KR20160089529A - Graphene transfer method and graphene transfer apparatus using vacuum heat treatment - Google Patents

Abstract

A graphene transfer method and a graphen transferring apparatus are provided. Specifically, the present invention relates to a method of manufacturing a graphene laminate, comprising the steps of: preparing a graphene laminate having a support substrate and graphene bonded thereto; and vacuum-treating the graphene laminate and the substrate to be transferred, The present invention also provides a graphene transfer method and a graphene transfer apparatus capable of performing the transfer method. By carrying out the transferring process of the graphene in a vacuum atmosphere, it is possible to transfer the graphene by maintaining the characteristics of the graphene by removing the elements causing the doping between the graphene and the substrate to be transferred. In addition, heat treatment during graphene transfer can be performed to increase the bonding force between the graphene and the substrate to be transferred, thereby improving the graphene transfer state.

Description

TECHNICAL FIELD The present invention relates to a graphene transfer method using a vacuum heat treatment and a graphen transfer apparatus using a vacuum heat treatment,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphene transfer method and a graphene transfer apparatus, and more particularly, to a graphene transfer method through vacuum heat treatment and a graphen transfer apparatus therefor.

Graphene is a layer of atoms with carbon atoms arranged in a two-dimensional honeycomb pattern. The thickness of the layer is as thin as 0.2 nm and has high physical and chemical stability. Specifically, graphene is a very promising material for next-generation electronic devices and optoelectronic devices because of its high charge transfer, excellent transparency, excellent flexibility and strength. In addition, the good bending property of graphene and high sensitivity to light can improve the efficiency of devices such as solar cells and LEDs, and can be applied to devices such as touch screens and photodetectors. The range is expanding.

Such graphene can be generally manufactured by a chemical vapor deposition (CVD) method on a metal layer. This is because graphene produced by chemical vapor deposition has the best characteristics and can be mass-produced. However, when the graphene is prepared by a chemical vapor deposition method, the graphene is first synthesized on a silicon wafer substrate or a metal substrate on which a metal catalyst layer is formed. Thus, graphene synthesized on a metal layer is transferred to a desired substrate A transfer process is required.

Generally, the graphene transferring process is a process of transferring graphene formed on a metal layer to an adhesive supporting layer (e.g., a thermal releasing tape, polydimethylsiloxane (PDMS), or polymethyl methacrylate Is transferred to a desired substrate using a known method.

However, when the graphene is transferred through such a transfer method, foreign substances are present between the graphene and the substrate due to moisture or impurities in the air during the wet etching process or graphene transfer, and the graphene transfer state is poor There are disadvantages. Further, there is a problem that the quality of the graphene is easily damaged when the device is applied with the transferred graphene because the adhesive strength between the graphene and the substrate is weak.

A problem to be solved by the present invention is to minimize the factors affecting graphene quality degradation during the graphene transferring process.

Further, the present invention is to improve the adhesion between the graphene and the substrate to improve the transferring state of the graphene.

According to one aspect of the present invention, there is provided a method of manufacturing a graphene laminate, comprising the steps of: preparing a graphene laminate having a support substrate and graphene bonded thereto; and vacuum- And transferring the pin to the transfer target substrate.

According to another aspect of the present invention, there is provided a method of manufacturing a transfer target substrate, which comprises a graphene supply unit for supplying a support substrate having a graphene disposed at one side thereof in a vacuum chamber, And a heat supply unit located below the transfer target substrate supply unit and providing heat to the transfer target substrate.

According to the present invention, the graphene transferring process is performed in a vacuum atmosphere to remove the elements that cause doping between the graphene and the transfer target substrate, thereby securing the inherent characteristics of the graphene.

Further, by transferring the graphene through the heat treatment, the bonding force between the graphene and the substrate to be transferred can be increased and the graphene transferring state can be improved.

1 is a flow chart showing a transfer method of graphene according to an embodiment of the present invention.
2 is a schematic diagram of a graphen transfer apparatus according to an embodiment of the present invention.
3 is a schematic diagram of a graphen transfer apparatus according to another embodiment of the present invention.
4 is a schematic diagram of a graphen transfer apparatus according to another embodiment of the present invention.
5 is a schematic diagram of a graphen transfer apparatus according to another embodiment of the present invention.
FIG. 6 (a) is a graph showing the relationship between the graphene transferred according to the first embodiment of the present invention and FIG. 6 (b) comparing the Raman mapping of the graphene of Example 1 with the graphene transferred without vacuum heat treatment Image.
FIG. 7 is an image obtained by comparing graphenes transferred through vacuum heat treatment according to Example 1 of the present invention and graphenes transferred without performing heat treatment for vacuum, respectively, in contact with distilled water (DI Water).
8 (a) and 8 (b) are images showing the process of transferring graphene according to the first embodiment of the present invention.
9 is an image of graphenes transferred according to Embodiments 1 to 5 of the present invention.
FIG. 10 is an image of a graphene subjected to ultrasonic sonication according to Example 4 of the present invention and a graphene before ultrasonic pulverization.
11 is a graph comparing the results of Raman spectroscopy of each of the graphenes of Example 4 in which ultrasonic pulverization did not proceed and Example 4 in which ultrasonic degradation was performed.
12 is a graph showing the results of analysis of the electrical characteristics of the FET device manufactured according to the sixth embodiment.
13 is a chart showing a current flow of a photo detector manufactured according to Embodiment 7 of the present invention with time.
14 is an image of graphene transferred according to Example 8 of the present invention and graphene transferred to a hexamethyldisilazane (HMDS) substrate without vacuum heat treatment.

Best Mode for Carrying Out the Invention

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

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. Rather, the intention is not to limit the invention to the particular forms disclosed, but rather, the invention includes all modifications, equivalents and substitutions that are consistent with the spirit of the invention as defined by the claims.

1 is a flow chart showing a transfer method of graphene according to an embodiment of the present invention.

A graphene laminate having a support substrate and graphene bonded thereto is prepared (S10).

The formation process of graphene is as follows. Wherein the catalyst metal is disposed on one side of the graphene of the graphene laminate, and the graphene is formed on the catalyst metal. The graphene may be formed as a single layer or multilayer having a certain thickness on the catalytic metal, but is not limited thereto.

The catalyst metal may be a catalyst metal, which is a single metal substrate made of only a metal, or a catalytic metal combined with another member, which is used for graphene synthesis. The catalytic metal combined with the other member may be, for example, copper (Cu) formed of a metal layer on a silicon wafer (SiO ₂ / Si) substrate having silicon oxide, which is irradiated with an electron beam or a sputter Sputtering) method. The catalytic metal may be in the form of a plate having a predetermined size. The catalytic metal may be at least one selected from the group consisting of copper (Cu), nickel (Ni), cobalt (Co), iron (Fe), platinum (Al), magnesium (Mg), chromium (Cr), and silicon (Si).

The graphene synthesized on the catalyst metal may be deposited by a chemical vapor deposition (CVD) process. The chemical vapor deposition may be performed by, for example, rapid thermal chemical vapor deposition (RTCVD), inductively coupled plasma-chemical vapor deposition (ICP-CVD), or low pressure chemical vapor deposition chemical vapor deposition (LPCVD), atmospheric pressure chemical vapor deposition (APCVD), metal organic chemical vapor deposition (MOCVD), or plasma-enhanced chemical vapor deposition (PECVD) ). A graphene may be formed by supplying a reactive gas including a carbon source onto the catalyst metal by the chemical vapor deposition method. The carbon source may include, for example, carbon monoxide, carbon dioxide, methane, ethane, ethylene, ethanol, acetylene, propane, butane, butadiene, pentane, pentene, benzene or toluene.

The formation of graphene on the catalytic metal can be performed by heat treatment at a temperature of 300 ° C. to 2000 ° C. or by heat treatment at a temperature lower than the melting point of the catalytic metal and can be carried out at a pressure of 10 ^-7 Torr to atmospheric pressure . The graphene formed on the catalyst metal may be subjected to a predetermined cooling process. This is for the purpose of uniformly growing and uniformly arranging the formed graphene. For example, the graphene can be cooled at a rate of 1 deg. C to 50 deg. C per second, or a natural cooling method may be used. The heat treatment and the cooling process may be repeatedly performed to improve the crystallinity of graphene.

The supporting substrate may have at least one spacing space, and the graphene may be disposed in a spacing space of the supporting substrate. The shape of the spacing space may be a circle or a polygon. The support substrate may be a substrate having an acid resistance of pH 3 or less or an alkali resistance of pH 10 or more and a heat resistance at 100 占 폚 to 300 占 폚. That is, the supporting substrate may be made of an acidic or pH-10 basic material having a pH of 3 or less and an acid-resistant or a pH-resistant base material, respectively, so that the supporting substrate may not be damaged by the processes during the catalytic metal etching process and the graphene washing process. May be a substrate having basicity. In addition, the support substrate may be a substrate having heat resistance capable of maintaining the characteristics of the support substrate even at a temperature of 100 ° C to 300 ° C during graphene transfer using the vacuum heat treatment of the present invention.

The supporting substrate may be made of a material such as polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyethylene sulfone (PES), polydimethylsilonane (PDMS), polycarbonate (PC), polyimide But are not limited to, polypropylene terephthalate (PPT), polyetherimide (PEI), or polyarylate (PAR).

And an adhesion member for bonding the support substrate and the graphene. The formation of the adhesion member for bonding between the graphene formed on the catalyst metal and the spacing space between the support substrate may be performed by applying the adhesion member to one surface of the graphene or the support substrate, . The adhesive member may be applied to the support substrate region around the graphene or the spacing space of the support substrate to form an adhesive member between the graphene and the spacing space between the support substrate. The adhesive member may be formed of one kind of material, but may be formed of two or more kinds of materials as necessary. For curing the adhesive member, for example, a convection oven or a UV curing machine may be used, but it is not particularly limited.

The adhesive member may be an adhesive material having an acid resistance of pH 3 or less or an alkali resistance of pH 10 or more and a heat resistance at 100 占 폚 to 300 占 폚. That is, the adhesive member may have an acid resistance or an alkali resistance for acidic or pH 10 or more basic substances which can be contacted during graphene transfer using the vacuum heat treatment of the present invention. In addition, the adhesive member may have heat resistance capable of maintaining the characteristics of the adhesive member even at a temperature of 100 ° C to 300 ° C during the graphene transfer using the vacuum heat treatment of the present invention. The adhesive member may be such that the graphene is supported by the support substrate so that the graphene is not damaged during the process.

The adhesive member may be formed of a material such as polyimide, polymethylmethacrylate (PMMA), polydimethylsiloxane (PDMS), polyvinylidene fluoride (PVDF), or UV But are not limited to, curable polymers.

The step of applying the adhesive member onto the graphene can be carried out by a known method such as spin coating, dip coating, tape casting, screen printing, inkjet printing, nozzle printing, electrophoretic deposition, But are not limited to, For example, the step of applying the adhesive member onto the graphene may use a spin coating method, and the adhesive member may be coated on the graphene by spin coating to a thickness . If the thickness of the adhesive member is too large, the surface of the adhesive member may not be sufficiently flexible, so that the graphene may not be accurately transferred along the surface curvature of the transfer target substrate. In addition, when the thickness of the adhesive member is too small, the adhesive member may be torn due to an adhesive force or gravity to the aqueous solution during the wet process such as the catalyst metal removing process and the graphening cleaning process.

By attaching the cured adhesive member around the spacing space of the supporting substrate, a graphene laminate composed of a supporting substrate / adhesive member / graphene / catalytic metal can be produced. This makes it possible to prevent the graphene from being directly supported on the support substrate by attaching the graphene laminate around the spacing space of the support substrate using a support substrate having a spacing space, The influence can be minimized.

After the step of bonding the support substrate and the graphene to form the graphene laminate, the catalyst metal disposed on the graphene side of the graphene laminate can be removed. The catalyst metal used for the formation of graphene can be removed for the graphene transfer process described below. The step of removing the catalytic metal disposed on the graphene side of the graphene laminate may be performed by an etching process using an etching solution containing CuCl ₂ , KOH, FeCl ₃ , HCl, HF, or a combination of two or more thereof can do. After the catalyst metal is removed, it may be washed with DI water or the like.

The graphene laminate and the transfer target substrate are subjected to vacuum heat treatment to transfer the graphene of the graphene laminate to the transfer target substrate (S20).

The graphene laminate and the substrate to be transferred may be subjected to a heat treatment at a temperature of 150 ° C to 250 ° C in a vacuum atmosphere. When the temperature of the heat treatment is less than 150 캜, sufficient energy for transferring the graphene between the graphene of the graphene laminate and the transfer target substrate is not formed, Can not be achieved. If the temperature of the heat treatment is higher than 250 ° C., the adhesion member formed between the support substrate and the graphene of the graphene laminate may not be removed well or may be defective at a temperature of 250 ° C. or higher. , Resulting in the generation of gas resulting in contamination of the vacuum chamber or graphene and the substrate to be transferred. The adhesion strength between the graphene and the transfer target substrate can be enhanced by the vacuum heat treatment. This is because heat treatment is performed in a vacuum atmosphere to remove molecules existing between the graphene and the transfer target substrate at the time of transfer and improve the bonding force with the transfer target substrate. The vacuum atmosphere may be, for example, 10 ^-7 Torr to 10 ^-2 Torr.

The transfer target substrate can be applied to all the substrates for which graphene transfer is desired. The transfer target substrate may include, for example, polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polycarbonate (PC), silicon wafer, glass, ion exchange film, But is not limited thereto.

After the step of vacuum heat-treating the graphene laminate and the transfer target substrate to transfer the graphene of the graphene laminate to the transfer target substrate, the adhesive residue residue on the graphene surface on the transfer target substrate can be cleaned have. The step of cleaning the adhesive residue on the surface of the graphene on the transfer target substrate may be carried out using an etching solution containing at least one of acetone, isopropyl alcohol, nitric acid etching solution, hydrogen peroxide etching solution and deionized water . The quality of the graphene can be maintained by removing PMMA as an adhesive member by the adhesive solution residue of the graphene, for example, acetone by the etching solution.

The transfer target substrate onto which the graphene is transferred can be applied to various electric devices. For example, an organic light emitting diode (OLED), an inorganic light emitting diode, an inorganic thin film transistor, a field-effect transistor, an inorganic solar cell Solar cells, organic photovoltaic devices (OPV), memories, electrochemical / biosensors, RF devices, photodetectors, optical waveguides, CMOS devices, or lithium batteries or fuel cells As shown in FIG.

For example, in accordance with the present invention, a photodector can be fabricated using graphene transferred on a transfer target substrate as a channel, and further including a source electrode, a drain electrode, and a gate electrode. The photodetector is a device that detects an optical signal and converts the optical signal into an electrical signal. Generally, the photodetector is fabricated on the basis of Si. However, since the energy band gap of Si is small, the lifetime of the device is shortened. By applying the graphene having improved quality transferred according to the present invention to such a photodetector, it is possible to utilize the excellent electrical conductivity characteristics of graphene. Also, since graphene absorbs incident light of about 2.3% of a single layer, it can absorb 0.1% or less (visible light band) of incident light and absorb from the UV band to the THz band, The detector may have the effect of being able to operate in a broader wavelength band.

In addition, for example, a field-effect transistor can be fabricated by applying graphene transferred onto a transfer target substrate according to the present invention. The graphene may be included in the channel layer and the source electrode and the drain electrode may be formed on both sides of the substrate to electrically connect to the channel layer of the graphene. Therefore, it is possible to apply the excellent charge mobility characteristic inherent to graphene, and it is possible to improve the electrical characteristics of the field effect transistor employing the graphene.

According to another aspect of the present invention, there is provided a method of manufacturing a transfer target substrate, which comprises a graphene supply unit for supplying a support substrate having a graphene disposed at one side thereof in a vacuum chamber, And a heat supply unit located below the transfer target substrate supply unit and providing heat to the transfer target substrate.

The vacuum chamber is configured to form a vacuum atmosphere during graphene transfer using the graphene transfer apparatus of the present invention, and may be configured to include a size including the graphene supply unit, the transfer target substrate supply unit, and the heat supply unit. A vacuum atmosphere is created in the process of contacting and transferring the transfer target substrate supply unit and the graphen supply unit through the configuration of the vacuum chamber to thereby act as a dopant in the graphene transfer process, Such as water or oxygen, which can affect the flow of the gas.

The graphene supply part may be constituted of a graphene / adhesive member / support substrate by attaching the graphene to the support substrate by an adhesive member. The graphene supply unit may be configured to provide graphene for graphen transfer, and the graphene may be in contact with the transfer target substrate supply unit. The graphene supply unit may be configured to continuously supply the graphene into the vacuum chamber, or may be configured to supply the graphene unit in units of a predetermined size. And a roller or the like which can advance the pressing so that the contact between the graphen supply unit and the transfer target substrate supply unit can be improved. The apparatus may further include a position control device that can be disposed apart from the transfer target substrate supply part in disposing the graphene supply part before performing the graphene transfer. The position control device may be, for example, a robot arm capable of changing a position of a material object up and down and right and left, but is not limited thereto.

The transfer target substrate supply unit is configured to provide a transfer target substrate for transferring graphene, and the transfer target substrate may be configured to be in contact with the graphen supply unit. And a material capable of withstanding the heat of the heat supply unit when the heat supply unit for supplying heat to the transfer target substrate is disposed at the lower end of the transfer target substrate supply unit. The transfer target substrate supply unit may be configured to continuously supply the substrate to the vacuum chamber, or may be configured to supply the substrate in units of a predetermined size. The transfer target substrate supply unit may further include a separate device capable of controlling a separation distance between the graphen supply unit and the transfer target substrate.

The heat supply unit may be configured to provide heat to the transfer target substrate of the transfer target substrate supply unit, and may include a heater such as a hot plate. The heat supply unit may be disposed at a lower end of the vacuum chamber, and may supply heat to the transfer target substrate or the graft in contact with the transfer target substrate and the transfer target substrate during the graphen transfer process, It is possible to provide an effect that the adhesion force of the transfer target substrate can be increased.

The graphene transfer device of the present invention may further include a position control device disposed on a side surface of the heat supply part and the transfer target substrate supply part, wherein the graphene supply part and the transfer target substrate supply part The distance may be controlled.

2 is a schematic diagram of a graphen transfer apparatus according to an embodiment of the present invention.

Referring to FIG. 2, the graphene transfer apparatus of the present invention may constitute a vacuum chamber 100 and a robot arm 500 as a position control device in the vacuum chamber 100. A graphen supply unit 200 including a support substrate 210 having a graphene 220 disposed in an arm region of the robot arm 500 may be configured. The position of the graphen supply unit 200 can be controlled. A heater 410 as a heat supply unit 400 may be formed on a side surface of the robot arm 500 and a Z axis mover 420 may be additionally formed in a certain region of the heater 410. The Z axis mover 420 can help precisely control the spacing distance of the graphen supply unit 200 whose position is controlled by the robot arm 500. The transfer target substrate 310, which is the transfer target substrate supply unit 300, can be formed on the heater 410.

A vacuum atmosphere for performing graphene transfer may be formed while the graphene supply unit 200 and the transfer target substrate supply unit 300 are disposed in the vacuum chamber 100. Accordingly, it is possible to remove elements that may affect graphene transfer such as water or oxygen on the surface of the graphene 220 and the substrate 310 to be transferred. The position of the graphen supply unit may be controlled via the robot arm 500 so that the transfer target substrate supply unit 300 can be brought into contact with the graphen supply unit 200. The graphene transfer method using the vacuum heat treatment of the present invention can be performed by supplying heat through the heater 410 while the graphen supply unit 200 and the transfer target substrate supply unit 300 are in contact with each other.

The graphene transfer apparatus of the present invention may further include a first roller for pressing one surface of the graphen supply unit to adhere the graphen supply unit and the transfer target substrate supply unit.

3 is a schematic diagram of a graphen transfer apparatus according to another embodiment of the present invention.

Referring to FIG. 3, the graphene transfer apparatus of the present invention may constitute a vacuum chamber 100 and a robot arm 500 as a position control device in the vacuum chamber 100. A graphen supply unit 200 including a support substrate 210 having a graphene 220 disposed in an arm region of the robot arm 500 may be configured. The position of the graphen supply unit 200 can be controlled. A heater 410 as a heat supply unit 400 may be formed on the side surface of the robot arm 500. The transfer target substrate 310, which is the transfer target substrate supply unit 300, can be formed on the heater 410.

The graphen supplying unit 200 may be provided on one side of the graphen supplying unit 200 by pressing the graphen supplying unit 200 in a direction opposite to the direction in which the graphen supplying unit 200 approaches the transfer target substrate supplying unit 300, A first roller 600 for joining the transfer target substrate supply unit 300 can be further configured. The first roller 600 presses the graphen supply unit 200 from one side to the other side to join the graphen supply unit 200 and the transfer target substrate supply unit 300 in a straight line, 200 and the transfer target substrate supply unit 300 can proceed sequentially.

This is because the materials capable of causing micro bubbles or doping that can be generated when the entire area of each of the graphene supplying unit 200 and the transfer target substrate supplying unit 300 are bonded at the same time The graphene transfer method using the vacuum heat treatment method of the present invention can further effectively improve the bonding force between the graphene and the substrate to be transferred during the graphene transfer and secure the inherent characteristics of the graphene .

The graphene transfer apparatus of the present invention may further include a conveyor belt for continuously supplying the graphene supply unit and the transfer target substrate supply unit. And the graphene supply unit and the transfer target substrate supply unit are moved and transferred in one direction within the vacuum chamber by the conveyor belt.

A first roller 610 for pressing one surface of the graphen supply unit and joining the graphen supply unit and the transfer target substrate supply unit and a second roller 620 for pressing one surface of the transfer target substrate supply unit .

4 is a schematic diagram of a graphen transfer apparatus according to another embodiment of the present invention.

4, the graphene transfer apparatus of the present invention includes a graphen supply unit 200 including a vacuum chamber 100 and a support substrate 210 having a graphene 220 disposed therein, Wherein the graphen supply unit 200 is moved to one side in the vacuum chamber 100 on the upper side of the graphen supply unit 200 and the first conveyor A belt 700 may further be constructed. A large area graphene transfer can be performed while the graphene 220 of the graphen supply unit 200 is continuously supplied by the first conveyor belt 700. The transfer target substrate supplying unit 300 including the transfer target substrate 310 may be configured to be spaced apart from the graphen supplying unit 200. The transfer target substrate supply unit 300 is moved to the lower side of the transfer target substrate supply unit 300 in the vacuum chamber 100 to continuously supply the transfer target substrate supply unit 300, A belt 710 and a third conveyor belt 720 may be further configured. The transfer target substrate 310 of the transfer target substrate supply unit 300 is continuously supplied by the second conveyor belt 710 and the third conveyor belt 720 and the large area graphene transfer It can be possible.

The graphen supplying unit 200 presses one surface of the graphen supplying unit 200 in a direction in which the graphen supplying unit 200 approaches the transfer target substrate supplying unit 300 to transfer the graphen supplying unit 200 and the transfer target substrate supplying unit 300 A first roller 610 to be joined may be formed on the graphen supply unit 200. The second roller 620 that presses the transfer target substrate supply unit 300 in the direction in which the graphen supply unit 200 approaches the transfer target substrate supply unit 300 transfers the transfer medium to the transfer target substrate supply unit 300, As shown in FIG. The graphene supply unit 200 and the transfer target substrate supply unit 300 are joined in a straight line by the first roller 610 and the second roller 620, The bonding force of the transfer target substrate 310 can be further improved.

Graphen transfer is performed by applying a low temperature or mechanical pressure to use a thermal release tape in a roll-to-roll type graphen transfer apparatus. In contrast, in the present invention, a graphene transferring apparatus for vacuum heat treatment is constituted so that impurities between the graphene and a transfer target substrate can be originally removed by vacuum atmosphere composition during graphene transfer, The graphene can be transferred to the transfer target substrate by spontaneous bonding between the graphene and the transfer target substrate by supplying heat during the pin transferring process.

5 is a schematic diagram of a graphen transfer apparatus according to another embodiment of the present invention.

5, a graphene transfer apparatus according to the present invention includes a vacuum chamber 100, a graphene 220 disposed on a transfer target substrate supply unit 300 including a transfer target substrate 310 in the vacuum chamber 100, The graphen supplying unit 200 includes the supporting substrate 210 on which the graphen supplying unit 200 and the transferring substrate supplying unit 300 are mounted by the first roller 600, have. Further, a heat supply unit including a heater 410 for supplying heat to the transfer target substrate 310 is disposed under the transfer target substrate supply unit 300. A stage moving device 440 is disposed under the heater 410 so that the stage moving device 440 can move the transfer target substrate supply part 300 in the X, Y, and Z directions. It is possible to optimize the transfer process of the large area graphene by adjusting the distance and position between the transfer target substrate and the graphen supply unit through the up-down movement of the first roller 600 and the three-dimensional movement of the stage moving unit 440 .

Thus, the transfer of graphene according to the graphene transfer apparatus of the present invention can have an effect of increasing the adhesive force between the graphene and the substrate to be transferred, and can have the advantage of securing the inherent characteristics of the graphene . This is because, in the conventional roll-to-roll type graphene transfer apparatus, the adhesion force between the graphene and the substrate to be transferred is insufficient due to the low temperature, and the graphene is damaged by impurities during the graphene transfer process proceeding at normal pressure This may mean that the graphene transfer state is improved by minimizing the possible factors.

DETAILED DESCRIPTION OF THE INVENTION

[Example]

≪ Example 1 >

PMMA as an adhesive layer was coated on top of the graphene synthesized on a copper foil as a catalytic metal by a spin coating method. The adhesive layer of PMMA was cured in an oven or the like and then adhered to a PEN substrate having a spacing space (frame). The graphene laminate composed of the PEN substrate / PMMA / graphene / catalyst metal was heat-treated at a temperature of 120 ° C for 20 minutes. Thereafter, copper was removed by contacting with an etchant mixed with FeCl ₃ , HCl and DI water (distilled water) at a temperature of 50 ° C for 5 minutes to remove copper as a catalytic metal of the graphene laminate , Immersed in HCl solution for 20 minutes to clean the remaining graphene residue, and then immersed in DI water solution for another 1 hour. The graphene layer was transferred to a hydrophilic SiO ₂ substrate prepared as a transfer target substrate by vacuum heat treatment at a temperature of 200 ° C in a vacuum atmosphere of 10 ^-2 torr by contacting the graphene laminate having the catalyst metal removed thereon. Thereafter, the PEN substrate was removed and the PMMA was removed with acetone to obtain graphene transferred onto the transfer target substrate.

 For comparison, graphene was transferred onto a transfer target substrate without vacuum heat treatment to make a comparative example.

6 (a) is an image showing the Raman spectrum of the graphene transferred according to Example 1 of the present invention, and FIG. 6 (b) is a graph showing the Raman spectrum of the graphene transferred without vacuum heat treatment Raman mapping.

Referring to FIG. 6 (a), it can be confirmed that the surface of the graphene transferred according to Example 1 of the present invention was cleanly transferred without wrinkles or cracks. The Raman spectrum of each region divided by point ¹ to point 5 of the graphene shows a D peak at around 1350 cm ^-1 and a G peak at about 1580 cm ^-1 , ^-1 >, it can be confirmed that a 2D peak is observed in the vicinity of ^-1 . This is similar to that found in the Raman spectra of general graphene, and according to Example 1 of the present invention, the graphene grains which had undergone thermal transfer under a low vacuum atmosphere maintained the inherent crystallinity of graphene, Can be understood to have proceeded well.

The degree of defects of the graphene can be known through the intensity ratio ( _{D / G} ) between the D peak and the G peak. The lower the value, the better the quality of the graphene. In FIG. 6 (a), the intensity of the D peak is very weak, and it can be seen that the graphene transferred by the vacuum heat treatment according to Example 1 of the present invention has few defects in the graphene crystal and good quality. It can be seen that the transfer of graphene is improved by removing the impurities that may affect the graphene surface by preventing the contact with moisture or oxygen due to the vacuum composition while performing the heat treatment under vacuum atmosphere in the transfer process of graphene have.

Referring to FIG. 6 (b), the left image shows the Raman mapping result of the graphene transferred without vacuum heat treatment, and the position of the G peak was changed from 1590 cm ^-1 to 1602 cm ^-1 . This is because dopants such as water may remain while being subjected to a wet process based on distilled water for etching of the catalyst metal during the transfer process of the graphene and graphene is doped, May be replaced with a new one. The image on the right is the Raman mapping result of graphene of Example 1 of the present invention and maintains the G peak region of 1580 cm ^-1 to 1590 cm ^-1 of a general graphene grains. By transferring graphene through a vacuum heat treatment, It can be seen that the characteristics of the pin are maintained.

FIG. 7 is an image obtained by comparing graphenes transferred through vacuum heat treatment according to Example 1 of the present invention and graphenes transferred without performing a heat treatment for vacuum in contact with distilled water (DI Water).

Referring to FIG. 7, the right region of the image is contacted with distilled water (DI Water) by the transferred graphene without performing the vacuum heat treatment, and it can be confirmed that the transferred graphene is almost separated. Thus, it can be seen that the graphene transferred without vacuum heat treatment is not easily adhered to the substrate and can be easily damaged. In contrast, in the left region of the image, graphene transferred through vacuum heat treatment according to Example 1 of the present invention can be confirmed that there is no change in the state of graphene transferred even after contact with distilled water (DI Water). As a result, it can be seen that the graphenes transferred through the vacuum heat treatment of the present invention have high adhesive force with the substrate, so that the characteristics and quality of the graphenes can be maintained as they are. It may be advantageous to fabricate a device using the same.

≪ Example 2 >

The experiment was carried out in the same manner as in Example 1 except that the heat treatment was performed at a temperature of 175 캜 in the vacuum heat treatment, to obtain transferred graphene.

≪ Example 3 >

The experiment was carried out in the same manner as in Example 1 except that the heat treatment was performed at a temperature of 190 캜 in the vacuum heat treatment, to obtain transferred graphene.

<Example 4>

The experiment was carried out in the same manner as in Example 1 except that the heat treatment was performed at a temperature of 195 캜 in the vacuum heat treatment, to obtain transferred graphene.

8 (a) and 8 (b) are images showing the process of transferring graphene according to the first embodiment of the present invention.

When Fig. 8 (a) and FIG. 8 (b), Figure 8 (a) is in accordance with the first embodiment of the present invention ¹⁰ in the process is in a graphene transferred under 2torr vacuum atmosphere, transfer is carried out in the vacuum heat treatment Is an image showing an area of attachment of graphene on a substrate to be transferred at a temperature of 175 ° C. It can be confirmed that the contact area of the graphene is formed only on a part of the transfer target substrate. 8 (b) shows that the attached area of the graphene on the substrate to be transferred is further enlarged in the course of raising the temperature to 200 ° C according to Example 1 under a 10 ^-2 torr vacuum atmosphere. This is because, by carrying out graphene transfer using a vacuum heat treatment, spontaneous bonding between the graphene and the transfer target substrate is induced between the graphene and the transfer target substrate by the heat treatment, and adhesion between the graphene and the transfer target substrate And the transfer state of the graphene is improved. Further, impurities that can cause doping in water or graphene such as water and oxygen existing between the graphene and the transfer target substrate immediately before the graphene is transferred to the transfer target substrate by the vacuum atmosphere can be originally removed Therefore, it is possible to minimize the factors influencing the quality of the graphene during graphene transfer.

9 is an image of graphenes transferred according to Embodiments 1 to 5 of the present invention.

Referring to FIG. 9, it can be seen that as the heat treatment temperature of the vacuum heat treatment at the time of transfer increases, the graphene is uniformly transferred onto the substrate without any foreign object between the graphene and the transfer target substrate. This is because the spontaneous coupling between the graphene and the substrate to be transferred is induced by the vacuum heat treatment at the time of graphene transfer as described above, and the bonding force of graphene to the transfer target substrate is increased.

&Lt; Example 5 >

The graphene transferred according to Example 1 was contacted with acetone and subjected to ultrasonic sonication for 1 minute. The ultrasonic pulverization is performed by using a sonic wave of 10 kHz to 20 kHz to rinse, destroy cells or intracellular structures, and the ultrasonic pulverizer can be used.

FIG. 10 is an image of a graphene subjected to ultrasonic sonication according to Example 4 of the present invention and a graphene before ultrasonic pulverization.

Referring to FIG. 10, it can be seen that the surface of the transferred graphene was cleaned while the acetone was dispersed while the ultrasonic pulverization was performed with acetone. This may mean that the quality of the graphene is improved by removing the residue of the PMMA which is an adhesive member remaining in the graphene by the dispersed acetone. Further, it can be seen that the adhesive force between the graphene and the substrate to be transferred is enhanced by the vacuum heat treatment of the present invention through the fact that only the residue of the adhesive member is removed during the ultrasonic pulverization and there is no change in the crystal graphene.

That is, in the case of the graphene transfer method using the conventional wet process, the adhesion between the graphene and the substrate to be transferred is not good and the process using the ultrasonic wave can not be applied. In the present invention, But also an ultrasonic process capable of improving the quality of the graphene can be performed, so that the effect of maintaining the characteristics of the graphene in the graphene transfer process can be obtained.

11 is a graph comparing the results of Raman spectroscopy of each of the graphenes of Example 4 in which ultrasonic pulverization was not performed and Example 4 in which ultrasonic degradation was performed.

Referring to FIG. 11, it can be seen that there is no large change in the image of graphene at point 1 to point 2 before and after the ultrasonic pulverization, and the Raman spectrum according to the ultrasonic pulverization of Example 4 does not change much. As described above with reference to FIG. 4, since the graphene grains are maintained in good crystallinity even after ultrasonic pulverization, it can be seen that the bonding force between the graphene and the substrate to be transferred is high.

&Lt; Example 6 >

The graphene transferred according to Example 1 was applied as a channel layer, and a field effect transistor (FET) electrically connected to the source electrode and the drain electrode was fabricated. As a comparative example in Example 1, an FET employing graphene transferred without vacuum heat treatment was also produced.

12 is a graph showing the results of analysis of the electrical characteristics of the FET device manufactured according to the sixth embodiment.

Referring to FIG. 12, in the case of an FET device using graphene transferred using the vacuum heat treatment according to the present invention, the Dirac point is measured in the vicinity of almost 0 V, and it is confirmed that the data is symmetrical with respect to the Dirac point have. In contrast, in the case of the FET device using the graphene transferred without the vacuum heat treatment manufactured in the comparative example, the data of the Dirac point is changed due to the hole doping. That is, during the transfer process of the graphene transferred without vacuum heat treatment, the transfer condition is changed by the dophant such as water or oxygen between the graphene and the transfer target substrate, And thus it affects the electrical characteristics of the FET device to which it is applied.

&Lt; Example 7 >

A photodetector including the drain electrode, the source electrode, and the gate electrode was fabricated by incorporating the graphene transferred according to Example 1 as a channel layer. As a comparative example in Example 1, a photodetector using graphene transferred without vacuum heat treatment was also prepared.

13 is a chart showing a current flow of a photo detector manufactured according to Embodiment 7 of the present invention with time.

13, in the case of the photodetector using the graphene transferred by vacuum heat treatment according to the first embodiment of the present invention, the comparative graphene transferred without vacuum heat treatment to 1395.9 nA under the same electric field condition The photocurrent of the photodetector was measured to be 4 times higher than that of 385.9 nA. It can be assumed that the electron mobility of graphene is reduced by hole doping during transfer of the graphene transferred without vacuum heat treatment as described above with reference to FIG. 9, It is also seen that it is decreased. As a result, in the case of the graphene transferred using the vacuum heat treatment of the present invention, the influence of doping is removed by vacuum to secure intrinsic characteristics of the graphene, It can be seen that it is improved.

&Lt; Example 8 >

The transferred graphene was obtained in the same manner as in Example 1, except that a substrate to be transferred was a hexamethyldisilazane (HMDS) substrate, which is a hydrophobic substrate. For comparison, graphene transferred to the same HMDS substrate as the transfer target substrate without using a vacuum heat treatment was prepared.

14 is an image of graphene transferred according to Example 8 of the present invention and graphene transferred to HMDS substrate without vacuum heat treatment.

Referring to FIG. 14, the left image is graphene transferred onto the HMDS substrate without vacuum heat treatment, and it can be confirmed that the graphene is torn or wrinkled. This is because graphene is not uniformly adhered to the substrate due to the DI water (distilled water) present between the substrate and the graphene during the transferring process due to the characteristics of the hydrophobic substrate, and the graphene is damaged by the drying process .

On the other hand, the right image shows that the graphene transferred onto the HMDS substrate, which is a hydrophobic substrate, by vacuum heat treatment, is transferred graphene without wrinkles or cracks. As a result, since the adhesion of the hydrophobic substrate of the present invention is proceeded by spontaneous bonding of the graphene and the substrate by the vacuum heat treatment, graphene is uniformly transferred without being influenced by the substrate characteristics of the substrate.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

Claims (14)

Preparing a graphene laminate having a support substrate and graphene bonded thereto; And
And transferring the graphene of the graphene laminate to the transfer target substrate by vacuum heat-treating the graphene laminate and the transfer target substrate. The method according to claim 1,
Wherein the supporting substrate has at least one spacing space and the graphenes are disposed in a spaced apart space of the supporting substrate. 4. The method according to any one of claims 1 to 3,
Wherein the support substrate has an acid resistance of pH 3 or less or a basicity of pH 10 or higher; And
Wherein the substrate is a substrate having heat resistance at 100 占 폚 to 300 占 폚. The method according to claim 1,
And a bonding member for bonding the supporting substrate and the graphene to each other. 5. The method of claim 4,
Applying the adhesive member to one surface of the graphene or one surface of the support substrate, and then curing the applied adhesive member to adhere the graphene to the support substrate. 6. The method of claim 5,
Wherein the adhesive member has an acid resistance of pH 3 or less or an inorganic basicity of pH 10 or higher; And
Wherein the adhesive member is a bonding member having heat resistance at 100 占 폚 to 300 占 폚. The method according to claim 1,
And transferring the graphene of the graphene laminate to the transfer target substrate by vacuum heat-treating the graphene laminate and the transfer target substrate,
Wherein the graphene laminate and the transfer target substrate are subjected to heat treatment at a temperature of 150 to 250 캜 under a vacuum of 10 ^-7 torr to 10 ^-2 torr. Within the vacuum chamber,
A graphene supply unit for supplying graphene disposed on one side of the support substrate;
A transfer target substrate supply unit disposed apart from the graphen supply unit and providing a transfer target substrate onto which the graphene is to be transferred; And
And a heat supply unit positioned below the transfer target substrate supply unit and providing heat to the transfer target substrate. 9. The method of claim 8,
Wherein the graphen supply unit comprises:
Wherein the graphen is attached to the support substrate by an adhesive member and is made of a graphene / adhesive member / support substrate. 9. The method of claim 8,
The graphene transfer apparatus includes:
Further comprising a position control device disposed on a side surface of the heat supply part and the transfer target substrate supply part,
Wherein a distance between the graphen supply unit and the transfer target substrate supply unit is adjusted by the position control device. 9. The method of claim 8,
The graphene transfer apparatus includes:
Further comprising a stage moving device disposed below the heat supply,
And the three-dimensional movement of the transfer target substrate supply unit is performed by the stage moving apparatus. 11. The method of claim 10,
The graphene transfer apparatus includes:
Further comprising a first roller for pressing one surface of the graphen supply unit to bond the graphen supply unit to the transfer target substrate supply unit. 9. The method of claim 8,
The graphene transfer apparatus includes:
And a conveyor belt for continuously supplying the graphen supply unit and the transfer target substrate supply unit. 14. The method of claim 13,
The graphene transfer apparatus includes:
Further comprising a first roller for pressing one surface of the graphen supply unit to join the graphen supply unit and the transfer target substrate supply unit and a second roller for pressing one surface of the transfer target substrate supply unit, Device.

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