JP2001308382A - Light-emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting element wherein structure and manufactur ing are simpler than a conventional element while light-emission characteristics and brightness are improved. SOLUTION: A phosphor is added on an AlxByGa1-x-yN semiconductor layer which is injected with electron and positive holes, so that the phosphor emits light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device having a high luminance and a very narrow emission spectrum wavelength width in a range from ultraviolet light to visible light.

[0002]

2. Description of the Related Art As a conventional light emitting device, Ga on a substrate is used.
There is an element in which an N layer is provided and a glass plate on which a phosphor and an ITO film are applied via an insulating spacer is provided thereon.
FIG. 6C is a schematic sectional view of an example of such a light emitting device. As shown in this figure, the conventional light emitting device
A GaN layer 42 is formed on a substrate 41, an insulating spacer 44 is provided thereon, and the phosphor 4
5 and a glass plate 47 on which an ITO film 46 is applied. This light emitting element is manufactured, for example, through the steps shown in FIGS. 6 (a) to 6 (c). In the step (a), GaN is placed on a substrate 41 such as conductive SiC.
Layer 42 is grown epitaxially. Next, in a step (b), an electrode 43 is formed on the surface of the substrate 41 opposite to the GaN layer 42. In step (c), an insulating spacer 44 is provided on the GaN layer 42, and a phosphor 45 and a glass plate 47 coated with an ITO film 46 are provided on the insulating spacer 44. In the light emitting device thus obtained, by applying a negative voltage to the electrode 43 and applying a positive voltage to the ITO film 46, as shown in FIG. Is emitted and collides with the phosphor 45 to emit light.
Light is extracted outside through the glass plate 47.

[0003]

As described above, in the conventional light emitting device, the insulating spacer is provided between the GaN layer and the glass plate provided with the phosphor layer and the ITO film. , That is, the distance between the GaN layer and the phosphor layer is 10 to 100 microns. It is extremely difficult to install and fix such an insulating spacer having a fine structure between a GaN layer and a glass plate provided with a phosphor layer or an ITO layer.

[0004] Further, the light emitting element as described above has a large variation in luminance and the like, and has a problem in reproducibility of characteristics.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a light-emitting element which is simpler in structure and manufacture than conventional elements, and has improved light-emitting characteristics and luminance. .

[0006]

SUMMARY OF THE INVENTION The present invention provides an Al _{x By y} Ga
_1-xy N semiconductor layer (however, 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x
+ Phosphor was added to y ≦ 1), wherein the Al _x B _y Ga _1-xy
A light emitting element characterized in that electrons and holes are injected into an N semiconductor layer to cause the phosphor to emit light.

Further, according to a preferred aspect of the present invention, there is provided a light emitting device having a light emitting portion formed between a first electrode and a second electrode, wherein the light emitting portion is formed on a conductive substrate.
_{l x B y Ga 1-xy} N semiconductor layer (where, 0 ≦ x ≦ 1,0 ≦
y ≦ 1, x + y ≦ 1), wherein the Al _x
The phosphor is added to B _y Ga _1-xy N semiconductor layer, the _{Al x B y Ga 1-xy} N light emitter of the semiconductor layer by applying a voltage to the first electrode and the second electrode A light-emitting element characterized by emitting light is provided.

According to another aspect of the present invention, there is provided a light emitting device including a light emitting portion formed between a first electrode and a second electrode, wherein the light emitting portion is formed on a conductive substrate. And p
Type _{Al x2 B y2 Ga 1-x2} -y2 N semiconductor layer (where, 0 ≦ x2
≦ 1, 0 ≦ y2 ≦ 1, x2 + y2 ≦ 1) and n-type Al
_{x2 B y2 Ga 1-x2-} y2 N semiconductor layer (where, 0 ≦ x2 ≦ 1,
Al _x1 sandwiched by 0 ≦ y2 ≦ 1, x2 + y2 ≦ 1)
B _y1 Ga _1-x1-y1 N semiconductor layer (provided that 0 ≦ x1 ≦ 1, 0
≦ y1 ≦ 1, x1 + y1 ≦ 1), a phosphor is added to the Al _{x1 By 1} Ga _{1 -x 1 -y 1} N semiconductor layer, and a voltage is applied to the first electrode and the second electrode. Is applied to cause the phosphor in the Al _x1 By ₁ Ga _1-x1-y1 N semiconductor layer to emit light.

In a preferred aspect of the present invention, the luminous body
But CaWO_Four, Gd_TwoO_TwoS: Tb, In_TwoO_Three, La_TwoO
_TwoS: Tb, MgSiO_Three: Mn, Y_TwoO_TwoS: Eu, Y_Two
O_TwoS: Tb, Y_TwoO_Three: Eu, Y_TwoSiO_Five: Ce, Y
_Three(Al, Ga)_FiveO₁₂: Ce, Y _ThreeAl_FiveO₁₂: Ce, Y
_ThreeAl_FiveO₁₂: Tb, YVO_Four: Eu, Zn_TwoSiO_Four: M
n, Zn_Three(PO_Four)_Two: Mn, ZnO: Zn, ZnS:
Ag, ZnS: Al, ZnS: Au, ZnS: Cu, Z
nS: Mn, (Zn, Cd) S: Al, (Zn, Cd)
S: Cu, (Zn, Cd) S: Au or a mixture thereof
It is characterized by being selected from objects.

As described above, the present invention is characterized by adding a phosphor to the semiconductor layer itself. When a high voltage is applied to the semiconductor layer, electrons are caused to transition in the phosphor added to the semiconductor layer, and light emission is caused accordingly. Therefore, it is much simpler than the conventional element structure. Further, the light emitting device of the present invention has excellent luminance and reproducibility of characteristics.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The present invention relates to Al_xB_yGa_1-xyN semiconductor layer
To the Al,_xB_yGa_1-xyN semiconductor layer
Injecting electrons and holes into the phosphor to cause the phosphor to emit light.
It is a light emitting element characterized by the following. The phosphor is a luminescent element of the present invention.
Although it is not particularly limited as long as it is suitable for the child, CaW
O_Four, Gd_TwoO_TwoS: Tb, In_TwoO_Three, La_TwoO_TwoS: T
b, MgSiO_Three: Mn, Y_TwoO_TwoS: Eu, Y_TwoO_TwoS:
Tb, Y_TwoO_Three: Eu, Y_TwoSiO_Five: Ce, Y_Three(Al,
Ga)_FiveO₁₂: Ce, Y_ThreeAl_FiveO₁₂: Ce, Y_ThreeAl _FiveO
₁₂: Tb, YVO_Four: Eu, Zn_TwoSiO_Four: Mn, Zn_Three
(PO_Four)_Two: Mn, ZnO: Zn, ZnS: Ag, Zn
S: Al, ZnS: Au, ZnS: Cu, ZnS: M
n, (Zn, Cd) S: Al, (Zn, Cd) S: Cu
And using a phosphor such as (Zn, Cd) S: Au.
Can be In the example of the above phosphor,
Descriptions such as A: B represent A with B added. For example
Gd_TwoO_TwoS: If Tb, Gd added with Tb_TwoO_TwoS
Means Addition of phosphor with such additives
The amount of the substance is as well known to those skilled in the art. Preferred of the present invention
Phosphors have the composition ratios shown in Table 1.

[0013]

[Table 1]

The phosphor is added in an amount sufficient to cause light emission. Specifically, although it depends on the phosphor used, it is preferable to add, for example, an amount of about 10 ¹⁷ to 10 ²¹ cm ^-3 . Al _{x By y} Ga to which this phosphor is added
_{A 1-xy} N semiconductor layer is grown, for example, on a substrate by metal organic chemical vapor deposition. _{Al x B y Ga 1-xy} N
The thickness of the semiconductor layer is preferably from 0.1 to 10 μm.

The composition ratio of _{Al x B y Ga 1-xy} N semiconductor layer is preferably 0 ≦ x ≦ 1,0 ≦ y ≦ 1, x + y ≦ 1.

Electrons and holes are injected into such a light emitting element to cause the phosphor to emit light. The injection of electrons and holes is
Conventional methods can be used.

In a preferred embodiment of the present invention, for example, a phosphor-added Al _x B _y grown on a substrate as described above.
A Ga _1-xy N semiconductor layer is sandwiched between electrodes, and a high voltage is applied to this semiconductor layer. As the voltage, 50 V to 5 kV can be used. By applying such a high voltage, electrons are caused to transition in the phosphor added to the semiconductor layer, and light emission is caused accordingly. As described above, the luminous body having the structure in which the Al _x B _y Ga _{1 -xy} N semiconductor layer to which the phosphor is added, which is grown on the substrate, is sandwiched between the electrodes, the electron and the positive electrode at the interface between the electrode and the semiconductor layer. Since holes can be injected, light emission mainly occurs at the interface between the electrode and the semiconductor layer.

The emitted light is applied to one of the electrodes by transparent ITO.
It can be extracted by using a conductive layer such as a film.

In a further preferred embodiment of the present invention, Al _x
The B _y Ga _1-xy N semiconductor layer, provided between the n-type semiconductor layer and the p-type semiconductor layer of AlBGaN system. In the light emitting element thus configured, by applying a positive voltage to the n-type semiconductor layer and applying a negative voltage to the p-type semiconductor layer, electrons and holes are respectively transferred from the n-type semiconductor layer and the p-type semiconductor layer. Is injected, and the entire semiconductor layer to which the phosphor is added can emit light.

The electrodes, substrates and the like of the light emitting device of the present invention may be made of the same materials as used in the conventional light emitting device, and the thickness and the like may be the same as those of the conventional light emitting device. For example, as the substrate, either an n-type substrate or a p-type substrate can be used. For example, as a substrate, Si (11
1), 6H-SiC (0001), sapphire (000
A material such as 1) (n-type substrate) or a substrate obtained by doping silicon with boron (p-type substrate) can be used. As the electrode, metal, for example, Ti, Ni, Au, etc.
Alternatively, an ITO film of a tin compound such as tin oxide or the like can be used. In addition, their thickness is 100 mm or more.
It can be 0.1 μm. Further, the electrodes can be grown by such means as evaporation.

As described above, the light-emitting device of the present invention has a structure which is extremely simpler than that of the conventional device by eliminating the need for members such as spacers by adding a phosphor to the semiconductor layer itself. It is simple. In addition, the light-emitting element of the present invention is an element having no variation in luminance and the like and excellent in reproducibility of light-emitting characteristics.

[0022]

The light emitting device of the present invention can be manufactured more easily than conventional devices by adding a phosphor to the semiconductor layer itself. As a result, reproducibility, which was poor in the conventional element structure, can be significantly improved.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. The following examples are exemplifications and do not limit the present invention.

(Embodiment 1) This embodiment will be described with reference to FIGS. FIG. 1 shows a first embodiment of the light emitting device of the present invention. FIG. 1A is a schematic diagram illustrating a cross-sectional structure of a light emitting element when an n-type substrate is used, and FIG.
FIG. 4 is a schematic diagram showing a state of light emission of this light emitting element. FIG. 1C is a schematic diagram illustrating a cross-sectional structure and light emission of a light emitting element when a p-type substrate is used. FIG.
It is a schematic diagram of a manufacturing process of the optical element of the present embodiment. As shown in FIG. 1, the light-emitting element of the present invention can use either an n-type substrate or a p-type substrate.

First, a light emitting element using an n-type substrate will be described with reference to FIG.

As shown in FIG. 1A, an optical element according to the present invention comprises a semiconductor layer 1 on a substrate 11 to which a phosphor is added.
2 are provided, and these layers (hereinafter also referred to as light-emitting portions) are sandwiched between the first electrode 13 and the second electrode 14.

The present invention is characterized in that a phosphor is added to the semiconductor layer 12 itself. The phosphor is not particularly limited as long as it is compatible with the light emitting device of the present invention, and the phosphors shown in Table 1 can be used.
The phosphor is added in an amount sufficient to cause light emission.
For example, in the case of the present embodiment (ZnS: Ag), 10 ¹⁹ cm
Add the amount of ^-3 . Further, the composition ratio of _{Al x B y Ga 1-xy} N semiconductor layer is preferably 0 ≦ x ≦ 1,0 ≦ y ≦ 1, x + y ≦ 1. In this embodiment, x = 0.8, y =
0.1.

The substrate 11 is made of 6H-Si which is a conductive material.
C (0001) was used. This substrate is an n-type substrate. The thickness of the substrate may be 350 μm.

In this embodiment, the first electrode 13 is made of Al _x
On B _y Ga _1-xy N semiconductor layer 12, second electrode 14,
Each of them is provided on the back side of the substrate 11 and is created by means such as vapor deposition. Note that the second electrode 14 may be provided on an end surface of the substrate. The thickness of the electrode is 100 ° -0.1 μm
Should be fine.

As shown in FIG. 1B, a positive voltage is applied to the second electrode 14 and a negative voltage is applied to the first electrode 13. As a result, electrons and holes are injected from the substrate 11 and the first electrode 13, respectively. In this embodiment, since electrons and holes can be injected at the interface between the electrode and the substrate and the semiconductor layer, light emission mainly occurs at the interface between the electrode and the substrate and the semiconductor layer. The applied voltage is between 0 and 2.5 kV. The semiconductor layer 12 emits light due to the transition of electrons in the phosphor, and the emitted light is extracted to the outside through the first electrode 13. First electrode 13
Is preferably transparent in order to extract emitted light. The transparency may be 50% or more. First electrode 13
Can be formed of a metal such as Ni or an oxide film such as tin oxide (for example, an ITO film). Second electrode 1
4 can use Ti and the like.

FIG. 1C shows an example using a p-type substrate. In the case of the present embodiment, the substrate 11 can be made of silicon doped with boron. The thickness of the substrate may be 350 μm.

As shown in this figure, the second electrode 14
And a positive voltage is applied to the first electrode 13. As a result, holes and electrons are injected from the substrate 11 and the first electrode 13, respectively. In this embodiment, injection of porosity and electrons can be caused at the interface between the electrode and the substrate and the semiconductor layer, so that light emission mainly occurs at the interface between the electrode and the substrate and the semiconductor layer. The applied voltage is
0 to 2.5 kV. The semiconductor layer 12 emits light due to the transition of electrons in the phosphor, and the emitted light is extracted to the outside through the first electrode 13. The first electrode 13 is
It is preferably transparent in order to extract emitted light. The transparency may be 50% or more. First electrode 13
Can be formed of a metal such as Ti or an oxide film such as tin oxide (for example, an ITO film). Second electrode 1
4 can use Ni or the like.

FIG. 1B and FIG.
The light emitting element shown in FIG. 1C shows an example in which light is extracted from the first electrode 13 side. However, the present invention is not limited to this, and the transparent substrate 11 may be used and the transparent electrode 14 may be used. Alternatively, by providing an electrode on the end face of the substrate, light can be extracted from the substrate 11 side. Further, in the present invention, light can be extracted from the end face of the semiconductor layer 12.

Hereinafter, the manufacturing process of the light emitting device of this embodiment shown in FIG. 1A will be described in detail with reference to FIG. In this embodiment, a manufacturing method using ZnS: Ag shown in Table 1 will be described.

First, a substrate (material 6H-SiC (000
1), 350 μm thick) 11 on which phosphor ZnS: Ag
Was added ^{_{10 19 cm -3 Al x B y}} Ga 1-xy N (x =
(0.8, y = 0.1) The semiconductor layer 12 is grown to a thickness of 1 μm by metalorganic vapor phase epitaxy to form a light emitting portion (FIG. 2A). _{Then, Al x B y Ga 1-} xy N
An electrode 13 such as a metal or an oxide film (tin oxide) such as an ITO film is deposited on the semiconductor layer 12 (FIG. 2B). Further, the back surface of the substrate 11, i.e., _{Al x B y Ga 1-xy} N reverse surface to the semiconductor layer 12 or electrode 14 to the end surface of the substrate 11,
(Material: Ti) is deposited (FIG. 2C). The thickness of the electrode is as described in the above description of the light-emitting element. In addition,
FIG. 2C shows an example in which the electrode 14 is deposited on the entire back surface of the substrate. Further, a device or the like for applying a voltage is provided to manufacture the light emitting device of the present invention (FIG. 2).
(D)).

As shown in FIG. 2D, a voltage is applied. As a result, electrons and holes are injected from the substrate 11 and the first electrode 13, respectively. In this embodiment, since injection of electrons and holes can be generated at the interface between the electrode and the substrate and the semiconductor layer, light emission mainly occurs at the interface between the electrode and the substrate and the semiconductor layer. This light is applied to the electrode 13
Is taken out to the outside. The electrode 13 is transparent for extracting emitted light. The transparency may be 50% or more. In the present embodiment, an example in which light is extracted from the side of the first electrode 13 has been described. However, the present invention is not limited to this, and the transparent substrate 11 and the transparent electrode 14 may be used.
Alternatively, by providing electrodes on the end face of the substrate,
It is also possible to extract light from the side. Further, in the present invention, light can be extracted from the end face of the semiconductor layer 12.

When the emission spectrum of the light emitting device manufactured according to this example was measured, the emission wavelength was 450 nm.

Various phosphors were added to the semiconductor layer 12, and the emission spectrum of the light emitting device of this example was measured. Various phosphors added to the semiconductor layer 12 and their emission peak wavelengths are as shown in Table 2.

[0039]

[Table 2]

The light emission characteristics were compared with those of a conventional light emitting device. The results are shown in FIG. 5 together with the results of the light emitting element shown in Example 2 (FIGS. 3 and 4) described later. In the conventional device, the luminance at 2.5 kV was 150 cd / m ² , but in the device of Example 1, the luminance was 5 × 10 ⁴ cd / m ² , and the luminance was increased 3.3 × 10 ² times. did. Also, with respect to the reproducibility of characteristics, the variation in luminance, which was 30% in the related art, was dramatically improved to 1% in the device of Example 1.

(Embodiment 2) This embodiment will be described with reference to FIGS.

FIG. 3 shows a second embodiment of the light emitting device of the present invention. FIG. 3A is a schematic diagram illustrating a cross-sectional structure of a light-emitting device when an n-type substrate is used, and FIG. 3B is a schematic diagram illustrating a state of light emission of the light-emitting device. FIG. 3 (c)
FIG. 3 is a schematic diagram illustrating a cross-sectional structure of a light-emitting element when a p-type substrate is used and a state of light emission of the light-emitting element. FIG. 4 is a schematic view illustrating a manufacturing process of the optical element of the present embodiment. In this embodiment, either an n-type substrate or a p-type substrate can be used.

[0043] As shown in FIG. 3 (a), the optical element of the present invention, the n-type _{Al x2 B y2 Ga 1-x2} -y2 N semiconductor layer 22 doped with an n-type impurity on the n-type substrate 21 provided, the _{Al x1 B y1 Ga 1-x1} -y1 N semiconductor layer 23 with the addition of emitters on this layer is provided, further a p-type Al was added p-type impurity _x2 B _y2 Ga _1-x2- this layer on _{A y2N} semiconductor layer 24 is provided, and the substrate 21 and the semiconductor layers 22 to 24 (hereinafter also referred to as light-emitting portions) are formed on the first electrode 25 and the second electrode 2.
6 between them.

The present invention is characterized in that a phosphor is added to the semiconductor layer 23 itself. The phosphor is not particularly limited as long as it is compatible with the light emitting device of the present invention, and the phosphors shown in Table 1 can be used.
The phosphor is added in an amount sufficient to cause light emission.
For example, in the case of the present embodiment (ZnS: Ag), 10 ¹⁹ cm
Add the amount of ^-3 . The composition ratio of the Al _{x1 By 1} Ga _1-x1-y1 N semiconductor layer 23 is 0 ≦ x1 ≦ 1, 0 ≦ y1 ≦ 1,
It is preferable that x1 + y1 ≦ 1. Al of the present embodiment
The composition ratio of _{x1 B y1 Ga 1-x1-} y1 N semiconductor layer 23, x1 =
0.7, y1 = 0.1.

In the present invention, the semiconductor layer 23 is sandwiched between the n-type semiconductor layer 22 and the p-type semiconductor layer 24. n-type Al _x2
The _{By2Ga1 -x2-y2N} semiconductor layer 22 is formed of n such as silicon.
For example, a type impurity is added by 10 ²⁰ cm ⁻³ .
The p-type semiconductor layer 24 contains a p-type impurity such as Mg,
For example, one added at 10 ¹⁹ cm ^-3 .

[0046] n-type _{Al x2 B y2 Ga 1-x2} -y2 N semiconductor layer 2
The composition ratio of 2 and p-type _{Al x B y Ga 1-xy} N semiconductor layer 24 is preferably 0 ≦ x2 ≦ 1,0 ≦ y2 ≦ 1, x2 + y2 ≦ 1. In the semiconductor layers 22, 23, and 24, the composition is x1 ≦ x2 and y1 ≦ y2. In this embodiment, the composition ratio of the n-type _{Al x2 B y2 Ga 1-x2} -y2 N semiconductor layer 22 and the p-type _{Al x2 B y2 Ga 1-x2} -y2 N semiconductor layer 24, x2 = 0.8, y2 = 0.1.
Each of the semiconductor layers 22, 23 and 24 has a thickness of 1 μm,
0.1 μm and 0.5 μm.

The n-type substrate 21 is made of 6H which is a conductive material.
-SiC (0001) can be used. The thickness of the substrate 21 is 300 to 400 μm.

In this embodiment, the first electrode 25 is an n-type A
On _{l x2 B y2 Ga 1-x2} -y2 N semiconductor layer 24, the second electrode 26 are respectively provided on the back side of the substrate 11, it is created by means such as evaporation. Note that the second electrode 26 may be provided on an end surface of the substrate 11. The thickness of these electrodes is 1
It is sufficient that the thickness is from 00 to 0.1 μm.

As shown in FIG. 3B, by applying a positive voltage to the second electrode 26 and a negative voltage to the first electrode 25, the semiconductor layer 22 and the semiconductor layer 24 are separated from each other. ,
Electrons and holes are injected into the semiconductor layer 23, respectively. The applied voltage is between 0 and 2.5 kV. When electrons and holes are injected into the semiconductor layer 23, the electrons move in the semiconductor layer 23, causing the electrons in the phosphor to transition, and the semiconductor layer 23 emits light. The emitted light is extracted outside through the p-type semiconductor layer 24 and the first electrode 25. The p-type semiconductor layer 24 and the first electrode 25 are preferably transparent in order to extract emitted light. The transparency may be 50% or more. First electrode 25
Can be formed of a metal such as Ni or an oxide film such as tin oxide (for example, an ITO film). Second electrode 2
6 can use Ti.

FIG. 3C shows an example using a p-type substrate. In the case of the present embodiment, the substrate 21 can be made of silicon doped with boron. The thickness of the substrate may be 300 to 400 μm.

When a p-type substrate is used, an n-type semiconductor layer 22 is provided on the first electrode 25 side and a p-type semiconductor layer 24 is provided on the substrate 21 side, unlike the case of using an n-type substrate. Can be

As shown in FIG. 3C, by applying a negative voltage to the second electrode 26 and a positive voltage to the first electrode 25, the semiconductor layer 22 and the semiconductor layer 24 are separated from each other. ,
Holes and electrons are injected into the semiconductor layer 23, respectively. The applied voltage is between 0 and 2.5 kV. When holes and electrons are injected into the semiconductor layer 23, the electrons move in the semiconductor layer 23, causing the electrons in the phosphor to transition, and the semiconductor layer 23 emits light. The emitted light is extracted outside through the n-type semiconductor layer 22 and the first electrode 25. The n-type semiconductor layer 22 and the first electrode 25 are preferably transparent to extract emitted light. The transparency may be 50% or more. First electrode 25
Is a metal such as Ti, an oxide film such as tin oxide (IT
O film). The second electrode 26 is N
i can be used.

In this embodiment, FIG.
Although an example in which light is extracted from the side of the first electrode 25 has been described, the present invention is not limited to this, and a transparent substrate 21, a transparent n-type semiconductor layer 22, and a transparent electrode 26 may be used. Is provided on the end face of the substrate, so that light can be extracted from the substrate 21 side. Further, in the present invention, light can be extracted from the end of the semiconductor layer 23 containing the phosphor. Further, in the light emitting device of FIG. 3C, light is emitted from the substrate 21 side by using the transparent substrate 21, the transparent p-type semiconductor layer 24, and the transparent electrode 26, or by providing the electrode on the end face of the substrate. It is also possible to take out. Further, in the present invention, light can be extracted from the end of the semiconductor layer 23 containing the phosphor.

In the present invention, the semiconductor layer 23 is sandwiched between the n-type and p-type semiconductor layers, so that the luminous efficiency of the light emitting section can be further increased.

Hereinafter, the manufacturing process of the light emitting device of this embodiment shown in FIG. 3A will be described in detail with reference to FIG.

First, a substrate (material: 6H-SiC (000
1), on the thickness 350μm) 21, 10 ²⁰ cm ^-3 the added n-type Si as n-type impurity _{Al x2 B y2 Ga 1-x2} -y2
An N (x2 = 0.8, y2 = 0.1) semiconductor layer 22 was grown to a thickness of 1 μm by metalorganic vapor phase epitaxy (FIG. 4A).

Next, on the n-type _{Al x2 B y2 Ga 1-x2} -y2 N semiconductor layer 22, the phosphor ZnS: Ag was added ^{_{10 19 cm -3 Al x1 B y1}} Ga 1-x1-y1 N (X = 0.7, y =
0.1) The semiconductor layer 23 was grown to a thickness of 0.1 μm by the metalorganic vapor phase epitaxial method (FIG. 4B).

Next, the phosphor-added Al _{x1 By 1} Ga
_1-x1-y1 N on the semiconductor layer 23, 10 ¹⁹ cm ^-3 the added p-type Mg as p-type impurity _{Al x2 B y2 Ga 1-x2} -y2 N
(X2 = 0.8, y2 = 0.1) The semiconductor layer 24 was grown to a thickness of 0.5 μm by metalorganic vapor phase epitaxy (FIG. 4C). Thus, the light emitting section of this example was formed.

[0059] p-type _{Al x2 B y2 Ga 1-x2} -y2 N semiconductor layer 2
An electrode 25 such as a metal or an oxide film (tin oxide) such as an ITO film is deposited on the substrate 4. Further, the back surface of the substrate 21, ie, n
An electrode 26 is deposited on the surface opposite to the mold semiconductor layer 22 or on the end surface of the substrate 21 (FIG. 4D). FIG. 4D shows an example in which the electrode 26 is deposited on the entire back surface of the substrate.
The thickness of each electrode is as described in the description of the light emitting element of Example 2 above.

Further, a device or the like for applying a voltage is provided to manufacture the light emitting device of the present invention (FIG. 4).
(E)).

As shown in FIG. 4E, the second electrode 26
By applying a positive voltage to the first electrode 25 and a negative voltage to the first electrode 25, electrons and holes are injected from the semiconductor layers 22 and 24 into the semiconductor layer 23, respectively. By injecting electrons and holes into the semiconductor layer 23, the semiconductor layer 2
The transfer of electrons occurs in 3, causing the electrons in the phosphor to transition, and the semiconductor layer 23 emits light. This light is applied to the p-type semiconductor layer 2
The electrode 4 passes through the electrode 25 and is taken out. The p-type semiconductor layer and the electrode 25 are transparent to extract emitted light. The transparency may be 50% or more.

In this embodiment, an example has been described in which light is extracted from the first electrode 25 side, but the present invention is not limited to this.
Light can be extracted from the substrate 21 side by using the transparent substrate 21, the transparent n-type semiconductor layer 22, and the transparent electrode 26, or by providing an electrode on an end surface of the substrate. Further, in the present invention, light can be extracted from the end of the semiconductor layer 23 containing the phosphor.

When the emission spectrum of the light emitting device manufactured according to this example was measured, the emission wavelength was 450 nm.

Various light emitters were added to the semiconductor layer 23, and the emission spectrum of the light emitting device was measured. Al _{x1 By 1} Ga
Various phosphors added to the _1-x1-y1 N semiconductor 23 and their emission peak wavelengths are as shown in Table 2 above.

The light emission characteristics were compared with those of a conventional light emitting device. The result is shown in FIG. 5 together with the result of the light emitting element shown in Example 1. In the conventional device, the luminance at 2.5 kV was 150 cd / m ² , but in the device of Example 2, it was 5.5 × 10 ⁴ cd / m ² , and the luminance was 3.7 × 10 ² times. Improved. Regarding the reproducibility of the characteristics, the variation of the luminance which was 30% in the related art was 0.1% in the device of Example 2.
It has improved dramatically by 5%. Further, in the present embodiment, since the n-type semiconductor layer 22 and the p-type semiconductor layer 24 are provided, electrons and holes can be efficiently injected into the semiconductor layer 23 to which the phosphor is added. The luminance and the reproducibility of the characteristics can be further improved as compared with the light emitting element having no light emitting element (Example 1).

[0066]

According to the light emitting device of the present invention, the phosphor can be added to the semiconductor layer itself, so that the device can be manufactured more easily than the conventional device.

Further, in the light emitting device of the present invention, the reproducibility, which was poor in the conventional device structure, can be remarkably improved, and the luminance has been greatly improved as compared with the conventional device.

In a preferred embodiment of the present invention, an n-type semiconductor layer and a p-type semiconductor layer can be provided in the light emitting portion of the light emitting device. By providing such a layer, the reproducibility of luminance and characteristics can be further improved.

[Brief description of the drawings]

FIG. 1A is a schematic diagram illustrating a cross-sectional structure of a light-emitting element of one embodiment of the present invention using an n-type substrate. (B)
3A is a schematic diagram illustrating a state of light emission of the light emitting element of FIG. (C) is a schematic diagram showing the cross-sectional structure and light emission of the solar light emitting device of the present invention using p as another substrate.

FIG. 2 is a schematic view illustrating a manufacturing process of the optical element of FIG.

FIG. 3A is a schematic diagram illustrating a cross-sectional structure of a light-emitting element according to another embodiment of the present invention using an n-type substrate.
(B) is a schematic diagram showing a state of light emission of the light emitting element of (a). (C) is a schematic diagram showing a cross-sectional structure and light emission of a light-emitting element of another embodiment of the present invention using a p-type substrate.

FIG. 4 is a schematic view showing a manufacturing process of the optical element of FIG.

FIG. 5 is a graph showing light emitting characteristics of the light emitting device of the present invention and a conventional light emitting device.

FIG. 6 is a schematic view illustrating a manufacturing process of a conventional light emitting device.

[Explanation of symbols]

11 substrate 12 Al and the phosphor was added _x B _y Ga _1-xy N semiconductor layer 13 electrode 14 electrode 21 substrate 22 n-type _{Al x2 B y2 Ga 1-x2} -y2 Al added with N semiconductor layer 23 phosphor _x1 B _y1 Ga _1-x1-y1 N semiconductor layer 24 p-type Al _x2 B _y2 Ga _1-x2-y2 N semiconductor layer 25 electrode 26 electrode 41 substrate 42 GaN semiconductor layer 43 electrode 44 insulating spacer 45 phosphor 46 ITO film (transparent Electrode) 47 Glass plate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09K 11/68 CQC C09K 11/68 CQC 11/78 CPB 11/78 CPB CPM CPM 11/79 CPR 11/79 CPR 11/83 CPB 11/83 CPB 11/84 CPD 11/84 CPD H05B 33/14 H05B 33/14 Z F term (reference) 3K007 AB02 AB03 AB18 CA00 CB01 DA02 DB02 DC01 DC02 DC04 FA01 4H001 CA04 XA08 XA12 XA13 XA14 XA15 XA16 XA20 XA23 XA30 XA31 XA39 XA48 XA49 XA57 XA64 XA74 YA13 YA25 YA29 YA30 YA47 YA58 YA63 YA65 YA79 5F041 AA04 AA11 AA42 CA34 CA40 CA46 CA65 FF01 FF11 FF16

Claims (4)

[Claims] 1. A _{Al x B y Ga 1-xy} N semiconductor layers (however,
(0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1), a phosphor is added, and electrons and holes are injected into the Al _x B _y Ga _1-xy N semiconductor layer to cause the phosphor to emit light. A light-emitting element, comprising: 2. A light emitting device comprising a light emitting part formed between the first electrode and the second electrode, the light emitting portion on a conductive substrate _{Al x B y Ga 1-xy} N A semiconductor layer (provided that 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1) is provided, and a phosphor is added to the Al _x B _y Ga _1-xy N semiconductor layer; emitting element for causing said _{Al x B y Ga 1-xy} N the phosphor to emit light in the semiconductor layer by applying a voltage to the first electrode and the second electrode. 3. A shape between a first electrode and a second electrode.
A light-emitting element comprising:
Part is p-type Al on the conductive substrate_x2B_y2Ga _1-x2-y2N
Semiconductor layer and n-type Al_x2B_y2Ga_1-x2-y2N semiconductor layer
(However, 0 ≦ x2 ≦ 1, 0 ≦ y2 ≦ 1, x2 + y2 ≦
Al sandwiched by 1)_x1B_y1Ga_{1-x1-y 1}N semiconductor layer
(However, 0 ≦ x1 ≦ 1, 0 ≦ y1 ≦ 1, x1 + y1 ≦
1) having a structure provided with:_x1B_y1Ga_1-x1-y1
A phosphor is added to the N semiconductor layer, and the first electrode and the second
By applying a voltage to the two electrodes,_x1B_y1G
a_{1-x1 -y1}Special feature is to make the phosphor in the N semiconductor layer emit light.
Light emitting element. 4. The light-emitting body is made of CaWO ₄ , Gd ₂ O.
₂ S: Tb, In ₂ O ₃ , La ₂ O ₂ S: Tb, MgSi
O ₃ : Mn, Y ₂ O ₂ S: Eu, Y ₂ O ₂ S: Tb, Y
₂ O ₃ : Eu, Y ₂ SiO ₅ : Ce, Y ₃ (Al, Ga) ₅ O
₁₂ : Ce, Y ₃ Al ₅ O ₁₂ : Ce, Y ₃ Al ₅ O ₁₂ : Tb,
YVO ₄ : Eu, Zn ₂ SiO ₄ : Mn, Zn ₃ (P
O ₄ ) ₂ : Mn, ZnO: Zn, ZnS: Ag, ZnS:
Al, ZnS: Au, ZnS: Cu, ZnS: Mn,
(Zn, Cd) S: Al, (Zn, Cd) S: Cu,
4. The light emitting device according to claim 1, wherein the light emitting device is selected from (Zn, Cd) S: Au and a mixture thereof.