KR101535455B1 - A X-ray analytical apparatus capable of charging electricity or magnetic force on graphene specimen and an analytical method of Extreme Super-Thin Graphene using the same - Google Patents

Abstract

The present invention relates to an X-ray analyzing apparatus capable of applying electricity and magnetic force to a graphene specimen; and a crystallographic analytical method of extreme ultra thin graphene (thickness is 0.35 nm-3 nm) using the same. The present invention has an effect of X-ray analyzing while applying electricity and magnetic force to a graphene specimen to identify physical properties of a graphene ultra fine thin film which was an unknown area meanwhile.

Description

FIELD OF THE INVENTION [0001] The present invention relates to an X-ray analysis apparatus capable of applying electromagnetic force to a graphene specimen, and an X-ray analysis method for graphen having a very fine thickness using the same. of Extreme Super-Thin Graphene using the same}

The present invention relates to a graphene specimen which can be subjected to X-ray analysis by applying electricity or magnetism to a graphene specimen in order to grasp the physical properties of the graphene microscopic thin film, And a method of crystallographic analysis of ultrafine thin film graphene (thickness: 0.35 nm to 3 nm) using the same.

X-ray analysis methods for materials are very important. Examples of typical X-ray analysis methods include X-ray scattering, X-ray reflection, X-ray absorption, X-ray fluorescence, X-ray morphology and topology analysis (imaging), and X-ray diffraction. Recent advances in equipment technology have enabled X-ray analysis of thin films of several nm thickness and nanograms of a few nanometers in size. However, it is considered that the method of analyzing a monocrystal film of about 3 nm or less and the microscopic thickness of 2 to 3 nm or less and the nanograin of an extreme size is very difficult with current X-ray analysis technology. The approximate thickness of the graphene crystals is 1 layer (3.5 Å or less), 2 layers (~ 7 Å), 3 layers (~ 10.5 Å), 4 layers (~ 14 Å), 5 layers ~ 21 Å) and 7 layers (~ 24.5 Å). In the X-ray analysis of these samples, peaks can not be obtained by conventional XRD measurement methods, and XRD studies on these are almost nonexistent.

Under such circumstances, overcoming the above problems is becoming a next-generation technology roadmap. The reason why this roadmap is so important is that it is possible not only to study the application of these materials to new materials through analysis of ultimate thin films between 0.5 and 3 nm in thickness, but also because their physical properties become a link between atoms / molecules and existing nanomaterials Thickness dependence and size effect), and the origin of the manifestation of material properties.

Korean Patent No. 1042048 "Lead-out device and digital X-ray detection device using the same" Korean Patent Publication No. 2014-0056670 "X-ray Detector and X-ray Detection System ", 2014. 05. 12.

The present invention relates to a graphene specimen which can be subjected to X-ray analysis by applying electricity or magnetism to a graphene specimen in order to grasp the physical properties of the graphene microscopic thin film, (Thickness: 0.35 nm to 3 nm) of the ultra-thin film graphene.

In order to solve the above problem, the present invention uses ultra-thin film graphene, which is a kind of ultra-thin film material. In addition, seven candidate specimens with a clear thickness definition and a thickness difference of about 3.5 nm were derived and X - ray analysis method was established.

(1) Specially derived ultra-thin film graphene specimens are composed of one layer (3.5 Å or less), 2 layers (~ 7 Å), 3 layers (~ 10.5 Å), 4 layers (~ 14 Å) , 6 layers (~ 21 Å), and 7 layers (~ 24.5 Å).

(2) Temperature and humidity, which are environmental factors of the ultrafine thin film graphene specimen, should be maintained at 278 ~ 328 Kelvin (5 ~ 55 ℃) and humidity less than 70% A problem arises.

(3) Specification of the graphene specimen In the present invention, the number of graphene layers is 1 to 10, and the size of the specimen is 0.3 cm x 0.3 cm or more.

(4) The essential X-ray irradiator within the above-mentioned range is a parallel beam X-ray optics, an Array type detector, a ω-2θ measuring method, a Rocking curve measuring method, Rotation method, detector rotation method, graphene transmission X-ray, X-ray crystal diffraction method of graphene crystal, diffraction method of graphene (002) specific crystal plane, and all components of X-ray diffraction apparatus.

Therefore, X-ray analysis of ultra-thin film graphene is possible if the above conditions are satisfied.

The present invention relates to an X-ray analyzing apparatus for satisfying the above-mentioned conditions, " a chamber in which a graphene specimen is placed; An electromagnetic applicator for applying at least one of electricity and magnetism to the graphene specimen in the chamber; An X-ray irradiating device for irradiating the graphene specimen in the chamber with X-rays; And a detecting device for detecting X-rays transmitted through the graphene specimen in the chamber or being reflected or diffracted by being struck by the graphene specimen. The graphene specimen according to claim 1, &Quot;

Electromagnetic waves are waves generated when the electric field and the magnetic field change with time, and propagate from one region to another through the space without a medium. Examples of electromagnetic waves include light, infrared, ultraviolet, radio wave, microwave, megahertz wave, gigahertz wave, terahertz wave, and the like. An electric field with a constant intensity can not create a magnetic field, but a changing electric field creates a magnetic field around the current. The changing magnetic field induces the electric field and the changing electric field induces the magnetic field. Thus, when a change in electric field occurs in one place in a space, a magnetic field is created and the changing magnetic field makes the electric field again. The electric field and the magnetic field that change in this way spread out into space while inducing each other. This is called electromagnetic wave.

These electromagnetic waves have the following properties. The vibration direction of the electric field, the vibration direction of the magnetic field, and the traveling direction of the electromagnetic wave are always perpendicular to each other. At one point in space, the induced electric field and the induced magnetic field change in phase with each other. Electromagnetic waves propagate in a medium-free vacuum with waves traveling by changes in electric field and magnetic field.

The present invention refers to an electric field, a magnetic field, and an electromagnetic wave collectively, and the present invention is not limited to the theoretical study on the relationship between the external electromagnetic field and the graphene, but to the crystallographic structure of the ultrafine graphene through a crystallographic approach. Such studies are expected to play a role in raising the limits of X-ray analysis. Therefore, the specific electromagnetic applicator of the present invention may have a magnetic field applying device, and the magnetic field applying device may have a single pole (N pole or S pole), a positive pole, or a multipole. The magnetic field changes in the magnetic field in proportion to the distance. When a single pole of a magnetic field is applied, a specific position of a parallel, perpendicular or specific angle to the graphen plate can be given. In the case of a unipolar case, the magnetic field is moved from the positive single pole to the opposite pole. In the case of an anode, an N-pole and a S pole may be prepared and a graphen may be placed between the magnetic fields. Also, graphenes can be placed between the magnetic fields pushing between the opposite pole N pole-N pole and the S pole-S pole. One or more magnetic field application devices may be provided on the basis of this principle, or an electromagnet may be used.

Further, the specific electromagnetic applicator of the present invention may be an electric field applying device, and the electric field applying device may be both DC and AC. In addition, the electric field applying apparatus may be provided with a type of providing electromagnetic waves in the form of radio waves or a method of applying electricity directly to the graphene.

The electromagnetic applicator may be configured to apply at least one of an electric field, a magnetic field, a microwave, a megahertz wave, a gigahertz wave, a terahertz wave, an alpha ray, and a synchrotron radiation.

In addition, the electromagnetic induction apparatus may be characterized in that a mono-pole or a poly-pole magnetic field is applied.

Further, the electromagnetic induction apparatus may be configured to apply a radio electric field.

Further, the electromagnetic applicator may be characterized in that a current is directly applied to the graphene sample in a wire form.

Further, the electromagnetic induction apparatus may be configured to apply a DC or AC current.

The X-ray analyzer capable of applying electromagnetic force to the graphene specimen further includes a specimen holder for holding the edge portion of the graphene specimen in the chamber and drawing the graphene specimen held by the chamber in one or more directions .

In this case, the specimen holder may be configured to independently stretch a rim portion holding and holding a pair of opposing edges of the graphene specimen.

Also, the specimen holder may be configured to be capable of fine stretching to stretch the graphene specimen in units of 0.1 Å.

The X-ray analysis apparatus capable of applying electromagnetic force to the graphene specimen may further comprise a specimen holder capable of rotating the graphene specimen about 3 axes (xyz axis).

And the X-ray irradiating device is configured to perform centrifugal rotation in the longitudinal direction and in the transverse direction.

And the X-ray irradiating device irradiates a parallel beam X-ray.

And the detection device is configured to be rotated in the centrifugal direction in the longitudinal direction and in the transverse direction.

The X-ray analysis apparatus capable of applying electromagnetic force to the graphene specimen may further include a heat treatment apparatus for applying heat to the graphene specimen in the chamber.

And an X-ray analyzer capable of applying electromagnetic force to the graphene specimen, the apparatus further comprising a cooling device for cooling the graphene specimen in the chamber.

The X-ray analysis apparatus capable of applying electromagnetic force to the graphene specimen may further include a gas atmosphere forming apparatus for supplying an active or an inactive gas or applying moisture to the graphene specimen in the chamber.

The X-ray analysis apparatus capable of applying electromagnetic force to the graphene specimen may further include a pressure adjusting device capable of pressing or depressurizing the inside of the chamber.

The present invention also provides an X-ray analysis method for graphene having a very fine thickness, comprising the steps of: (a) preparing an X-ray analyzer capable of applying electromagnetic force to the graphene specimen; (b) laying a graphene specimen having 1 to 10 layers and a size of 0.3 x 0.3 cm or more in the chamber; And (c) detecting X-rays transmitted through the X-ray irradiating device by irradiating the X-ray to the graphene specimen, diffracting or reflecting the X-rays, by the detecting device, and applying at least one of electricity and magnetism to the graphene specimen Ray analysis method for graphen having a very fine thickness, comprising the steps of: "

The X-ray irradiation angle and the arrangement of the detecting device in the step (c) may be set by the 2? (Theta) -ω (omega) method.

In the step (c), the angle of the X-ray irradiated on the specimen may be set within a range derived from the following [irradiation angle derivation formula].

[Investigation angle derivation expression]

X-ray irradiation angle = (2? _(Hkl) 2) 占 1 占

2 &thetas; (hkl): Diffraction angle of the peak center of the reference graphene crystal plane having a specific Miller index

In addition, in the step (c), the detection device may be installed within an angle range derived from [the detection angle derivation formula] based on the graphene specimen.

[Detection angle derivation expression]

X-ray detection angle = (2? _(Hkl) ? 2) 占 1

2 &thetas; (hkl): Diffraction angle of the peak center of the reference graphene crystal plane having a specific Miller index

The graphenes of the present invention can be produced by graphene produced by the CVD method and graphene or modifier graphene obtained by physically, mechanically, electrochemically or chemically modifying them, graphene graphene, Chemically oxidized graphite oxide (a kind of graphene) or graphene oxide, graphite oxide or graphene oxide thermally reduced graphene and chemically reduced graphene, expanded graphene (expanded graphite) A graphene nanoplate manufactured from a material which has been expanded due to microwave or energy application), graphene grained by physicochemical or solvent stripping of graphite, graphene grafted in a top-down manner, , Graphene produced based on the catalyst, graphene prepared through decomposition of hydrocarbons, SiC surface So there are formed pin, the graphene encapsulated in nano-particle surfaces, RGO, graphene nano-plate the physical, chemical and electrical changes that the modify-graphene nano-plate or the like.

Also, since it is known that oxygen exists unconditionally on the surface of graphene, the graphene of the present invention has an oxygen content of 5% or less, and sulfur and phosphorus components may be contained by 5% or less through chemical oxidation of graphite have.

Also, the graphene of the present invention may be doped with elements such as boron, phosphorus, sulfur, nitrogen, and fluorine through a conventional doping process.

Further, the graphenes of the present invention may have various groups on the graphene surface through additional chemical reaction, surface treatment or post-treatment, and may have modified substituents. Representative examples may include OH, -COOH, -CONH2, -NH2, -COO-, -SO3-, -NR3 ⁺ , -CH = O, C-OH, It falls in the range of graphite oxides.

The graphene materials of the present invention can be further added in various forms, and the criteria of the present invention are related to the surface oxidizer, the functional group, the functional group, the degree of defect in the basal plane, the modified functional group, the doping element, It is the number of basal plan of 1 ~ 10 layers without.

According to the present invention, an ultrafine film having a thickness of 3 nm or less or an ultrafine film graphene having 1 to 10 layers of layers, which can not be subjected to conventional X-ray analysis and X-ray diffraction analysis, And X-ray diffraction analysis can be performed to obtain crystallographic information on these.

As such material analysis becomes possible, industrial application of graphene, which is regarded as a next generation new material, becomes possible, and crystallographic information and layer number information of unknown graphene can be obtained by using these X-ray analysis information as a reference. Based on this, we can greatly enhance the diversity and reliability of graphene products, reliability of finished products, and product competitiveness.

FIG. 1 to FIG. 3 are schematic views of an X-ray analyzer capable of applying electromagnetic force to a graphene specimen provided by the present invention.
FIG. 4 is a schematic diagram showing that an X-ray irradiation angle and an X-ray diffracted from an ultra-thin film graphene on an X-ray opaque substrate are all located in a semisphere of a specimen upper layer.
[Fig. 5] is a schematic diagram showing that an X-ray irradiation angle with respect to an ultra-thin film graphene on a transmissive substrate and a position of an X-ray transmitted through or diffracted therefrom are all located in a semisphere of a lower specimen.
6 is a graph showing the relationship between the angle of X-ray irradiation and the position of the X-ray transmitted or diffracted from the ultra-thin ultra-thin film graphene on the transmissive substrate in the semispheres of the upper half of the specimen and the lower half of the specimen, ) In the X-ray tube.
[Fig. 7] is a schematic diagram of a method of producing X-ray transmission type graphene or X-ray transmission type graphene specimen.
FIG. 8 is a schematic view of applying electricity or magnetism to a graphene specimen. FIG.
9 to 12 are schematic diagrams for drawing and deforming graphene specimens in various forms for X-ray analysis.
[Fig. 13] is an XRD pattern graph of a sample prepared by laminating a single-layer graphene thin film from 1 to 10 layers by a transfer method (a silicon oxide film is formed on a 1 cm x 1 cm silicon substrate in order to improve the flatness ratio, S1 to S10 are the names of each sample).
[Fig. 14] is a data value in which the (002) peak of [Fig. 13] is analyzed and shown in a table.
[Fig. 15] is a value obtained by analyzing the data in Fig. 14 and determining the absolute number of graphene layers for the samples S1 to S10.
FIG. 16 is a graph comparing the values of FIG. 15 with the theoretical values.
[Fig. 17] is a graph showing (hkl) peaks of the seven-layer graphene found using the GI SAXS method.
[Figure 18] is a rocking curve graph showing the orientation of the graphene crystal.

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

The present invention relates to " a chamber in which a graphene specimen is placed; An electromagnetic applicator for applying at least one of electricity and magnetism to the graphene specimen in the chamber; An X-ray irradiating device for irradiating the graphene specimen in the chamber with X-rays; And a detecting device for detecting X-rays transmitted through the graphene specimen in the chamber or being reflected or diffracted by being struck by the graphene specimen. The graphene specimen according to claim 1, &Quot;

The environment of the chamber can be controlled to a temperature condition of 278 to 328 K and a humidity condition of less than 70%, and the X-ray irradiating device irradiates a parallel beam X-ray.

The chamber is provided with a sample graphene specimen to be analyzed, and a specimen holder capable of rotating the specimen in three axes (xyz axis) can be provided in the chamber. [Reference Fig. 1] below is a schematic diagram of the axis rotation of the graphene specimen in three axes.

[Reference Figure 1]

In addition, the parallel beam X-ray irradiating device may be configured to perform centrifugal rotation in the longitudinal direction and in the transverse direction, and the detecting device may be configured to rotate centrifugally in the longitudinal direction and the transverse direction. [Refer to Fig. 2] below is a schematic diagram of the centrifugal rotation of the parallel beam X-ray irradiating device and the detecting device in the longitudinal direction and the transverse direction.

[Reference Figure 2]

1 is a schematic diagram of an X-ray analyzer capable of applying electromagnetic force to a graphene specimen according to the present invention. The X-ray analyzer capable of applying electromagnetic force to the graphene specimen of FIG. 1 is configured to set the irradiation angle (?) By fixing the parallel beam X-ray irradiator and rotating the graphene specimen unilaterally. The irradiation angle (ω) is the angle between the irradiated X-ray and the graphene specimen. At this time, the detection device is located at an angle 2? (? =?) With respect to the irradiated X-ray. This irradiation angle and the position of the detection device are referred to as 2? (Theta) -ω (omega) method.

The 2θ-ω method is a method in which a parallel beam X-ray irradiator is fixed and a detecting device is moved according to the uniaxial rotation angle of the graphene specimen. The detection device is fixed and parallel beam X-ray irradiation is performed according to the uniaxial rotation angle of the graphene specimen. And a method of moving the apparatus. A schematic diagram of an X-ray analysis apparatus capable of applying electromagnetic force to a graphene specimen in which such a method is implemented is shown in FIG. 2 and FIG.

For example, after the X-ray irradiation angle (?) Is made a very small angle, the detection device can be rotated at a 2? Angle with reference to the X-ray to be irradiated. This method is a GI (Grazing incident) method, and the GI-SAXS method is also applicable. In order to reduce the influence of the strong peak of the substrate, the graphene specimen coated with the graphene on the silicon substrate is fixed to the position where the peak of the graphene (hkl) crystal plane (mainly the (002) peak) There is also a method of changing the angle ([omega]).

In addition, the graphene specimen can be angularly set by three-axis rotation (? (Psi) and? (Pi) in Fig. 1). According to the setting of the 3-axis rotation angle of the graphene specimen, it is possible to secure the X-ray irradiation angle and detector angle with respect to the partial space above the graphene specimen. Thus, diffracted X-rays existing in the upper layer of the graphene specimen can be partially detected.

Ultra-thin graphene In this case, a graphene specimen without substrate can be applied. In other words, it is possible to apply the removed graphene specimen by using the etching technique, and the damage of the graphene specimen can be easily occurred in the measurement process. In this case, the problem can be solved by moving the graphene specimen in a limited manner, and maximizing the degree of freedom of the angle with respect to the X-ray irradiation angle and the position of the detection device. The parallel beam X-ray irradiating device is configured to be rotated in the longitudinal direction and the transverse direction by centrifugal rotation, so that X-rays can be provided for all the spatial coordinates of the specific space. This is because in the present invention, a three-dimensional crystal structure or a specific crystal plane (for example, (002) plane) of an ultra-thin plate graphene specimen, in which the X-ray irradiation angle, the arrangement (angle) of the graphene specimen, And it is necessary to overcome limitations of existing device technologies in order to analyze the difference in the top and bottom crystal planes in the three-dimensional peak shape or the symmetric crystal structure.

Specifically, in the case of a graphene specimen in which a graphene film is formed or arranged on an X-ray non-transmissive substrate, the position of the X-ray diffracted according to the X-ray irradiation angle varies depending on the semispherical (Except for the lower hemisphere of the graphene specimen). Therefore, when the graphene specimen is rotated on three axes (x, y, z) and the parallel beam X-ray irradiating apparatus and the detecting apparatus are capable of centrifugal rotation in the longitudinal direction and the transverse direction, X- It becomes easy.

As another example, in the case of a specimen having a graphene film formed or arranged on an X-ray transmissive substrate, or when the substrate is etched and only a graphene film is used as a graphene specimen (free standing), the position of the transmitted X- As shown in FIG. 5, in the semisphere of the lower portion of the graphene specimen. Even in this case, the graphene specimen is rotated on three axes (x, y, z), and when the parallel beam X-ray irradiating apparatus and the detecting apparatus are capable of centrifugal rotation in the longitudinal direction and the transverse direction, It becomes easy.

On the other hand, when a graphene film is formed or placed on the X-ray transflective substrate, a part of the X-ray is transmitted and a part of the X-ray is reflected (diffracted) so that all the spaces above and below the graphene specimen, The diffracted X-rays can be positioned in the three-dimensional spheres. Even in this case, the specimen is rotated on three axes (x, y, z), and when the parallel beam X-ray irradiator and detector can rotate centrally in the longitudinal and transverse directions, X- .

When applying a specimen using an X-ray transmission type substrate, the material, thickness and transmittance of the substrate should be confirmed. As the X-ray transmission type substrate, a plastic substrate, a ceramic substrate, a porous substrate, and a fiber composite substrate can be selected, and the transmittance according to the thickness of the substrate can be checked before application. Various methods for producing graphene specimens using an X-ray transmission type substrate are shown in FIG.

The electric, magnetic or electromagnetic waves can be applied to the graphene specimen produced by the various methods shown in FIG. 7 as shown in FIG. 8, thereby obtaining the electromagnetic property information of the graphene specimen .

Meanwhile, the X-ray analysis apparatus capable of applying electromagnetic force to the graphene specimen provided by the present invention may further include a heat treatment apparatus for applying heat to the graphene specimen in the chamber, and the graphene specimen in the chamber may be cooled And a gas atmosphere generating device for supplying an active gas or an inert gas to the graphene specimen in the chamber or applying moisture to the specimen. The inside of the chamber may be pressurized or decompressed And a pressure regulating device capable of regulating the pressure of the fluid.

The X-ray analysis apparatus capable of applying electromagnetic force to the graphene specimen provided by the present invention is characterized in that the graphene specimen in the chamber is held at the rim of the specimen, and the specimen for stretching the graphene specimen held by the chamber in one or more directions And may further comprise a holder. In this case, the specimen holder may be configured to independently stretch a rim portion holding and holding a pair of opposing edges of the graphene specimen. The specimen holder may be configured to be capable of fine stretching so as to stretch the graphene specimen in units of micrometers. The micro-stretch driving can be implemented by an ultrafine mechanical device or a stretching device using a piezo material.

The specimen holder is configured to elongate the rim of the graphene specimen in at least one direction. The specimen holder is configured to stretch the graphene specimen horizontally as well as to vertically stretch the graphene specimen, .

[9] to [12] show various examples in which an X-ray analysis apparatus capable of applying electromagnetic force to the graphene specimen according to the present invention includes the specimen holder as a constituent thereof, An example is shown. As in the embodiment of FIG. 9, when the graphene specimen has a quadrangular shape, it is preferable that the specimen holder is configured to hold all the four corners of the graphene specimen and independently extend each of the corners thereof In this case, as can be seen from FIGS. 10 to 12, X-ray analysis can be performed by modifying the graphene specimen in various forms.

The present invention also provides an X-ray analysis method for graphene having a very fine thickness, comprising the steps of: (a) preparing an X-ray analyzer capable of applying electromagnetic force to the graphene specimen; (b) laying a graphene specimen having 1 to 10 layers and a size of 0.3 x 0.3 cm or more in the chamber; And (c) detecting X-rays transmitted through the X-ray irradiating device by irradiating the X-ray to the graphene specimen, diffracting or reflecting the X-rays, by the detecting device, and applying at least one of electricity and magnetism to the graphene specimen Ray analysis method for graphen having a very fine thickness, comprising the steps of: "

In the step (b), various graphene specimens can be placed.

[Fig. 7] (a) schematically shows a method for producing a graphene sample using CVD graphene. To transmit the X-ray, a graphene specimen (A type) in which the bottom part of the substrate is partially empty using a substrate etching technique, a graphene specimen (B type) in which the substrate is completely removed, and a B type specimen Pin type specimen (C type), graphene specimen (D type) manufactured by performing additional partial etching or complete etching on the transfer substrate, or the like can be used. A porous substrate, an etched substrate, a mesh substrate, or the like may be used to enhance the X-ray permeability of the C type graphene specimen.

7 (b) schematically shows a method for producing a graphene specimen using graphene powder or dispersed graphene. Accordingly, in case of graphene powder, a graphene specimen (E type) manufactured by pressing the powder itself (by keeping the film form by the interlayer bonding force), a graphene specimen pressing or coating the graphene powder on an X- (F type), a mesh substrate, a porous substrate, an etched substrate, or the like, and a graphene specimen (G type) obtained by pressing or coating the graphene specimen type). The graphene powders used here include graphene doped with less than 5% oxygen, thermally reduced graphene, chemically reduced graphene, graphene oxide (such as surface oxidizing and modified substituents), ball milling results of graphite, Energy ball milling results, chemically reactive ball milling (ball milling + chemical reactions (liquid and vapor), ball milling + carbon dioxide reaction, etc.), and graphene nanoplates made from expanded graphite. The graphene or graphene oxide containing an oxidizing group can be thermally treated separately to best observe the moment of change of the graphene (002) crystal face.

And physical methods (such as squeezing, pressing, etc.) to place and fix the graphene specimen in the chamber. It can be applied by mechanical methods (screws, etc.), chemical methods (adhesives, pastes, etc.), electromagnetic methods (electrostatic attraction, electrostatic film, etc.) and can be placed and fixed by van der Waals force or magnetic force.

In the step (c), the X-ray diffracted by the Bragg's law can be analyzed. However, a direct transmission type X-ray diffracted by Bragg's law, absorbed X-ray elastic scattering, and an inelastic scattering analysis method are also applicable. For example, X-rays may be applied to a graphene specimen at a constant angle of incidence that does not fit the Bragg law (ie, perpendicular to the graphene specimen plane), and the detector may be placed on the opposite side to analyze the X- have.

As a concrete example, graphene specimens S3 to S6 (the numbers indicate the number of graphene layers) showed an X-ray absorptivity of 0.5 to 1% per graphene layer, Ray absorption properties.

The X-ray irradiation angle and the arrangement of the detection device in the step (c) may be set by the 2? (Theta) -ω (omega) method.

In the step (c), the angle of the X-ray irradiated on the specimen may be set within a range derived from the following [irradiation angle derivation formula].

[Investigation angle derivation expression]

X-ray irradiation angle = (2? _(Hkl) 2) 占 1 占

2 &thetas; (hkl): Diffraction angle of the peak center of the reference graphene crystal plane having a specific Miller index

In addition, in the step (c), the detection device may be installed within an angle range derived from [the detection angle derivation formula] based on the graphene specimen.

[Detection angle derivation expression]

X-ray detection angle = (2? _(Hkl) ? 2) 占 1

2 &thetas; (hkl): Diffraction angle of the peak center of the reference graphene crystal plane having a specific Miller index

Particularly, the step (c) may be performed while stretching the graphene specimen in micrometer units in more than one direction. It has been found that even when the graphene specimens are stretched to about 30%, the interlayer bond in the graphene is not broken, but there is no XRD study yet. However, the specimen holder of the X-ray analysis apparatus capable of applying electromagnetic force to the graphene specimen according to the present invention is capable of gripping and stretching more than one pair of edges of the graphene specimen, thereby enabling researches. A schematic diagram thereof can be seen from [FIG. 9] to [FIG. 12].

As a specific concrete example, a CVD 5-layer graphene specimen transferred to a PET film is placed on a metal plate, and a PET film protective film is placed on the upper end portion of both sides of the graphene specimen (above the side surface of the graphene) Screw), and one side was stretched by about 5% (PET + graphene). As a result of X-ray diffraction measurement, it was found that the interlayer spacing increased by about 3-8% after stretching. This can be explained by the fact that the quality of graphene crystals deteriorates with elongation.

As described above, the X-ray analysis apparatus capable of applying electromagnetic force to the graphene specimen provided by the present invention may further comprise a heat treatment apparatus for applying heat to the graphene specimen in the chamber, The apparatus may further include a cooling device for cooling the pin specimen. The apparatus may further include a gas atmosphere generating device for supplying an active or an inactive gas or applying moisture to the graphene specimen in the chamber, The liquid graphene dispersion may be coated on the substrate and lightly heat-treated with the heat treatment apparatus to remove excess solvent or adsorbed solvent, can do. Also, even if the graphene specimen is susceptible to moisture adsorption or to prevent moisture adsorption, it can be heated within a stable temperature range through the heat treatment apparatus. In addition, the graphene (002) plane can be directly observed while the graphene or graphen oxide materials containing an oxygen group are heat-treated by the above-described heat treatment apparatus. For example, when the graphene oxide was coated on a glass substrate and subjected to heat treatment at 50 ° C to remove excess moisture, the (002) crystal face was located at 2θ = 11.5 ° when measured by the 2θ-ω method. As a result of annealing at 230 ℃, it can be observed that 2θ = 23.3 ℃.

S1 ~ S10  sample

The samples S1 to S10 shown in Fig. 13 are graphene specimens obtained by transferring single-layer film graphenes and laminating them from one layer to ten layers. In order to improve the flatness of graphene crystals, a silicon oxide film is formed on a 1 cm × 1 cm silicon substrate and graphene is transferred thereon. The sample names were named S1 ~ S10 according to the number of layers stacked.

The graphenes physically layered (layer by layer) in the S1 to S10 samples do not form graphene crystals having the same number of layers. The number of physically stacked graphene layers may be equal to or different from the number of layers actually forming crystals (when there is a spatially excited state without forming crystals, the number of stacked layers and the number of crystal layers are different) .

Also, since the lamination process is performed manually at present, there is a high probability that graphene crystals having different numbers of layers are formed in each process even if the same number of layers are stacked. Therefore, the method of measuring the number of graphene layers proposed in the present invention is also necessary in this respect.

Analysis of the XRD patterns for the samples S1 to S10 indicated that the number of graphene layers of each sample was not identical to the number of times of lamination (for example, the number of graphene layers of the S10 sample was 7). As a result, the number of layers of graphene was differently analyzed, and it is concluded that the number of layers of graphene crystals can not be known only by graphene recovery.

In conclusion, [Figure 13] shows the results of X-ray diffraction analysis of crystals according to the thickness of graphene, which is one of the world's first extreme thin films. It provides absolute physical quantities by the number of graphene layers as well as their physical properties, and suggests a way to use them as a reference at any time in the world.

XRD  How to measure

The X-ray analysis method of the present invention described above is summarized as follows.

(1) X-ray irradiation apparatus: Parallel beam X-ray optics

(2) Detector: Array-type detector

(3) Measurement method: 2theta-omega mode, rocking curve measurement method, incidence angle fixing method, GI SAXS, 2D GISAXS method

(4) Graphene specimen: number of graphene layers 1 to 10 layers (thickness: 3 nm or less), size 0.3 × 0.3 cm or more

(5) In order to investigate the degree of deterioration of the ultimate thin film, a heat treatment device and a humidifying device were separately compared and analyzed.

(6) The specimen is configured to rotate in three axes (x, y, z axis), and the parallel beam X-ray irradiator and detector can be rotated in both longitudinal and lateral directions.

(002) Peak fitting method

Peak fitting of multi-layered film graphene (002) peaks was performed using a Gaussian function (G function) and a Lorentzian function (L function). In the present invention, Respectively. However, in addition to these G functions and L function fittings, if there are functions or programs that can satisfy the X-ray diffraction peaks, they may be used. The FWHM and peak center of the XRD peak of the same graphene sample are constant eigenvalues irrespective of the time, place, and XRD device, and some errors may occur due to noise level, peak fitting function, and the like.

Example

[Fig. 13] are graphs showing XRD measurement data for S1 to S10. This measurement data does not mean the corresponding number of layers of S1 to S10. X-ray diffraction (XRD) spectra were prepared by mixing Cu Kα1 (1.540598 Å) and Kα2 (1.544426) at an intensity ratio of 2: 1. The 2θ was 20-50 ° and the step size was 0.016 °. 2theta ) -ω (omega) method. A parallel beam X-ray optics illuminator and an array type detector were attached to X-ray diffraction equipment separately. A parallel beam X-ray mirror optics is used as a specific example of the parallel beam X-ray optics.

FIG. 13 (a) is a graph comparing two samples of S1 and S2. The graphs were almost identical, and no peak shape was found except for the background scattering intensity. The fact that no peaks were observed even though the measurement was performed for a sufficiently long period of time for 30 to 50 minutes in one measurement shows that (002) peaks do not form like graphite (3-layer basic crystal structure).

From (b) to (i) in FIG. 13, the (002) peaks slightly start to appear, and the intensity tends to increase gradually. It can be seen that the precise number of layers of samples S3 to S10 is unknown but forms graphene crystals that are increasingly thick (ie, the number of layers increases). This is the crystallographic information on the thinnest thin film obtained first through the present invention.

The (002) peak information for the samples S3 to S10 is shown in detail in the table of FIG. For peak fitting, the baseline was set to S2. The G function and the L function are used as the peak fitting function, and these are separately shown in [Fig. 14].

Important information that can be obtained from the (002) peak is as follows.

(1) FWHM directly associated with graphene thickness

(2) d ₀₀₂ (obtained from the peak center 2?

(3) Grain thickness {D_One = d₀₀₂ × (N_L-1) or D₂= d₀₀₂ × (N_L)}, Where N_LSilver graphene layer number

14 shows the FWHM values for the samples S3 to S10 using the G function and the L function, and d ₀₀₂ values obtained from the 2θ values, 2θ, which are the peak centers.

Importantly, the FWHM data relating to the graphene thickness, ie, the number of graphene layers, are independent from S3 → S4 → S5 and are decreasing with certain rules.

The FWHM value of the S6 sample is almost the same as that of the S5 sample. The FWHM values of the S7, S8 and S9 samples also have almost the same values, and the S10 sample has the smallest FWHM value independently. This information is very important.

The reason for this is that graphene crystals, like graphite, are found to have only a small amount of the initial (002) peak (FWHM: 4.663-5.06 °) in the S3 sample (S1 and S2 are observed) Information, and the thinnest graphene crystal layer (minimum number of layers) that can be measured by XRD like graphite crystal is three layers.

The S4 sample has relatively stronger intensity than the S3 sample, and the FWHM is independent and sharp (FWHM: 3.207-3.310 °) peak, which is certainly information about the four-layer graphene layer. ).

In addition, the S5 sample is very strong and very sharp (FWHM: 1.798-1.84 °) peak, which is very different from the S4 sample, which is certainly information about graphene where the main crystal is 5 layers (6 layers are not possible in the laminating process) .

The fact that the FWHM value of the S6 sample closely coincides with the value of the S5 sample FWHM reflects that the stacking process of S6 is only effective at about S5, i.e., the S6 sample shows information about the five-layer graphene crystal.

The S7 to S9 samples have similar values, and the FWHM is smaller with a tendency similar to that of the theoretical model, independent of the 5th layer graphene, which reflects the 6th layer graphene.

Finally, the S10 sample shows the strongest peak intensity and peak intensity, which is one step smaller than that of the six-layer graphene, which is information on the graphene seven-layer.

On the other hand, [Fig. 14] Graphene crystals of the number of layers S1 to S10 were determined from the XRD measurement on the rightmost side of the table.

[Figure 15] is a table summarizing the usable values in the x-axis for drawing the calibration curve. When the absolute values of FWHM (°) of the number of graphene layers evaluated in FIG. 14 are taken as the y axis, the x axis can be the number of graphene layers (N _L ), and the graphene thickness D or graphene thickness (1 / D). The graphene thickness (D) may be obtained by the analyte graphene film thickness (D ₁₎ and a maximum outer diameter between the analysis based on the distance the target graphene film thickness (D ₂₎ of the atoms relative to the inter-atomic center distance have.

D ₁ = d ₀₀₂ × (N _L -1) (where N _L is the number of graphene layers)

D ₂ = d ₀₀₂ x (N _L ) (where N _L is the number of graphene layers)

The calibration curve graphs for these are shown in (a), (b) and (c) of FIG. 16, respectively.

The red line (red circled dotted, denoted by Δ) reflects the result of the L function fitting and the blue line (blue triangle dotted, marked with ○) reflects the G function fitting results.

Various other types of calibration curves are possible. Even if the gap between the graphene layers d ₀₀₂ is the same, it may vary slightly depending on the laminating process. Even if the d ₀₀₂ value of the graphite is used as a fixed value, there is no big problem within the error range (See Fig. 16).

The graph of FIG. 16 (d) compares the data obtained by taking the x-axis as 1 / D and the y-axis as FWHM (the graph corresponding to (c) in FIG. 16) and the graph theoretically obtained by the sherrer equation Data. The theoretical sherrer equation becomes a complete linear graph toward the origin as the crystal size increases. On the other hand, in the case of experimental values, the tendency to deviate from the straight line when the number of graphene layers is 3 or 4 is very important data showing that the graphenes of the third and fourth layers, which are two-dimensional crystals, have properties different from general crystals.

In the case of graphene layers 5, 6 and 7, linear behavior toward the origin is shown as a theoretical value. This is also a very important result when the thickness of the unknown graphene specimen is near or greater than 13 Å (5 stories) The graphene thickness can be obtained.

[16] the dotted line shown in (d) of the So as a result of the linear fit for the pin 5 to 7 layers, in the case of a function of a straight line _{D 1 y = 22.358x + 0.220 (} G function fitting) and y = 22.141x +0.191 (L function fitting). For D ₂ , y = 32.743x + 0.062 (G function fitting) and y = 32.427x + 0.089 (L function fitting), where y is FWHM (°) and x is 1 / D. Degree (°) values of the FWHM in the y-axis can be appropriately modified by radians.

In addition to the graphene thickness or number of layers, the size of nanofilms and nanocrystals can be determined within the range of the slope including the error range of these calibration curves (see [Fig. 14] and [Fig. 15]) and the y intercepts obtained at this time. That is, when a straight line is drawn on the basis of the graphene layers 5, 6, and 7, the slope is about 14 to 40 in the error range, and the y intercept is in the range of -2 to 2. If a calibration curve is drawn after defining the error range based on the number of layers 3, 4, and 5, it has a slope and a slice which are quite different from the above values.

Therefore, in order to determine the error range of the graph and the calibration curve of FIG. 16 in the present invention, an important point is to determine the error of the FWHM by the number of graphene layers. In the present invention, the FWHM errors of the samples S 3 to S 7 are set to ± 1.5 °, 1.0 °, 0.5 °, 0.4 ° and 0.4 °, respectively, from the measurement and fitting results of the additional samples. The maximum possible values were 14-30 slopes and -2-2 slopes.

Further, in Fig. 17, the slope and the slice of the maximum possible region were obtained under the assumption that the entire graphene layers 3 to 7 were straight lines. To do this, we define a Plot 2 (y = 12.6x + 1.1) straight line with a maximum slope Plot 1 (y = 82x-4.6) and a minimum slope, Area. At this time, the slope has 12 ~ 82 area and the y section has 1.12 ~ -4.6 area.

Although the range of the calibration curve was specified within various error ranges, the present study shows the absolute FWHM by the number of graphene layers in [Fig. 16]. When these are used as comparison data and unknown graphene is measured, the number of graphene layers can be determined by comparing and analyzing these data. For example, when the value of FWHM with respect to the XRD (002) peak obtained after the growth of the multilayered filmgraffin crystal is 2.5 °, the value of the present invention is 4 layers (3.207 °) and 1.8 layers ˚), which means that it is 4.5-layered. In reality, there is no graphene crystal called the 4.5-layer, but it gives very important information that the average value of the crystals in which there are several layers is 4.5 layers. To date, no such analysis has been provided.

If there is a program that is well suited to XRD peak analysis, the distribution of the number of graphene layers can be determined after evaluating the half-value width of the peaks after separating the peaks from the (002) peak fitting (compared with the present invention). For example, it is possible to separate the multiple peaks from each other without performing a single peak fitting on the sample, to provide information on the number of layers for each FWHM, to derive a crystal amount for each layer as a fitting peak area, 30% for the third floor, 40% for the fourth floor, and 30% for the fifth floor. What can be done in this way is another effect of the present invention.

XRD measurements were performed under conditions similar to or better than this test, which means that if the (002) peak is not observed, the number of graphene layers is one or two.

The rotation angle of the X-ray source, detector, and specimen of the present invention can be rotated in the x, y, and z axes. All of these rotations are possible with current technology, but it is a technique that must be supplemented when analyzing extreme thin films.

In addition, various comparative experiments on sensitive S3 ~ S5 samples were performed, and the experimental results are shown in [Table 1].

The information on the third to seventh layers in [FIG. 13] is a graph when (1) a parallel beam X-ray irradiator and (2) an array-type detector operate simultaneously on the X-ray diffraction apparatus. (002) peak intensities of the S3 to S5 sensitive samples were set at 100, and were compared while changing the device description and measuring conditions. As shown in [Table 1], it can be seen that when the measurement temperature is in the range of 5 to 55 ° C (278 to 328 ° K) in the above two device technologies, there is almost no change in the peak intensity even for the sensitive graphene The range of 5 ~ 8 ℃ and the range of 45 ~ 50 ℃ is about 2%. In the case of rigorous experiment, the range of 8 ~ 45 ℃ is preferable. ).

However, when the temperature of the specimen is below 5 ° C or above 55 ° C, the peak disappears or sharply decreases, which is very important data showing that ultra-thin graphene can change during long-term measurement. Even at room temperature, the (002) peak of ultra-thin graphene disappears or sharply decreases when the humidity exceeds 70%. Such a temperature change (such as a flame temperature, a hot weather) or a humidity range is a condition that can be frequently encountered in a conventional X-ray diffraction experiment. If the (002) peak is not obtained or is extremely weakened, a false interpretation can be obtained. This phenomenon did not occur in existing graphene specimens and is the first phenomenon to be found in very thin graphene.

In Table 1, we compared the focused beam X-ray irradiator and the normal type detector, which are widely analyzed in general nano thin films. When using the focused beam X-ray irradiator, . This is interpreted to be due to the fact that X-rays with good penetrating power are focused (focused) and transmitted through most of the graphene membrane. This phenomenon is not found in the conventional nano thin film analysis and is the first phenomenon to be found in very thin graphene.

Also, when the detector is normal to the X-ray irradiator, no peak appears or becomes weak (see [Table 1]).

Therefore, in the present invention, when the number of layers of the graphene ultrathin film is 1 to 10 layers, it is necessary to use a parallel beam X-ray beam, and the Array type detector functions to increase the reliability of measurement. Also, the temperature should be 5 ~ 45 ℃ (278 ~ 328 ℃) and the humidity should be less than 70% as the measurement condition, even if the condition of the measuring device is good.

Changes in the extreme graphene film at temperatures below 5 ° C and above 55 ° C and above 70% humidity can be explained by very weak van der Waals bond strength between graphene layers. The adsorption of H ₂ O water molecules is usually strong so that the water around graphene adsorbs to the graphene surface and some water molecules permeate between weak graphene layers to weaken the crystallinity of graphene, It can be interpreted that the crystallinity is weakened by affecting the cohesiveness (volume increase) and molecular unit vibration of these adsorbed water.

Also, the above results can predict that the crystal form can be changed more sensitively due to the influence of the gap between the graphenes at the higher or lower temperature of the above-mentioned appropriate temperature range. Therefore, as an extension study, it is possible to study graphene crystals at a very low temperature using extreme high temperature and liquid nitrogen and liquid helium using a heater and an atmosphere heat treatment apparatus. According to the present invention, such a study can be made through a heat treatment apparatus or a cooling apparatus.

Also, the above result can predict that the crystal form can be changed more sensitively due to the influence of the gap between the graphenes at higher humidity than the above-mentioned optimum humidity range. Therefore, as an extension study, it is expected that not only H2O but also small molecules (HCl, HF, etc.) and reactive gas, which can easily permeate between layers of graphene, But the present invention makes it possible to carry out such a study through a gas atmosphere forming apparatus.

In the case of S7 in [Fig. 13], two methods are possible when the parallel beam X-ray is irradiated to the graphene specimen and the measurement method of detecting the X-ray diffracted by the detector is ω (omega) -2theta (theta). That is, the incident angle is fixed and the incident angle is rotated. In the present invention, it is understood that some of the crystal planes of the silicon wafer cause some interference with the graphene (002) peak. It was not easy to observe graphene (002) peaks in the relatively high strength silicon wafer peak when the 4-layer graphene specimen was separately measured with general ω (omega) -2theta (theta). In order to solve this problem, the parallel beam X-ray irradiation angle was fixed at the derived angle according to the next [irradiation angle derivation formula]. Thus, the silicon peak was not emitted and only the graphene (002) peak could be obtained.

[Investigation angle derivation expression]

X-ray irradiation angle = (2? _{( Hkl )} 2) 占 1 占

2 &thetas; (hkl): Diffraction angle of the peak center of the reference graphene crystal plane having a specific Miller index

[Fig. 17] is a graph (2? = 42.525 °) showing a peak for another (hkl) crystal plane other than the (002) peak of graphene number 7 found using the GI SAXS method. This peak can not be found in the usual way. This is because it is not a crystal plane provided on the vertical plane of the thin film. In addition to the crystal vertical plane, there are various peaks on the xy plane of the crystal horizontal plane, and the GI SAXS method is required to find them. In the present invention, a peak other than the (002) crystal face of the seventh layer graphene was found by using this method. Although the hkl index has not yet been determined, the principle of the present invention can be applied to this peak as it is (see d _{( hkl )} and FWHM theory). We will also look for another (hkl) decision through the GI SAXS law, but it takes too long. However, using GI SAXS with 2D GI SAXS, that is, a 2D GI SAXS device, it is possible to find peaks of the graphene xy crystal plane in a short time, and to find the graphene layer number determination information (defect constants) You can get accurate information.

The GI SAXS method is powerful enough to find another peak that is much less intense than the graphene (002) peak. Therefore, in the present invention, the GI SAXS method can also be used for finding the (002) plane of graphene. Further, 2D GISAXS with a 2D detector can more easily detect graphene peaks. The principle of the present invention can be applied to a 3-dimensional (or 2.5-dimensional: partial spatial cover) detector concept to be developed in the future.

[Fig. 18] is a graph of a rocking curve with respect to graphene crystal planes of 3 to 10 layers (S3 to S10). The x-axis is the angle of the omega (°). This rocking curve is a very important measure of how much the (hkl) crystal plane is tilting (tilting, etc.) and how tilted it is. When measuring the rocking curve, the angle of the detector was fixed to the angle derived from the following [Detection angle derivation formula]. After this, the X-ray diffraction intensity was measured while the omega angle was minutely varied from + to -.

[Detection angle derivation expression]

Detector irradiation angle = (2? _{( Hkl )} ) 占 占

2 &thetas; (hkl): Diffraction angle of the peak center of the reference graphene crystal plane having a specific Miller index

The rocking curve with respect to the graphene (002) crystal plane is shown in Fig. 18. [Fig. 18] The center value of the peak is 1/2 of the peak 2? Of the graphene (002) crystal face shown in Fig. 13. 10 layer Grading (S10) Rocking curve When the peak center line of the graph is taken as a reference, the crystal orientation center and distribution of each layer graphene crystal are different (peaks in [Fig. 18] are crystal orientation distribution functions ), The intensity decreases from the center to the edge, indicating the degree of tilt of the crystal plane located at a plane (0 °) where the center of the peak coincides with the xy axis of the crystal. That is, when the x-axis of [Fig. 18] is redrawn, the peak center is 0 °, the left side is an angle tilted to a minus angle, and the right side is an angle tilted to a positive angle. Represents the distribution function of graphene (002) crystal planes existing at an angle. Accordingly, the present invention also provides the first XRD information showing that the two-dimensional graphenes by layer number exist in a form (+, 0, - distribution) rather than a perfect two-dimensional plane.

A vacuum thermal processing system and a cooling system, such as liquid nitrogen, can be placed in the extreme analytical thin film device to maximize the adverse effects at temperatures below 5 ° C and above 55 ° C and above 70% humidity. As shown in [Table 2], in the case of 6-layer graphene, it is possible to observe the change behavior of d ₀₀₂ graphene spacing in vacuum heat treatment. As the temperature increases, the interplanar spacing decreases and becomes larger, which can be interpreted as an increase in crystal quality due to the annealing effect and an increase in interplanar spacing due to molecular vibration at higher temperatures. [Table 2] can also study the interplanar spacing of extreme graphene thin films even in the cooling test using liquid nitrogen. In this case, the interplanar spacing change can be explained by the reduction of the thermal vibration energy of the graphene molecule, the association of the absorbed water molecule, and the solid phase change.

FIG. 14 to FIG. 16 show the FWHM of the number of graphene layers, and it is possible to evaluate the number of unknown graphene layers by using this as a reference. This principle is a technique that has not existed in existing extreme thin films. For example, when the value of FWHM for the XRD (002) peak obtained after the growth of the multilayered filmgraffin crystal is 2.5 °, the value of this graph is 4 layers of graphene (3.207 °) and 1.844 ˚), which means that it is 4.5-layered. Theoretically, there is no graphene crystal called the 4.5-layer, and it provides very important information that the average value of the crystals in which there are several layers is 4.5 layers. To date, no such analysis has been provided. This principle is equally applicable to the various grades mentioned in the introduction (kind, classification, doping, oxygen and sulfur components, surface modifiers, etc.).

It can be seen that when the size of the S3 graphene specimen (1 cm x 1 cm) in Fig. 13 was set to half (0.5 cm x 0.5 cm) in both width and height, the peak completely disappeared. In the case of S5 graphene specimen (1 cm × 1 cm), when the width and height were 0.3 cm × 0.3 cm, the peak disappeared completely. That is, it was found that the crystal peak of the ultimate thin film having the minimum thickness can be obtained only when the size of the graphene specimen is 0.3 to 0.5 cm × 0.5 cm or more. The size of the graphene specimen is preferably as large as possible, but the size of the graphene specimen preferred in the present invention is preferably at least 0.5 cm x 0.5 cm (the larger the number of graphene layers, the smaller the size of the specimen).

The (002) peak was not observed when the omega-2 theta mode used in the S3 specimen measurement in FIG. 14 was measured by a Thrta-2Theta measurement method using a general powder XRD. Therefore, the present invention shows that the ultimate thin film can obtain crystallographic information of the three-layer graphene only when various device options are combined and the environmental measurement conditions and the measurement method are combined at the same time.

The CVD graphene used in the S10 graphene specimen of FIG. 14 was transferred to a metal holder of 8 mm x 8 mm (width x length) and then placed in the center of the X-ray analyzer. The X- After the upper left detector was sent to the lower right side, the irradiated X-ray was measured with omega-2theta after the graphene was placed and the substrate was empty and the FWHM of the (002) crystal face was obtained I got it. The transmittance decrease due to absorption and scattering of graphene specimen itself was about 1 ~ 3.5. The FWHM of the (002) crystal was analyzed and compared with the graphene reference in the previous section, the number of layers was 5.8. Unlike the conventional X-ray reflection method, X-ray scattering method, X-ray fluorescence analysis method, and X-ray diffraction method, such an experiment can be performed by X-ray transmission analysis by transmission, X-ray absorption by transmission, X- Shows that the method is possible in extreme thin film graphene.

The Hummers method, the Brodie method, the Hofman & Frenzel method, the Hamdi method, the Staus method, and the like including the Modified Hummers method can be used as a method for producing the graphene oxide. The Modified Hummers method is used in the present invention. As a specific example, 50 g of micro graphite powder and 40 g of NaNO ₃ are added to ~ 200 mL of H ₂ SO ₄ solution, and ₄ ~ 250 g of KMnO is slowly added over 1 hour while cooling. Then slowly add ₅ L of 4-7% H ₂ SO ₄ over 1 hour and add H ₂ O ₂ . Thereafter, the precipitate was centrifuged and washed with 3% H ₂ SO ₄ -0.5% H ₂ O ₂ and distilled water to obtain a yellowish brown graphene oxide water-based slurry. This was coated on PET to a thickness of 300 nm, dried at 150 ° C, and peeled. The peeled graphene membrane was placed on a metal holder having a size of 8 mm x 8 mm (width x length), and then fixed by using a physical fixing method (covering the cover and screw tightened) And analyzed under the same conditions. The transmittance decrease due to absorption and scattering of graphene specimen itself was about 20 ~ 25. (002) crystal plane was observed near 2? = 12 degrees.

The hot wire was also irradiated by an IR lamp near the holder so that the graphene specimen could be locally heat treated. After 10 minutes, the temperature reached near 400 ° C, indicating that the decrease in X-ray transmittance (or increase in absorption rate) was increased to 10-15. It also shows that there is a very large change in 2θ = around 22 degrees. It is interpreted that the graphene oxide is thermally reduced to graphene, so that the thickness becomes thinner (transmittance decreases) and the interlayer spacing becomes narrower. Investigation of the FWHM of the thermally reduced graphene (002) crystal plane revealed that the number of layers was about 6.4. It can be seen that the number of layers of graphene contained in the graphene powder or graphene dispersion is 1 to 10 layers, and the principle of the present invention is applied, and only the thickness of the sample shows that these graphenes are simply stacked. Therefore, the present invention means that the number of layers is 1 to 10 in the case of CVD graphene and 1 to 10 in the case of graphene powder. Unlike X-ray diffraction, X-ray scattering, X-ray fluorescence, and X-ray diffraction, which are usually analyzed by graphene powder or graphene oxides, this experiment is based on X-ray transmission analysis by transmission, X- And X-ray diffraction by transmission and transmission is possible in extreme thin film graphenes.

Specifically, the chemical reduction method is as follows: 1 g of hydrazine hydrate is added to 2 g of 3% graphene oxide slurry and 100 ml of distilled water is well dispersed. Then, 1 ml of hydrazine hydrate is added and the mixture is reduced at 100 ° C. for 3 to 24 hours. It is filtered with filter paper and washed with water and methanol. A process may be used in which a salt of an alkali metal or an alkaline earth metal such as KI or NaCl is treated to remove H ₂ O beforehand from graphene oxide to partially restore the carbon-carbon double bond before treating a strong reducing agent such as high- . As a specific experimental example, 6 g of KI is added to 5% graphene oxide slurry and left for 6 days to complete the reaction. It is then rinsed with distilled water and filtered. In addition to the hydrazine method and the KI method, there are NaBH4, Pyrogallol, HI, KOH, Lawesson's reagnet, Vitamin C and Ascorbic acid as a method for introducing a reducing agent into other graphene oxide aqueous solution. Analysis of the (002) crystal planes of the graphene produced by reflection and transmission diffraction revealed that the number of layers was 4.8 and 4.7 (FWHM of (002) crystal face), respectively, which is a relatively accurate figure within the error range. In case of X-ray transmittance, only transmission type specimen was available in this experiment. Thus, in order to analyze various extreme thin films using transmission type and reflection type X-ray, the X-ray irradiator, detector, and specimen must be able to move in the x, y, and z axes in the three-dimensional sphere. It is possible to analyze other hidden crystal planes and to analyze low angle transmission method and low angle absorption method and to compare mutual comparison of low angle method (scattering method) (surface roughness, X-ray absorption, fluorescence analysis, etc.) Required).

Although the present invention has been described by way of examples only with respect to X-ray transmission, X-ray absorption, X-ray diffraction by reflection, X-ray diffraction by transmission, diffraction of a specific X- The principle is directly applied to X-ray analysis methods of graphen having a very fine thickness, that is, X-ray diffraction, X-ray diffraction, X-ray penetration, X-ray absorption, X-ray scattering, X-ray fluorescence, .

Hereinafter, specific embodiments in which electromagnetic force is applied and X-ray analysis is performed according to the present invention will be described.

As one embodiment, a CVD 5-layer graphene sample transferred to a PET film was prepared, and then a graphene specimen was placed on the surface of a commercially available 5 cm diameter permanent magnet (FeNd-based), and the distance between the magnet surface and the graphene specimen was separated. Half value width) and the interlayer spacing (d002) were measured. The results are shown in [Table 3]. The surface strength of the magnet was 1.05 T (tesla).

As shown in Table 3, the FWHM (half value width) shows broadening as the unipolar magnetic flux density increases, which means that the crystal becomes unstable. Interestingly, the interlayer spacing (d002) varies with the unipolar magnetic flux density, indicating that the graphene crystal structure changes with electromagnetic field application is never simple. These results are obtained only through the present invention. This result can be explained as a phenomenon that occurs because the surface electron of the graphen having the electrical and magnetic properties that are moving from quantum mechanical to the existing material is changed by the magnetic field applied to the outside. Since the surface electrons of the graphene form a skeleton of the gap between the graphenes and have a great influence on the crystal structure, it can be confirmed from the present invention that the external magnetic field ultimately influences the crystal structure of the graphene.

As another specific example, a CVD 5-layer graphene specimen transferred to a PET film was prepared and then placed on a commercially available 5-cm diameter permanent magnet (FeNd-based) on both sides of the graphene specimen with different poles or the same poles apart. The FWHM (half value width) change rate and the interlayer spacing (d002) change rate of the specimen were measured. The results are shown in [Table 4]. The surface strength of the magnet was 1.05 T (tesla).

From the results in Table 4, it can be seen that the FWHM (half value width) dramatically changes depending on the magnetic flux density, the magnetic field shape, and the magnetic flux intensity depending on the attractive force or repulsion force of the anode. Also, it can be confirmed that the crystal structure of graphene is greatly influenced in an atmosphere in which attraction is applied through the opposite electrode rather than in a single pole. Theoretically, it can be interpreted as a principle that explains the unipolar effect.

As another specific example, after a CVD 5-layer graphene sample transferred to a PET film was prepared, a metal electrode (silver paste) was formed at the edge portion of the graphene specimen, and FWHM (half value width ) And the rate of change of interlayer spacing (d002) were measured. The results are shown in Table 5.

The results shown in the above Table 5 show that, when a current flows regardless of the direct current and the alternating current, the crystal structure of graphene is greatly influenced, and a large change can be made in the FWHM (half value width) and the interlayer spacing (d002). This is because the electron on the surface of the graphene moves quantum mechanically and has electrical and magnetic properties that are different from those of existing materials. This phenomenon occurs because the electron collides with the external electric field and the applied electrons change the behavior. Can be explained. Also, since the surface electrons of the graphenes form a skeleton of the gap between the graphenes and have a large influence on the crystal structure, it can be seen from the present invention that the externally applied electric field greatly influences the crystal structure of the graphene. Especially, it is thought that AC is more unstable in DC than parallel but maintains parallel state in AC, but it is thought that parallel state changes in short time in AC atmosphere and it may be changed by electric frequency. These results show that applying a radio-type electric field can affect the crystal structure of graphene.

As a concrete example of the wireless type, the FWHM (half value width) change rate and the interlayer spacing (d002) change rate of the 5-layer graphene measured after continuously irradiating the electromagnetic waves of the MHz, GHz, and THz regions for 10 minutes were measured. The results are shown in Table 6.

The results in Table 6 are very important in that they confirm that graphene crystals do not change linearly with changes in the frequency of the electromagnetic waves. In addition, it was confirmed that the crystal structure of graphene changes most greatly in the GHz band, which is related to the electronic structure of graphene. However, moisture adsorbed between the graphene layers or on the surface, Group) interferes with the GHz electromagnetic wave to generate a large vibration. These results are obtained only through the present invention.

The uniaxial magnetic field at a distance of 0 cm is applied to the rate of change of the FWHM (half value width) and the interlayer spacing (d002) measured under the influence of a unipolar magnetic field of 0 cm in the distance of Table 3, Table 7 shows the FWHM (half value width) change rate and the interlayer spacing (d002) change rate measured at 150 ° C in a low temperature (liquid nitrogen) state.

This indicates that graphene crystals change dramatically when warming (500 ° C) or cooling (-150 ° C) is performed, but the degree of change in the case of no magnetic field and that of magnetic field are different.

An X-ray analyzer capable of applying electromagnetic force to a graphene specimen according to the present invention includes a specimen holder capable of gripping and stretching at least a pair of edges of a graphene specimen, It is also possible to perform X-ray analysis while being stretched in a unit of 0.1 Å or more (the schematic diagram can be seen from [FIG. 9] to [FIG. 11]). In actual measurement, the measurement conditions can be established by the elongation to the length of the graphene specimen (the ratio of the elongated length to the original length), and the number of benzene rings in the linear direction of graphene inflation in the future is evaluated, can do. In order to verify the present invention, the stretching was performed within the range of 0.1 to 30%.

As a specific concrete example, a CVD 5-layer graphene specimen transferred onto a PET film was placed on a metal plate, and a PET film protective film was placed on one side of the upper surface of the graphene specimen. Then, a metal plate was placed on the portion where the PET film protective film was placed, , And the results of measurement of FWHM (half value width) change rate and interlayer spacing (d002) change rate according to one side elongation by performing X-ray diffraction by stretching the relevant part (PET film and graphene specimen) are shown in Table 8 .

In addition, the same conditions as those of the FWHM (half value width) change rate and the interlayer spacing (d002) change rate measured in the 10% one side stretching state in Table 8 are applied in the same manner, but the unipolar magnetic field And the change rate of the FWHM (half-value width) measured by the method of the present invention and the rate of change of the interlayer spacing (d002) are shown in Table 9.

[Table 9] shows that graphene is stretched and the graphene crystal structure is significantly changed when a magnetic field is applied.

[Table 10] are the data that can confirm the effect of the present invention on the graphene powder. As described above, graphene powder prepared by chemically reducing graphene oxide produced by chemically oxidizing graphite was used. The grains produced by peeling the graphite are not easily fixed to the substrate like the thin graphene, so that the graphene powders are solidified by using a binder through which the X-rays are transmitted. Table 10 shows the results of the two-sided stretching under the unipolar magnetic field applied at a separation distance of 0 cm from Table 3 in which the specimen is placed in the x-ray holder (immobilized after coating on the x-ray holder).

The results in [Table 10] are small compared with the graphene thin film, but clearly show the crystal structure change of graphene due to magnetic field and elongation.

The above examples confirm that graphene crystallization studies can be performed under electromagnetic application. As described above, according to the present invention, it is possible to study the crystal structure of graphene by various electromagnetic waves by providing the electromagnetic XRD, and at the same time, it is possible to carry out the elongation, temperature control, pressure control, humidity control, It becomes possible to carry out crystal structure studies.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but is capable of various modifications and alterations without departing from the spirit and scope of the invention. Do. It is therefore intended that the appended claims cover such modifications and variations as fall within the true scope of the invention.

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Claims (21)

delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete A chamber in which the graphene specimen is placed;
An electromagnetic applicator for applying at least one of electricity and magnetism to the graphene specimen in the chamber;
An X-ray irradiating device for irradiating the graphene specimen in the chamber with X-rays; And
And an X-ray analyzer capable of applying electromagnetic force to the graphene specimen, wherein the X-ray analyzer is capable of applying electromagnetic force to the graphene specimen. As an X-ray analysis method for graphene having a very fine thickness used,
(a) preparing an X-ray analysis apparatus capable of applying electromagnetic force to the graphene specimen;
(b) laying a graphene specimen having 1 to 10 layers and a size of 0.3 x 0.3 cm or more in the chamber; And
(c) an X-ray irradiating device irradiates the graphene specimen with X-rays to detect X-rays transmitted or diffracted or reflected by the detecting device, wherein at least one of electricity and magnetism is applied to the graphene specimen The method comprising the steps of:
The X-ray irradiating angle and the arrangement of the detecting apparatus in the step (c) are set by the 2? (Theta) -ω (omega) method and the angle of the X-rays irradiated to the specimen is determined in the range Characterized in that the graphene layer has a thickness in the range of 0.1 to 10 microns.
[Investigation angle derivation expression]
X-ray irradiation angle = (2? _(Hkl) 2) 占 1 占
2 &thetas; (hkl): Diffraction angle of the peak center of the reference graphene crystal plane having a specific Miller index
A chamber in which the graphene specimen is placed;
An electromagnetic applicator for applying at least one of electricity and magnetism to the graphene specimen in the chamber;
An X-ray irradiating device for irradiating the graphene specimen in the chamber with X-rays; And
And an X-ray analyzer capable of applying electromagnetic force to the graphene specimen, wherein the X-ray analyzer is capable of applying electromagnetic force to the graphene specimen. As an X-ray analysis method for graphene having a very fine thickness used,
(a) preparing an X-ray analysis apparatus capable of applying electromagnetic force to the graphene specimen;
(b) laying a graphene specimen having 1 to 10 layers and a size of 0.3 x 0.3 cm or more in the chamber; And
(c) an X-ray irradiating device irradiates the graphene specimen with X-rays to detect X-rays transmitted or diffracted or reflected by the detecting device, wherein at least one of electricity and magnetism is applied to the graphene specimen The method comprising the steps of:
The X-ray irradiating angle and the arrangement of the detecting device in the step (c) are set in a 2? (Theta) -ω (omega) method, and the detecting device calculates an angle Characterized in that the graphene is installed within a range of from 0.1 to 10 microns.
[Detection angle derivation expression]
X-ray detection angle = (2? _(Hkl) ? 2) 占 1
2 &thetas; (hkl): Diffraction angle of the peak center of the reference graphene crystal plane having a specific Miller index

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