KR20150057564A - Graphene film and method for manufacturing the same - Google Patents

Abstract

The present invention relates to graphene, and more particularly, to a graphene film and a manufacturing method thereof. The present invention provides a graphene film comprising: a substrate; A graphene layer positioned on the substrate; And a charge transport layer disposed between the substrate and the graphene layer and including a plurality of nanowires.

Description

Graphene film and method for manufacturing the same

The present invention relates to graphene, and more particularly, to a graphene film and a manufacturing method thereof.

As materials composed of carbon atoms, fullerene, carbon nanotube, graphene, graphite and the like exist. Among them, graphene is a structure in which carbon atoms are composed of one layer on a two-dimensional plane.

In particular, graphene is not only very stable and excellent in electrical, mechanical and chemical properties, but it is also a good conductive material that can move electrons much faster than silicon and can carry much larger currents than copper, It has been proved through experiments that a method of separation has been discovered.

Such graphene can be formed in a large area and has electrical, mechanical and chemical stability as well as excellent conductivity, and thus is attracting attention as a basic material for electronic circuits.

In addition, since graphenes generally have electrical characteristics that vary depending on the crystal orientation of graphene of a given thickness, the user can express the electrical characteristics in the selected direction and thus design the device easily. Therefore, graphene can be effectively used for carbon-based electric or electromagnetic devices.

In recent years, improving the surface resistance of graphene has become an important issue. In the case of graphene synthesized by the conventional chemical vapor deposition (CVD) method, there is a crystal boundary where the charge carrier can scatter, and a method for solving the problem is needed.

SUMMARY OF THE INVENTION The present invention provides a graphene film which can improve the electrical characteristics of graphene by allowing electrons to be transmitted over the crystal boundary of graphene, and a method for producing the graphene film.

According to a first aspect of the present invention, there is provided a graphene film comprising: a substrate; A graphene layer positioned on the substrate; And a charge transport layer disposed between the substrate and the graphene layer and including a plurality of nanowires.

Here, a graphene layer may be further disposed between the substrate and the charge transport layer.

Here, the charge transport layer may form a two-dimensional layered nanowire layer by connecting at least a portion of the plurality of nanowires to each other.

At this time, the charge transport layer may include two or more layers of nanowires.

Here, the nanowire may include at least one of Ni, Pt, Au, and Ag.

Here, the nanowires may be for electrically connecting crystal boundaries of the graphene layer.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: preparing a graphene layer formed on a growth substrate; Transferring the graphene layer to a transfer substrate; Forming a charge transport layer including a plurality of nanowires on the graphene layer transferred to the transfer substrate; And transferring the charge transport layer and the graphene layer to a final substrate.

Here, the step of transferring onto the final substrate may be performed so that the charge transport layer contacts the final substrate.

The forming of the charge transport layer may include: preparing a dispersion in which nanowires are dispersed in a solvent; And adsorbing the nanowires on the graphene layer.

Here, the step of transferring to the final substrate may be transferred to the final substrate provided with the graphene layer.

Here, the charge transport layer may include a plurality of nanowire layers.

At this time, the step of transferring to the final substrate can be transferred to the final substrate provided with the nanowire layer on the graphene layer.

The present invention has the following effects.

The charge transport layer including the nanowire can improve the electrical conductivity of the graphene layer and improve the surface resistance of the graphene layer.

That is, since the charge transport layer is adsorbed and positioned in the region including the crystal boundary of the graphene layer, the surface resistance of the graphene layer can be improved.

On the other hand, the graphene layer covers the charge transport layer to prevent the nanowires from being exposed, thereby preventing oxidation of the nanowires and improving reliability.

1 is a cross-sectional view showing an example of a graphene film of the present invention.
2 is a photomicrograph showing an example of a nanowire.
3 is a cross-sectional view showing another example of the graphene film of the present invention.
4 is a cross-sectional view showing still another example of the graphene film of the present invention.
5 to 13 are a cross-sectional view and a schematic view showing a method for producing the graphene film of the present invention.

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

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. Rather, the intention is not to limit the invention to the particular forms disclosed, but rather, the invention includes all modifications, equivalents and substitutions that are consistent with the spirit of the invention as defined by the claims.

It will be appreciated that when an element such as a layer, region or substrate is referred to as being present on another element "on," it may be directly on the other element or there may be an intermediate element in between .

Although the terms first, second, etc. may be used to describe various elements, components, regions, layers and / or regions, such elements, components, regions, layers and / And should not be limited by these terms.

1 is a cross-sectional view showing an example of a graphene film of the present invention.

1, a graphene film 20 includes a graphene layer 20 on a substrate 50, and a plurality of nanowires 41 (also referred to as a " graphene layer " 9). The charge transport layer 40 may be formed of a conductive material.

This charge transport layer 40 means a layer capable of transporting electrons such as electrons across a crystal boundary that may be present in the graphene layer 20, Can be used.

A nanowire (nanotape) refers to a wire structure having a size in nanometers (nm) in diameter. It is generally referred to as nanowires with diameters of less than 10 nm, nanowires of several hundreds of nm in diameter, and there is no particular limitation in the length direction.

In the very micro world, the influence of the quantum mechanical effect is dominant, and such a wire structure is also called a quantum wire. There exist many types of nanowires such as metallic (Ni, Pt, Au, etc.), semiconductors (Si, InP, GaN, ZnO and the like) and insulating properties (SiO ₂ , TiO ₂ and the like) .

That is, the nanowire 41 used in the charge transport layer 40 may include at least one of Ni, Pt, Au, and Ag. Among them, silver (Ag) nanowire 41 can be used. FIG. 2 shows an example of such a silver nanowire.

In this charge transport layer 40, at least a portion of the plurality of nanowires 41 may overlap each other to form a two-dimensional layered nanowire layer.

The charge transport layer 40, in which the nanowires 41 are layered, is adsorbed and positioned on the graphene layer 20.

Therefore, this charge transport layer 40 can improve the electrical conductivity of the graphene layer 20 and improve the surface resistance of the graphene layer 20.

When the graphene layer 20 is formed on the catalytic metal layer by a method such as chemical vapor deposition (CVD), a plurality of island-like shapes are formed at the beginning of growth, They are connected to each other and have a layered structure.

At this time, the crystal boundary between the island and the island can be referred to as a crystal boundary. In such a crystal boundary, the charge mobility may be reduced and the resistance may be relatively large.

The charge transfer layer 40 can improve the surface resistance of the graphene layer 20 because the nanowire 41 is adsorbed and positioned in a region including such crystal boundaries.

Here, the graphene layer 20 is a graphene layer formed on the catalytic metal layer, that is, a thin film graphene layer. However, other graphene oxide or graphene oxide graphene Reduced graphene may also be used.

That is, even when the graphene layer 20 including the oxidized graphene or the reduced graphene is used together with the charge transport layer 40, the above-described effects such as improvement in surface resistance can be exhibited.

On the other hand, the graphene layer 20 covers the charge transport layer 40 to prevent the nanowire 41 from being exposed, thereby preventing oxidation of the nanowire 41 and improving reliability.

That is, since graphene has an oxidation-preventing ability, the graphene layer 20 covering the charge transport layer 40 can prevent oxidation of the nanowire 41 made of a metal.

Here, the substrate 50 may be a layer that can be directly bonded to various electronic devices together with the graphene layer 20, or may be a part of the electronic device.

The substrate 50 may be made of a material such as PET (polyethyleneterephthalate), TAC (triacetyl cellulose), and PC (poly carbonate).

3 is a cross-sectional view showing another example of the graphene film of the present invention.

As shown in FIG. 3, a graphene layer 21 may further be provided between the substrate 50 and the charge transport layer 40 in the state of FIG. That is, another graphene layer 21 may be further disposed on the substrate 50.

At this time, the nanowire 41 constituting the charge transport layer 40 is positioned between the two graphene layers 20 and 21, so that it can be further protected against the phenomenon of oxidation and the like.

In addition, the charge transfer layer 40 can improve the charge mobility of the two graphene layers 20 and 21, thereby improving the electrical characteristics of the entire graphene film.

4 is a cross-sectional view showing another example of the graphene film of the present invention.

As shown in Fig. 4, the charge transport layers 40 and 44 may be composed of a plurality of layers. That is, the charge transport layer 40 adsorbed on the graphene layer 21 located on the substrate 50 side and the charge transport layer 44 adsorbed on the graphene layer 20 located on the upper side have.

At this time, the two charge transport layers 40 and 44 may be positioned in contact with each other.

The graphene film including the two layers of charge transport layers 40 and 44 and the two layers of graphene layers 20 and 21 can further improve the electrical characteristics as compared with the case of FIG.

Hereinafter, a method for producing a graphene film as described above will be described with reference to Figs. 5 to 13. Fig.

First, as shown in FIG. 5, a graphene layer 20 is formed on a growth substrate 10. As the growth substrate 10 for growing the graphene layer 20, a catalytic metal layer may be used. Hereinafter, the case of using the catalyst metal layer as the growth substrate 10 will be described as an example.

The catalyst metal layer 10 may be formed of a metal such as Ni, Co, Fe, Pt, Au, Al, Cr, Cu, Mg, Mn, Mo, Rh, Si, Ta, Ti, W, And may be used as a single layer of any one of them, or as an alloy of at least two of them.

6 shows an example in which the graphene layer 20 is formed on the catalyst metal layer 10 by chemical vapor deposition (CVD).

This chemical vapor deposition method is a method of growing the graphene layer 20 by placing the catalyst metal layer 10 in the chamber 200, introducing a carbon source, and providing suitable growth conditions.

Examples of the carbon source include a gas such as methane (CH ₄ ), acetylene (C ₂ H ₂ ), etc., and a solid form such as powder or polymer and a liquid such as bubbling alcohol It is possible.

In addition, various carbon sources such as ethane, ethylene, ethanol, acetylene, propane, butane, butadiene, pentane, pentene, cyclopentadiene, hexane, cyclohexane, benzene, toluene,

Hereinafter, examples in which copper (Cu) is used as the catalyst metal layer 10 and methane (CH ₄ ) is used as a carbon source will be described.

When methane gas is introduced into the hydrogen atmosphere while maintaining a proper temperature on the catalyst metal layer 10, the hydrogen reacts with methane to form the graphene layer 20 on the catalyst metal layer 10. The formation of the graphene layer 20 may be performed at a temperature of approximately 300 to 1500 ° C.

At this time, if there is no space on the lower surface of the catalytic metal layer 10, the graphene layer 20 may be formed only on the upper surface of the catalytic metal layer 10. However, if there is a space on the lower surface of the catalytic metal layer 10, A graphene layer 20 may be formed on both sides of the metal layer 10.

As the catalytic metal layer 10, copper has a low solubility in carbon and may be advantageous to form a mono-layer of graphene. This graphene layer 20 may be formed directly on the catalytic metal layer 10.

The catalytic metal layer 10 may be supplied in the form of a sheet but may be fed continuously while being wound on the roller 100 as shown in Figure 6 and may have a thickness of about 10 탆 to 10 mm, Type catalytic metal layer 10 may be used.

If the graphene layer 20 is formed on both surfaces of the graphene layer 20 formed by the above process, the graphene layer 20 formed on one side of the catalyst metal layer 10 may be removed .

5, a graphene layer 20 may be formed on one surface of the catalytic metal layer 10. As shown in FIG.

Thereafter, the transfer substrate 30 is placed on the graphene layer 20 as shown in Fig. Such a transfer substrate 30 can use a film such as a heat transfer film and a light transfer film. At this time, pressure can be applied so that the transition substrate 30 can be closely adhered to the graphene layer 20.

The transition substrate 30 may include an adhesive layer adhered to the graphene layer 20, but a description thereof will be omitted here.

Next, a process for removing the catalyst metal layer 10 is performed. This process can be removed by etching the catalytic metal layer 10, or by removing it from the graphene layer 20 by applying a mechanical force.

Removal of the catalytic metal layer 10 through etching can remove the catalytic metal layer 10 by allowing only the catalytic metal layer 10 to be immersed in an etching solution (not shown) in the state of FIG.

When the catalyst metal layer 10 is removed by this process, the graphene layer 20 is attached to the transition substrate 30 as shown in FIG.

Next, as shown in FIG. 9, the charge transport layer 40 having the two-dimensional structure of the nanowire 41 is formed on the graphene layer 20.

This charge transport layer 40 can be formed by using the dispersion solution 42 in which the nanowires 41 are dispersed, as shown in Fig.

That is, the graphene layer 20 attached to the transfer substrate 30 described above is brought into contact with or immersed in the container 43 containing the dispersion solution 42 in which the nanowires 41 are dispersed, Can be uniformly adsorbed on the graphene layer (20).

Through the above process, the charge transport layer 40 in which the nanowires 41 are uniformly adsorbed on the graphene layer 20 can be formed.

Then, when the charge transfer layer 40 and the graphene layer 20 are transferred to a substrate 50 (hereinafter, referred to as a final substrate) which can be used for the final device, the structure shown in FIG. 1 can be achieved.

12, when the charge transfer layer 40 and the graphene layer 20 are transferred to the final substrate 50 as described above, the graphene layer 21 is transferred to the substrate 50, Can be transferred.

In this case, the structure shown in FIG. 3 in which the charge transport layer 40 is located between the two graphene layers 20 and 21 can be made.

On the other hand, when the charge transport layer 40 and the graphene layer 20 are transferred to the final substrate 50, as shown in Fig. 13, The transfer layer 44 can be transferred in a state where the transfer layer 44 is positioned.

The structure shown in FIG. 4 in which two layers of the charge transport layers 40 and 44 are located between the two graphen layers 20 and 21 can be made.

On the other hand, as described above, in addition to the thin film graphenes described in the above manufacturing process, oxidized graphene or reduced graphene can be used.

In this case, the process of forming the graphene layer 20 on the catalyst metal layer 10 and transferring it to the transition substrate 30 may be omitted.

In other words, the graphene layer 20 containing oxidized graphene or reduced graphene may be substituted on the substrate such as the transfer substrate 30.

In other cases, the description using thin film graphene can be applied as it is.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

10: catalytic metal layer 20, 21: graphene layer
30: transfer substrate 40, 44: charge transfer layer
41: nanowire 42: dispersion solution
43: vessel 50: final substrate

Claims (12)

In the graphene film,
Board;
A graphene layer positioned on the substrate; And
And a charge transport layer disposed between the substrate and the graphene layer and including a plurality of nanowires. The graphene film of claim 1, further comprising a graphene layer between the substrate and the charge transport layer. The graphene film of claim 1, wherein the charge transport layer is formed by connecting at least a portion of a plurality of nanowires to each other to form a two-dimensional layered nanowire layer. 4. The graphene film of claim 3, wherein the charge transport layer comprises two or more layers of nanowires. The graphene film according to claim 1, wherein the nanowire comprises at least one of Ni, Pt, Au and Ag. The graphene film of claim 1, wherein the nanowires are for electrically connecting crystal boundaries of the graphene layer. Preparing a graphene layer formed on a growth substrate;
Transferring the graphene layer to a transfer substrate;
Forming a charge transport layer including a plurality of nanowires on the graphene layer transferred to the transfer substrate; And
And transferring the charge transport layer and the graphene layer to a final substrate. 8. The method of manufacturing a graphene film according to claim 7, wherein the step of transferring to the final substrate comprises transferring the charge transfer layer to contact the final substrate. 8. The method of claim 7, wherein forming the charge transport layer comprises:
Preparing a dispersion in which nanowires are dispersed in a solvent; And
And adsorbing the nanowires on the graphene layer. 8. The method of claim 7, wherein the step of transferring to the final substrate is carried out on a final substrate provided with a graphene layer. 8. The method of claim 7, wherein the charge transport layer comprises a plurality of nanowire layers. The method of claim 11, wherein the step of transferring to the final substrate is performed on the final substrate provided with the nanowire layer on the graphene layer.

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