KR102352572B1 - Graphene quantum dot pattern and preparing method thereof - Google Patents

Abstract

The present invention relates to: a graphene quantum dot pattern comprising a substrate, and graphene quantum dots patterned on the substrate; and a method for manufacturing the same. According to the present invention, without the use of an etchant, acid or harmful chemical on the substrate, through a bottom-up method, specifically, through ion beam irradiation, by forming small-sized metal catalyst particles, the final patterning of graphene quantum dots whose size is controlled to be constant can be selectively performed.

Description

Graphene quantum dot pattern and manufacturing method thereof

The present invention relates to a method of selectively patterning graphene quantum dots on a substrate through a bottom-up method, specifically, through ion beam irradiation.

In general, materials used as bio-imaging, contrast agents, and drug carriers are mostly inorganic substances that are harmful to the human body, and have various side effects such as shock and accumulation in the body. Recently, attempts to solve these side effects by using quantum dots having light emitting properties are being researched around the world. Among them, graphene quantum dots of carbon-based materials are receiving great attention in consideration of biocompatibility. Graphene quantum dots are zero-dimensional carbon-based nanomaterials with a size of several to tens of nm or less, and have light-emitting characteristics in the visible range.

Currently, a representative method for manufacturing graphene quantum dots is based on a chemical process. Graphite or 2D graphene is split by acid in a top-down manner, or organic precursors are used for biocompatibility, but the use of surfactants or other chemicals is always required to manufacture graphene quantum dots. There are substances that are known to be harmful to the human body, such as acids, but chemical residues are even more dangerous because we do not know what effect they will have if they enter the body. In addition, there is an effort to completely remove the used chemicals, but there is no choice but to leave a fine residual amount, and if it does, it will also cause harm to the human body. It can be said that it is difficult to apply directly to

In this regard, it can be said that the current bottom-up method of growing graphene quantum dots from a small seed using a catalyst has the same problem. In the conventional bottom-up method for manufacturing graphene quantum dots, an etchant, acid, or harmful chemical is used in the process of removing the substrate and catalyst or transferring the graphene quantum dots after manufacturing the graphene quantum dots. have. That is, pure carbon nanomaterials or graphene quantum dots can be manufactured, but there are many materials that are not suitable for the human body. In addition, with the existing process, it is difficult to control the size and characteristics of graphene quantum dots, and it is also difficult to manufacture high-quality graphene quantum dots. can be said to be large.

In addition, in the case of manufacturing graphene quantum dots by an existing chemical process, since the graphene quantum dots prepared in this way exist in a liquid phase, for the production of an electric and electronic device, an electrode is first patterned, and then graphene quantum dots are dropped thereon. There was a limit to the production of electrical and electronic devices because it could only be used as a method. That is, there is no existing research on a technique for selectively and directly patterning graphene quantum dots only at desired positions on a substrate.

CN 104787756 A (2015. 07. 22)

The present invention provides a graphene quantum dot in a state in which the size is constantly controlled, through a bottom-up method, specifically, through ion beam irradiation, without the use of an etchant, acid or harmful chemicals on the substrate. To provide a method for selectively patterning

However, the technical problem to be achieved by the present invention is not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

The present invention is a substrate; And it provides a graphene quantum dot pattern comprising the graphene quantum dots patterned on the substrate.

In one embodiment of the present invention, the method comprising: (a) implanting a metal catalyst source into a substrate through selective ion beam irradiation; (b) forming metal catalyst particles by heating the substrate onto which the metal catalyst source is injected; and (c) providing a gaseous carbon flow on the substrate on which the metal catalyst particles are formed to pattern the graphene quantum dots.

According to the present invention, without the use of an etchant, acid or harmful chemical on a substrate, through a bottom-up method, specifically, through ion beam irradiation, by forming small-sized metal catalyst particles, the The final patterning of graphene quantum dots whose size is controlled to be constant can be selectively performed. In addition, after the final patterning of the graphene quantum dots, there is an advantage that the metal catalyst particles of a small size used can be evaporated and removed due to a high temperature atmosphere without additional processing.

In particular, according to the present invention, graphene quantum dots can be selectively and directly patterned only at desired positions on a substrate, which is very advantageous for application to electrical and electronic devices that are in the spotlight these days.

The graphene quantum dot pattern prepared according to the present invention can not only replace materials used as bio-imaging, contrast agents, and drug carriers, which have many side effects, but also can be utilized in various pharmaceutical fields by using the luminescent properties of the graphene quantum dot pattern. can In addition, although recently developed using the light emitting characteristics of the graphene quantum dot pattern prepared according to the present invention, most of the elements harmful to the human body such as cadmium and iron are utilized, which can greatly contribute to the development of the transparent flexible display field, which is a problem. .

In addition, by using the semiconductor properties of the graphene quantum dot pattern prepared according to the present invention, it is possible to help not only the decomposition of water pollutants, which has recently been an issue, but also the development of the photocatalyst field capable of hydrogen production, and in addition, the present invention By using the excellent thermal and electrical conductivity of the graphene quantum dot pattern prepared according to the method, the field of application can be further expanded.

1 is a diagram schematically illustrating a method for selectively patterning graphene quantum dots on a substrate according to an embodiment of the present invention.
2 is an SEM photograph and AFM photograph showing metal catalyst particles formed on a substrate during the manufacturing process of the graphene quantum dot pattern according to Example 1. FIG.
3 is a TEM photograph and a Raman spectroscopy graph for analyzing the characteristics of graphene quantum dots patterned according to Example 1. FIG.
4 is a TEM photograph and lattic spacing analysis results of analyzing the characteristics of graphene quantum dots patterned according to Example 1. FIG.
5 is an FT-IR graph, an EDX graph, and an XPS graph analyzing the characteristics of graphene quantum dots patterned according to Example 1.
6 is an SEM photograph, an EDX photograph, and an EDX mapping graph showing whether a graphene quantum dot pattern is selectively formed on a substrate according to Example 1;
7 is an SEM photograph showing whether a graphene quantum dot pattern is selectively formed on a substrate according to Example 2. FIG.

The present inventors applied selective ion beam irradiation under optimized conditions while studying a method for patterning graphene quantum dots through a bottom-up method without the use of etchants, acids or harmful chemicals on the substrate. . As a result, it was confirmed that the size of the graphene quantum dots can be uniformly controlled while selectively and directly patterning the graphene quantum dots only at desired positions on the substrate, and the present invention has been completed.

As used herein, the term "graphene quantum dots" refers to a 0-dimensional carbon-based nanomaterial having a size of several to tens of nm or less, and has light emission characteristics in the visible light region, and such light emission characteristics may vary depending on the size. The size of the graphene quantum dots depends on the size of the metal catalyst particles used, and the size of the graphene quantum dots is preferably 0.1 nm to 50 nm, more preferably 0.1 nm to 10 nm, and 1 nm to 5 nm. It is most preferably nm, but is not limited thereto. On the other hand, the graphene quantum dots may form a honeycomb lattice having a lattice spacing of 0.1 nm to 0.4 nm, wherein the lattice spacing means a direction perpendicular to the growth direction of the graphene quantum dots, and is denoted by _{d 1} or d ₂ can be

Hereinafter, the present invention will be described in detail.

Graphene Quantum Dot Pattern

The present invention is a substrate; And it provides a graphene quantum dot pattern comprising the graphene quantum dots patterned on the substrate.

First, the graphene quantum dot pattern according to the present invention includes a substrate, the substrate may represent one layer or a plurality of layers, and the substrate may be made of various materials such as silicon, silicon oxide, silicon carbide, and glass. have.

Next, the graphene quantum dot pattern according to the present invention includes graphene quantum dots patterned on the substrate, and patterning on the substrate may mean selectively forming only a desired position on the substrate. .

According to the present invention, unlike graphene quantum dots manufactured by a conventional chemical process, there is an advantage in that graphene quantum dots can be selectively and directly patterned only at desired positions on a substrate. The patterning may be implemented through selective ion beam irradiation, which will be described later.

Manufacturing method of graphene quantum dot pattern

The present invention comprises the steps of: (a) implanting a metal catalyst source into a substrate through selective ion beam irradiation; (b) forming metal catalyst particles by heating the substrate onto which the metal catalyst source is injected; and (c) providing a gaseous carbon flow on the substrate on which the metal catalyst particles are formed to pattern the graphene quantum dots.

First, the method for manufacturing a graphene quantum dot pattern according to the present invention includes injecting a metal catalyst source into a substrate [step (a)] through selective ion beam irradiation.

As used herein, "ion beam irradiation" refers to ion beam implantation, which is a technique for evenly injecting an ion-type catalyst source into a substrate by adjusting the ion beam irradiation amount and ion beam irradiation energy. It is different from other deposition techniques such as plasma and ion beam sputtering. can be broadly distinguished. In particular, if a sputtering technique such as ion beam sputtering is used, since the catalyst source in the form of ions is deposited only on the surface of the substrate, there is a problem that the catalyst particles are randomly entangled with each other. cannot be manufactured

In particular, when the selective ion beam irradiation is used, there is an advantage that graphene quantum dots can be selectively and directly patterned only on a desired position on a substrate. For this purpose, the selective ion beam irradiation includes ion beam irradiation using a shadow mask; Alternatively, it may be focused ion beam irradiation. In this case, when the ion beam is irradiated using the shadow mask, the ion beam can selectively pass only in the region not covered by the shadow mask, and the graphene quantum dots can be patterned to correspond to the shadow mask pattern. In addition, when the focused ion beam is irradiated, the ion beam can pass through only the focus region. However, in the case of focused ion beam irradiation, there is a limitation in that it is difficult to control the size of the focused ion beam to a size of several nanometers due to the repulsive force between ion particles. Therefore, ion beam irradiation using a shadow mask is more preferable, but is not limited thereto.

The ion beam irradiation amount may be 1 X 10 ¹³ ion/cm ² to 1 X 10 ¹⁹ ion/cm ² , preferably 1 X 10 ¹³ ion/cm ² to 5 X 10 ¹⁵ ion/cm ² , but not limited thereto does not In this case, when the ion beam irradiation amount is too low, it is impossible to effectively inject the metal catalyst source into the substrate, and accordingly, there is a problem in that the density of the metal catalyst particles formed on the substrate is too low. On the other hand, since the size of the final patterned graphene quantum dots increases as the ion beam irradiation amount increases, in order to prevent carbon nanotubes (CNTs) from being produced instead of the graphene quantum dots, the ion beam irradiation amount is 5 X 10 ¹⁵ ion/cm ² or less is preferable, and 5 X 10 ¹⁴ ion/cm ² or less is more preferable, but is not limited thereto.

The ion beam irradiation energy may be 10 keV to 1 MeV or less, preferably 35 keV to 60 keV, but is not limited thereto. At this time, when the ion beam irradiation energy is too low, ion species rise better to the surface during heating after ion beam irradiation, and large metal catalyst particles are generated. , there is an effect that the size of the metal catalyst particles produced becomes smaller as there are fewer ionic species that rise to the surface during heating.

The metal catalyst source is provided in the form of ions for use in ion beam irradiation, and may include one or more metal ions selected from the group consisting of copper, iron, platinum, indium, and nickel, but is not limited thereto. In order to keep the size of the final patterned graphene quantum dots small by keeping the size of the intermediately prepared metal catalyst particles small, it is preferable to include iron ions, but the present invention is not limited thereto.

Next, the method for producing a graphene quantum dot pattern according to the present invention includes a step [(b) step] of forming metal catalyst particles by heating the substrate into which the metal catalyst source is injected.

By heating the substrate into which the metal catalyst source is injected, the metal catalyst source may rise to the surface of the substrate to form metal catalyst particles on the substrate. Accordingly, the metal catalyst particles are evenly distributed on the substrate, and there is an advantage in that it is possible to prevent a phenomenon in which they are arbitrarily entangled with each other. In this case, the formation of the metal catalyst particles means that the metal catalyst particles are patterned to correspond to selective ion beam irradiation.

The heating is a primary heating, and may be performed at a temperature of 800° C. to 1200° C. under an inert gas atmosphere. As the heating temperature increases, metal catalyst particles having a smaller size may be formed, thereby reducing the size of the final patterned graphene quantum dots.

The size of the metal catalyst particles is a factor influencing the size of the graphene quantum dots, and may be adjusted according to an ion beam irradiation amount, a type of a metal catalyst source, and a heating temperature. The size of the metal catalyst particles is preferably 0.1 nm to 50 nm, more preferably 0.1 nm to 10 nm, most preferably 1 nm to 5 nm, but is not limited thereto.

Next, the method for producing a graphene quantum dot pattern according to the present invention includes a step [(c) step] of patterning the graphene quantum dots by providing a gaseous carbon flow on the substrate on which the metal catalyst particles are formed.

The patterning of the graphene quantum dots may be performed for 10 minutes to 1 hour at a temperature of 800 °C to 1200 °C under an inert gas atmosphere. The patterning of the graphene quantum dots is a secondary heating, and may be performed under the same temperature condition as the primary heating or a higher temperature condition than the primary heating, preferably performed at a temperature of 900 ° C. to 1200 ° C., 1000 It is more preferably carried out at a temperature of ℃ to 1200 ℃, but is not limited thereto. In this case, the metal catalyst particles are nano-sized, and since the melting point is significantly lower than that of the bulk material, all of them may be removed during the secondary heating. In addition, as the secondary heating temperature increases, there is an advantage in that the crystallinity of the quantum dots of graphene is improved.

The flow rate of the gaseous carbon may be 5 sccm to 500 sccm, preferably 5 sccm to 50 sccm, and more preferably 5 sccm to 30 sccm, but is not limited thereto. As the flow rate of the gaseous carbon decreases, the size of the final patterned graphene quantum dots may decrease.

After step (c), the metal catalyst particles may be removed without additional treatment. Since the metal catalyst particles are small in size, they can be easily evaporated and removed due to a high temperature atmosphere.

According to the present invention, without the use of an etchant, acid or harmful chemical on a substrate, through a bottom-up method, specifically, through ion beam irradiation, by forming small-sized metal catalyst particles, the The final patterning of graphene quantum dots whose size is controlled to be constant can be selectively performed. In addition, after the final patterning of the graphene quantum dots, there is an advantage that the metal catalyst particles of a small size used can be evaporated and removed due to a high temperature atmosphere without additional processing.

In particular, according to the present invention, graphene quantum dots can be selectively and directly patterned only at desired positions on a substrate, which is very advantageous for application to electrical and electronic devices that are in the spotlight these days.

The graphene quantum dot pattern prepared according to the present invention can not only replace materials used as bio-imaging, contrast agents, and drug carriers, which have many side effects, but also can be utilized in various pharmaceutical fields by using the luminescent properties of the graphene quantum dot pattern. can In addition, although recently developed using the light emitting characteristics of the graphene quantum dot pattern prepared according to the present invention, most of the elements harmful to the human body such as cadmium and iron are utilized, which can greatly contribute to the development of the transparent flexible display field, which is a problem. .

In addition, by using the semiconductor properties of the graphene quantum dot pattern prepared according to the present invention, it is possible to help not only the decomposition of water pollutants, which has recently been an issue, but also the development of the photocatalyst field capable of hydrogen production, and in addition, the present invention By using the excellent thermal and electrical conductivity of the graphene quantum dot pattern prepared according to the method, the field of application can be further expanded.

Hereinafter, preferred examples are presented to help the understanding of the present invention. However, the following examples are only provided for easier understanding of the present invention, and the contents of the present invention are not limited by the following examples.

[Example]

Example 1

As shown in the upper figure of FIG. 1, ion beam irradiation was performed to prepare a graphene quantum dot pattern while applying a shadow mask of a grid pattern spaced apart at regular intervals on a silicon substrate. Specifically, a metal catalyst source (containing Fe ions) was implanted into a silicon substrate using an ion beam irradiation device developed by KAERI. At this time, the ion beam irradiation device has a structure in which the ion beam passes through two electromagnets before being irradiated to the sample. 10 ¹⁴ ion/cm ² , but the ion beam irradiation energy was maintained at 35 keV. Thereafter, the substrate onto which the metal catalyst source was injected was first heated to 800° C. under an inert gas atmosphere (flow rate of Ar: 100 sccm) to form metal catalyst particles. Thereafter, the substrate on which the metal catalyst particles are formed is heated a second time to 1000° C. under an inert gas atmosphere (flow rate of Ar: 100 sccm), but graphene over 20 minutes by providing a flow of _{gaseous carbon (flow rate of CH 4 : 25 sccm)} A quantum dot pattern was finally prepared.

Example 2

A graphene quantum dot pattern was finally prepared in the same manner as in Example 1, except that the ion beam irradiation amount was 5 X 10 ¹⁵ ion/cm ^{2 .}

Example 3

As shown in the lower figure of FIG. 1 , a graphene quantum dot pattern was prepared by performing focused ion beam irradiation on a silicon substrate. Specifically, a metal catalyst source (containing Fe ions) was implanted into a silicon substrate using a focused ion beam irradiation device developed by KAERI. At this time, the ion beam irradiation device has a structure in which the ion beam passes through two electromagnets before being irradiated to the sample. 10 ¹⁴ ion/cm ² , but the ion beam irradiation energy was maintained at 35 keV. Thereafter, the substrate onto which the metal catalyst source was injected was first heated to 800° C. under an inert gas atmosphere (flow rate of Ar: 100 sccm) to form metal catalyst particles. Thereafter, the substrate on which the metal catalyst particles are formed is heated a second time to 1000° C. under an inert gas atmosphere (flow rate of Ar: 100 sccm), but graphene over 20 minutes by providing a flow of _{gaseous carbon (flow rate of CH 4 : 25 sccm)} A quantum dot pattern was finally prepared.

2 is an SEM photograph and AFM photograph showing metal catalyst particles formed on a substrate during the manufacturing process of the graphene quantum dot pattern according to Example 1. FIG.

As shown in FIG. 2 , after injecting a metal catalyst source (containing Fe ions) into the substrate through ion beam irradiation, and heating the substrate into which the metal catalyst source is injected to 800° C. under an inert gas atmosphere, small-sized metal catalyst particles was found to be able to form

3 is a TEM photograph and a Raman spectroscopy graph analyzing the characteristics of the graphene quantum dots patterned according to Example 1, and FIG. 4 is a TEM photograph analyzing the characteristics of the graphene quantum dots patterned according to Example 1. and lattic spacing analysis results, and FIG. 5 is an FT-IR graph, EDX graph, and XPS graph analyzing the characteristics of graphene quantum dots patterned according to Example 1.

As shown in FIGS. 3 to 5 , it is confirmed that the graphene quantum dots form a honeycomb lattice having a size of about 3.15 nm to 4.4 nm and a lattice spacing of about 0.225 nm to about 0.336 nm, the size and lattice It can be seen that the interval is controlled to be constant. In addition, it is confirmed that the graphene quantum dots are made of a carbon material.

6 is an SEM photograph, an EDX photograph, and an EDX mapping graph showing whether a graphene quantum dot pattern is selectively formed on a substrate according to Example 1, and FIG. 7 is a graphene quantum dot on a substrate according to Example 2 It is an SEM picture showing whether the pattern was selectively formed.

As shown in FIGS. 6 and 7 , it is confirmed that the graphene quantum dot pattern is selectively formed only in the region irradiated with the ion beam without being covered by the shadow mask of the substrate.

However, from the comparison of the SEM photos shown in FIGS. 6 and 7, since the size of the finally prepared graphene quantum dots increases as the ion beam irradiation amount increases, the ion beam irradiation amount is preferably within ^{5 X 10 14} ion/cm ² can see.

The above description of the present invention is for illustration, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (8)

Board; and
and graphene quantum dots uniformly patterned through ion beam irradiation on the substrate,
The size of the patterned graphene quantum dots is 0.1 nm to 10 nm graphene quantum dot pattern.
delete According to claim 1,
The graphene quantum dots are characterized in that forming a honeycomb lattice having a lattice spacing of 0.1 nm to 0.4 nm, a graphene quantum dot pattern.
(a) implanting a metal catalyst source into a substrate through selective ion beam irradiation;
(b) heating the substrate on which the metal catalyst source is injected to form metal catalyst particles having a size of 0.1 nm to 10 nm; and
(c) removing the metal catalyst by providing a gaseous carbon flow on the substrate on which the metal catalyst particles are formed, and patterning the graphene quantum dots having a size of 0.1 nm to 10 nm Method for producing a graphene quantum dot pattern .
5. The method of claim 4,
The selective ion beam irradiation in step (a) includes: ion beam irradiation using a shadow mask; Or focused ion beam irradiation, characterized in that the graphene quantum dot pattern manufacturing method.
5. The method of claim 4,
The ion beam irradiation amount in step (a) is 1 X 10 ¹³ ion/cm ² to 1 X 10 ¹⁹ ion/cm ^{2 A} method of manufacturing a graphene quantum dot pattern, characterized in that it is.
5. The method of claim 4,
The step (b) is a method for producing a graphene quantum dot pattern, characterized in that it is performed at a temperature of 800 ℃ to 1200 ℃ under an inert gas atmosphere.
5. The method of claim 4,
The flow rate of gaseous carbon in step (c) is 5 sccm to 500 sccm, characterized in that the graphene quantum dot pattern manufacturing method.

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