Graphene structure and method of fabricating the same

A graphene structure and a method of forming the same may include a graphene formed in a three-dimensional (3D) shape, e.g., a column shape, a stacking structure, and a three-dimensionally connected structure. The graphene structure can be formed by using Ge.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 10-2010-0124233, filed on Dec. 7, 2010, in the Korean Intellectual Property Office (KIPO), the entire contents of which are incorporated herein by reference.

BACKGROUND

Example embodiments relate to a graphene structure and a method of fabricating the same, and more particularly, to a graphene structure having various structures and methods of fabricating the same.

2. Description of the Related Art

Graphene is a two-dimensional (2D) thin film having a honey-comb structure formed of one-atom-layer carbon. Carbon atoms form a carbon hexagonal plane having a 2D-bond structure with a sp2-hybrid orbital, and a composite of carbon atoms having the planar structure is referred to as graphene.

There are various methods of forming graphene including a mechanical exfoliation method, a chemical exfoliation method, a SiC thermal treatment method, a chemical vapor deposition (CVD) method, an epitaxial synthetic method, and an organic synthetic method, and furthermore, minute patterning of graphene using a lithography process has been proposed. Because graphene has very useful characteristics that are different from those of existing materials, various studies have been conducted to apply graphene to electronic devices.

SUMMARY

Example embodiments provide a graphene structure having various three-dimensional (3D) shapes formed of graphene and a method of forming the graphene structure having various 3D shapes. Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of example embodiments.

According to example embodiments, a graphene structure may include a graphene structure may include a template having a three-dimensional (3D) shape, and a graphene configured to cover at least a portion of an outer circumference of the template.

The template may have a rod shape and the graphene may be configured to surround the outer circumference of the template. The template may be at least one of a nanowire and a nanorod. The template may be formed of germanium (Ge) or may include a Ge coating on a surface thereof.

According to example embodiments, a graphene structure may include graphene formed in a hollow tube.

According to example embodiments, a graphene structure may include a first supporting layer, a first graphene on the first supporting layer, a second supporting layer on the first graphene and a second graphene on the second supporting layer.

The first and second supporting layers may be formed of Ge or may include a Ge coating on upper surfaces thereof. At least one of the first graphene and the second graphene may be patterned. The graphene structure may further include a third supporting layer on the second graphene, and a third graphene on the third supporting layer to form a multi-layer graphene structure. The multi-layer graphene structure may include a plurality of holes therein.

According to example embodiments, a graphene structure may include a first graphene, a second graphene separated from a surface of the first graphene in a perpendicular direction, and a third graphene configured to cross the first graphene and the second graphene and support the first graphene and the second graphene.

According to example embodiments, a method of forming a graphene structure may include placing a three dimensional template in a reaction chamber, the template including at least a surface formed of a first germanium (Ge) layer, and growing a first graphene along an outer circumference of the first Ge layer by supplying a carbon containing gas into the reaction chamber.

The template may have a rod shape. The template may be the first Ge layer, and may be removed after forming the first graphene. The template may be formed of a non-Ge material, and the first Ge layer may be formed on at least a portion of the template.

The first Ge layer may be removed after forming the first graphene. The first Ge layer may be formed according to a pattern and the first graphene may be grown along the pattern of the Ge layer.

The method may further include forming a second Ge layer on the first graphene, and forming a second graphene on the second Ge layer. Forming the second Ge layer on the first graphene may include forming a non-Ge layer on the first graphene using a non-Ge material, and forming a second Ge layer on the non-Ge layer.

The method may further include forming a multi-layer graphene by repeatedly stacking another Ge layer and another graphene on the second graphene. The method may further include forming a plurality of holes in the multi-layer graphene, and filling the plurality of holes with a functional material. The method may further include etching the first graphene and the second graphene according to a pattern.

Edges of the first graphene and the second graphene exposed by etching may be hydrogen-terminated or treated with functional groups. The method may further include forming a third graphene on side surfaces of the first graphene and the second graphene exposed by etching. The first Ge layer and the second Ge layer may be removed after the forming the third graphene. The first through third graphenes may be at least one of a one-atom layer, two-atom layers and three-atom layers.

The method of forming a graphene structure according to example embodiments facilitates to readily realize a three-dimensional shape of the graphene. The graphene structure can be used for realizing a three-dimensional shape of an electronic circuit, an electronic device, an optical device, or an energy device. Furthermore, the graphene structure can be used for realizing a nano-sized mechanical structure.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. In the drawings, like reference numerals refer to like elements throughout and lengths and sizes of layers and regions may be exaggerated for clarity.

In the present specification, the term “graphene” refers to poly-cyclic aromatic molecules formed of a two-dimensional (2D) carbon hexagonal plane, that is, a 2D thin film having a honeycomb structure formed by a covalent bond of a plurality of carbon atoms. The carbon atoms that are connected to each other through a covalent bond form a six-membered ring as a basic repeating unit. However, the structure of the carbon atoms may further include a five-membered ring and/or a seven-membered ring. Therefore, the graphene looks like a single layer of covalent-bonded (sp2hybridization) carbon atoms. The graphene may have various structures, and the structure varies according to the five-membered ring of the seven-membered ring included in the graphene. The graphene may be formed in a one-atom layer, or may be formed of multiple-atom layers by stacking a plurality of carbon atoms.

FIG. 1Ais a schematic perspective view of a graphene structure100according to example embodiments. Referring toFIG. 1A, the graphene structure100may include a template110having a rod shape and a graphene150that surrounds an outer circumference of the template110. The template110has a rod shape, and there is no specific limitation of size and material for forming the template110. The template110may be a nanowire or a nanorod, e.g., a germanium nanowire or a silicon nanowire. In some cases, the template110may have a size in a range from about a few pm to about a few mm or more. In example embodiments, when the graphene structure100is used as a carrier for a functional material, the template110may include the functional material.

InFIG. 1A, the template110is depicted in a cylindrical shape, but is not limited thereto. For example, the template110may have various three-dimensional (3D) shapes, e.g., a polygonal column, a sphere, or a polyhedron as shown inFIGS. 1B through 1D.

The graphene150may not be tightly adhered to the template110. For example, when the template110is formed of germanium Ge, because the graphene150is formed on the template110, the graphene150may be tightly adhered to the template110. However, the graphene structure100may be a hollow graphene tube formed of only the graphene150due to the removal of the template110.

When the graphene150has a hollow tube shape, the appearance of the graphene150may be similar to a carbon nanotube. However, the graphene150may be different from the carbon nanotube in that the template110may interact with the graphene150. Also, a typical carbon nanotube, e.g., a multi-walled carbon nanotube, has a diameter of about 100 nm or less. However, the graphene structure100according to example embodiments has no limitation in the size of its diameter. For example, the graphene structure100may be formed to a diameter from about100nm to about 1 mm. Also, the graphene structure100according to example embodiments may be formed to a diameter of about100nm or less. Also, because the graphene150depends on the shape of the template110, when the template110is a polygonal column shape as shown inFIG. 1B, the cross-section of the graphene150may have a polygonal tube shape. For another example, when the template110is a sphere shape as shown inFIG. 1C, the graphene150may have a spherical shell shape. For another example, when the template110is a polyhedron shape as shown inFIG. 1D, the graphene150may have a polyhedral shell shape.

The graphene structure100as described above may be used for devices, sensors, or mechanical structures using the physical and chemical properties of the graphene. Also, because there is no limitation in the material for forming the template110, the graphene structure100may also be used for protecting or transporting a predetermined or given functional material.

FIGS. 2A through 2Dare perspective views showing an example method of forming the graphene structure100ofFIG. 1A, according to example embodiments. Referring toFIG. 2A, the template110formed of Ge may be prepared. For example, the template110may be a Ge nanowire or a mono-crystal Ge rod. Also, the template110may have various 3D shapes, e.g., a polygonal column, a sphere, or a polygon (refer toFIGS. 1B through 1D).

Referring toFIG. 2B, the graphene150may be grown on an outer circumference of the template110. A practical method of forming a graphene using Ge has been disclosed in U.S. patent application Ser. No. 12/976,874, the entire contents of which are hereby incorporated by reference. For example, the graphene150may be formed on an outer circumference of the template110by using a chemical vapor deposition (CVD) method, that is, by injecting a carbon containing gas G into a reaction chamber190after placing the template110in the reaction chamber190as shown inFIG. 2C. More specifically, the carbon containing gas G may be CH4, C2H2, C2H4, or CO.

The graphene150may be formed at a temperature in a range from about 200° C. to 1,100° C. under a chamber pressure in a range from about 0.1 torr to 760 torr for about 10 minutes to about 60 minutes. Ge has a relatively high eutectic temperature of about 937° C. with carbon, and the solubility limit of carbon in Ge may be about 108atom/cm3, which is a relatively low level. That is, because the solubility of carbon is relatively low at a temperature in a range from about 700° C. to about 850° C. which is a typical graphene deposition temperature, carbon may be readily deposited from an outer circumference of the template110, that is, Ge, and thus, may readily form the graphene150having a one-atom layer. Also, the graphene150having multi-atom layers, e.g., two-atom layers, three-atom layers, or more, may be formed by changing the deposition conditions.

As a conventional CVD method of forming graphene, a method of using a metal catalyst has been proposed. However, in the method of using a metal catalyst, the graphene may be contaminated due to insufficient removal of the metal catalyst after growing the graphene, or the graphene may be damaged when the metal catalyst is removed. Also, forming the graphene in a one-atom layer may be difficult because the metal catalyst has a relatively high solubility. However, in the method of forming the graphene according to example embodiments, a metal catalyst may not be used, and thus, the graphene may not be contaminated or damaged by any remaining metal catalyst. Therefore, the graphene150having a one-atom layer can be readily formed.

As depicted inFIG. 2D, the template110formed of Ge may be removed from the resultant product. In example embodiments, Ge may be easily dissolved in a liquid, e.g., water. Accordingly, the template110can be removed by soaking the template110on which the graphene150is grown, and thus, the graphene structure100formed of pure graphene150can be obtained. As described above, the diameter or the length of the template110is not specifically limited. Therefore, the diameter or the length of the graphene150formed by the method according to example embodiments is not limited.

FIGS. 3A through 3Dare perspective views showing another method of forming the graphene structure100ofFIG. 1A, according to example embodiments. Referring toFIG. 3A, a template112may be prepared. The material for forming the template112is not specifically limited. For example, the template112may be formed of glass, sapphire, plastic, a metal, silicon, a silicon oxide, a semiconductor compound, or a composite material. The template112may be a nano structure, e.g., a nanowire or a nanorod, and may have a size in a range from about a few pm to about a few mm or more. As depicted inFIG. 3A, the template112may have a cylindrical shape, or various 3D shapes, e.g., a polygonal column, a sphere, or a polyhedron.

Referring toFIG. 3B, a Ge layer115may be deposited on an outer circumference of the template112. For example, the Ge layer115may be formed by injecting a Ge containing gas, for example, GeH4or Ge Cl4into a reaction chamber (not shown) using a CVD method after placing the template112in the reaction chamber. The Ge layer115may be formed to a thickness in a range from about 10 nm to about 10 pm at a temperature in a range from about 200° C. to about 900° C. under a pressure in a range from about 1 torr to about 300 torr. The Ge layer115may be formed by an atomic layer deposition (ALD) method, a sputtering method, and an electron beam evaporation method besides the CVD method. The Ge layer115may be a mono-crystal layer or a multi-crystal layer.

Referring toFIG. 3C, the graphene150may be grown on an outer circumference of the Ge layer115. The method of forming the graphene150using the Ge layer115may be substantially the same as the method of forming the graphene150described with reference toFIG. 2B.

As depicted inFIG. 3D, only the template112in the graphene150may remain by removing the Ge layer115. At this point, the graphene structure100may include the template112and the graphene150that surrounds the template112. As described above, because there is no specific limitation in the material for forming the template112, the material for forming the template112may be selected as necessary.

When the processes described with reference toFIGS. 3B and 3Care repeated, a structure in which multiple layers of the Ge layer115and the graphene150that surround the outer circumference of the template112having a rod shape may be formed. Also, when the Ge layer115is removed, a structure in which multiple layers of the graphene150that surround the template112having a rod shape may be formed. Each layer of the graphene150may be formed in a one-atom layer because the graphene150may be formed using Ge.

Also, each layer of the graphene150may have two-atom layers or three-atom layers. After forming the graphene150as shown inFIG. 3Cand coating an outer circumference of the graphene150with a non-Ge material, a non-Ge material layer may be formed between multi-layers of graphene while the multiple layers of graphene having a cylindrical shape are formed by performing the processes described with reference toFIGS. 3B and 3C.

FIG. 4is a schematic cross-sectional view of a graphene structure200according to example embodiments. Referring toFIG. 4, the graphene structure200has a stack structure in which a first Ge layer220, a first graphene230, a second Ge layer240, a second graphene250, a third Ge layer260, and a third graphene270may be sequentially formed on a substrate210. The material for forming the substrate210is not specifically limited. When the substrate210is formed of Ge, the first Ge layer220may be omitted. Each of the first through third graphenes230,250, and270may be formed in a one-atom layer, and also may be formed of multi-atom layers, e.g., two-atom layers, three-atom layers or more. When it is considered that typically the graphene is formed in a 2D sheet, the graphene structure in which graphene is stacked as in the graphene structure200according to example embodiments may be understood as a 3D shape.

In example embodiments, the graphene structure200having three layers of graphene is described as an example. However, the graphene structure200according to example embodiments may have a multi-layer graphene structure in which two layers of graphene or more than four layers of graphene are stacked.

FIG. 5is a schematic cross-sectional view of a modified version of the graphene structure200ofFIG. 4. Referring toFIG. 5, a graphene structure201according to the modified version has a structure in which the first through third Ge layers220,240, and260may be removed from the graphene structure200ofFIG. 4, and thus, the graphene230,250, and270remain. The substrate210may also be removed from the first through third graphene230,250, and270(not shown). The graphene structure201according to the modified version has a structure in which the number of atom-layers can be precisely controlled, e.g., the first through third graphene230,250, and270.

FIG. 6is a schematic cross-sectional view of another modified version of the graphene structure200ofFIG. 4. Referring toFIG. 6, a graphene structure202according to the modified version has a structure in which first through third non-Ge layers225,245, and265may be additionally included in the graphene structure200ofFIG. 4. The first non-Ge layer225may be interposed between the substrate210and the first Ge layer220, the second non-Ge layer245may be interposed between the first graphene230and the second Ge layer240, and the third non-Ge layer265may be interposed between the second graphene250and the third Ge layer260.

In a process which will be described later, because the first through third non-Ge layers225,245, and265are not related to the formation of graphene, the materials for forming the first through third non-Ge layers225,245, and265are not specifically limited. All of the first through third non-Ge layers225,245, and265may be formed of the same material or may be formed of materials that are different from each other. The first through third non-Ge layers225,245, and265may be formed of, for example, glass, sapphire, plastic, a metal, silicon, a silicon oxide, a Group III-V semiconductor compound, or a composite material.

FIG. 7is a schematic cross-sectional view of another modified version of the graphene structure200ofFIG. 4. Referring toFIG. 7, a graphene structure203according to the modified version has a structure in which the first through third Ge layers220,240, and260may be removed from the graphene structure202ofFIG. 6, and thus, the first through third graphene230,250, and270and the first through third non-Ge layers225,245, and265remain on the substrate210. Because the graphene structure203has a multi-layer structure in which the first through third graphene230,250, and270and the first through third non-Ge layers225,245, and265are alternately stacked, the graphene structure203is understood as a super-lattice structure.

The graphene structures200,201,202, and203have a very similar structure to a typical semiconductor device, and thus, may be readily applied to various electronic devices, optical devices, and energy devices that may utilize graphene.

FIGS. 8A through 8Eare cross-sectional views showing an example method of forming the graphene structure200ofFIG. 4or the graphene structure201ofFIG. 5.

Referring toFIG. 8A, the first Ge layer220may be formed on the substrate210to a thickness, for example, in a range from about 10 nm to about 10 μm. As described with reference toFIG. 3B, the first Ge layer220may be formed on the substrate210by using a CVD method. Besides using the CVD method, the first Ge layer220may also be formed by using an atomic layer deposition (ALD) method, a sputtering method, or an electron beam evaporation method. In example embodiments, the substrate210may be formed of Ge. In example embodiments, the first Ge layer220may be an upper surface of the substrate210.

Referring toFIG. 8B, the first graphene230may be grown on an upper surface of the first Ge layer220. The method of growing the first graphene230using the first Ge layer220may be substantially the same as the method described with reference toFIG. 2B.

As described above, the process of growing graphene using Ge may be repeatedly performed. As a result, as shown inFIG. 8C, multi-layers of graphene may be formed by sequentially stacking the first Ge layer220, the first graphene230, the second Ge layer240, the second graphene250, the third Ge layer260, and the third graphene270on the substrate210.

In case of a conventional method of growing graphene, after forming the graphene, the graphene may be mechanically or chemically exfoliated in order to be utilized. However, in the method of forming a graphene according to example embodiments, the graphene can be directly stacked, and thus, a multi-layer graphene structure, which is difficult to realize by using the conventional method, can be realized.

As depicted inFIG. 8D, the first through third Ge layers220,240, and260may be removed from the resultant product. As depicted inFIG. 8E, the first through third graphenes230,250, and270remain on the substrate210. In example embodiments, the graphene structure may be formed of multi-layer graphene formed of the first through third graphenes230,250, and270on the substrate210.

Each of the first through third graphenes230,250, and270may be formed in a one-atom layer, and thus, the number of atom-layers can be precisely controlled, e.g., the first through third graphenes230,250, and270in the graphene structure200. If necessary, each of the first through third graphenes230,250, and270may be formed in multi-atom layers, e.g., two-atom layers, three-atom layers or more.

FIGS. 9A through 9Eare cross-sectional views showing an example method of forming the graphene structure202ofFIG. 6or the graphene structure203ofFIG. 7. Referring toFIG. 9A, the first non-Ge layer225may be formed on the substrate210, and the first Ge layer220may be formed on the first non-Ge layer225. The first non-Ge layer225may be formed of any material except Ge.

For example, the first non-Ge layer225may be formed of glass, sapphire, plastic, a metal, silicon, a silicon oxide, a semiconductor compound, or a composite material. The first non-Ge layer225may be formed by using a CVD method, an ALD method, a sputtering method, or an electron beam evaporation method based on the material for forming the first non-Ge layer225.

Referring toFIG. 9B, the first graphene230may be formed on an upper surface of the first Ge layer220. The method of growing the first graphene230by using the first Ge layer220may be substantially the same as the method described with reference toFIG. 2B.

As described above, the process of growing graphene by using Ge may be repeatedly performed. As a result, as shown inFIG. 9C, multi-layers of graphene may be formed by sequentially stacking the first non-Ge layer225, the first Ge layer220, the first graphene230, the second non-Ge layer245, the second Ge layer240, the second graphene250, the third non-Ge layer265, the third Ge layer260, and the third graphene270on the substrate210. The first through third non-Ge layers225,245, and265may be formed of the same material, or may also be formed of materials that are different from each other.

As depicted inFIG. 9D, the first through third Ge layers220,240, and260may be removed. Thus, as depicted inFIG. 9E, a super-lattice structure in which the first through third graphenes230,250, and270and the first through third non-Ge layers225,245, and265are alternately stacked on the substrate210may be formed.

FIG. 10is a schematic cross-sectional view of a graphene structure300according to example embodiments.FIGS. 11A through 11Dare cross-sectional views showing an example method of forming the graphene structure300ofFIG. 10. Referring toFIGS. 10 and 11A, a first Ge layer320having a predetermined or given pattern may be formed on a substrate310. Regions325where the first Ge layer320is not formed may be filled with a material, e.g., silicon, on which the graphene does not grow. Referring toFIGS. 10 and 11B, a first graphene330may be formed on the first Ge layer320. Thus, the first graphene330has a pattern substantially the same as that of the first Ge layer320.

Referring toFIGS. 10 and 11C, a second Ge layer340having a predetermined or given pattern may be formed on a layer on which the first graphene330is formed. Regions345where the first Ge layer340is not formed may be filled with a material, e.g., silicon, on which the graphene does not grow. The first graphene330may be formed of a one-atom layer or few-atom layers, and thus, the thickness of the first graphene330may be negligible.

Referring toFIGS. 10 and 11D, a second graphene350may be formed on the second Ge layer340. The second graphene350has a pattern substantially the same as that of the first Ge layer340. In the same manner, a third Ge layer360(refer toFIG. 10) and a third graphene370(refer toFIG. 10) may also be formed on a layer on which the second graphene350is formed.

The graphene structure300having the above structure as depicted inFIG. 10has a stacking structure in which the first through third graphene330,350, and370may be stacked. The patterns of each of the first through third graphene330,350, and370may be used to realize functions or wiring-circuits of predetermined or given electronic devices.

In example embodiments, the graphene structure300having three layers of graphene may be described as an example. However, the graphene structure300according to example embodiments may have a multi-layer graphene structure in which two layers of graphene or more than four layers of graphene may be stacked.

FIG. 12is a perspective view of a graphene structure400according to example embodiments. The graphene structure400according to example embodiments may have a stacked-column in which first through fourth supporting layers420,440,460and480and first through fourth graphenes430,450,470and490may be alternately stacked on a substrate410. The stack-column may be a modified version of the graphene structure200described with reference toFIG. 4or the graphene structure203described with reference toFIG. 7. That is, the graphene structure400according to example embodiments may be a structure formed by etching all regions of the graphene structures200and203except a predetermined or given region.

Edges430a,450a,470aand490aof the first through fourth graphenes430,450,470and490and edge410aof the substrate may be respectively exposed to the external environment. The materials for forming the first through fourth supporting layers420,440,460and480are not specifically limited. For example, as in the graphene structure200described with reference toFIG. 4, the first through fourth supporting layers420,440,460and480may be formed of Ge.

Alternatively, as in the graphene structure203described with reference toFIG. 7, the first through fourth supporting layers420,440,460and480may be formed of a non-Ge material. The edges430a,450a,470aand490aof the first through fourth graphenes430,450,470and490and the edge410aof the substrate exposed to the external environment may have an arm-chair shape or a zigzag shape according to a cutaway shape due to the etching. The edges410a,430a,450a,470aand490amay be hydrogen-terminated (H-terminated) or treated with predetermined or given functional groups.

FIG. 13is a schematic cutaway perspective view of a graphene structure500according to example embodiments. The graphene structure500may be a modified version of the graphene structure200described with reference toFIG. 4or the graphene structure203described with reference toFIG. 7.

That is, the graphene structure500according to example embodiments may have a porous multi-layer graphene structure in which a plurality of holes580may be formed in multi-layer graphene formed by alternately stacking first through third supporting layers520,540, and560and first through third graphenes530,550, and570on a substrate510.

InFIG. 13, the holes580have a circular shape. However, the shape of the holes580according to example embodiments is not limited thereto. That is, the holes580may have a polygonal shape or any other shape. A functional material may be injected into the holes580. For example, when the holes580have a size in a range from a few nm to a few tens of nm, a material, e.g., quantum dot phosphor, may be injected into the holes580.

FIG. 14is a schematic perspective view of a graphene structure600according to example embodiments.FIGS. 15A through 15Dare cross-sectional views showing an example method of forming the graphene structure600ofFIG. 14. Referring toFIG. 15A, a multi-layer graphene may include first through third Ge layers620,640, and660and first through third graphenes630,650, and670alternately stacked on a substrate610. The multi-layer graphene may be the graphene structure200described with reference toFIG. 4.

Referring toFIG. 15B, the multi-layer graphene may be etched to a predetermined or given pattern. Side surfaces of each of the first through third Ge layers620,640, and660and an edge of each of the first through third graphenes630,650, and670may be exposed to the external environment on side surfaces of etched regions680.

Referring toFIG. 15C, a side graphene690may be formed on the side surfaces of each of the exposed first through third Ge layers620,640, and660. The side graphene690may be connected to the edge of each of the first through third graphenes630,650, and670which are exposed in the etched regions680. Thus, a 3D shape formed of the side surfaces of the first through third graphene630,650, and670and the side graphene690may be realized.

As depicted inFIG. 15D, the first through third Ge layers620,640, and660may be removed from the resultant product. Even though not illustrated, the side graphene690may not be formed on portions of the side surfaces of the first through third Ge layers620,640, and660. When the first through third Ge layers620,640, and660are removed as described above, a 3D structure formed of only the first through third graphene630,650, and670and the side graphene690may be realized. When the substrate610is removed, a 3D structure formed of pure graphene may be realized.

The structures described above are example 3D shapes realized by graphene. Also, various 3D shapes may be realized by limiting the regions on which the side graphene690is formed, by forming each of the first through third graphene630,650, and670in a predetermined or given pattern, or by applying the methods described in example embodiments. The graphene having a 3D shape may be used for realizing a 3D device, e.g., an electronic circuit, an electronic device, an optical device, or an energy device, and furthermore, used for realizing a nano-sized mechanical structure.

In example embodiments, the graphene structure600having three layers of graphene is merely an example. The graphene structure600according to example embodiments may have a multi-layer graphene structure in which two layers of graphene or more than four layers of graphene may be stacked.

While the graphene structure and the method of forming the same have been particularly shown and described with reference to example embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the following claims.