Method for manufacturing graphene having three-dimensional corrugated geometry

Abstract

The technical idea of the present invention provides a method for manufacturing graphene, the method comprising: a step of fixing, with a pair of holders, both ends of a first polymer layer elongated in a longitudinal direction; a step of stretching the first polymer layer by moving the pair of holders away from the center of the first polymer layer in the longitudinal direction; a step of hardening the upper side of the stretched first polymer layer; a step of placing graphene having a second polymer layer disposed on the upper surface thereof onto the stretched upper surface of the first polymer layer; a step of separating the second polymer layer from the upper surface of the graphene; and a step of moving the pair of holders close to the center of the stretched first polymer layer to corrugate the surfaces of the stretched first polymer layer and the graphene, wherein, in the step of corrugating the surfaces of the stretched first polymer layer and the graphene, the graphene has three-dimensional corrugated geometry in which valleys and ridges having a height difference are repeatedly arranged in a zigzag form along the longitudinal direction.

Description

Method for producing graphene with a three-dimensional wrinkled geometry

[0001] The technical idea of ​​the present invention relates to a method for producing graphene having a three-dimensional wrinkled geometry.

[0002] The recent COVID-19 pandemic has dramatically increased the need for rapid and accurate sensors for detecting biological substances such as DNA and RNA. While a variety of optical, mechanical, and electrical methods have been developed to detect biological substances, most sensors require extensive preprocessing to increase the concentration of the target substance in the solution. In particular, for patient samples such as cancer cells, viruses, and antibodies, the number of extractions from patients is limited, resulting in significantly smaller sample volumes. Furthermore, detection of the target substance requires lengthy and complex preprocessing. Among these, electrical sensors offer high sensitivity without the need for preprocessing to increase the target substance concentration in the solution, and thus, significant research is currently underway.

[0003] Graphene, a two-dimensional hexagonal carbon structure, has recently been actively researched worldwide as a new material that can replace semiconductors. Furthermore, graphene possesses electrically semi-metallic properties, yet because its internal charge acts as a zero-effective mass particle, it is known to possess extremely high electrical conductivity (an intrinsic electron mobility of 20,000 cm2 / Vs). In particular, since the discovery of field-effect characteristics when graphene, a two-dimensional hexagonal carbon atom structure obtained by mechanically exfoliating graphite, was used in transistors, graphene has been attracting attention as a material that can replace conventional semiconductors such as silicon. Accordingly, extensive research is being conducted on technologies that enhance the selectivity and sensitivity of biosensors containing graphene while maintaining the inherently excellent electrical conductivity of graphene. Furthermore, techniques for rapidly modifying the graphene surface and stably immobilizing bioreceptors without additional chemical reaction steps are being developed.

[0004] The technical idea of ​​the present invention aims to solve a problem by providing a method for manufacturing graphene having a three-dimensional wrinkled geometry.

[0005] In order to solve the above problem, the technical idea of ​​the present invention includes the steps of: fixing both ends of a first polymer layer elongated in the longitudinal direction with a pair of holders; moving the pair of holders away from the center of the first polymer layer in the longitudinal direction to elongate the first polymer layer; hardening the upper surface of the elongated first polymer layer; placing graphene having a second polymer layer disposed on the upper surface on the upper surface of the elongated first polymer layer; separating the second polymer layer from the upper surface of the graphene; and moving the pair of holders closer toward the center of the elongated first polymer layer to crumple the surface of the elongated first polymer layer and the graphene, and in the step of crumpling the surface of the elongated first polymer layer and the graphene, the graphene has a three-dimensional wrinkled geometry in which valleys and peaks having a height difference are repeatedly arranged in a zigzag shape along the longitudinal direction.

[0006] According to one embodiment, a method for producing graphene having a three-dimensional wrinkled geometry is provided, characterized in that the step of curing the upper surface of the first polymer layer that has been stretched comprises curing only the upper surface of the first polymer layer by treating it with oxygen plasma.

[0007] According to one embodiment, a method for producing graphene having a three-dimensional wrinkled geometry is provided, characterized in that in the step of settling the graphene on the upper surface of the stretched first polymer layer, the graphene has a flat geometry.

[0008] According to one embodiment, a method for manufacturing graphene having a three-dimensional wrinkled geometry is provided, characterized in that, in the step of settling the graphene on the upper surface of the stretched first polymer layer, the graphene is maintained in a state of being settling on the upper surface of the stretched first polymer layer for 8 to 16 hours.

[0009] According to one embodiment, a method for producing graphene having a three-dimensional wrinkled geometry is provided, characterized in that, in the step of separating the second polymer layer from the upper surface of the graphene, the second polymer layer is separated with a solution containing acetone.

[0010] According to one embodiment, a method for producing graphene having a three-dimensional wrinkled geometry is provided, characterized in that, in the step of separating the second polymer layer from the upper surface of the graphene, the second polymer layer is immersed in a solution containing acetone for 20 to 180 seconds, and then the second polymer layer is separated.

[0011] According to one embodiment, a method for manufacturing graphene having a three-dimensional wrinkled geometry is provided, characterized in that in the step of elongating the first polymer layer by moving the pair of holders away from the center of the first polymer layer in the longitudinal direction, the elongated first polymer layer is elongated by 1.1 to 1.3 times in the longitudinal direction compared to the first polymer layer in the initial state.

[0012] According to one embodiment, a method for producing graphene having a three-dimensional wrinkled geometry is provided, characterized in that the first polymer layer includes polydimethylsiloxane (PDMS) and the second polymer layer includes polymethylmethacrylate (PMMA).

[0013] According to one embodiment, a method for manufacturing graphene having a three-dimensional wrinkled geometry is provided, characterized in that, in the step of crumpling the surface of the extended first polymer layer and the graphene, a height difference between the valleys and the peaks of the graphene is in the range of 10 nanometers to 1000 nanometers.

[0014] According to one embodiment, a method for producing graphene having a three-dimensional wrinkled geometry is provided, characterized in that, in the step of crumpling the surface of the extended first polymer layer and the graphene, the grooves of the graphene are regularly arranged along the longitudinal direction according to a wavelength ranging from 0.1 micrometers to 10 micrometers.

[0015] A method for manufacturing graphene with a three-dimensional wrinkled geometry according to the technical concept of the present invention comprises the steps of curing the upper surface of a polymer layer while stretching the polymer layer, and then depositing graphene on the upper surface of the cured polymer layer. Thereafter, by shrinking the stretched polymer layer again, the graphene can be easily crumpled together with the polymer layer.

[0016] The effects of the present invention are not limited to the effects described above, and effects not mentioned can be clearly understood by a person skilled in the art to which the present invention pertains from this specification and the attached drawings.

[0017] Figure 1 is a cross-sectional view illustrating the structure of a biosensor including graphene.

[0018] Figure 2 is a drawing for explaining the graphene illustrated in Figure 1.

[0019] Figure 3 is an enlarged view of the Q region of the graphene illustrated in Figure 2.

[0020] FIG. 4 is a flowchart of a method for manufacturing graphene having a three-dimensional wrinkled geometry according to one embodiment of the present invention.

[0021] FIGS. 5A to 5F are perspective views sequentially illustrating a method for manufacturing graphene having a three-dimensional wrinkled geometry according to one embodiment of the present invention.

[0022] FIG. 6 is an image taken by an electron microscope of graphene manufactured according to a method for manufacturing graphene having a three-dimensional wrinkled geometry according to one embodiment of the present invention.

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below and may be embodied in various other forms. The following embodiments are provided not to fully complete the present invention, but rather to fully convey the scope of the present invention to those skilled in the art.

[0024] A biosensor comprising graphene having a three-dimensional wrinkled geometry according to embodiments of the present invention is used for gene expression profiling, genotyping, detection of mutations and polymorphisms such as SNPs (Single Nucleotide Polymorphisms), protein and peptide analysis, screening of potential drugs, development and manufacturing of new drugs, etc. by analyzing target substances contained in a sample.

[0025] A biosensor is equipped with appropriate probes depending on the target biological sample to be analyzed. Examples of probes that can be equipped in a biosensor include DNA probes, enzymes or antibodies / antigens, protein probes such as bacteriorhodopsin, microbial probes, and neuronal probes. A biosensor manufactured in the form of a chip is also referred to as a biochip. For example, depending on the type of probe equipped, the biochip may be referred to as a DNA chip, protein chip, cell chip, neuron chip, etc. A biosensor according to some embodiments of the present invention may include an oligomer probe as a probe. The oligomer probe implies that the number of monomers of the probe employed is at the oligomer level. Here, the term "oligomer" may be used to mean a polymer composed of two or more covalently bonded monomers and having a molecular weight of about 1000 or less. Specifically, it may include 2 to 500 monomers, and preferably 5 to 30 monomers. However, the meaning of the oligomer probe is not limited to the above number. The monomers constituting the oligomeric probe can be modified depending on the type of biological sample to be analyzed, and can be, for example, nucleosides, nucleotides, amino acids, peptides, etc. Nucleosides and nucleotides can include not only the known purine and pyrimidine bases, but also methylated purines, methylated pyrimidines, acylated purines, or acylated pyrimidines. Furthermore, nucleosides and nucleotides can include not only the conventional ribose and deoxyribose sugars, but also modified sugars in which one or more hydroxyl groups are substituted with halogen atoms or aliphatics, or functional groups such as ethers and amines are bonded. Amino acids can be L-, D-, and nonchiral amino acids found in nature, as well as modified amino acids, or amino acid analogs.A peptide refers to a compound formed by an amide bond between the carboxyl group of an amino acid and the amino group of another amino acid. Unless otherwise specified, the probes exemplified in the examples below are DNA probes, which are oligomeric probes covalently bonded with monomers of 5 to 30 nucleotides. However, the present invention is not limited thereto, and it is apparent that various probes described above can be applied.

[0026] Figure 1 is a cross-sectional view illustrating the structure of a biosensor including graphene.

[0027] Referring to FIG. 1, a biosensor (10) according to one embodiment may include a substrate (100), an insulating layer (110), a wiring structure (112), a gate electrode (114), a source electrode (116), a drain electrode (118), and graphene (210).

[0028] The substrate (100) may include a base structure made of a material such as silicon. In some embodiments, the base structure may include a complementary metal-oxide semiconductor (CMOS). The substrate (100) may include a semiconductor material, for example, a group IV semiconductor, a group III-V compound semiconductor, or a group II-VI oxide semiconductor. For example, the group IV semiconductor may include silicon (Si), germanium (Ge), or silicon-germanium. The substrate (100) may be provided as a bulk wafer or an epitaxial layer. In other embodiments, the substrate (100) may include glass or a polymer. In yet other embodiments, the substrate (100) may include a silicon-on-insulator (SOI) substrate or a germanium-on-insulator (GeOI) substrate.

[0029] According to one embodiment, an insulating layer (110) may be disposed on the substrate (100). The insulating layer (110) may be formed to have a constant thickness along the upper surface of the substrate (100). The insulating layer (110) may include, for example, an inorganic insulating material, an organic insulating material, or a combination thereof. The inorganic insulating material may include, for example, silicon oxide, silicon nitride, or a combination thereof. The organic insulating material may include, for example, polyimide, epoxy resin, or a combination thereof.

[0030] In one embodiment, the gate electrode (114) can be connected to a power source via a wiring structure (112) to supply a gate voltage to the graphene (210). By observing the electrical parameters of the biosensor according to the gate voltage, the presence of a target substance in the sample can be determined. At this time, a change in the electrical parameters can correspond to the presence of the target substance. For example, the electrical parameters can include capacitance, voltage, average current, etc. The gate electrode (114) can include a conductive metal material. In one embodiment, the gate electrode (114) can be composed of silver (Ag).

[0031] According to one embodiment, a source electrode (116) and a drain electrode (118) may be disposed within the insulating layer (110). The drain electrode (118) may be disposed horizontally spaced apart from the source electrode (116). The source electrode (116) and the drain electrode (118) may be formed of various materials and may include a metal or a metal alloy. For example, the source electrode (116) and the drain electrode (118) may include copper (Cu), ruthenium (Ru), aluminum (Al), cobalt (Co), molybdenum (Mo), titanium (Ti), tantalum (Ta), nickel (Ni), platinum (Pt), chromium (Cr), or an alloy thereof.

[0032] Graphene (210) may be arranged on the upper surface of the source electrode (116) and the drain electrode (118). The graphene (210) may have a three-dimensional wrinkled geometry. A specific description of the structure of the graphene (210) will be described later in the description of FIG. 2. The graphene (210) may be arranged on the upper surface of the insulating layer (110) and may extend horizontally along the upper surface of the insulating layer (110).

[0033] A sample (not shown) in contact with graphene (210) may include a target substance. The sample (not shown) may include a biological solution such as protein, DNA, RNA, fragments having an arbitrary base sequence, blood, or saliva. The sample (not shown) may be placed in a sample storage container (142). The sample storage container (142) may be a container for containing the sample (not shown) and may be made of a polymer or non-polymer material. In the reaction region (130) inside the sample storage container (142), the sample (not shown) including the target substance may react with a probe included in the graphene (210). In one embodiment, the sample storage container (142) may include silicone rubber.

[0034] In one embodiment, the biosensor (10) may further include a well structure (122) disposed on the outer surface of the insulating layer (110) on the upper surface of the insulating layer (110). The well structure (122) may include first and second boundary members (122a, 122b). The first and second boundary members (122a, 122b) may be disposed to be horizontally spaced apart from each other on the upper surface of the insulating layer (110). At least a portion of the upper surface of the graphene (210) may be exposed in a region surrounded by the well structure (122), and a reaction region (130) surrounded by the well structure (122) on the upper surface of the graphene (210) may be defined as a region in which a probe of the graphene (210) can react with a target material. In one embodiment, the well structure (122) may include an insulating material such as silicon oxide or silicon nitride.

[0035] Fig. 2 is a drawing for explaining the graphene illustrated in Fig. 1. Fig. 3 is an enlarged view of the Q region of the graphene illustrated in Fig. 2.

[0036] According to one embodiment, the graphene (210) may include a body (212) in which peaks (P) and valleys (V) having height differences are continuously arranged in a zigzag shape along the length direction, and a probe (214) that is arranged on one surface of the peaks (P) and valleys (V) and is capable of chemically bonding with a target material to be detected. The probe (214) may be arranged not only on the peaks (P) and valleys (V) of the body (212), but also between the peaks (P) and valleys (V).

[0037] In this specification, the longitudinal direction in which the peaks (P) and valleys (V) of the body (212) are repeatedly arranged in a zigzag shape may be defined as the first direction (X direction). The direction that is perpendicular to the first direction (X direction) and in which the peaks (P) or valleys (V) are elongated may be defined as the second direction (Y direction). In addition, the direction that is orthogonal to the first direction (X direction) and the second direction (Y direction) may be defined as the third direction (Z direction). The adjacent peaks (P) and the adjacent valleys (V) of the graphene (210) may be arranged to be spaced apart from each other in the first direction (X direction), and may extend in the second direction (Y direction), respectively. The valleys (V) may be arranged between the adjacent peaks (P) of the graphene (210), and the peaks (P) may be arranged between the adjacent valleys (V). However, the wrinkled shape of the body (212) of the graphene (210) is not limited to that shown in FIGS. 2 and 3, and can be wrinkled into various shapes.

[0038] In one embodiment, the point having the highest level of the body (212) of the graphene (210) that is repeatedly crumpled in a zigzag shape is defined as a peak (P), and the point having the lowest level is defined as a valley (V). In one embodiment, adjacent peaks (P) and adjacent valleys (V) of the graphene (210) may be spaced apart from each other by a constant amplitude (W). The amplitude (W) may be in the range of 0.1 micrometer to 10 micrometers. When the amplitude (W) of the peak (P) is less than 0.1 micrometer, the graphene (210) may be crumpled too tightly, so that sufficient reaction space may not be formed for the probes (214) arranged on one surface of the graphene (210) to chemically bond with the target material (144). When the amplitude (W) of the peak is greater than 10 micrometers, it can be seen that the body (212) of the graphene (210) has a flat geometry rather than a three-dimensionally wrinkled geometry.

[0039] The number of bodies (212) included in the graphene (210) is not limited to that shown in FIG. 2. In another embodiment, the graphene (210) may include a first body and a second body disposed on the first body. From a planar perspective, carbon atoms constituting the first body and carbon atoms constituting the second body may be disposed to overlap each other. In another embodiment, carbon atoms constituting the first body and carbon atoms constituting the second body may be disposed to be misaligned. Since the graphene (210) illustrated in FIGS. 2 and 3 includes one body (212), the expression that the graphene (210) has a three-dimensional wrinkled geometry may have substantially the same meaning as the expression that the body (212) of the graphene (210) has a three-dimensional wrinkled geometry.

[0040] In one embodiment, graphene (210) may have a three-dimensional wrinkled geometry. In the case of flat graphene, a special treatment process, such as a foreign substance doping process, must be performed on the surface of the graphene to open a finite band gap, thereby enabling the graphene to function as a semiconductor. In contrast, graphene with a three-dimensional wrinkled geometry can open a band gap without a foreign substance doping process, thereby enabling the graphene to function as a semiconductor.

[0041]

[0042] Table 1 shows the measured data for the bond lengths between carbon atoms in graphene with a flat geometry and those in graphene with a three-dimensional wrinkled geometry. Referring to Table 1, the bond lengths between specific carbon atoms in graphene with a three-dimensional wrinkled geometry are approximately 1 angstrom longer than the bond lengths between carbon atoms in graphene with a flat geometry. This imbalance in bond lengths between carbon atoms can lead to differences in the electrical behavior of graphene. When graphene with a flat geometry is crumpled into a three-dimensional shape, the symmetry and planarity of the graphene are destroyed, and the peaks and valleys with different heights are arranged continuously in a zigzag pattern along the length direction. This deformation brings about a quantum confinement effect due to the unique electronic structure of graphene, which can be one of the major contributing factors to the opening of the band gap of graphene. In the case of graphene with a flat geometry, the band gap is not opened, so the difference in the amount of current between the state where current flows and the state where current does not flow is only about 20 to 30 times, which makes it difficult to function as a semiconductor device. However, graphene with a three-dimensional wrinkled geometry can open a band gap due to the imbalance in the bond lengths between carbon atoms. Therefore, the difference in the amount of current between the state where current flows and the state where current does not flow can be at least 100,000 times, which can increase the usability of graphene as a semiconductor device.

[0043]

[0044] Table 2 shows the equilibrium state energy of graphene with a flat geometry and the equilibrium state energy of graphene with a three-dimensional wrinkled geometry. Referring to Table 2, the equilibrium state energy of graphene with a three-dimensional wrinkled geometry may be much lower than the equilibrium state energy of graphene with a flat geometry. Therefore, the carbon atoms constituting the graphene with a three-dimensional wrinkled geometry may have higher stability than the carbon atoms constituting the graphene with a flat geometry. The region between the peaks (P) and valleys (V) of the graphene (210) may have more probes (214) than the peaks (P) and valleys (V), and thus may contain many target materials. However, the present invention is not limited thereto, and more probes (214) may be disposed in the valleys (V) and peaks (P) than in the region between the peaks (P) and valleys (V).

[0045] As an example, the distance (d1) from the line (A-A') crossing the center of the graphene (210) to the peak (P) may be 5 nanometers to 500 nanometers. The distance (d2) from the line (A-A') crossing the center of the graphene (210) to the valley (V) may be 5 nanometers to 500 nanometers. Accordingly, the height difference between the peak (P) and the valley (V) may be 10 nanometers to 1000 nanometers. When the distance (d1) from the line (A-A') crossing the center of the graphene (210) to the peak (P) or the distance (d2) from the line (A-A') crossing the center of the graphene (210) to the valley (V) is less than 10 nanometers, the length in the third direction (Z direction) is shortened with respect to the length in the first direction (X direction) of the graphene (210), so that the graphene (210) can be viewed as having a flat geometry rather than a three-dimensionally wrinkled geometry. When the distance (d1) from the line (A-A') crossing the center of the graphene (210) to the peak (P) or the distance (d2) from the line (A-A') crossing the center of the graphene (210) to the valley (V) is greater than 1000 nanometers, the length of the graphene (210) in the third direction (Z direction) becomes longer than the length in the first direction (X direction), so that the graphene (210) may have a densely wrinkled shape. In this case, a reaction space sufficient for the probes (214) arranged on one surface of the graphene (210) to chemically bond with the target material may not be formed.

[0046] According to one embodiment, the probe (214) disposed on one surface of the graphene (210) may be one of a polynucleotide, a peptide nucleic acid (PNA) probe, an aptamer, a protein, an antibody, or a capture agent. The probe (214) may be selected for binding to the target substance (144). For example, when the target substance (144) is DNA, the probe (214) may have a nucleotide sequence complementary to the nucleotide sequence of the DNA to be detected for binding to the DNA.

[0047] When graphene (210) has a three-dimensionally wrinkled geometry, the Debye length is longer compared to when it has a flat geometry, allowing for the capture of more DNA molecules. Therefore, the sensitivity of the probe (214) to the target substance can be increased despite the Debye shielding effect.

[0048] FIG. 4 is a flowchart of a method for manufacturing graphene having a three-dimensional wrinkled geometry according to an embodiment of the present invention, and FIGS. 5a to 5f are perspective views sequentially illustrating a method for manufacturing graphene having a three-dimensional wrinkled geometry according to an embodiment of the present invention.

[0049] Referring to FIG. 5a together with FIG. 4, a method for manufacturing graphene having a three-dimensional wrinkled geometry according to an embodiment of the present invention includes a step (see S110) of fixing both ends of a first polymer layer (310) extending in the longitudinal direction to a pair of holders (322, 324). The pair of holders (322, 324) may be composed of a first holder (322) and a second holder (324). For example, the pair of holders (322, 324) may have a shape of forceps, each having an upper end in contact with a first surface (310a) of the first polymer layer (310) and a lower end in contact with a second surface (310b) of the first polymer layer (310). However, it is not necessarily limited to the shape of the above-mentioned forceps, and any member that can have the function of fixing both ends of the first polymer layer (310) so that the first polymer layer (310) does not shrink can be an example of a pair of holders (322, 324).

[0050] As illustrated in FIG. 5a, in a planar view, the longitudinal direction of the first polymer layer (310) may be defined as a first direction (X direction), and a direction that is perpendicular to the first direction (X direction) and parallel to the first surface (310a) of the first polymer layer (310) may be defined as a second direction (Y direction). In addition, a direction that is orthogonal to the first direction (X direction) and the second direction (Y direction) may be defined as a third direction (Z direction). The first surface (310a) of the first polymer layer (310) is a surface that is orthogonal to the third direction (Z direction) and may be the upper surface of the first polymer layer (310). In addition, the second surface (310b) of the first polymer layer (310) is a surface that is orthogonal to a direction opposite to the third direction (-Z direction) and may be the lower surface of the first polymer layer (310).

[0051] According to one embodiment, the position of the center in the longitudinal direction of the first polymer layer (310) may be defined by a center coordinate (X0) in a first direction (X direction). The first holder (322) may be positioned spaced apart from the center coordinate (X0) in the opposite direction (-X direction) of the first direction. The position of the first holder (322) may be defined by a first coordinate (X1) in the first direction (X direction). The second holder (324) may be positioned spaced apart from the center coordinate (X0) in the first direction (X direction). The position of the second holder (324) may be defined by a second coordinate (X2) in the first direction (X direction). The first coordinate (X1) may be positioned apart from the center coordinate (X0) by a first distance (d1) in the opposite direction (-X direction) of the first direction, and the second coordinate (X2) may be positioned apart from the center coordinate (X0) by a second distance (d2) in the first direction (X direction). In one embodiment, the first distance (d1) and the second distance (d2) may be substantially the same. However, the present invention is not necessarily limited thereto, and in one embodiment, the first distance (d1) and the second distance (d2) may not be the same.

[0052] According to one embodiment, the first polymer layer (310) may include polydimethylsiloxane (PDMS).

[0053] Referring to FIG. 5b together with FIG. 4, a method for manufacturing graphene having a three-dimensional wrinkled geometry according to one embodiment of the present invention includes a step (see S120) of extending a first polymer layer (310) by positioning a pair of holders (322, 324) away from the center coordinate (X0) of the first polymer layer (310).

[0054] As illustrated in FIG. 5b, the first holder (322) may be positioned spaced apart from the first coordinate (X1) in the opposite direction (-X direction) of the first direction. At this time, the position to which the first holder (322) has moved may be defined as the third coordinate (X3) in the first direction (X direction). The second holder (324) may be positioned spaced apart from the second coordinate (X2) in the first direction (X direction). At this time, the position to which the second holder (324) has moved may be defined as the fourth coordinate (X4) in the first direction (X direction). The third coordinate (X3) may be positioned spaced apart from the center coordinate (X0) by a third distance (d3) in the opposite direction (-X direction) of the first direction, and the fourth coordinate (X4) may be positioned spaced apart from the center coordinate (X0) by a fourth distance (d4) in the first direction (X direction). In one embodiment, the third distance (d3) and the fourth distance (d4) may be substantially the same. However, this is not necessarily limited to the above, and in another embodiment, the third distance (d3) and the fourth distance (d4) may not be the same.

[0055] According to one embodiment, the length of the first polymer layer (310) in the first direction (X direction) can be increased by positioning the pair of holders (322, 324) away from the center coordinate (X0) of the first polymer layer (310). The length of the first polymer layer (310) in the first direction (X direction) when the pair of holders (322, 324) are positioned at the third coordinate (X3) and the fourth coordinate (X4), respectively, can be 1.1 to 1.3 times the length in the first direction (X direction) when the pair of holders (322, 324) are positioned at the first coordinate (X1) and the second coordinate (X2), respectively. If the length of the first polymer layer (310) in the first direction (X direction) is increased by more than 1.3 times, the stress applied to the first polymer layer (310) may exceed the yield stress of the first polymer layer (310). If a stress exceeding the yield stress is applied to the first polymer layer (310), the first polymer layer (310) undergoes plastic deformation, and thus, it may be difficult to crumple the surface of the first polymer layer (310) through elastic deformation thereafter. In addition, if the length of the first polymer layer (310) in the first direction (X direction) is increased by less than 1.1 times, the degree of elastic deformation recovered by the first polymer layer (310) may be low, and thus, it may be difficult to crumple the surface of the first polymer layer (310) through elastic deformation thereafter.

[0056] Referring to FIG. 5c together with FIG. 4, a method for manufacturing graphene having a three-dimensional wrinkled geometry according to one embodiment of the present invention includes a step of hardening a first surface (310a) of a first polymer layer (310) (see S130).

[0057] According to one embodiment, the step of curing the first surface (310a) of the first polymer layer (310) may include curing the first surface (310a) by treating it with oxygen plasma. When treating the first surface (310a) of the first polymer layer (310) with oxygen plasma, a very thin oxide film may be formed on the first surface (310a) of the first polymer layer (310). The hardness of the oxide film may be higher than the hardness of the first polymer layer (310) before the oxygen plasma treatment. For example, since the first polymer layer (310) may include polydimethylsiloxane, the oxide film may include silicon oxide formed by a reaction between silicon and oxygen of the polydimethylsiloxane.

[0058] In an oxygen plasma atmosphere, the second surface (310b) of the first polymer layer (310) may also be treated with oxygen plasma. However, since the oxygen plasma may have a certain directionality, the oxygen plasma treatment effect on the second surface (310b) may be weaker than that on the first surface (310a). For example, in FIG. 5c, since the oxygen plasma has a directionality opposite to the third direction (-Z direction), the oxygen plasma treatment effect on the second surface (310b) may be weaker.

[0059] Referring to FIG. 5d together with FIG. 4, a method for manufacturing graphene having a three-dimensional wrinkled geometry according to an embodiment of the present invention may include a step (see S140) of settling graphene (200) having a second polymer layer (330) disposed on an upper surface on a first surface (310a) of a first polymer layer (310). According to an embodiment, the second polymer layer (330) may include polymethylmethacrylate (PMMA). The graphene (200) illustrated in FIG. 5d may be graphene having a flat geometry. In the step of settling graphene (200) on the first surface (310a) of the first polymer layer (310), the graphene (200) may be maintained in a state of being settling on the first surface (310a) of the first polymer layer (310) for 8 to 16 hours. If the time that the graphene (200) is maintained in a state of being settled on the first surface (310a) of the first polymer layer (310) is shorter than 8 hours, the adhesion between the first polymer layer (310) and the graphene (200) may not be properly formed, and thus, during the subsequent process of crumpling the first polymer layer (310), the graphene (200) may not be properly crumpled along the first surface (310a) of the first polymer layer (310). If the time that the graphene (200) is maintained in a state of being settled on the first surface (310a) of the first polymer layer (310) is longer than 16 hours, the adhesion between the graphene (200) and the first polymer layer (310) becomes strong, and thus, during the process of transferring the graphene (200) onto a biosensor substrate (for example, 100 of FIG. 1), it may be difficult to remove the first polymer layer (310) from the graphene (200).

[0060] Referring to FIG. 5e together with FIG. 4, a method for manufacturing graphene having a three-dimensional wrinkled geometry according to one embodiment of the present invention may include a step of separating a second polymer layer (330) from the upper surface of graphene (200) (see S150). At this time, the second polymer layer (330) may be dissolved and removed from the upper surface of graphene (200), and a solution including acetone may be used to dissolve the second polymer layer (330).

[0061] In one embodiment, after the second polymer layer (330) is immersed in a solution containing acetone for about 20 to 180 seconds, the solution containing acetone is removed and the second polymer layer (330) can be physically separated. If the time that the second polymer layer (330) is immersed in the solution containing acetone is shorter than 20 seconds, the second polymer layer (330) may not be sufficiently dissolved. In addition, if the time that the second polymer layer (330) is immersed in the solution containing acetone is longer than 180 seconds, a large amount of moisture penetrates into the interior of the second polymer layer (330), so that the surface moisture content and the interior moisture content of the second polymer layer (330) become substantially the same. In this case, the second polymer layer (330) becomes weak against external impact and is easily torn, so there may be difficulties in the process of physically separating the second polymer layer (330) from the graphene (200).

[0062] Even though a significant portion of the second polymer layer (330) has been separated from the upper surface of the graphene (200), if foreign substances decomposed from the second polymer layer (300) still remain on the upper surface of the graphene (200), the graphene (200) on which the foreign substances remain can be immersed in deionized water for about 12 hours to remove the foreign substances.

[0063] Referring to FIG. 5f together with FIG. 4, a method for manufacturing graphene having a three-dimensional wrinkled geometry according to one embodiment of the present invention may include a step (see S160) of positioning a pair of holders (322, 324) toward the center coordinate (X0) of the first polymer layer (310) to wrinkle the surface of the first polymer layer (310) and the graphene (210).

[0064] As illustrated in FIG. 5f, the first holder (322) can be repositioned at the first coordinate (X1), and the second holder (324) can be repositioned at the second coordinate (X2). Since the pair of holders (322, 324) are positioned toward the center of the first polymer layer (310), a portion of the first polymer layer (310) can be elastically deformed. According to one embodiment, since an oxide film is hardly formed on the second surface (310b) of the first polymer layer (310) due to the oxygen plasma treatment, the second surface (310b) can be elastically deformed while maintaining a flat surface. On the other hand, the first surface (310a) of the first polymer layer (310) does not elastically deform due to curing, and the surface area of ​​the first surface (310a) can be maintained substantially constant. The first surface (310a) becomes crumpled due to the difference in surface area with the elastically deforming second surface (310b).

[0065] As the first surface (310a) of the first polymer layer (310) is crumpled, the graphene in contact with the first surface (310a) of the first polymer layer (310) is also crumpled. As a result, graphene (210) having a three-dimensionally crumpled geometry is completed. The graphene (210) illustrated in FIG. 5f may have a three-dimensionally crumpled geometry, unlike the graphene (200) having a flat geometry illustrated in FIGS. 5d and 5e. The graphene (210) having a three-dimensionally crumpled geometry illustrated in FIG. 5f may have substantially the same structure as the graphene (210, see FIGS. 2 and 3) having a three-dimensionally crumpled geometry described with reference to FIGS. 2 and 3.

[0066] FIG. 6 is an image taken by an electron microscope of graphene manufactured according to a method for manufacturing graphene having a three-dimensional wrinkled geometry according to one embodiment of the present invention.

[0067] Referring to FIG. 6, graphene (210) may have peaks (P) and valleys (V) having height differences that are continuously arranged in a zigzag shape along the longitudinal direction. Adjacent peaks (P) or adjacent valleys (V) of graphene (210) may be regularly arranged with a constant amplitude (W) along the longitudinal direction. In FIG. 6, the amplitude (W) is illustrated as being about 1 micrometer, but depending on the embodiment, the amplitude (W) may be in the range of 0.1 micrometers to 10 micrometers. In addition, in FIG. 6, the distance between the peaks (P) and valleys (V) of graphene (210) is illustrated as being 280 nanometers, but depending on the embodiment, the height difference between the peaks (P) and valleys (V) may be in the range of 10 nanometers to 1000 nanometers.

[0068] As described above, exemplary embodiments have been disclosed in the drawings and specifications. While specific terminology has been used to describe embodiments herein, it is intended solely to illustrate the technical concept of the present disclosure and is not intended to limit the scope of the present disclosure as defined in the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible. Therefore, the true technical protection scope of the present disclosure should be determined by the technical concept of the appended claims.

Claims

1. A step of fixing both ends of a first polymer layer extending in the longitudinal direction with a pair of holders; A step of elongating the first polymer layer by moving the pair of holders away from the center of the first polymer layer in the longitudinal direction; A step of curing the upper surface of the first polymer layer that has been extended; A step of placing graphene having a second polymer layer disposed on the upper surface on the upper surface of the first polymer layer; a step of separating the second polymer layer from the upper surface of the graphene; and A step of moving the pair of holders closer to the center of the first polymer layer to crumple the surface of the first polymer layer and the graphene, In the step of crumpling the surface of the first polymer layer and the graphene, A method for producing graphene having a three-dimensional wrinkled geometry in which the above graphene has valleys and peaks with different heights repeatedly arranged in a zigzag shape along the length direction.

2. In paragraph 1, The step of curing the upper surface of the first polymer layer is as follows: A method for producing graphene having a three-dimensional wrinkled geometry, characterized in that only the upper surface of the first polymer layer is hardened by oxygen plasma treatment.

3. In paragraph 1, In the step of settling the graphene on the upper surface of the first polymer layer, A method for producing graphene having a three-dimensional wrinkled geometry, wherein the graphene has a flat geometry.

4. In paragraph 1, In the step of settling the graphene on the upper surface of the first polymer layer, A method for producing graphene having a three-dimensional wrinkled geometry, characterized in that the graphene is placed on the upper surface of the first polymer layer and maintained for 8 to 16 hours.

5. In paragraph 1, In the step of separating the second polymer layer from the upper surface of the graphene, A method for producing graphene having a three-dimensional wrinkled geometry, characterized in that the second polymer layer is separated with a solution containing acetone.

6. In paragraph 5, In the step of separating the second polymer layer from the upper surface of the graphene, A method for producing graphene having a three-dimensional wrinkled geometry, characterized in that the second polymer layer is immersed in a solution containing the acetone for 20 to 180 seconds, and then the second polymer layer is separated.

7. In paragraph 1, In the step of extending the first polymer layer by moving the pair of holders away from the center of the first polymer layer in the longitudinal direction, A method for producing graphene having a three-dimensional wrinkled geometry, wherein the first polymer layer is stretched by 1.1 to 1.3 times in the longitudinal direction compared to the first polymer layer in the initial state.

8. In paragraph 1, The first polymer layer comprises polydimethylsiloxane (PDMS), A method for producing graphene having a three-dimensional wrinkled geometry, characterized in that the second polymer layer comprises polymethylmethacrylate (PMMA).

9. In paragraph 1, In the step of crumpling the surface of the first polymer layer and the graphene, A method for producing graphene having a three-dimensional wrinkled geometry, characterized in that the height difference between the valley and the peak of the graphene is in the range of 10 nanometers to 1000 nanometers.

10. In paragraph 1, In the step of crumpling the surface of the first polymer layer and the graphene, A method for producing graphene having a three-dimensional wrinkled geometry, wherein the grooves of the graphene are regularly arranged along the longitudinal direction according to a wavelength ranging from 0.1 micrometers to 10 micrometers.

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