figure 4 (b) is a picture of a single crystal copper foil prepared by heat treatment, Figure 4 (c ) Is an analysis result of the EBSD IPF map for the P1 to P5 parts of FIG. 4 (b). However, in order to confirm the influence of the crystal growth on the mechanical deformation, unlike the case of FIGS. 1 and 2, the middle of the sample was artificially folded at a 45 ° angle and then heat-treated.

Figure 5 (a) is a temperature-time graph showing the heat treatment conditions according to an embodiment of the present invention, Figure 5 (b) and Figure 5 (c) is the EBSD IPF map and ODF of the copper foil according to the heat treatment conditions As a result of analyzing the change in the (orientation distribution function), (b) of FIG. 5 shows a (111) crystal plane oriented copper foil based on a vertical plane, and (c) of FIG. 5 shows a (001) crystal plane oriented copper based on a vertical plane. It forms a foil.

FIG. 6 (a) is a photograph of a single crystal copper foil having a crystal plane close to the vertical plane reference (001) manufactured according to an example of the present invention, and FIG. 6 (b) is a portion P1 to P3 of FIG. 6 (a). Analyzes of the EBSD IPF map for.

Figure 7 (a) is a photograph of a single crystal nickel foil having a vertical reference (111) crystal plane prepared according to an example of the present invention, Figure 7 (b) is a vertical reference plane (0001) crystal plane prepared according to an example 7C is a photograph of a single crystal cobalt foil, and FIG. 7C is a result of analysis of a vertical plane reference EBSD IPF map for the P1 to P3 portions of FIG. 7A, and FIG. 7D is FIG. 7B. Results of analysis of the vertical reference EBSD IPF map for the P1 to P3 portions of.

FIG. 8A illustrates a polarization optical microscope (POM) photograph of graphene coated with liquid crystal grown on a polycrystalline metal foil, and FIG. 8B illustrates a single crystal metal foil prepared according to an example of the present invention. POM image of graphene coated with liquid crystal grown on.

9 is an illustration of a single crystal metal foil manufacturing apparatus according to an embodiment of the present invention.

10 is a view schematically showing an apparatus for producing a single crystal metal foil according to one embodiment of the present invention.

(Sign of drawing)

100: chamber 200: heating part

300: gas inlet 400: gas outlet

500: pressure control unit

Hereinafter, a single crystal metal foil and a method for manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

The drawings introduced below are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below and may be embodied in other forms, and the drawings presented below may be exaggerated to clarify the spirit of the present invention. At this time, if there is no other definition in the technical terms and scientific terms used, it has a meaning commonly understood by those of ordinary skill in the art to which the present invention belongs, the gist of the present invention in the following description and the accompanying drawings Descriptions of well-known functions and configurations that may be unnecessarily blurred are omitted.

The present invention relates to a method for producing a large-area single crystal metal foil by heat treatment under a condition that minimizes the stress applied to the polycrystalline metal foil, and to a single crystal metal foil prepared therefrom.

In the conventional single crystal metal foil manufacturing method, if the thickness of the polycrystalline copper foil exceeds 18 μm, the grain and grain boundary remain in the copper foil, even though the heat treatment is performed under optimum conditions. Foils could not be produced, and there was a problem that the thickness of the available polycrystalline copper foil was limited to 5 to 18 μm, in a very narrow range.

In addition, when the heat treatment is performed without a substrate, as the polycrystalline copper foil is inserted into the chamber as it is and the heat treatment is performed while the bottom surface of the chamber and the polycrystalline copper foil are in contact with each other, grain growth pinning around the contact portion of the copper foil growth pinning) or a stress is generated due to thermal deformation of the metal foil by a high temperature heat treatment, so that the single crystal is not effectively formed, thereby forming a polycrystalline copper foil.

Accordingly, the present inventors have continuously studied to produce a large-area single crystal metal foil by minimizing the contact between the chamber and the polycrystalline metal foil to prevent grain growth pinning phenomenon and to suppress the stress caused by thermal deformation. Came to complete.

In detail, the present invention relates to a method of manufacturing a single crystal metal foil, comprising the step of producing a single crystal metal foil by heat-treating the polycrystalline metal foil positioned to be spaced apart from the base.

As such, by placing the polycrystalline metal foil away from the base, for example, the bottom or the inner surface of the chamber, it is possible to minimize the contact of the polycrystalline metal foil with other materials, thereby preventing the occurrence of grain growth pinning. In addition, it is possible to effectively produce a large-area single crystal metal foil by suppressing stress generation due to thermal deformation.

In addition, the base and the polycrystalline metal foils are spaced apart from each other, so that both surfaces of the polycrystalline metal foil are heat treated under the same conditions, so that single crystallization may be more effectively performed. Thus, the prepared single crystal metal foil may have the same crystal plane on both sides. In particular, since the single crystal metal foil may have the same crystal surface in both the in-plane and the plane normal, it is possible to produce a high quality single crystal metal foil. Specifically, the single crystal metal foil may have a (111), (001), (112), (123) or (0001) crystal plane with respect to the vertical plane.

Polycrystalline metal foil according to an embodiment of the present invention may be a portion of the polycrystalline metal foil is fixed by a specific fixing member to be positioned floating on the base. The separation distance between the base and the polycrystalline metal foil is not particularly limited, and a distance such that the polycrystalline metal foil does not come into contact with the base is sufficient.

More specifically, in the polycrystalline metal foil, the fixing part of the polycrystalline metal foil is positioned to be spaced apart from the base by being fixed by the fixing member, and the non-fixing part except the fixing part may be open. That is, other parts except for the part fixed by the fixing member may be prevented from contacting with other materials. Accordingly, the grain growth pinning phenomenon and thermal deformation caused by contact between the polycrystalline metal foil and other materials during heat treatment may be prevented. Stress can be prevented. In this case, the fixing part of the polycrystalline metal foil may be one or two or more, but preferably, the fixing part is one in terms of minimizing contact with other materials.

In particular, it is preferable to obtain a large-area single crystal metal foil in a non-fixed part except for the fixing part, that is, to heat-treat the straight portion to become a substantially single crystal metal foil. That is, the non-fixing part of the polycrystalline metal foil is preferably heat-treated in a straightened state, and when there are wrinkles or wrinkles in the non-fixing part of the polycrystalline metal foil, grain boundaries may be formed along the portion thereof. Not. In this case, the term 'straightened up' refers to a state in which the polycrystalline metal foil is completely flattened without wrinkles, wrinkles, or bends.

On the other hand, the polycrystalline metal foil according to an embodiment of the present invention may be positioned to be spaced apart from the base in the form of hanging in the gravitational direction to the fixing member, one surface of the polycrystalline metal foil suspended on the fixing member may form 80 to 90 ° with the base surface. And more preferably 90 °. Through this, it is possible to apply a uniform stress to the polycrystalline metal foil as a whole. At this time, the angle other than the right angle (90 °) is based on the acute angle formed by the base surface and one surface of the polycrystalline metal foil.

In one embodiment, as shown in the conceptual diagram shown in Figure 1 or the photo of Figure 4 (a), by folding the end of the polycrystalline metal foil in the form of a hook hangs on the cradle so that the remaining portion not in contact with the cradle is perpendicular to the base Alternatively, one end of the polycrystalline metal foil may be fixed by a fixing member to be suspended so as to be perpendicular to the base. As such, it is possible to manufacture a large-area single crystal metal foil more effectively by suspending it perpendicular to the base to minimize the contact with other materials and to apply a uniform stress to the polycrystalline metal foil as a whole.

At this time, the fixing member has no deformation under high heat treatment temperature conditions, it is preferable to use a high-temperature material that does not react with the polycrystalline metal foil, and in one embodiment, it is preferable to use a material made of a material such as quartz, alumina or zirconia. .

The shape of the fixing member is not particularly limited as long as the polycrystalline metal foil can be spaced apart from the base. In one embodiment, the fixing member may be a rod-shaped cradle as illustrated in FIG. 1, or may have one or more clamps. It may be a cradle, or a cradle having one or more hook rings, but is not necessarily limited thereto.

In one example of the present invention, it is preferable to appropriately adjust the thickness of the polycrystalline metal foil in order to more effectively monocrystallization.

In one embodiment, the thickness of the polycrystalline metal foil may be 5 ~ 200 ㎛, more preferably 10 ~ 100 ㎛. It is possible to effectively produce a single crystal metal foil in the above range. By minimizing the stress applied to the polycrystalline metal foil within such a range, the single crystal metal foil can be manufactured in a large area, and the specimen can be easily handled. If the thickness is too thin, a single crystal metal foil having a vertical reference plane (111) crystal plane may be easily produced by surface energy, but the formation of grain boundaries may increase due to an increase in stress generation due to deformation during heat treatment. On the contrary, when the thickness of the metal foil is too thick, the growth of crystal grains may be limited, and thus there may be a difficulty in manufacturing a single crystal metal foil in large areas.

The polycrystalline metal foil can be used without particular limitation as long as it is a transition metal. More specifically, for example, the polycrystalline metal foil is copper (Cu), nickel (Ni), cobalt (Co), iron (Fe), ruthenium (Ru), rhodium (Rh), palladium (Pd), platinum (Pt) , Silver (Ag), rhenium (Re), iridium (Ir), gold (Au), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta) , Chromium (Cr), molybdenum (Mo), tungsten (W), aluminum (Al), zinc (Zn), manganese (Mn), tin (Sn) foil, and the like.

For example, transition metal foils having a densely packed structure such as face centered cubic (FCC) or hexagonal close packing (HCP) have a (111) crystal plane in FCC and (0001) in HCP. Since the crystal surface has the lowest surface energy, when heat treatment is performed near the melting point of the metal under conditions where there is no additional external force such as grain growth pinning by contact with other materials and thermal stress caused by different thermal expansion coefficients, The (111) crystal plane can be spontaneously recrystallized to have a (0001) crystal plane for HCP metal to form a large area single crystal metal foil.

In one embodiment of the present invention, the heat treatment may be carried out under the heat treatment conditions of conventional metal foil, in one embodiment, the heat treatment is 0.5 to 100 hours at a temperature satisfying the following relation 2 and pressure conditions of 0.0001 to 10 atm Can be performed while.

[Relationship 2]

0.3 × T _m ≤ T <T _m

(In relation 2, T is the heat treatment temperature (° C.), and T _m is the melting point temperature (° C.) of the metal of the polycrystalline metal foil.)

Thus, by performing different heat treatment conditions according to the type of metal foil, it is possible to effectively produce a single crystal metal foil. More specifically, for example, in the case of tungsten having the highest melting point temperature of 3422 ° C., heat treatment may be performed at a temperature of about 3400 ° C. More preferably, it is preferably carried out for 10 to 60 hours at a temperature satisfying 0.6 x T _m ≤ T <T _m and a pressure condition of 0.01 to 3 atm for effectively producing a large area single crystal metal foil.

In addition, the heat treatment is preferably carried out under a hydrogen gas atmosphere, argon gas atmosphere or hydrogen-argon mixed gas atmosphere, the hydrogen gas atmosphere, argon gas atmosphere or hydrogen-argon mixed gas may be injected at 1 to 500 sccm. When injecting the hydrogen-argon mixed gas, the mixing ratio (sccm ratio) of hydrogen: argon gas may be 1: 0.1 to 10, but is not necessarily limited thereto. By performing heat treatment in a hydrogen gas atmosphere or a hydrogen-argon mixed gas atmosphere, oxidation of the metal foil can be prevented, and migration of metal atoms can be accelerated to promote crystal growth.

In addition, the present invention provides a single crystal metal foil prepared through the above-described method for producing a single crystal metal foil.

The single crystal metal foil manufactured by the above method may have the same crystal surface on both sides, and specifically, may satisfy the following Equation 1.

[Relationship 1]

95 ≤ (A _normal / A _total ) × 100

(In Equation 1, A _total is the total area of the specimen, and A _normal is the area of crystal grains having the same crystal plane with respect to the vertical plane in the specimen, except A _normal / A _total Is measured based on a specimen having a size of 2 cm × 8 cm, wherein the same crystal plane is (111), (001), (112), (123) or (0001) crystal plane.)

As mentioned above, the present invention can minimize the contact of the polycrystalline metal foil with other materials by placing the polycrystalline metal foil away from the base, for example, the inner surface of the chamber, thereby avoiding the occurrence of grain growth pinning. It is possible to prevent the occurrence of stress due to thermal deformation and to effectively produce a large area single crystal metal foil.

In addition, the base and the polycrystalline metal foils are spaced apart from each other so that both surfaces of the polycrystalline metal foil are heat treated under the same conditions, so that the single crystallization can be more effectively performed. Accordingly, the prepared single crystal metal foil has the same crystal plane on both sides. In particular, since the single crystal metal foil may have the same crystal plane in both the in-plane and the plane normal, it is possible to produce a high quality single crystal metal foil. Specifically, the single crystal metal foil may have a (111), (001), (112), (123) or (0001) crystal plane with respect to the vertical plane.

Heat treatment method for the present invention can be used a variety of methods, such as heating through a conventional furnace (resistive heating), resistive heating (resistive heating), lamp heating (ramp heating), induction heating (induction heating), the desired temperature If it can raise, it is not specifically limited to a heating method.

As such, the high-quality, large-area single crystal metal foil according to the present invention can be used without particular limitation as long as the existing polycrystalline or single crystal metal foil is used. In one embodiment, based on the excellent electrical conductivity and thermal conductivity of the single crystal metal compared to the polycrystalline metal can be used as a high-performance metal parts material throughout the electrical and electronic product field, such as printed circuit boards, heat sinks. In particular, it can provide high efficiency components suitable for the trend toward miniaturization and high integration of electrical and electronic products. In addition, the uniform surface crystallinity of the single crystal metal foil prepared by the present invention can be widely used as a catalyst for the synthesis of graphene and two-dimensional nanomaterials and various chemical reactions.

In addition, the present invention provides a single crystal metal foil manufacturing apparatus capable of manufacturing the above-mentioned single crystal metal foil.

In detail, the single crystal metal foil manufacturing apparatus according to an embodiment of the present invention the chamber 100; A heating part provided at one side of the chamber to apply heat; A gas inlet 300 for injecting gas into the chamber; A gas outlet 400 for discharging gas from the chamber; A pressure regulator 500 connected to the chamber; And a metal foil holder provided inside the chamber.

Specifically, as shown in FIG. 9 and FIG. 10 as an example of the present invention, the gas inlet 300 and the gas outlet 400 are respectively provided at both ends of the chamber 100, and the outer side of the chamber 100 is provided. A heating unit 200 capable of substantially performing heat treatment is located, and a pressure adjusting unit 500 capable of adjusting the pressure inside the chamber 100 is connected to one end of the chamber 100, and a metal foil therein. A cradle is provided.

As a more specific example, the metal foil holder is to minimize the deformation of the polycrystalline metal foil resulting from contact with the chamber 100 and the metal foil holder during heat treatment, and to maintain the polycrystalline metal foil straight, Although not particularly limited in form, as an example, as shown in FIG. 1, the metal foil holder may include a metal foil fixing member having a rod, a forceps, or a hook ring. More specifically, when the metal foil fixing member is a rod, the metal foil holder may include two pillars spaced apart from each other, and a rod physically connecting the two pillars. Alternatively, when the metal foil fixing member is a tong or a hook ring, the metal foil holder may be physically connected to the tong or hook ring on the upper surface of the chamber 100. However, the present invention is not limited thereto, and the non-fixed portion of the polycrystalline metal foil except for the fixing portion of the polycrystalline metal foil fixed by the metal foil fixing member may not come into contact with other materials such as a chamber and a metal foil holder. Of course, it can be mounted in other forms as well.

In this case, the metal foil holder has no deformation under high heat treatment temperature conditions, and it is preferable to use a high temperature material that does not react with the polycrystalline metal foil. In one embodiment, it is preferable to use a material made of a material such as quartz, alumina or zirconia. Do. In addition, when the metal foil fixing member is a rod, the rod is not particularly limited as long as it can physically connect two pillars, but preferably, the rod is horizontal to the base with respect to the longitudinal direction of the rod.

In one example of the present invention, the heating unit 200 is to increase the temperature inside the chamber to single crystallize the polycrystalline metal foil, and to raise the temperature inside the chamber 100 and the temperature of the polycrystalline metal foil to a desired temperature. It may be used without particular limitation if it is present, specifically, for example, the heating unit 200 is through a furnace (furnace), resistive heating (resistive heating), lamp heating (ramp heating) or induction heating (induction heating) It may be to apply heat.

In one embodiment of the present invention, the gas inlet 300 is for injecting a gas that can control the heat treatment atmosphere in the chamber 100 during the heat treatment, specifically, hydrogen, argon or hydrogen-argon mixed gas into the chamber The gas outlet 400 may be for discharging the hydrogen, argon or hydrogen-argon mixed gas, or the air filled in the chamber before injecting them into the chamber 100.

In one example of the present invention, the pressure control unit 500 is to give a proper control of the pressure in the chamber 100, the pressure control unit 500 is the gas inlet 300 or gas outlet 400 The pressure inside the chamber 100 can be adjusted by adjusting the amount and speed of the gas introduced or discharged through). That is, when the pressure in the chamber 100 is low, the gas may be introduced into the chamber 100 through the gas inlet 300 to increase the pressure in the chamber 100, and the pressure in the chamber 100 may be increased. When high, the gas in the chamber 100 may be discharged through the gas outlet 400 to lower the pressure in the chamber 100.

Hereinafter, a single crystal metal foil and a method for manufacturing the same according to the present invention will be described in more detail with reference to Examples. However, the following examples are only one reference for describing the present invention in detail, and the present invention is not limited thereto and may be implemented in various forms.

Also, unless defined otherwise, all technical and scientific terms have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description herein is for the purpose of effectively describing particular embodiments only and is not intended to be limiting of the invention. In addition, the unit of the additive which is not specifically described in the specification may be wt%.

Example 1

The commercially available polycrystalline copper foil was suspended in a quartz holder and heat treated as shown in FIG. 1 to prepare a single crystal copper foil having the same (111) crystal plane over the entire region of the specimen. At this time, the size of the polycrystalline copper foil specimen was 2 cm x 8 cm, the thickness was 5 ㎛.

In the heat treatment, hydrogen and argon were injected at 10 sccm, respectively, and the temperature was raised to 1050 ° C. over 2 hours at 760 torr pressure, and then maintained at 1050 ° C. for 12 hours, followed by rapid cooling.

[Examples 2 to 10]

The single crystal metal foil was prepared by varying the parameters as described in Table 1 below, and the other conditions were performed in the same manner as in Example 1. At this time, in Examples 8 and 9, as the heat treatment temperature was higher, the temperature was raised to 1350 ° C. over 3 hours.

Comparative Example 1

Heat treatment was performed under the same conditions as in Example 6, but the polycrystalline copper foil was heat-treated in a state of being placed on the bottom of a common quartz tube chamber without hanging on a holder.

First, Example 6 and Comparative Example 1 are different from the positional conditions of the polycrystalline copper foil during the heat treatment, in the case of Example 6 heat-treated by hanging the polycrystalline copper foil on the cradle to be spaced apart from the base, as shown in Figure 2 Likewise, it can be seen that a single crystal copper foil having the same (111) vertical plane and the same horizontal plane crystal plane is prepared over the entire area of the specimen (2 cm x 8 cm). In addition, as shown in FIG. 4 (b), it can be seen that the single crystal region (the area between the second and third arrows from the top) oriented in the same crystal plane has a large area of about 1 cm × 7 cm. At this time, the area between the first arrow and the second arrow from the top in Figure 4 (b) is in contact with the holder as shown in Figure 4 (a), since the polycrystalline copper foil is in contact with the quartz holder of different materials As a result, it could be confirmed that the monocrystallization failed. In addition, the portion indicated by the third arrow is a portion in which the polycrystalline copper foil is folded at a 45 ° angle, as shown in FIG. 4 (a), where stress occurs, and the grain boundaries of the folded portion and the copper foil are almost identical. This is because crystal growth is limited by the stress present in the folded portion.

Meanwhile, as shown in FIG. 3, in Comparative Example 1 in which the polycrystalline copper foil was inserted into the quartz tube chamber according to the conventional method, and both surfaces of the polycrystalline copper foil were brought into contact with the quartz tube, the heat treatment conditions other than the position conditions were different. Although all are the same, as shown in FIG. 3, more grain boundaries are formed, and it can be seen that the single crystal regions oriented in the same crystal plane are very narrow. This may be due to the occurrence of stress caused by grain growth pinning and thermal deformation due to the contact between the quartz tube and the polycrystalline copper foil. In this case, (A _normal / A _total ) is about 48%.

Next, Examples 1 to 7 look at the single crystallization characteristics by varying the thickness of the foil, and Examples 2 to 6 are similar to FIGS. 2 and 4, and have a large area over the entire portion of the sample not contacted with the quartz holder. The single crystal copper foil of was produced effectively. On the other hand, in Example 1, since the thickness of the copper foil is so thin that deformation easily occurs during heat treatment, a large number of grain boundaries were formed. In addition, in Example 7, even if the heat treatment time is increased up to 96 hours, a large number of grain boundaries exist (A _normal / A _total ) was also limited to about 10%. This is because the growth of the crystal is limited as the thickness of the foil increases.

On the other hand, Figure 5 is a result of analyzing the EBSD IPF map and ODF change of the polycrystalline copper foil with time and temperature change during heat treatment, according to the time and temperature changes from each of (b) and 5 (c) of FIG. In addition to confirming the texture change, it is shown that the crystal plane of the final single crystal copper foil varies according to the crystallographic orientation of the commercial polycrystalline copper foil itself by comparing FIGS. 5 (b) and 5 (c). You can check it. 5B is a (111) crystal plane oriented copper foil based on a vertical plane, and FIG. 5C is a (001) crystal plane oriented copper foil based on a vertical plane, and (111) crystal plane oriented copper based on a vertical plane The foil has predominantly (112), (110) textures prior to heat treatment, and the (001) crystal face oriented copper foil based on vertical planes has predominantly (112), (110), (001) textures prior to heat treatment. 6 illustrates a (001) crystal plane oriented single crystal copper foil prepared by heat-treating a polycrystalline copper foil having (112), (110), and (001) textures, and FIG. Fig. 6 (b) shows the analysis result of the EBSD IPF map for the P1 to P3 portions of Fig. 6 (a).

Example 8 is a single crystal of polycrystalline nickel foil, Example 9 is a single crystal of polycrystalline cobalt foil, as shown in Figs. 7 (a) and 7 (c), single crystal nickel having a vertical reference plane (111) crystal plane As shown in FIGS. 7B and 7D, a single crystal cobalt foil having a horizontal plane reference (0001) crystal plane was produced. However, nickel and cobalt have a higher melting point than copper, and since the self-diffusion rate of atoms is much slower, the crystal growth is limited. Therefore, rather than forming single crystals in the entire specimen like copper, they are (111) or (0001), respectively. It can be seen that the foil is formed into an aggregate of single crystals having a crystal plane.

[Production Example 1]

Graphene was grown in a conventional manner using the single crystal copper foil prepared in Example 6 as a metal catalyst layer.

The growth of graphene was first heated copper foil for 30 minutes at 1050 ℃ in an atmosphere of 20 sccm of hydrogen, and then graphene was grown by injecting 5 sccm of methane gas for 30 minutes.

FIG. 8 shows POM by coating liquid crystal on graphene grown on Preparation Example 1 and a commercial polycrystalline metal foil with liquid crystal, and confirmed the crystal direction of graphene using polarization properties of liquid crystal molecules. Since the liquid crystal molecules are oriented in the crystal direction of the graphene to exhibit polarization properties, the same color is displayed if the crystal directions of the graphene in a certain region are the same. When graphene is grown on a single crystal metal foil (FIG. 8B), the graphene is grown on a polycrystalline copper foil (FIG. 8A), and shows a more uniform color. It is close to this single crystal.

Although the present invention has been described through the specific matters and the limited embodiments as described above, it is provided only to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention belongs to Those skilled in the art can make various modifications and variations from this description.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and all the things that are equivalent to or equivalent to the claims as well as the following claims will belong to the scope of the present invention. .

Claims (16)

A method of manufacturing a single crystal metal foil, comprising the step of heat treating a polycrystalline metal foil positioned to be spaced apart from a base to produce a single crystal metal foil. The method of claim 1, The polycrystalline metal foil is a fixing portion of the polycrystalline metal foil is fixed by the fixing member and positioned to be spaced apart from the base, the non-fixing portion except for the fixing portion is a method of manufacturing a single crystal metal foil. The method of claim 2, The fixing portion of the polycrystalline metal foil is a method of producing a single crystal metal foil. The method of claim 2, The non-fixed portion of the polycrystalline metal foil is a method of producing a single crystal metal foil is heat-treated in a straightened state. The method of claim 1, The polycrystalline metal foil has a thickness of 5 ~ 200 ㎛ method of producing a single crystal metal foil. The method of claim 1, The polycrystalline metal foil is copper (Cu), nickel (Ni), cobalt (Co), iron (Fe), ruthenium (Ru), rhodium (Rh), palladium (Pd), platinum (Pt), silver (Ag), Rhenium (Re), Iridium (Ir), Gold (Au), Titanium (Ti), Zirconium (Zr), Hafnium (Hf), Vanadium (V), Niobium (Nb), Tantalum (Ta), Chromium (Cr) And molybdenum (Mo), tungsten (W), aluminum (Al), zinc (Zn), manganese (Mn) or tin (Sn) foil. The method of claim 1, The single crystal metal foil is a method for producing a single crystal metal foil having the same crystal surface on both sides. The method of claim 1, The single crystal metal foil is a method for producing a single crystal metal foil having a (111), (001), (112), (123) or (0001) crystal plane with respect to the vertical direction of the plane. The method of claim 1, The heat treatment is a method of producing a single crystal metal foil is carried out for 0.5 to 90 hours at a temperature satisfying the following relation 2 and a pressure condition of 0.0001 to 10 atm. [Relationship 2] 0.3 × T _m ≤ T <T _m (In relation 2, T is the heat treatment temperature (° C.), and T _m is the melting point temperature (° C.) of the metal of the polycrystalline metal foil.) The method of claim 1, The heat treatment is carried out under a hydrogen gas atmosphere, argon gas atmosphere or hydrogen-argon mixed gas atmosphere, the hydrogen gas, argon gas or hydrogen-argon mixed gas is injected to 1 to 500 sccm method of producing a single crystal metal foil. A single crystal metal foil manufactured by the method of manufacturing a single crystal metal foil of any one of claims 1 to 10. Single crystal metal foil having the same crystal plane on both sides. The method of claim 12, The single crystal metal foil is a single crystal metal foil that satisfies the following equation 1. [Relationship 1] 95 ≤ (A _normal / A _total ) × 100 (In Equation 1, A _total is the total area of the specimen, and A _normal is the area of crystal grains having the same crystal plane with respect to the vertical plane in the specimen, except A _normal / A _total Is measured based on a specimen having a size of 2 cm × 8 cm, wherein the same crystal plane is (111), (001), (112), (123) or (0001) crystal plane.) chamber; A heating unit provided at one side of the chamber to apply heat; A gas inlet for injecting gas into the chamber; A gas outlet for discharging gas from the chamber; A pressure regulator connected to the chamber; Single metal foil manufacturing apparatus comprising a; and a metal foil holder provided in the chamber. The method of claim 14, The metal foil holder is a single crystal metal foil manufacturing apparatus comprising a metal foil holding member provided with a rod (rod), tongs or hook hook. The method of claim 14, The heating unit is a single crystal metal foil manufacturing apparatus for applying heat through a furnace (furnace), resistive heating (resistive heating), lamp heating (ramp heating) or induction heating (induction heating).

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