KR101151409B1 - Method of fabricating emitter using carbon nanotube and emitter fabricated using the same - Google Patents

Abstract

PURPOSE: An emitter and a manufacturing method thereof are provided to improve adhesive force by mixing carbon nanotubes of different diameter and to improve durability of an emitter tip at the high voltage. CONSTITUTION: A carbon nano tube layer for emission is formed in a membrane including a plurality of pores. The carbon nano tube layer for emission is formed by filtering a carbon nanotube solution for emission in a vacuum(S120). A carbon nano tube layer for support is formed by filtering a carbon nanotube solution for support in the vacuum to the membrane in which the carbon nano tube layer for emission is formed(S140). The membrane is eliminated from the carbon nano tube layer for emission and the carbon nano tube layer for support(S150). The diameter of the carbon nano tube layer for emission and the carbon nano tube layer for support is different.

Description

METHODS OF FABRICATING EMITTER USING CARBON NANOTUBE AND EMITTER FABRICATED USING THE SAME

The present invention relates to a method for manufacturing an emitter for field emission using carbon nanotubes, and more particularly, to a method for manufacturing an emitter for field emission using a plurality of carbon nanotubes having different diameters. will be.

Carbon nanotubes (CNTs) are attracting attention as emitter materials because of their nanometer-sized radius of curvature at the tips, high aspect ratios, and excellent mechanical, thermal, and chemical properties. One of the materials.

CNTs require high currents in small areas such as high-resolution X-ray tubes and microwave amplifiers, as well as field emission emitters in large area devices such as backlight units (BLUs), surface light sources, and field emission displays (FEDs) in liquid crystal displays (LCDs). A lot of research is being conducted on field emission emitter materials.

However, when operating a CNT emitter at a high current, various problems occur. In particular, emitter damage due to Joule heating, electrostatic interaction, etc. is the biggest problem.

Therefore, in order to solve the problem of damage caused by high current emission, CNT emitter should have the required characteristics such as excellent material, morphological crystallinity, low gas emission rate, optimized distribution density and aspect ratio, height uniformity, and strong adhesion to the substrate. do.

Methods of manufacturing a CNT emitter include vertical growth using CVD, screen printing, spray spraying, vacuum filtration and electrophoresis.

Among these methods, the vacuum filtration method is simple because it is based on a solution in which a surfactant and CNT are dispersed in a solvent. Since the organic matter is removed by calcination and only CNTs are left, there is little gas emission during field emission. In addition, the pore size and distribution of the membrane can be adjusted to optimize the formation of the emitter.

However, although the vacuum filtration method is more suitable for the production of a small area CNT emitter rather than a large area, there are few studies on applications requiring high electric field emission in a small area.

One embodiment of the present invention is a method of producing a CNT emitter by vacuum filtration of different types of carbon nanotube (CNT) dispersion solution using a polymer membrane and a metal mesh (mesh) and a CNT emitter prepared by the method To provide.

In addition, an embodiment of the present invention is to provide a CNT emitter in which the multi-walled CNT having a thin diameter and excellent crystallinity forms an emission layer, and the multi-walled CNT having a large diameter supports the emission layer.

In addition, according to one embodiment of the present invention, when the release layer formed in the form of a film on the membrane is separated from the membrane, the CNT emitter may be separated while maintaining the shape of the tip of the emitter formed in the pores of the membrane intact. To provide a method.

In addition, an embodiment of the present invention to provide a method for manufacturing a CNT emitter that can prevent the breakage of the CNT emitter using a metal mesh and to fix the CNT to improve the durability of the emitter tip at a high voltage do.

As a technical means for achieving the above-described technical problem, the first aspect of the present invention (a) is discharged by vacuum filtration of carbon nanotube (CNT) solution for release in a membrane (membrane) comprising a plurality of pores Forming a carbon nanotube layer for the support, (b) the support carbon nanotubes by vacuum filtration of the support carbon nanotube solution on the membrane formed with the carbon nanotube layer for release by vacuum filtration of the carbon nanotube solution for release Forming a layer and (c) removing the membrane from the formed release carbon nanotube layer and the support carbon nanotube layer, the diameter of the release carbon nanotubes and the support carbon nanotubes. The diameters of the tubes are different from each other, and the carbon nanotubes for release are inserted into the plurality of pores to form an emitter tip. Using can provide a method for producing an emitter.

In a first aspect of the invention, the step (a) comprises (a1) placing a metal mesh on the membrane, (a2) placing the carbon nanotube layer on the membrane in which the metal mesh is located; It may comprise the step of forming.

Further, in the first aspect of the present invention, the support carbon nanotubes and the metal mesh may form an emitter body.

Further, in a first aspect of the present invention, the step (c) comprises (c1) shrinking the membrane and (c2) from the releasing carbon nanotube layer and the supporting carbon nanotube layer having the contracted membrane formed. It may include the step of removing.

In addition, in the first aspect of the present invention, the carbon nanotube solution for release comprises carbon nanotubes for discharge and sodium dodecyl sulfate (SDS), and the step (a) is (a3) the carbon nanotubes for release formed It may include the step of removing sodium dodecyl sulfate (SDS) contained in the layer through distilled water.

In addition, in the first aspect of the present invention, the support carbon nanotube solution includes support carbon nanotubes and SDS (Sodium dodecyl sulfate), and the step (c) is (c3) the carbon nanotubes for the release formed It may include the step of removing the sodium dodecyl sulfate (SDS) contained in the layer or support carbon nanotube layer through heat treatment.

In addition, in the first aspect of the present invention, the diameter of the carbon nanotubes for release may be smaller than the diameter of the support carbon nanotubes.

In addition, the second aspect of the present invention is (a) placing a metal mesh on a membrane (membrane) comprising a plurality of pores, (b) carbon nanotubes for emission in the membrane where the metal mesh is located (carbon nanotube, CNT) vacuum filtration of the solution to form a carbon nanotube layer for release, (c) carbon for support on the membrane formed with a carbon nanotube layer for release by vacuum filtration of the carbon nanotube solution for release Vacuum filtration of the nanotube solution to form a support carbon nanotube layer and (d) shrinking the membrane and removing the contracted membrane from the formed carbon nanotube layer and the support carbon nanotube layer. Produced through the process, the diameter of the carbon nanotubes for the release and the diameter of the support carbon nanotubes are different from each other, the carbon nanotubes for the release A carbon nanotube emitter can be provided that is inserted into a plurality of pores to form an emitter tip.

In addition, a third aspect of the present invention includes an emitter body including a support carbon nanotube and an emitter tip coupled to the emitter body and comprising an emission carbon nanotube, The diameter of the support carbon nanotubes and the diameter of the carbon nanotubes for release may provide a carbon nanotube emitter that is different from each other.

In a third aspect of the invention, it may further comprise a metal portion located between the emitter body and the emitter tip.

According to the above-described problem solving means of the present invention, by combining the carbon nanotubes of different diameters, it is possible to manufacture a carbon nanotube (CNT) emitter with improved adhesion at high voltage.

In addition, according to the above-described problem solving means of the present invention, by using a metal mesh (mesh) as a fixed frame having a larger tip (tip) and the self-patterning in the shape of the metal mesh to emitter excellent in electric field enhancement The metal mesh and the CNT make an electrical communication, which acts as an electrode, thereby facilitating current transfer to the emitter, thereby producing an emitter having a small operating electric field and a large field strengthening factor. have.

In addition, according to the aforementioned problem solving means of the present invention, by using a metal mesh it is possible to prevent the breakage of the CNT emitter and to fix the CNT to improve the durability of the emitter tip at a high voltage.

In addition, according to the above-described problem solving means of the present invention, by using the CNTs of different diameters, the small diameter of the discharge CNT forms the tip of the emitter, the relatively large diameter of the support CNT serves as a filler (filler) May be performed to provide an emitter having improved field emission characteristics.

In addition, according to the above-described problem solving means of the present invention, since the emitter is manufactured on the basis of the solution, the manufacturing process is simple and can be manufactured at a low process cost in terms of economics, the manufactured emitter has excellent field emission characteristics in a small area When the device and the application can be stable reliability.

1 is a flow chart showing the flow of an emitter manufacturing method using carbon nanotubes of different diameters according to an embodiment of the present invention,
2a to 2d is a step-by-step view showing an emitter manufacturing method using carbon nanotubes of different diameters according to an embodiment of the present invention,
3 is a view showing the characteristics of the carbon nanotubes used for the emitter manufacturing according to an embodiment of the present invention,
4 is a view showing the characteristics of an emitter manufactured using a metal mesh and an emitter manufactured using a metal mesh according to an embodiment of the present invention;
FIG. 5 is a diagram illustrating the shape and field emission characteristics of an emitter manufactured using two carbon nanotubes having different diameters and one carbon nanotube according to an embodiment of the present invention. ,
6 is a view showing the characteristics according to the pore size of the membrane of the emitter prepared according to an embodiment of the present invention,
7 illustrates the life of an emitter made in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION 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. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between . In addition, when a part is said to "include" a certain component, which means that it may further include other components, except to exclude other components unless otherwise stated.

1 is a flow chart showing the flow of an emitter manufacturing method using carbon nanotubes of different diameters according to an embodiment of the present invention.

In step S110, a metal mesh is positioned on the polymer membrane. The polymer membrane may comprise a number of pores, for example, a mixed cellulose ester (MCE) membrane with pore sizes of 1, 3 and 5 μm, and a polyvinyl difluoride (PVDF) membrane with a pore size of 0.45 μm. This can be used.

In addition, a metal mesh of # 500 of stainless 304 material having an opening area of 28 × 28 μm ² and a thickness of 60 μm may be used.

In step S120, the carbon nanotube (CNT) solution for emission is vacuum filtered to the polymer membrane where the metal mesh is located. The release CNT solution may be prepared by dispersing the release CNT in distilled water in which SDS (Sodium dodecyl sulfate) is dissolved in a horn-type sonicator.

In step S130, the SDS in the CNT layer for vacuum filtration discharged in step S120 is removed using distilled water or the like.

In step S140, the release CNT solution is vacuum filtered in step S120 to vacuum filter the supporting CNT solution against the polymer membrane on which the release CNT layer is formed.

The support CNT solution may be prepared by dispersing the support CNT in a distilled water in which SDS (Sodium dodecyl sulfate) is dissolved in a horn-type sonicator.

In step S150, the release CNT layer and the support CNT layer formed by vacuum filtration performed in steps S120 and S140 are separated from the polymer membrane by drying.

That is, when the releasing CNT solution and the supporting CNT solution are vacuum filtered and then dried at a constant temperature, for example at about 70 ° C., the polymer membrane is fixed by the metal mesh, whereas the polymer membrane shrinks in the longitudinal direction by drying. The CNT layer does not shrink, thereby allowing the CNT layer to separate from the polymer membrane.

As such, when the CNT layer is separated from the polymer membrane, the CNT formed by being sucked into the pores of the polymer membrane by vacuum filtration can maintain a vertically developed bundle form, which is further separated after the separation from the membrane. Without the tip of the CNT emitter can be formed.

In contrast, when the emitter is manufactured using only CNTs of different diameters without using a metal mesh, it is not easy to separate the CNT layer from the membrane since the CNT layer and the polymer membrane shrink together.

For this reason, the membrane should be melted and baked using acetone or the like, and then a tip of the CNT emitter should be formed through a separate process.

In step S160, heat treatment is performed on the CNT layer separated from the polymer membrane to remove residual SDS. Since the SDS is removed at about 300 ° C., the residual SDS can be removed by heat treatment at 350 ° C.

As such, by removing the residual SDS, a CNT emitter comprising a CNT emitter tip can be produced.

2A through 2D are diagrams illustrating a method of manufacturing an emitter using carbon nanotubes having different diameters according to one embodiment of the present invention.

The metal mesh 120 is positioned on the polymer membrane 110, and the CNT solution for release is vacuum filtered with respect to the polymer membrane 110 and the metal mesh 120 to form the release CNT layer 130.

The emission CNT layer 130 may be positioned not only between the polymer membrane 110 and the metal mesh 120 but also between holes formed in the metal mesh 120.

In addition, the release CNT layer 130 may include a tip portion formed by vacuum filtration of the release CNT solution in the pores formed in the polymer membrane 110.

The support CNT solution is vacuum filtered to the polymer membrane 110 on which the release CNT layer 130 is formed, thereby forming the support CNT layer 140.

The support CNT layer 140 may be coupled to contact with the emission CNT layer 130 through holes formed in the metal mesh 120 as well as the metal mesh 120.

After the support CNT layer 140 is formed, the polymer membrane 110 is contracted through a drying process, and the release CNT layer 130 and the support CNT layer 140 are not contracted by the metal mesh 120. .

As the polymer membrane 110 shrinks as described above, the CNT film 160 and the polymer membrane 110 including the emission CNT layer 130, the metal mesh 120, and the support CNT layer 140 may be formed. These are separated from each other, the CNT emitter tip 150 included in the emission CNT layer 130 may also be separated from the polymer membrane (110).

3 is a view showing the characteristics of the carbon nanotubes used for emitter manufacturing according to an embodiment of the present invention.

(A) to (c) of FIG. 3 includes scanning electron microscopy (SEM) and transmission electron microscopy (TEM) photographs of the CNTs for release, and FIGS. Include a TEM picture.

In the Raman spectrum of CNTs, G peaks appearing at about 1582 cm ^-1 by stretching of CC bonds, and impurities and structural defects such as amorphous carbon appear at 1350 cm ^-1 . The crystallinity of the CNTs can be assessed through IG / ID, the intensity ratio of the D peak.

In addition, the crystallinity of the CNT can be evaluated through the oxidation temperature, which is the peak temperature of the differential thermogravimetric (TGT) curve obtained by dividing the thermogravimetric analysis (TGA) curve. The amount of impurities contained in the CNTs is determined by the mass of residues left after burning to high temperature in the TGA.

As shown in FIG. 3, the release CNTs used in one embodiment of the present invention have a high straightness, excellent dispersibility, and a diameter and a length smaller than the support CNTs. In addition, in one embodiment of the present invention, the CNT used as the release CNT has a larger IG / ID value and higher oxidation temperature than the support CNT, which may result in better crystallinity and thermal stability than the support CNT. Can be.

For example, the emitting CNTs are 2-9 nm in diameter, 10-20 μm in length, IG / ID is 2.04, and may have oxidation temperatures and residual masses of 652.9 ° C. and 20 wt.%. .

In addition, the support CNTs have a diameter and length of 12 to 17 nm and 200 μm, IG / ID and oxidation temperatures of 1.07 and 570.1 ° C., respectively, and may have a residual mass of less than about 10 wt.%. Can make

4 is a diagram illustrating the characteristics of an emitter manufactured using a metal mesh and an emitter manufactured without using a metal mesh according to an embodiment of the present invention.

(A) to (c) of FIG. 4 include a SEM photograph taken at an inclination of 30 ° from the cross-sectional area and the cross-sectional area of a CNT emitter manufactured without using a metal mesh, and FIGS. SEM images taken at a 30 ° tilt from the cross-sectional area and cross-sectional area of the CNT emitters fabricated using the mesh.

4 (g) shows a field emission current-voltage curve, and FIG. 4 (h) shows a Fowler-Nordheim (F-N) plot.

When the emitter is manufactured using the emitting CNT and the supporting CNT having the characteristics described above with reference to FIG. 3, the thickness of the manufactured CNT film is different depending on whether a metal mesh is used.

For example, when preparing a CNT emitter using 10 ml of a release CNT solution and a support CNT solution, when a metal mesh is not used, a CNT film is formed to a thickness of about 60 μm, and the surface shrinks due to plasticity. This may cause cracks and the CNT emitter may be broken.

In contrast, when the metal mesh is used under the same conditions, since the metal mesh is positioned in the middle of the CNT layer, the thickness of the CNT film is 94.8 μm, and since the surface crack does not occur even after firing, it may be more robust.

In addition, as shown in (a) of FIG. 4, the surface of the CNT emitter manufactured without using the metal mesh is hardly formed after the activation of the CNT emitter, while using the metal mesh. The manufactured CNT emitters have well developed CNT emitter tips. As such, when the metal mesh is used, the formation of the CNT emitter tip using the pores of the polymer membrane may be easy.

4 (g) and (h) show the results of measuring the field emission characteristics of the CNT emitter manufactured using the metal mesh and the CNT emitter manufactured without using the metal mesh according to one embodiment of the present invention. Illustrated.

Before and after activation without a metal mesh, a turn-on field that emits 1 μA and a turn-on field that emits 1 μA with a metal mesh Respectively about 1.76, 0.71, and 0.59 V / μm.

In addition, current densities before and after activation without metal mesh at an electric field of about 4 V / μm and current densities for CNT emitters fabricated using metal mesh were about 18.5 and 148.6 mA /, respectively. cm ² and 190.9 mA / cm ² .

4 (h) may be obtained by applying the Fowler-Nordheim (F-N) equations of Equations 1 and 2 below to the field emission I-V curve.

In Equations 1 to 3, φ is a work function (4.61 eV), B is a constant, and b is a slope of a Fowler-Nordheim (F-N) plot. As shown in the graph (h), it can be determined that the measured current is due to field emission from a linear Fowler-Nordheim (FN) plot, and the field strengthening factors calculated using Equations 1 to 3 are 2638, respectively. 10306 and 12351.

The metal mesh inserted into the CNT layer serves to fix the CNT layer so that the CNT layer separates well from the membrane during drying, and vertically form the CNT emitter tip by the pores included in the membrane.

Therefore, the emitter manufactured using the metal mesh according to an embodiment of the present invention has excellent field emission characteristics compared to the emitter manufactured without using the metal mesh.

That is, by manufacturing the emitter using the metal mesh, the metal mesh and the CNT is in electrical communication to act as an electrode, which facilitates the transfer of current to the emitter, resulting in a small operating electric field and a large field strengthening factor. Emitters with values can be made.

FIG. 5 is a diagram illustrating the shape and field emission characteristics of an emitter manufactured using two carbon nanotubes having different diameters and one carbon nanotube according to an embodiment of the present invention. to be.

(A) to (c) of FIG. 5 include SEM images of CNT emitters prepared using only CNTs for release, and FIGS. 5 (d) to (f) show CNTs prepared using only supporting CNTs. And SEM images of FIGS. 5 (g) to (i) include SEM images of CNT emitters prepared using both release CNTs and support CNTs.

As shown in (a) of FIG. 5, in the case of using only the release CNT, a hole exists between the protrusion and the valley portion in the shape of the metal mesh, and the empty space is a CNT because the release CNT is thin and easy to separate. The cohesion between is weak compared to the supporting CNTs, resulting in the release of the CNTs not completely applied on the metal mesh.

In contrast, as shown in (d) of FIG. 5, when only the support CNT is used, the support CNTs have a large diameter and are entangled with each other. There is no presence and there is almost no difference in thickness between the protrusions and valleys.

In addition, as shown in (g) of FIG. 5, when both the release CNT and the support CNT are used, the thickness difference between the protrusion and the valley portion is larger than the thickness difference when only the support CNT is used, but only the release CNT. It is applied to the metal mesh with less empty space than the thickness difference in use. Therefore, both the releasing CNT and the supporting CNT can be used to allow the releasing CNT and the supporting CNT to apply the metal mesh without gaps.

5 (b), (c), (e), (f), (h) and (i) include the shape of the emitter tip included in the emitter.

The release CNTs are short in length and excellent in straightness, and therefore less likely to be entangled with each other, while the supporting CNTs are long and tend to be easily entangled with each other.

Accordingly, the height of the CNT emitter tip formed by the pores of the membrane, contained in the emitter made of only CNTs for release, as shown in FIGS. 5 (b), (c), (e) and (f) On the other hand, the height of the CNT emitter tip contained in the emitter made of only the supporting CNT is relatively high.

In this case, as shown in (h) and (i) of FIG. 5, the CNT emitter tip prepared using both the release CNT and the support CNT is similar to the CNT emitter tip prepared using only the release CNT. Form and distribution.

That is, the release CNT determines the shape and distribution of the tip that determines the emission characteristics, and the support CNT serves as a filter to fill the voids and valleys of the metal mesh so that there is no empty space.

5 (j) and 5 (k) are graphs showing field emission curves and Fowler-Nordheim (F-N) plots of the prepared CNT emitters.

A CNT emitter prepared using only the release CNTs shown in FIG. 5 (j), a CNT emitter prepared using only the support CNTs, a CNT emitter prepared using the release CNTs and a support CNT, respectively. In the field emission characteristic, the turn-on fields emitting 1 μA of current are 1.29, 3.06 and 0.59 V / μm, respectively, and the field enhancement factors correspond to 4006, 1171 and 12351 respectively.

CNT emitters manufactured using only support CNTs having a large diameter have relatively low characteristics of a turn-on electric field or electric field strengthening factor because of the small tip size and the thick tip.

In comparison, field emission characteristics of CNT emitters prepared using only CNT emitters having similar shapes in FIGS. 5 (a) to (i), and CNT emitters prepared using both emitting CNTs and supporting CNTs. Is similar.

However, the turn-on electric field of a CNT emitter manufactured using both the emitting CNT and the supporting CNT is smaller, which is because the supporting CNT fills the empty space generated when only the emitting CNT is used. This is because conduction can be made uniform.

Therefore, in the case of a CNT emitter manufactured by using both the emitting CNT and the supporting CNT, the field emission characteristics of the emitting CNT may be further improved by supporting the supporting CNT to maximize the characteristics of the emitting CNT. Can be.

Thus, according to the emitter manufacturing method according to an embodiment of the present invention, the body of the CNT emitter is formed high due to the support CNTs having a relatively large diameter, for the emission smaller than the support CNT thereon The CNT forms a tip of the CNT emitter to effect electron emission.

6 is a view showing the characteristics according to the pore size of the membrane of the emitter prepared according to an embodiment of the present invention.

6 (a) to 6 (c) include SEM images of emitters prepared using a polymer membrane having a pore size of 0.45 μm according to one embodiment of the present invention, and FIGS. f) includes an SEM image of an emitter prepared using a polymer membrane having a pore size of 1 μm according to an embodiment of the present invention, and FIGS. 6 (g) to (i) show an embodiment of the present invention. According to the SEM image of the emitter prepared using a polymer membrane having a pore size of 3μm, Figure 6 (j) to (l) is a polymer having a pore size of 5μm according to an embodiment of the present invention SEM images of emitters prepared using the membrane are included.

Through (a) ~ (l) of Figure 6, it can be seen that the size and shape of the tip of the emitter produced by the pore size of the polymer membrane changes.

That is, in Figure 6 (c), (f), (i) and (l), the larger the pore size of the polymer membrane, the stronger the suction force when vacuum filtration of the release CNT solution, Due to the increase in the amount of release CNT sucked into the pores of the polymer membrane, the size of the emitter tip in the process of separating from the polymer membrane increases the extent that the tip of the emitter forms a mountain-like shape Gets bigger

6 (a), (d), (g), and (j), the smaller the pore size of the polymer membrane, the greater the difference in the thicknesses of the protrusions and valleys of the metal mesh. It can be seen that the suction force is proportional to the pore size.

(M) and (n) of FIG. 6 include field emission curves and Fowler-Nordheim (F-N) curves of emitters made of polymer membranes having pores of different sizes, respectively.

6 (m) and (n), when the pore size of the polymer membrane is 0.45 μm, 1 μm, 3 μm and 5 μm, the turn-on electric field emitting 1 μA is 2.33, 2.11, 1.17 and 0.59 V / μm and the field enhancement factors are 1748, 1925, 5457 and 12351, respectively.

As such, the force for sucking the CNT solution for release is proportional to the size of the pores of the polymer membrane, thereby determining the amount of the release CNT sucked into the pores of the polymer membrane and the size of the tip of the emitter.

Therefore, the morphological characteristics of the emitter prepared using a polymer membrane having a pore size of 5 μm, that is, the shape and the field emission characteristics are the best.

7 is a diagram illustrating the life of an emitter manufactured according to an embodiment of the present invention.

7 includes a lifetime measurement curve of an emitter manufactured using a polymer membrane having a pore size of 5 μm according to an embodiment of the present invention, and particularly, a cathode plate having a field emission area of 0.5 × 0.5 cm ² ; Alumina sheets were placed between the metal anode plates to maintain a spacing of 340 μm. In a vacuum chamber of approximately 5x10 ^-7 Torr, the cathode was grounded and the anode was a DC voltage (HCN1400-12500). It includes the result of measuring the emission current (HP34401A) while applying the).

As shown in FIG. 7, in an emitter manufactured according to an embodiment of the present invention, starting at an initial current density of 40 mA / cm ² , at a current density of 20 mA / cm ² that is half of the initial current density. It is estimated that it takes about 80 hours to reach. As such, when manufacturing a CNT emitter according to an embodiment of the present invention, the adhesion between the CNT layers having different diameters is improved, and thus the lifespan may be increased compared to the emitter manufactured using the vacuum filtration according to the prior art. Can be.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

110: polymer membrane 120: metal mesh
130: carbon nanotube layer for emission 140: carbon nanotube layer for support
150: Carbon Nanotube Emitter Tips

Claims (15)

In the method of manufacturing an emitter using carbon nanotubes,
(a) vacuum filtration of a solution of carbon nanotubes (CNTs) for release into a membrane comprising a plurality of pores to form a layer of carbon nanotubes for release,
(b) forming a support carbon nanotube layer by vacuum filtration of the support carbon nanotube solution on the membrane in which the carbon nanotube layer for release is formed by vacuum filtration of the carbon nanotube solution for release;
(c) removing the membrane from the formed release carbon nanotube layer and the support carbon nanotube layer.
Including,
The diameter of the carbon nanotubes for the release and the diameter of the support carbon nanotubes are different from each other, the emission carbon nanotubes are inserted into the plurality of pores to form an emitter tip Emmy using carbon nanotubes Manufacturing method.
The method of claim 1,
In step (a),
(a1) placing a metal mesh on the membrane,
(a2) forming the emission carbon nanotube layer on the membrane where the metal mesh is located
Emitter manufacturing method using a carbon nanotube comprising a.
The method of claim 2,
The method of manufacturing an emitter using carbon nanotubes, wherein the supporting carbon nanotubes and the metal mesh form an emitter body.
The method of claim 1,
In step (c),
(c1) shrinking the membrane and
(c2) removing the shrunk membrane from the formed carbon nanotube layer and the support carbon nanotube layer.
Emitter manufacturing method using a carbon nanotube comprising a.
The method of claim 1,
The carbon nanotube solution for emission includes carbon nanotubes and sodium dodecyl sulfate (SDS) for emission,
In step (a),
(a3) removing sodium dodecyl sulfate (SDS) contained in the formed carbon nanotube layer through distilled water;
Emitter manufacturing method using a carbon nanotube comprising a.
The method of claim 5, wherein
The support carbon nanotube solution includes support carbon nanotubes and SDS (Sodium dodecyl sulfate),
In step (c),
(c3) removing SDS (Sodium dodecyl sulfate) contained in the formed carbon nanotube layer or support carbon nanotube layer through heat treatment.
Emitter manufacturing method using a carbon nanotube comprising a.
The method of claim 1,
The diameter of the carbon nanotubes for the release is smaller than the diameter of the support carbon nanotubes emitter manufacturing method using carbon nanotubes.
delete delete delete delete delete For carbon nanotube emitters,
An emitter body comprising support carbon nanotubes and
An emitter tip coupled to the emitter body, the emitter tip comprising carbon nanotubes for emission;
Including,
The diameter of the support carbon nanotubes and the diameter of the carbon nanotubes for the release is different from each other carbon nanotube emitter.
The method of claim 13,
A metal portion located between the emitter body and the emitter tip
Carbon nanotube emitter that further comprises.
The method of claim 13,
The diameter of the carbon nanotubes for emitting carbon nanotube emitter is smaller than the diameter of the support carbon nanotubes.

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