JP2008069035A - Method for producing nitride and oxynitride - Google Patents

Abstract

Disclosed is a method for producing a nitride and an oxynitride that are excellent in reactivity and do not cause uneven coloring or a difference in the degree of nitriding of a product.
A compound represented by a composition formula KMO ₂ (M is a metal element) containing at least one metal element selected from Ga, Ge, Zn, In, and Sn is heated under a flow of ammonia. K ₂ ZnGeO ₄ was heated at 700 to 1000 ° C. under ammonia flow, or KGaO ₂ was heated at 700 to 1000 ° C. under ammonia flow.
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Description

  The present invention relates to a method for producing nitrides and oxynitrides.

  Nitride and oxynitride typified by GaN used for blue LEDs are widely applied to LEDs and photocatalysts, and have a wide range of applications. It is also expected to be used as an optical material such as a phosphor.

As a conventional method for producing nitrides and oxynitrides, a method using metal powder or amide as a starting material is known (see, for example, Patent Document 1).
JP 2002-241112 A

  However, the conventional synthesis method using oxide or metal powder as a starting material has a problem that color reactivity and a difference in the degree of nitridation of the product occur due to poor reactivity. In order to increase the reactivity, there is a method using a special precursor such as an amide, but such a precursor is expensive and it is difficult to control the reactivity. Therefore, it is difficult to control the composition of the product in a complex composition or a nitride or oxynitride containing a plurality of component elements.

  In view of the above problems, an object of the present invention is to provide a nitride and oxynitride manufacturing method capable of manufacturing nitrides and oxynitrides that are uniform and excellent in optical properties.

As a result of various studies to achieve the above-mentioned problems, the inventors have found that GaN is produced in a single phase by heating KGaO ₂ under ammonia flow, and the present invention has been completed.

That is, the nitride and oxynitride production method of the present invention is represented by the general formula KMO ₂ (M is a metal element) containing at least one metal element selected from Ga, Ge, Zn, In, and Sn. The compound is heated under a flow of ammonia.

_Also characterized in that the K 2 ZnGeO ₄ is heated at 700 to 1000 ° C. under ammonia flow.

Furthermore, KGaO ₂ is heated at 700 to 1000 ° C. under ammonia flow.

  According to the method for producing nitrides and oxynitrides of the present invention, nitrides and oxynitrides that are uniform and excellent in optical properties can be easily produced.

The method for producing a nitride and an oxynitride according to the present invention includes a compound represented by a composition formula KMO ₂ (M is a metal element) containing at least one metal element selected from Ga, Ge, Zn, In, and Sn. Heating under ammonia flow.

KMO ₂ generally has a structure in which K exists around the MO ₄ tetrahedron, the bond between K and tetrahedron is weak, and has a metastable structure that decomposes when heated at 700 to 1000 ° C. When this KMO ₂ is baked under the flow of ammonia, K is volatilized from the crystal structure and N derived from ammonia is added to produce oxynitride or nitride. The present invention makes it possible to perform uniform nitridation by introducing N when the compound is decomposed by heating under ammonia flow by utilizing the property of the compound represented by KMO ₂ that is easily decomposed. Is.

Here, the precursor KMO ₂ is obtained by wet-mixing K ₂ CO ₃ and MO _x with acetone or the like and baking. KMO ₂ is obtained by mixing at a molar ratio of K ₂ CO ₃ : MO _x = 1: 2. The firing temperature is preferably 700 ° C. or higher.

For example, when K ₂ CO ₃ , ZnO, and GeO ₂ are mixed and baked, K ₂ ZnGeO ₄ is synthesized in a single phase. Thus, an oxynitride of Zn and Ge to which N is added is obtained. When heating is continued, nitride GeZnN ₂ is generated, and when heating is performed, Zn is volatilized and nitride Ge ₃ N ₄ is obtained.

Alternatively, when K ₂ CO ₃ and Ga ₂ O ₃ are mixed and calcined, KGaO ₂ is synthesized in a single phase, and when this is heated at 700 to 1000 ° C. under a flow of ammonia, K volatilizes and is nitrided. The product GaN is obtained.

  Thus, various nitrides or oxynitrides can be produced by appropriately selecting the type of the metal element M. According to the method of the present invention, uniform nitrides and oxynitrides having excellent optical properties can be easily produced.

  The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. Hereinafter, it demonstrates in detail based on a specific example.

First, K ₂ ZnGeO ₄ as a precursor was synthesized. Using K ₂ CO ₃ , ZnO, and GeO ₂ as raw materials, these raw materials were weighed at a molar ratio of K ₂ CO ₃ : ZnO: GeO ₂ = 1: 1: 1, wet-mixed with acetone, and mixed at 24 ° C. at 24 ° C. Time firing was performed. The XRD pattern of the obtained sample is as shown in the lower part of FIG. 1, and it was confirmed that K ₂ ZnGeO ₄ was synthesized in a single phase.

  Next, 0.5 to 1.0 g of the precursor obtained above was heated at 800 ° C. under an ammonia flow of 50 ml / min. In 3 hours after the start of heating under ammonia flow, the composition did not change as shown in the second row from the bottom of FIG.

Further, a change in composition was observed 6 hours after the start of heating, and as shown in the second row from the top of FIG _. It was confirmed that a mixture of ₇ GeN _1.8 O and Zn _1.231 Ge _0.689 O _0.782 N _1.218 was produced.

Further, after heating for 3 hours after the start of heating, heating was further performed for 6 hours. As a result, the formation of GeZnN ₂ was confirmed as shown in the upper part of FIG.

Further, at 12 hours after the start of heating, as shown in the second row from the bottom of FIG. 2, it was confirmed that Zn content was further volatilized and α-Ge ₃ N ₄ was generated almost in a single phase.

K ₂ ZnGeO ₄ has a metastable structure in which K and Zn exist around the GeO ₄ tetrahedron, the bond between K and Zn and the tetrahedron is weak, and it decomposes at high temperatures. In this example, it was confirmed that oxynitride and nitride can be generated by firing K ₂ ZnGeO ₄ under ammonia flow.

First, KGaO ₂ as a precursor was synthesized. Using K ₂ CO ₃ and Ga ₂ O ₃ as raw materials, these raw materials were weighed at a molar ratio of K ₂ CO ₃ : Ga ₂ O ₃ = 1: 2, wet-mixed with acetone, and heated at 800 ° C. for 24 hours. Firing was performed. The XRD pattern of the obtained sample is as shown in the lower part of FIG. 3, and it was confirmed that KGaO ₂ was synthesized in a single phase.

  Next, 1-2 g of the precursor obtained above was heated at 800 ° C. for 12 hours or 24 hours, or at 900 ° C. for 12 hours or 24 hours under an ammonia flow of 50 ml / min. Under any firing condition, it was confirmed that GaN was formed in a single phase as shown in FIG.

  FIG. 4 shows ultraviolet-visible diffuse reflection spectra of GaN obtained under the respective firing conditions. No level of impurities or the like was observed at the absorption edge, and it was confirmed that GaN having uniform and excellent optical characteristics was obtained.

KGaO ₂ has a metastable structure in which K is present around the GaO ₄ tetrahedron, the bond between K and tetrahedron is weak, and it decomposes at high temperatures. In this example, it was confirmed that nitrides can be generated by firing KGaO ₂ under ammonia flow.

It is an XRD pattern of the resulting composition by precursor _K 2 ZnGeO ₄ and calcination obtained in Example 1. _{2 is} an XRD pattern of α-Ge ₃ N ₄ obtained in Example 1. FIG. It is a GaN of the XRD pattern obtained by precursor KGaO ₂ and calcined obtained in Example 2. 3 is an ultraviolet-visible diffuse reflection spectrum of GaN obtained in Example 2.

Claims (3)

A nitride characterized by heating a compound represented by a composition formula KMO ₂ (M is a metal element) containing at least one metal element selected from Ga, Ge, Zn, In, and Sn under a flow of ammonia; Production method of oxynitride. A method for producing a nitride and an oxynitride, wherein K ₂ ZnGeO ₄ is heated at 700 to 1000 ° C. under a flow of ammonia. A method for producing a nitride and an oxynitride, wherein KGaO ₂ is heated at 700 to 1000 ° C. under ammonia flow.

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