JP5211297B2 - Metal nitride manufacturing method - Google Patents

Description

  The present invention relates to a method for producing a metal nitride.

  Since metal nitride generally has the characteristics of high hardness, high melting point, and chemical stability, it is widely put into practical use as a heat-resistant material or a superhard material. Recently, metal nitride has attracted attention as an electronic material. Among these, nitrides of Group III metals have wide gap semiconductor characteristics and are therefore applied to luminescent materials and the like. Gallium nitride is known as a material having a very high light emission efficiency as demonstrated by blue and green light emitting diodes (LEDs) (for example, Japanese Patent No. 2791448 and Japanese Patent No. 2829319). Group III nitride phosphors typified by gallium nitride have an extremely large binding energy compared to ZnS, etc., and are extremely chemically stable. Therefore, they cannot be degraded by high electron beam energy or deep ultraviolet light. There is expected. Furthermore, since this phosphor does not contain harmful elements such as Cd, it is expected to be very useful from the viewpoint of environmental conservation.

As a method for producing a metal nitride, a direct nitridation method for obtaining a nitride by heating a metal powder to a high temperature in an atmosphere containing nitrogen (nitrogen, ammonia, etc.) JP-A-61-83604), and a reduction nitriding method in which a metal oxide is heat-treated in a nitrogen atmosphere in the presence of carbon (for example, JP-A-63-297205). However, in these methods, since nitrogen is taken into the metal powder or metal oxide from the treatment atmosphere, it is difficult to nitride the surface of the metal powder or metal oxide even if the surface is nitrided. Further, the reduction nitriding method has a problem that carbon used as a reducing agent is combined with a metal element to form a carbide, which is easily dissolved in the metal nitride.

  When producing multi-element nitrides, the homogeneity of the starting materials is most important. In order to make the starting material itself uniform, it is desirable to synthesize the starting material from a raw material through a homogeneous state. For example, in the above reduction nitriding method, it is necessary to prepare a multi-element compound having a uniform composition such as a multi-element oxide as a starting material, and useful methods for obtaining the compound include sol-gel method and coprecipitation. It is a liquid phase method using a chemical process represented by the method. However, in these conventional liquid phase methods, even if the raw material solution is uniform, the hydrolysis rate and solubility product differ depending on the type of metal compound. Even if the obtained substance is in the form of fine particles, it becomes non-uniform.

  That is, in the conventional method as described above, no matter how precisely the metal composition ratio or the doping amount of the metal element is controlled, even if the metal composition ratio contained in each particle can be controlled as desired. In principle, it is impossible to obtain a uniform metal nitride even in the metal distribution in the particles.

  The method for producing a metal nitride according to the present invention uses an organometallic chelate complex containing a single metal or an organometallic chelate complex having a uniform composition containing a plurality of metals as a starting material, and this is heated in a nitrogen-containing atmosphere. It has a gist.

  As the organometallic chelate complex containing a single metal used in carrying out the method, crystallization from an aqueous solution of an organometallic chelate complex obtained by reacting the metal or a metal compound thereof with an organic chelating agent. It is preferable to use the organic metal chelate complex crystals obtained by spray drying the organic metal chelate complex crystals or the organic metal chelate complex aqueous solution. In addition, as an organometallic chelate complex having a uniform composition containing a plurality of metals, a metal simple substance of the constituent metal element or a metal compound thereof and an organic chelating agent, and / or an organometallic chelate complex of the constituent metal element, a predetermined metal It is preferable to use an organometallic chelate complex powder obtained by spray-drying an organometallic chelate complex aqueous solution prepared by mixing so as to have a composition.

  As the organic chelating agent, at least one selected from organic acid chelating agents and aminocarboxylic acid chelating agents can be used. As the organic acid chelating agent, hydroxyl carboxylic acid and / or its amine salt is preferably used. Particularly preferred as the aminocarboxylic acid-based chelating agent are nitrilotriacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, and amine salts thereof, which can be used alone or optionally as required. It is also possible to use two or more in combination.

  The nitrogen-containing atmosphere employed when carrying out the present invention is preferably an atmosphere containing at least one of nitrogen, dinitrogen monoxide and ammonia.

  Examples of the metal nitride serving as the target substance of the present invention include nitrides of alkaline earth metals, transition metals, rare earth metals, and metalloids. Among these, a particularly high practicality is one of BN, AlN, GaN, InN, and TiN, or a mixed crystal containing two or more thereof.

  When producing a mixed crystal containing any one of BN, AlN, GaN, TiN or two or more thereof as the metal nitride, the heating temperature of the heat treatment is preferably 500 to 1600 ° C, more preferably It is good to set it as the range of 900-1500 degreeC. When producing InN or a mixed crystal containing the same, the heating temperature of the heat treatment should be 400 to 900 ° C., more preferably 450 to 800 ° C.

The metal nitride serving as a target substance of the present invention includes a composition formula In _x Ga _y Al _z N or In _x Ga _y Al _z N: M (where x + y + z = 1, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1). , 0 ≦ z ≦ 1, and M represents a metal or a semimetal).

  When manufacturing the said group III nitride fluorescent substance, the preferable heating temperature of the said heat processing is the range of 400-1600 degreeC.

  Preferable as M in the composition formula is magnesium, zinc, silicon, germanium or a rare earth element. Particularly preferred as the relationship of x, y, z in the composition formula is y ≧ 0.7 and x + z ≦ 0.3, or y = 1 and x = z = 0.

3 is an X-ray diffraction chart of GaN obtained in Reference Example 1. FIG. 4 is an X-ray diffraction chart of TiN obtained in Reference Example 2. 6 is an X-ray diffraction chart of InN obtained in Example 3. FIG. 6 is an X-ray diffraction chart of Zn or Mg-doped GaN obtained in Reference Examples 4 and 5. FIG. It is an emission spectrum figure of the nitride type fluorescent substance (GaN: Zn, GaN: Mg, GaN: Tb) powder obtained in Reference Examples 4-6. 10 is an X-ray diffraction chart of the nitride-based phosphor (GaN: Zn, GaN: Mg, GaN: Tb) powder obtained in Reference Example 6. FIG.

  First, the outline of the method for producing the metal nitride of the present invention will be described.

  The metal nitride which is the target substance of the present invention is an alkaline earth metal, transition metal, rare earth metal or semimetal nitride. For example, alkaline earth metals such as Mg and Ca; transition metals such as Ti, Zr, V, Nb, Ta, Cr, Fe, Cu, and Zn; Group III metals such as B, Al, Ga, and In; Si, Ge And nitrides such as semimetals. Among these, BN, AlN, GaN, InN, TiN, and mixed crystals containing two or more of these are particularly useful, and these are extremely useful as, for example, phosphors, sintering materials, and pigments. It is.

  The present invention is characterized in that an organometallic chelate complex is used as a raw material when producing these metal nitrides. A metal nitride can be obtained by heat-treating the organometallic chelate complex in a nitrogen-containing atmosphere.

  The organometallic chelate complex used here means an organometallic chelate complex containing a single metal or an organometallic chelate complex containing a plurality of metals in a uniform composition. As an organometallic chelate complex containing a single metal, an organometallic chelate complex aqueous solution is prepared by reacting a metal or a metal compound thereof with an organic chelating agent, and crystallization is performed from the aqueous solution. It is preferable to use a complex crystal or a powder obtained by spray drying the aqueous solution. As an organometallic chelate complex containing a plurality of metals in a uniform composition, a metal simple substance of the constituent metal element or a metal compound thereof and an organic chelating agent, and / or an organometallic chelate complex of the constituent metal element in terms of metal nitride It is preferable to use a powder obtained by preparing a clear organic metal chelate complex aqueous solution by mixing so as to have a predetermined metal composition, and spray drying the aqueous solution.

  Although the present invention is configured as described above, in short, it is a method of using a powder and / or crystal containing an organometallic chelate complex as a raw material for synthesizing a metal nitride, and heat-treating it in a nitrogen-containing atmosphere. If the powder and / or crystal containing such an organometallic chelate complex is fired or heat-treated in a nitrogen-containing atmosphere, a metal nitride can be obtained. Monometallic element-based metal nitrides are obtained from organometallic chelate complexes containing a single metal, and highly compositionally controlled multimetallic element-based metal nitrides are derived from organometallic chelate complexes containing multiple metals. can get.

  Next, a method for producing the organometallic chelate complex will be described. First, a method for producing an organometallic chelate complex containing a single metal will be described.

  When producing an organometallic chelate complex containing a single metal, first, an organometallic chelate complex aqueous solution is prepared from an organic chelating agent and metal ions in a solvent. There is no special restriction | limiting in the method of producing organic metal chelate complex aqueous solution, For example, the method of making it react in an aqueous solvent using an organic chelating agent and a metal compound is mentioned.

  The organic chelating agent is preferably ethylenediaminetetraacetic acid, 1,2-cyclohexanediaminetetraacetic acid, dihydroxyethylglycine, diaminopropanoltetraacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediacetic acid, ethylenediaminedipropionic acid, hydroxyethylenediaminetriacetic acid, Glycol ether diamine tetraacetic acid, hexamethylene diamine tetraacetic acid, ethylenediamine di (o-hydroxyphenyl) acetic acid, hydroxyethyliminodiacetic acid, iminodiacetic acid, 1,3-diaminopropanetetraacetic acid, 1,2-diaminopropanetetraacetic acid, Nitrilotriacetic acid, nitrilotripropionic acid, triethylenetetraminehexaacetic acid, ethylenediamine disuccinic acid, 1,3-diaminopropane disuccinic acid, glutamic acid-N, N-diacetic acid, asphalt Water-soluble aminocarboxylic acid chelating agents such as laginic acid-N, N-diacetic acid; water-soluble organic acid chelating agents such as hydroxycarboxylic acids such as gluconic acid, citric acid, tartaric acid and malic acid. . As the aminocarboxylic acid chelating agent and the organic acid chelating agent, an ammonium salt or an amine salt thereof can also be used. Aminocarboxylic acid chelating agents and organic acid chelating agents are composed only of carbon, nitrogen, oxygen, and hydrogen, and carbon, oxygen, and hydrogen are removed by heat treatment. Nitride can be easily obtained. Among aminocarboxylic acid-based chelating agents, nitrilotriacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid can obtain an organometallic chelate complex more easily, and the obtained organometallic chelate complex is an aqueous solution. Among them, it is particularly preferably used because it exists more stably.

  Examples of the metal compound include carbonates, nitrates, hydroxides, oxides, and inorganic acid salts.

  Since the molar ratio of the organic chelating agent to the metal ion varies depending on the type of the organic chelating agent and the valence of the metal ion, it cannot be determined unconditionally. However, there is no problem as long as it is at least the molar ratio necessary for forming a stable organometallic chelate complex in an aqueous solution. The amount of the organic chelating agent used is preferably 1.0 to 1.5 times the molar equivalent of the metal ion.

  Next, an organometallic chelate complex is obtained from the aqueous organometallic chelate complex solution. The method for obtaining the organometallic chelate complex is not particularly limited, and examples thereof include a crystallization method by concentration, a precipitation method in which a hardly soluble organic solvent is added for precipitation, and an evaporation to dryness method in which an aqueous solvent is volatilized and removed. Of these, the crystallization method is particularly preferable. With this method, a higher-purity organometallic chelate complex is easily obtained.

  When carbonate, hydroxide, or oxide is used as the metal compound, a method of pulverizing by evaporation to dryness is also preferable. In this case, since excess ions or the like do not remain after powderization, the obtained organometallic chelate complex has a high purity. Although there is no particular limitation on the evaporation to dryness method, a spray drying method that can instantaneously form spherical fine particles is preferable.

  Next, a method for producing an organometallic chelate complex containing the plurality of metals in a uniform composition will be described.

  In producing an organometallic chelate complex containing a plurality of metals in a uniform composition, first, an organometallic chelate complex aqueous solution adjusted to have a predetermined metal composition in terms of the target metal nitride is prepared. The method for producing the aqueous solution is not particularly limited, but the following method is preferable.

  A metal or a metal compound thereof is precisely weighed so as to obtain a predetermined metal composition in terms of the target metal nitride, and reacted with an organic chelating agent to prepare a clear aqueous solution of an organic metal chelate complex. At this time, an organic chelating agent having an equivalent amount or more for each metal is used so that all metals completely form an organometallic chelate complex. Although there will be no restriction | limiting in particular if the usage-amount of an organic chelating agent is an excess amount with respect to all the metal ions, Preferably it is the range of 1.0-1.5 times molar equivalent.

  The organic metal chelate complex aqueous solution is prepared in an aqueous medium at a temperature of 20 ° C. to a boiling point, preferably 50 to 70 ° C.

  The concentration of the organic metal chelate complex aqueous solution is preferably 1 to 30% by mass, more preferably 10 to 20% by mass as the solid content concentration. When the concentration of the organic metal chelate complex aqueous solution is 1% by mass or more, the solvent can be efficiently evaporated in the subsequent spray drying, and the energy efficiency is improved. If the concentration of the aqueous solution of the organometallic chelate complex is 30% by mass or less, complete dissolution of the organometallic chelate complex is facilitated, and solid analysis at the tip of the spray nozzle or the like is less likely to occur in the subsequent spray drying. A metal chelate complex powder can be easily obtained.

  When the organometallic chelate complex or the organic chelating agent does not completely dissolve, ammonia or amine is added and completely dissolved.

  The organic chelating agent is preferably ethylenediaminetetraacetic acid, 1,2-cyclohexanediaminetetraacetic acid, dihydroxyethylglycine, diaminopropanoltetraacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediacetic acid, ethylenediaminedipropionic acid, hydroxyethylenediaminetriacetic acid, Glycol ether diamine tetraacetic acid, hexamethylene diamine tetraacetic acid, ethylenediamine di (o-hydroxyphenyl) acetic acid, hydroxyethyliminodiacetic acid, iminodiacetic acid, 1,3-diaminopropanetetraacetic acid, 1,2-diaminopropanetetraacetic acid, Nitrilotriacetic acid, nitrilotripropionic acid, triethylenetetraminehexaacetic acid, ethylenediamine disuccinic acid, 1,3-diaminopropane disuccinic acid, glutamic acid-N, N-diacetic acid, asphalt Ragin acid -N, it can be cited such as water-soluble aminocarboxylic acid chelating agent such as N- diacetic acid, none of these monomers or oligomers or polymers can be used. In addition, as the chelating agent, a water-soluble organic acid chelating agent such as hydroxycarboxylic acid such as gluconic acid, citric acid, tartaric acid, malic acid, or an amine salt thereof can be used. Even when an aminocarboxylic acid chelating agent is used, it is preferable to use a free acid type, an ammonium salt or an amine salt. In this case, taking into consideration the chelate formation constant with each metal, the stability of the organometallic chelate complex, and the solubility of the organometallic chelate complex in water or an aqueous alkali solution, for each metal or metal compound used It is desirable to select and use an appropriate one for the above. Aminocarboxylic acid chelating agents and organic acid chelating agents are composed only of carbon, nitrogen, oxygen, and hydrogen, and carbon, oxygen, and hydrogen are removed by heat treatment. Nitride can be easily obtained. Among aminocarboxylic acid-based chelating agents, nitrilotriacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid can obtain an organometallic chelate complex more easily, and the obtained organometallic chelate complex is an aqueous solution. Among them, it is particularly preferably used because it exists more stably.

  As the metal compound, various forms such as carbonate, nitrate, hydroxide and oxide can be used. Particularly preferred as the metal compound are carbonates, hydroxides and oxides which have high reactivity and do not leave excessive ions after the reaction.

  It is also possible to use an organometallic chelate complex produced by a method for producing an organometallic chelate complex containing a single metal as a part of or all of a metal simple substance or a metal compound thereof as a constituent metal element raw material. In this method, when the reactivity as a metal such as chromium is poor, the form of carbonate, nitrate and hydroxide is not used as in titanium, and when the oxide is a very stable metal, Ga is used. Thus, it is particularly effective when the carbonate is not formed and the reactivity with the organic chelating agent is poor in the form of hydroxide or oxide. In these cases, it is desirable to produce an organometallic chelate complex solution using chloride, sulfate, or nitrate, and then produce a highly pure organometallic chelate complex crystal by crystallization or the like, and use this as a raw material. When using an organometallic chelate complex produced by the method for producing an organometallic chelate complex containing a single metal as a raw material for all constituent metal elements, an aqueous solution prepared by dissolving them in an aqueous solvent is extremely Since the purity is high, a metal nitride with very few impurities can be manufactured.

  Metal elements that are stable as oxoacids, such as silicon, molybdenum, and tungsten, may be difficult to obtain as organometallic chelate complexes. In this case, these elements can be used together with the organometallic chelate complex in the form of a metal inorganic acid such as an oxo acid to obtain an organometallic chelate complex containing a plurality of metals in a uniform composition. As a blending method when using a metal inorganic acid in combination, depending on the target metal composition of the metal nitride, the metal inorganic acid may be blended in the raw material stage before forming the organometallic chelate complex aqueous solution, Or you may mix | blend a suitable quantity of metal inorganic acids after formation of organic metal chelate complex aqueous solution. The metal inorganic acid that may be used in combination can be obtained as a uniform amorphous powder by drying by spray drying or the like from a homogeneous mixed state in an aqueous solution with the coexisting organometallic chelate complex.

  Depending on the type of metal, even if an organometallic chelate complex is formed in an aqueous solution, the metal ion undergoes oxidation and changes to an insoluble compound in water due to contact with the air or other redox action. Or an unstable phase in an aqueous solution. In order to prevent such a phenomenon, it is preferable to add a reducing agent or an antioxidant before adding the metal compound when preparing the aqueous solution of the organometallic chelate complex. Examples of the reducing agent or antioxidant include ascorbic acid, isoascorbic acid, oxalic acid, hydrazine, and the like. For example, when titanium is contained as a metal, it is preferable to stabilize titanium (III) by adding a reducing agent or an antioxidant.

  The organometallic chelate complex aqueous solution prepared as described above is then spray-dried to obtain an organometallic chelate complex containing a plurality of metals in a uniform composition. The conditions at the time of spray drying may be appropriately adjusted depending on the concentration of the solution, the solution processing speed, the amount of spray gas, the amount of hot air, and the like. The drying temperature of spray drying has an upper limit at a temperature at which organic substances are not decomposed, and a lower limit at a temperature at which sufficient drying is possible. A preferable drying temperature is in the range of 100 to 200 ° C, more preferably 140 to 180 ° C. In consideration of such a drying temperature, the organic chelating agent used in the present invention is preferably one that does not thermally decompose at a temperature of 200 ° C. or lower.

  The organometallic chelate complex containing a plurality of metals obtained by the above production method with a uniform composition is amorphous (amorphous) and has a uniform composition at the molecular level. The organometallic chelate complex containing a plurality of metals in a uniform composition exhibits a halo figure due to scattering of incident X-rays and is amorphous in terms of crystal structure. That is, when an aqueous solution of an organometallic chelate complex having a uniform composition is instantaneously dried by spray drying or the like, it becomes a solid phase while maintaining a homogeneous phase, and the resulting powder is an organometallic chelate complex containing a plurality of metals. Each metal chelate molecule is uniformly mixed at the molecular level, and each component is an amorphous one aggregated without taking a crystal form. When viewed microscopically, a slight difference is generally observed in the regularity remaining in the amorphous structure. However, the organometallic chelate complex containing a plurality of metals in a uniform composition has a very small difference in regularity compared to the prior art described above, and can be clearly differentiated from a crystalline organometallic chelate complex.

  The appearance of the organometallic chelate complex powder containing a plurality of metals in a uniform composition is substantially spherical.

  Since the organometallic chelate complex containing a plurality of metals used in the present invention in a uniform composition is produced as described above, the types and composition ratios of the component elements can be easily designed.

  Next, a method for producing a metal nitride from an organometallic chelate complex will be described.

  The organometallic chelate complex produced as described above is then nitrided to obtain a metal nitride. The nitriding treatment is performed by heat treatment in a nitrogen-containing atmosphere.

  Examples of the nitrogen-containing atmosphere include nitrogen, dinitrogen monoxide, ammonia, and the like. Any atmosphere containing at least one of them may be used, and ammonia is particularly preferable. When ammonia is used, it is preferable because nitriding can be performed at a lower temperature than when other nitrogen gas is used. Ammonia is also preferred because it is inexpensive.

  For the heat treatment in a nitrogen-containing atmosphere, for example, in the case of producing a mixed crystal containing any one of BN, AlN, GaN, and TiN, or two or more thereof, the heating temperature is preferably 500 to 1600 ° C. Is preferably in the range of 900-1500 ° C. In the case of producing InN or a mixed crystal containing it, the heating temperature is preferably 400 to 900 ° C, more preferably 450 to 800 ° C. By setting the heating temperature within the above range, it is possible to efficiently advance the formation reaction of the metal nitride while suppressing the decomposition reaction of the metal nitride.

  The organometallic chelate complex does not necessarily have to be directly nitrided. In some cases, the nitriding treatment may be performed after the organometallic chelate complex is preheated at a temperature equal to or lower than the heat treatment temperature of the nitriding treatment in an atmosphere such as air, oxygen, nitrogen, or argon.

  Next, the III-based nitride phosphor obtained by the production method of the present invention will be described.

The group III nitride phosphor obtained by the production method of the present invention is composed of In _x Ga _y Al _z N or In _x Ga _y Al _z N: M (where x + y + z = 1, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1, M represents a metal or a semimetal). That is, a nitride of at least one metal selected from group III metals consisting of In, Ga, and Al, or a group III metal nitride doped with an activator element. _{Specifically, GaN, InN, Ga p Al} 1-p N, etc. In _{p Al 1-p} N, or the general formula GaN: M and InN: M in such magnesium activator element M, zinc, silicon Or nitride which is rare earth elements etc. is illustrated.

  In the composition formula, the relationship between x, y, and z is as described above. Particularly effective as the nitride-based phosphor is that y is 0.7 or more and (x + z) is 0.3 or less. More preferably, y is 0.8 or more and (x + z) is 0.2 or less. That is, a group III element mainly composed of Ga is preferable, and a gallium nitride-based phosphor in which y is 1 and (x + z) is 0 is particularly preferable. If the main group III element is Ga, a nitride-based phosphor can be produced relatively easily.

However, even if the main group III element is a nitride-based phosphor of In or Al, the characteristics as a phosphor are not necessarily inferior. Depending on the application and required characteristics, elements other than Ga, that is, nitride phosphors mainly composed of In or Al are also effective. These also use a powder of an organometallic chelate complex obtained by spray drying the organometallic chelate complex aqueous solution as a raw material, and heat treat this to nitriding, thereby nitriding having a uniform composition as intended It can be obtained as a physical phosphor.

  The element represented by M in the composition formula is an element useful as an activator for imparting fluorescence characteristics, and includes various elements such as alkaline earth metals, transition metals, rare earth metals, and semimetals. From the viewpoint of fluorescence characteristics, elements M are preferably 2A group elements such as Mg, 2B group elements such as Zn, 4B group elements such as Si and Ge, and rare earth elements such as Ce, Pr, Eu, Tb, and Tm. It is. Among these, particularly preferred are rare earth elements such as Mg, Zn, Si, Ge, and Ce, Pr, Eu, Tb, and Tm.

  In the case of a composite nitride containing three types of Ga and Al, In and Al, Ga and In, or Ga, In, and Al as group III metals, it should be used together with M as well as when used in combination with the element indicated by M. At least it may exhibit fluorescence characteristics.

  The group III nitride phosphor obtained by the production method of the present invention can control conductivity, and is a cathode ray tube (CRT), plasma display (PDP), field emission display (FED), fluorescent display tube, fluorescent tube It is extremely useful as a phosphor material used in lamps and the like.

  As described above, according to the present invention, a metal nitride can be easily obtained by using an organometallic chelate complex as a starting material for synthesizing a metal nitride and nitriding it in a nitrogen-containing atmosphere. it can. Further, the obtained metal nitride has a very high composition control. The group III nitride phosphor obtained by the production method of the present invention can be effectively used as a phosphor material.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples as a matter of course, and may be implemented with appropriate modifications within a range that can meet the purpose described above and below. All of which are within the scope of the present invention.

Reference example 1
100 g of ethylenediaminetetraacetate gallium ammonium crystals were put into a 500 ml beaker, and water was added thereto to make a total amount of 500 g, followed by stirring to dissolve. When this solution was pulverized by a spray drying method at a drying temperature of 160 ° C., 95 g of Ga-EDTA complex powder was obtained. When 2.0 g of this complex powder was placed in a tubular furnace and heat-treated at 800 ° C., 900 ° C., 1000 ° C., or 1100 ° C. for 1 hour in an ammonia atmosphere, 0.4 g of a pale yellowish green powder was obtained.

  When this powder was identified for the crystal phase by an X-ray diffractometer, the X-ray diffraction chart of FIG. 1 was obtained. Note that the MPD type manufactured by Philips was used as the X-ray diffractometer (hereinafter, the X-ray diffractometer is the same device). It was revealed that single-phase GaN was obtained by heat treatment at 800 ° C. or higher.

Reference example 2
Ethylenediaminetetraacetic acid titanium ammonium salt 2.0g was put into the tubular furnace, and it heat-processed at 1100 degreeC for 1 hour in ammonia atmosphere, and obtained 0.6g of dark brown powder.

  When the obtained powder was crystallized with an X-ray diffractometer, it was confirmed to be single phase TiN as shown in the X-ray diffraction chart of FIG.

Example 3
1.0 g of ethylenediaminetetraacetic acid indium ammonium salt was put in a tubular furnace and heat-treated at 500 ° C. for 3 hours in an ammonia atmosphere to obtain 0.3 g of black powder. When the crystal phase of the obtained powder was identified with an X-ray diffractometer, it was confirmed to be single phase InN as shown in the X-ray diffraction chart of FIG.

Reference example 4
In a 100 ml beaker, 8.47 g of ethylenediaminetetraacetic acid was added and water was added to make a total amount of 50 g. Then, 3.87 g of 25% aqueous ammonia was added and dissolved at 25 ° C. While stirring this solution, 2.31 g of zinc oxide was added little by little to this solution, and then the temperature was raised to 100 ° C. and stirred for 30 minutes. By adding water to this solution to make a total amount of 1000 g, a colorless and transparent zinc / ethylenediaminetetraacetic acid (Zn-EDTA) complex aqueous solution was obtained. 18.72 g of the obtained Zn-EDTA complex aqueous solution (Zn content: 0.186% by mass) and 20.58 g of ethylenediaminetetraacetic acid gallium ammonium (EDTA · Ga · NH ₄ ) (Ga content: 18.0% by mass) Each was precisely weighed and placed in a 100 ml beaker, and then water was added to make a total amount of 100 g. Next, the solution was completely dissolved by stirring for 30 minutes to obtain a colorless and transparent (Ga, Zn) EDTA complex aqueous solution having a metal component composition of Ga / Zn = 1 / 0.01. When this solution was pulverized by a spray drying method at a drying temperature of 160 ° C., a (Ga, Zn) -EDTA complex powder was obtained. When 1.0 g of this complex powder was put in a tubular furnace and heat-treated at 1100 ° C. for 1 hour in an ammonia atmosphere, 0.2 g of a pale yellow powder was obtained.

  When this powder was identified for the crystal phase by an X-ray diffractometer, the X-ray diffraction chart of FIG. 4 was obtained. This X-ray diffraction chart coincides with the peak of GaN even if it contains Zn, and no impurity peak is seen, so this powder is GaN in which Zn is uniformly dissolved (Zn-doped GaN). It was confirmed.

  This powder was measured with a cathodoluminescence measuring device (excitation voltage: 3 kV). The cathodoluminescence measuring device is manufactured by Ehime Bussan Co., Ltd. (hereinafter, the cathodoluminescence measuring device is the same device). The obtained emission spectrum is as shown in FIG. 5, and the peak wavelength of emission is 430 nm.

  From these results, it was confirmed that the obtained Zn-doped GaN was a blue-violet phosphor GaN: Zn having a uniform metal-containing composition.

Reference Example 5
35.54 g of ethylenediaminetetraacetic acid was added to a 100 ml beaker, water was added to make the total amount 200 g, and then 16.23 g of 25% aqueous ammonia was added and dissolved. While stirring this solution, 4.81 g of magnesium oxide was added little by little to this solution, and then the temperature was raised to 100 ° C. and the mixture was further stirred for 30 minutes. By adding water to this solution to a total amount of 1000 g, a colorless and transparent magnesium-ethylenediaminetetraacetic acid (Mg-EDTA) complex aqueous solution was obtained. 4.46 g of the obtained Mg-EDTA complex aqueous solution (Mg content: 0.29% by mass) and 20.58 g of ethylenediaminetetraacetic acid gallium ammonium (EDTA · Ga · NH ₄ ) (Ga content: 18.0% by mass) Each was precisely weighed and placed in a 100 ml beaker, and then water was added to make a total amount of 100 g. Subsequently, it stirred for 30 minutes at 25 degreeC, and melt | dissolved completely, and the colorless and transparent (Ga, Mg) -EDTA complex aqueous solution whose metal component composition is Ga / Mg = 1 / 0.01 was obtained. When this solution was pulverized by a spray drying method at a drying temperature of 160 ° C., a (Ga, Mg) -EDTA complex powder was obtained. When 1.0 g of this complex powder was put in a tubular furnace and heat-treated at 1100 ° C. for 1 hour in an ammonia atmosphere, 0.2 g of a pale yellow powder was obtained.

  When this powder was identified for the crystal phase by an X-ray diffractometer, the X-ray diffraction chart of FIG. 4 was obtained. This X-ray diffraction chart coincides with the peak of GaN even if it contains Mg, and no impurity peak is seen. Therefore, this powder is GaN in which Mg is uniformly dissolved (Mg-doped GaN). It was confirmed.

  This powder was measured with a cathodoluminescence measuring device (excitation voltage: 3 kV). The obtained emission spectrum is as shown in FIG. 5, and the peak wavelength of emission was 430 nm.

  From these results, it was confirmed that the obtained Mg-doped GaN was the blue-violet phosphor GaN: Mg.

Reference Example 6
In a 100 ml beaker, 19.21 g of ethylenediaminetetraacetic acid was added, water was added to make the total amount 200 g, and 8.94 g of 25% aqueous ammonia was added and dissolved. While stirring this solution, 12.05 g of terbium oxide was added little by little to this solution, and then the temperature was raised to 100 ° C. and stirred for 30 minutes. By adding water to this solution to a total amount of 1000 g, a colorless and transparent terbium-ethylenediaminetetraacetic acid (Tb-EDTA) complex aqueous solution was obtained. 4.46 g of the obtained aqueous solution of Tb-EDTA complex (Tb content: 0.29% by mass) and 20.58 g of ethylenediaminetetraacetic acid gallium ammonium (EDTA · Ga · NH ₄ ) (Ga content: 18.0% by mass) Each was precisely weighed and placed in a 100 ml beaker, and then water was added to make a total amount of 100 g. Next, the solution was completely dissolved by stirring for 30 minutes to obtain a colorless and transparent (Ga, Tb) -EDTA complex aqueous solution having a metal-containing composition of Ga / Tb = 1 / 0.01. When this solution was pulverized by a spray drying method at a drying temperature of 160 ° C., a (Ga, Tb) -EDTA complex powder was obtained. When 1.0 g of this complex powder was placed in a tubular furnace and heat-treated at 1100 ° C. for 5 hours in an ammonia atmosphere, 0.2 g of a pale yellow powder was obtained.

  When this powder was identified for the crystal phase by an X-ray diffractometer, the X-ray diffraction chart of FIG. 6 was obtained. This X-ray diffraction chart coincides with the peak of GaN even if it contains Tb, and no impurity peak is observed. Therefore, this powder is GaN in which Tb is uniformly dissolved (Tb-doped GaN). Was confirmed.

  This powder was measured with a cathodoluminescence measuring device (excitation voltage: 3 kV). The obtained emission spectrum was as shown in FIG. 5, and the peak wavelength of emission was 545 nm.

  From these results, it was confirmed that the obtained Tb-doped GaN was a green phosphor GaN: Tb.

  Further, it was confirmed that a nitride obtained by substituting a part of Ga with In or Al also has light emission characteristics.

Example 7
In a 100 ml beaker, 25.1 g of citric acid was added, water was added to make the total amount 100 g, and then dissolved by stirring. While stirring this solution, 15.7 g of indium nitrate n-hydrate was added little by little to this solution, and the mixture was stirred at room temperature for 30 minutes. When water was added to this solution to make a total amount of 200 g, a colorless and transparent indium-citric acid (In-Cit) complex aqueous solution was obtained. 25.42 g of the obtained In-Cit complex aqueous solution (In content: 2.40% by mass) and 20.58 g of ethylenediaminetetraacetic acid gallium ammonium (EDTA · Ga · NH ₄ ) (Ga content: 18.0% by mass) Each was precisely weighed and placed in a 100 ml beaker, and then water was added to make a total amount of 100 g. Next, the mixture was stirred for 30 minutes and completely dissolved to obtain a colorless and transparent (Ga-EDTA, In-Cit) mixed complex aqueous solution having a metal component composition of Ga / In = 0.9 / 0.1. This solution was pulverized by a spray drying method at a drying temperature of 160 ° C. to obtain a (Ga-EDTA, In-Cit) mixed complex powder. When 1.0 g of this complex powder was placed in a tube furnace and heat-treated at 500 ° C. for 1 hour in an ammonia atmosphere, 0.2 g of a pale yellow powder was obtained.

  When this powder was identified by the X-ray diffractometer, the X-ray diffraction chart was consistent with the peak of GaN even when it contained In, and no impurity peak was observed due to In. From this, it was confirmed that this powder was GaN (In-doped GaN) in which In was uniformly dissolved.

  When this powder was measured with a cathodoluminescence measuring device (excitation voltage: 3 kV), blue light emission was confirmed.

  According to the present invention, a metal nitride can be easily obtained by using an organometallic chelate complex as a starting material for synthesizing a metal nitride and heat-treating it in a nitrogen-containing atmosphere. Further, the obtained metal nitride is highly controlled in composition. The group III nitride phosphor obtained by the production method of the present invention is used as a phosphor material used in a cathode ray tube (CRT), a plasma display (PDP), a field emission display (FED), a fluorescent display tube, a fluorescent lamp, and the like. It can be used very effectively.

Claims (5)

A process for producing a metal nitride of InN, comprising heat-treating an organometallic chelate complex containing a single metal at a temperature of 400 to 900 ° C. in a nitrogen-containing atmosphere,
As the organometallic chelate complex containing a single metal, an organometallic chelate complex crystal crystallized from an organometallic chelate complex aqueous solution obtained by reacting the metal or a metal compound thereof with an aminocarboxylic acid chelating agent, or A method for producing a metal nitride, comprising using an organometallic chelate complex powder obtained by spray drying the organometallic chelate complex aqueous solution. A process for producing a mixed crystal metal nitride containing In and Ga, in which an organometallic chelate complex having a uniform composition containing a plurality of metals is heated at a temperature of 400 to 900 ° C. in a nitrogen-containing atmosphere,
As the organometallic chelate complex having a uniform composition containing a plurality of metals, a single metal of the constituent metal element or a metal compound thereof and an aminocarboxylic acid chelating agent, and / or an aminocarboxylic acid metal chelate complex of the constituent metal element A method for producing a metal nitride, comprising using an organometallic chelate complex powder obtained by spray drying an aqueous solution of an organometallic chelate complex prepared by mixing so as to have a predetermined metal composition. The method for producing a metal nitride according to claim 2 , wherein the mixed crystal metal nitride containing In and Ga is a phosphor. As the aminocarboxylic acid chelating agent, any of claims 1 to 3 using at least one selected from nitrilotriacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid and the group consisting of an amine salt thereof preparation of metal nitride as claimed in either. The method for producing a metal nitride according to any one of claims 1 to 4 , wherein an atmosphere containing at least one of nitrogen, dinitrogen monoxide, and ammonia is adopted as the nitrogen-containing atmosphere.

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