JP4783239B2 - Electron emitter material and electron emission application device - Google Patents

Description

  The present invention relates to an electron emitter material and an electron emission application device that are excellent in durability and capable of emitting field electrons with a large current.

  As a product to which electron field emission is applied, an X-ray analyzer will be described as an example. X-rays are generated when electrons accelerated by a high voltage collide with a metal target. As an electron emission source of an X-ray analyzer, heat generated by heating a tungsten (W) filament to 1800 to 2000 ° C. The method using electrons is the simplest. However, this method requires a large amount of power to heat the filament, has low thermoelectron generation efficiency, and requires cooling of the periphery of the filament, resulting in a problem that the apparatus configuration must be large.

  In order to avoid such problems, a direct heating type in which a material that generates thermoelectrons at a relatively low temperature such as tungsten oxide is directly coated on the filament to generate heat, or such a material is used as another filament. The use temperature can be reduced to about 800 ° C. by using it as an indirectly heated system that heats at a low temperature, but deterioration of the material becomes a problem in long-term use.

On the other hand, in a method using a sharp filament such as tungsten (W) or lanthanum boride (LaB ₆ ), when a voltage of several kV is applied to this filament, a strong force of about 10 ⁷ V · cm is applied to the tip. An electric field is generated, and electron field emission occurs. However, in this method, it is necessary to maintain an ultrahigh vacuum of 10 ⁻⁸ Pa or more in order to prevent characteristic deterioration due to adsorption of residual gas, and furthermore, only a current of 100 mA or less can obtain stable emission of electrons. There is a problem.

  Hereinafter, an electron emission technique according to a conventional example will be described with reference to FIGS. 9 is a schematic diagram showing the prior art 1, FIG. 10 is a schematic diagram showing the prior art 2, and FIG. 11 is a schematic diagram showing the prior art 3. First, FIG. 9 shows an example of a method of irradiating a target with electrons emitted from an electron source (prior art 1).

According to this prior art 1, electrons 22 generated from a filament type electron source 21 are extracted by a Wehnelt type electrode 23 and irradiated to a target 24. The control of the electron energy changes the acceleration voltage E _a, also changing the filament temperature by the filament voltage E _f in order to control the emission current. The Wehnelt-type electrode potential is normally set to be the same as that of the filament, but the electron beam 22 can be narrowed to some extent by applying a negative potential (see, for example, Patent Document 1).

Figure 10 is conventionally indicates art 2, the grid 25 provided between the Wehnelt type electrode 23 and the target 24, an example of performing current control by changing the grid potential E _g (e.g., see Patent Document 1). However, the methods of the prior art 1 and the prior art 2 have a problem that a current of only about 100 μA can be obtained.

In addition, there is a problem in that field electron emission efficiency is lowered due to oxidation of the filament surface of tungsten (W) or lanthanum boride (LaB ₆ ) or adsorption of gas. Furthermore, since the lifetime of the electron source material itself is short, there is a problem that the electron source material must be frequently cleaned or replaced.

  Diamond has an electronic property called “Negative Electron Affinity (NEA)”, and it is known that electron emission occurs in a low electric field compared to metals. Has been made.

FIG. 11 shows an example of such a micro electron source using diamond (prior art 3). According to this prior art 3, when a negative voltage U is applied from a power source 30 to a diamond film 27 that has been processed to be a cathode, electron emission occurs and an X-ray is generated by colliding with the anode metal 26 (Non-Patent Document 1). reference). With such a structure, minute electron emission can be obtained, but when the voltage U is increased, the current is concentrated on the tip of the diamond projection, and the tip of the projection is destroyed due to heat generation, and the electron emission efficiency is lowered.
JP 2003-36805 A P. Rangsten et al, "Field-emitting structures intended for a miniature X-ray source", Sensors and Actuators, Vol. 82, pp. 24-29 (2000)

  As described in the prior arts 1 to 3 above, until now, most of research and development has been to produce a sharp tip by fine processing using diamond and generate electron emission in a low electric field. However, from an industrial point of view, a power supply of about 10 kV is inexpensive and there is no particular reason for emitting electrons in a low electric field. Rather, it is required that a large current can be drawn by applying a high voltage and that the durability of the electron source is excellent.

  Therefore, finding the new electron source material while making use of the unique physical properties of diamond as described above is the greatest challenge for the time being. The present invention has been made in view of the above problems, and provides an electron emitter material that is excellent in durability and capable of field electron emission of a large current, and an electron emission application device using such an electron emitter material. It is intended to provide.

  In order to achieve the above object, the electron emitter material according to claim 1 of the present invention employs a method in which diamond powder is adsorbed on the surface of a carbon foam and then the chemical vapor deposition (CVD) process is used to form the carbon. It is characterized by growing diamond on the foam.

  The means employed by the electron emitter material according to claim 2 of the present invention is characterized in that in the electron emitter material according to claim 1, the diamond powder is nanodiamond powder.

  The electron emitter material according to claim 3 of the present invention employs the electron emitter material according to claim 1 or 2, wherein the diamond is a continuous diamond film, a discontinuous diamond film or a diamond particle. As fixed on the carbon foam.

  The means employed by the electron emitter material according to claim 4 of the present invention is the emitter material according to claim 3, characterized in that the diamond film thickness or particle diameter is 0.1 to 5 μm. It is.

The means employed by the electron emitter material according to claim 5 of the present invention is the electron emitter material according to any one of claims 1 to 4, wherein the diamond is undoped diamond or boron (B) doped diamond. , Phosphorus (P) -doped diamond or sulfur (S) -doped diamond .

  The means employed by the electron emission application apparatus according to claim 6 of the present invention is that a grid electrode for electron extraction is installed on the front surface of the electron emitter material according to any one of claims 1 to 5. It is a feature.

  The means employed by the electron emission application apparatus according to claim 7 of the present invention is the electron emission application apparatus according to claim 6, wherein the electron extraction grid electrode is any one of a planar shape, a concave shape and a convex shape. It has the shape which combined these, It is characterized by the above-mentioned.

  The means employed by the electron emission application apparatus according to claim 8 of the present invention is the electron emission application apparatus according to claim 6 or 7, wherein the electron emitted from the electron emitter material is collided with a metal, and X-rays are emitted. The X-ray source is generated.

  Means employed by the electron emission application apparatus according to claim 9 of the present invention is the electron emission application apparatus according to claim 6 or 7, wherein the electrons emitted from the electron emitter material collide with the phosphor, and light is emitted. It is characterized by having become a light source to be generated.

  The electron emission application apparatus according to claim 10 of the present invention employs the electron emission application apparatus according to claim 6 or 7, wherein the electrons emitted from the electron emitter material are transmitted through the partition wall and externally provided. The present invention is characterized in that an electron irradiating apparatus for irradiating the surface of the material and performing surface modification is provided.

  According to the electron emitter material of claim 1 of the present invention, diamond powder is adsorbed on the surface of the carbon foam, and then diamond is grown on the carbon foam by chemical vapor deposition (CVD). Therefore, the negative electron affinity (NEA) characteristic of the diamond allows a large current to be drawn by applying a high voltage, and also provides excellent characteristics as an electron source.

  In addition, according to the electron emitter material according to claim 2 of the present invention, since the diamond is a nanodiamond powder, it is easily fixed to the unevenness of the surface at the time of adsorption to the carbon foam and is difficult to peel off. An electron emitter material excellent in efficiency and durability can be obtained.

  Furthermore, according to the electron emitter material according to claim 3 of the present invention, the diamond is fixed on the carbon foam as a continuous diamond film, a discontinuous diamond film or diamond particles. An electron emitter material having excellent electron emission efficiency can be obtained.

  Furthermore, according to the electron emitter material according to claim 4 of the present invention, since the film thickness or particle diameter of the diamond is 0.1 to 5 μm, the carbon foam is excellent in durability and electron emission efficiency. Separation due to the difference in thermal expansion coefficient from the body can be avoided.

According to electron emitter material according to claim 5 of the present invention, the diamond, undoped diamond or boron (B) doped diamond, since phosphorus (P) doped diamond or sulfur (S) doped diamond, the carbon foam Electrons from the body to the diamond film or particles easily move.

  On the other hand, according to the electron emission application apparatus according to claim 6 of the present invention, the grid electrode for electron extraction is installed on the front surface of the electron emitter material according to any one of claims 1 to 5, The emission of electrons from the diamond film or particles is promoted.

  In the electron emission application apparatus according to claim 7 of the present invention, since the electron extraction grid electrode has a planar shape, a concave shape, a convex shape, or a combination of these, it is possible to emit electrons. It is possible to freely control the uniformity, convergence or diffusion.

  Furthermore, in the electron emission application apparatus according to claim 8 of the present invention, since an electron emitted from the electron emitter material collides with a metal to produce an X-ray source, a high current can be obtained. As a result, high-intensity X-rays can be generated.

  Furthermore, according to the electron emission application apparatus according to claim 9 of the present invention, the electron emitted from the electron emitter material collides with the phosphor, and the light source is generated. Can be used as a light source for lighting, fluorescent tubes, displays, and the like.

  According to the electron emission application apparatus of claim 10 of the present invention, an electron irradiation apparatus for performing surface modification by irradiating electrons emitted from the electron emitter material through a partition wall to an external material surface is provided. Therefore, since a high-current electron beam can be taken out, the processing speed of the material surface is increased and the productivity is improved.

Next, an electron emitter material according to an embodiment of the present invention and an electron emission application apparatus using the same will be described below with reference to the accompanying drawings. FIG. 1 is a drawing substitute electron micrograph of a carbon foam according to an embodiment of the present invention, FIG. 2 is a drawing substitute electron micrograph of an electron emitter material according to an embodiment of the present invention, and FIG. 3 is an electron shown in FIG. It is a drawing substitute electron micrograph which expanded the emitter material surface.

  A carbon foam (carbon foam) according to an embodiment of the present invention is composed of a carbon skeleton as shown in FIG. 1, and the pore size can be controlled to the micron order by the manufacturing method. The pore size of the carbon foam shown in FIG. 1 is about 700 μm.

  FIG. 2 shows an electron emitter material according to an embodiment of the present invention, in which nanodiamond powder is adsorbed on the surface of the carbon foam shown in FIG. 1, and subjected to chemical vapor deposition using a diamond CVD apparatus. It was obtained by growing. As shown in FIG. 3, it can be seen that nanodiamonds are fixed as a continuous film or particles on the surface of the carbon foam.

  In order to uniformly adsorb the diamond powder on the surface of the carbon foam, a method of dispersing the diamond powder in the solution and bringing the solution into contact with the surface of the carbon foam is preferable. After maintaining the contact state for a predetermined time, the carbon foam is taken out from the solution, dried, and then subjected to CVD treatment in vacuum.

  The diamond powder generally has an average particle size of about 0.1 μm or more. In contrast, nanodiamond powders having an average particle size of 5 nm are also commercially available. As shown in FIG. 3, the carbon foam surface is coated with diamond in the form of a continuous diamond film, a discontinuous diamond film or diamond particles, and in any case functions as an electron emitter material.

  In particular, a diamond film that is discontinuous to the extent shown in FIG. 3 is more advantageous than a continuous diamond film because peeling due to a difference in thermal expansion coefficient from the carbon foam as a base material can be prevented. The nanodiamond powder can be used as long as its average particle size is smaller than 0.1 μm, but preferably has an average particle size of about 5 nm to 10 nm.

  Further, the film thickness or particle diameter of the diamond is preferably in the range of 0.1 to 5 μm. When the film thickness or particle size is less than 0.1 μm, the effect of diamond coating is small in terms of durability and electron emission efficiency. When the film thickness or particle size exceeds 5 μm, the carbon foam as a base material This is because peeling due to the difference in thermal expansion coefficient from the above becomes remarkable.

  Electron emission from such an electron emitter material made of diamond-coated carbon foam provides a high current for the following reasons. That is, at first, electrons are emitted from a plurality of sites where the electric field concentration is strong in the skeleton structure, but even if some of these sites are damaged and no longer emit electrons, The electric field concentrates and electron emission starts from a new site. In this respect, a carbon foam having a random structure is advantageous. In order to increase the amount of current per unit area, it is preferable that the pore size is 10 to 1000 μm and the porosity (porosity) is 90 to 97%.

  In the skeleton structure constituting the carbon foam, as will be described in detail later, when the voltage is raised, electrons are emitted also from the inside of the skeleton, so that the electron emission current is increased. However, as described above, diamond powder or nanodiamond powder is adsorbed on the surface of a normal carbon plate having no skeleton structure, and the nanodiamond powder is grown by chemical vapor deposition using a diamond CVD apparatus. Even when the electron emitter material is used, if the substrate has a planar structure, electric field concentration does not occur, and a large current during electron emission cannot be obtained.

  In the above, the reason why diamond coating by CVD after diamond powder adsorption is necessary is that the electron emission efficiency is higher from the diamond film than the diamond powder, so the diamond film is formed using the diamond powder as a nucleus. . The electron emission current is reduced only by the adsorption of diamond powder or nanodiamond powder. If diamond powder or nanodiamond powder is not adsorbed, diamond does not grow directly on the carbon foam, so it is necessary to adsorb diamond powder on the carbon foam in advance.

  In the electron emitter material according to the present invention, the diamond coated on the surface of the carbon foam is preferably undoped, boron (B) -doped, phosphorus (P) -doped or sulfur (S) -doped. Boron (B) doped diamond exhibits p-type semiconductor or metallic electrical conduction. And phosphorus (P) and sulfur (S) dope diamond show the electrical conduction of an n-type semiconductor. Therefore, doped diamond tends to move electrons from the carbon foam to the diamond film surface. However, when the applied electric field is a high electric field of about 50 kV / cm, the difference from undoped diamond is small.

Next, an electron emission application apparatus according to an embodiment of the present invention using the electron emitter material as described above will be described below.
An electron emission application apparatus according to an embodiment of the present invention using an electron emitter material made of a carbon foam coated with diamond has an electron extraction grid electrode disposed on the front surface of the electron emitter material to emit electrons. It is composed. If necessary, a known lens mechanism for electron beam convergence can be used. The grid electrode for electron extraction has a planar shape, a concave shape, a convex shape, or a combination thereof according to a necessary emission electron density distribution.

  Further, if a grid electrode for electron extraction is installed on the front surface of the electron emitter material (carbon foam coated with diamond) according to the present invention and electrons emitted from the electronic material collide with the metal, the characteristic X-rays from the metal can be obtained. It is possible to configure an electron emission application device that generates the above. In particular, if a field electron emission material made of the electron emitter material according to the present invention is used, a high current can be obtained, so that high-intensity X-rays can be generated.

  In addition, an electron emission application device is provided in which a grid electrode for electron extraction is installed on the front surface of the electron emitter material, and if electrons emitted from the electronic material collide with the phosphor, light corresponding to the phosphor is generated. It can be used as a light source for lighting, fluorescent tubes, displays, etc.

  In addition, an electron irradiating device can be installed in which a grid electrode for electron extraction is installed on the front surface of the electron emitter material, and electrons emitted from the electronic material are transmitted through the partition walls to irradiate the surface of the external material. It becomes. In this case, by using the field electron emission material made of the electron emitter material according to the present invention, a high-current electron beam can be taken out, so that the processing speed of the material surface is increased and the productivity is improved.

  By the way, when the temperature of the electron emitter material is increased, the amount of electron emission tends to increase. However, since the electron emitter material according to the present invention is carbon, it has excellent heat resistance and can be increased by external heating or self-heating. Is possible. Further, the temperature of the electron beam can be effectively controlled by controlling the temperature.

  Furthermore, in the electron emitter material according to the present invention, since the thickness of the carbon foam can be several mm to several cm, the carbon foam is increased as the voltage between the electron extraction grid electrode is increased. The electron emission starts from a deep position of the electrode, and the higher the voltage is applied, the more the electron emission amount increases more rapidly than the planar electron emitter material.

  Such a situation is schematically shown in FIG. That is, the graph in FIG. 4 shows that when an electron extraction grid electrode 3 is provided on the front surface of the electron emitter material 1 according to the present invention attached to the support 2 and a negative applied voltage 4 is applied, the electron extraction material The distribution of the applied voltage with respect to the position from the grid electrode 3 toward the electron emitter material 1 is shown. In the figure, a straight line indicates a voltage distribution when a high voltage is applied, and a one-dot chain line indicates a voltage distribution when a low voltage is applied.

  In general, the electron emission from the electron emitter material is not manifested unless the electric field strength formed by the applied voltage exceeds a certain value, that is, the electron emission critical electric field or more. In FIG. 4, if the electron emission critical electric field when a low voltage is applied is the electric field strength when the voltage is V1, the electron emission from the electron emitter material 1 is a portion where the electric field strength is stronger than the position 1a, that is, the position. It cannot be released only from the front of 1a.

  On the other hand, when a high voltage is applied, an electron emission critical electric field is obtained when the voltage V2 has the same slope as the voltage distribution slope (electron emission critical electric field) when the voltage V1 is applied. Therefore, the electron emission from the electron emitter material 1 when a high voltage is applied is emitted from the front of the position 1b. That is, as the voltage between the electron extraction grid electrode 3 increases, electron emission from a deep position of the carbon foam starts, and as the high voltage is applied, the electron emission amount from the electron emitter material 1 increases more rapidly. It will increase.

  As described above, the electron emitter material according to the present invention is obtained by growing diamond on the carbon foam by chemical vapor deposition (CVD) after adsorbing diamond powder on the surface of the carbon foam. A high voltage can be applied to draw a large current, and the durability as an electron source is excellent.

  In the electron emission application apparatus according to the present invention, since the electron extraction grid electrode is provided on the front surface of the electron emitter material, the emission of electrons from the diamond film or particles is promoted.

<Example 1>
The carbon foam shown in FIG. 1 has a rectangular shape with a surface of about 4 mm square and a thickness of about 3 mm, porosity (porosity) of 96.5%, pore size of about 500 μm, density of 0.05 g / cm ³ . The body was immersed overnight in an aqueous solution in which 1 g of nanodiamond powder having an average particle size of about 5 nm was suspended in 5 ml of water. This sample was taken out, placed on a substrate support of a microwave CVD apparatus after drying, and diamond was synthesized under the following CVD conditions for 1 hour. As a result, as shown in FIGS. 2 and 3, an electron emitter material coated with diamond almost uniformly both inside and outside the carbon foam was obtained. The particle diameter of diamond varied depending on the location of the carbon foam, but was generally 0.5 to 3 μm.

CVD condition material gas: 0.5% by volume of methane, 99.5% by volume of hydrogen
Gas pressure: 5332 Pa
Gas flow rate: 100cc / min Substrate temperature: 800 ° C
Microwave input: about 400W

<Example 2>
The carbon foam (electron emitter material) coated with diamond prepared in Example 1 was fixed to an aluminum support with carbon tape and placed in a vacuum vessel so that a negative voltage could be applied. A metal mesh was placed at a position about 2 mm away from the electron emitter material, and was set to ground potential. Further, a fluorescent plate was placed at a position about 50 cm away from the electron emitter material at an angle of 45 degrees from the electron traveling direction, and light was emitted when the emitted electrons collided.

  When a voltage of 4 kV was applied to the electron emitter material, it was observed from the window of the vacuum vessel that the fluorescent plate emitted green light due to electron emission. When the applied voltage is about 4 kV, an image that seems to be a skeleton of a carbon foam can be seen on the phosphor plate. However, when the applied voltage is about 5 kV or more, the amount of emitted electrons increases rapidly and the phosphor plate emits light almost uniformly.

  FIG. 5 shows measurement data of the emission current density with respect to the applied voltage. Electron emission starts from an applied voltage of 3.5 kV, and a rise in current density is observed. The current is the total amount of current due to electrons colliding with the grid, electrons colliding with the vacuum vessel wall, and electrons colliding with the fluorescent screen.

<Example 3>
When synthesizing diamond into a carbon foam by the same method as in Example 1, phosphine diluted with diborane (B ₂ H ₆ ) diluted to 500 ppm with hydrogen at 1 cc / min and 500 ppm with hydrogen in the raw material gas ( Boron (B) -doped, phosphorus (P) -doped and sulfur (S) -doped diamond were synthesized by introducing hydrogen sulfide (H ₂ S) diluted with PH ₃ ) to 1 cc / minute and hydrogen diluted to 500 ppm with 1 cc / minute, respectively. did. These samples were subjected to the same experiment as in Example 2 to confirm electron emission.

<Example 4>
Electron emission similar to that of the second embodiment is performed by changing the shape of the grid electrode for electron extraction to a concave grid electrode 3a as shown in FIG. 6A and a convex grid electrode 3b as shown in FIG. 6B. The experiment was conducted. When the same voltage was applied, the emission luminance of the fluorescent plate was stronger when the grid electrode was the concave grid electrode 3a than when the grid electrode was the convex grid electrode 3b. When the grid electrode has a concave shape, as shown in FIG. 6A, the emitted electron beam 5 tends to converge due to the influence of the electric field distribution, whereas the grid electrode has a convex shape. In this case, it is considered that the electron beam 5 tends to diverge as shown in FIG.

<Example 5>
X-ray generation due to electron beam collision was confirmed using an apparatus shown in FIG. 7 that irradiates a target with electrons emitted from an electron source in a vacuum container. A negative potential of 15 kV was applied to the grid electrode 3 by the DC power source 6, the electron beam 5 was emitted from the electron emitter material 1 according to the present invention, and the target metal (Cu) 7 was irradiated. As a result, it was confirmed with a Geiger counter and a radiation badge that X-rays 8 were emitted from the target metal 7.

<Example 6>
When a grid electrode for electron extraction and a fluorescent plate were installed on the front surface of the electron emitter material according to the present invention and a voltage of about 3.5 kV or more was applied to the grid for electron extraction, the fluorescent plate emitted green light. If the material of the fluorescent plate is changed, the color can be freely changed, and if a different fluorescent material is applied to a plurality of regions, it can be used as a display. It was also confirmed that the brightness could be controlled by changing the voltage.

<Example 7>
As schematically shown in FIG. 8, the electron emitter material 1 according to the present invention was sealed in a vacuum container 10, and an electron transmission window 10 a made of a thin film was provided on the front surface of the electron emitter material 1. The vacuum vessel 10 was grounded 11 and a negative potential was applied to the electron emitter material 1. It was confirmed that when 5 kV was applied to the electron extraction grid electrode 3, the electrons 5 were emitted from the partition walls into the atmosphere.

<Comparative Example 1>
Except for not immersing the carbon foam in the suspension water of the diamond powder, the CVD treatment was performed in the same manner as in Example 1, and an attempt was made to grow diamond on the carbon foam. Diamond could not be synthesized. Using the carbon foam subjected to the treatment, electron emission was confirmed by the same method as in Example 2, but the electron emission performance was low.

  As described above, the electron emitter material according to the present invention is obtained by growing diamond on the carbon foam by chemical vapor deposition (CVD) after adsorbing diamond powder on the surface of the carbon foam. A high voltage can be applied to draw a large current, and the durability as an electron source is excellent. Further, since the diamond is fixed on the carbon foam as nanodiamond powder, continuous diamond film, discontinuous diamond film or diamond particles, an electron emitter material having excellent electron emission efficiency can be obtained. .

  On the other hand, in the electron emission application apparatus according to the present invention, since the grid electrode for electron extraction is installed on the front surface of the electron emitter material, the emission of electrons from the diamond film or particles is promoted. In addition, since the grid electrode for electron extraction has a flat shape, a concave shape, a convex shape, or a combination of these shapes, the electron emission can be made uniform, converged, or diffused freely. .

  Furthermore, the electron emission application apparatus according to the present invention is an X-ray source or a light source that emits X-rays or light by colliding electrons emitted from the electron emitter material with a metal or a phosphor. Light corresponding to X-rays or phosphors can be generated. In particular, the latter can be used as a light source for illumination, fluorescent tubes, displays, and the like.

It is a drawing substitute electron micrograph of the carbon foam which concerns on embodiment of this invention. It is a drawing substitute electron micrograph of the electron emitter material which concerns on embodiment of this invention. 3 is a drawing-substituting electron micrograph in which the surface of the electron emitter material shown in FIG. 2 is enlarged. When a grid electrode for electron extraction is provided on the front surface of the electron emitter material according to the present invention and a negative applied voltage is applied, the distribution of the applied voltage to the position in the direction of the electron emitter material from the electron extraction grid electrode is schematically illustrated. FIG. It is measurement data of the emission current density with respect to the applied voltage in Example 2. FIG. 6A is a schematic diagram for explaining Example 4 in which an electron emission experiment was performed by changing the shape of the grid electrode for electron extraction, and FIG. 6A shows the case of the concave grid electrode 3a. Indicates the case of the convex grid electrode 3b. It is a schematic diagram for demonstrating Example 5 which irradiates a target with the electron discharge | released from the electron source in a vacuum vessel. FIG. 10 is a schematic diagram for explaining Example 7 in which electrons emitted from an electron source are emitted from an electron transmission window in a vacuum container. It is a schematic diagram which shows the prior art 1. FIG. It is a schematic diagram which shows the prior art 2. FIG. FIG. 6 is a schematic diagram showing a conventional technique 3.

Explanation of symbols

V1, V2: Voltage equivalent to electron emission critical electric field 1: Electron emitter material, 1a, 1b: Electron emission limit 2: Support base 3: Electron extraction grid electrode, 3a: Concave grid electrode, 3b: Convex grid electrode 4: Negative potential, 5: Electron beam, 6: DC power supply 7: Target, 8: X-ray,
10: Vacuum container, 10a: Electron transmission window 11: Earth

Claims (10)

  An electron emitter material, wherein diamond powder is adsorbed on a surface of a carbon foam, and then diamond is grown on the carbon foam by chemical vapor deposition (CVD).   The electron emitter material according to claim 1, wherein the diamond powder is a nanodiamond powder.   3. The electron emitter material according to claim 1, wherein the diamond is fixed on the carbon foam as a continuous diamond film, a discontinuous diamond film or diamond particles.   4. The electron emitter material according to claim 3, wherein the diamond has a film thickness or particle diameter of 0.1 to 5 [mu] m. The diamond, undoped diamond or boron (B) doped diamond, phosphorous (P) doped diamond or sulfur (S) electrons according to any one of claims 1 to 4, characterized in that a doped diamond, Emitter material.   6. An electron emission application apparatus, wherein an electron extraction grid electrode is provided on a front surface of the electron emitter material according to any one of claims 1 to 5.   7. The electron emission application apparatus according to claim 6, wherein the electron extraction grid electrode has one of a planar shape, a concave shape, and a convex shape or a combination thereof.   The electron emission application apparatus according to claim 6 or 7, wherein an electron emitted from the electron emitter material collides with a metal to form an X-ray source that generates X-rays.   8. The electron emission application apparatus according to claim 6, wherein the electron emission material is used as a light source for causing light emitted from the electron emitter material to collide with a phosphor.   8. The electron emission device according to claim 6, wherein the electron emitted from the electron emitter material is irradiated on a surface of an external material through a partition wall to form an electron irradiation device for surface modification. Applied equipment.

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