JP2000319653A - GaN PHOSPHOR - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide GaN based phosphors which emit light with sufficient brightness for practical purposes by the excitation with an electron beam. SOLUTION: Both an acceptor and a donor are added to a GaN phosphor matrix to dissolve the presence of excess holes with electric field compensation to control formation of the nitrogen defect and as a result, deterioration of the crystallinity of the matrix is controlled. The condition for the acceptor or the donor to come to impurities to GaN is that the acceptor or the donor has a coordination number of 6 and approximates to the ionic radius of Ga or N of the matrix element. The acceptor is a group II element (Mg3+ or Zn2+), and the donor is a group IV or VI element (Si4+, Ge4+, Sn4+, S2- or O2-). 20 g Ga2S3, 0.4 g MgS, and 0.003 g SiO2 are mixed, placed on a firing boat and fired at 1,150 deg.C for 2 hr to obtain a GaN:Mg and Si phosphor. This phosphor emits blue light when excited with a 2 kV electron beam. When the Si concentration is fixed, not lower than 50% of the maximum value of the relative luminance can be obtained at a Mg concentration of 0.002-0.2 mol%. The luminance is higher when the Si (donor) concentration is higher than the Mg (acceptor) concentration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a compound of the general formula Ga _1-x I
n _x N: about GaN phosphor represented by A (0 ≦ x <1) .

[0002]

2. Description of the Related Art In recent years, GaN is LE
It is known as a material that emits blue and green light with high luminance in light emitting elements such as D and LD.

[0003] Although attempts have been made in the past to cause this phosphor to emit light with an electron beam, powdered ones have not yet achieved practical brightness and have not been put to practical use.

[0004]

The main reason why luminance cannot be obtained is that, unlike other phosphor materials, it is difficult to perform nitriding. That is, the temperature at which the material is nitrided (7
Since the difference between the temperature (00 ° C. to 1000 ° C.) and the temperature at which decomposition starts (950 ° C. or more) is small, nitridation and decomposition tend to proceed simultaneously in a normal reaction by heating. For this reason, although GaN can be produced, it has not been possible to produce GaN having high crystallinity enough to be used as a phosphor by reducing nitrogen defects.

Further, the GaN phosphor needs to be doped with an impurity serving as a light emission center, but in a conventional attempt, only an impurity serving as an acceptor has been doped. When an impurity serving as an acceptor is doped, the number of nitrogen defects in GaN further increases and crystallinity deteriorates.

It is an object of the present invention to provide a GaN-based phosphor that emits light with a practically sufficient luminance by exciting an electron beam.

[0007]

The phosphor described in claim 1 is represented by Ga _1-x In _x N: A, B (0 ≦ x <1), and A is selected from Zn and Mg. B is a phosphor that is at least one element selected from Sn, S, O, Si, and Ge, wherein A is in a range of 0.002 to 0.2 mol%. Wherein said B is in the range of 0.003 to 0.3 mol%;
The ratio of A to B is B / A> 1.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In order to solve the above-mentioned problem, the present inventors have added not only an acceptor but also a donor as an impurity to be doped into a phosphor matrix, and eliminated the presence of excess holes by charge compensation. Thus, it was considered effective to suppress the generation of nitrogen defects in GaN and thereby suppress the deterioration of the crystallinity of the phosphor host crystal. For this purpose, the present inventors conducted various experiments under different conditions, and studied the types and amounts of the acceptor and the donor to be doped and the ratio between the two, as shown in the following examples.

As a result, the donor impurity concentration of the GaN phosphor is made higher than the acceptor impurity concentration. As a result, the generation of nitrogen defects in the GaN phosphor base material due to the impurity doping was suppressed, the decrease in crystallinity was suppressed, and a GaN phosphor capable of obtaining a practical brightness by electron impact was realized.

[0010] Conditions for becoming an acceptor or donor impurity with respect to GaN must be hexacoordination and close to the ionic radius of Ga or N, which is a parent element to be substituted. The acceptor is a Group 2 element, and the donor is a Group 4 or Group 6 element. Specifically, the ions shown in Table 1 below become the acceptor or donor impurities of GaN.

[0011]

[Table 1]

[0012]

EXAMPLES (1) Example 1 A method of manufacturing a GaN: Mg, Si phosphor will be described. Ga ₂ S ₃ is used as a Ga source material (base element compound). MgS is used as a raw material of Mg, which is a doping substance serving as an acceptor. SiO ₂ is used as a raw material of Si, which is a doping material serving as a donor.
Specifically, 20 g of Ga ₂ S ₃ and 0.4 g of MgS
And 0.003 g of SiO ₂ are mixed well and placed on a firing boat. MgS is liable to be scattered by baking in ammonia, so it is necessary to prepare MgS in excess. This firing boat is placed on a uniform path in a tubular road, and fired at 1150 ° C. for 2 hours while flowing ammonia at 350 ml / min to obtain G
aN: Mg, Si phosphor was obtained. This GaN: Mg, S
When the i phosphor was excited by an electron beam of 2 kV, blue light was emitted.

As a result of the analysis, 0.02 mol% of Mg and 0.05 mol of Si were contained in the GaN: Mg, Si phosphor.
%was detected. As a result of examining the luminance dependence of the Mg concentration and the Si concentration in the GaN: Mg, Si phosphor as described above, the results shown in FIGS. 1 and 2 were obtained.

As shown in FIG. 1, in a GaN: Mg, Si phosphor, when the Si concentration is fixed at 0.2 mol%, the maximum value is 100 when the Mg concentration is 0.002 to 0.2 mol%. The relative luminance is about 50% or more, which is good. When the Mg concentration is 0.005 to 0.07 mol%, the relative luminance is more preferably about 80% or more, which is more preferable.

As shown in FIG. 2, when the Mg concentration is fixed at 0.003 mol% in the GaN: Mg, Si phosphor, the maximum value is 100 when the Si concentration is 0.003-0.3 mol%. The relative luminance is about 50% or more, which is good. When the Si concentration is 0.01 to 0.1 mol%, the relative luminance is more preferably about 80% or more, and it is more preferable.

FIGS. 1 and 2 show that the luminance is higher when the Si (donor) concentration is higher than the Mg (acceptor) concentration.

(2) Example 2 A method for producing a GaN: Zn, Ge phosphor will be described. Ga ₂ S ₃ is used as a Ga source material (base element compound). ZnS is used as a source material of Zn which is a doping material serving as an acceptor. GeO ₂ is used as a source material of Ge, which is a doping material serving as a donor.
Specifically, 20 g of Ga ₂ S ₃ and 0.4 g of ZnS
And 0.005 g of GeO ₂ were mixed well with each other, placed on a firing boat, and fired in the same manner as in Example 1 to obtain GaN: Z.
An n, Ge phosphor was obtained. This GaN: Zn, Ge phosphor emits blue light by electron beam excitation.

As a result of analysis, this GaN: Zn, Ge phosphor has 0.02 mol% of Zn and 0.05 mol of Ge.
%was detected. As a result of examining the luminance dependency of the Zn concentration and the Ge concentration in the GaN: Zn, Ge phosphor as described above, the results shown in FIGS. 3 and 4 were obtained.

As shown in FIG. 3, in a GaN: Zn, Ge phosphor, when the Ge concentration is fixed at 0.2 mol%, the maximum value is 100 when the Zn concentration is 0.002 to 0.2 mol%. The relative luminance is about 50% or more, which is good. When the Ge concentration is 0.005 to 0.1 mol%, the relative luminance is more preferably about 80% or more.

As shown in FIG. 4, in a GaN: Zn, Ge phosphor, when the Zn concentration is fixed at 0.003 mol%, the maximum value is 100 when the Ge concentration is 0.003-0.3 mol%. The relative luminance is about 50% or more, which is good. When the Ge concentration is 0.01 to 0.1 mol%, the relative luminance is more preferably about 80% or more, and it is more preferable.

FIGS. 3 and 4 show that the luminance is higher when the Ge (donor) concentration is higher than the Zn (acceptor) concentration.

(3) Example 3 A method for manufacturing a GaInN: Mg, Si phosphor will be described. Ga
As an In source materials (matrix element compounds), Ga ₂
S ₃ and In ₂ S ₃ are used. MgS is used as a raw material of Mg, which is a doping substance serving as an acceptor. SiO ₂ is used as a raw material of Si, which is a doping material serving as a donor. Specifically, Ga ₂ S ₃ is 2
0 g, 10 g of In ₂ S ₃ , 0.4 g of MgS,
0.003 g of SiO ₂ was mixed well with each other, placed on a firing boat, and fired in the same manner as in Example 1 to obtain GaInN: M.
g, Si phosphor was obtained.

As a result of the analysis, the luminance dependency of the Mg concentration and the Si concentration was examined. As a result, the first embodiment shown in FIGS.
Approximately the same result was obtained.

(4) Example 4 A method for producing a GaN: Zn, S phosphor will be described. Ga ₂ S ₃ is used as a Ga source material (base element compound). As a source material of Zn as a doping material serving as an acceptor and S as a doping material serving as a donor, ZnS is used.
Use Specifically, 20 g of Ga ₂ S ₃ and Zn
0.2 g of S, mixed well with each other, placed on a firing boat,
By firing in the same manner as in Example 1, a GaN: Zn, S phosphor was obtained.

In this GaN: Zn, S phosphor,
As a result of examining the luminance dependence of the Zn concentration and the S concentration as a result of appropriately adding S and Zn alone and changing the concentration, the results shown in FIGS. 5 and 6 were obtained.

As shown in FIG. 5, when the S concentration is fixed at 0.2 mol% in the GaN: Zn, S phosphor,
When the Zn concentration is 0.002 to 0.2 mol%, the relative luminance with the maximum value being 100 is about 50% or more, which is good. When the Zn concentration is 0.006 to 0.07 mol%, the relative luminance is more preferably about 80% or more.

As shown in FIG. 6, when the Zn concentration is fixed at 0.003 mol% in the GaN: Zn, S phosphor, the maximum value is 100 when the S concentration is 0.003-0.3 mol%. The relative luminance is about 50% or more, which is good. When the S concentration is 0.008 to 0.1 mol%, the relative luminance is more preferably about 80% or more, which is more preferable.

FIGS. 5 and 6 show that the luminance is higher when the S (donor) concentration is higher than the Zn (acceptor) concentration. The tendency was the same as in Examples 1 to 3.

[0029]

According to the present invention, Ga _1-x In _x N (0
≦ x <1) In a GaN phosphor represented by ≦ x <1), at least one element selected from Zn and Mg is used as an acceptor, and at least one element selected from Sn, S, O, Si and Ge is used as a donor. Used, more preferably 0.002 to 0.2 mol% of the added amount of the acceptor.
And the amount of the donor added is 0.003 to 0.3 m.
ol%, and even more preferably, the ratio of acceptor A to donor B is B / A> 1. Therefore, according to the present invention, the following effects can be obtained.

1. The charge compensation of the acceptor and the donor suppresses the generation of nitrogen defects in GaN,
It does not disturb the host crystal.

2. The effect (1) allows doping of acceptor and donor impurities without lowering the crystallinity, so that a GaN phosphor having high emission intensity can be obtained.

[Brief description of the drawings]

FIG. 1 shows a phosphor according to a first embodiment in which doped Mg
FIG. 7 is a diagram illustrating a dependence characteristic of luminance on density.

FIG. 2 shows a phosphor of the first embodiment,
FIG. 7 is a diagram illustrating a dependence characteristic of luminance on density.

FIG. 3 shows a phosphor of the second embodiment doped with Zn;
FIG. 7 is a diagram illustrating a dependence characteristic of luminance on density.

FIG. 4 shows a phosphor of the second embodiment in which doped Ge is used.
FIG. 7 is a diagram illustrating a dependence characteristic of luminance on density.

FIG. 5 shows a phosphor of a fourth embodiment in which doped Zn is used.
FIG. 7 is a diagram illustrating a dependence characteristic of luminance on density.

FIG. 6 is a diagram showing the dependence of the luminance on the doped S concentration in the phosphor of the second embodiment.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Fumiaki Kataoka 629 Oshiba, Mobara-shi, Chiba Futaba Electronics Co., Ltd. (72) Inventor Hitoshi Toki 629 Oshiba, Mobara-shi, Chiba Futaba Electronics Co., Ltd. Reference) 4H001 CA04 XA07 XA31 XA49 YA05 YA08 YA12 YA14 YA16 YA30 YA32 YA50

Claims (1)

[Claims] 1. Ga _1-x In _x N: A, B (0 ≦ x <
A is at least one element selected from Zn and Mg, and B is Sn, S, O, Si, Ge
The phosphor which is at least one element selected from the group consisting of: A is in the range of 0.002 to 0.2 mol%, B is in the range of 0.003 to 0.3 mol%, And a ratio of B to B / A> 1.