KR101580252B1 - Method of Healing Defective Graphene and the Defect-healing Graphene - Google Patents

Abstract

The present invention provides a method for healing structural defects of graphene. According to one embodiment of the present invention, graphene in which a defective area including a structural defect exists and a graphene containing a hetero element Contacting the precursor gas discontinuously and repeatedly to bond the heterogeneous material to the defect region.

Description

[0001] The present invention relates to graphene, and more particularly, to a method of healing graphene and a method of healing graphene,

The present invention relates to graphene defects and methods for healing defects, and more particularly to methods for healing structural defects of graphene and graphene having healed structural defects.

Graphene is a novel two-dimensional carbon material discovered in 2004, an ultra-thin structure consisting of a single carbon atom layer of hexagonal honeycomb structure. Graphene is one of the most outstanding materials in terms of strength, thermal conductivity and electron mobility, and is widely regarded as a key material that can be applied to various fields such as displays, rechargeable batteries, solar cells, light emitting devices and sensors.

Graphene is produced largely by mechanical stripping, chemical vapor deposition, epitaxial synthesis, or chemical stripping. During the manufacture and transport of graphene, point defects, dislocations, defects such as boundary, crack, fold, wrinkles or residue must be formed and these defects are known to deteriorate the properties of the graphene, in particular the electrical properties .

 Recently, studies have been conducted to heal defects of graphene. However, as in US Patent Publication No. 2013-0071616 or US Patent Publication No. 2013-0071564, a portion where a defect exists is covered with another graphene, To a material similar to graphene, and the like have been proposed and the like have been proposed and have been widely used as point defects, dislocations, grain boundaries, cracks, folds, wrinkles, There is almost no research on how to heal structural defects of graphene itself.

U.S. Published Patent Application No. 2013-0071616 U.S. Published Patent Application No. 2013-0071564

It is an object of the present invention to provide a method for healing structural defects of graphene and to provide a method for healing defects of graphene which heals the defects stably for a long period of time, The present invention provides a method for healing graphene which can be treated in a short time,

It is another object of the present invention to provide a graphene having healed structural defects, to provide graphene having excellent electrical and mechanical properties, and to provide graphene which is stably maintained for a long period of time.

The present invention provides a defect repair method of graphene that includes structural defects.

A method for repairing defects of graphene according to an embodiment of the present invention includes disposing a graphene having a defective region including structural defects and a precursor gas containing a heteroatom discontinuously and repeatedly, And bonding the heterogeneous substance to the defective region.

In the defect repair method of graphene according to an embodiment of the present invention, the discontinuous repetitive contact of the graphene and the precursor gas is performed by repeating at least the following steps i) to ii) as one cycle, . ≪ / RTI >

i) contact with the precursor gas,

ii) Purging by inert gas

In the defect repair method of graphene according to an embodiment of the present invention, the hetero element of the precursor gas may include one or more elements selected from a non-metal element and a metal group including oxygen, nitrogen and sulfur .

In the defect repair method of graphene according to an embodiment of the present invention, the discontinuous repetitive contact between the graphene and the precursor gas is performed by repeating at least the following steps i) to iv) as one cycle, . ≪ / RTI >

i) contact with the first precursor gas,

ii) purge by inert gas,

iii) contact with the second precursor gas,

iv) Purging by inert gas

In the defect repair method of graphene according to an embodiment of the present invention, the first precursor gas may contain one or more elements selected from oxygen, hydrogen, nitrogen and sulfur, and the second precursor gas may be a metal Element.

In the defect repair method of graphene according to an embodiment of the present invention, a structural defect is one of a point defect, a line defect, a crack, a fold, and a wrinkle. Or two or more selected defects.

In the defect repair method of graphene according to an embodiment of the present invention, the step of heat treating the graphene before the contact between the graphene and the precursor gas to remove organic substances present on the surface of the graphene .

In the defect repair method of graphene according to an embodiment of the present invention, the dissimilar material may include a metal or a metal compound.

In the defect repair method of graphene according to an embodiment of the present invention, the metal compound may be one or more selected from metal oxides, metal nitrides and metal sulfides.

In the defect repair method of graphene according to an embodiment of the present invention, the metal compound may be in a non-stoichiometric state.

In the defect repair method of graphene according to an embodiment of the present invention, the defective region of the graphene may be doped with p-type or n-type by the dissimilar material.

In the defect repair method of graphene according to an embodiment of the present invention, the repetitive contact between the graphene and the precursor gas may be 100 times or less.

The present invention includes defect repair graphene obtained by the defect repair method of graphenes described above.

The present invention provides a defect healing graphene wherein graphene structural defects are healed.

The defect repair graphene according to an embodiment of the present invention may include a graphene and a heterogeneous material selectively bonded to a defect region including a structural defect of the graphene.

In the defect repair graphene according to an embodiment of the present invention, the dissimilar material may be a metal or a metal compound.

In the defect repair graphene according to an embodiment of the present invention, the dissimilar material may be an atomic layer in which 2 to 100 atomic layers are stacked in the defect region, for each of the different elements constituting the dissimilar material.

In the defect repair graphene according to an embodiment of the present invention, the metal may be a metal selected from the group consisting of metals, metals, and transition metals.

In the defect repair graphene according to an embodiment of the present invention, the metal compound may be selected from one or more of metal oxide, metal nitride and metal sulfide groups.

In the defect repair graphene according to an embodiment of the present invention, the metal compound metal may be a metal selected from the group consisting of metals, metals, and transition metals.

In a defect repair graphene according to an embodiment of the present invention, the metal compound may be in a non-stoichiometric state.

In the defect repair graphene according to an embodiment of the present invention, the defect region of the graphene may be doped with p-type or n-type by the dissimilar material.

In a defect repair graphene according to an embodiment of the present invention, the dissimilar material may include a graphene in which a defective region including a structural defect exists, and a precursor gas containing a dissimilar element discontinuously It may be formed by repeated contact.

The present invention includes an element comprising the defect repair graphenes described above.

The method of healing graphene defects according to the present invention is a method of healing graphene defects by selectively interposing a dissimilar material to a defective area by discontinuous repeated contact of the graphene and precursor gases to thereby form a spot defect, a grain boundary, a dislocation, ) Of the graphene itself can be cured. In addition, since the structural defects of graphenes can be healed, the physical properties such as electrical and mechanical properties of graphene can be remarkably improved. In addition, since structural defects can be healed by a very simple method of discontinuous repetitive contact between graphene and precursor gas, it is advantageous that large area graphene can be treated in a short time. Further, since the dissimilar materials can be selectively bonded to the defective region by the discontinuous repeated contact of the graphene and the precursor gas, only the defective region can be selectively healed without damaging the characteristics of the graphene itself, The degree of healing of the defective area can be precisely controlled. Further, as the dissimilar material chemically bonded to the structural defects of graphene is formed by the discontinuous repetitive contact of the graphene and the precursor gas, the physical properties of the graphene improved by the defect healing can be stably maintained for a long time There are advantages.

Defect-healing graphenes according to the present invention can be used for graphene defects such as point defects, grain boundaries, dislocations, wrinkles, etc., inherent defects that must be present in graphene The structural defects themselves are healed, which has the advantage of having significantly improved electrical properties. Further, there is an advantage that the inherent characteristics of the graphene are not damaged as the defects are healed selectively only in the defective area in which the defects exist. In addition, since the heterogeneous material is chemically bonded to the structural defects of the graphene, the physical properties of the graphene improved by the defect healing can be stably maintained for a long time.

1 is a schematic sectional view based on AFM (atomic force microscopy) and AFM analysis results of defect repair graphene produced in the embodiment,
2 is a transmission electron microscope photograph of the defect repair graphene produced in the example,
3 is a diagram showing an elemental analysis result of the defect repair graphene produced in the embodiment,
FIG. 4 is a view showing the X-ray photoelectron spectroscopy (XPS) analysis result of the defect repair graphene produced in the embodiment,
5 is a graph showing the results of Raman analysis of defective healing grains produced in the example,
6 is a view showing a measurement of the surface resistance of the defect repair graphene manufactured in the embodiment,
7 is a view showing measurement of the water contact angle of the defect repair graphene produced in the embodiment,
8 is a graph showing a lateral force measurement result of the defect repair graphene manufactured in the embodiment,
9 is a graph showing the measurement of the surface resistance of graphene treated in the same manner as in the embodiment without removing the organic matter remaining on the graphene.

Hereinafter, a method of healing graphene defects according to the present invention will be described in detail. Hereinafter, the technical and scientific terms used herein will be understood by those skilled in the art without departing from the scope of the present invention. Descriptions of known functions and configurations that may be unnecessarily blurred are omitted.

The present invention provides a defect repair method of graphene that includes structural defects.

A method for repairing defects of graphene according to an embodiment of the present invention includes disposing a graphene having a defective region including structural defects and a precursor gas containing a heteroatom discontinuously and repeatedly, And bonding the heterogeneous substance to the defective region.

Since graphene has a hexagonal honeycomb structure in which each carbon atom is connected by a sp2 bond, the non-defective region of the graphene, that is, the region having an intact hexagonal honeycomb structure with carbon atoms, is extremely low in reactivity with the precursor gas . Thus, when the graphene contacts a precursor gas containing a different element, the defective region of the graphene can selectively react with the precursor gas. That is, when the graphene and the precursor gas containing the heteroatom are brought into contact with each other, the defective region of graphene may become the nucleation site of the dissimilar material.

Discontinuous repeated contact of the graphene with the precursor gas improves such defect selectivity and allows precise control of the degree of formation of the heterogeneous material formed in the defect region. The degree of formation of the heterogeneous material formed in the defect region affects the degree of defect healing due to the bond between the heterogeneous material and the defect region and the growth of the heterogeneous material nucleated in the defect region. The graphene and the precursor gas are discontinuously and repeatedly By the contact, the degree of formation of the heterogeneous material can be precisely controlled so that the structural defects of the graphene are healed, but the deterioration of the physical properties of the graphene can be prevented by the heterogeneous material.

As described above, the defect repairing method according to an embodiment of the present invention includes a step of discontinuously and repeatedly contacting the precursor gas, which is an elemental source of graphene and a dissimilar material, By bonding, it is possible to heal structural defects which are inherent defects of graphene. The heterogeneous material can be produced by reactive bonding between the precursor gas and the defective region of the graphene, which bond may be a chemical bond. In particular, the reactive bond between the precursor gas and the defective region may be a chemical bond between the heteroatom contained in the precursor gas and the carbon atom or heteroatom located in the structural defects of the graphene. Chemical bonds can include ionic bonds, covalent bonds, and / or van der Waals bonds. Thus, the heterogeneous material may be in a chemically bonded state, rather than a physical attachment to a defective region of graphene.

Graphene to be healed may be single-layer graphene or multi-layer graphene and may include graphene produced by mechanical stripping, chemical vapor deposition, epitaxial or chemical stripping. Further, the graphene which is a defect repair target may be in a laminated state stacked on a support for supporting graphene, or may be in a state obtained during the manufacturing step of a device provided with graphene. That is, the defect repair method of graphene provided in the present invention may be performed independently of the manufacture of the graphene after the manufacturing of the graphene, or may be performed as an intermediate step of the manufacturing process of the device using the graphene.

The structural defects of graphene may be inherent defects of graphene and the defects of graphene itself may be point defects, line defects, cracks, fold and / or wrinkles. The point defects of graphene include vacancy defects, carbon-interstitial defects, interstitial defects due to hetero elements, and / or substitutional defects due to hetero elements. And may include a pentagonal ring structure and / or a hexagonal ring structure structurally. The line defect of graphene may include dislocations, grain boundaries and / or other graphene edges that are partially located on the one graphene. As described above, in one embodiment according to the present invention, the defects to be cured may not contain the dissimilar materials (including the polymer) partially remaining on the graphene, as they are self-defects of the graphene. Further, as will be described later, in order to effectively and selectively heal the structural defects of graphene, it is preferable that the graphene and the precursor gas are in contact with each other after the partially remaining heterogeneous material on the graphene is first removed.

The precursor gas in contact with the graphene is a source of a material for supplying a hetero-element contained in a hetero-material formed in a defective region of graphene, and a source of a doping element doping graphene to n-type or p-type. . The precursor gas in contact with the graphene may chemically react with a defective region of the graphene, specifically, a structural defect of graphene, and a substance capable of forming a dissimilar material by such a reaction bond can be used.

In detail, the heterogeneous element of the precursor gas may be one or more elements selected from the group consisting of non-metals and metals. In detail, the non-metallic element may be one or more elements selected from oxygen, nitrogen and sulfur, and the metal element may be one or more elements selected from the group consisting of metals, metals and transition metals. The transition metal may be selected from the group consisting of scandium, yttrium, lanthanum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten The metal may include lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, cadmium, manganese, iron, ruthenium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, Calcium, strontium, and barium.

Precursor gases include precursor materials used as a source of nonmetal or metal elements in conventional chemical vapor deposition (CVD) or atomic layer deposition (ALD).

In the case where the precursor gas contains a nonmetal element as a hetero-element contained in a hetero-material in which a deficient region is formed, examples of specific precursor gases include H ₂ O, H ₂ O ₂ , O ₃ , NO ₂ , N ₂ O ₄ , H ₂ S or S, but is not limited thereto.

In the case where the precursor gas contains a metallic element as a hetero-element contained in a hetero-material formed in a defective region, the precursor gas may be an organic metal compound or a metal halide. As described above, any organometallic compound or metal halide conventionally used as a material supply source for the CVD or ALD process can be used. As the precursor gas, for example, AlCl ₃ , AlBr ₃ or AlMe ₃ (Me = methyl ). However, it should be understood that the present invention can not be limited by the kind of precursor gas used as the source of the metal element, and more detailed materials of usable precursor gas are described in Puurunen et al., JOURNAL OF APPLIED PHYSICS 97, 121301, 2005).

The dissimilar material formed on the defective region of graphene by discontinuous repetitive contact with the precursor gas may be a metal or a metal compound, and the metal compound may be one or more selected from metal oxides, metal nitrides and metal sulfides .

The discontinuous repetitive contact of the graphene with the precursor gas may comprise at least the following steps i) to ii) as one cycle, wherein the cycle is repeatedly performed.

i) contact with the precursor gas,

ii) Purging by inert gas

When the precursor gas and the graphene are repeatedly contacted repeatedly by repeating the steps i) to ii), it is possible to selectively heal the graphene defective area, do not affect the defective graphene area, The degree of reaction with the precursor gas can be precisely controlled so that it can heal.

Upon contact of the graphene with the precursor gas (step i), a self-limiting reaction can form a single layer containing a hetero-element on the surface of the defect region of the graphene, Upon purging (step ii) unreacted precursor gas (and byproducts) can be removed.

By repeating at least i) to ii) steps, a heterogeneous material containing a heterogeneous element contained in the precursor gas can be formed in the defective region. When the heterogeneous substance is made of a single element such as a metal, it is needless to say that after the step ii), a step of activating the surface of the single layer containing the heterogeneous element formed by the step i) . The surface activation is a step in which a single layer containing a heteroatom is reacted with i) the precursor gas of the step so that one layer containing the heteroatom can again be bonded onto the previously formed single layer, and the atomic layer deposition (ALD; Atomic Layer Deposition) can be used. In a specific, non-limiting example, activation may be by thermal activation.

The cycle including at least i) to ii) step may be repeated 100 times or less, specifically 2 to 100 times, preferably 2 to 30 times, whereby the surface of the normal graphene region beyond the defect region is heterogeneous It can be prevented from being covered by the material.

(i) the amount of precursor gas supplied, the contact time between the precursor gas and the graphene, and the purging time at the purging step (ii) may be the conditions conventionally used in the atomic layer deposition method. In a specific, non-limiting example, i) the precursor gas is supplied to a chamber in which the first precursor gas of 1 to 1000 sccm is located for 1 msec to 10 sec, and the first precursor gas For 1 sec to 100 sec, and ii) the step can be performed. The purging step ii) The gas used in the step is irrelevant to the inert element, and the inert gas of 1 to 1000 sccm is continuously supplied to and discharged from the chamber for 1 sec to 100 sec, and purging can be performed. It is of course also possible that the pressure of the chamber in i) step or ii) step can be adjusted and maintained in a mtorr order.

Preferably, the precursor gas may be two or more gases (including the first precursor gas and the second precursor gas) that are different from each other, and the heterogeneous material bound to the defect region may include at least a first heterogeneous element contained in the first precursor gas And a second heterogeneous element contained in the second precursor gas. The hetero compound may be a metal compound, and the metal compound may be one or more selected from metal oxides, metal nitrides and metal sulfides. If the heterogeneous material is a heterogeneous compound, preferably a metal compound, the structural defects of the graphene can be healed more stably, the heterogeneous material can stably cover the structural defective region of the graphene, and the defect healing effect can be extremely And can be stably maintained.

In accordance with an embodiment of the present invention, there is provided a method of producing a precursor gas comprising the steps of: i) contacting with a first precursor gas, ii) purging step with an inert gas, iii) (Including the first precursor gas and the second precursor gas) and graphene by repeating the cycle of one cycle including the step of contacting the precursor gas with the precursor gas and the step of purging with the inert gas . In this case, it is possible to selectively form a heterogeneous material in the defect region more effectively, to stably heal the structural defect, to prevent the defective graphene region from affecting the precursor gas The degree of reaction can be precisely controlled.

The first precursor gas may be a source of a material that supplies the first heteroatom contained in the dissimilar compound and at the same time may be a source of a doping element that dopes the graphene n-type or p-type.

The second precursor gas may be a source of a material that supplies the second heteroatom contained in the dissimilar compound and at the same time may be a source of the doping element doping the graphene n-type or p-type.

In one embodiment of the present invention, the first heterogeneous element contained in the first precursor gas may be a non-metallic element, and more specifically, the first precursor gas may be a first heterogeneous species selected from oxygen, nitrogen and sulfur, Element. Examples of specific, non-limiting first precursor gases include H ₂ O, H ₂ O ₂ , O ₃ , NO ₂ , N ₂ O ₄ , H ₂ S or S, and the like. Preferably, the first precursor gas may contain oxygen as a first heteroatom. Oxygen can bond very stably with the dangling bonds present in the defective region of the graphene and can also combine with the folds and / or wrinkles of the graphene, There are advantages that can be combined with structural defects. Further, since the first precursor gas contains oxygen as the first hetero atom, the reactivity with the second precursor gas can be ensured even at a low temperature, and the stability of the defect healing can be improved.

Examples of the oxygen-containing first precursor gas include H ₂ O, H ₂ O _2, O ₃ , and the like. Preferably, the first precursor gas containing oxygen is water vapor. As is known, the surface of graphene is hydrophobic. Thus, by using water vapor as the first precursor gas, it is possible to effectively prevent unwanted reaction of the first precursor gas with the normal region in which no defect exists, and the first precursor gas can react more selectively with the defective region have. In addition, since water vapor is composed of only one oxygen and two hydrogen atoms, it is possible to effectively bond even when the density of structural defects in a defective region is high. That is, when the first precursor gas has a large molecular size, the first precursor gas already bound to the defect may be constrained to the bonding of the first precursor gas with a defect located adjacent to the first precursor gas. However, in the case of water vapor, high-density defects such as dislocation can also be cured, as the state associated with the defect is the hydroxyl group (-OH). Further, due to the high reactivity of the hydroxyl groups, it is possible to effectively react with various second precursor gases at low temperatures.

The second precursor gas may be a gas capable of reacting with an element contained in the first precursor gas to form a compound with an element contained in the first precursor gas while at the same time doping the graphene into n-type or p- It can be the source of the element. In detail, the second precursor gas may be a gas capable of forming a dissimilar compound by chemically bonding with the first precursor gas chemically bonded to the structural defect, and at the same time, Type doping element.

In one embodiment of the present invention, the second precursor gas may comprise a second heteroatom metal element. The metal element may be one or more elements selected from the group consisting of metals, metals and transition metals. The transition metal may be selected from the group consisting of scandium, yttrium, lanthanum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten The metal may include lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, cadmium, manganese, iron, ruthenium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, Calcium, strontium, and barium.

The second precursor gas may be an organometallic compound or a metal halide, and as described above, any organometallic compound or metal halide conventionally used as a material source for CVD or ALD processes may be used. Examples of the precursor gas include AlCl ₃ , AlBr ₃ , and AlMe ₃ (Me = methyl).

By sequentially repeating the cycle including steps i) to iv), a first precursor gas containing a non-metal element selected from oxygen, nitrogen and sulfur and a second precursor gas containing a metal element By repeated contact, a metal compound selected from one or more of metal oxides, metal nitrides and metal sulfides can be chemically bonded to the defective region of graphene in the defective region of graphene.

In order to heal structural defects of graphene, a first precursor gas containing a non-metallic element is used to selectively bind a non-metallic element to structural defects existing in graphene, and then a second precursor gas, preferably a metal element By using the second precursor gas containing a metal compound to form a metal compound on the defective region, deterioration of electrical and physical properties due to defects can be more effectively healed.

The metal compound formed in the defective region of graphene may be preferably a metal oxide, and the metal oxide is bonded to the defective region, so that the physical properties of the defective graphene grains can be stably maintained for a long period of time.

When the first precursor gas and the second precursor gas are in alternate contact with the graphene, the temperature of the graphene may be such that the reaction between the precursor gas (the first precursor gas and the second precursor gas) and the graphene occurs smoothly, To several hundred degrees Celsius. In a specific example, upon contact with the precursor gas, the graphene may be heated to an extremely low temperature, such as 70-130 ° C, and this low temperature may be achieved even when graphene is provided on an organo- It is possible to prevent components other than graphene from being damaged by heat when healing structural defects, to improve productivity, and to reduce the cost of healing defects.

The metal compound formed in the defect region may be in a non-stoichiometric state, and the metal compound in this non-stoichiometric state is more effective for healing defects in particular. In a non-stoichiometric state, the metal compound may be, according to one embodiment of the present invention, i) contact step with a first precursor gas, ii) purging step with an inert gas, iii) contact step with a second precursor gas, and iv) A step including a purging step with an inert gas may be formed as one cycle, and the degree of repetition of the cycle may be adjusted.

In detail, as the cycle is repeatedly performed, the structural defects of graphene are grown in the plane direction and the thickness direction of the graphene of the metal compound produced as a nucleation site. The coverage of the surface of the fin can be controlled and a non-stoichiometric state metal compound can be formed on the defect region. In the non-stoichiometric state, metal compounds that are stacked by cyclic repetition can all contribute to the healing of structural defects of graphene, so that the defects can heal effectively, but the physical properties of graphene itself So that it is preferable. To form the metal compound in the non-stoichiometric state, the cycle comprising steps i) through iv) may be repeated no more than 100 times, preferably 2 to 30 cycles, more preferably 2 to 10 times more Preferably 6 to 8 times.

Wherein the metal compound in the non-stoichiometric state is a real number having a valence of M _x N _y (0 <x <N, a valence of 0 <y <M, M is a metal element originating from the second precursor gas, 1 < / RTI &gt; precursor gas). As an example of the case where M is aluminum, the non-stoichiometric metal oxide may be represented by Al _x O _y (0 <x <2, 0 <y <3). When a non-stoichiometric metal compound is formed in the defect region, the defect region of the graphene can be doped with n-type or p-type, and the sheet resistance of the graphene before defects %, And the long-term stability can be maintained.

In addition, the cycle which is repeated 100 times or less, preferably 2 to 30 times, more preferably 2 to 10 times, still more preferably 6 to 8 times prevents the metal compound from being formed to a defect-free normal graphene region . If a metal compound is formed to a normal graphene region, the physical properties of the graphene itself may be impaired. If the number of repetition cycles is too small, there is a risk that the degree of defect healing caused by the metal compound is insignificant or that the defect healing effect can not be stably maintained for a long time.

(ii) a purging time at a purging step (ii, iv); and (iii) at a step, a supply amount of the second precursor gas, a second precursor gas And the contact time of graphene may be the conditions conventionally used in the atomic layer deposition method.

In a specific, non-limiting example, i) the first precursor gas is supplied to a chamber in which graphene is located for 1 msec to 10 sec of a first precursor gas at 1 to 1000 sccm, After exposure to the precursor gas for 1 sec to 100 sec, ii) step can be performed. iii) In step, the second precursor gas is supplied to the chamber in which the grains are positioned for 1 msec to 50 sec of the first precursor gas at 1 to 1000 sccm, and exposed to the first precursor gas to which the graphene is supplied for 1 sec to 100 sec , Iv) step can be performed. The purge step ii) The gas used in the step i) and the iv) step is irrelevant to the inert element, and the inert gas of 1 to 1000 sccm is continuously supplied to and discharged from the chamber for 1 sec to 100 sec, and purging can be performed. It is of course also possible that the pressure of the chamber in i) step or iii) step can be adjusted and maintained in the mtorr order.

In the method according to an embodiment of the present invention, as a specific example of the step of discontinuously and repeatedly contacting the precursor gas with the graphene in which a defective region including a structural defect exists, &Lt; / RTI &gt;

That is, the method according to an embodiment of the present invention includes a step of discontinuously and repeatedly contacting a precursor gas with a graphene in which a defective region including a structural defect exists using an atomic layer deposition method .

When using two or more kinds of precursor gases different from each other, the method according to an embodiment of the present invention uses a graphene having a defective region including a structural defect by using an atomic layer deposition method, And discontinuously bringing the precursor gas and the second precursor gas into an alternating contact.

From a material point of view, a method according to one embodiment of the present invention will now be described in which a method according to an embodiment of the present invention comprises contacting a precursor gas with a graphene in the presence of a defective region, To form a metal or metal compound selectively in the defect region.

In the method according to an embodiment of the present invention, the graphene is heat-treated before contacting the graphene with the precursor gas (including the first precursor gas and the second precursor gas) to remove the organic substances present on the surface of the graphene More steps can be performed.

Precursor gases, especially precursor gases containing non-metallic elements, also react with organic materials present on the surface of graphene and are prone to bond. Thus, if organic matter remains on the surface of graphene, there is a high possibility that the organic defect will be formed rather than the structural defects of the graphene, and that the structural defects of the graphene are not exposed to the surface due to the organic matter . As a result, the graphene is heat-treated to remove residual organic substances (including residual polymer) present in the graphene, and then contact with the precursor gas, preferably an alternate contact of the first precursor gas and the second precursor gas It is good.

The heat treatment for decomposition of the organic material may be performed at 300 to 600 ° C for 30 minutes to 2 hours, and the heat treatment may be performed in an atmosphere in which the inert gas flows. The flow of the inert gas is not particularly limited, but it may have a flow rate of 300 to 800 sccm.

The present invention includes defect repair graphene obtained by the defect repair method of graphenes described above.

The present invention provides defect healing grains wherein the defect is healed graphene.

The defect repair graphene according to an embodiment of the present invention includes graphene; And a heterogeneous material selectively bonded to a defect region including a structural defect of graphene.

Structural defects of graphene include point defects, line defects, cracks, folds, wrinkles, or partial lamination of other unwanted graphene layers, where the heterogeneous material is located at the location where each structural defect is located Lt; RTI ID = 0.0 &gt; and / or &lt; / RTI &gt; That is, if the structural defect is a surface defect, the heterogeneous material may be in the form of a plate covering the point defect, and if the structural defect is a line defect, the different material may be in the form of a band covering the line defect. Similar to the above, the heterogeneous material has a shape corresponding to the structural defects of the graphene, and may be in a form to cover the structural defects of the graphene.

The heterogeneous material selectively bound to the defect region may be a metal or a metal compound, and the heterogeneous material is chemically bonded to the structural defects of the graphene, whereby the defect is healed and the defective region of the graphene is p Type or n-type.

The metal of the metal or metal compound may be one or more selected from the group consisting of metals, metals and transition metals. The transition metal may be selected from the group consisting of scandium, yttrium, lanthanum, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten The metal may include lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, cadmium, manganese, iron, ruthenium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, Calcium, strontium, and barium.

The metal compound may be one or more selected from metal oxides, metal nitrides and metal sulfides. The heterogeneous material may preferably be a metal compound, more preferably a metal oxide, through which structural defects of graphene can be healed more firmly, a structural defective area of graphene can be stably covered by the heterogeneous material, The defect healing effect can be kept extremely stable for a long time.

The heterogeneous material may be an atomic layer of 2 to 100 layers laminated to each other by hetero atoms constituting a heterogeneous material in the defective region, preferably 2 to 30 layers, more preferably 2 to 10 layers , More preferably 6 to 8 layers of atomic layers may be laminated.

In detail, when the hetero-material is composed of a single element such as a metal, the hetero-material may be a stack of 2 to 100 layers of metal atoms. When the heterogeneous material is composed of two or more kinds of elements including a first heterojunction and a second heterojunction, such as a metal compound, the atomic layer of the first heterojunction and the atomic layer of the second heterojunction are alternately stacked, The atomic layer of one hetero atom and the atomic layer of the second hetero atom may be stacked in 2 to 100 layers. At this time, in order to clarify the technical meaning, the expression of a layer of atomic layer is used, and this layer can be interpreted as a layer partially formed in the structural defective region and is limited to a layer covering all of the exposed surface of graphene Of course not.

In the case where atomic layers of 2 to 100 layers, preferably 2 to 30 layers, more preferably 2 to 10 sides, and more preferably 6 to 8 layers are laminated to each other in the defect region for each of the different kinds of heteroatoms , It is possible to effectively cure structural defects of graphene while preventing degradation of the physical properties of graphene due to the dissimilar materials themselves.

When the heterogeneous material is a metal compound, it is preferable that the heterogeneous material has an atomic layer of 2 to 100 layers, preferably 2 to 30 layers, more preferably 2 to 10 sides, and more preferably 6 to 8 layers, When laminated, the metal compound may be in a non-stoichiometric state. The non-stoichiometric metal compound can greatly dope the defect region of graphene to n-type or p-type and maintain the long-term stability of the doping based on the sheet resistance of the graphene before healing the defect .

In detail, the doping by the metal compound can be discussed based on the Raman spectrum of graphene. In one embodiment of the present invention, the short wavelength shift of the G band and the 2D band on the basis of the Raman spectrum of the pre- a blue shift can be achieved. G-band and the movement of the 2D band is yes as a measure of how well the doping of the pins, around the defect healing is yes peaks positioned at 1598cm ^-1 and 2698cm ^-1, based on the pin. By forming a non-stoichiometric metal compound in the defect region, it is possible to further increase the blue shift or the long wavelength shift of the G band and the 2D band, and the general chemical doping The doping stability for a long time can be secured.

As a manufacturing method, the heterogeneous material to be formed in the defective region may be formed by repeating one cycle including the i) to ii) steps or the i) to iv) steps described above, A heterogeneous material may be formed at the nucleation site of the structural defects of graphene, so that a heterogeneous material may be selectively formed in the defective region and a heterogeneous material may be formed in a chemically bonded state with structural defects.

The present invention includes an element comprising the defect repair graphenes described above. An element including defect repair graphene may be any element containing graphene as its constituent element. For example, a graphene-containing device is a device in which graphene is a conductive material, an element provided in an electrode or wiring of the device, an element in which graphene is a semiconductor material, a device provided in a photoactive region or a channel region, And an electrooptical detection element provided as a sensing material. Specifically, the graphene-containing device may include an optical device, an electric device, a solar cell, or a detecting device, the optical device may include a light emitting device, the electric device may include a transistor, Or a gas detection sensor.

Hereinafter, embodiments of producing graphene using a chemical synthesis method, transferring the produced graphene to a silica substrate, and healing defects of graphene using an atomic layer deposition method are provided. It should be understood that the present invention can not be construed as limited by the embodiments.

(Production example)

Preparation of graphene by chemical synthesis

A 25 μm thick copper foil (Alfa-Aecer; 99.8%, No. 13382) was charged into a 2 inch diameter quartz tube and the pressure in the tube was adjusted to 600 mTorr, after which 50 sccm of argon and 20 sccm of hydrogen gas Lt; RTI ID = 0.0 &gt; 1000 C. &lt; / RTI &gt; A mixed gas of 30 sccm of methane (CH ₄ ) and 20 sccm of hydrogen was injected into the tube heated to 1000 ° C for 20 minutes, and the tube was cooled to obtain graphene.

  After the copper foil graphene was cut to 2 x 2 cm, polymethyl methacrylate (PMMA; Microchem, Inc. 950 A4) solution was spin-coated on the graphene (2500 rpm, 30 seconds) and dried at 80 ° C for 2 minutes To prepare a PMMA sacrificial layer.

Of the graphenes formed on both surfaces of the copper foil, the graphene on one side of which no PMMA sacrificial layer was formed was removed by using oxygen plasma, and the graphene-removed copper foil-graphene-PMMA sacrificial layer The laminate was floated in a 0.1 M molar ammonium persulfate solution ((NH ₄ ) ₂ S ₂ O ₈ ) for 8 hours to remove the copper foil.

The graphene-PMMA sacrificial layer from which the copper foil had been removed was washed with deionized water, and then laminated so that the SiO ₂ surface and the graphene were in contact with each other on the Si substrate on which the SiO ₂ was formed with a thickness of 300 nm by surface treatment with oxygen plasma. After drying for 2 hours in air, the graphene was bonded to the substrate at 110 ° C for 1 hour, and then immersed in acetone at 60 ° C to remove the PMMA sacrificial layer. Then, in order to remove the polymer (PMMA) residue remaining on the graphene, the graphene transferred to the substrate was heat-treated at 350 DEG C for 1 hour in an atmosphere of 500 sccm argon.

(Example)

The graphene (graphene-substrate laminate from which the polymer residue was removed) prepared in Production Example was charged into an atomic layer deposition chamber (S200, Savannah), and was heated at a temperature of 100 占 폚 and a flow rate of 30 Min. Thereafter, atomic layer deposition was performed using TMA (trimethylaluminum, Al (CH ₃ ) ₃ , Aldrich, 99.99%) and H ₂ O as a precursor gas to prepare defect repair graphene.

In detail, the atomic layer deposition was repeated one to 100 cycles, with H ₂ O (gas) pulse-first purging-TMA pulse-second purging as one cycle. The detailed cycle conditions are as follows. The H ₂ O pulse was supplied to the graphene for 20 seconds after the supply of 20 sccm of H ₂ O (g) for 0.1 second and the first purging was performed by supplying 20 sccm of nitrogen for 20 seconds. The TMA pulse was supplied to TMA (g) at 20 sccm for 0.015 seconds, then exposed to graphene for 20 seconds, and the second purging was performed by supplying 20 sccm of nitrogen for 30 seconds.

The electrical properties of the defect repair graphene fabricated in the examples were measured by measuring the surface resistance using a four-point probe system (CM-100, AiT) The resistance was measured.

The water contact angle of the defect repair graphene prepared in the examples was measured using a contact angle measuring apparatus (DSA 100, Kruss ^® ), and 3 μl of water droplets were dropped on at least six regions of the defect repair graphene.

X-ray photoelectron spectroscopy (XPS) analysis of the defect repair graphene prepared in the examples was performed using Al K? X-ray ((Multilab 2000, Thermo), and the spot size was 0.5 μm ² .

The Raman analysis of the defect-healing graphenes prepared in the examples was performed using a Raman analyzer (InVia Raman microscope, Renishaw), using a 514 nm laser, and the laser power density was 100 μW / μm ² or less.

Atomic force microscopy (AFM) analysis of defective healing grains produced in the examples was performed in a contact mode or a noncontact mode, and a force of 5 nN was applied to the AFM tips. The scan speed was 0.5 Hz, the scan area was 5 x 5 m, and the resolution was 256 x 256 pixels.

FIG. 1 is an atomic force microscopy (AFM) image showing the surface of the graphene before and after the atomic layer deposition, and a schematic cross-sectional view based on the height profile and the AFM analysis result corresponding to the portion indicated by the blue dotted line in the AFM image. 1 (a) and 1 (d) show the result of observing the surface of graphene (hereinafter referred to as bare graphene) before atomic layer deposition and the corresponding schematic diagrams, and Figs. 1 1 (c) and 1 (f) show the result of observing the graphene surface obtained by repeating the cycle 10 times in the atomic layer deposition in the embodiment and the corresponding schematic diagram, and 1 (c) and 1 And repeated observation of the graphene surface.

As can be seen in FIG. 1, a large number of wrinkles having a height of about 2 nm are present in the bare graphenes. When performing a cycle of 10 times, a defect region including a one- It can be seen that the compound is nucleated. In FIG. 1, island compounds in island form can be interpreted as nucleation sites, which are point defects which are zero-dimensional defects existing in graphene. It can be confirmed that both the one-dimensional defect and the zero-dimensional defect are nucleated and grown at almost the same rate, and that the heterogeneous compound is selectively formed in the defect region irrespective of the type and size of the defect. In the case of a sample in which the cycle was repeated 100 times, it can be seen that the heterogeneous compound covers almost the entire surface of the graphene in the form of a discontinuous film having pinholes.

FIG. 2 shows an HR-TEM image (FIG. 3 (a)) of the sample in which the cycle was repeated four times in the embodiment, FIG. 2 (b) FIG. 2 (c) is an electron diffraction pattern at the lower portion shown in yellow in FIG. 2 (a), and FIG. 2 (d) is an electron diffraction pattern at the entire region in FIG.

It can be seen from FIGS. 2 (b) to 2 (d) that the graphene region of FIG. 2 (a) consists of three grains in total, It can be seen that the graphene layer is located. The yellow line shown in FIG. 2 (a) shows the grain boundary between the upper two graphene layers analyzed based on the result of the electron diffraction pattern analysis. It can be seen from FIG. 2 (a) to FIG. 2 (d) that the heterogeneous compound is selectively formed in the region where the grain boundary of graphene exists.

3 (a) is a transmission electron microscope dark field image of a sample in which the cycle is repeated four times in the embodiment, and Fig. 3 (b) is a TEM-EDX of the region shown in Fig. And the result of mapping the Al element is shown. As can be seen from FIG. 3, it can be seen that Al is not detected as a whole on the entire surface of the graphene but only in a specific region where the defect is located.

FIG. 4 is a graph showing X-ray photoelectron spectroscopy (XPS) analysis results of a sample in which the cycle was repeated 0 times, 2 times, 4 times, 6 times, 8 times, 10 times or 100 times, ) Shows an Al 2p peak, and Fig. 4 (b) shows a C1s peak. In the figure, 0c, 2c, 4c, 6c, 8c, 10c and 100c mean that the cycle is the result of the samples which were repeated 0 times, 2 times, 4 times, 6 times, 8 times, 10 times and 100 times. As can be seen from FIG. 4, it can be confirmed that Al is detected even by repeating only two cycles. The C 1s peak located at 284.6 eV is due to the SP ² bond of the carbon in the graphene, and a peak is detected at the same position almost irrespective of the number of cycle repetitions. In the case of Al, the position of the Al 2p peak of the metal aluminum is 74 eV, and the position of the Al 2p peak of Al ₂ O ₃ is 76 eV. As can be seen in FIG. 4 (a), it can be seen that the peak of Al 2p is located between the metallic aluminum state (74 eV) and the aluminum oxide state (76 eV) of the stoichiometric ratio. It can be confirmed that it moves toward the oxide state. The low binding energy of Al is a typical result due to oxygen deficiency, which shows that AlxOy is formed in a non-stoichiometric state.

FIG. 5 is a graph showing a result of Raman analysis of the sample prepared in the embodiment, and FIG. 5 (a) is a diagram showing a Raman spectrum according to the number of times of cycle repetition. In FIG. 5 (a), 0c, 2c, 4c, 6c, 8c, 10c, 20c and 100c show the case where the cycle is 0, 2, 4, 6, 8, 10, Which is the result of repeatedly performed samples. 5 (b) is a diagram showing the correlation between the G band and the 2D band, with the position of the G band in the Raman spectra of FIG. 5 (a) as the x axis and the position of the 2D band as the y axis. In the case of bare graphene, it is found that graphene has a unique Raman spectrum as moisture and residual impurities (organic matter) are removed through heat treatment before atomic layer deposition. As the atomic layer deposition is performed and the nonstoichiometric ratio of AlxOy is formed in the defect region, the blue shift of the G band and the 2D band can be confirmed. It is known that the 2D band is mainly due to charge transfer, and that the short wavelength shift is caused by hole doping and the long wavelength shift (red shift) is caused by electron doping. 5, it can be seen that p-type doping of graphene occurs even when the cycle is repeated twice. In the case of repeating 8 times, the G band is increased up to 1603 cm ^-1 and the 2D band is increased up to 2707 cm ^-1 It can be confirmed that the short wavelength is moved.

FIG. 6 is a graph showing the surface resistance of the defect repair graphene fabricated in the embodiment and showing the surface resistance of the graphenes according to the repetition frequency of the cycle. FIG. In FIG. 6, the x axis is the number of repetitions of the cycle performed in the embodiment, and the y axis is the number of times corresponding to the x axis, and the cycle is repeated so that the surface resistance of the graphene on which the atomic layer deposition has been performed is performed before the atomic layer deposition And the surface resistance of the pin (bare graphene).

As can be seen from FIG. 6, the surface resistance of the graphene decreases even after performing the cycle of only two cycles. As the bare graphene is the organic residue removed by the heat treatment, the surface resistance of the graphene decreases Is due to the healing of structural defects of graphene. It can be seen that both the samples subjected to the cycle of 2 to 30 cycles repeatedly had a lower surface resistance than that of the bare graphenes and furthermore, a remarkable reduction of the surface resistance of 15% occurred in 6 and 8 cycles Able to know. It can be seen that when the aluminum oxide is covered with the majority of the surface of the graphene and acts as an insulating layer, the surface resistance is increased during the repeated 100 cycles. In this case, the surface resistance ratio (defect resistance / graphene sheet resistance / bare graphene sheet resistance) of FIG. 6 is determined by the sheet resistance measurement itself of the graphene according to the sheet resistance before / A sheet resistance higher than the surface resistance of graphene can be measured. In view of this, it can be predicted that the surface resistance of the graphene healing the defect through the embodiment will have a lower value than the measured value.

FIG. 7 is a view showing the measurement of the water contact angle of the defect repair graphene manufactured in the embodiment, and is a view showing the water contact angle of the graphenes according to the number of repetition of the cycle. As can be seen from FIG. 7, bare graphene (A in FIG. 7) has a water contact angle of 84.7 °, indicating water repellency. On the other hand, in the case of the sample (D in FIG. 7) in which 100 repetitions were performed, the contact angle of the aluminum oxide was about 19 °, which is the normal water contact angle, It can be seen that it is covered. On the other hand, when the aluminum oxide having a nonstoichiometric ratio is selectively formed in the defect region, that is, when the cycle is repeatedly performed 2 to 30 times, it is confirmed that the water contact angle is higher than that of bare graphene. It can be seen that the increase in the water contact angle is also greater for samples in which the cycle is repeated 2 to 10 times, where a large decrease in sheet resistance occurs, and a significant reduction in sheet resistance of up to 15% For repeated samples, the increase in the water contact angle is known to be 10 °.

FIG. 8 is a graph showing a lateral force measurement result of a sample in which ten cycles were repeated in the embodiment, and is a result of using the contact mode AFM. Fig. 8 (a) is an AFM image of a sample in which 10 cycles are repeated, Fig. 8 (b) is a lateral force image of the area shown in Fig. 8 (a) In the area indicated by the actual vertical line in FIG. As can be seen from FIG. 8, it can be seen that the defective region to which the non-stoichiometric AlxOy is bonded has a larger frictional force than the surface of the graphene itself, and thus the non-stoichiometric AlxOy and the graphene are very solid It can be confirmed that they are combined.

The surface resistance was measured immediately after the defect healing, and after standing for one month at room temperature and normal pressure, the surface resistance was again measured to test the stability of the defect-healed graphene. In the case of the sample in which the cycle of 2 to 30 cycles was repeated, it was confirmed that the change in the sheet resistance was within 10% ((surface resistance immediately after the month after the defect) / surface resistance immediately after the defect healing * 100) It was confirmed that the change of the sheet resistance within the range of 5% was almost the same for the repeated samples. Furthermore, it was confirmed that the change of the sheet resistance was hardly occurred even at 10 months after the sample in which the cycle of 2 to 10 cycles was repeated.

9 is a graph showing the ratio of the surface resistance of graphene to the graphene according to the number of times of cyclic repetition when the cycle is repeated with respect to graphene which is not heat-treated at 350 DEG C for 1 hour in an argon atmosphere Fig. As can be seen from FIG. 9, when an organic matter remains on the surface of the graphene, a hydroxyl group binds to the organic material and an undesirable aluminum oxide layer is formed in the organic material. As a result, it can be seen that the sheet resistance of the graphene is rather increased as the nonconductive aluminum oxide is unnecessarily formed on the surface of the graphene. Thus, it is preferable to remove the organic residues present in the graphene first, and selectively bond the heterogeneous material to the defective region of the graphene, in order to heal structural defects of the graphene itself.

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 embodiments, but, on the contrary, Those skilled in the art will recognize that many modifications and variations are possible in light of the above teachings.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

Claims (18)

The precursor gas containing a hetero element and graphen having a defective area including at least one structural defect selected from point defects, line defects, cracks, folds, and wrinkles on the surface are discontinuously and repeatedly contacted to the defective area A defect repair method of graphene comprising the step of bonding a heterogeneous material,
Wherein the discontinuous repetitive contact of the graphene and the precursor gas is repeated by repeating the following steps i) to iv).
i) introducing a first precursor gas containing at least one heteroatom selected from oxygen, hydrogen, nitrogen and sulfur into the chamber and then for 1 to 100 seconds,
ii) an inert gas purging step,
iii) exposing the chamber to a second precursor gas comprising a second heterogeneous elemental metal for 1 second to 100 seconds,
iv) inert gas purge step delete delete delete delete delete The method according to claim 1,
Before contacting the graphene with the precursor gas,
And heat treating the graphene to remove organic matter present on the surface of the graphene. The method according to claim 1,
Wherein the dissimilar material is a metal or a metal compound. 9. The method of claim 8,
Wherein the metal compound is selected from the group consisting of metal oxides, metal nitrides and metal sulfides. 9. The method of claim 8,
Wherein the metal compound is in a non-stoichiometric state. The method according to claim 1,
Wherein the defective region of graphene is doped p-type or n-type by the dissimilar material. The method according to claim 1,
Wherein the repetitive contact is less than 100 times. A defect-healing graphene obtained by a defect repair method according to any one of claims 1 or 7 to 12. delete delete delete delete An element comprising defect repair graphene of claim 13.

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