An epitaxial structure of an AlInGaN-based optoelectronic device

Abstract

The present invention discloses an epitaxial structure of an AlInGaN-based optoelectronic device, comprising a substrate, a buffer layer, an n-type AlInGaN layer, an AlInGaN superlattice layer with a V-pit, an n-region AlInGaN electron blocking layer with a V-pit, an AlInGaN-based multi-quantum well layer with a V-pit, a p-region AlInGaN electron blocking layer with a V-pit, and a p-type AlInGaN layer. The epitaxial structure is characterized in that: the V-pit sidewall thickness of the n-region AlInGaN electron blocking layer with a V-pit is greater than the platform thickness; an n-type AlInGaN highly doped layer with a V-pit is contained between the n-region AlInGaN electron blocking layer with a V-pit and the AlInGaN-based multi-quantum well layer with a V-pit; the V-pit sidewall thickness of the p-region AlInGaN electron blocking layer with a V-pit is less than the platform thickness; and a p-type AlInGaN highly doped layer merging the V-pit is contained between the p-region AlInGaN electron blocking layer with a V-pit and the p-type AlInGaN layer. The present invention has the function of improving the efficiency of hole injection and collection, regulating the injection and collection pathways of electrons and holes, and can be applied to Micro-LEDs, photodetectors, and solar cells.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor optoelectronics and display technology, and in particular to an epitaxial structure of an AlInGaN-based optoelectronic device. Background Art

[0002] With the continuous advancement of information technology, people's lifestyles have undergone profound changes. Group III nitride semiconductors, represented by GaN-based materials, have a range of characteristics, including wide bandgap, direct bandgap, high electron mobility, high breakdown electric field, high electron saturation drift velocity, high thermal conductivity, low dielectric constant, high temperature resistance, strong radiation resistance, and high chemical stability. By adjusting the composition of their ternary or quaternary compounds, they can be widely used in photodetectors, solar cells, LED lighting, and displays.

[0003] When GaN-based LED chips are reduced in size to tens or even just a few microns, they are called micro-LEDs. Micro-LEDs hold significant value in high-resolution displays, high-speed visible light communications, micro-projectors, and wearable electronics. However, as device size decreases, leakage current easily develops along the sides of the micro-LEDs, and dangling bonds along the sides can lead to non-radiative recombination, dramatically degrading device performance. Photodetectors and solar cells both convert light signals into electrical signals. Photodetectors require reverse bias, but they essentially separate photogenerated electron-hole pairs using an electric field, allowing electrons to be collected in the n-region and holes in the p-region. InGaN-based photodetectors typically employ PIN or MSM structures, while solar cells primarily employ heterojunction structures. Photogenerated carriers consist of both electrons and holes, with the mobility of holes being lower than that of electrons. The collection efficiency of these carriers is a key factor limiting the photocurrent in both photodetectors and solar cells, and this efficiency is closely related to the electric field within the device. For InGaN and GaN material systems, there is a strong spontaneous polarization effect in the material. At the same time, due to the biaxial compressive stress of the InGaN layer, a piezoelectric polarization electric field is generated, which will have a significant impact on the transport of photogenerated carriers. At the same time, the interface barrier of the well barrier of InGaN photodetectors and solar cells with high In content will have an adverse effect on the transport of photogenerated carriers. The Chinese invention patent with authorization publication number CN106298990B, "A non-polar solar cell using spontaneous polarization electric field", has a spontaneous polarization electric field in a single direction parallel to the epitaxial layer within its non-polar epitaxial layer, which is beneficial to improving the lateral separation and transport efficiency of photogenerated carriers in the solar cell. The Chinese invention patent with authorization publication number CN107240615B, "A UV detector with a non-polar absorption layer", uses a non-polar absorption layer to avoid the compensation effect of the polarization electric field within the absorption layer on the built-in electric field of the pn junction, thereby improving the photogenerated current of the UV detector. In the above-mentioned patents, the quantum wells in the non-polar or semi-polar planes have less polarization charge, a smaller polarization field, and a weakened energy band tilt of the quantum wells. Therefore, to achieve the same wavelength, more In components are required. In addition, the incorporation efficiency of In components on the non-polar and semi-polar planes is low, requiring a lower growth temperature, which will deteriorate the crystal quality of the quantum wells. The Chinese invention patent "A mixed polarity InGaN solar cell structure" with authorization announcement number CN108269866B has the same direction of the total polarization electric field in the light absorption layer i as the built-in electric field, so that the polarization effect does not hinder the separation and transport of photogenerated carriers, thereby obtaining a high-efficiency InGaN solar cell. The above-mentioned patents only have an improvement effect on InGaN solar cells and photodetectors with low In components, and non-polar and semi-polar materials are difficult to grow and have poor crystal quality.The InGaN solar cells with an In content higher than 25% reported in the literature have an abnormal "staircase-like" current-voltage curve, which makes it difficult to collect photogenerated carriers in the device, but no solution has been proposed (see the literature: Cai XM, Zheng ZW, Long H, et al. Abnormal staircase-like IV curve in InGaN quantumwell solar cells [J]. Applied Physics Letters, 2018, 112 (16): 161102.). In the Chinese invention patent with the authorization announcement number CN103400872B, "Structure of surface electric field enhanced PIN photodetector and its preparation method", a p-type heavily doped region is set in the area near the p-electrode, which introduces a horizontal electric field and strengthens the vertical electric field, thereby improving the collection efficiency of photogenerated holes and the quantum efficiency of the device. However, the horizontal electric field introduced by this method only exists in the area near the p-electrode, has a limited impact range, and the manufacturing process is complicated. This method is not applicable to material systems with high interface barriers. Summary of the Invention

[0004] The purpose of the present invention is to provide an epitaxial structure of an AlInGaN-based optoelectronic device. This structure uses a highly doped layer to obtain a strong built-in electric field with a horizontal component on the sidewall of the V-pit to improve the efficiency of hole injection and collection. At the same time, an electron blocking layer is used to regulate the transport pathways of electrons and holes, so that electrons are injected and collected from the platform and holes are injected and collected from the sidewall of the V-pit, thereby reducing the dark current and size effect of the device. The structure can be applied to Micro-LEDs, photodetectors, and solar cells.

[0005] The object of the present invention is achieved like this:

[0006] An epitaxial structure of an AlInGaN-based optoelectronic device comprises a substrate, a buffer layer, an n-type AlInGaN layer, an AlInGaN superlattice layer having a V-pit, an n-region AlInGaN electron blocking layer having a V-pit, an AlInGaN-based multi-quantum well layer having a V-pit, a p-region AlInGaN electron blocking layer having a V-pit, and a p-type AlInGaN layer. The epitaxial structure is characterized in that: the V-pit sidewall thickness of the n-region AlInGaN electron blocking layer having a V-pit is greater than the platform thickness; an n-type AlInGaN highly doped layer having a V-pit is contained between the n-region AlInGaN electron blocking layer having a V-pit and the AlInGaN-based multi-quantum well layer having a V-pit; the V-pit sidewall thickness of the p-region AlInGaN electron blocking layer having a V-pit is less than the platform thickness; and a p-type AlInGaN highly doped layer merging the V-pit is contained between the p-region AlInGaN electron blocking layer having a V-pit and the p-type AlInGaN layer.

[0007] The Si doping concentration of the n-type AlInGaN high-doping layer with V pit is 1×10 19 ~5×10 20 cm -3 .

[0008] The Mg doping concentration of the p-type AlInGaN high-doped layer with the merged V pit is 3×10 19 ~1×10 21 cm -3 .

[0009] The bandgap width of the n-region AlInGaN electron blocking layer with the V-pit is greater than the bandgap widths of all quantum barriers in the AlInGaN-based multi-quantum well layer with the V-pit.

[0010] The bandgap width of the p-region AlInGaN electron blocking layer with the V-pit is greater than the bandgap widths of all quantum barriers in the AlInGaN-based multi-quantum well layer with the V-pit.

[0011] The platform is a growth plane and a polar surface, namely the (0001) crystal plane family. The projection of the V-pit on the platform is a regular hexagon. The sidewall of the V-pit is a semi-polar surface, and the (1011) crystal plane family is the best.

[0012] The platform thickness from the lower surface of the first quantum well to the upper surface of the last quantum well of the AlInGaN-based multi-quantum well layer with V-pits is d1, and the distance between the opposite sides of the regular hexagonal projection of the V-pit on the upper surface of the last quantum well is d2. The relationship between the two satisfies d2>d1×2tan28°, and the units of d1 and d2 are nm.

[0013] The ratio of the sum of the areas of all regular hexagonal projections of the V-pit on the upper surface of the final quantum well to the area of the upper surface of the final quantum well is δ, and the value of δ ranges from 15% to 50%.

[0014] The density of the V pits on the surface of the last quantum well is ρ, that is, the number of V pits per unit area, and the ρ value range is 1×10 8 cm -2 ~1×10 10 cm -2 .

[0015] The substrate is one of Al2O3, SiC, GaN or Si.

[0016] The present invention utilizes a highly doped layer to create a strong built-in electric field at the horizontal component of the V-pit sidewalls, thereby improving the efficiency of hole injection and collection. Simultaneously, an electron blocking layer is used to regulate the transport pathways of electrons and holes, allowing electrons to be injected and collected from the terraces and holes to be injected and collected from the V-pit sidewalls, thereby reducing the device's dark current and size effect. Therefore, the present invention is characterized by:

[0017] 1. The n-type AlInGaN highly doped layer with V-pits and the p-type AlInGaN highly doped layer with merged V-pits are set up, which can effectively enhance the built-in electric field strength of the V-pit sidewalls, thereby increasing the electric field strength of the horizontal component of the built-in electric field on the V-pit sidewalls and improving the efficiency of hole injection and collection;

[0018] 2. An n-region AlInGaN electron blocking layer with a V-pit is provided. The sidewall thickness of the V-pit of the n-region AlInGaN electron blocking layer is greater than the thickness of the platform. This can control the electrons to be transported preferentially from the platform area. The thicker the V-pit sidewall is than the platform, the more significant the control effect is. This can prevent the leakage of electrons and holes from the V-pit and reduce the dark current of the device.

[0019] 3. A p-region AlInGaN electron blocking layer with a V-pit is set up. The thickness of the V-pit sidewall of the p-region AlInGaN electron blocking layer is smaller than the thickness of the platform. The thickness of the V-pit sidewall of the AlInGaN-based multi-quantum well layer is relatively thin and is a semi-polar surface with weak polarization. The holes can be controlled to be transported preferentially from the V-pit sidewall. The thinner the V-pit sidewall is than the platform, the more significant the control effect is, which can increase the local carrier concentration and reduce the size effect of the device.

[0020] The present invention can be applied to Micro-LEDs, photodetectors, and solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1The carrier injection and recombination pathways of the present invention when it is in a positive bias state; in the figure: 101 is a substrate, 201 is a buffer layer, 301 is an n-type AlInGaN layer, 401 is an AlInGaN superlattice layer with a V-pit, 501 is an n-region AlInGaN electron blocking layer with a V-pit, 601 is an n-type AlInGaN highly doped layer with a V-pit, 701 is an AlInGaN-based multi-quantum well layer with a V-pit, 801 is a p-region AlInGaN electron blocking layer with a V-pit, 901 is a p-type AlInGaN with a merged V-pit N is a highly doped layer, and 1001 is a p-type AlInGaN layer; in the figure, → represents the transport direction of electrons and holes, ● represents electrons, and ○ represents holes; in the figure: process ① represents the injection of holes from the sidewall of the V-pit of the p-region AlInGaN electron blocking layer 801 into the AlInGaN-based multi-quantum well layer 701, process ② represents the injection of electrons from the terrace of the n-region AlInGaN electron blocking layer 501 into the AlInGaN-based multi-quantum well layer 701, and process ③ represents the radiative recombination of electrons and holes in the AlInGaN-based multi-quantum well layer 701;

[0022] Figure 2 This is a separation and collection path for photogenerated carriers in the present invention when under zero bias or reverse bias; in the figure: 101 is a substrate, 201 is a buffer layer, 301 is an n-type AlInGaN layer, 401 is an AlInGaN superlattice layer with a V-pit, 501 is an n-region AlInGaN electron blocking layer with a V-pit, 601 is an n-type AlInGaN highly doped layer with a V-pit, 701 is an AlInGaN-based multiple quantum well layer with a V-pit, 801 is a p-region AlInGaN electron blocking layer with a V-pit, 901 is a p-type AlInGaN highly doped layer merging V-pits, and 1001 is a p-type AlInGaN layer; in the figure, → represents the transport direction of photogenerated electrons and photogenerated holes, ● in the figure represents photogenerated electrons, ○ in the figure represents photogenerated holes, and Indicates the direction of the built-in electric field of the horizontal component of the V-pit sidewall; in the figure: process ① represents the lateral migration of photogenerated holes toward the V-pit, process ② represents the lateral migration of photogenerated electrons in the opposite direction to the V-pit, process ③ represents the photogenerated holes that migrated laterally toward the V-pit are collected from the V-pit sidewall of the AlInGaN-based multi-quantum well layer 701 and the p-region AlInGaN electron blocking layer 801 to the p-pole, and process ④ represents the photogenerated electrons that migrated laterally in the opposite direction to the V-pit are collected from the platform of the AlInGaN-based multi-quantum well layer 701 and the n-region AlInGaN electron blocking layer 501 to the n-pole;

[0023] Figure 3 For the side Schematic diagram of the V-pit structure on the surface;

[0024] Figure 4Schematic diagram of the epitaxial structure in Example 1 of the present invention; in the figure: 101 is a substrate, 201 is a buffer layer, 301 is an n-type AlInGaN layer, 401 is an AlInGaN superlattice layer with a V-pit, 501 is an n-region AlInGaN electron blocking layer with a V-pit, 601 is an n-type AlInGaN highly doped layer with a V-pit, 701 is an AlInGaN-based multi-quantum well layer with a V-pit, 701a is a first quantum well, 701b is a first quantum barrier, 701c is a second quantum well, 701d is a second quantum barrier, 701e is a third quantum well, 701f is a third quantum barrier, 701g is a fourth quantum well, 701h is a fourth quantum barrier, 70 1i is the fifth quantum well, 701j is the fifth quantum barrier, 701k is the sixth quantum well, 701l is the sixth quantum barrier, 701m is the seventh quantum well, 701n is the seventh quantum barrier, 701o is the eighth quantum well (last quantum well), 701p is the eighth quantum barrier (last quantum barrier), 801 is the p-region AlInGaN electron blocking layer with V-pit, 901 is the p-type AlInGaN high doping layer merged with the V-pit, and 1001 is the p-type AlInGaN layer; in the figure: d1 is the platform thickness from the lower surface of the first quantum well 701a to the upper surface of the last quantum well 701o, and d2 in the figure is the distance between the opposite sides of the regular hexagonal projection of the V-pit on the upper surface of the last quantum well 701o. DETAILED DESCRIPTION

[0025] In order to facilitate those skilled in the art to understand and implement the present invention, the present invention is further described in detail below with reference to the accompanying drawings.

[0026] like Figure 1As shown, when the structure of the present invention is in forward bias, the n-type AlInGaN highly doped layer 601 and the p-type AlInGaN highly doped layer 901 can enhance the built-in electric field of the horizontal component of the V-pit sidewall, thereby improving the hole injection efficiency; the V-pit sidewall thickness of the p-region AlInGaN electron blocking layer 801 is smaller than the platform thickness, and the V-pit sidewall thickness of the AlInGaN-based multi-quantum well layer 701 is relatively thin and is a semi-polar plane with weak polarization. Most holes are injected from the p-region AlInGaN electron barrier layer 801 as in process ①. The V-pit sidewalls of the electron-blocking layer 801 are injected into the AlInGaN-based multi-quantum well layer 701. The V-pit sidewalls of the n-region AlInGaN electron-blocking layer 501 are thicker than the terrace thickness, allowing most electrons to be injected from the terrace of the n-region AlInGaN electron-blocking layer 501 into the AlInGaN-based multi-quantum well layer 701 as in process ②. Holes injected from the V-pit sidewalls recombine with electrons in the region near the V-pit as in process ③, resulting in rapid consumption. However, the number of holes in areas farther from the V-pit drops sharply, weakening the luminescence. This results in the luminescence region being divided into two zones: a strong luminescence zone near the V-pit and a weak luminescence zone farther from the V-pit. The region near the V-pit can be compared to a quantum dot, where holes are localized to emit light, significantly reducing the volume of the effective recombination zone. LED chips fabricated with this structure can increase the local carrier concentration while maintaining a constant current density, reducing the chip's size effect and finding application in the Micro-LED field.

[0027] like Figure 2 As shown, when the structure of the present invention is in zero bias or reverse bias, the n-type AlInGaN highly doped layer 601 and the p-type AlInGaN highly doped layer 901 can enhance the built-in electric field of the horizontal component of the V-pit sidewall, so that the photogenerated holes and photogenerated electrons in the AlInGaN-based multi-quantum well layer 701 are separated in the horizontal direction. The holes migrate toward the V-pit as in process ①, and the electrons migrate in the opposite direction as in process ②. The holes that migrate toward the V-pit are separated from the AlInGaN-based multi-quantum well layer 701 and the p-region as in process ③. The V-pit sidewalls of the AlInGaN electron blocking layer 801 are collected at the p-pole, and electrons migrating in the opposite direction are collected at the n-pole from the AlInGaN-based multi-quantum well layer 701 and the platform of the n-region AlInGaN electron blocking layer 501 as in process ④, which can effectively improve the separation and collection of photogenerated carriers; at the same time, the V-pit sidewalls of the n-region AlInGaN electron blocking layer 501 are thicker than the platform, which can prevent electrons and holes from leaking through the V-pit, reducing the dark current of the device, and can be applied to the fields of photodetectors and solar cells.

[0028] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0029] Example 1:

[0030] like Figure 4The figure shows an epitaxial structure of an AlInGaN-based optoelectronic device, including a substrate 101, a buffer layer 201, an n-type AlInGaN layer 301, an AlInGaN superlattice layer 401 with V-pits, an n-region AlInGaN electron blocking layer 501 with V-pits, an AlInGaN-based multi-quantum well layer 701 with V-pits, a p-region AlInGaN electron blocking layer 801 with V-pits, and a p-type AlInGaN layer 1001. Among them, the V-pit sidewall thickness of the n-region AlInGaN electron blocking layer 501 with a V-pit is greater than the platform thickness, and the ratio of the V-pit sidewall thickness of the n-region AlInGaN electron blocking layer 501 with a V-pit to the platform thickness is 3; the n-type AlInGaN highly doped layer 601 with a V-pit is contained between the n-region AlInGaN electron blocking layer 501 with a V-pit and the AlInGaN-based multi-quantum well layer 701 with a V-pit; the V-pit sidewall thickness of the p-region AlInGaN electron blocking layer 801 with a V-pit is less than the platform thickness, and the ratio of the V-pit sidewall thickness of the p-region AlInGaN electron blocking layer 801 with a V-pit to the platform thickness is 1 / 3; the p-type AlInGaN highly doped layer 901 with a merged V-pit is contained between the p-region AlInGaN electron blocking layer 801 with a V-pit and the p-type AlInGaN layer 1001.

[0031] The bandgap widths of the n-region AlInGaN electron blocking layer 501 with V-pits and the p-region AlInGaN electron blocking layer 801 with V-pits are both larger than the bandgap widths of all quantum barriers in the AlInGaN-based multi-quantum well layer 701 with V-pits.

[0032] The Si doping concentration of the n-type AlInGaN high-doped layer 601 with a V-pit is 1×10 19 ~5×10 20 cm -3 .

[0033] The Mg doping concentration of the p-type AlInGaN high-doped layer 901 with the V-pit merged is 3×10 19 ~1×10 21 cm -3 .

[0034] The platform is a growth plane and a polar plane, namely the (0001) crystal plane family. The projection of the V-pit on the platform is a regular hexagon. The sidewall of the V-pit is a semi-polar plane, and the (1011) crystal plane family is the best.

[0035] The AlInGaN-based multi-quantum well layer 701 with V-pits has 8 well-barrier periods, of which 701a is the first quantum well, 701b is the first quantum barrier, 701c is the second quantum well, 701d is the second quantum barrier, 701e is the third quantum well, 701f is the third quantum barrier, 701g is the fourth quantum well, 701h is the fourth quantum barrier, 701i is the fifth quantum well, 701j is the fifth quantum barrier, 701k is the sixth quantum well, 701l is the sixth quantum barrier, 701m is the seventh quantum well, 701n is the seventh quantum barrier, 701o is the eighth quantum well (last quantum well), and 701p is the eighth quantum barrier (last quantum barrier).

[0036] The platform thickness from the lower surface of the first quantum well 701a of the AlInGaN-based multi-quantum well layer 701 with V-pit to the upper surface of the last quantum well 701o is d1, d1 = 111nm, and the distance between the opposite sides of the regular hexagonal projection of the V-pit on the upper surface of the last quantum well 701o is d2, d2 = 120nm.

[0037] The ratio of the sum of the areas of all regular hexagonal projections of the V-pit on the upper surface of the last quantum well 701o to the area of the upper surface of the last quantum well 701o is δ, and the value of δ ranges from 15% to 50%.

[0038] The density of V pits on the surface of the last quantum well 701o is ρ, that is, the number of V pits per unit area, and the ρ value range is 1×10 8 cm -2 ~1×10 10 cm -2 .

[0039] The substrate 101 is one of Al 2 O 3 , SiC, GaN or Si.

[0040] In the above embodiment:

[0041] The substrate 101 is a silicon substrate, the buffer layer 201 is AlN, and the n-type AlInGaN layer 301 is doped with Si at a concentration of 5×10 18 cm -3 The GaN, AlInGaN superlattice layer 401 is 32 periods of In 0.08 Ga 0.92 N / GaN periodic structure, the n-region AlInGaN electron blocking layer 501 is doped with Si at a concentration of 5×10 18 cm -3 Al 0.2 Ga 0.8 N, n-type AlInGaN high doping layer 601 is doped with Si at a concentration of 3×10 19 cm -3 In 0.1 Ga0.9 N, AlInGaN-based multi-quantum well layer 701 is 8 periods of In 0.3 Ga 0.7 N / GaN periodic structure, the p-region AlInGaN electron blocking layer 801 is doped with Mg at a concentration of 5×10 19 cm -3 Al 0.2 Ga 0.8 N, the p-type AlInGaN high-doped layer 901 with the merged V pit has a Mg doping concentration of 1×10 20 cm -3 In 0.1 Ga 0.9 N, p-type AlInGaN layer 1001 is doped with Mg at a concentration of 5×10 19 cm -3 GaN.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An epitaxial structure of an AlInGaN-based optoelectronic device, comprising a substrate, a buffer layer, an n-type AlInGaN layer, an AlInGaN superlattice layer having a V-pit, an n-region AlInGaN electron blocking layer having a V-pit, an AlInGaN-based multi-quantum well layer having a V-pit, a p-region AlInGaN electron blocking layer having a V-pit, and a p-type AlInGaN layer, characterized in that: The V-pit sidewall thickness of the n-region AlInGaN electron blocking layer with a V-pit is greater than the platform thickness; an n-type AlInGaN high-doping layer with a V-pit is contained between the n-region AlInGaN electron blocking layer with a V-pit and the AlInGaN-based multi-quantum well layer with a V-pit; the V-pit sidewall thickness of the p-region AlInGaN electron blocking layer with a V-pit is less than the platform thickness; a p-type AlInGaN high-doping layer with a merged V-pit is contained between the p-region AlInGaN electron blocking layer with a V-pit and the p-type AlInGaN layer; the Si doping concentration of the n-type AlInGaN high-doping layer with a V-pit is 1×10 19 ~5×10 20 cm -3 The Mg doping concentration of the p-type AlInGaN high-doped layer with the merged V pit is 3×10 19 ~1×10 21 cm -3 .

2. The epitaxial structure of the AlInGaN-based optoelectronic device according to claim 1, characterized in that: The bandgap width of the n-region AlInGaN electron blocking layer with the V-pit is greater than the bandgap widths of all quantum barriers in the AlInGaN-based multi-quantum well layer with the V-pit.

3. The epitaxial structure of the AlInGaN-based optoelectronic device according to claim 1, characterized in that: The bandgap width of the p-region AlInGaN electron blocking layer with the V-pit is greater than the bandgap widths of all quantum barriers in the AlInGaN-based multi-quantum well layer with the V-pit.

4. The epitaxial structure of the AlInGaN-based optoelectronic device according to claim 1, characterized in that: The platform is a growth plane and a polar plane, that is, a (0001) crystal plane family. The projection of the V-pit on the platform is a regular hexagon, and the sidewall of the V-pit is a semi-polar plane.

5. The epitaxial structure of the AlInGaN-based optoelectronic device according to claim 4, characterized in that: The semipolar plane belongs to the (1011) crystal plane family.

6. The epitaxial structure of the AlInGaN-based optoelectronic device according to claim 1, characterized in that: The platform thickness from the lower surface of the first quantum well to the upper surface of the last quantum well of the AlInGaN-based multi-quantum well layer with V-pits is d1, and the distance between the opposite sides of the regular hexagonal projection of the V-pit on the upper surface of the last quantum well is d2. The relationship between the two satisfies d2>d1×2tan28°, and the units of d1 and d2 are nm.

7. The epitaxial structure of an AlInGaN-based optoelectronic device according to claim 1 or 6, characterized in that: The ratio of the sum of the areas of all regular hexagonal projections of the V-pit on the upper surface of the final quantum well to the area of the upper surface of the final quantum well is δ, and the value of δ ranges from 15% to 50%.

8. The epitaxial structure of an AlInGaN-based optoelectronic device according to claim 1 or 6, characterized in that: The density of the V pits on the surface of the last quantum well is ρ, that is, the number of V pits per unit area, and the ρ value range is 1×10 8 cm -2 ~1×10 10 cm -2 .

9. The epitaxial structure of the AlInGaN-based optoelectronic device according to claim 1, characterized in that: The substrate is one of Al2O3, SiC, GaN or Si.

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