JP5093791B2 - Method for producing metal oxide structure - Google Patents

Description

The present invention relates to the production how the metal oxide structure.

  As the electron-emitting device, a hot cathode device such as a cathode ray tube has been conventionally used. However, the hot cathode device has a problem of low energy efficiency because electrons are emitted by thermal energy. For this reason, in recent years, there has been an increasing demand for cold cathode devices that do not require thermal energy for electron emission.

  As a cold cathode device, for example, there is a method in which an element having a large number of protrusions such as a Spindt-type cold cathode device is used, and electrons are emitted from the tip of the protrusion by concentrating the electric field on the tip of the protrusion. Has been done.

  In view of the current situation, the present inventors have developed a metal oxide structure having protrusions, which is manufactured using the method described in Patent Document 1, that is, the organometallic pyrolysis method (hereinafter referred to as MOCVD method). Proposed and proposed an electron-emitting device as shown in Patent Documents 2 and 3 using this metal oxide structure.

  However, since the electron-emitting devices described in Patent Documents 2 and 3 have protrusions uniformly on the substrate surface, it is necessary to accurately determine the position of the protrusions on the substrate surface depending on the application. In order to solve this problem, a method described in Patent Document 4, that is, a method of determining a position where a protrusion is present by providing unevenness on the surface of the substrate has been proposed.

No. 99/57345 JP 2000-276999 A JP 2002-274819 A JP 200119410 A

  However, the method described in Patent Document 4 has a problem in that a fine process may be difficult depending on the type of the substrate, and a process different from the process of forming the metal oxide structure is required.

Therefore, the present invention provides a method for producing a metal oxide structure that allows a protrusion to be easily present at a specific position .

  As a result of intensive studies on a structure preferably used as an electron-emitting device, the present inventors have found a method for manufacturing a structure in which protrusions are present at a specific density at a specific position, and complete the present invention. It has come.

  That is, the present invention is as follows.

(1) In order to solve the above-mentioned problem, the first method for producing a metal oxide structure according to the present invention has a circular equivalent diameter of 0.01 to 10,000 μm and a length of 0.1 μm or more on a predetermined surface of a substrate , and the and after the ratio of length to equivalent circle diameter of the cross section is form form a metal oxide having a projection is 0.01 or more, the metal oxide having the protrusion, crimping the pressing member it is, removing at least a portion of said projection, characterized Rukoto the presence of the protrusion to a specific position of the predetermined surface of the substrate.

( 2 ) The method for producing a second metal oxide structure according to the present invention is the method for producing the second metal oxide structure, wherein the pressing member has at least one opening and / or at least one. It is a flat plate having two uneven portions.

( 3 ) The method for producing a third metal oxide structure according to the present invention is the method for producing the first or second metal oxide structure, wherein the oxide reacts with oxygen or water in the air. The metal compound to be formed is used as a raw material, and a metal oxide is formed on the substrate surface by directing the gas and / or fine particles of the metal compound to the surface of the substrate placed in a space where air of a predetermined pressure exists. It is characterized by that.

( 4 ) A fourth metal oxide structure manufacturing method according to the present invention is characterized in that, in the fourth metal oxide structure manufacturing method, the metal oxide is epitaxially grown on the substrate surface. Here, “epitaxial growth” means that a metal oxide having a specific orientation with the substrate is deposited and grown on the substrate surface.

( 1 ) In the manufacturing method of the 1st metal oxide structure, a protrusion can be made to exist in the same specific position repeatedly by a simple method.

( 2 ) In the manufacturing method of the 2nd metal oxide structure, the position where a projection exists can be specified.

( 3 ) In the third method for producing a metal oxide structure, a metal oxide having a specific structure can be produced at a high rate by supplying a high-concentration raw material.

( 4 ) In the fourth method for producing a metal oxide structure, a metal oxide single crystal can be obtained relatively easily.

  Embodiments of metal oxide structure manufacturing method, metal oxide structure manufactured by the manufacturing method, electron-emitting device using the metal oxide structure, and light-emitting device using the electron-emitting device according to the present invention Will be described with reference to the drawings. FIG. 1A is a perspective view of a protrusion. FIG.1 (b) is a protrusion longitudinal cross-sectional view. FIG. 1C is a diagram approximating the outline E0 to a quadratic curve with the point C as the origin. FIG. 4 is a configuration diagram of the light emitting device.

  As shown in FIG. 4, the light emitting device 61 has the electron-emitting device 10. The electron-emitting device 10 uses a metal oxide structure 2 formed on a substrate 11. The metal oxide structure 2 has a metal oxide on the substrate 11. The metal oxide has a plurality of protrusions 12 (see FIG. 1) on a predetermined surface thereof.

  The circular equivalent diameter (hereinafter sometimes simply referred to as a circular equivalent diameter) of the cross section of the protrusion 12 (the cross section at the center point in the length direction of the needle-like body) is 10,000 μm or less. The circle-equivalent diameter is, for example, a value obtained by doubling the square root of the value obtained by dividing the cross-sectional area of the protrusion measured by a conventionally known method using image analysis by the circumference ratio π. When the circular equivalent diameter of the cross section of the protrusion 12 is 10000 μm or less, the function as an electron-emitting device can be sufficiently obtained. The smaller the circle-equivalent diameter of the cross-section of the protrusion 12, the better. A preferable range of the circle-converted diameter of the cross section of the protrusion 12 is 0.01 μm or more and 100 μm or less, and a more preferable range is 0.01 μm or more and 10 μm or less.

  The length of the protrusion 12 is 0.1 μm or more from the viewpoint that the function as the electron-emitting device 10 can be sufficiently obtained. From the viewpoint of the mechanical strength of the protrusion, it is preferably 10,000 μm or less. A more preferable range of the length of the protrusion is 0.5 μm or more and 1000 μm or less, and a more preferable range is 1 μm or more and 500 μm or less.

  The ratio of the length (aspect ratio) of the cross section of the protrusion 12 to the circle-converted diameter is 0.01 or more. From the viewpoint of modification during use, it is preferably 500 or less. If the aspect ratio is within this range, the effect as an electron emitter can be sufficiently obtained.

  When there are a plurality of protrusions 12, the ratio (aspect ratio) of the diameter of the protrusion 12 in terms of the circle equivalent diameter and length and the length of the cross section of the protrusion 12 to the circle equivalent diameter (aspect ratio) is calculated as a sum average value. In addition, the sum average value of ratio (aspect ratio) of the length with respect to the circle equivalent diameter of the cross section of the protrusion 12 is defined as the ratio of the sum average length with respect to the sum average circle equivalent diameter.

  The diameter and length of the protrusion 12 in terms of a circle are determined by observation with a scanning electron microscope (SEM) according to the following method. First, a metal oxide sample is cut along a plane extending through the center of the upper surface thereof and parallel to the longitudinal direction of the protrusion 12 to obtain a cross section. With respect to one obtained cross section, a range of 10 μm on each of the left and right sides in the direction perpendicular to the longitudinal direction of the protrusion 12 is observed with an SEM starting from the above-mentioned central portion. Among the projections 12 that can be observed from the cross-section side within the range, the sum average circle of the projections 12 that can be observed without obscuring the field of view of the entire side surfaces of the projection 12 from the cross-section side by other projections. Calculate the converted diameter and the sum average length.

  Prior to the removal of the protrusions 12 to be described later, the arrangement density of the protrusions 12 is 0.01 or more on the substrate surface 10 μm × 10 μm from the viewpoint that the function as the electron-emitting device 10 can be sufficiently obtained. It is preferable. The larger the arrangement density of the protrusions 12 is, the greater the number of sites that emit electrons, which is preferable. However, the upper limit is preferably 10,000 for ease of manufacturing. From the standpoint of both the action as the electron-emitting device 10 and the ease of manufacturing, a more preferable range of the arrangement density of the protrusions 12 per 10 μm × 10 μm of the substrate surface is 0.01 or more and 1000 or less, and a more preferable range is 1 The number is from 500 to 500. As a result, electrons are emitted from a large number of sites, and electrons are easily emitted uniformly over a wide area.

  The central axes O (see FIG. 1A) of the protrusions 12 before removal may be parallel to each other so that the central axes O do not leave protrusions 12 that are not parallel to each other after the protrusions 12 are removed. preferable.

  If the protrusions 12 whose central axes O are not parallel to each other are not left after the protrusions 12 are removed, when the protrusions 12 are used as the electron-emitting devices 10, the emitted electrons are scattered more than necessary. The desired position on the phosphor surface can be emitted. It can be confirmed by SEM that the central axes O of the protrusions 12 are parallel to each other.

  The metal oxide constituting the protrusion 12 is preferably a single crystal from the viewpoint of the resistance value and current loss of the metal oxide itself. A single crystal means a crystal in which all axial directions are aligned. For example, as shown in FIG. 5, it means that all three axes of the x-axis, y-axis, and z-axis are aligned. In FIG. 5, the three directions have been described. Similarly, in the case of the axial orientations in the four directions, a material in which all the axes in the four orientations are aligned is referred to as a single crystal. Whether the metal oxide constituting the protrusion 12 is a single crystal can be confirmed by a generally known method such as an X-ray rocking curve method or a φ-scan method.

  When the protrusion 12 is a metal oxide crystal, it is preferable that the protrusions are parallel to each other and the crystal axes are in the same direction.

  The cross-sectional shape of the protrusion 12 may be any of a circular shape, a substantially circular shape, a polygonal shape, a substantially polygonal shape, and the like. Moreover, although the cross-sectional shape of the protrusion 12 may be the same in the length direction or may change in the middle, it is preferable that the tip is sharpened like a cone apex, for example. Moreover, when the cross-sectional shape of the protrusions 12 changes in the middle, the adjacent protrusions 12 are prevented from contacting each other.

  When the tip of the protrusion 12 before removal is sharpened, the sharpness may be any. The sharpness of the tip of the protrusion 12 is expressed by a radius of curvature calculated by approximating the apex of the convex tip to a quadratic curve within a predetermined range. The radius of curvature indicating the sharpness will be described with reference to FIG.

  As shown in FIG. 1A, the protrusion 12 has a columnar base 12a and a conical tip 12b. The central axis O of the cylinder forming the base portion 12a passes through the apex C of the cone forming the tip portion 12b. FIG. 1B is a cross-sectional view of the projection 12 cut along a plane including the central axis O of the projection 12.

  As shown in FIG. 1B, the outer shape line E0 of the projection 12 is an outer shape in the predetermined range W of the apex portion of the projection 12 whose tip is convex out of the outer shape line E of the projection 12. Is a line. The predetermined range W is a range having a radius of 50 nm from the central axis O of the projection 12 (a range of 100 nm on both sides of the projection 12 in the width direction (the radial direction of the bottom circle of the base portion 12a) around the vertex C of the tip 12b). is there.

As shown in FIG. 1C, the outline E0 is approximated to a quadratic curve with the point C as the origin. The reciprocal (1 / (2a)) of the value obtained by doubling the coefficient a of the quadratic term of the quadratic equation (y = ax ² + bx + c) indicating this quadratic curve is defined as the above-described radius of curvature. It is preferable that the radius of curvature indicating the sharpness is 10 μm or less. Considering the action as the electron-emitting device 10, the smaller the radius of curvature, the more the electric field concentrates at the tip of the protrusion 12 and the field emission characteristics are improved.

  As the metal oxide, the metal species is group 1, group 2 excluding hydrogen, group 13 excluding boron, group 15 excluding nitrogen, phosphorus and arsenic, Po and 3, 4, 5, 6, 7 in the periodic table. , 8, 9, 10, 11, and 12 can be used.

  The metal oxide is also preferably conductive. Here, the conductivity means that the specific resistivity is 10 Ω / m or less. A preferable range of the specific resistivity is 1 Ω / m or less. Thereby, when the metal oxide structure 2 is used as an electric element (electron emitting element 10 described later), conductivity can be imparted without requiring a specific post-treatment.

Further, the number of metals in the metal oxide may be any as long as it is 1 or more. Specific examples of the metal oxide having conductivity include barium titanate, SrTiO ₃ , LiNiO ₃ , ITO (In ₂ O ₃ / SnO ₂ ), KTaO ₃ , NbLiO ₃ , and ZnO doped with Al ₂ O _3. And the like. Particularly preferred is a metal oxide containing Zn and Al. Thereby, a low resistance value can be obtained by a relatively easy manufacturing method.

(Method of removing the protrusion 12)
The metal oxide structure 2 is formed by once forming a metal oxide having protrusions 12 on a predetermined surface and then removing at least a part of the protrusions 12.

  There are a physical method and a chemical method for removing at least a part of the metal oxide protrusions 12. As an example of a physical method, there is a method of removing the protrusion 12 by processing with a laser or the like. Further, there is a method in which at least a part of the protrusions 12 is crushed and removed by pressing a pressing member on the metal oxide having the protrusions 12. Examples of the pressing member include a flat plate having at least one opening and / or at least one concavo-convex portion, a single rod-like object, and the like.

  The flat plate having at least one opening and / or at least one concavo-convex portion is at least partly flat, and the protrusion 12 is removed at the portion of the flat surface to correspond to a portion that is not flat. The protrusion 12 can be left. In addition, the protrusion 12 can be crushed and removed with a single rod-like object, leaving a portion of the protrusion 12 that does not contact the rod-like object.

  For example, as shown in FIG. 3A, the protrusions 12 can be removed with a punching metal 41 having protrusions higher than the protrusions 12 at predetermined intervals. As shown in FIG. 3B, the punching metal 41 is pressure-bonded to the metal oxide having the protrusions 12, and the protrusions 12 on the substrate 11 are crushed by the plane of the tip of the convex portion of the punching metal 41. Then, as shown in FIG. 3C, the protrusion 12 can be removed by separating the punching metal 41 from the metal oxide. At this time, the protrusion 12 of the part which was not crushed remains on the convex part of the punching metal 41. Thereby, a protrusion can be made to exist in the same specific position repeatedly by a simple method.

  At this time, if the crushed protrusion 12 remains on the metal oxide structure 2, the metal oxide structure 2 and the structure including the metal oxide structure 2 are crushed at the plane portion when moved. There is a case where the protrusion 12 that has not been crushed is damaged. In order to avoid this, a method of physically or chemically removing the protrusions to the outside can be used. As an example of a physical method, a flat part of a plate-like object (pressing member), at least a part of which is flat, is applied with an adhesive or a pressure-sensitive adhesive on the projection 12 and pressed on the flat part. There is a method in which the crushed protrusions 12 are attached to the pressing member by the adhesive force or the adhesive force of the adhesive and removed to the outside of the metal oxide structure 2.

  There is also a method of scraping the protrusion 12 with a linear or plate-like object. Further, after applying a suitable mask or protective agent to the portion of the metal oxide structure 2 having the protrusion 12 to be left, ions or the like are applied to the remaining portion (the portion having the protrusion 12 to be removed) which is not masked or the like. There is also a method of removing the projection 12 by a method such as reverse sputtering in which the projection 12 is removed by impact.

  As an example of the chemical method, an appropriate mask or protective agent is applied to the portion of the metal oxide structure 2 having the protrusion 12 to be left, and then the remaining portion that is not masked (the protrusion 12 to be removed is removed). For example, a method of removing the protrusion 12 by treating the portion having the portion with an acid or alkali.

  At this time, the part to be removed in the protrusion 12 to be removed may be the whole protrusion 12 or a part thereof. When a portion of the metal oxide protrusion 12 is removed, the height of the removed portion is not less than 1/4 of the height of the protrusion, and more than a small height of 2 μm or more is removed. This is preferable because the electric field tends to concentrate on the tip of the remaining protrusion without being affected by the treatment.

  In addition, a thin film made of a metal oxide may be formed between the protrusion 12 and the substrate 11. In this case, when the protrusion 12 is removed, the thin film existing between the protrusion 12 and the substrate 11 may be removed or not removed.

(Method for producing metal oxide having protrusions 12)
A preferred method for producing a metal oxide having protrusions 12 uses a metal compound that forms an oxide by reacting with oxygen or water in the air as a raw material, and is a substrate 11 installed in a space where air of a predetermined pressure exists. The metal oxide is grown on the substrate surface by directing the gas and / or fine particles of the metal compound to the surface. Hereinafter, this manufacturing method will be described in detail.

  In this manufacturing method, (1) a step of gasifying and / or atomizing a metal compound as a raw material, and (2) the gasified and / or atomized metal compound in a space where air of a predetermined pressure exists. And (3) a step of causing this metal compound to react with oxygen or water in the air to grow a metal oxide having protrusions 12 on the substrate. The Thus, by supplying a high concentration raw material, a metal oxide having a specific structure can be produced at a high speed.

  As the metal compound that is a raw material, one formed by reacting with oxygen or water in the air is used. Examples of such metal compounds include (1) alkoxides, (2) ligands such as acetylacetone, ethylenediamine, piperidine, piperazine, cyclohexanediamine, tetraazacyclotetradecane, ethylenediaminetetraacetic acid, ethylenebis (guanide), ethylene A complex having one or more selected from bis (salicylamine), tetraethylene glycol, aminoethanol, glycine, triglycine, naphthyridine, phenanthroline, pentanediamine, pyridine, salicylaldehyde, salicylideneamine, porphyrin, thiourea, (3) As a ligand, conjugated groups including carbonyl group, alkyl group, alkenyl group, phenyl or alkylphenyl group, olefin group, aryl group, and cyclobutadiene group. Various organometallic compounds and halogenated compounds having one or more selected from dienyl groups such as diene groups, cyclopentadienyl groups, triene groups, arene groups, cycloheptatrienyl groups and the like. An organometallic compound is mentioned.

  Among these, complexes and alkoxides having acetylacetone as a ligand are more preferably used.

  When the step of (1) is a step of micronizing the metal compound, the metal compound is heated to a temperature at which the vapor pressure is sufficiently high and gasified, and then the vapor of the obtained metal compound is cooled, The metal compound is atomized by spraying the metal compound in a liquid state or grinding the metal compound with a solid body.

  In the step (1), from the viewpoint of the reaction between the metal compound and oxygen or water, it is preferable that oxygen or water is not present in the system or the amount thereof is extremely small. However, when the reaction rate of the metal compound to be used with oxygen and water is extremely slow, oxygen or water may coexist in the system in the step (1).

  In the step (2), only the gas and / or fine particles of the metal compound may be directed to the substrate surface as they are, or the gas and / or fine particles of the metal compound are positively moved using the carrier gas, and the carrier gas. And may be sprayed from the nozzle onto the substrate surface. In this case, the optimum flow rate of the carrier gas varies depending on the temperature of the step (1) and the state of the space where the substrate 11 is installed.

  When the installation space of the substrate 11 is room temperature and normal pressure, the flow rate of the carrier gas is preferably set so that the space volume value is 20 / min or less, and 5 / min or less. Further preferred. Here, the spatial volume value refers to the flow rate R (volume per minute) of the carrier gas and the heating tank 53 (gas carrier is introduced) that gasifies and / or pulverizes the metal compound in the step (1). This corresponds to the ratio (R / V) of the space, see FIG.

  The carrier gas is not particularly limited as long as it does not react with the raw material metal compound. Specific examples include nitrogen gas, inert gases such as helium, neon, and argon, carbon dioxide gas, organic fluorine gas, and organic substances such as heptane and hexane. Among these, an inert gas is preferable from the viewpoint of safety and economy. Nitrogen gas is particularly preferred from the economical aspect.

  When employing a method in which a metal compound is sprayed from a nozzle onto a substrate surface using a carrier gas, it is preferable that the distance between the nozzle outlet and the substrate surface be within a predetermined range. In this range, the long axis of the opening of the air outlet (the length of the long side when the cross section is rectangular, the length of one side when the cross section is square) is L, and the distance between the air outlet and the substrate surface When K is K, the ratio (K / L) is preferably 0.01 or more, and preferably 1 or less from the viewpoint of the efficiency with which the metal compound is converted into a metal oxide. . Further, it is more preferably 0.05 or more and 0.7 or less, and most preferably 0.1 or more and 0.5 or less.

  The pressure in the installation space of the substrate 11 may be under reduced pressure, normal pressure, or increased pressure. From the viewpoint of the growth rate of the oxide single crystal, productivity, and simplicity of equipment, the pressure in the installation space of the substrate 11 is preferably 0.001 to 20 atm, and more preferably 0.1 to 10 atm. The atmospheric pressure is most preferable.

  Examples of the material forming the substrate 11 include a single crystal of a metal oxide such as aluminum oxide, a single crystal of a semiconductor, a ceramic, a metal containing silicon, glass, and plastic. When a glass plate or a plastic plate is used, it is preferable that the surface is oriented. Among these, a substrate material preferably used is a metal containing silicon, a metal oxide, or a semiconductor crystal such as ZnTe, GaP, GaAs, or InP.

  The substrate 11 is preferably substantially flat. More preferably, the substrate 11 is a substantial plane in a direction perpendicular to the growth direction of the protrusions 12. Further, in the case of the substrate 11 having unevenness, it is preferable that the highest portion is substantially flat. In the case of the substrate 11 having a plurality of the highest convex portions, it is preferable to configure substantially the same plane. More preferably, the same plane substantially constituted by the highest portion of the plurality of convex portions constitutes a plane perpendicular to the growth direction of the protrusions.

As the single crystal seed forming the substrate 11, silicon, metal oxides such as aluminum oxide, magnesium oxide, and SrTiO ₃ are particularly preferably used.

  The state of the metal oxide formed on the substrate surface in the step (3) is mainly determined by the substrate temperature and the degree of supersaturation of the metal compound as the raw material.

  The substrate temperature is a factor that determines the diffusion distance of the raw material on the substrate surface, and the number of metal oxide crystals per unit area, that is, the nucleation density is determined by this diffusion distance. In general, when the substrate temperature is high, the nucleation density decreases and the number of metal oxide crystals per unit area decreases. When the substrate temperature is low, the nucleation density increases and the number of metal oxide crystals per unit area increases. Accordingly, the substrate temperature may be set according to the required formation density of the protrusions. The substrate temperature is preferably 0 ° C. or higher and 800 ° C. or lower, more preferably 20 ° C. or higher and 800 ° C. or lower, and further preferably 100 ° C. or higher and 700 ° C. or lower.

  The degree of supersaturation of the metal compound is a factor that determines the crystal habit, and the crystal habit determines the diameter and length of the metal oxide crystal, that is, the aspect ratio. In general, when the degree of supersaturation is low, the metal oxide crystal tends to grow in a horizontal direction rather than a direction perpendicular to the substrate surface, and thus the aspect ratio becomes small. When the degree of supersaturation is high, the metal oxide crystal tends to grow in a direction perpendicular to the direction parallel to the substrate surface, and thus the aspect ratio becomes large.

  In order to set the aspect ratio of the metal oxide crystal to 1 or more, the supersaturation degree is preferably set to 1% or more. The degree of supersaturation is more preferably 10% or more, and further preferably 20% or more. The definition of the degree of supersaturation in this case is [(actual vapor pressure−equilibrium vapor pressure) / equilibrium vapor pressure] × 100.

  In the step (3), the optimum reaction time for causing the metal compound to react with oxygen or water in the air and growing the metal oxide having the protrusions 12 on the substrate 11 depends on the reaction conditions and the raw materials used. Depending on the type of. For example, when zinc acetylacetonate is used as a raw material, it is preferably 10 minutes or longer under normal room temperature and atmospheric pressure. More preferably, it is 30 minutes or more, and most preferably 1 hour or more.

  In the above manufacturing method, the metal oxide is preferably epitaxially grown on the substrate surface. Thereby, a metal oxide single crystal can be obtained relatively easily.

  In order to epitaxially grow the metal oxide on the substrate surface, a method of growing the metal oxide on the single crystal substrate is preferably used. In this case, it is preferable that the lattice constant in the case where the metal oxide becomes a crystal is close to the lattice constant of the single crystal seed used as the substrate. This value is expressed as (lattice constant of the surface where the metal oxide crystal seed formed contacts the substrate) / (lattice constant of the surface where the single crystal seed used as the substrate contacts the metal oxide crystal seed formed). The ratio is preferably 0.8 or more and 1.2 or less. More preferably, it is 0.9 or more and 1.1 or less, and most preferably 0.95 or more and 1.05 or less.

  Whether or not the metal oxide is epitaxially grown on the substrate surface can be confirmed by a normal X-ray diffraction method. In particular, it is preferable to employ a method of observing the in-plane orientation relationship between the substrate 11 and the metal oxide crystal by the φ scan method. It is preferable that the crystal axes of the metal oxide crystals are in the same direction, that is, the crystal axis orientations are aligned. For example, the fluctuation of the crystal axis orientation measured by the X-ray rocking curve method is preferably within 10 degrees, and more preferably within 5 degrees.

  In the metal oxide structure 2, it is preferable to fix the protrusions 12 by filling a portion of the gap between adjacent protrusions 12 on the substrate side with a synthetic resin or an elastomer. Examples of materials that can be used as a material to fill the gap include organic substances such as thermoplastic resins, thermosetting resins, elastomers, and instantaneous adhesives such as cyanoacrylate, inorganic substances such as glass and ceramics, and metals. It is done. Thereby, it can prevent that the protrusion 12 falls down or bends, and can obtain the structure which a protrusion part does not damage easily.

(Electron emitting device, light emitting device)
As shown in FIG. 4, the circuit 60 of the light-emitting device 61 is a circuit using the metal oxide structure 2 in which the protrusions 12 are present at the specific positions described above.

  The circuit 60 includes transparent conductive materials D1 and D2 fixed to glass substrates (containers) G1 and G2, and the transparent conductive material D2 is connected to the transparent conductive material D1 via a DC power supply B. An electron-emitting device 10 is placed on the transparent conductive material D2, and a light emitter H is provided on the lower surface of the transparent conductive material D1. The electron-emitting device 10 includes a substrate 11 and a metal oxide structure 2. A partition 3 made of an insulating material such as polyimide is provided so that a space is formed between the light emitter H and the substrate 11.

  The circuit 60 was put into the vacuum chamber 4. The inside and the outside of the vacuum chamber 4 can be electrically joined by the terminals 6a and 6b. The terminals 6a and 6b are insulated from each other by the insulator 5. The conductive material D1 was electrically connected to the terminal 6a, and the conductive material D2 was electrically connected to the terminal 6b. Furthermore, the anode of the DC power supply B installed outside the vacuum chamber was electrically connected to the terminal 6a and the cathode was electrically connected to the terminal 6b.

  The inside of the vacuum chamber was depressurized to 3.4 × 10 −6 Pa. When a 3 kV potential was applied between the anode and the cathode using a DC power source installed outside the vacuum chamber, a strong electric field was generated at the tip of the protrusion 12 of the metal oxide structure 2, and the protrusion 12 was generated by field emission. Electrons are emitted in the normal direction of the tip of the. Then, the phosphor surface of the light emitter H emits light.

  Since the electric field is more easily concentrated on the tip of the specific protrusion 12, the field emission characteristics can be further improved. Then, by using the metal oxide structure 2 in which the protrusions 12 are present at the specific positions as described above, the electron-emitting device 10 and the light-emitting device 61 with high energy efficiency can be obtained.

  The present invention will be described based on examples. First, as shown in FIG. 2, a metal oxide having a protrusion 12 is formed on one surface of a substrate 11 under predetermined conditions using a manufacturing apparatus 50 for a metal oxide structure 2.

  The manufacturing apparatus 50 includes a supply source 51, a flow meter 52, a heating tank 53, pipes 54 and 55, a substrate stage 56, a liquid nitrogen trap 57, and a blowout port 58. The supply source 51 supplies nitrogen that is a carrier gas. The flow rate of the carrier gas supplied from the supply source 51 is adjusted by the flow meter 52. On the other hand, the metal compound which is a raw material is vaporized in the heating tank 53.

  Then, the carrier gas whose flow rate is adjusted by the flow meter 52 is introduced into the heating tank 53 through the pipe 54. Then, the carrier gas directs the metal compound vaporized in the heating tank 53 toward the substrate 11 through the pipe 55. The substrate 11 is held on the substrate stage 56 by a heated body. A liquid nitrogen trap 57 is provided in the pipe 54, and the liquid nitrogen trap 57 removes water contained in the carrier gas supplied from the supply source 51.

  A blowing port 58 having a predetermined shape is connected to the tip of the pipe 55, and an opening 58 a of the blowing port 58 is a surface on which the gas from the pipe 55 forms a metal oxide having protrusions of the substrate 11. It is formed to be blown out entirely. Further, the pipe 55 and the outlet 58 are heated by a ribbon heater. The substrate stage 56 is arranged such that the distance K between the outlet 58 and the surface of the substrate 11 is 0.6 in the ratio (K / L) to the major axis L of the opening 58a of the outlet.

  The air outlet 58 and the substrate stage 56 were placed in a room temperature laboratory, and the space between the air outlet 58 and the substrate stage 56 was atmospheric pressure. The substrate 11 was formed so that one surface thereof was along the crystal surface (100) of the single crystal Si, and was placed on the substrate stage 56 with this surface facing upward. The substrate 11 was heated to 550 ° C. by the substrate stage 56, and zinc acetylacetonate and aluminum acetylacetonate were put in a heating tank 53 at a weight ratio of 8/2 and heated to 115 ° C.

In this state, nitrogen is supplied from the supply source 51 to the pipe 54 at a rate of 1.2 dm ³ / min, whereby a mixed gas of a metal compound gas and nitrogen gas is supplied from the outlet 58 to the substrate 11 via the pipe 55. Sprayed in between. Thereby, the metal compound which is a raw material reacts with oxygen or water in the air on the surface of the substrate 11 and in the vicinity thereof to become a metal oxide, and this metal oxide grows on the surface of the substrate 11.

  As a result, a metal oxide having a protrusion 12 in which the protrusion 12 extends vertically on one surface of the substrate 11 is obtained. The metal oxide having the protrusions 12 obtained in this way has a length of the protrusion 12 of 20 μm and a circular equivalent diameter of the cross section of the protrusion 12 when the mixed gas spraying time is 90 minutes. The ratio of the length to the circular equivalent diameter of the cross section of 7 μm was 12.

  The metal oxide having the protrusions 12 thus obtained is taken out together with the substrate 11, and a metal plate (pressing member) in which round holes with a diameter of 0.5 mm are arranged in a grid pattern at a pitch of 1 mm on the surface where the metal oxide is present. The protrusions 12 existing in portions other than the round holes were crushed by pressure bonding. After the metal plate is released, the protrusion 12 is crushed and whitened at the portion where the metal oxide on the substrate 11 is in contact with the metal plate. When this was observed with a laser microscope, the pressed protrusion 12 was scattered in the whitened portion, and the protrusion 12 remained upright in the other portions. By this method, the protrusion 12 can be present at a specific position.

  According to the manufacturing method of the present invention, a metal oxide structure having protrusions at a specific position is obtained, and further, an electron-emitting device with high energy efficiency is provided by using the metal oxide structure manufactured by this method. can do.

It is explanatory drawing of the protrusion of the metal oxide structure concerning this embodiment. It is a block diagram of the manufacturing apparatus which manufactures the metal oxide which has a protrusion. It is explanatory drawing of the removal method of a protrusion. It is a block diagram of a light-emitting device. It is explanatory drawing of the crystal axis direction of a protrusion.

Explanation of symbols

B ... DC power source C ... Vertices D1, D2 ... Transparent conductive materials E, E0 ... Outlines G1, G2 ... Glass substrate H ... Luminescent body O ... Central axis W ... Predetermined range 2 ... Metal oxide structure 3 ... Partition 4 ... Vacuum chamber 5 ... Insulator 6a ... Terminal 6b ... Terminal 10 ... Electron emitter 11 ... Substrate 12 ... Projection 12a ... Base 12b ... Tip 41 ... Punching metal 50 ... Manufacturing device 51 ... Supply source 52 ... Flow meter 53 ... Heating Tank 54, 55 ... Pipe 56 ... Substrate stage 57 ... Liquid nitrogen trap 58 ... Blowout port 58a ... Opening 60 ... Circuit 61 ... Light emitting device

Claims (4)

Metal oxide having protrusions having a circular equivalent diameter of 0.01 to 10,000 μm and a length of 0.1 μm or more on a predetermined surface of the substrate , and a ratio of the length to the circular equivalent diameter of the cross section being 0.01 or more. after form shaped objects, the metal oxide having the projections, by crimping the pressing member, and removing at least a portion of said projections, said the specific position of the predetermined surface of the substrate method for producing a metal oxide structure, wherein Rukoto the presence of projections. 2. The method for producing a metal oxide structure according to claim 1, wherein the pressing member is a flat plate having at least one opening and / or at least one uneven portion. A metal compound that forms an oxide by reacting with oxygen or water in the air is used as a raw material, and the gas and / or fine particles of the metal compound are directed to the surface of a substrate placed in a space where air of a predetermined pressure exists. 2. The method for producing a metal oxide structure according to claim 1, wherein a metal oxide is formed on the substrate surface. 4. The method for producing a metal oxide structure according to claim 3, wherein the metal oxide is epitaxially grown on the substrate surface.