KR102023004B1 - field emission electron source and the manufacturing method thereof - Google Patents

field emission electron source and the manufacturing method thereof Download PDF

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Publication number
KR102023004B1
KR102023004B1 KR1020130016577A KR20130016577A KR102023004B1 KR 102023004 B1 KR102023004 B1 KR 102023004B1 KR 1020130016577 A KR1020130016577 A KR 1020130016577A KR 20130016577 A KR20130016577 A KR 20130016577A KR 102023004 B1 KR102023004 B1 KR 102023004B1
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KR
South Korea
Prior art keywords
carbon nanotubes
base electrode
field emission
metal
electron source
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KR1020130016577A
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Korean (ko)
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KR20140102981A (en
Inventor
강준태
송윤호
정진우
최성열
김재우
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한국전자통신연구원
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/30—Cold cathodes, e.g. field-emissive cathode
    • H01J1/304—Field-emissive cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/022—Manufacture of electrodes or electrode systems of cold cathodes
    • H01J9/025—Manufacture of electrodes or electrode systems of cold cathodes of field emission cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/30—Cold cathodes
    • H01J2201/304—Field emission cathodes
    • H01J2201/30446—Field emission cathodes characterised by the emitter material
    • H01J2201/30449—Metals and metal alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/30—Cold cathodes
    • H01J2201/304—Field emission cathodes
    • H01J2201/30446—Field emission cathodes characterised by the emitter material
    • H01J2201/30453—Carbon types
    • H01J2201/30469—Carbon nanotubes (CNTs)

Abstract

A field emission electron source is provided. The field emission electron source according to the exemplary embodiment of the present invention may include an electrode body, a portion of which is accommodated in the electrode body, and the remaining portion of the field emission electron source is exposed from the electrode body.

Description

Field emission electron source and the manufacturing method

The present invention relates to a field emission electron source and a method of manufacturing the same.

The principle of emitting electrons is largely thermal emission and field emission. Heat dissipation has been applied for a long time, and field emission has been studied in recent years. The principle of field emission is that electrons are emitted from the emitter when an electric field is applied to the conductive emitter under vacuum.

Recently, various nanomaterials have been attracting attention as emitters, but carbon nanotubes (CNT) are the most popular materials. Since carbon nanotubes have a low work function and high aspect ratio geometry, they can easily emit electrons even at low electric fields due to their large field emission factors.

Recently, researches on field emission electron sources using carbon nanotubes in very small areas, such as tips, have been attracting attention for applications in electron emitting devices of ultra-small X-ray tubes, scanning electron microscopes (SEMs), and atomic force microscopes (AFMs).

Korean Patent Publication No. 2012-0054813 (published May 31, 2012) discloses a method for producing a field emission CNT-metal mixed film and an aerosol deposition apparatus.

In the case of a carbon nanotube emitter manufactured by a method of making a field emission electron source using a conventional carbon nanotube, the bonding between the carbon nanotube and the electrode is maintained by van der Waals forces, metal particles, or a thin film of less than ㎚. And outgassing by organic substance occurs. Therefore, in order to obtain a large current at a very small area, CNTs can be desorbed from the electrode, heat generated by the contact resistance between the carbon nanotubes and the electrodes, and outgassing by the organic material to obtain a high current density stably in the carbon nanotube emitter. Can not.

The conventional field emission electron source has a limited field of application because of low field emission efficiency and low emission density. In addition, there is a problem that can not cope with new application technology and industry that requires a very small, large current, such as ultra-small X-ray source, terahertz wave (THz wave) source.

One embodiment of the present invention is to provide a field emission electron source capable of stably obtaining a large current at a very small area.

According to an aspect of the present invention, the field emission electron source may include an electrode body, a portion of which is accommodated inside the electrode body, and the other portion of the carbon nanotube is formed to be exposed from the electrode body.

In this case, the electrode body may be made of any one selected from gold, silver, copper, tungsten and nickel.

According to an aspect of the present invention, there is provided a method for preparing a field emission electron source, including preparing a carbon nanotube suspension, attaching carbon nanotubes to a base electrode, and forming a metal on the surface where the carbon nanotubes are formed on the base electrode. Covering and removing the base electrode and a portion of the metal to expose the carbon nanotubes to the outside.

At this time, in the step of preparing a carbon nanotube suspension, the carbon nanotubes are single-walled carbon nanotubes (SWNT: Double-Walled Carbon Nanotube (DWNT), multilayer carbon nanotubes ( MWNT: Multi-Walled Carbon Nanotube).

At this time, in the step of attaching the carbon nanotubes to the base electrode, the carbon nanotubes may be attached to the base electrode by any one method selected from electrophoresis, spin coating, printing, supporting and spray methods.

In this case, in the step of covering the metal on the surface on which the carbon nanotubes are formed in the base electrode, the metal attached to the base electrode may be the same material as the base electrode.

Since the field emission electron source according to the exemplary embodiment of the present invention has a structure in which carbon nanotubes are firmly fixed to the electrode, there may be almost no outgassing source such as an organic material used in the conventional method of manufacturing the field emission electron source. In addition, the resistance between the carbon nanotubes and the electrode body is significantly reduced compared to the conventional field emission electron source in which carbon nanotubes are formed only on the metal surface, thereby lowering heat generation when a large current flows and stably obtaining a large current at a very small area. . In addition, it can be produced in various structures according to the size and shape of the electrode. In particular, since a field emission electron source with strong adhesion in a very small area can be manufactured, a high current density close to the physical limit can be obtained.

1 is a perspective view schematically showing a field emission electron source according to an embodiment of the present invention;
2 to 4 are perspective views showing various modifications of the field emission electron source shown in FIG. 1.
5 is a flowchart illustrating a method of manufacturing a field emission electron source according to an embodiment of the present invention.
6 to 8 sequentially illustrate the method of manufacturing the field emission electron source shown in FIG.
6 is a perspective view showing a state in which carbon nanotubes are formed on a base electrode.
FIG. 7 is a perspective view illustrating a state in which a surface of carbon nanotubes formed on a base electrode is covered with metal;
8 is a perspective view illustrating a carbon nanotube manufactured by cutting a portion of a base electrode and a metal;

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like elements throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

1 is a perspective view schematically showing a field emission electron source according to an embodiment of the present invention.

Referring to FIG. 1, the field emission electron source 100 according to an embodiment of the present invention may include an electrode body 110 and a carbon nanotube 120.

The electrode body 110 serves to receive the carbon nanotubes 120. When the field emission electron source 100 according to the present invention is applied to a display element, a backlight unit, and an X-ray source for medical imaging, the electrode body 110 may be a cathode electrode. The electrode body 110 may be made of any one selected from gold, silver, copper, tungsten, and nickel.

The carbon nanotubes 120 allow electrons to be emitted when electricity is applied to the electrode body 110. A portion of the carbon nanotubes 120 is accommodated in the electrode body 110, and the remaining portion is formed to be exposed from the electrode body 110. When the field emission electron source 100 according to the present invention is applied to a carbon nanotube field emission display, light is generated when the electrons emitted from the carbon nanotubes 120 are accelerated in a vacuum to collide with a phosphor. This light can be collected to reproduce the image.

According to the configuration of the present invention, the carbon nanotubes 120 that emit electrons have a shape that is tightly fixed by being surrounded by metal as an electrode. As such, since the field emission electron source 100 according to the present invention has a structure in which the carbon nanotubes 120 are firmly fixed to the electrode, there may be no outgassing source such as an organic material used in the conventional field emission electron source manufacturing method. .

In addition, the resistance between the carbon nanotubes 120 and the electrode body 110 is significantly reduced compared to the conventional field emission electron source in which carbon nanotubes are formed only on the metal surface, thereby lowering heat generation when a large current flows, thereby increasing a large amount in a very small area. The current can be obtained stably. In addition, it can be produced in various structures according to the size and shape of the electrode. In particular, since the field emission electron source 100 having strong adhesion in a very small area can be manufactured, a high current density close to the physical limit can be obtained.

Hereinafter, a method of manufacturing a field emission electron source having a structure having the above structure will be described in detail with reference to the accompanying drawings.

5 is a flowchart illustrating a method of manufacturing a field emission electron source according to an embodiment of the present invention.

Referring to FIG. 5, the method of manufacturing a field emission electron source according to an embodiment of the present invention includes preparing a carbon nanotube suspension (s1), attaching carbon nanotubes to a base electrode (s2), and Covering the metal on the surface on which the carbon nanotubes are formed in the base electrode (s3), and removing the portion of the base electrode and the metal to expose the carbon nanotubes to the outside (s4).

Hereinafter, with reference to the drawings, each step of the method for producing a field emission electron source will be described in detail.

First, although not shown, in the step of preparing a carbon nanotube suspension (s1), as an example of a method for producing a carbon nanotube suspension, 100 g of deionized water and purified single layer carbon nanotube (SWNT) ink After mixing 2.5 mg and 10 mg of sodium dodecyl sulfate (SDS), ultrasonic dispersion may be performed for about 1 hour to complete the preparation of the carbon nanotube suspension. Here, as an example of the dispersion method of carbon nanotubes, it may be physically used by ultrasonication, ball milling, centrifugation or chemically using a dispersant.

On the other hand, in the step of preparing the carbon nanotube suspension (s1), the carbon nanotubes are not limited to single-walled carbon nanotubes, double-walled carbon nanotubes (DWNT), multilayer carbon nanotubes (MWNT: Multi-Walled Carbon Nanotube).

However, since the field emission electron source according to the present invention should have a form in which carbon nanotubes are planted inside the electrode body, it is preferable to use a single-walled carbon nanotube having a long length and a diameter to make the structure of the field emission electron source according to the present invention. It may be advantageous to facilitate implementation.

Gold, silver, copper, tungsten, nickel, and the like may be used as the metal, and the metal type may be variously selected according to the field in which the field emission electron source is utilized. However, it is more preferable to select a metal having relatively good conduction characteristics, and if a high temperature process is required for post-treatment in the field emission electron source manufacturing process, it should be selected considering the melting point of the metal material.

6 to 8 are views sequentially illustrating a method of manufacturing the field emission electron source shown in FIG. 1, and FIG. 6 is a perspective view illustrating a state in which carbon nanotubes are formed on a base electrode.

Referring to FIG. 6, in the attaching of the carbon nanotubes 120 to the base electrode 111, the carbon nanotubes may be formed by any one of electrophoresis, spin coating, printing, supporting, and spraying. 120 may be attached to the base electrode 111. As described above, the carbon nanotubes 120 may be attached to the base electrode 111 by one of various methods of attaching the carbon nanotubes 120 to the base electrode 111. The method can be used.

7 is a perspective view illustrating a state in which a surface on which carbon nanotubes are formed in a base electrode is covered with a metal.

Referring to FIG. 7, in the step of covering the metal 112 on the surface where the carbon nanotubes are formed on the base electrode 111 (S3, see FIG. 5), the metal 112 may be attached to the base electrode 111. It may be the same as or different from the base electrode 111. However, the metal 112 attached to the base electrode 111 is made of the same material as the base electrode 111, and although not described above, the method of manufacturing the base electrode 111 and the method of manufacturing the metal 112 are the same. Implementing with may be advantageous in making the structure of the field emission electron source more robust. This is because the metals 112 surrounding the carbon nanotubes under the same conditions all form the same crystal structure. In addition, the carbon nanotubes and the metal 112 may be more closely coupled through heat treatment in a vacuum.

8 is a perspective view illustrating a carbon nanotube manufactured by cutting a part of a base electrode and a metal.

Referring to FIG. 8, in the step of exposing the carbon nanotubes 120 to the outside by removing a portion of the base electrode 111 and the metal 112, the base electrode 111 and the metal are exposed. It is also possible to chemically etch using an axid to remove a portion of 112 and to physically cut. The field emission electron source 100 manufactured by the above method does not need an additional surface treatment process, and the carbon nanotubes 120 are exposed to the outside by removing a portion of the base electrode 111 and the metal 112. At s4 (see FIG. 5), the manufacture of the field emission electron source 100 may be completed.

Although various embodiments of the present invention have been described above, the spirit of the present invention is not limited to the embodiments set forth herein, and those skilled in the art who understand the spirit of the present invention may add components within the same scope. Other embodiments may be easily proposed by changing, deleting, adding, and the like, but this will also fall within the spirit of the present invention.

100: field emission electron source
110: electrode body
111: base electrode
112: metal
120: carbon nanotube

Claims (6)

Base electrode,
A metal attached to one surface of the base electrode, and
It has a predetermined length and diameter, and a plurality of the base electrode and a portion of the metal is removed so that a portion is exposed to the outside of the coupling surface of the base electrode and the metal along a line formed by the combination of the base electrode and the metal A field emission electron source comprising carbon nanotubes. According to claim 1,
And the base electrode and the metal are the same material, and the material is any one selected from gold, silver, copper, tungsten and nickel. Preparing a carbon nanotube suspension,
Attaching a plurality of carbon nanotubes having a predetermined length and diameter to one surface of the base electrode;
Covering a metal having the same size as the entirety of the one surface on which the plurality of carbon nanotubes are formed on the base electrode on the entirety of the one surface on which the plurality of carbon nanotubes are formed; and
Removing a portion of the base electrode and the metal to expose a portion of the plurality of carbon nanotubes to the outside of the bonding surface of the base electrode and the metal along a line formed by the combination of the base electrode and the metal. Field emission electron source manufacturing method. The method of claim 3, wherein
In the step of preparing the carbon nanotube suspension,
The carbon nanotube is any one selected from single-walled carbon nanotubes (SWNT), double-walled carbon nanotubes (DWNT), and multi-walled carbon nanotubes (MWNT). Phosphorus, field emission electron source manufacturing method The method of claim 3, wherein
In the step of attaching the carbon nanotubes to the entire surface of the base electrode,
A method for producing a field emission electron source, attaching the carbon nanotubes to one surface of the base electrode by any one of electrophoresis, spin coating, printing, supporting and spraying. The method of claim 3, wherein
In the step of covering the metal on the entire surface formed with the plurality of carbon nanotubes,
The base electrode and the metal is the same material, and the material is any one selected from gold, silver, copper, tungsten and nickel, field emission electron source manufacturing method.
KR1020130016577A 2013-02-15 2013-02-15 field emission electron source and the manufacturing method thereof KR102023004B1 (en)

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