KR101630390B1 - Method for Preparing Graphene Nano Structures Using Self-Assembling Material - Google Patents

Abstract

The present invention relates to a method of manufacturing a graphene nanostructure using a self-assembled material, and more particularly, to a method of manufacturing a graphene nanostructure using a self-assembled nanostructure by forming a graphene thin film or a graphen oxide thin film on a substrate, Wherein the graphene nanostructure is produced by etching the graphene thin film or the graphen oxide thin film using a self-assembled material. The present invention also relates to a method of manufacturing a graphene nanostructure by lithography using a self-assembled material.
According to the present invention, the degree of opening of the band gap can be controlled by controlling the nanometer level of the graphene structure, which freely adjusts the electrical properties of the graphene, Therefore, an efficient method can be suggested. In addition, the method proposed in the present invention is a method capable of parallel preparation, and since self-assembling materials including block copolymers are used, mass production is easy.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for preparing a graphene nanostructure using a self-

The present invention relates to a method for manufacturing a graphene nanostructure using a self-assembled material, and more particularly, to a method for manufacturing a graphene nanostructure using a self-assembled material by forming a graphene thin film or a graphene oxide thin film on the substrate, A step of forming a graphene nano structure by etching the graphene using the assembled nanostructure as an etching mask, and removing the remaining self-assembled material mask after the graphene etching, and a lithography using a self-assembled material such as a block copolymer To a method for producing a graphene nanostructure.

Graphene is a two-dimensional monolayer structure composed of six hexagons connected to each other. The carbon nanotube has a zero-dimensional Fullerene and a tube-like one-dimensional structure. And a graphite having a three-dimensional structure. The graphene behaves like a massless Dirac fermion and shows a charge mobility of 15,000 cm ² V ^-1 s ^-1 at room temperature. The tensile strength of graphene is more than twice that of diamond and 200 to 300 times stronger than steel. Also, since graphene is a single carbon layer, it has a superior surface in transparency. Due to the outstanding electrical, mechanical and optical properties of graphene, the potential for a variety of applications is increasing.

     Various methods have been proposed for producing such graphene. Mechanical methods, chemical vapor deposition (CVD) and chemical methods have been reported as typical manufacturing methods.

     The mechanical method is to remove graphene from graphite by using Scotch tape. The size of the produced graphene is as large as several tens to several hundred micrograms, and it is possible to obtain perfect graphene without deteriorating the inherent properties of graphene. However, it has a limitation of mass production, and this method can be applied only to graphite.

     The chemical vapor deposition method is a method of forming a graphene thin film on a surface of a substrate on which a specific metal is deposited by chemically reacting gaseous components and has recently been reported in academia. In this method, graphene with relatively few defects can be obtained, but it is not only expensive to produce, but also grows graphene only in a specimen on which a specific metal is deposited, and it is necessary to transfer the grown graphene to the desired substrate again.

The chemical method is to convert graphite to oxidized graphene oxide by using a strong oxidizing agent, and then to obtain graphene from the graphen oxide by a chemical or thermal reduction method. The chemical reduction method induces a reduction reaction by adding hydrazine (N ₂ H ₄ ) or potassium hydroxide, and the thermal reduction method induces a reduction reaction by performing a high-temperature heat treatment in an atmosphere of vacuum or hydrogen gas. With this method, it is possible to mass-produce graphene of a few microns in size at a low price, and it is possible to attach another functional group or metal particles using the functional group of the graphene oxide during the process of obtaining the graphene, Do. However, the graphene produced by the chemical method has a defect that there are many defects, and the electrical property is lower than the original electrical property of the graphene.

As mentioned above, graphene has excellent optical, mechanical and electrical properties, and various applications are possible, and attempts are being made to use it as a transparent electrode. On the other hand, one of the unique properties of graphene is that the electrical characteristics are changed when nanometer sized patterned graphene is produced. It has been reported that graphene nanoribbons with very small widths of the order of a few nanometers reveal the semiconducting properties of graphenes rather than the properties of conductors which are generally visible. It is reported that the size of the band gap to be specifically formed is theoretically as follows.

Also, in the case of the Graphene Antidot Lattice type having a nanometer-sized hole continuously in a hexagonal shape, the band gap is opened like the graphene nanoribbons and the semiconducting Properties will appear. It has been reported that the bandgap of graphene antidote lethis is theoretically expected to be as follows.

Therefore, controlling graphene nanostructures through appropriate lithography methods is an area that needs to be investigated in the future to make carbon-based electronic devices.

Lithography designed to date includes photolithography, soft lithography, nanoimprint, scanning probe lithography, and scanning tunneling microscope lithography.

Photolithography is a method of forming a photoresist on a substrate by using a light source such as gline 436 nm, h-line 405 nm, i-line 365 nm, KrF 248 nm, ArF 193 nm ) Laser, deep ultraviolet (DUV) lithography using 157 nm wavelength, PXR lithography using X-ray, E-beam projection lithography using electron beam, and Extreme Ultraviolet Lithography using 13.5 nm extreme ultraviolet And then developed using a Developing Solution after exposure.

Soft lithography includes Microcontact Printing, Electrical Microcontact Printing, and Transfer Printing, which use an appropriate solution of alkanethiol as an elastomer, PDMS (Poly dimethylsiloxane) is stamped onto the ink to transfer the ink molecule to the area where the alkanethiol is applied.

     Nanoimprint is a method of thermally making the polymer layer fluid and then touching and physically pressing the patterned template to create the desired pattern on the polymer layer.

     However, with the exception of some optical lithography, most optical lithography, soft lithography, and nanoimprint lithography can be applied over a wide range, but there is a limit to the resolution of lithography, and the bandgap of graphene Gap) is open to show semiconducting properties. In the case of optical lithography to the extent that a band gap is opened, there is a disadvantage that lithography is impossible over a wide range.

The following methods have been proposed so far for ultra-fine lithography.

Scanning probe lithography is characterized in that a pattern is processed through a method of mechanically deforming a shape by applying a direct force to a surface of a sample using a micro probe.

Scanning Tunneling Microscope lithography is a scanning tunneling microscope that uses a tunneling current to induce etching on the surface of a specimen by applying a voltage that is higher than the voltage required for three dimensional measurement. . Through this method, lithography of several atomic units is possible.

However, the above method is effective in academic research because massively parallel manufacturing is impossible, but it has limitations in actual process. Although there have been no studies to date on controlling graphene nanostructures to such an extent that the band gap can be opened in parallel by the above methods, Research.

The present inventors have made intensive efforts to produce graphene nanostructures applicable to practical industrial processes. As a result, they have found that by applying a lithography process to a graphene thin film using a self-assembled nanostructure of a self-assembled material as a mask, It was confirmed that the graphene nanostructure can be manufactured and that the graphene nanostructure can freely adjust the degree of opening of the bandgap and the electrical properties, thereby completing the present invention.

It is an object of the present invention to provide a method of manufacturing a graphene nanostructure using a self-assembled material that can be applied to an actual industrial process and can freely adjust the degree of opening and electrical properties of a bandgap.

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: (a) forming a graphene thin film on a substrate; (b) forming a thin film of self-assembled material on the graphene thin film; (c) annealing the thin film of self-assembled material to form a self-assembled nanostructure; And (d) fabricating a graphene nanostructure by etching the graphene thin film using the self-assembled nanostructure formed in the step (c) as a mask to manufacture a graphene nanostructure using the self-assembled material. ≪ / RTI >

(A) forming a thin film of a graphene oxide on a substrate; (b) forming a neutral layer on the graphene oxide thin film; (c) forming a thin film of self-assembled material on the neutral layer; (d) annealing the thin film of self-assembled material to form a self-assembled nanostructure; (e) etching the graphene oxide thin film using the self-assembled nanostructure formed in the step (d) as a mask to produce a graphene oxide nanostructure; And (f) reducing the graphene oxide nanostructure to produce a graphene nanostructure. The present invention also provides a method for producing a graphene nanostructure using the self-assembled material.

(A) forming a graphene thin film on a substrate; (b) forming a PS-b-PMMA thin film on the graphene thin film; (c) heat treating the PS-b-PMMA thin film to form a cylindrical self-assembled nanostructure; And (d) etching the graphene thin film using the cylindrical self-assembled nanostructure of PS-b-PMMA formed in the step (c) as a mask to form a graphene antidote lattice The present invention provides a method for producing Graphene Antidot Lattice using PS-b-PMMA.

(A) forming a thin film of a graphene oxide on a substrate; (b) forming a neutral layer on the graphene oxide thin film; (c) forming a PS-b-PMMA thin film on the neutral layer; (d) annealing the PS-b-PMMA thin film to form a cylindrical self-assembled nanostructure; (e) fabricating a Graphene Antidot Lattice by etching the graphene oxide thin film using the cylindrical self-assembled nanostructure of PS-b-PMMA formed in step (d) as a mask ; And (f) reducing the Graphene Antidot Lattice nanostructure to produce a Graphene Antidot Lattice. The Graphene Antidot Lattice nanostructure is then reduced to produce graphene antidote lattice. (Graphene Antidot Lattice).

(A) forming a graphene thin film on a substrate; (b) forming a PS-b-PMMA thin film on the graphene thin film; (c) heat treating the PS-b-PMMA thin film to form a plate-like self-assembled nanostructure; And (d) etching the graphene thin film by using the plate-like self-assembled nanostructure of PS-b-PMMA formed in the step (c) as a mask to form a graphene nanoribbon. A method for producing a graphene nanoribbon using PS-b-PMMA is provided.

(A) forming a thin film of a graphene oxide on a substrate; (b) forming a neutral layer on the graphene oxide thin film; (c) forming a PS-b-PMMA thin film on the neutral layer; (d) heat treating the PS-b-PMMA thin film to form a plate-like self-assembled nanostructure; (e) fabricating a graphene nanoribbon by etching the graphene oxide thin film using the plate-like self-assembled nanostructure of PS-b-PMMA formed in step (d) as a mask; And (f) reducing the graphene nanoribbon nanostructure to produce a graphene nanoribbon. The graphene nanoribbon nanoparticles may be prepared by grafting nanoparticles of Graphene nanoribbon using PS-b-PMMA. And a manufacturing method thereof.

A method of manufacturing a graphene nanostructure using a self-assembled material according to the present invention includes applying a lithography process to a graphene or a graphene oxide thin film using a self-assembled nanostructure of a self-assembled material as a mask, Since the graphene nanostructure can be manufactured, the graphene nanostructure can be applied to actual industrial processes, and the graphene nanostructure can freely control the degree of opening of the band gap and the electrical properties.

FIG. 1 shows various nanostructures formed according to a composition ratio of a block of a typical double-block copolymer among self-assembled materials. FIG. 1 (a) is a state diagram in which a self-assembled nanostructure of a double-block copolymer is predicted according to a self-consistent mean field theory. FIG. 1 (b) FIG. 1 (c) shows a self-assembled nanostructure of a double-block copolymer formed according to a relative composition ratio of two blocks. FIG.
FIG. 2 is a diagram illustrating an overall process of the present invention. FIG. 2-A shows a substrate on which graphene or graphene oxide is to be deposited, and FIG. 2-B shows a step of raising graphene or graphene oxide on a desired substrate in the step (a) Represents the step of forming a self-assembled material comprising a block copolymer on graphene or graphene oxide in the above-mentioned step (b). Figure 2-D shows the selective removal of one block of the block copolymer as part of step (c) of claim 1, and Figure 2-E shows the block copolymer as part of step (c) 2F shows the self-assembled material containing the block copolymer remaining after the etching process in the step (d) of the above-mentioned first embodiment. And ultimately exhibits nano-patterned graphene or graphene oxide using self-assembled materials including block copolymers. In the figure, 1 represents graphene or graphene oxide, and 2 represents a self-assembled material including a block copolymer.
3 is a process diagram for producing a nano-patterned graphene film using a block copolymer of an embodiment according to the present invention.
FIG. 4 is a SEM photograph of Graphene Antidot Lattice prepared in Experimental Example 1. FIG.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein and the experimental methods described below are well known and commonly used in the art.

In one aspect, the present invention provides a method of manufacturing a semiconductor device, comprising: (a) forming a graphene thin film on a substrate; (b) forming a thin film of self-assembled material on the graphene thin film; (c) annealing the thin film of self-assembled material to form a self-assembled nanostructure; And (d) fabricating a graphene nanostructure by etching the graphene thin film using the self-assembled nanostructure formed in the step (c) as a mask to manufacture a graphene nanostructure using the self-assembled material. ≪ / RTI >

In the present invention, it is preferable to use a Si substrate as the substrate used for forming the nanostructure of the self-assembling material including the block copolymer, but any substrate commonly used in the art can be used without limitation.

In the present invention, the formation of the graphene thin film can be performed by a mechanical method, a chemical vapor deposition method (CVD), and a method of reducing the graphene oxide obtained by a chemical method.

In the case of graphene mechanically dropped from graphite using a tool such as a tape or the like, the mechanical method is reattached to a desired substrate, so that graphene adheres to the substrate through the van der Waals force of the graphene, .

The chemical vapor deposition (CVD) may be performed by removing the deposited metal or metal-deposited SiO ₂ layer to form graphene, and then transferring the graphene to a desired substrate. Generally, in order to form graphene by chemical vapor deposition, it is necessary to deposit a metal such as nickel (Ni), ruthenium (Ru), iridium (Ir) or copper (Cu) on the substrate before the chemical vapor deposition In which case the respective metal is dissolved in an appropriate solvent to cause the graphene to come off the metal. Reporting the current academic doegiro is nickel (Ni) metal case of the graphene produced by chemical vapor deposition from above, nitric acid (HNO ₃₎ and nickel via solvent such as a strong acid or an _{Iron (III) chloride (FeCl 3} ) , such as (Ni ) To dissolve the graphene from the metal. In addition to the method of directly removing the deposited metal, there is also a method of separating the graphene by using a multi-layer substrate which can remove the metal-deposited substrate by a specific method. Typically, when using a Si substrate with a SiO ₂ layer grown thereon, the SiO ₂ layer is melted using a buffered oxide etchant (BOE) or a hydrofluoric acid to separate the grown metal from the Si substrate , A buffered oxide etchant (BOE), or a hydrogen fluoride, the metal is melted, the graphene is floated, and finally the graphene is raised on a specific substrate. Any method of the same concept conventionally used in the art besides the above-mentioned methods can be used without limitation.

The method of reducing the graphene oxide obtained by the chemical method is a method of dispersing graphene oxide obtained through a strong oxidizing agent through water and an organic solvent and forming a thin film of a graphene oxide thin film through a solution process, And then the graphene oxide is reduced to graphene through thermal, chemical, or a mixing method thereof to obtain a graphene thin film. This method has been described in detail below.

In the present invention, the self-assembled material may be a weak intermolecular bond such as Van der walls, electrostatic interactions, hydrogen bonding and stacking interactions, And the present invention can use the self-assembled material formed as described above as a mask for etching the graphene.

In the present invention, the self-assembling material includes a block copolymer, a peptide, a virus, a protein, and the like.

In the present invention, the block copolymer is a kind of polymer material, in which two or more polymers are connected to each other through covalent bonds, and the simplest form is a double-block copolymer in which two kinds of polymers are connected Diblock Copolymer). At this time, due to the different material properties of the two polymers, they are subjected to phase separation. As a result, the domain size of the self-assembled block copolymer is as wide as 5 to 100 nm, and various types of nanostructures can be produced. (Figure 1) It is also noted that block copolymers have the ability to form more diverse, thermodynamically stable microstructures by merely adjusting the relative lengths of the two polymers, and the formation of self-assembled nanostructures as a whole , Which has been studied as a main method for forming a nanometer-sized uniform structure together with top-down techniques due to its excellent mass-production capability.

In the present invention, the block copolymer is a block copolymer in which polystyrene and a polymer other than polystyrene are covalently bonded, and the block copolymer is a polystyrene-block-poly (methylmethacrylate ), PS-b-PEO [polystyrene block-poly (ethylene oxide)], PS-b-PVP [polystyrene-block-poly (vinyl pyridine)], PS-P4VP [ B-PDMS [poly (styrene-b-dimethyl siloxane)], PS-b-PI [polystyrene-block-poly ≪ / RTI >

In the present invention, the block copolymer may have a composition ratio of a polymer other than polystyrene: polystyrene: 0.5: 0.5. In this case, the composition of the polymer other than polystyrene: polystyrene is 0.5: 0.5, A plate-like nanostructure of a copolymer is formed.

In the present invention, the composition ratio of the block copolymer other than polystyrene: polystyrene may be 0.65 to 0.60: 0.35 to 0.40 or 0.35 to 0.40: 0.65 to 0.60, wherein the polystyrene: And the composition ratio of the other polymer is 0.65 to 0.60: 0.35 to 0.40 or 0.35 to 0.40: 0.65 to 0.60, and a gyroid-type nanostructure of the block copolymer is formed.

In the present invention, the block copolymer may have a composition ratio of polystyrene: polystyrene other than that of polystyrene: 0.70 to 0.65: 0.30 to 0.35 or 0.30 to 0.35: 0.70 to 0.65, wherein the polystyrene: And the composition ratio of the other polymer is from 0.70 to 0.65: 0.30 to 0.35, or 0.30 to 0.35: 0.70 to 0.65, and a cylinder-type nanostructure of the block copolymer is formed.

In the present invention, the composition ratio of the polymer other than polystyrene: polystyrene in the block copolymer may be 0.82 to 0.77: 0.18 to 0.23 or 0.18 to 0.23: 0.82 to 0.77, wherein the polystyrene: Is 0.82 to 0.77: 0.18 to 0.23 or 0.18 to 0.23: 0.82 to 0.77, and a sphere-type nanostructure of the block copolymer is formed.

In the present invention, the peptide is a molecule in which a relatively small number of amino acids are linked by a peptide bond. The peptide includes hydrogen bonds between peptides derived from peptide bonds, types of amino acids constituting the peptide, It is self-assembled with a specific nano structure according to the number. An example of representative self-assembled peptides is that when an even number of optical isomers, L-type and D-type amino acids, alternate with each other and the nanotubes self-assemble, the inside diameter of the nanotubes is 7-8 nm , Which can be altered by controlling the number of amino acids that bind. In addition, it is known that when two phenylalanines are continuously bonded, nanowires are formed. In addition, peptides self-assembling materials are known to form various nano-sized structures depending on the type of amino acid and the number of bonds. In the case of a peptide forming a nanowire, since it has liquid crystallinity, an external force such as an electric field can be applied to control the orientation of the peptide. Therefore, in the present invention, when the nanowire-shaped peptide is formed on the graphene, the orientation of the peptide is controlled by an external force such as an electric field, and since this is used as a mask, the orientation of the graphene patterned in the nano- . Peptide self-assembling materials having various structures may be formed on the graphene, and then processed as an etching mask to form nano-sized patterned graphene.

In the present invention, self-assembling substances such as viruses and proteins are formed on the graphene in the same concept as the peptide, and then etched using the mask as a mask of the lithography process to form nano- You can make pins.

In the present invention, the self-assembled material thin film is formed by spin coating. Spin coating methods have been used in various fields of semiconductor processing for decades and have been recently developed and applied as application of thin film processes using organic materials. In general, a thin film is grown by applying a solution-like material to the center of the sample and rotating it by rotating at a high speed (about 3000 rpm or more).

In the present invention, the self-assembled monolayer material is heat-treated to induce the self-assembled nanostructure. In the case of self-assembling material, which is relatively weak to heat, such as protein, heat treatment is performed at 20 to 200 ° C for 40 to 100 hours And in the case of self-assembling materials such as other block copolymers, it is preferably performed by heating at 200 to 300 ° C for 40 to 60 hours. In the case of the block copolymer, besides the heat treatment, self-assembled nanostructure can be formed by solvent annealing. Solvent annealing induces self-assembled nanostructures using the evaporation effect of the solvent in which the self-assembled material is dissolved. The shape of the self-assembled nanostructure is determined by the type of atmospheric solvent dissolving the self-assembled material, and the humidity. For example, in the case of cylindrical PS-b-PEO dissolved in benzene in a block copolymer, a thin film is formed on the substrate by spin coating and then a benzene gas atmosphere is formed, When the swelling of the membrane is about 45% by volume and the benzene atmosphere is converted to the normal atmospheric atmosphere, the solvent can be evaporated to induce vertical alignment and high alignment of the block copolymer . At this time, if the orientation of the block copolymer is determined according to the type and the humidity of the atmospheric solvent that blows the thin film, the degree of alignment of the atmospheric solvent can be controlled over time to improve the degree of alignment.

In the present invention, a graphene nanostructure is manufactured by applying a lithography process to a graphene thin film to use the self-assembled nanostructure formed in the step (c) as a mask. The lithography is performed using a method selected from the group consisting of wet etching using a solvent that is well soluble in only one block, dry etching using a different degree of etching depending on a reactive gas, and wet etching and dry etching.

The wet etch utilizes the difference in solubility of the two blocks of the self-assembled material. One block is dissolved in the solvent and the other block is not dissolved. Therefore, when the solvent is removed, the structure of one side of the block disappears and is adsorbed to the other side of the block, and selective removal of one block of the self-assembled material becomes possible. Generally, PS-b-PMMA block copolymer can selectively remove PMMA through acetic acid. In the present invention, the organic solvent used for the selective removal of the PS-b-PMMA block copolymer is acetic acid. However, any conventional organic solvent having the same concept in the art is not limited thereto. In the case of a self-assembled material including a block copolymer other than the PS-b-PMMA block copolymer, there is no limitation as long as the wet etching is carried out with the same concept.

The dry etching is performed by using a gas such as carbon tetrafluoride (CF ₄₎ , oxygen (O ₂₎ , chlorine gas (Cl ₂ ), boron trichloride (BCl ₃ ), nitrogen gas (N ₂₎ , argon gas (Ar) He) is applied to a plasma ion of a reactive gas to collide with a substance to be etched. In this embodiment, the etching is performed by selectively removing the etching gas using a difference in etching degree of each block. In addition, a self-assembled material may be exposed to ultraviolet (UV) to maximize the difference in etch between two blocks to more selectively etch. Typical dry etching equipment includes reactive ion etching (RIE) or ion miller.

On the other hand, after the wet etching, additional dry etching may be performed to more reliably and selectively etch, thereby manufacturing a self-assembled material mask in which one block is selectively removed. In addition, when wet etching is used, etching is performed isotropically, and etching is more anisotropic when dry etching is used.

The method may further include removing the self-assembled nanostructure after the etching in the step (d). The removing method may include a method of dissolving the self-assembled material in the organic solvent and removing the self- And burning the self-assembled material through it.

The method of dissolving and removing the self-assembling material including the block copolymer in the organic solvent is a method of removing the remaining block copolymer through the organic solvent used for coating the substrate with the block copolymer thin film, . In the case of the self-assembled material other than the block copolymer, similarly to the block copolymer, the self-assembled material remaining in the well-dispersed solvent is removed. For more efficient removal, use a sonicator that can induce strong vibration in the material by using vibration of the wave.

(A) forming a thin film of a graphene oxide on a substrate; (b) forming a neutral layer on the graphene oxide thin film; (c) forming a thin film of self-assembled material on the neutral layer; (d) annealing the thin film of self-assembled material to form a self-assembled nanostructure; (e) etching the graphene oxide thin film using the self-assembled nanostructure formed in the step (d) as a mask to produce a graphene oxide nanostructure; And (f) reducing the graphene oxide nanostructure to produce a graphene nanostructure. The present invention also relates to a method for producing a graphene nanostructure using the self-assembling material.

In the present invention, since the graphene oxide is easily dispersed in a polar solvent such as water or methanol by an oxide reactor attached with graphene, it is possible to perform a solution process in producing a graphene oxide thin film, Since the graphen oxide can be easily deposited on the substrate, the graphene oxide thin film can be formed by a method selected from the group consisting of spin coating, spraying and filtration.

The spin coating method is a method in which graphene oxide is raised on a substrate by evaporating a solvent in which graphene oxide is dissolved through rotation, and is not a water but a solvent such as methanol, dimethylformamide, ethanol or acetone ), It is known that a more uniform film can be obtained when the above process is carried out.

The spray method raises the graphene oxide on the substrate by spraying a solution of the graphene oxide like a commonly used spray.

In the case of the filtration, a filter is placed and a solvent is sucked by a pump to form a uniformly stacked graphene oxide film, which is transferred to a substrate to form a graphen oxide thin film.

The concentration and amount of the well-dispersed solution controls the thickness of the graphene film produced by the above method.

The organic monolayer may be a self-assembled monolayer (SAM), a polymer brush, a polymer brush, and a metal oxide film. (Cross-linked random copolymer mat).

The self-assembled monolayer may include at least one selected from the group consisting of pentyltrichlorosilane (PETCS), phenyltrichlorosilane (PTCS), benzyltrichlorosilane (BZTCS), tolyltrichlorosilane (TTCS) 2-pyridine: PYRTMS), 4-biphenylyltrimethoxysilane (BPTMS), octadecyltrichlorosilane (Octadecyltrichlorosilane: OTS), 1-naphthyltrimehtoxysilane (NAPTMS), 1 - [(trimethoxysilyl) methyl] naphthalene (1 - [(trimethoxysilyl) methyl] naphthalene: Methyl-anthracenyl) trimethoxysilane: MANTMS). By carrying out the cleaning treatment of the solution of the organic material and then supporting the substrate in the solution, a self-assembled monolayer can be formed on the substrate, and a uniform contact angle or a block copolymer thin film is placed on the generated self-assembled monolayer The presence or absence of the self-assembled monolayer can be confirmed.

The polymer brush may be PS-random-PMMA [polystyrenerandom-poly (methylmethacrylate)]. In the present invention, the PS-r-PMMA brush may be synthesized through conventional free radical polymerization. Specifically, a polymer brush is synthesized through bulk polymerization after mixing a free radical initiator, a monomer, and a CTA (Chain Transfer Agent), and the polymer brush is mixed with graphene oxide The polymer brush layer is formed on the graphene oxide by heat treatment above. When a polymer brush is used as the neutral layer, it is possible to control the surface energy of the substrate, which is important for realizing the block copolymer nanostructure perpendicular to the substrate.

The MAT may be a benzocyclobutene-functionalized polystyrene-r-poly (methacrylate) copolymer [P (s-r-BCB-r-MMA)].

 In the present invention, the reduction of the graphene oxide is carried out by a method selected from the group consisting of a thermal reduction method, a chemical reduction method, and a mixing method thereof.

The above chemical method is a method of reacting a strong reducing agent with graphene oxide to reduce graphene oxide to graphene to obtain graphene. Hydrazine (N ₂ H ₄ ), which is commonly used in the art, can be contacted with graphene oxide in a solution state or a vapor state to obtain reduced graphene. There is also a reduction method using potassium hydroxide or the like. The chemical reduction method is not limited as long as it is a commonly used reducing agent in the art.

The thermal reduction method is a method of reducing graphene oxide by exposing it to high temperature. In order to achieve a more complete reduction process, a heat treatment in a vacuum state, a mixed gas atmosphere of hydrogen and argon, a hydrogen atmosphere and a heat treatment in an argon atmosphere were studied. In addition, studies have been carried out that the carbon material such as ethylene (C ₂ H ₄ ), etc., is more efficiently reduced when mixed with a gas containing hydrogen and argon gas and heat-treated.

On the other hand, the chemical reduction method and the thermal reduction method may be performed in parallel for more efficient reduction.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 shows various nanostructures formed according to a composition ratio of a block of a typical double-block copolymer among self-assembled materials. Various nanostructured block copolymers can be used as masks for etching, which means that various nano-structured graphenes or graphene oxides can be produced.

FIG. 1 (a) is a state diagram in which a self-assembled nanostructure of a double-block copolymer is predicted according to a self-consistent mean field theoty. FIG. 1 (b) 1 (c) shows a self-assembled nanostructure of a double-block copolymer formed according to the relative composition ratio of two blocks.

In FIG. 1 (a), Degree of Polymerization (N) is the size of the polymer, Segment Interaction is the degree of mutual reactivity between two blocks, A is the PS of the double block copolymer (PS-b-PS) And B represents the PS block of the above-mentioned double-block copolymer, and f _A and f _B represent the relative composition ratios of _A and _B , respectively. As shown in FIG. 2A, when N < 10, the block copolymer is disorderly formed, and when 10 < N < 100, f _A = N _A / (N _A + N _B ) A spherical nanostructure of a body centered cubic body surrounded by a B block substrate is formed. Further, when f _A = 0.35, the nanodomain forming the spherical shape forms a cylinder nanostructure with a hexagonal lattice, and f _A is further increased to 0.35 = f _A = 0.40 A nanostructure of a gyroid is formed in which the cylinder shapes are connected in series by two. Finally, at f _A 0.5, the nanostructure of the lamellae is formed. In this regard, when f _B = N _B / (N _A + N _B ) = 0.23, the spherical nanostructure of the body centered cubic surrounded by the A block substrate is formed. When f _B = 0.35, the nanodomain forming the spherical shape forms a cylinder nanostructure with a hexagonal lattice, and f _B is further increased to 0.35 = f _B = 0.40 A nanostructure of a gyroid is formed in which the cylinder shapes are connected in series by two. Finally, when f _B 0.5, the nanostructure of the lamellae is formed.

Fig. 1 (b) according to the present invention shows a form similar to that of Fig. 1 (a), and the result of Fig. 1 (b) according to the present invention is included in the result of Fig. It will be obvious to those skilled in the art.

FIG. 1 (c) shows the self-assembled nanostructure of the double-block copolymer formed according to the relative composition ratio of two blocks.

Figure 2 shows the overall process of the invention.

Figure 2-A shows a substrate on which graphene or graphene oxide is deposited.

FIG. 2-B shows the step of raising graphene or graphene oxide on a desired substrate in the step (a) of claim 1.

2-C is a step of forming a self-assembled material containing a block copolymer on graphene or graphene oxide by the step (b) of the above-mentioned claim 1, wherein the nanodomain of the block copolymer is formed in hexagonal lattice (Hexagonal Lattice) and a block copolymer in which a cylinder is formed. In this step, when the above-mentioned other proportion of the block copolymer is formed on the graphene or the graphen oxide, a block copolymer satisfying the respective ratios is formed likewise. In this figure, the cylinder of the block copolymer is shown as an arbitrary selection, but it is possible to use not only block copolymers having different composition ratios but also other self-assembling materials. For example, when the above-mentioned block copolymer is replaced by a ratio having a plate-like structure, a mask for obtaining graphene and graphen oxide in the form of nanoribbon is formed, and a nanowire structure A mask is formed to obtain graphene griffin oxide in the form of a nanoribbon in the same manner.

In the process of FIG. 2-C, a photoresist pattern is formed on graphene or graphene oxide using the method of Korean Patent Application No. 2008-126655 and Korean Patent Application No. 2009-0007839 proposed by the present inventor, When the block copolymer thin film is formed, the orientation and position of the block copolymer can be selectively controlled. This means that the orientation and pattern position of the graphene and the graphene oxide can be freely adjusted.

FIG. 2-D is a part of the step (c), which shows selective removal of one block of the block copolymer. This procedure may be omitted for self-assembled materials that do not need this process if they are applied only to self-assembled materials that require additional etching for use as masks, such as block copolymers.

FIG. 2-E shows a part of the step (c) in which graphene or graphen oxide is etched using a self-assembled material including a block copolymer as a mask.

FIG. 2-F shows the result of removing the self-assembled material including the remaining block copolymer after the etching process in the step (d). Finally, using the self-assembled material including the block copolymer, the nanopatterned graphene or graphen oxide . The nanopatterned graphene oxide formed in this process can be converted into nanopatterned graphene through the reduction process.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are only for illustrating the present invention and that the scope of the present invention is not construed as being limited by these embodiments.

The experiment of the example was carried out through the process of FIG.

Example 1: Preparation of nano-patterned graphene prepared through cylinder type block copolymer lithography

In order to remove impurities on the surface of the silicon (Si) substrate, the substrate was cleaned using a Piranha processing method. Here, the pyranase treatment method is carried out by immersing in a mixed solution of sulfuric acid (95 to 97%, MERCK) and hydrogen peroxide (30%, JUNSEI) at a ratio of about 7: 3 for 1 hour at 110 ° C Respectively.

The graphene oxide prepared by a chemical method was dissolved in water and a solvent of methanol (= 98.8, Sigma Aldrich) to be well dispersed, and then spin-coated on the cleaned silicon (Si) substrate. The thickness of the graphene oxide thin film is determined according to the ratio of the graphene oxide, water and methanol. In this embodiment, the graphene oxide thin film is coated twice with a solution having a mass ratio of 1: 150: 2000 to form uniform graphene oxide A film was prepared. Figure 1- (a) shows a graphene oxide film deposited on a silicon (Si) substrate.

Treated at 1000 캜 for 1 hour in hydrogen atmosphere of 100 sccm and 0.65 Torr to reduce the graphene oxide to the graphene.

The graphene thin film was spin-coated with PS-b-PMMA (polystyrene-b-poly methyl methacrylate) as a block copolymer and then heat-treated at 200 ° C for 48 hours to prepare a block copolymer thin film having self- / RTI &gt; The molecular weight of each block of the block copolymer and PS-b-PMMA was PS: PMMA = 46,000: 21,000, and the f _A of the PMMA was about 0.313.

The sample was immersed in acetic acid solution (99.7%, JUNSEI) for 5 minutes in order to selectively remove the PMMA of the block copolymer having a cylinder perpendicular to the substrate, and acetic acid was removed by immersing in tertiary distilled water for 10 minutes. A selectively removed block copolymer mask was prepared.

The specimen on which the block copolymer mask was formed was etched by RIE (Reaction Ion Etching). Oxygen was used for the RIE gas, and the power of the RF controller was 200 W and the etching process was performed for 5 seconds. The etching time can be adjusted proportionally according to the height of the graphene deposited on the cleaned silicon (Si) substrate. When the etching rate is excessively high, the block copolymer is physically and chemically reacted with the RIE gas to be removed, And the selective graphene etching process could not be carried out.

In order to remove the remaining block copolymer of the specimen prepared by the above method, the specimen was placed in toluene which is a solvent in which the block copolymer was melted, and vibration of a sonicator (JAC, ULTRASONIC, KODO, 2010) (With the device being marked HIGH), the block copolymer was detached from the substrate.

Fig. 4 shows a SEM photograph of the finally produced graphene antidertretis film. The wrinkles seen in the SEM photographs are unique structures in the formation of the graphene thin film, and it can be confirmed that the etched material is graphene.

The graphene anti-daltetes film prepared by the above method is expected to have a band gap of at least 0.1 eV, and as mentioned above, it is expected that when the etching process is continued for a longer time, it can have a larger band gap.

Example 2: Fabrication of nanopatterned graphene prepared by Lamella type block copolymer lithography

In order to remove impurities on the surface of the silicon (Si) substrate, the substrate was cleaned using a Piranha processing method. Here, the pyranase treatment method is carried out by immersing in a mixed solution of sulfuric acid (95 to 97%, MERCK) and hydrogen peroxide (30%, JUNSEI) at a ratio of about 7: 3 for 1 hour at 110 ° C Respectively.

The graphene oxide prepared by a chemical method was dissolved in water and a solvent of methanol (= 98.8, Sigma Aldrich) to be well dispersed, and then spin-coated on the cleaned silicon (Si) substrate. The thickness of the graphene oxide thin film is determined according to the ratio of the graphene oxide, water and methanol. In this embodiment, the graphene oxide thin film is coated twice with a solution having a mass ratio of 1: 150: 2000 to form uniform graphene oxide A film was prepared. Figure 1- (a) shows a graphene oxide film deposited on a silicon (Si) substrate.

Treated at 1000 캜 for 1 hour in hydrogen atmosphere of 100 sccm and 0.65 Torr to reduce the graphene oxide to the graphene.

The graphene thin film was spin-coated with PS-b-PMMA (polystyrene-b-poly methyl methacrylate) as a block copolymer and then heat-treated at 200 ° C for 48 hours to prepare a block copolymer thin film having self- / RTI &gt; The molecular weight of each block of the block copolymer and PS-b-PMMA was PS: PMMA = 48,000: 46,000, and the f _A of the PMMA was about 0.5.

RIE (Reaction Ion Etching) was used to selectively remove the PMMA of the block copolymer having a plate-like shape perpendicular to the substrate. At this time, the power of the RF controller was 50 W and the etching process was performed for 1 minute. A block copolymer mask having only selectively removed PMMA was prepared.

The specimen on which the block copolymer mask was formed was etched by RIE (Reaction Ion Etching). Oxygen was used for the RIE gas, and the power of the RF controller was 200 W and the etching process was performed for 5 seconds. The etching time can be adjusted proportionally according to the height of the graphene deposited on the cleaned silicon (Si) substrate. When the etching rate is excessively high, the block copolymer is physically and chemically reacted with the RIE gas to be removed, And the selective graphene etching process could not be carried out.

In order to remove the remaining block copolymer of the specimen prepared by the above method, the specimen was placed in toluene which is a solvent in which the block copolymer was melted, and vibration of a sonicator (JAC, ULTRASONIC, KODO, 2010) (With the device being marked HIGH), the block copolymer was detached from the substrate.

The graphene nanoribbon film prepared by the above method is expected to have a band gap of at least 0.033 eV, and as mentioned above, it is expected that if the etching process is performed for a longer time, it can have a larger band gap.

1
N (Degree of Polymerization): The size of polymer
A: Polymer block other than PS of the double block copolymer (polymer other than PS-b-PS)
B: PS block of the above-mentioned double block copolymer
f _A and f _B : a relative composition ratio of A and a relative composition ratio of B
2
1: graphene or graphene oxide
2: self-assembling material comprising block copolymer

Claims (38)

A method for producing a graphene nanostructure using a self-assembled material, comprising the steps of:
(a) forming a graphene thin film on a substrate;
(b) forming a thin film of self-assembled material on the graphene thin film;
(c) forming a self-assembled nanostructure by annealing or solvent annealing the self-assembled monolayer; And
(d) preparing a graphene nanostructure by etching the graphene thin film using the self-assembled nanostructure formed in the step (c) as a mask,
Solvent annealing determines the shape of the self-assembled nanostructure depending on the type and humidity of the atmospheric solvent that dissolves the self-assembled material.
Claim 2 has been abandoned due to the setting registration fee. The method of claim 1, wherein the graphene film of step (a) is formed by mechanical method, chemical vapor deposition (CVD), or reduction of graphene oxide obtained by a chemical method.
The method of claim 1, wherein the self-assembled material comprises a block copolymer, a peptide, a virus, or a protein.
The method according to claim 3, wherein the block copolymer is a block copolymer in which polystyrene and a polymer other than polystyrene are covalently bonded.
Claim 5 has been abandoned due to the setting registration fee. 5. The block copolymer according to claim 4, wherein the block copolymer is selected from the group consisting of PS-b-PMMA, polystyrene-block-poly (ethylene oxide) PS-b-PEP [Polystyrene-block-poly (vinyl-pyridine)], PS-P4VP [polystyrene-block- -PI [polystyrene-blockpolyisoprene] and PS-b-PDMS [poly (styrene-b-dimethyl siloxane)].
The method according to claim 4, wherein when the composition ratio of the polymer other than polystyrene: polystyrene is 0.5: 0.5, the plate-like nanostructure of the block copolymer is formed.
5. The block copolymer according to claim 4, wherein when the composition ratio of the block copolymer other than polystyrene: polystyrene is from 0.65 to 0.60: 0.35 to 0.40 or 0.35 to 0.40: 0.65 to 0.60, the gyroid- &Lt; / RTI &gt;
The method according to claim 4, wherein when the composition ratio of the polymer other than polystyrene: polystyrene in the block copolymer is 0.70 to 0.65: 0.30 to 0.35 or 0.30 to 0.35: 0.70 to 0.65, the cylinder- . &Lt; / RTI &gt;
The method of claim 4, wherein when the composition ratio of the polymer other than polystyrene: polystyrene in the block copolymer is 0.82 to 0.77: 0.18 to 0.23 or 0.18 to 0.23: 0.82 to 0.77, the spherical nanostructure of the block copolymer is . &Lt; / RTI &gt;
Claim 10 has been abandoned due to the setting registration fee. 5. The method of claim 4, wherein the block copolymer is formed by spin coating.
The method according to claim 1, wherein the heat treatment is performed at 200 to 300 캜 for 40 to 60 hours.
delete Claim 13 has been abandoned due to the set registration fee. The method of claim 1, wherein the etching is performed using a method selected from the group consisting of wet etching, dry etching, and wet and dry mixed etching.
The method of claim 1, further comprising removing self-assembled nanostructures after the etching of step (d).
A method for producing a graphene nanostructure using a self-assembled material, comprising the steps of:
(a) forming a thin film of a graphene oxide on a substrate;
(b) forming a neutral layer on the thin film of the graphene oxide;
(c) forming a thin film of self-assembled material on the neutral layer;
(d) annealing or solvent annealing the self-assembled monolayer to form a self-assembled nanostructure;
(e) etching the graphene oxide thin film using the self-assembled nanostructure formed in the step (d) as a mask to produce a graphene oxide nanostructure; And
(f) reducing the graphene oxide nanostructure to produce a graphene nanostructure.
16. The method according to claim 15, wherein the graphene oxide thin film in step (a) is formed by a chemical method selected from the group consisting of spin coating, spraying, and filtration.
16. The method of claim 15, wherein the neutral layer is an organic monolayer film or a neutral layer formed using etching.
18. The method of claim 17, wherein the organic monolayer is selected from the group consisting of a self-assembled monolayer (SAM), a polymer brush, and a cross-linked random copolymer (MAT).
19. The method of claim 18, wherein the self-assembled monolayer is selected from the group consisting of pentyltrichlorosilane (PETCS), phenyltrichlorosilane (PTCS), benzyltrichlorosilane (BZTCS), tolyltrichlorosilane (TTCS) 4-biphenylyltrimethoxysilane (BPTMS), 2 - [(trimethoxysilyl) ethyl] -2-pyridine Octadecyltrichlorosilane (OTS), 1-naphthyltrimehtoxysilane (NAPTMS), 1 - [(trimethoxysilyl) methyl] naphthalene (1 - [(trimethoxysilyl) methyl] naphthalene: MNATMS) and (9-methylanthracenyl) trimethoxysilane: MANTMS).
19. The method of claim 18, wherein the polymer brush is PS-random-PMMA.
19. The method of claim 18, wherein the cross-linked random copolymer polymer mat is a BCB-functionalized polystyrene-r-poly (methylmethacrylate) copolymer [P (Sr-BCB-r-MMA)].
16. The method of claim 15, wherein the self-assembled material comprises a block copolymer, a peptide, a virus, or a protein.
23. The method according to claim 22, wherein the block copolymer is a block copolymer in which polystyrene and a polymer other than polystyrene are covalently bonded.
Claim 24 is abandoned in setting registration fee. 24. The method of claim 23, wherein the block copolymer is selected from the group consisting of PS-b-PMMA, polystyrene-block-poly (ethylene oxide) PS-b-PEP [Polystyrene-block-poly (vinyl-pyridine)], PS-P4VP [polystyrene-block- -PI [polystyrene-blockpolyisoprene] and PS-b-PDMS [poly (styrene-b-dimethyl siloxane)]].
24. The method according to claim 23, wherein the block copolymer has a composition ratio of polystyrene: polystyrene other than 0.5: 0.5 to form a block-shaped plate-like nanostructure.
The method according to claim 23, wherein when the composition ratio of the block copolymer other than polystyrene: polystyrene is from 0.65 to 0.60: 0.35 to 0.40 or 0.35 to 0.40: 0.65 to 0.60, the gyroid-type nanostructure of the block copolymer &Lt; / RTI &gt;
The method according to claim 23, wherein when the composition ratio of the polymer other than polystyrene to polystyrene in the block copolymer is from 0.70 to 0.65: 0.30 to 0.35 or 0.30 to 0.35: 0.70 to 0.65, the cylinder-shaped nanostructure of the block copolymer . &Lt; / RTI &gt;
24. The method according to claim 23, wherein when the composition ratio of the polymer other than polystyrene: polystyrene in the block copolymer is from 0.82 to 0.77: 0.18 to 0.23 or 0.18 to 0.23: 0.82 to 0.77, the spherical nanostructure of the block copolymer . &Lt; / RTI &gt;
Claim 29 has been abandoned due to the setting registration fee. 16. The method of claim 15, wherein the thin film of self-assembled material is formed by spin coating.
16. The method of claim 15, wherein the heat treatment is performed at 200 to 300 DEG C for 40 to 60 hours.
16. The method of claim 15, wherein the solvent annealing comprises determining the shape of the self-assembled nanostructure according to the type and humidity of the atmospheric solvent dissolving the self-assembled material.
Claim 32 is abandoned due to the set registration fee. 16. The method of claim 15, wherein the etching is performed using a method selected from the group consisting of wet etching, dry etching, and wet and dry mixed etching.
Claim 33 is abandoned due to the set registration fee. 16. The method according to claim 15, wherein the reduction is carried out by a method selected from the group consisting of a thermal reduction method, a chemical reduction method, and a mixing method thereof.
16. The method of claim 15, further comprising removing self-assembled nanostructures after the etching of step (d).
Claim 35 has been abandoned due to the setting registration fee. A method for producing Graphene Antidot Lattice using PS-b-PMMA, comprising the steps of:
(a) forming a graphene thin film on a substrate;
(b) forming a PS-b-PMMA thin film having a PS: PMMA composition ratio of 0.70 to 0.65: 0.30 to 0.35 or 0.30 to 0.35: 0.70 to 0.65 on the graphene thin film;
(c) heat treating the PS-b-PMMA thin film to form a cylindrical self-assembled nanostructure; And
(d) fabricating a Graphene Antidot Lattice by etching the graphene thin film using the cylindrical self-assembled nanostructure of PS-b-PMMA formed in the step (c) as a mask.
Claim 36 is abandoned in setting registration fee. A method for producing Graphene Antidot Lattice using PS-b-PMMA, comprising the steps of:
(a) forming a thin film of a graphene oxide on a substrate;
(b) forming a neutral layer on the graphene oxide thin film;
(c) forming a PS-b-PMMA thin film on the neutral layer;
(d) annealing the PS-b-PMMA thin film to form a cylindrical self-assembled nanostructure;
(e) fabricating a Graphene Antidot Lattice by etching the graphene oxide thin film using the cylindrical self-assembled nanostructure of PS-b-PMMA formed in step (d) as a mask ; And
(f) reducing the graphene antidote lattice nanostructure to prepare a Graphene Antidot Lattice.
Claim 37 is abandoned in setting registration fee. A method for producing a graphene nanoribbon using PS-b-PMMA, comprising the steps of:
(a) forming a graphene thin film on a substrate;
(b) forming a PS-b-PMMA thin film having a PS: PMMA composition ratio of 0.5: 0.5 on the graphene thin film;
(c) heat treating the PS-b-PMMA thin film to form a plate-like self-assembled nanostructure; And
(d) fabricating a graphene nanoribbon by etching the graphene thin film using the plate-like self-assembled nanostructure of PS-b-PMMA formed in the step (c) as a mask.
Claim 38 is abandoned in setting registration fee. A method for producing a graphene nanoribbon using PS-b-PMMA, comprising the steps of:
(a) forming a thin film of a graphene oxide on a substrate;
(b) forming a neutral layer on the graphene oxide thin film;
(c) forming a PS-b-PMMA thin film on the neutral layer;
(d) heat treating the PS-b-PMMA thin film to form a plate-like self-assembled nanostructure;
(e) fabricating a graphene nanoribbon by etching the graphene oxide thin film using the plate-like self-assembled nanostructure of PS-b-PMMA formed in step (d) as a mask; And
(f) reducing the graphene nanoribbon nanostructure to produce a graphene nanoribbon.

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