阅读说明：本技术 铝镓氮基紫外led外延结构及紫外led灯 (Aluminum gallium nitrogen-based ultraviolet LED epitaxial structure and ultraviolet LED lamp ) 是由 李光 郑悠 白耀平 于 2019-09-19 设计创作，主要内容包括：本发明涉及一种铝镓氮基紫外LED外延结构及紫外LED灯,铝镓氮基紫外LED外延结构包括依次层叠设置的衬底、缓冲层、第一铝镓氮层、发光层以及第二铝镓氮层；第二铝镓氮层包括多个第二铝镓氮子层,多个第二铝镓氮子层依次层叠设置,多个第二铝镓氮子层的铝组分不同,与发光层连接的第二铝镓氮子层的铝组分大于其他第二铝镓氮子层的铝组分。靠近发光层的第二铝镓氮子层铝组分最大,远离发光层的第二铝镓氮子层铝组分最小,不同组分的第二铝镓氮子层,减弱了第二铝镓氮层的内建电场,使得第二铝镓氮层与发光层之间的压电极化效应减弱,从而提高空穴的有效注入率,使得电子与空穴的辐射复合率提高,提高了铝镓氮基紫外LED外延结构的内量子率和发光率。(The invention relates to an aluminum gallium nitrogen based ultraviolet LED epitaxial structure and an ultraviolet LED lamp, wherein the aluminum gallium nitrogen based ultraviolet LED epitaxial structure comprises a substrate, a buffer layer, a first aluminum gallium nitrogen layer, a luminous layer and a second aluminum gallium nitrogen layer which are sequentially stacked; the second AlGaN layer comprises a plurality of second AlGaN sublayers, the second AlGaN sublayers are sequentially stacked, the aluminum components of the second AlGaN sublayers are different, and the aluminum components of the second AlGaN sublayers connected with the light-emitting layer are larger than those of the other second AlGaN sublayers. The second AlGaN sublayer close to the luminescent layer has the largest aluminum component, the second AlGaN sublayer far away from the luminescent layer has the smallest aluminum component, and the second AlGaN sublayer with different components weakens the built-in electric field of the second AlGaN layer, so that the piezoelectric polarization effect between the second AlGaN layer and the luminescent layer is weakened, the effective injection rate of holes is improved, the radiation recombination rate of electrons and holes is improved, and the internal quantum rate and the luminous rate of the AlGaN-based ultraviolet LED epitaxial structure are improved.)

1. An aluminum gallium nitrogen based ultraviolet LED epitaxial structure, comprising: the light-emitting diode comprises a substrate, a buffer layer, a first aluminum gallium nitride layer, a light-emitting layer and a second aluminum gallium nitride layer which are sequentially stacked, wherein the first aluminum gallium nitride layer is used for providing electrons, the second aluminum gallium nitride layer is used for providing holes, and the light-emitting layer is used for radiation combined luminescence of the electrons and the holes;

the second aluminum gallium nitrogen layer comprises a plurality of second aluminum gallium nitrogen sublayers, the second aluminum gallium nitrogen sublayers are sequentially stacked and arranged, the aluminum components of the second aluminum gallium nitrogen sublayers are different, and the aluminum components of the second aluminum gallium nitrogen sublayers connected with the light-emitting layer are larger than those of the other second aluminum gallium nitrogen sublayers.

2. The AlGaN-based ultraviolet LED epitaxial structure of claim 1, wherein the aluminum composition of each of the second AlGaN sublayers decreases in sequence from being close to the light emitting layer to being far from the light emitting layer.

3. The AlGaN-based ultraviolet LED epitaxial structure of claim 2, wherein the aluminum composition of each of the second AlGaN sublayers decreases linearly from the near side to the far side of the light emitting layer.

4. The AlGaN-based ultraviolet LED epitaxial structure of claim 2, wherein the aluminum composition of the second AlGaN sublayer is 0-0.8.

5. The AlGaN-based ultraviolet LED epitaxial structure of claim 4, wherein the aluminum composition of the second AlGaN sublayer is 0.05-0.65.

6. The AlGaN-based ultraviolet LED epitaxial structure of claim 1, wherein the second AlGaN sublayers have equal thicknesses.

7. The AlGaN-based ultraviolet LED epitaxial structure of claim 6, wherein the thickness of the second AlGaN sublayer is 20-30 nm.

8. The AlGaN-based ultraviolet LED epitaxial structure of claim 1, wherein the dopant atoms of the second AlGaN layer comprise magnesium atoms.

9. The AlGaN-based ultraviolet LED epitaxial structure of claim 8, wherein the doping concentration of magnesium atoms in the second AlGaN layer is 1 x 10¹⁷cm^-3。

10. An ultraviolet LED lamp, comprising a lamp holder, a lamp cover and the aigan based ultraviolet LED epitaxial structure as claimed in any one of claims 1 to 9, wherein the aigan based ultraviolet LED epitaxial structure is disposed on the lamp holder, the lamp cover is connected to the lamp holder, and the aigan based ultraviolet LED epitaxial structure is covered.

Technical Field

The invention relates to the technical field of semiconductors, in particular to an aluminum gallium nitrogen based ultraviolet LED epitaxial structure and an ultraviolet LED lamp.

Background

With the continuous development of Light Emitting Diode (LED) technology, uv LEDs are more and more important in the commercial field, and have significant application value. In addition, compared with the traditional ultraviolet light source mercury lamp, the ultraviolet LED has the advantages of ultra-long service life, no heat radiation, high energy, uniform irradiation, high efficiency, small volume, no toxic substances and the like, so that the ultraviolet LED is most likely to replace the traditional ultraviolet light source. Therefore, ultraviolet LEDs are receiving increasing attention from researchers. The luminous power of the ultraviolet LED is related to the internal quantum rate of light emitted by an ultraviolet LED epitaxial wafer in the ultraviolet LED, and the currently prepared ultraviolet LED epitaxial wafer mainly adopts III-group nitride AlGaN (aluminum gallium nitrogen) materials.

However, strong spontaneous and piezoelectric polarization exists between the group III nitride materials, so that a strong polarization electric field is generated, and finally, electrons in the luminescent layer leak, and the radiation recombination efficiency of the electrons and the holes in the luminescent layer is reduced, so that the internal quantum rate of light emitted by the ultraviolet LED epitaxial wafer is low, and further, the luminous power of the ultraviolet LED epitaxial wafer is low.

Disclosure of Invention

Accordingly, there is a need for an aluminum gallium nitride based ultraviolet LED epitaxial structure and an ultraviolet LED lamp with a simple structure and improved internal quantum efficiency and luminous efficiency.

An aluminum gallium nitride based ultraviolet LED epitaxial structure, comprising: the light-emitting diode comprises a substrate, a buffer layer, a first aluminum gallium nitride layer, a light-emitting layer and a second aluminum gallium nitride layer which are sequentially stacked, wherein the first aluminum gallium nitride layer is used for providing electrons, the second aluminum gallium nitride layer is used for providing holes, and the light-emitting layer is used for radiation combined luminescence of the electrons and the holes; the second aluminum gallium nitrogen layer comprises a plurality of second aluminum gallium nitrogen sublayers, the second aluminum gallium nitrogen sublayers are sequentially stacked and arranged, the aluminum components of the second aluminum gallium nitrogen sublayers are different, and the aluminum components of the second aluminum gallium nitrogen sublayers connected with the light-emitting layer are larger than those of the other second aluminum gallium nitrogen sublayers.

In one embodiment, the aluminum composition of each second aluminum gallium nitride sublayer decreases sequentially from the position close to the light emitting layer to the position far away from the light emitting layer.

In one embodiment, the aluminum composition of each second aluminum gallium nitride sublayer decreases linearly from the position close to the light emitting layer to the position far away from the light emitting layer.

In one embodiment, the aluminum composition of the second aluminum gallium nitrogen sublayer is 0-0.8.

In one embodiment, the aluminum composition of the second aluminum gallium nitrogen sublayer is 0.05-0.65.

In one embodiment, the thicknesses of the second aluminum gallium nitride sublayers are equal.

In one embodiment, the thickness of the second aluminum gallium nitrogen sublayer is 20-30 nm.

In one embodiment, the dopant atoms of the second aluminum gallium nitrogen layer comprise magnesium atoms.

In one embodiment, the doping concentration of magnesium atoms in the second AlGaN layer is 1 × 10¹⁷cm^-3。

The utility model provides an ultraviolet LED lamp, includes lamp stand, lamp shade and above-mentioned arbitrary embodiment aluminium gallium nitrogen base ultraviolet LED epitaxial structure, aluminium gallium nitrogen base ultraviolet LED epitaxial structure set up in on the lamp stand, the lamp shade with the lamp stand is connected, and covers and establish aluminium gallium nitrogen base ultraviolet LED epitaxial structure.

According to the aluminum gallium nitrogen based ultraviolet LED epitaxial structure and the ultraviolet LED lamp, the aluminum component of the second aluminum gallium nitrogen sublayer close to the light emitting layer is largest, and the aluminum gallium nitrogen based ultraviolet LED epitaxial structure and the ultraviolet LED lamp are used for reducing the leakage of electrons from the light emitting layer; the aluminum component of the second aluminum gallium nitrogen sublayer far away from the light-emitting layer is minimum, and is used for providing holes for the light-emitting layer; the second AlGaN sublayer with different components weakens the built-in electric field of the second AlGaN layer, weakens the piezoelectric polarization effect between the second AlGaN layer and the luminous layer, improves the effective injection rate of holes, has the functions of blocking the leakage of electrons and increasing the injection rate of holes, improves the radiation recombination rate of electrons and holes, and improves the internal quantum rate and the luminous rate of the AlGaN-based ultraviolet LED epitaxial structure.

Drawings

Fig. 1 is a schematic structural diagram of an aluminum gallium nitride based ultraviolet LED epitaxial structure according to an embodiment.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention 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.

It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

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 invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The invention relates to an aluminum gallium nitrogen-based ultraviolet LED epitaxial structure. For example, the aluminum gallium nitride based ultraviolet LED epitaxial structure includes: the light-emitting diode comprises a substrate, a buffer layer, a first aluminum gallium nitride layer, a light-emitting layer and a second aluminum gallium nitride layer which are sequentially stacked, wherein the first aluminum gallium nitride layer is used for providing electrons, the second aluminum gallium nitride layer is used for providing holes, and the light-emitting layer is used for radiation combined luminescence of the electrons and the holes; the second aluminum gallium nitrogen layer comprises a plurality of second aluminum gallium nitrogen sublayers, the second aluminum gallium nitrogen sublayers are sequentially stacked and arranged, the aluminum components of the second aluminum gallium nitrogen sublayers are different, and the aluminum components of the second aluminum gallium nitrogen sublayers connected with the light-emitting layer are larger than those of the other second aluminum gallium nitrogen sublayers. The aluminum component of the second aluminum gallium nitrogen sublayer close to the light-emitting layer is largest and is used for reducing the leakage of electrons from the light-emitting layer; the aluminum component of the second aluminum gallium nitrogen sublayer far away from the light-emitting layer is minimum, and is used for providing holes for the light-emitting layer; the second AlGaN sublayer with different components weakens the built-in electric field of the second AlGaN layer, weakens the piezoelectric polarization effect between the second AlGaN layer and the luminous layer, improves the effective injection rate of holes, has the functions of blocking the leakage of electrons and increasing the injection rate of holes, improves the radiation recombination rate of electrons and holes, and improves the internal quantum rate and the luminous rate of the AlGaN-based ultraviolet LED epitaxial structure.

Please refer to fig. 1, which is a schematic structural diagram of an aluminum gallium nitride based ultraviolet LED epitaxial structure according to an embodiment of the present invention.

An aluminum gallium nitride based ultraviolet LED epitaxial structure 10, comprising: the light-emitting layer comprises a substrate 100, a buffer layer 200, a first aluminum gallium nitride layer 300, a light-emitting layer 400 and a second aluminum gallium nitride layer 500 which are sequentially stacked, wherein the first aluminum gallium nitride layer 300 is used for providing electrons, the second aluminum gallium nitride layer 500 is used for providing holes, and the light-emitting layer 400 is used for radiation recombination luminescence of the electrons and the holes; the second aluminum gallium nitride layer 500 includes a plurality of second aluminum gallium nitride sublayers 510, and is a plurality of the second aluminum gallium nitride sublayers 510 are stacked in sequence, and is a plurality of the second aluminum gallium nitride sublayers 510 have different aluminum components, and the aluminum component of the second aluminum gallium nitride sublayer connected to the light emitting layer 400 is greater than the aluminum components of the other second aluminum gallium nitride sublayers.

In this embodiment, the aluminum component of the second aluminum gallium nitride sublayer is the aluminum content in the material of the second aluminum gallium nitride sublayer. The second aluminum gallium nitride sublayer 510 close to the light emitting layer 400 has the largest aluminum component for reducing leakage of electrons from the light emitting layer 400; the second aluminum gallium nitride sublayer 510, which is remote from the light emitting layer 400, has the smallest aluminum composition for providing holes to the light emitting layer 400; the second aluminum gallium nitrogen sublayer 510 of different components has weakened the built-in electric field of second aluminum gallium nitrogen layer 500, make the piezoelectricity polarization effect between second aluminum gallium nitrogen layer 500 and luminescent layer 400 weaken, thereby improve the effective injection rate in hole, make second aluminum gallium nitrogen sublayer 510 have the function of blockking that electron reveals and increase hole injection rate concurrently, and then make the radiation recombination rate in electron and hole improve, the internal quantum rate and the luminous rate of aluminum gallium nitrogen based ultraviolet LED epitaxial structure have been improved.

In one embodiment, referring to fig. 1, the aluminum composition of each of the second aluminum gallium nitride sublayers 510 decreases sequentially from the position close to the light emitting layer 400 to the position far away from the light emitting layer 400. Since the second aluminum gallium nitride layer is composed of a plurality of second aluminum gallium nitride sublayers 510, and the aluminum composition of each second aluminum gallium nitride sublayer 510 is different, that is, the aluminum composition of the second aluminum gallium nitride sublayer 510 close to the light emitting layer 400 is the largest, and the aluminum composition of the second aluminum gallium nitride sublayer 510 farthest from the light emitting layer 400 is the smallest. In this embodiment, the second aluminum gallium nitride sublayer 510 connected to the light emitting layer 400 is referred to as a first layer, the second aluminum gallium nitride sublayer 510 farthest from the light emitting layer 400 is referred to as a second layer, the second aluminum gallium nitride sublayer 510 located between the first layer and the second layer is referred to as a third layer, the third layer includes at least one third sublayer, the aluminum component of the first layer is the largest, the aluminum component of the second layer is the smallest, and the aluminum component of the third sublayer is located between the aluminum component of the first layer and the aluminum component of the second layer, that is, the aluminum component of the third sublayer is smaller than the aluminum component of the first layer and larger than the aluminum component of the second layer. Since the aluminum composition of the first layer is the largest, electrons in the light emitting layer 400 are blocked by the first layer, thereby reducing the leakage of electrons in the light emitting layer 400 into the second aluminum gallium nitride layer 500 and playing a role in blocking the leakage of electrons; the second layer has a minimum aluminum composition, and is used for connection with an external electrode for providing a high concentration of holes, and the third layer has an aluminum composition smaller than that of the first layer for providing a high concentration of holes in cooperation with the second layer. Thus, the second AlGaN layer 500 is composed of the first layer, the second layer, and the third layer, that is, the second aluminum gallium nitride layer 500 is composed of the second aluminum gallium nitride sublayer 510 with different aluminum composition, that is, the second aluminum gallium nitride layer 500 is composed of the second aluminum gallium nitride sublayer 510 with successively decreasing aluminum composition, so that an electric field opposite to the built-in electric field is formed between two adjacent second aluminum gallium nitride sublayers 510 in the second aluminum gallium nitride layer 500, thereby weakening the built-in electric field of the second aluminum gallium nitride layer 500, thereby weakening the piezoelectric polarization effect between the second AlGaN layer 500 and the light-emitting layer 400, improving the effective injection rate of holes, the second aluminum gallium nitrogen sublayer 510 has the functions of blocking electron leakage and increasing hole injection rate, and improves the radiation recombination rate of electrons and holes, so that the internal quantum rate and the luminous rate of the aluminum gallium nitrogen-based ultraviolet LED epitaxial structure are improved.

In one embodiment, referring to fig. 1, the aluminum composition of each of the second aluminum gallium nitride sublayers 510 decreases linearly from the position close to the light emitting layer 400 to the position away from the light emitting layer 400. In this embodiment, the number of the second aluminum gallium nitride sublayer 510 is four, from being close to the light emitting layer 400 to being far away from the light emitting layer 400, the second aluminum gallium nitride layer 500 includes the first polarization layer, the second polarization layer, the third polarization layer and the fourth polarization layer which are stacked in sequence, the first polarization layer is connected with the face of the light emitting layer 400 deviating from the first aluminum gallium nitride layer 300, the second polarization layer deviates from the light emitting layer 400 and is connected, the third polarization layer deviates from the second polarization layer and is connected with the first polarization layer, and the fourth polarization layer deviates from the third polarization layer and is connected with the second polarization layer. The aluminum composition of the first polarization layer, the aluminum composition of the second polarization layer, the aluminum composition of the third polarization layer and the aluminum composition of the fourth polarization layer are sequentially and linearly reduced, that is, the aluminum composition of the first polarization layer, the aluminum composition of the second polarization layer, the aluminum composition of the third polarization layer and the aluminum composition of the fourth polarization layer are arranged in an arithmetic progression, that is, the absolute values of the differences between the aluminum compositions of the two adjacent second aluminum gallium nitride sublayers 510 are equal. Like this, it is a plurality of the aluminium component of second aluminium gallium nitrogen sublayer 510 is linear decline, makes adjacent two the electric field that forms between the second aluminium gallium nitrogen sublayer 510 is more even, thereby makes the weakening of the built-in electric field of second aluminium gallium nitrogen layer 500 is even, promptly the electric field intensity of the built-in electric field of second aluminium gallium nitrogen layer 500 evenly weakens in proper order, thereby makes under the condition that the built-in electric field of second aluminium gallium nitrogen layer 500 evenly weakens, improves the effective injection rate of hole for second aluminium gallium nitrogen sublayer 510 has the function of blockking that electron reveals and increase hole injection rate concurrently, has improved the radiation recombination rate of electron and hole, thereby has improved aluminium gallium nitrogen base ultraviolet LED epitaxial structure's internal quantum rate and luminous rate.

In one embodiment, referring to fig. 1, the aluminum composition of the second aluminum gallium nitride sublayer 510 is 0 to 0.8. In one embodiment, the aluminum composition of the second aluminum gallium nitride sublayer is 0-0.8 and is not 0. In this embodiment, the second aluminum gallium nitride layer 500 includes four second aluminum gallium nitride sublayers 510, and the aluminum composition of the four second aluminum gallium nitride sublayers 510 is between 0 and 0.8, wherein the aluminum composition of the second aluminum gallium nitride sublayer 510 close to the light emitting layer 400 is the largest, that is, the aluminum composition of the second aluminum gallium nitride sublayer 510 close to the light emitting layer 400 is smaller than and approaches to 0.8; the aluminum composition of the second aluminum gallium nitride sublayer 510 farthest from the light emitting layer 400 is the smallest, that is, the aluminum composition of the second aluminum gallium nitride sublayer 510 farthest from the light emitting layer 400 is greater than and close to 0; the aluminum component of the second aluminum gallium nitride sublayer 510 between the two second aluminum gallium nitride sublayers 510 is between 0 and 0.8. Thus, the aluminum composition of the four second aluminum gallium nitride sublayers 510 is different, and the aluminum composition of the second aluminum gallium nitride sublayer 510 close to the light emitting layer 400 is the largest and serves as an electron blocking layer for blocking electrons in the light emitting layer 400 from leaking into the second aluminum gallium nitride layer 500, and the aluminum composition of the other second aluminum gallium nitride sublayers 510 is smaller than that of the second aluminum gallium nitride sublayer 510 close to the light emitting layer 400, that is, the other second aluminum gallium nitride sublayers 510 provide holes, wherein the aluminum composition of the second aluminum gallium nitride sublayer 510 farthest from the light emitting layer 400 is the smallest and serves to provide high-concentration holes. The second aluminum gallium nitrogen sublayer 510 with different aluminum components weakens the built-in electric field of the second aluminum gallium nitrogen layer 500, so that the piezoelectric polarization effect between the second aluminum gallium nitrogen layer 500 and the luminescent layer 400 is weakened, the effective injection rate of holes is improved, the second aluminum gallium nitrogen sublayer 510 has the functions of blocking the leakage of electrons and increasing the injection rate of holes, the radiation recombination rate of electrons and holes is improved, and the internal quantum rate and the luminous rate of the aluminum gallium nitrogen-based ultraviolet LED epitaxial structure are improved. In other embodiments, the aluminum composition of the second aluminum gallium nitride sublayer 510 is 0.05 to 0.65, the second aluminum gallium nitride layer 500 includes four second aluminum gallium nitride sublayers 510 stacked in sequence, the four second aluminum gallium nitride sublayers 510 are a first polarization layer, a second polarization layer, a third polarization layer and a fourth polarization layer in sequence, the aluminum composition of the first polarization layer is 0.65, the aluminum composition of the second polarization layer is 0.45, the aluminum composition of the third polarization layer is 0.25, and the aluminum composition of the fourth polarization layer is 0.05. The equal difference of the aluminum components of the four second aluminum gallium nitrogen sublayers 510 is reduced, so that the electric field formed between the two second aluminum gallium nitrogen sublayers 510 is more uniform, thereby the built-in electric field of the second aluminum gallium nitrogen sublayer 500 is uniformly weakened, namely, the electric field strength of the built-in electric field of the second aluminum gallium nitrogen sublayer 500 is uniformly weakened in sequence, so that the effective injection rate of holes is improved under the condition that the built-in electric field of the second aluminum gallium nitrogen sublayer 500 is uniformly weakened, the second aluminum gallium nitrogen sublayer 510 has the functions of blocking the leakage of electrons and increasing the injection rate of holes, the radiation recombination rate of electrons and holes is improved, and the internal quantum rate and the luminous rate of the aluminum gallium nitrogen-based ultraviolet LED epitaxial structure are improved.

In one embodiment, referring to fig. 1, the second aluminum gallium nitride sublayers 510 have equal thickness. Under the condition of being electrified, the epitaxial structure of the AlGaN-based ultraviolet LED forms an electric field between the surfaces of two adjacent second AlGaN sublayers 510, the field intensity direction of the electric field is opposite to the field intensity direction of a built-in electric field in the second AlGaN sublayers 510, and the function of the epitaxial structure is to weaken the built-in electric field of the second AlGaN layer 500, so that holes are easier to inject into the light-emitting layer 400 from the second AlGaN layer 500, namely, the effective injection rate of the holes is improved. The thicknesses of the second aluminum gallium nitrogen sublayers 510 are uniform and equal, and high-concentration holes generated by the second aluminum gallium nitrogen layer 500 sequentially pass through the second aluminum gallium nitrogen sublayers 510 with the same thickness, so that the strokes of the holes passing through each layer of the second aluminum gallium nitrogen sublayers 510 are the same, the holes can more easily pass through the second aluminum gallium nitrogen layer 500, the effective injection rate of the holes is improved, the radiation recombination rate of electrons and the holes is improved, and the internal quantum rate and the luminous rate of the aluminum gallium nitrogen-based ultraviolet LED epitaxial structure are improved.

In one embodiment, referring to fig. 1, the thickness of the second aluminum gallium nitride sublayer 510 is 20 to 30 nm. In this embodiment, the second aluminum gallium nitride layer 500 includes four second aluminum gallium nitride sublayers 510, and the second aluminum gallium nitride sublayers 510 are made of aluminum gallium nitride, but the aluminum composition of the second aluminum gallium nitride sublayers 510 of each layer is different. The four layers of the second aluminum gallium nitride sublayers 510 are sequentially stacked, the thickness of each layer of the second aluminum gallium nitride sublayer 510 is the same, the thickness of the four layers of the second aluminum gallium nitride sublayers 510 is the same, and the second aluminum gallium nitride sublayers 510 with different aluminum components jointly form the second aluminum gallium nitride layer 500. Under the condition that the aluminum gallium nitrogen-based ultraviolet LED epitaxial structure is electrified, the second aluminum gallium nitrogen layer 500 is used for generating holes, wherein the aluminum composition of the aluminum gallium nitrogen sublayer far away from the light emitting layer 400 is smaller than that of the aluminum gallium nitrogen sublayer close to the light emitting layer 400, the aluminum gallium nitrogen sublayer far away from the light emitting layer 400 is used for generating high-concentration holes, and the four second aluminum gallium nitrogen sublayers 510 with the same thickness enable the hole effective injection rate of each aluminum gallium nitrogen sublayer to be increased, so that the hole effective injection rate of the aluminum gallium nitrogen layer is increased, the radiation recombination rate of electrons and holes is improved, and further the internal quantum rate and the luminous rate of the aluminum gallium nitrogen-based ultraviolet LED epitaxial structure are improved. In other embodiments, the thicknesses of the four second aluminum gallium nitride sublayers 510 are equal, and the thickness of each second aluminum gallium nitride sublayer 510 is 25nm, so that the thickness of the second aluminum gallium nitride layer 500 is reduced under the condition of ensuring the effective hole injection rate of the second aluminum gallium nitride layer 500, thereby reducing the overall thickness of the aluminum gallium nitride-based ultraviolet LED epitaxial structure.

In one embodiment, referring to fig. 1, the dopant atoms of the second aluminum gallium nitride layer 500 include magnesium atoms. In this embodiment, the material of second aluminium gallium nitrogen layer 500 is for being P type aluminium gallium nitrogen, just second aluminium gallium nitrogen layer 500 forms through the technology preparation of polarization doping, second aluminium gallium nitrogen layer 500 includes the four layers second aluminium gallium nitrogen sublayer 510, promptly second aluminium gallium nitrogen layer 500 includes the first polarization that once stacks up the setting and dopes aluminium gallium nitrogen layer, second polarization doping aluminium gallium nitrogen layer, third polarization doping aluminium gallium nitrogen layer and fourth polarization doping aluminium gallium nitrogen layer, first polarization doping aluminium gallium nitrogen layer with luminescent layer 400 is connected, first polarization doping aluminium gallium nitrogen layer second polarization doping aluminium gallium nitrogen layer third polarization doping aluminium gallium nitrogen layer and the aluminium component of fourth polarization doping aluminium gallium nitrogen layer reduces linearly in proper order. Since each layer of the second aluminum gallium nitride layer 500 is made of the same material, i.e. the first polarization doped aluminum gallium nitride layer, the second polarization doped aluminum gallium nitride layer, the third polarization doped aluminum gallium nitride layer and the fourth polarization doped aluminum gallium nitride layer are made of P-type aluminum gallium nitride, the second aluminum gallium nitride layer 500 is doped more easily, wherein, the atoms doped in the second AlGaN layer 500 are magnesium atoms, and the activity of the magnesium atoms is stronger than that of the aluminum atoms, so that holes generated by the magnesium atoms in the AlGaN layer mixture are increased, thereby increasing the hole concentration provided by the second AlGaN layer 500, facilitating the second AlGaN layer 500 to provide a high concentration of holes for the light-emitting layer 400, further, the effective hole injection rate of the second aluminum gallium nitride layer 500 is improved, the radiative recombination rate of electrons and holes is improved, and the internal quantum rate and the luminous efficiency of the aluminum gallium nitride-based ultraviolet LED epitaxial structure are further improved. In other embodiments, the dopant atoms of the second aluminum gallium nitride layer 500 may also include other atoms that may generate a large number of holes, for example, the dopant atoms of the second aluminum gallium nitride layer 500 may include gold atoms; as another example, the dopant atoms of the second aluminum gallium nitride layer 500 include silver atoms. The doping atoms are used for increasing the number of holes of the second aluminum gallium nitride layer 500, so that the effective hole injection rate of the second aluminum gallium nitride layer 500 is increased, the radiation recombination rate of electrons and holes is improved conveniently, and the internal quantum rate and the luminous rate of the aluminum gallium nitride-based ultraviolet LED epitaxial structure are further improved.

In one embodiment, the second aluminum gallium nitride layer 500 comprises four P-type aluminum gallium nitride layers with sequentially linearly decreasing aluminum components, and the doping atoms of the second aluminum gallium nitride layer 500 are magnesium atoms with a doping concentration of 1 × 10¹⁷cm^-3The substrate 100 comprises a C-plane sapphire substrate 100, the buffer layer 200 comprises an undoped aluminum gallium nitride layer, the thickness of the buffer layer 200 is 1-2 μm, the first aluminum gallium nitride layer 300 is an N-type aluminum gallium nitride layer, the thickness of the first aluminum gallium nitride layer 300 is 1-3 μm, the light emitting layer 400 comprises a plurality of quantum barrier layers and a plurality of quantum well layers, the quantum barrier layers and the quantum well layers are sequentially stacked, the thickness of the quantum barrier layers is 8-20 μm, and the thickness of the quantum well layers is 2-7 μm. Thus, the aluminum component of the second aluminum gallium nitrogen sublayer close to the light-emitting layer is the largest, and is used for reducing the leakage of electrons from the light-emitting layer; the aluminum component of the second aluminum gallium nitrogen sublayer far away from the light-emitting layer is minimum, and is used for providing holes for the light-emitting layer; the second AlGaN sublayer with different components weakens the built-in electric field of the second AlGaN layer, weakens the piezoelectric polarization effect between the second AlGaN layer and the luminous layer, improves the effective injection rate of holes, has the functions of blocking the leakage of electrons and increasing the injection rate of holes, improves the radiation recombination rate of electrons and holes, and improves the internal quantum rate and the luminous rate of the AlGaN-based ultraviolet LED epitaxial structure.

In one embodiment, the second aluminum gallium nitride layer 500 includes four second aluminum gallium nitride sublayers 510 with equal thickness, and the thickness of each second aluminum gallium nitride sublayer 510 is 20 to 30nm, that is, the thickness of the second aluminum gallium nitride layer 500 is 80 to 120 nm. Wherein, the four layers second aluminium gallium nitrogen sublayer 510 is respectively for the first polarization doping aluminium gallium nitrogen layer, the second polarization doping aluminium gallium nitrogen layer, the third polarization doping aluminium gallium nitrogen layer and the fourth polarization doping aluminium gallium nitrogen layer that stack gradually the setting, first polarization doping aluminium gallium nitrogen layer with luminescent layer 400 deviates from first aluminium gallium nitrogen layer 300 is connected, the aluminium component on first polarization doping aluminium gallium nitrogen layer is 0.65, the aluminium component on second polarization doping aluminium gallium nitrogen layer is 0.45, the aluminium component on third polarization doping aluminium gallium nitrogen layer is 0.25, the aluminium component on fourth polarization doping aluminium gallium nitrogen layer is 0.05.

In the aluminum gallium nitrogen based ultraviolet LED epitaxial structure, the aluminum component of the second aluminum gallium nitrogen sublayer close to the light emitting layer is largest, so that the leakage of electrons from the light emitting layer is reduced; the aluminum component of the second aluminum gallium nitrogen sublayer far away from the light-emitting layer is minimum, and is used for providing holes for the light-emitting layer; the second AlGaN sublayer with different components weakens the built-in electric field of the second AlGaN layer, weakens the piezoelectric polarization effect between the second AlGaN layer and the luminous layer, improves the effective injection rate of holes, has the functions of blocking the leakage of electrons and increasing the injection rate of holes, improves the radiation recombination rate of electrons and holes, and improves the internal quantum rate and the luminous rate of the AlGaN-based ultraviolet LED epitaxial structure.

In one of them embodiment, this application still provides an ultraviolet LED lamp, including lamp stand, lamp shade and above-mentioned arbitrary embodiment aluminium gallium nitrogen base ultraviolet LED epitaxial structure, aluminium gallium nitrogen base ultraviolet LED epitaxial structure set up in on the lamp stand, the lamp shade with the lamp stand is connected, and covers and establish aluminium gallium nitrogen base ultraviolet LED epitaxial structure.

In the ultraviolet LED lamp, the aluminum component of the second aluminum gallium nitride sublayer close to the light-emitting layer is largest, so that leakage of electrons from the light-emitting layer is reduced; the aluminum component of the second aluminum gallium nitrogen sublayer far away from the light-emitting layer is minimum, and is used for providing holes for the light-emitting layer; the second aluminium gallium nitrogen sublayer of different components has weakened the built-in electric field on second aluminium gallium nitrogen layer, make the piezoelectricity polarization effect between second aluminium gallium nitrogen layer and the luminescent layer weaken, thereby improve the effective injection rate in hole, make second aluminium gallium nitrogen sublayer have concurrently and block the function that electron was revealed and increase hole injection rate, and then make the radiation recombination rate in electron and hole improve, the internal quantum rate and the luminous rate of aluminium gallium nitrogen base ultraviolet LED epitaxial structure have been improved, improve the luminous efficacy of ultraviolet LED lamp promptly.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.