阅读说明：本技术 发光二极管及其制作方法以及显示屏 (Light emitting diode, manufacturing method thereof and display screen ) 是由 杨顺贵 林雅雯 黄嘉宏 黄国栋 于 2020-08-12 设计创作，主要内容包括：本发明公开一种发光二极管,其包括：依次层叠设置的第一接触电极、第一半导体层、发光层、第二半导体层、电流扩散层以及第二接触电极；多个微结构,沿所述发光层和所述第二半导体层的层叠方向贯穿所述发光层和所述第二半导体层,每个所述微结构均开设有钻孔空间,所述钻孔空间的相对两端分别由所述第一半导体层和所述电流扩散层封闭；量子点,填充于多个所述微结构的所述钻孔空间内。通过该微结构发射的部分蓝光对所述量子点激发出相应颜色的光线,从而使得所述发光层可以混合出白光,此外,该微结构由于表面积效应将会提升色彩转换效率,进而提高全彩化效率。本发明还公开了一种发光二极管的制作方法以及一种显示屏。(The invention discloses a light emitting diode, which comprises: the light emitting diode comprises a first contact electrode, a first semiconductor layer, a light emitting layer, a second semiconductor layer, a current diffusion layer and a second contact electrode which are sequentially stacked; the microstructures penetrate through the light emitting layer and the second semiconductor layer along the stacking direction of the light emitting layer and the second semiconductor layer, each microstructure is provided with a drilling space, and two opposite ends of the drilling space are respectively sealed by the first semiconductor layer and the current diffusion layer; and the quantum dots are filled in the drilling spaces of the microstructures. Partial blue light emitted by the microstructure excites the quantum dots to emit light rays with corresponding colors, so that white light can be mixed in the light emitting layer. The invention also discloses a manufacturing method of the light emitting diode and a display screen.)

1. A light emitting diode, comprising:

the light emitting diode comprises a first semiconductor layer, a light emitting layer, a second semiconductor layer and a current diffusion layer which are sequentially stacked;

a first contact electrode in contact connection with the first semiconductor layer;

a second contact electrode in contact connection with the current diffusion layer;

the microstructures penetrate through the light emitting layer and the second semiconductor layer along the stacking direction of the light emitting layer and the second semiconductor layer, each microstructure is provided with a drilling space, and two opposite ends of the drilling space are respectively sealed by the first semiconductor layer and the current diffusion layer; and

and the quantum dots are filled in the drilling spaces of the microstructures.

2. The light-emitting diode according to claim 1, wherein each of the microstructures has a ring-shaped cross section, each of the microstructures includes a first bore and a second bore, the second bore has a size larger than that of the first bore, the second bore surrounds an outer side of the first bore and is spaced apart from the first bore by a predetermined distance, each of the first and second bores penetrates the second semiconductor layer and the light-emitting layer in the stacking direction, and opposite ends of the first and second bores are closed by the first semiconductor layer and the current diffusion layer, respectively.

3. The light-emitting diode according to claim 2, wherein the light-emitting layer comprises a plurality of quantum well layers and a plurality of quantum barrier layers, the plurality of quantum well layers and the plurality of quantum barrier layers being alternately stacked along the stacking direction.

4. The led of claim 3, wherein each of the microstructures further comprises a stopper wall formed between the first and second boreholes, each of the quantum well layers is interrupted by the microstructure, the portion of the quantum well layers disposed in the stopper wall forms a blue light indium gallium nitride quantum well layer, the portion of the quantum well layers disposed outside the microstructure forms a green light indium gallium nitride quantum well layer, and the quantum dots are red quantum dots.

5. The led of claim 2, wherein the first and second bores are any one of circular, square, rectangular, triangular, and diamond shaped bores.

6. The led of claim 3, wherein said quantum well layers are blue indium nitride gallium quantum well layers and said quantum dots are green quantum dots.

7. The led of claim 3, wherein the plurality of quantum well layers are indium nitride doped with al and the plurality of quantum barrier layers are gallium nitride layers; the current diffusion layer is made of a transparent conductive oxide thin film material, the first semiconductor layer is an n-type gallium nitride layer doped with silicon impurities, and the second semiconductor layer is made on the light emitting layer and is a p-type gallium nitride layer doped with magnesium impurities; the first contact electrode is an n-type ohmic contact electrode made of titanium or aluminum, the second contact electrode is made on the current diffusion layer and is a p-type ohmic contact electrode, and the second contact metal layer is made of nickel or gold.

8. A manufacturing method of a light emitting diode is characterized by comprising the following steps:

providing a base layer;

growing a first semiconductor layer on the base layer;

growing a light emitting layer on the first semiconductor layer;

growing a second semiconductor layer on the light emitting layer;

manufacturing a plurality of microstructures in the light emitting layer and the second semiconductor layer, and filling quantum dots in the microstructures;

sequentially growing a current diffusion layer and a second contact electrode on the second semiconductor layer and enclosing the quantum dots in the plurality of microstructures;

and removing the base layer, and plating a first contact electrode on the position of the first semiconductor layer corresponding to the base layer.

9. The method according to claim 8, wherein the light emitting layer includes a plurality of quantum well layers and a plurality of quantum barrier layers, the plurality of quantum well layers and the plurality of quantum barrier layers are alternately stacked, and the step of forming a plurality of microstructures in the light emitting layer and the second semiconductor layer and filling quantum dots in the microstructures comprises:

forming a first drilling hole penetrating through the light emitting layer and the second semiconductor layer along the laminating direction of the light emitting layer and the second semiconductor layer;

forming a second drilling hole penetrating through the light emitting layer and the second semiconductor layer along the stacking direction of the light emitting layer and the second semiconductor layer, wherein the second drilling hole surrounds the outer side of the first drilling hole and is spaced from the first drilling hole by a preset distance;

and filling the quantum dots in the first drilling hole and the second drilling hole.

10. A display screen, comprising a display panel and a plurality of light emitting diodes according to any one of claims 1 to 7, wherein the plurality of light emitting diodes are fixed on the display panel and electrically connected to the display panel.

Technical Field

The present disclosure relates to the field of semiconductor technologies, and in particular, to a light emitting diode, a method for manufacturing the light emitting diode, and a display panel having the light emitting diode.

Background

A Light Emitting Diode (LED) is a semiconductor device capable of converting electrical energy into Light energy, and a general LED structure includes an epitaxial substrate, a Light Emitting unit formed on the epitaxial substrate, and an electrode unit capable of providing electrical energy to the Light Emitting unit. Currently, gallium nitride-based LEDs are receiving more and more attention and research, for example, the light emitting unit is obtained by growing gallium nitride on an Epitaxial substrate made of sapphire in an Epitaxial (Epitaxial) manner. Therefore, the display screen with the LED has mature development in the aspects of materials, manufacturing procedures, equipment and the like, has wider application field, and is a next-generation flat panel display technology with higher feasibility.

At present, there are two main methods for applying the above LED to a display screen: (1) natural color mixing using RGB LEDs; (2) quantum dots (quantum dots) + blue LEDs. However, when the method (1) is used, the circuit design of the display panel of the display screen is difficult; when the method (2) is used, the color conversion efficiency of quantum dots is generally low, and the full-color efficiency is low. Therefore, how to solve the color conversion efficiency of quantum dots is always the direction of the development of the industry.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present application aims to provide an epitaxial substrate, a light emitting diode and a method for manufacturing the light emitting diode, which aims to solve the problems of difficult circuit design of a display panel and low quantum dot color conversion efficiency in the prior art.

A light emitting diode comprising: the LED display device comprises a first contact electrode, a first semiconductor layer, a light emitting layer, a second semiconductor layer, a current diffusion layer and a second contact electrode which are sequentially stacked, wherein the first contact electrode is in contact connection with the first semiconductor layer, and the second contact electrode is in contact connection with the current diffusion layer; the microstructures penetrate through the light emitting layer and the second semiconductor layer along the stacking direction of the light emitting layer and the second semiconductor layer, each microstructure is provided with a drilling space, and two opposite ends of the drilling space are respectively sealed by the first semiconductor layer and the current diffusion layer; and the quantum dots are filled in the drilling spaces of the microstructures.

In the light emitting diode, the corresponding quantum dots are filled in the drilling hole space formed in the microstructure, and part of blue light emitted by the microstructure excites the quantum dots to emit light rays with corresponding colors, such as red light or green light, so that the light emitting layer can be mixed with white light. In addition, the quantum dots are filled in the drilling hole space of the microstructure, so that the color conversion efficiency of the microstructure can be improved due to the surface area effect, and the full-color efficiency is further improved.

Optionally, each of the microstructures is annular in cross section, each of the microstructures comprises a first bore and a second bore, the second bore has a size larger than that of the first bore, and the second bore surrounds the outside of the first bore and is spaced from the first bore by a predetermined distance; each of the first bore holes and each of the second bore holes penetrate the second semiconductor layer and the light emitting layer in the stacking direction, and opposite ends of the first bore hole and the second bore hole are respectively closed by the first semiconductor layer and the current diffusion layer.

Alternatively, the light emitting layer includes a plurality of quantum well layers and a plurality of quantum barrier layers, which are alternately stacked along the stacking direction.

Optionally, each of the microstructures further includes a stopper wall formed between the first borehole and the second borehole, each quantum well layer is interrupted by the microstructure, a part of the quantum well layers disposed in the stopper wall forms a blue indium gallium nitride quantum well layer, a part of the quantum well layers disposed outside the microstructure forms a green indium gallium nitride quantum well layer, and the quantum dots are red quantum dots which generate red light through excitation, and the red light combines with the blue light and the green light emitted by the quantum well layers in the microstructure to form white light.

Because partial quantum well layers are independently separated and arranged in the stop wall, the material stress existing in the microstructure is released, so that the emission wavelength of the partial quantum well layers arranged in the stop wall is blue-shifted to emit blue light, namely, the original green light wavelength is changed into a blue light waveband, the blue light indium gallium nitride quantum well layer is formed, the partial quantum well layers (namely, the green light indium gallium nitride quantum well layer) which are not arranged in the annular microstructure still emit green light, and the multi-wavelength emission is realized. Based on the arrangement of the microstructure, the material stress existing in the quantum well layer can be solved, so that the quantum confined stark effect caused by the material stress is relieved, and the recombination efficiency between electrons and current is improved.

Optionally, the first and second bores are any one of circular, square, rectangular, triangular and diamond bores.

Optionally, when the first bore and the second bore are both circular, the diameter dimension of the first bore is 1-3 microns and the diameter dimension of the second bore is 7-13 microns.

Optionally, the first bore is formed by laser drilling and the second bore is formed by laser sintering.

Optionally, the microstructure is in the shape of any one of a cylinder, a cube, a cuboid, and a triangular prism.

Alternatively, the shape of the stopper wall is any one of a hollow cylinder, a hollow cube, a hollow cuboid, and a hollow triangular prism.

Optionally, the quantum well layer is a blue indium gallium nitride quantum well layer, and the quantum dot is a green quantum dot, and the green quantum dot absorbs blue light to excite and generate corresponding green light.

Optionally, the multiple quantum well layers are indium gallium nitride layers doped with aluminum, and the multiple quantum barrier layers are gallium nitride layers; the current diffusion layer is made of a transparent conductive oxide thin film material, the first semiconductor layer is an n-type gallium nitride layer doped with silicon impurities, and the second semiconductor layer is made on the light emitting layer and is a p-type gallium nitride layer doped with magnesium impurities; the first contact electrode is an n-type ohmic contact electrode made of titanium or aluminum, the second contact electrode is made on the current diffusion layer and is a p-type ohmic contact electrode, and the second contact metal layer is made of nickel or gold.

Based on the same inventive concept, the present application further provides a method for manufacturing a light emitting diode, comprising:

providing a base layer; growing a first semiconductor layer on the base layer; growing a light emitting layer on the first semiconductor layer; growing a second semiconductor layer on the light emitting layer; manufacturing a plurality of microstructures in the light emitting layer and the second semiconductor layer, and filling quantum dots in the microstructures; sequentially growing a current diffusion layer and a second contact electrode on the second semiconductor layer and enclosing the quantum dots in the plurality of microstructures; and removing the base layer, and plating a first contact electrode on the position of the first semiconductor layer corresponding to the base layer.

In the light emitting diode formed by the above manufacturing method, the corresponding quantum dots are filled in the drilling hole space formed in the microstructure, and the quantum dots are excited by part of blue light emitted by the microstructure to emit light rays with corresponding colors, such as red light or green light, so that the light emitting layer can be mixed to emit white light. In addition, the quantum dots are filled in the drilling hole space of the microstructure, so that the color conversion efficiency of the microstructure can be improved due to the surface area effect, and the full-color efficiency is further improved.

Optionally, the light emitting layer includes a plurality of quantum well layers and a plurality of quantum barrier layers, and the plurality of quantum well layers and the plurality of quantum barrier layers are alternately stacked, wherein the fabricating a plurality of microstructures in the light emitting layer and the second semiconductor layer, and filling quantum dots in the microstructures includes:

forming a first drilling hole penetrating through the light emitting layer and the second semiconductor layer along the laminating direction of the light emitting layer and the second semiconductor layer; forming a second drilling hole penetrating through the light emitting layer and the second semiconductor layer along the stacking direction of the light emitting layer and the second semiconductor layer, wherein the second drilling hole surrounds the outer side of the first drilling hole and is spaced from the first drilling hole by a preset distance; and filling the quantum dots in the first drilling hole and the second drilling hole.

Optionally, each of the microstructures further includes a stopper wall formed between the first borehole and the second borehole, each quantum well layer is interrupted by the microstructure, a part of the quantum well layers disposed in the stopper wall forms a blue indium gallium nitride quantum well layer, a part of the quantum well layers disposed outside the microstructure forms a green indium gallium nitride quantum well layer, and the quantum dots are red quantum dots which generate red light through excitation, and the red light combines with the blue light and the green light emitted by the quantum well layers in the microstructure to form white light.

Because partial quantum well layers are independently separated and arranged in the stop wall, the material stress existing in the microstructure is released, so that the emission wavelength of the partial quantum well layers arranged in the stop wall is blue-shifted to emit blue light, namely, the original green light wavelength is changed into a blue light waveband, the blue light indium gallium nitride quantum well layer is formed, the partial quantum well layers (namely, the green light indium gallium nitride quantum well layer) which are not arranged in the annular microstructure still emit green light, and the multi-wavelength emission is realized. Based on the arrangement of the microstructure, the material stress existing in the quantum well layer can be solved, so that the quantum confined stark effect caused by the material stress is relieved, and the recombination efficiency between electrons and current is improved.

Optionally, the first and second bores are any one of circular, square, rectangular, triangular and diamond bores.

Optionally, the microstructure is in the shape of any one of a cylinder, a cube, a cuboid, and a triangular prism.

Optionally, the quantum well layer is a blue indium gallium nitride quantum well layer, and the quantum dot is a green quantum dot, and the green quantum dot absorbs blue light to excite and generate corresponding green light.

Based on the same inventive concept, the present application further provides a display screen, which includes a display panel and a plurality of the above light emitting diodes, wherein the plurality of the light emitting diodes are fixed on the display panel and electrically connected with the display panel.

In the display screen with the light emitting diode, the quantum dots with corresponding colors are filled in the drilling hole space formed in the microstructure, and part of blue light emitted by the microstructure excites the quantum dots with light rays with corresponding colors, such as red light or green light, so that the light emitting layer can be mixed to generate white light. In addition, the quantum dots are filled in the drilling hole space of the microstructure, so that the color conversion efficiency of the microstructure can be improved due to the surface area effect, the full-color efficiency is further improved, and the display screen has the characteristic of ultrahigh resolution.

Optionally, each of the microstructures is annular in cross section, each of the microstructures comprises a first bore and a second bore, the second bore has a size larger than that of the first bore, and the second bore surrounds the outside of the first bore and is spaced from the first bore by a predetermined distance; each of the first bore holes and each of the second bore holes penetrate the second semiconductor layer and the light emitting layer in the stacking direction, and opposite ends of the first bore hole and the second bore hole are respectively closed by the first semiconductor layer and the current diffusion layer.

Alternatively, the light emitting layer includes a plurality of quantum well layers and a plurality of quantum barrier layers, which are alternately stacked along the stacking direction.

Optionally, each of the microstructures further includes a stopper wall formed between the first borehole and the second borehole, each quantum well layer is interrupted by the microstructure, a part of the quantum well layers disposed in the stopper wall forms a blue indium gallium nitride quantum well layer, a part of the quantum well layers disposed outside the microstructure forms a green indium gallium nitride quantum well layer, and the quantum dots are red quantum dots which generate red light through excitation, and the red light combines with the blue light and the green light emitted by the quantum well layers in the microstructure to form white light.

Because partial quantum well layers are independently separated and arranged in the stop wall, the material stress existing in the microstructure is released, so that the emission wavelength of the partial quantum well layers arranged in the stop wall is blue-shifted to emit blue light, namely, the original green light wavelength is changed into a blue light waveband, the blue light indium gallium nitride quantum well layer is formed, the partial quantum well layers (namely, the green light indium gallium nitride quantum well layer) which are not arranged in the annular microstructure still emit green light, and the multi-wavelength emission is realized. Based on the arrangement of the microstructure, the material stress existing in the quantum well layer can be solved, so that the quantum confined stark effect caused by the material stress is relieved, and the recombination efficiency between electrons and current is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic cross-sectional view of a light emitting diode according to an embodiment of the present disclosure;

FIG. 2a is a schematic top view of the microstructure shown in FIG. 1 according to one embodiment;

FIG. 2b is a schematic top view of a microstructure of the alternative embodiment shown in FIG. 1;

FIG. 2c is a schematic top view of a microstructure according to yet another embodiment shown in FIG. 1;

FIG. 3 is a flowchart illustrating a method of fabricating the light emitting diode shown in FIG. 1;

FIGS. 4a-4g are schematic structural diagrams corresponding to steps in the manufacturing method shown in FIG. 3;

FIG. 5 is a detailed flowchart of step S10 in the manufacturing method of FIG. 3;

FIG. 6 is a detailed flowchart of step S50 in the manufacturing method of FIG. 3;

fig. 7 is a schematic cross-sectional structure view of a display screen using the light emitting diode according to an embodiment of the present application.

Description of reference numerals:

100-a light emitting diode;

10-a first contact electrode;

20-a first semiconductor layer;

30-a light-emitting layer;

31-a multi-layer quantum well layer;

31 a-green InGaN quantum well layer;

31 b-blue InGaN quantum well layer;

33-multiple quantum barrier layers;

50-a second semiconductor layer;

60-a current spreading layer;

70-a second contact electrode;

80-microstructure;

82-a first bore;

84-a second borehole;

85-stop wall;

86-quantum dots;

S10-S70-steps of the manufacturing method;

S11-S13-substep of step S10;

S51-S53-substep of step S50;

200-a display screen;

201-a sapphire substrate;

202-a buffer layer;

203-undoped gallium nitride layer;

210-a display panel;

212-positive electrode pad;

213-negative electrode pad.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

A general LED structure includes an epitaxial substrate, a light emitting unit formed on the epitaxial substrate, and an electrode unit capable of providing electric energy to the light emitting unit. Currently, gallium nitride-based LEDs are receiving more and more attention and research, for example, the light emitting unit is obtained by epitaxially growing gallium nitride on an epitaxial substrate made of sapphire. Therefore, the display screen with the LED has mature development in the aspects of materials, manufacturing procedures, equipment and the like, has wider application field, and is a next-generation flat panel display technology with higher feasibility. At present, there are two main methods for applying the above LED to a display screen: (1) natural color mixing using RGB LEDs; (2) quantum dots + blue LEDs. However, when the method (1) is used, the circuit design of the display panel of the display screen is difficult; when the method (2) is used, the color conversion efficiency of quantum dots is generally low, and the full-color efficiency is low.

Based on this, the present application intends to provide a solution to the above technical problem, the details of which will be explained in the following embodiments.

The present disclosure describes a layer structure of an epitaxial substrate in a light emitting diode and a specific process of a method for manufacturing the light emitting diode in detail.

Please refer to fig. 1, which is a schematic cross-sectional view of a light emitting diode according to an embodiment of the present disclosure. The light emitting diode 100 shown in fig. 1 is a gallium nitride (GaN) -based micro light emitting diode, and includes a first contact electrode 10, and a first semiconductor layer 20, a light emitting layer 30, a second semiconductor layer 50, a current diffusion layer 60, and a second contact electrode 70, which are sequentially stacked on the first contact electrode 10. The first contact electrode 10 is in contact with the first semiconductor layer 20, and the second contact electrode 70 is in contact with the current diffusion layer 60.

In this embodiment, the first contact electrode 10 may be an n-type ohmic contact electrode, and in some embodiments, the first contact electrode 10 may be made of a metal material such as titanium or aluminum. The second contact electrode 70 is formed on the current diffusion layer 60, and may be a p-type ohmic contact electrode, and in some embodiments, the second contact electrode 70 may be made of a metal material such as nickel, gold, or the like.

In this embodiment, the first semiconductor layer 20 may be a GaN layer formed on the first contact electrode 10, and the material thereof may be an n-type gallium nitride series III-V compound, and in some embodiments, the first semiconductor layer 20 may also be an n-type gallium nitride layer doped with silicon impurities. The second semiconductor layer 50 may be a GaN layer formed on the light emitting layer 30, and may be a p-type gallium nitride series III-V compound, and in some embodiments, the second semiconductor layer 50 may also be a p-type gallium nitride layer doped with magnesium impurities.

In some embodiments, the current spreading layer 60 may be made of a Transparent Conductive Oxide (TCO) thin film material with high transmittance and low resistivity in the visible spectrum. The TCO thin film material mainly comprises oxides such as CdO, In2O3, SnO2 and ZnO and corresponding compound multi-component semiconductor materials.

In the present embodiment, the light emitting layer 30 may be a light emitting layer, and specifically, may be formed by alternately stacking a plurality of quantum well layers 31 and a plurality of quantum barrier layers 33. In some embodiments, the quantum well layers 31 may be indium gallium nitride (InGaN) layers doped with aluminum (Al), and the quantum barrier layers 33 may be GaN layers. In this embodiment, the multiple quantum well layers 31 are green InGaN quantum well layers 31 a. The number of quantum well layers 31 in the light-emitting layer 30 may be 20.

In this embodiment, the light emitting diode 100 further includes a plurality of microstructures 80, and the plurality of microstructures 80 are disposed in the light emitting layer 30 and the second semiconductor layer 50 and located between the first semiconductor layer 20 and the current diffusion layer 60. The plurality of microstructures 80 penetrate the entire light emitting layer 30 in the stacking direction of the multiple quantum well layers 31. Illustratively, the plurality of microstructures 80 may also penetrate through the entire second semiconductor layer 50 in the stacking direction of the multiple quantum well layers 31.

Please refer to fig. 2a, which is a schematic top view of one of the microstructures 80 shown in fig. 1. As can be seen in fig. 2a, each microstructure 80 is annular in plan view, i.e. it comprises a first bore 82 and a second bore 84. The first bore 82 has the same center as the second bore 84, and the second bore 84 is larger in size than the first bore 82, i.e., the second bore 84 is located on the peripheral side of the first bore 82. In this embodiment, the first bore 82 and the second bore 84 are circular in cross section, and have the same center, and the radius of the second bore 84 is larger than that of the first bore 82, so that the first bore 82 and the second bore 84 form a circular ring shape in cross section.

For convenience of illustration and description of the positional relationship between the microstructure 80 and the light emitting layer 30 and the second semiconductor layer 50, please refer to fig. 1. Each of the first bore holes 82 penetrates the second semiconductor layer 50 and the light emitting layer 30 in the stacking direction of the plurality of quantum well layers 31, and opposite ends of the first bore hole 82 are respectively closed by the first semiconductor layer 20 and the current diffusion layer 60, that is, the plurality of first bore holes 82 are opened between the first semiconductor layer 20 and the current diffusion layer 60. Each second via hole 84 also penetrates the second semiconductor layer 50 and the light emitting layer 30 in the stacking direction of the plurality of quantum well layers 31, and opposite ends of the second via hole 84 are respectively closed by the first semiconductor layer 20 and the current diffusion layer 60. Also, the second bore 84 surrounds the outside of the first bore 82 and is spaced apart from the first bore 82 by a predetermined distance, and a plurality of second bores 84 are opened between the first semiconductor layer 20 and the current diffusion layer 60. Since the second bore 84 is spaced apart from the first bore 82 by a predetermined distance, a stop wall 85 is formed between the second bore 84 and the first bore 82, and the thickness of the stop wall 85 is the ring width of the ring-shaped microstructure 80. The stopper wall 85 is an annular wall formed by the light emitting layer 30 and the second semiconductor layer 50 in the extending direction of the first bore 82 and the second bore 84, and is used for separating the first bore 82 and the second bore 84, so that the material composition of the stopper wall 85 at the light emitting layer 30 and the second semiconductor layer 50 and the function thereof are not changed.

In the present embodiment, each of the quantum well layers 31 is partitioned into a plurality of different portions due to the presence of the first and second via holes 82 and 84. Specifically, a part of the quantum well layer 31 is located outside the microstructure 80, and another part of the quantum well layer 31 is independently disposed in the stopper wall 85, that is, the part of the quantum well layer 31 located outside the microstructure 80 is separated from the part of the quantum well layer 31 in the stopper wall 85 by the second drilling 84, and the part of the quantum well layer 31 in the stopper wall 85 is separated by the first drilling 82. In the above embodiment, since the partial quantum well layers 31 are independently separated and disposed in the stopper wall 85, the material stress existing in the microstructure 80 is released, so that the partial quantum well layers 31 disposed in the stopper wall 85 emit blue-shifted wavelength and emit blue light, i.e., change the original green wavelength into the blue wavelength band, to form the blue InGaN quantum well layer 31b, and the partial quantum well layers not disposed in the annular microstructure 80 (i.e., the green InGaN quantum well layer 31a) still emit green light, thereby realizing multi-wavelength emission. Based on the arrangement of the microstructure 80, the material stress existing in the Quantum well layer 31 can be solved, so that the Quantum Confined Stark Effect (QCSE) caused by the material stress is reduced, and the recombination efficiency between electrons and current is further improved.

In this embodiment, the led 100 further includes quantum dots 86 filled in the first and second bores 82 and 84. In the above embodiment, the quantum dots 86 may be filled in the first and second bores 82 and 84 by spraying using a spraying machine. In the present embodiment, the quantum dots 86 are red quantum dots that generate red light by excitation, and the red light combines with the blue light and the green light emitted from the quantum well layers 31 in the microstructure 80 to form white light.

It is understood that in some embodiments, the quantum dots 86 can also be green quantum dots, in which case, the green quantum dots are directly filled in the microstructures 80, and the quantum well layers 31 are blue indium gallium nitride quantum well layers capable of emitting blue light, and the green quantum dots absorb the blue light to excite green light with corresponding peak wavelength.

In summary, in the light emitting diode of the present application, the corresponding quantum dots 86 are filled in the drilling space formed in the microstructure 80, and a part of blue light emitted by the microstructure 80 excites the quantum dots 86 to emit red light or green light, so that the light emitting layer 30 can mix white light. In addition, the quantum dots 86 are filled in the drilling space of the microstructure 80, so that the color conversion efficiency of the microstructure 80 is improved due to the surface area effect, and the full-color efficiency is further improved.

In some embodiments, when the first and second bores 82, 84 are both circular in cross-section, the stop wall 85 may have a thickness of less than or equal to 5 micrometers (μm), such as 3-5 μm, and further such as 3 μm, 4 μm, 5 μm, or other thicknesses.

In some embodiments, the first bore 82 may be formed by laser drilling and the second bore 84 may be formed by laser sintering. The first and second bores 82 and 84 are any one of circular, square, rectangular, triangular, and diamond bores.

In some embodiments, the shape of the first bore 82 and the second bore 84 formed together in the cross-sectional direction thereof is not limited to a circular shape (as shown in fig. 2 a), and in some embodiments, may be a square ring shape (as shown in fig. 2 b), a triangular ring shape (as shown in fig. 2 c), a rectangular ring shape, or other shapes. Accordingly, the shape of the microstructure 80 may be cylindrical, square, rectangular, triangular prism, or other shapes as a whole. It is understood that the stopper wall 85 may have a hollow cylindrical shape, a hollow square shape, a hollow rectangular parallelepiped shape, a hollow triangular prism shape, or other shapes as a whole, that is, the stopper wall 85 may have a circular ring shape, a square ring shape, a rectangular ring shape, a triangular ring shape, or other shapes in its cross-sectional direction.

In some embodiments, when the first and second bores 82, 84 are both circular, the inner diameter of the microstructure 80 (i.e., the diameter of the first bore 82) can have a dimension less than or equal to 3 μm, such as 1-3 μm, for example, and again, such as 1 μm, 2 μm, 3 μm, or other dimensions. Accordingly, the outer diameter (i.e., the diameter of the second bore 84) dimension of the microstructure 80 may be less than or equal to 13 μm, such as 7-13 μm, for example, and further such as 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, or other dimensions.

Referring to fig. 3 and fig. 4a to 4g, fig. 3 is a specific flowchart of a method for manufacturing the light emitting diode shown in fig. 1, and fig. 4a to 4g are schematic structural diagrams corresponding to steps in the method shown in fig. 3. The light emitting diode 100 is a gallium nitride (GaN) -based micro light emitting diode, and includes a first contact electrode 10, and a first semiconductor layer 20, a light emitting layer 30, a second semiconductor layer 50, a current diffusion layer 60, and a second contact electrode 70 sequentially stacked on the first contact electrode 10. The first contact electrode 10 is in contact with the first semiconductor layer 20, and the second contact electrode 70 is in contact with the current diffusion layer 60. The manufacturing method at least comprises the following steps.

Step S10, providing a base layer;

specifically, as shown in fig. 4a, the base layer includes a sapphire substrate 201, a buffer layer 202 and an undoped gallium nitride (GaN) layer 203, which are sequentially stacked, wherein the buffer layer 202 is located between the sapphire substrate 201 and the undoped GaN layer 203. In some embodiments, the sapphire substrate 201 may be crystal-oriented sapphire, and the buffer layer 202 may be a GaN buffer layer, or may be a low temperature gallium nitride (LT-GaN) buffer layer.

In this embodiment, as shown in fig. 5, the step S10 includes the following sub-steps:

step S11, performing nitridation processing on the sapphire substrate 201;

it is understood that step S11 may clean the surface of the sapphire substrate 201.

Step S12, growing a buffer layer 202 on the sapphire substrate 201;

step S13, growing an undoped GaN layer 203 on the buffer layer 202.

In some embodiments, after the step S12, the method further includes: and carrying out in-situ annealing treatment on the buffer layer.

Step S20, growing a first semiconductor layer 20 on the base layer;

specifically, as shown in fig. 4b, the first semiconductor layer 20 is grown on the undoped GaN layer 203 of the base layer. In this embodiment, the first semiconductor layer 20 may be a GaN layer, and the material thereof may be an n-type gallium nitride series III-V compound, and in some embodiments, the first semiconductor layer 20 may also be an n-type gallium nitride layer doped with silicon impurities.

Step S30 of growing a light-emitting layer 30 on the first semiconductor layer 20;

specifically, as shown in fig. 4c, the light emitting layer 30 is grown on the first semiconductor layer 20. In the present embodiment, the light emitting layer 30 may be a light emitting layer, and specifically, may be formed by alternately stacking a plurality of quantum well layers 31 and a plurality of quantum barrier layers 33. In some embodiments, the quantum well layers 31 may be indium gallium nitride (InGaN) layers doped with aluminum (Al), and the quantum barrier layers 33 may be GaN layers. In this embodiment, the multiple quantum well layers 31 are green InGaN quantum well layers 31 a. The number of quantum well layers 31 in the light-emitting layer 30 may be 20.

Step S40 of growing a second semiconductor layer 50 on the light-emitting layer 30;

specifically, as shown in fig. 4d, the second semiconductor layer 50 is grown on the light emitting layer 30. In this embodiment, the second semiconductor layer 50 is formed on the light emitting layer 30, the second semiconductor layer 50 may be a GaN layer, and the material thereof may be a p-type gallium nitride series III-V compound, and in some embodiments, the second semiconductor layer 50 may also be a p-type gallium nitride layer doped with magnesium impurities.

Step S50, fabricating a plurality of microstructures 80 in the light emitting layer 30 and the second semiconductor layer 50, and filling quantum dots 86 in the microstructures;

specifically, as shown in fig. 4e, in the present embodiment, a plurality of microstructures 80 are disposed in the light emitting layer 30 and the second semiconductor layer 50, and the plurality of microstructures 80 penetrate through the entire light emitting layer 30 and the entire second semiconductor layer 50 along the stacking direction of the multiple quantum well layers 31. Each microstructure 80 is annular in plan view, i.e., it includes a first bore 82 and a second bore 84. The first bore 82 has the same center as the second bore 84, and the second bore 84 is larger in size than the first bore 82, i.e., the second bore 84 is located on the peripheral side of the first bore 82. In the present embodiment, as shown in fig. 2a, the cross-sections of the first bore 82 and the second bore 84 are circular, both have the same center, and the radius of the second bore 84 is larger than that of the first bore 82, so that the first bore 82 and the second bore 84 form a circular ring shape together on the cross-section. In some embodiments, the shape of the first bore 82 and the second bore 84 formed together in the cross-sectional direction thereof may also be a square ring shape (as shown in fig. 2 b), a triangular ring shape (as shown in fig. 2 c), a rectangular ring shape, or other shapes. Accordingly, the shape of the microstructure 80 may be cylindrical, square, rectangular, triangular prism, or other shapes as a whole.

Each first bore 82 penetrates the second semiconductor layer 50 and the light-emitting layer 30 in the lamination direction of the plurality of quantum well layers 31, and each second bore 84 also penetrates the second semiconductor layer 50 and the light-emitting layer 30 in the lamination direction of the plurality of quantum well layers 31. Also, the second bore 84 surrounds the outside of the first bore 82 and is spaced a predetermined distance from the first bore 82. Since the second bore 84 is spaced apart from the first bore 82 by a predetermined distance, a stop wall 85 is formed between the second bore 84 and the first bore 82, and the thickness of the stop wall 85 is the ring width of the ring-shaped microstructure 80. The stopper wall 85 is an annular wall formed by the light emitting layer 30 and the second semiconductor layer 50 in the extending direction of the first bore 82 and the second bore 84, and is used for spacing the first bore 82 and the second bore 84, and therefore, the material composition of the stopper wall 85 at the light emitting layer 30 and the second semiconductor layer 50 is not changed.

It is understood that the stopper wall 85 may have a hollow cylindrical shape, a hollow square shape, a hollow rectangular parallelepiped shape, a hollow triangular prism shape, or other shapes as a whole, that is, the stopper wall 85 may have a circular ring shape, a square ring shape, a rectangular ring shape, a triangular ring shape, or other shapes in its cross-sectional direction.

In the present embodiment, each of the quantum well layers 31 is partitioned into a plurality of different portions due to the presence of the first and second via holes 82 and 84. Specifically, a part of the quantum well layer 31 is located outside the microstructure 80, and another part of the quantum well layer 31 is independently disposed in the stopper wall 85, that is, the part of the quantum well layer 31 located outside the microstructure 80 is separated from the part of the quantum well layer 31 in the stopper wall 85 by the second drilling 84, and the part of the quantum well layer 31 in the stopper wall 85 is separated by the first drilling 82. In the above embodiment, since the partial quantum well layers 31 are independently separated and disposed in the stopper wall 85, the material stress existing in the microstructure 80 is released, so that the partial quantum well layers 31 disposed in the stopper wall 85 emit blue-shifted wavelength and emit blue light, that is, the original green wavelength is changed into the blue wavelength band, and the blue InGaN quantum well layer 31b is formed, while the partial quantum well layers (i.e., the green InGaN quantum well layer 31a) that are not disposed in the annular microstructure 80 still emit green light, thereby realizing multi-wavelength emission. Based on the arrangement of the microstructure 80, the material stress existing in the Quantum well layer 31 can be solved, so that the Quantum Confined Stark Effect (QCSE) caused by the material stress is reduced, and the recombination efficiency between electrons and current is further improved.

In the above embodiment, the quantum dots 86 may be filled in the first and second bores 82 and 84 by spraying using a spraying machine. In the present embodiment, the quantum dots 86 are red quantum dots that generate red light by excitation, and the red light combines with the blue light and the green light emitted from the quantum well layers 31 in the microstructure 80 to form white light.

It is understood that in some embodiments, the quantum dots 86 can also be green quantum dots, in which case, the green quantum dots are directly filled in the microstructures 80, and the quantum well layers 31 are blue indium gallium nitride quantum well layers capable of emitting blue light, and the green quantum dots absorb the blue light to excite green light with corresponding peak wavelength.

In this embodiment, as shown in fig. 6, the step S50 includes the following sub-steps:

a step S51 of opening a first via hole 82 penetrating the light-emitting layer 30 and the second semiconductor layer 50 in a direction in which the light-emitting layer 30 and the second semiconductor layer 50 are stacked;

step S52 of opening a second via hole 84 penetrating the light-emitting layer 30 and the second semiconductor layer 50 in a direction in which the light-emitting layer 30 and the second semiconductor layer 50 are stacked, wherein the second via hole 84 surrounds an outer side of the first via hole 82 and is spaced apart by a predetermined distance;

step S53, filling the quantum dots 86 in the first bore 82 and the second bore 84.

In some embodiments, when the first and second bores 82, 84 are both circular in cross-section, the stop wall 85 may have a thickness of less than or equal to 5 micrometers (μm), such as 3-5 μm, and further such as 3 μm, 4 μm, 5 μm, or other thicknesses.

In some embodiments, the first bore 82 may be formed by laser drilling and the second bore 84 may be formed by laser sintering. The first and second bores 82 and 84 are any one of circular, square, rectangular, triangular, and diamond bores.

In some embodiments, when the first and second bores 82, 84 are both circular, the inner diameter of the microstructure 80 (i.e., the diameter of the first bore 82) can have a dimension less than or equal to 3 μm, such as 1-3 μm, for example, and again, such as 1 μm, 2 μm, 3 μm, or other dimensions. Accordingly, the outer diameter (i.e., the diameter of the second bore 84) dimension of the microstructure 80 may be less than or equal to 13 μm, such as 7-13 μm, for example, and further such as 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, or other dimensions.

Step S60, sequentially growing a current diffusion layer 60 and a second contact electrode 70 on the second semiconductor layer 50 and enclosing the quantum dots 86 in the plurality of microstructures 80;

specifically, as shown in fig. 4f, a current spreading layer 60 and a second contact electrode 70 are sequentially grown on the second semiconductor layer 50 and the quantum dots 86 are enclosed in the plurality of microstructures 80. In some embodiments, the current spreading layer 60 may be made of a Transparent Conductive Oxide (TCO) thin film material with high transmittance and low resistivity in the visible spectrum. The TCO thin film material mainly comprises oxides such as CdO, In2O3, SnO2 and ZnO and corresponding compound multi-component semiconductor materials. In this embodiment, the second contact electrode 70 is formed on the current diffusion layer 60, and may be a p-type ohmic contact electrode, and in some embodiments, the second contact electrode 70 may be made of a metal material such as nickel or gold.

Step S70, removing the base layer, and plating a first contact electrode 10 on the first semiconductor layer 20 corresponding to the base layer.

Specifically, as shown in fig. 4g, after the current diffusion layer 60 and the second contact electrode 70 are sequentially grown on the second semiconductor layer 50, the underlayer is peeled off from the first semiconductor layer 20 by a Laser Lift Off (LLO) process to complete the peeling of the underlayer. Then, a first contact electrode 10 is plated on the original position of the base layer, that is, the first contact electrode 10 is plated on the side of the first semiconductor layer 20 opposite to the light-emitting layer 30, thereby completing the fabrication of the light-emitting diode 100.

In this embodiment, the first contact electrode 10 may be an n-type ohmic contact electrode, and in some embodiments, the first contact electrode 10 may be made of a metal material such as titanium or aluminum.

In the above embodiment, the growth method for the material in the above step mainly adopts Metal-organic Chemical Vapor Deposition (MOCVD) and Molecular Beam Epitaxy (MBE).

In summary, in the light emitting diode 100 formed by the manufacturing method of the present application, the corresponding quantum dots 86 are filled in the drilling space formed in the microstructure 80, and a part of blue light emitted by the microstructure 80 excites the quantum dots 86 to emit red light or green light, so that the light emitting layer 30 can mix white light. In addition, the quantum dots 86 are filled in the drilling space of the microstructure 80, so that the color conversion efficiency of the microstructure 80 is improved due to the surface area effect, and the full-color efficiency is further improved.

Please refer to fig. 7, which is a schematic cross-sectional structure diagram of a display panel using the light emitting diode according to an embodiment of the present application. In the present embodiment, the display panel 200 includes a display panel 210 and a plurality of the light emitting diodes 100, and the plurality of the light emitting diodes 100 are fixed on the display panel 210 and electrically connected to the display panel 210. When the display 200 is in operation, the corresponding quantum dots 86 are filled in the drilled holes formed in the microstructures 80, and a part of the blue light emitted by the microstructures 80 excites the quantum dots 86 with light rays of corresponding colors, such as red light or green light, so that the light emitting layer 30 can mix with white light, and then the display 200 can provide a white light source.

In some embodiments, the display panel 210 may be provided with a plurality of sets of positive and negative pads, which are exemplified in the present embodiment. In the present embodiment, each set of positive and negative electrode pads includes a positive electrode pad 212 and a negative electrode pad 213 spaced apart from each other. The first contact electrode 10 of each led 100 is in direct contact with the negative pad 213 to form an electrical connection therebetween, and the second contact electrode 70 of each led 100 is electrically connected with the positive pad 212.

In the above embodiment, the display 200 may be an Augmented Reality (AR) micro-display or a mobile/large-size display.

In summary, in the display panel 200 having the light emitting diode 100, the corresponding quantum dots 86 are filled in the drilling space formed in the microstructure 80, and a part of the blue light emitted by the microstructure 80 excites the quantum dots 86 to emit light of a corresponding color, such as red light or green light, so that the light emitting layer 30 can mix white light. In addition, the quantum dots 86 are filled in the drilling space of the microstructure 80, so that the color conversion efficiency of the microstructure 80 is improved due to the surface area effect, and the full-color efficiency is further improved, so that the display screen 200 has the characteristic of ultrahigh resolution.

It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.