WO2015102459A1

WO2015102459A1 - Graphene transfer method and graphene transfer apparatus using vacuum heat treatment

Info

Publication number: WO2015102459A1
Application number: PCT/KR2015/000085
Authority: WO
Inventors: 이병훈; 이상경; 이상철
Original assignee: 광주과학기술원
Priority date: 2014-01-06
Filing date: 2015-01-06
Publication date: 2015-07-09
Also published as: KR20160089529A; KR101899224B1

Abstract

Provided are a graphene transfer method and a graphene transfer apparatus. Specifically, the present invention provides a graphene transfer method and a graphene transfer apparatus that can carry out the same, the method comprising the steps of: manufacturing a graphene stack having a support substrate and graphene coupled to each other; and vacuum heat-treating the graphene stack and a transfer-target substrate so as to transfer the graphene of the graphene stack to the transfer-target substrate. Accordingly, the graphene transfer process is performed under the vacuum atmosphere so that elements causing doping between the graphene and the transfer-target substrate are removed, thereby transferring the graphene while maintaining the characteristic of the graphene. In addition, a bonding force between the graphene and the transfer-target substrate is increased by heat treatment when the graphene is transferred, thereby enhancing the graphene transfer state.

Description

Graphene Transfer Method and Graphene Transfer Device Using Vacuum Heat Treatment

The present invention relates to a graphene transfer method and a graphene transfer device, and more particularly, to a graphene transfer method and a graphene transfer device therefor by vacuum heat treatment.

Graphene (Graphene) refers to a layer of atoms in which the carbon atoms have a honeycomb arrangement in two dimensions. The thickness is 0.2 nm, and the physical and chemical stability is high. Specifically, the graphene has a high charge transfer, excellent transmittance, excellent flexibility and strength, which is a very promising material for next-generation electronic devices and optoelectronic devices. In addition, the good bending characteristics 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.

In general, the graphene may be manufactured by chemical vapor deposition (CVD) on a metal layer. This is because the graphene produced by the chemical vapor deposition method is the most excellent and can be mass-produced. However, when manufacturing graphene by chemical vapor deposition, first, since the synthesis on the silicon wafer substrate or metal substrate on which the metal catalyst layer is formed, to transfer the graphene synthesized on the metal layer to a desired substrate to apply the graphene to the device There is a need for a transfer process.

In general, the transfer process of graphene, the graphene formed on the metal layer is an adhesive support layer such as thermal release tape (Thermal Releasing Tape), polydimethylsiloxane (PDMS), or polymethyl methacrylate (PMMA) There is known a method of transferring to a desired substrate by using.

However, through the transfer method, foreign matter is present between the graphene and the substrate due to moisture or oxygen in the air during the wet etching process during the transfer of the graphene or oxygen during the transfer of the graphene. There are disadvantages. In addition, there is a problem in that the quality of the graphene is easily damaged when manufacturing the device to which the graphene and the transferred graphene is applied due to weak adhesion between the substrate and the substrate.

The problem to be solved by the present invention is to minimize the factors that affect the degradation of the graphene when performing the transfer process of graphene.

In addition, it is to improve the transfer state of the graphene by improving the adhesion between the graphene and the substrate.

One aspect of the present invention to achieve the above object, the step of preparing a graphene laminate bonded to the support substrate and graphene, and the graphene laminate of the graphene laminate by vacuum heat treatment the substrate and the transfer target substrate It provides a graphene transfer method comprising the step of transferring the pin to the transfer target substrate.

Another aspect of the present invention, in the vacuum chamber, a graphene supply unit for providing a support substrate on which graphene is disposed on one side, a transfer object which is positioned apart from the graphene supply unit and provides a transfer target substrate to which the graphene is transferred It provides a graphene transfer device comprising a substrate supply unit, and a heat supply unit which is located below the transfer target substrate supply unit to provide heat to the transfer target substrate.

According to the present invention, by performing the transfer process of graphene in a vacuum atmosphere it is possible to remove the elements causing the doping (graphing) between the graphene and the substrate to be transferred to ensure the unique characteristics of the graphene.

In addition, by transferring the graphene through heat treatment it is possible to increase the bonding force between the graphene and the substrate to be transferred to improve the graphene transfer state.

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

Figure 2 is a schematic diagram of a graphene transfer device according to an embodiment of the present invention.

Figure 3 is a schematic diagram of a graphene transfer device according to another embodiment of the present invention.

Figure 4 is a schematic diagram of a graphene transfer device according to another embodiment of the present invention.

Figure 5 is a schematic diagram of a graphene transfer device according to another embodiment of the present invention.

Figure 6 (a) is a graphene transferred in accordance with Example 1 of the present invention, Figure 6 (b) is a comparison of Raman mapping for the graphene transferred to the graphene of Example 1 without vacuum heat treatment (Raman mapping) Image.

FIG. 7 is an image comparing graphene transferred through vacuum heat treatment and graphene transferred to DI water without performing vacuum heat treatment according to Example 1 of the present invention.

8 (a) and 8 (b) are images showing a process of transferring graphene according to Example 1 of the present invention.

9 is an image of the graphene transferred in accordance with Example 1 to Example 5 of the present invention.

10 is an image comparing graphene subjected to ultrasonic grinding according to Example 4 of the present invention and graphene before ultrasonic grinding.

FIG. 11 is a graph comparing the results of Raman spectroscopy of each graphene of Example 4 not subjected to ultrasonic grinding and Example 4 subjected to ultrasonic decomposition.

12 is a chart showing the results of analyzing the electrical characteristics of the FET device manufactured according to Example 6.

FIG. 13 is a diagram illustrating a flow of current with respect to time of a photo detector manufactured according to Embodiment 7 of the present invention.

FIG. 14 is an image comparing graphene transferred according to Example 8 of the present invention with graphene transferred to a hexamethyldisilazane (HMDS) substrate without vacuum heat treatment.

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

While the invention allows for various modifications and variations, specific embodiments thereof are illustrated by way of example in the drawings and will be described in detail below. However, it is not intended to be exhaustive or to limit the invention to the precise forms disclosed, but rather the invention includes all modifications, equivalents, and alternatives consistent with the spirit of the invention as defined by the claims.

A graphene laminate in which a support substrate and graphene are combined is prepared (S10).

Formation process of the graphene is as follows. The graphene laminate may include a catalyst metal disposed on one surface of graphene, and the graphene may be formed on the catalyst metal. The graphene may be formed in a single layer or multiple layers having a predetermined thickness on the catalyst metal, but is not particularly limited thereto.

The catalyst metal is used for graphene synthesis, and may be a catalyst metal that is a single metal substrate made of only metal, or a catalyst metal combined with another member. The catalytic metal combined with the other member may be, for example, copper (Cu) formed as a metal layer on a silicon wafer (SiO ₂ / Si) substrate having silicon oxide, which may be an electron beam or sputter ( It can be configured by forming a metal layer in a sputter) method. The catalyst metal may be composed of a plate having a predetermined size, the catalyst metal is copper (Cu), nickel (Ni), cobalt (Co), iron (Fe), platinum (Pt), gold (Au), aluminum At least one selected from (Al), magnesium (Mg), chromium (Cr), and silicon (Si) may be included.

Graphene synthesized on the catalytic metal may be deposited by a chemical vapor deposition (CVD) process. The chemical vapor deposition method is, for example, rapid thermal chemical vapor deposition (RTCVD), inductively coupled plasma-chemical vapor deposition (ICP-CVD), low pressure chemical vapor deposition (low) pressur chemical vapor deposition (LPCVD), atmospheric pressure chemical vapor deposition (APCVD), metal organic chemical vapor deposition (MOCVD) or plasma-enhanced chemical vapor deposition (PECVD) ) May be included. Graphene may be formed by supplying a reaction gas including a carbon source on 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.

Forming graphene on the catalyst metal may be performed by heat treatment at a temperature of 300 ° C. to 2000 ° C., or heat treatment at a temperature lower than the melting point of the catalyst metal, and may be performed at 10 ⁻⁷ Torr to atmospheric pressure. . Graphene formed on the catalytic metal by the above process may be subjected to a predetermined cooling process. This is to allow the formed graphene to grow uniformly and be uniformly arranged. For example, the graphene may be cooled at a rate of 1 ° C. to 50 ° C. per second, and a natural cooling method may be used. The crystallization of graphene may be improved by repeatedly performing the heat treatment and the cooling process.

The support substrate may have one or more separation spaces, and the graphene may be disposed in the separation space of the support substrate. The form of the separation space may be composed of a circle or a polygon. The support substrate may be a substrate having an acid resistance of pH 3 or less or a basic resistance of pH 10 or more and heat resistance at 100 ° C to 300 ° C. That is, the support substrate may be acid resistant or acid resistant to an acidic material having a pH of 3 or less or a basic material having a pH of 10 or more, so that the support substrate may not be damaged by the processes during the etching process of the catalytic metal and the graphene cleaning process. It may be a substrate having basicity. In addition, the support substrate may be a substrate having heat resistance that can maintain the characteristics of the support substrate even at a temperature of 100 ℃ to 300 ℃ when performing graphene transfer using the vacuum heat treatment of the present invention.

The support substrate may be, for example, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyethylene sulfone (PES), polydimethylsiloncene (PDMS), polycarbonate (PC), polyimide (PI), It may include, but is not limited to, polypropylene terephthalate (PPT), polyetherimide (PEI), or polyarylate (PAR).

It may include an adhesive member for coupling the support substrate and the graphene. Forming an adhesive member for bonding between the graphene formed on the catalyst metal and the separation space of the support substrate, after applying the adhesive member on one surface of the graphene or one surface of the support substrate, the adhesive member is cured Can be done. The adhesive member may be applied to an upper portion of the graphene or a support substrate region around the space of the support substrate to form an adhesive member between the graphene and the space of the support substrate. The adhesive member may be formed of one material, but may be formed of two or more materials, if necessary. Curing the adhesive member may be, for example, a convection oven or a UV curing machine, but is not particularly limited.

The adhesive member may be an adhesive member having acid resistance of pH 3 or less or basic resistance of pH 10 or higher and heat resistance at 100 ° C to 300 ° C. That is, the adhesive member may have acid resistance or basic resistance, respectively, to an acidic material having a pH of 3 or less or a basic material having a pH of 10 or more, which may be contacted during graphene transfer using the vacuum heat treatment of the present invention. In addition, the adhesive member may have a heat resistance that can maintain the properties of the adhesive member even at a temperature of 100 ℃ to 300 ℃ when performing graphene transfer using the vacuum heat treatment of the present invention. The adhesive member may be formed so that the graphene may be supported by the support substrate so that the graphene is not damaged during the process.

The adhesive member may be, for example, polyimide, polymethylmethacrylate (PMMA), polydimethylsiloxane (PDMS), polyvinylidene fluoride (PVDF), or UV It may include a curable polymer, but is not limited thereto.

The step of applying the adhesive member on the graphene, for example, spin coating method, dip coating method, tape casting method, screen printing method, inkjet printing method, nozzle printing method, electrophoretic deposition method, or doctor blade coating Act may include, but is not limited to. For example, the process of applying the adhesive member on the graphene may use a spin coating method, and by using a spin coating method on the graphene to adjust the rotational speed and the application time while appropriately thicknessing the adhesive member. Can be applied. When the thickness of the adhesive member is too thick, the surface of the adhesive member may not be sufficiently flexible, so that the graphene may be difficult to be accurately transferred along the surface curvature of the substrate to be transferred. In addition, when the thickness of the adhesive member is too thin, it may be torn by being subjected to the adhesive force or gravity with the aqueous solution during the wet process, such as catalyst metal removal process and graphene cleaning process.

When the cured adhesive member is attached to the space around the space of the support substrate, a graphene laminate including a support substrate / adhesive member / graphene / catalyst metal may be manufactured. It is possible to prevent the graphene from being directly supported by the support substrate by attaching the graphene stack around the separation space of the support substrate by using a support substrate having a separation space, thereby reducing the surface curvature of the support substrate. The impact can be minimized.

After preparing the graphene laminate by adhering the support substrate to the graphene, the catalyst metal disposed on one surface of graphene of the graphene laminate may be removed. The catalyst metal is used for the formation of graphene, and may be removed for the transfer process of graphene described later. Removing the catalyst metal disposed on the graphene surface of the graphene laminate is 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 removing the catalyst metal may be washed using distilled water (DI water) and the like.

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

The graphene laminate and the transfer target substrate may be performed by applying heat treatment at a temperature of 150 ° C. to 250 ° C. under a vacuum atmosphere. When the temperature of the heat treatment is less than 150 ° C, sufficient energy for transferring the graphene is not formed between the graphene of the graphene laminate and the transfer target substrate, so that the graphene is well transferred to the transfer target substrate. It may not be done. In addition, when the temperature of the heat treatment is more than 250 ℃ may be a defect that the adhesive member formed between the support substrate and the graphene of the graphene laminate is not removed well or the support substrate is melted at a temperature of more than 250 ℃ As a result, gas generation may cause contamination of the vacuum chamber or the graphene and the substrate to be transferred. The adhesion between the graphene and the transfer target substrate may be enhanced by the vacuum heat treatment. This may be to remove the molecules that existed between the graphene and the transfer target substrate during heat transfer in a vacuum atmosphere, thereby improving the bonding force with the transfer target substrate. The vacuum atmosphere may be, for example, 10 ⁻⁷ Torr to 10 ⁻² Torr.

The substrate to be transferred may be applied to any substrate for which graphene is to be transferred. The transfer object substrate may include, for example, polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polycarbonate (PC), silicon wafer, glass, ion exchange film, or membrane. It may be, but is not limited thereto.

After vacuum transferring the graphene stack and the transfer target substrate to transfer the graphene of the graphene stack to the transfer target substrate, the adhesive member residue on the surface of the graphene on the transfer target substrate may be cleaned. have. The cleaning of the adhesive member residue on the surface of the graphene on the transfer target substrate may be performed using an etching solution including at least one of acetone, isopropyl alcohol, nitrate etching solution, hydrogen peroxide etching solution, and deionized water. . The quality of the graphene may be maintained while the residue of the adhesive member of the graphene, for example, PMMA, is removed by acetone by the etching solution.

The transfer target substrate to which the graphene is transferred may be applied to various electrical devices. For example, organic light emitting diodes (OLEDs), inorganic light emitting diodes (Inorganic Light Emitting Diodes), inorganic thin film transistors (Inorganic Thin Film Transistors), field-effect transistors, inorganic solar cells (Inorganic) Solar Cells, Organic Photovoltaic Diodes (OPVs), Memory, Electrochemical / Bio Sensors, RF Devices, Photodetectors, Optical Waveguides, CMOS Devices, Lithium Batteries or Fuel Cells It can be used as an electrode.

For example, according to the present invention, a graphene transferred onto a substrate to be transferred may be used as a channel, and a photo detector may be further manufactured by further including a source electrode, a drain electrode, and a gate electrode. The photo detector is a device that detects an optical signal and converts it into an electrical signal. Generally, the photo detector is manufactured based on Si, but has a limitation in that the life of the device is shortened due to the small energy band gap of Si. By applying graphene having improved quality transferred according to the present invention to such a photo detector, it is possible to take advantage of the excellent electrical conductivity of graphene. In addition, graphene is based on graphene-based light because one layer absorbs about 2.3% of incident light, reflects less than 0.1% of the incident light (visible light band), and absorbs from the UV band to the THz band. The detector can have the effect of operating in a wider wavelength band.

Further, for example, according to the present invention, a field-effect transistor to which graphene is transferred on a transfer target substrate may be manufactured. The graphene may be included in the channel layer, and source and drain electrodes may be formed on both substrates, and the graphene may be electrically connected to the channel layer of the graphene. Therefore, it is possible to apply the excellent charge mobility characteristics inherent to the graphene to improve the electrical characteristics of the field effect transistor employing it.

Another aspect of the present invention, in the vacuum chamber, a graphene supply unit for providing a support substrate on which graphene is disposed on one side, a transfer object which is positioned apart from the graphene supply unit and provides a transfer target substrate to which the graphene is to be transferred It provides a graphene transfer device comprising a substrate supply unit, and a heat supply unit which is located below the transfer target substrate supply unit to provide 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 have a size that may include the graphene supply unit, a transfer target substrate supply unit, and a heat supply unit. Through the configuration of the vacuum chamber, the transfer target substrate supply portion and the graphene supply portion by creating a vacuum atmosphere in the process of the contact and the transfer is performed, acting as a dopant (dopant) during the graphene transfer process, the quality of the graphene Other gaseous components such as water and oxygen can be removed at the source.

The graphene supply unit, the graphene is attached to the support substrate by an adhesive member may be composed of a graphene / adhesive member / support substrate. The graphene supply unit is configured to provide graphene for graphene transfer, and may be configured in a form in which the graphene is in good contact with the transfer target substrate supply unit. The graphene supply unit may be configured to continuously supply the vacuum chamber, and may be configured to supply a predetermined size unit. The graphene supply unit may further include a pressurizer, a roller, and the like, which may perform pressurization so that contact between the graphene supply unit and the transfer target substrate supply unit may be improved. When arranging the graphene supply unit before performing the graphene transfer, the position control device may be further spaced apart from the transfer target substrate supply unit. The position control device may be, for example, a robot arm that can change the position of the object up and down, left and right, but is not limited thereto.

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

The heat supply unit is configured to provide heat to the transfer target substrate of the transfer target substrate supply unit, and may include, for example, a heater such as a hotplate. The heat supply unit may be disposed at a lower end of the vacuum chamber, and supplies heat to the graphene in contact with the transfer target substrate or the transfer target substrate and the transfer target substrate during a graphene transfer process. The adhesive force of the transfer target substrate may be increased.

The graphene transfer device of the present invention may further include a position control device disposed on the side of the heat supply unit and the transfer target substrate supply unit, the graphene supply unit and the transfer target substrate supply unit by the position control device The separation distance may be adjusted.

Referring to FIG. 2, the graphene transfer device of the present invention may configure a vacuum chamber 100 and a robot arm 500 that is a position control device in the vacuum chamber 100. A graphene supply unit 200 including a support substrate 210 on which graphene 220 is disposed in an arm region of the robot arm 500 may be configured. The position of the graphene supply unit 200 may be controlled. A heater 410 that is a heat supply unit 400 may be configured on the side of the robot arm 500, and a Z axis mover 420 may be additionally configured in a predetermined region of the heater 410. The Z axis mover 420 may help to control the separation distance of the graphene 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, may be configured on the heater 410.

As the graphene supply unit 200 and the transfer target substrate supply unit 300 are disposed in the vacuum chamber 100, a vacuum atmosphere for performing graphene transfer may be formed. Accordingly, elements that may affect the transfer of graphene, such as water or oxygen, on the surface of the graphene 220 and the transfer target substrate 310 may be removed. The transfer target substrate supply unit 300 may contact the graphene supply unit 200 by controlling the position of the graphene supply unit through the robot arm 500. The graphene transfer method using the vacuum heat treatment of the present invention may be performed by supplying heat through the heater 410 while the graphene 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 pressurizing one surface of the graphene supply unit to bond the graphene supply unit and the transfer target substrate supply unit.

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

The graphene supply unit 200 is pressed on one surface of the graphene supply unit 200 by pressing the graphene supply unit 200 in an opposite direction to approach the transfer target substrate supply unit 300. The first roller 600 may be further configured to bond the transfer target substrate supply part 300 to each other. The graphene supply part by pressing the graphene supply part 200 in one direction from the one side to the other side of the first roller 600 to bond the graphene supply part 200 and the transfer target substrate supply part 300 in a straight line. 200 may be sequentially contacted with the transfer target substrate supply unit 300.

This may further include materials that may cause micro bubbles or doping that may occur when the entire area of each of the graphene supply unit 200 and the transfer target substrate supply unit 300 is simultaneously bonded. By effectively removing, in addition to the effect of the graphene transfer method using the vacuum heat treatment of the present invention, further improves the bonding force between the graphene and the substrate to be transferred when performing the graphene transfer, to ensure the unique characteristics of the graphene Can be.

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. The graphene supply unit and the transfer target substrate supply unit may be transferred and moved in one direction in the vacuum chamber by the conveyor belt.

It further comprises a first roller 610 for pressing the one surface of the graphene supply unit to bond the graphene 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. Can be.

Referring to FIG. 4, the graphene transfer device of the present invention includes a vacuum chamber 100 and a graphene supply unit 200 including a support substrate 210 on which graphene 220 is disposed in the vacuum chamber 100. Is configured, the graphene supply unit 200, the graphene supply unit 200 is moved in one direction in the vacuum chamber 100, the first conveyor capable of continuously supplying the graphene supply unit 200 Belt 700 may be further configured. As the graphene 220 of the graphene supply unit 200 is continuously supplied by the first conveyor belt 700, graphene transfer of a large area may be possible. The transfer target substrate supply unit 300 including the transfer target substrate 310 may be configured to be spaced apart from the graphene supply unit 200. The second conveyor that can be transferred to the transfer target substrate supply unit 300 in one direction in the vacuum chamber 100 to the lower portion of the transfer target substrate supply unit 300 to continuously supply the transfer target substrate supply unit 300. The belt 710 and the third conveyor belt 720 may be further configured. As 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, the graphene transfer having a large area as described above is performed. It may be possible.

Pressing one surface of the graphene supply unit 200 in a direction in which the graphene supply unit 200 approaches the transfer target substrate supply unit 300 to connect the graphene supply unit 200 and the transfer target substrate supply unit 300. A first roller 610 to be bonded may be configured on the graphene supply unit 200. In addition, a second roller 620 for pressing the transfer target substrate supply 300 in a direction in which the graphene supply unit 200 approaches the transfer target substrate supply 300 is an upper portion of the transfer target substrate supply 300. Can be configured. The graphene supply unit 200 and the transfer target substrate supply unit 300 are bonded to each other in a straight line by the first roller 610 and the second roller 620, and the graphene 220 and the graphene are transferred when the graphene transfer is performed. The bonding force of the transfer target substrate 310 can be further improved.

In a typical roll-to-roll type graphene transfer device, graphene transfer has been performed by applying a low temperature or applying mechanical pressure to use a thermal release tape. However, in the present invention, by configuring a graphene transfer device for vacuum heat treatment, it is possible to remove impurities between the graphene and the substrate to be transferred in a vacuum atmosphere composition at the time of graphene transfer, and to configure a heater By supplying heat during the pin transfer process, the graphene may be transferred to the transfer target substrate by spontaneous bonding between the graphene and the transfer target substrate.

Referring to FIG. 5, the graphene transfer device of the present invention includes a vacuum chamber 100 and a graphene 220 on an upper portion of a transfer target substrate supply unit 300 including a transfer target substrate 310 in the vacuum chamber 100. The graphene supply unit 200 including the support substrate 210 is disposed, and the graphene supply unit 200 and the transfer target substrate supply unit 300 may be adhered to each other by the first roller 600. have. In addition, a heat supply unit including a heater 410 that provides heat to the transfer target substrate 310 is positioned below the transfer target substrate supply unit 300. A stage moving device 440 is disposed below the heater 410, and the stage moving device 440 may perform three-dimensional movement of the transfer target substrate supply unit 300 in the XYZ axis direction. The large area graphene transfer process may be optimized by adjusting a distance and a position between the transfer target substrate and the graphene supply unit through vertical movement of the first roller 600 and three-dimensional movement of the stage shifting device 440. .

Thus, the transfer of the graphene according to the graphene transfer device of the present invention, may have the effect of increasing the adhesion between the graphene and the substrate to be transferred, may have the advantage of ensuring the inherent characteristics of the graphene as it is. . In the conventional roll-to-roll type graphene transfer device, due to the low temperature, the adhesion between the graphene and the substrate to be transferred is not sufficient, and the graphene may be damaged by impurities during the graphene transfer process performed at normal pressure. This may mean that the graphene transcription state is improved by minimizing possible factors.

[실시예] EXAMPLE

Example 1

PMMA, which is an adhesive layer, was coated on the graphene synthesized on a copper foil, which is a catalyst metal, by using a spin coating method. The adhesive layer PMMA was cured in an oven or the like and bonded to a PEN substrate having a 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, in order to remove copper, which is a catalyst metal of the graphene laminate, the copper was removed by contacting an etchant containing FeCl ₃ , HCl, and DI water (distilled water) at a temperature of 50 ° C. for 5 minutes. In order to wash the residue remaining in the graphene, soaked in HCl solution for 20 minutes, and then immersed in DI water solution for 1 hour. The graphene laminate from which the catalyst metal was removed was brought into contact with a hydrophilic SiO ₂ substrate prepared as a transfer target substrate, and the graphene was transferred by performing a vacuum heat treatment at a temperature of 200 ° C. in a vacuum atmosphere of 10 ⁻² torr. Thereafter, the PEN substrate was removed, and the PMMA was removed with acetone to obtain graphene transferred onto the transfer target substrate.

In addition, graphene was transferred onto the transfer target substrate without vacuum heat treatment for comparison to make a comparative example.

Figure 6 (a) is an image showing the Raman spectrum of the graphene transferred in accordance with Example 1 of the present invention, Figure 6 (b) is a Raman mapping of the graphene transferred to the graphene of Example 1 without vacuum heat treatment ( Raman mapping) is a comparison image.

Referring to Figure 6 (a), it can be seen that the surface of the graphene transferred in accordance with Example 1 of the present invention is cleanly transferred without wrinkles or cracks. Looking at the Raman spectrum through Raman spectroscopy for each region by dividing the point ¹ to point 5 of the graphene, overall, D peak (peak) at around 1350cm ^-1 , G peak at around 1580cm ^-1 , 2680cm ^It can be seen that a 2D peak is observed around ^-1 . This is similar to that found in the Raman spectrum of general graphene, and through this, heat transfer in a low vacuum atmosphere according to Example 1 of the present invention is performed to transfer the graphene, which retains the crystallinity originally possessed by graphene. You can see that went well.

The degree of defects of graphene may be known through the intensity ratio (I _{D / G} ) of the D peak and the G peak, and a lower value may mean a good quality graphene. In Fig. 6 (a), the intensity of the D peak is very weak, and it can be seen that the graphene transferred by vacuum heat treatment according to Example 1 of the present invention has less defects in graphene crystals and better quality. This shows that the transfer state of graphene is improved by removing impurities that may affect the surface of graphene by preventing heat or oxygen from contacting with the vacuum composition while performing heat treatment under vacuum atmosphere during the transfer of graphene. have.

Referring to FIG. 6 (b), it can be seen that the left image is a Raman mapping result of graphene transferred without vacuum heat treatment, and the position of the G peak is changed to 1590 cm ⁻¹ to 1602 cm ⁻¹ . This is because the dopants such as water may remain during the wet process based on distilled water for etching the catalyst metal during the transfer of graphene, and thus, the graphene is doped with G-peak This may mean that the position of is changed. The image on the right is a Raman mapping result of the graphene of Example 1 of the present invention, which maintains the G peak area of general graphene 1580 cm ⁻¹ to 1590 cm ⁻¹ , and transfers the graphene through vacuum heat treatment. It can be seen that the characteristics of the pin were maintained as it is.

FIG. 7 is an image comparing the state in which graphene transferred through vacuum heat treatment and graphene transferred without contacting distilled water (DI Water) according to Example 1 of the present invention are not subjected to vacuum heat treatment.

Referring to FIG. 7, the right region of the image is contacted with distilled water (DI Water) with transferred graphene without performing a vacuum heat treatment, and then the transferred graphene is almost separated. Thus, it can be seen that the graphene transferred without vacuum heat treatment may be easily damaged since the adhesion with the substrate is not high. On the contrary, the left region of the image is graphene transferred through vacuum heat treatment according to Example 1 of the present invention, and it can be seen that there is no change in the state of the transferred graphene even after contact with distilled water (DI Water). Through this, it can be seen that the graphene transferred through the vacuum heat treatment of the present invention has high adhesive strength with the substrate, so that the characteristics and quality of the graphene can be maintained intact. It may also be advantageous to fabricate the used device.

Example 2

Except that the heat treatment was performed at a temperature of 175 ℃ when performing the vacuum heat treatment in the same manner as in Example 1 to obtain a transfer graphene.

Example 3

Except that the heat treatment was carried out at a temperature of 190 ℃ when performing the vacuum heat treatment in the same manner as in Example 1 to obtain a transferred graphene.

Example 4

Except that the heat treatment was performed at a temperature of 195 ℃ when performing the vacuum heat treatment in the same manner as in Example 1 to obtain a transfer graphene.

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 The graph shows an attached area of graphene on a substrate to be transferred at a temperature of 175 ° C. It can be seen that the contact area of the graphene is formed only on a portion of the substrate to be transferred. FIG. 8 (b) shows that the attached area of the graphene on the transfer target substrate is further enlarged in the process of increasing the temperature to 200 ° C. according to Example 1 under a 10 ⁻² torr vacuum atmosphere. This is because, by performing the 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 thus the adhesion between the graphene and the transfer target substrate It can be seen that increasing the transfer state of graphene by increasing the. In addition, due to the vacuum atmosphere, immediately before the graphene is transferred to the transfer target substrate, water or oxygen such as water or oxygen between the graphene and the transfer target substrate or impurities which may cause doping to the graphene may be removed. Therefore, the factors affecting the quality of graphene during graphene transfer can be minimized.

Referring to FIG. 9, it can be seen that as the heat treatment temperature of the vacuum heat treatment during transfer increases, graphene is evenly transferred onto the substrate without foreign matter between the graphene and the substrate to be transferred. As described above, it can be seen that spontaneous bonding between the graphene and the substrate to be transferred is induced by vacuum heat treatment during graphene transfer, thereby increasing the bonding force of the graphene to the substrate to be transferred.

Example 5

The graphene transferred according to Example 1 was contacted with acetone and subjected to ultrasonic sonication for 1 minute. The ultrasonic pulverization may be used by a method of washing or destroying a cell or an intracellular structure using a sound wave of 10 kHz to 20 kHz.

Referring to FIG. 10, it can be seen that acetone is dispersed and the surface of the transferred graphene is clearer while ultrasonic grinding is performed together with acetone. This may mean that the quality of graphene is improved as the residue of PMMA, which is an adhesive member remaining on graphene, is removed by dispersed acetone. In addition, it can be seen that only the residue of the adhesive member is removed during the ultrasonic pulverization and that the crystal of the graphene is not changed, thereby increasing the adhesion between the graphene and the substrate to be transferred by the vacuum heat treatment of the present invention.

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 thus, the present invention does not apply a process using ultrasonic waves. In addition to the increase, it is possible to have an ultrasonic process capable of improving the quality of the graphene to have the effect of maintaining the characteristics of the graphene in the graphene transfer process.

FIG. 11 is a graph comparing the results of Raman spectroscopy of each graphene of Example 4 without ultrasonic grinding and Example 4 with ultrasonic decomposition.

Referring to FIG. 11, it can be seen that there is no significant change in the image of graphene at points 1 to 2 before and after the ultrasonic grinding, and there is no significant change in the Raman spectrum according to the ultrasonic grinding of Example 4. As described above in FIG. 4, since the crystallinity of the graphene is well maintained even after ultrasonic grinding, it can be seen that the bonding force between the graphene and the substrate to be transferred is high.

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 manufactured. In Comparative Example 1, a FET to which graphene was transferred without vacuum heat treatment was applied.

Referring to FIG. 12, in the case of the FET device to which the graphene is transferred using the vacuum heat treatment of the present invention, a dirac point is measured near 0 V and shows symmetrical data based on the dirac point. have. On the contrary, in the case of the FET device to which the graphene is 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, when performing the transfer process of the graphene transferred without vacuum heat treatment, the transfer condition is changed by dopants such as water or oxygen between the graphene and the substrate to be transferred, thereby maintaining the graphene characteristics. It can be seen that this also affects the electrical characteristics of the FET device to which it is applied.

Example 7

The graphene transferred according to Example 1 was included as a channel layer, and a photo detector including a drain electrode, a source electrode, and a gate electrode was manufactured. In Example 1, as a comparative example, a photo detector to which graphene was transferred without vacuum heat treatment was applied.

Referring to FIG. 13, in the case of the photodetector to which graphene is transferred using vacuum heat treatment according to Example 1 of the present invention, a comparative example graphene transferred to 1395.9 nA without vacuum heat treatment under the same electric field conditions It was measured that more than 4 times photo current was generated than the 385.9 nA of this applied photo detector. This, it can be estimated that the electron mobility of the graphene is reduced by hole doping during transfer of the graphene transferred without vacuum heat treatment as described above in FIG. It can also be seen that the decrease. Through this, in the case of the graphene transferred by using the vacuum heat treatment of the present invention by removing the elements that affect the doping (duping) by vacuum to ensure the intrinsic characteristics of the graphene (approximately) performance of the device applied to this It can be seen that the improvement.

Example 8

The transfer target substrate was subjected to the same experiment as in Example 1 except that a hydrophobic substrate, hexamethyldisilazane (HMDS), was used to obtain a transferred graphene. For the comparative example, transferred graphene was prepared on the same HMDS substrate as the transfer target substrate without using vacuum heat treatment.

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

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

On the other hand, the right image is a graphene transferred onto the HMDS substrate, which is a hydrophobic substrate using vacuum heat treatment, and it can be seen that the graphene is cleanly transferred without wrinkles or cracks. Through this, since the adhesion proceeds by spontaneous bonding of the graphene and the substrate by vacuum heat treatment on the hydrophobic substrate of the present invention, it can be seen that the graphene is uniformly transferred without being affected by the substrate's substrate properties.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are merely presented specific examples to aid understanding, and are not intended to limit the scope of the present invention. It is apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

Claims

Preparing a graphene laminate in which a support substrate and graphene are combined; And

And transferring the graphene of the graphene laminate to the transfer target substrate by vacuum heat-treating the graphene stack and the transfer target substrate.
The method of claim 1,

The support substrate has one or more separation space, the graphene transfer method of the graphene, characterized in that disposed in the separation space of the support substrate.
The method according to any one of claims 1 and 2,

The support substrate may be acid resistant at pH 3 or lower, or basic resistance at pH 10 or higher; And

Transfer method of graphene, characterized in that the substrate having a heat resistance at 100 ℃ to 300 ℃.
The method of claim 1,

Graphene transfer method comprising a bonding member for bonding the support substrate and the graphene.
The method of claim 4, wherein

And 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 bond the support substrate to the graphene.
The method of claim 5,

The adhesive member has an acid resistance of pH 3 or less or a basic resistance of pH 10 or more; And

Transfer method of graphene, characterized in that the adhesive member having a heat resistance at 100 ℃ to 300 ℃.
The method of claim 1,

Transferring the graphene of the graphene laminate to the transfer target substrate by vacuum heat treatment of the graphene laminate and the transfer target substrate,

The graphene laminate and the transfer target substrate is a graphene transfer method, characterized in that performed by applying a heat treatment at a temperature of 150 ℃ to 250 ℃ in a vacuum atmosphere of 10 -7 torr to 10 -2 torr.
In the vacuum chamber,

A graphene supply unit providing graphene disposed on one side of the support substrate;

A transfer target substrate supply unit positioned to be spaced apart from the graphene supply unit and providing a transfer target substrate to which the graphene is to be transferred; And

And a heat supply unit positioned below the transfer target substrate supply unit to provide heat to the transfer target substrate.
The method of claim 8,

The graphene supply unit,

The graphene transfer device, characterized in that the graphene is attached to the support substrate by an adhesive member consisting of graphene / adhesive member / support substrate.
The method of claim 8,

The graphene transfer device,

The apparatus may further include a position control device disposed on a side surface of the heat supply unit and the transfer target substrate supply unit.

The graphene transfer device, characterized in that the separation distance of the graphene supply unit and the transfer target substrate supply unit is adjusted by the position control device.
The method of claim 8,

The graphene transfer device,

Further comprising a stage moving device is disposed below the heat supply,

And a three-dimensional movement of the transfer target substrate supply unit by the stage shifting device.
The method of claim 10,

The graphene transfer device,

And a first roller which presses one surface of the graphene supply unit to bond the graphene supply unit and the transfer target substrate supply unit.
The method of claim 8,

The graphene transfer device,

Graphene transfer device further comprises a conveyor belt for continuously supplying the graphene supply unit and the transfer target substrate supply unit.
The method of claim 13,

The graphene transfer device,

And a second roller pressurizing one surface of the graphene supply unit to press the graphene supply unit and the transfer target substrate supply unit and a second roller pressurizing one surface of the transfer target substrate supply unit. Device.