Light emitting diode epitaxial structure and display panel

Abstract

The utility model relates to a kind of LED epitaxial structures, comprising: substrate;N type layer;Active layer is located on N type;P type layer, located on active layer;Wherein, the P type layer includes P type window layer, P type window layer includes several first laminated structure, each first laminated structure includes the GaInP layer, first GaP layer and second GaP layer of sequentially laminated, the P type doping concentration of second GaP layer in each first laminated structure is greater than the P type doping concentration of first GaP layer.The GaInP layer of the utility model has higher band gap, plays the role of optical window layer, can reduce light absorption loss;GaP has lower band gap, first GaP layer and second GaP layer play the role of buffer layer / transition layer, so the combination of GaInP layer, first GaP layer and second GaP layer realizes the balance of band matching and carrier transport efficiency, conducive to the efficient extension of current.

Description

Technical Field

[0001] This utility model relates to semiconductor devices, and in particular to an epitaxial structure of a light-emitting diode, and also to a display panel. Background Technology

[0002] Currently, the field of red LED (light-emitting diode) technology still faces many technical challenges. Exemplary red LEDs achieve carrier injection and recombination for luminescence through multilayer heterostructures. However, in practical applications, carriers are prone to nonradiative recombination or scattering at the interface, leading to decreased luminous efficiency and shortened device lifetime. Therefore, optimizing material structure and improving carrier transport efficiency and photon extraction capability remain key areas of focus for the development of red LED technology. Utility Model Content

[0003] Therefore, it is necessary to provide a light-emitting diode epitaxial structure with high carrier transport efficiency, as well as a display panel.

[0004] An epitaxial structure for a light-emitting diode includes: a substrate; an N-type layer located on one side of the substrate; an active layer located on the side of the N-type layer facing away from the substrate; and a P-type layer located on the side of the active layer facing away from the N-type layer. The P-type layer includes a P-type window layer, and the P-type window layer includes a plurality of first stacked structures. Each first stacked structure includes a GaInP layer, a first GaP layer, and a second GaP layer stacked sequentially. The barrier height of the second GaP layer in each first stacked structure is greater than the barrier height of the first GaP layer, and / or the P-type doping concentration of the second GaP layer in each first stacked structure is greater than the P-type doping concentration of the first GaP layer.

[0005] The aforementioned LED epitaxial structure comprises multiple repeating first stacked layers. The GaInP layer in these first stacked layers has a high bandgap, acting as an optical window layer to reduce light absorption loss. The GaP layer has a lower bandgap, and the first and second GaP layers act as buffer / transition layers. Therefore, the combination of the GaInP, first, and second GaP layers achieves a balance between bandgap matching and carrier transport efficiency, which is beneficial for efficient current expansion. Since each first stacked layer consists of films with different bandgap widths and barrier heights / doping concentrations, band bending and barriers can be formed at the interfaces of these films. Changes in the bandgap can modulate carrier transport characteristics, reduce lateral diffusion, achieve directional carrier transport, enhance the spatial uniformity of current expansion, and improve the carrier conduction efficiency of the device under operating voltage. Furthermore, the P-type window layer in the first stacked layer helps alleviate thermal stress, reducing cracks or defects caused by differences in thermal expansion coefficients, thus improving the reliability of the device in high-temperature environments.

[0006] In one embodiment, the P-type window layer further includes a GaP current spread layer, and each of the first stacked structures is located between the GaP current spread layer and the active layer.

[0007] In one embodiment, the thickness of the GaP current spreading layer is greater than the thickness of each of the first stacked structures.

[0008] In one embodiment, the P-type doping concentration of the GaP current spreading layer is greater than the P-type doping concentration of each of the second GaP layers.

[0009] In one embodiment, the barrier height of the GaP current spreading layer is greater than the barrier height of each of the second GaP layers.

[0010] In one embodiment, the thickness of the GaP current spreading layer is 3 to 5 micrometers.

[0011] In one embodiment, in each of the first stacked structures, the thickness of the GaInP layer is 50 to 150 nanometers, the thickness of the first GaP layer is 50 to 150 nanometers, and the thickness of the second GaP layer is 50 to 150 nanometers.

[0012] In one embodiment, the number of first stacked structures in the P-type window layer is 15-50.

[0013] In one embodiment, the total thickness of all first stacked structures in the P-type window layer is 2.3 to 5 micrometers.

[0014] In one embodiment, the GaInP layer is Ga x3 In （1-x3） For layer P, 0.5 ≤ x3 < 1.

[0015] In one embodiment, the P-type doping concentration of the GaInP layer is 1.5E18-3E18 atoms / cm³, the P-type doping concentration of the first GaP layer is 7E17-1E18 atoms / cm³, and the P-type doping concentration of the second GaP layer is 1.2E18-2.5E18 atoms / cm³.

[0016] In one embodiment, the bandgap of the GaInP layer is 1.82-2.23 eV, the bandgap of the first GaP layer is 2.25-2.26 eV, and the bandgap of the second GaP layer is 2.20-2.23 eV.

[0017] In one embodiment, the P-type window layer has a superlattice structure.

[0018] In one embodiment, the P-type doping concentration of the first stacked structure farther from the active layer is greater than the P-type doping concentration of the first stacked structure closer to the active layer.

[0019] In one embodiment, the barrier height of the first stacked structure farther from the active layer is greater than the barrier height of the first stacked structure closer to the active layer.

[0020] In one embodiment, the bandgap width of the first stack structure farther from the active layer is greater than the bandgap width of the first stack structure closer to the active layer.

[0021] In one embodiment, the P-type layer further includes a transition layer located between the P-type window layer and the active layer, the transition layer including a plurality of second stacked structures, each second stacked structure including an AlInP layer and an AlGaInP layer.

[0022] In one embodiment, in each of the second stacked structures, the AlInP layer has a thickness of 20 to 50 nanometers, and the AlGaInP layer has a thickness of 30 to 50 nanometers.

[0023] In one embodiment, the thickness of the transition layer is 100 to 500 nanometers.

[0024] In one embodiment, the AlInP layer is Al x1 In y P layer, the AlGaInP layer is Al x2 Ga （1-x2） 0.5In0.5P layer, x1>x2, 0.5≤x1<1, 0.15≤x2≤0.6, 0.3≤y≤0.5.

[0025] In one embodiment, in each of the second stacked structures, the P-type doping concentration of the AlInP layer is 1E17-3E17 atoms / cm³, and the P-type doping concentration of the AlGaInP layer is 3E17-7E17 atoms / cm³.

[0026] In one embodiment, the Al content of the second stacked structure farther from the active layer is less than the Al content of the second stacked structure closer to the active layer.

[0027] In one embodiment, the Al band of the second stacked structure farther from the active layer is smaller than the Al band of the second stacked structure closer to the active layer.

[0028] In one embodiment, the number of second stacked structures in the transition layer is 3-15.

[0029] In one embodiment, the P-type layer further includes a waveguide layer located between the active layer and the transition layer, and a confinement layer located between the waveguide layer and the transition layer, wherein the waveguide layer is an AlGaInP layer and the confinement layer is an AlInP layer.

[0030] In one embodiment, the light-emitting diode epitaxial structure is the epitaxial structure of a red LED.

[0031] A display panel includes a plurality of red LEDs, each of which has a light-emitting diode epitaxial structure as described in any of the preceding embodiments. Attached Figure Description

[0032] To better describe and illustrate embodiments and / or examples of the utility models disclosed herein, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed utility models, the currently described embodiments and / or examples, or the best mode of these utility models as currently understood.

[0033] Figure 1 This is a schematic diagram of the epitaxial structure of a light-emitting diode in one embodiment of this application.

[0034] Figure 2 This is a schematic diagram of the structure of the P-type window layer 41 in one embodiment of this application.

[0035] Figure 3 This is a schematic diagram of the structure of the P-type window layer 41 in another embodiment of this application.

[0036] Figure 4 This is a schematic diagram of the structure of the P-type layer 40 in one embodiment of this application.

[0037] Figure 5 This is a schematic diagram of the structure of the transition layer TL 42 in one embodiment of this application.

[0038] Figure 6 This is a schematic diagram of the structure of the P-type layer 40 in another embodiment of this application.

[0039] Figure 7 This is a schematic diagram of the structure of the P-type layer 40 in another embodiment of this application.

[0040] Figure 8 This is a schematic diagram of the structure of the N-type layer 20 in one embodiment of this application. Detailed Implementation

[0041] To facilitate understanding of this utility model, a more complete description will be given below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of this utility model. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of this utility model more thorough and complete.

[0042] Unless otherwise defined, 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 pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0043] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this utility model, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0044] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below” or “under” the other element or feature will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0045] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0046] Embodiments of the present invention are described herein with reference to cross-sectional views illustrating an ideal embodiment (and intermediate structure). Thus, variations in the shape shown can be anticipated due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the present invention should not be limited to the specific shapes of the regions shown herein, but include shape deviations due to, for example, manufacturing processes. For example, implantation regions shown as rectangular typically have rounded or curved features at their edges and / or implantation concentration gradients, rather than a binary change from implantation regions to non-implantation regions. Similarly, the buried regions formed by implantation can result in some implantation in the region between the buried region and the surface traversed during implantation. Therefore, the regions shown in the figures are substantially schematic, and their shapes are not intended to show the actual shapes of the regions of the device and are not intended to limit the scope of the present invention.

[0047] As mentioned in the background section, due to material interface defects and lattice mismatch, charge carriers are prone to nonradiative recombination or scattering at the interface, leading to decreased luminous efficiency and shortened device lifetime. Furthermore, the window layer, as the main channel for photon propagation, has a significant impact on light extraction efficiency due to its structural design and material properties. In current technologies, the propagation path of photons in the window layer is limited, easily resulting in light loss or poor directionality, further restricting the optical performance of the device. Simultaneously, the quality of the epitaxial layer is constrained by the difficulty of controlling the growth process, making it difficult to achieve a highly uniform crystal structure, thus affecting the stability and consistency of the device.

[0048] This application proposes a novel epitaxial structure for light-emitting diodes to optimize LED performance. See also... Figure 1 The light-emitting diode epitaxial structure includes a substrate 10, an N-type layer 20, an active layer 30, and a P-type layer 40 stacked sequentially. Each layer in the N-type layer 20 is N-type doped, and each layer in the P-type layer 40 is P-type doped. The P-type layer 40 includes a P-type window layer 41, which comprises several first stacked structures 410. (See [reference]). Figure 2Each first stacked structure 410 includes a GaInP layer 412, a first GaP layer 414, and a second GaP layer 416 stacked sequentially. The first GaP layer 414 is a lightly doped GaP layer, and the second GaP layer 416 is a heavily doped GaP layer. In each first stacked structure 410, the P-type doping concentration of the second GaP layer 416 is greater than the P-type doping concentration of the first GaP layer 414, and / or the barrier height of the second GaP layer 416 is greater than the barrier height of the first GaP layer 414. The barrier height of the second GaP layer 416 can be greater than the barrier height of the first GaP layer 414 by adjusting the P-type doping concentration of the second GaP layer 416 to be greater than the barrier height of the first GaP layer 414.

[0049] Traditional P-type GaP window layers typically use a single material, while the first stacked structure 410 of the P-type window layer 41 in this application adopts a multilayer heterogeneous structure of GaInP / GaP1 / GaP2. This structural design enables more precise carrier control and electrical performance optimization through bandgap engineering, and has significant material combination advantages compared to single-material P-type GaP window layers. Specifically, the GaInP layer 412 in the first stacked structure 410 has a high bandgap (typically about 1.85 eV), acting as an optical window layer to reduce light absorption loss; GaP has a low bandgap (typically about 1.35 eV). The first GaP layer 414 and the second GaP layer 416 act as buffer / transition layers. Therefore, the combination of the GaInP layer 412, the first GaP layer 414, and the second GaP layer 416 achieves a balance between bandgap matching and carrier transport efficiency, which is beneficial for efficient current expansion. Since each first stacked structure 410 is composed of films with different band gaps and doping concentrations, band bending and potential barriers can be formed at the interfaces of these films. The changes in the band can modulate the carrier transport characteristics, reduce lateral diffusion, achieve directional carrier transport, enhance the spatial uniformity of current spread, and improve the carrier conduction efficiency of the device under operating voltage. In addition, the first stacked structure 410 in the P-type window layer 41 helps to alleviate thermal stress, reduce cracks or defects caused by differences in thermal expansion coefficients, and improve the reliability of LEDs in high-temperature environments.

[0050] In one embodiment of this application, the P-type window layer 41 further includes a GaP current spreading layer 417, with each first stacked structure 410 located between the GaP current spreading layer 417 and the active layer 30. In one embodiment of this application, the P-type doping concentration of the GaP current spreading layer 417 is greater than the P-type doping concentration of each second GaP layer 416, resulting in a greater barrier height for the GaP current spreading layer 417 than for each second GaP layer 416. As part of the P-type window layer 41, the GaP current spreading layer 417 exhibits good P-type conductivity, further enhancing the vertical current spreading capability. In one embodiment of this application, the P-type doping concentration of the GaP current spreading layer 417 is 1E18-5E18 atoms / cm³, and the reduced doping helps to reduce the interface defect density and improve the stability of current spreading.

[0051] In one embodiment of this application, the P-type window layer 41 has a superlattice structure.

[0052] In one embodiment of this application, the number of first stacked structures 410 in the P-type window layer 41 is 15-50, that is, the alternation cycle (loop, also known as growth cycle) is 15-50.

[0053] In one embodiment of this application, the material of the GaInP layer 412 is Ga x3 In （1-x3） P, 0.5≤x3<1.

[0054] In one embodiment of this application, the p-type doping concentration of each film layer in each first stacked structure 410 is in the following order: GaInP layer 412 > second GaP layer 416 > first GaP layer 414. The highly doped GaInP layer 412 and the second GaP layer 416 improve conductivity, forming a good p-type conductive channel. The lightly doped first GaP layer 414 acts as a buffer, reducing interface scattering, and the overall structure helps to reduce contact resistance and series resistance. The doping gradient of GaInP layer 412 > second GaP layer 416 > first GaP layer 414 facilitates the efficient injection of charge carriers (holes) from the electrode to the active region, improving the carrier injection efficiency of the device.

[0055] In one embodiment of this application, the P-type doping concentration of the GaInP layer 142 is 1.5E18-3E18 atoms / cm³, the P-type doping concentration of the first GaP layer 144 is 7E17-1E18 atoms / cm³, and the P-type doping concentration of the second GaP layer 146 is 1.2E18-2.5E18 atoms / cm³.

[0056] In one embodiment of this application, the bandgap of the GaInP layer 142 is 1.82-2.23 eV, the bandgap of the first GaP layer 144 is 2.25-2.26 eV, and the bandgap of the second GaP layer 146 is 2.20-2.23 eV.

[0057] In one embodiment of this application, the P-type doping concentration of the first stacked structure 410 farther from the active layer 30 is greater than that of the first stacked structure 410 closer to the active layer 30. That is, as the growth cycle increases, the P-type doping concentration of the first stacked structure 410 gradually increases along the stacking direction. Furthermore, the bandgap width of the first stacked structure 410 farther from the active layer 30 is greater than that of the first stacked structure 410 closer to the active layer 30. That is, as the growth cycle increases, the bandgap width of the first stacked structure 410 gradually increases along the stacking direction.

[0058] In one embodiment of this application, in each first stacked structure 410, the thickness of the GaInP layer 412 is 50 to 150 nanometers, the thickness of the first GaP layer 414 is 50 to 150 nanometers, and the thickness of the second GaP layer 416 is 50 to 150 nanometers. In one embodiment of this application, the total thickness of all first stacked structures 410 in the P-type window layer 41 is 2.3 to 5 micrometers.

[0059] In one embodiment of this application, the thickness of the GaP current spreading layer 417 is greater than the thickness of each first stacked structure 410.

[0060] In one embodiment of this application, the thickness of the GaP current spreading layer 417 is 3 to 5 micrometers.

[0061] In one embodiment of this application, the P-type layer 40 further includes a transition layer TL 42 located between the P-type window layer 41 and the active layer 30, see [link to relevant documentation]. Figure 4 The transition layer TL 42 includes multiple second stacked structures 420, each second stacked structure 420 including a p-type doped AlInP layer 422 and a p-type doped AlGaInP layer 424.

[0062] The second stacked structure 420 of the transition layer TL 42 includes an AlInP layer 422 and an AlGaInP layer 424. In contrast, traditional transition layers TL use AlGaInP material, and the Al composition is usually adjusted only in one direction. It is difficult to simultaneously achieve lattice matching with the lower film layer (usually AlInP) and the upper film layer (P-type window layer 41) of the transition layer TL. Direct growth is prone to generating a large number of dislocations and defects, resulting in poor interface quality. However, the novel transition layer TL 42 of this application adopts a superlattice design. The dual-component structure of AlInP layer 422 and AlGaInP layer 424 allows for more flexible composition control. By combining changes in Al composition with control of the In / Ga ratio, a better lattice gradient match with the upper and lower films of the transition layer TL 42 can be achieved, thereby effectively reducing the interface defect density and improving crystal quality. On the other hand, by introducing AlInP, the thermal stability of the material can be enhanced, making it more suitable for devices operating in high-temperature environments.

[0063] In one embodiment of this application, the material of the AlInP layer 422 is Al. x1 In y The material of the P, AlGaInP layer 424 is Al x2 Ga （1-x2） The In / Ga ratio is 0.5In / 0.5P, where x1 > x2, 0.5 ≤ x1 < 1, 0.15 ≤ x2 ≤ 0.6, and 0.3 ≤ y ≤ 0.5. By adjusting the In / Ga ratio, the thermal expansion coefficients of the films above and below the transition layer TL 42 can be better matched, reducing cracks or peeling caused by thermal stress and improving the lattice quality of the epitaxial layer.

[0064] In one embodiment of this application, the Al content of the second stacked structure 420 farther from the active layer 30 is less than the Al content of the second stacked structure 420 closer to the active layer 30. That is, as the growth cycle increases, the Al content in the second stacked structure 420 gradually decreases along the stacking direction. By setting the Al content of the second stacked structure 420 farther from the active layer 30 to be less than the Al content of the second stacked structure 420 closer to the active layer 30, the Al band of the second stacked structure 420 farther from the active layer 30 is made smaller than the Al band of the second stacked structure 420 closer to the active layer 30.

[0065] Traditional transition layers (TLs) have relatively fixed band structures. However, the novel superlattice transition layer TL42 in this application, by adjusting the proportions of Al, In, and Ga, can create a gradient band structure through changes in the Al composition, thereby allowing for more precise control of carrier distribution. The high Al content region (AlInP layer 422) has a wider bandgap, which helps to form a potential barrier and optimize carrier confinement. Especially under p-type doping conditions, it helps to improve hole mobility and carrier transport efficiency, thereby improving the luminous efficiency and electrical performance of the device.

[0066] In one embodiment of this application, the number of second stacked structures 420 in the transition layer TL 42 is 3-15, that is, the alternation cycle (loop) is 3-15.

[0067] In one embodiment of this application, the P-type doping concentration of AlInP layer 422 is 1E17-3E17 atoms / cm³, and the P-type doping concentration of AlGaInP layer 424 is 3E17-7E17 atoms / cm³.

[0068] In one embodiment of this application, the thickness of the transition layer TL 42 is 150 to 500 nanometers.

[0069] In one embodiment of this application, in each second stacked structure 420, the AlInP layer 422 has a thickness of 20 to 50 nanometers, and the AlGaInP layer 424 has a thickness of 30 to 50 nanometers.

[0070] Furthermore, the synergistic mechanism of the two superlattice designs, the transition layer TL 42 and the P-type window layer 41, is as follows: First, carrier injection and transport synergy: the P-type window layer 41 provides high carrier injection efficiency, while the transition layer TL 42 provides a low-resistance transport path; together, they improve the carrier injection efficiency and electrical performance of the device. Second, lattice matching and material quality synergy: the P-type window layer 41 stabilizes the epitaxial structure, while the transition layer TL 42 buffers lattice mismatch; together, they improve the overall crystal quality and thermal stability of the epitaxial layer. Third, the P-type window layer 41 controls the photon propagation path, while the transition layer TL 42 optimizes the carrier distribution; together, they improve the optical performance and luminous efficiency of the device.

[0071] See Figure 6 In one embodiment of this application, the P-type layer 40 further includes a waveguide layer 402 and a cladding layer 404 located between the active layer 30 and the transition layer TL 42. The cladding layer 404 is located between the waveguide layer 402 and the transition layer TL 42. The waveguide layer 402 is made of P-type doped AlGaInP, and the cladding layer 404 is made of P-type doped AlInP.

[0072] See Figure 7 In one embodiment of this application, the P-type layer 40 further includes a P-type ohmic contact layer located on the P-type window layer 41, the material of which is P-type doped GaP.

[0073] See Figure 8In one embodiment of this application, the N-type layer 20 includes a buffer layer 201 on the substrate 10, a stop layer 202 on the buffer layer 201, an N-type ohmic contact layer 203 on the stop layer 202, a window layer 204 on the N-type ohmic contact layer 203, a confinement layer 205 on the window layer 204, and a waveguide layer 206 on the confinement layer 205. The buffer layer 201 is made of N-type doped GaAs, the stop layer (etched stop layer) 202 is made of N-type doped GaInP, the N-type ohmic contact layer 203 is made of N-type doped GaAs, the window layer 204 is made of N-type doped AlGaInP, the confinement layer 205 is made of N-type doped AlInP, and the waveguide layer 206 is made of N-type doped AlGaInP.

[0074] In one embodiment of this application, the aforementioned light-emitting diode epitaxial structure is the epitaxial structure of a red LED.

[0075] Based on all the above embodiments, this application optimizes the P-type window layer 41 and the transition layer TL 42, utilizing their synergistic effect to improve carrier injection efficiency while reducing the resistance path and increasing carrier transport efficiency, thereby improving the overall electrical performance of the device. Furthermore, the P-type window layer 41 also regulates the photon propagation path, contributing to optimized light output efficiency. The transition layer TL 42, by buffering lattice mismatch, improves the crystal quality and thermal stability of the epitaxial layer, thereby enhancing the reliability of the device.

[0076] This application provides a display panel including a plurality of red LEDs, which have the light-emitting diode epitaxial structure described in any of the foregoing embodiments.

[0077] In the description of this specification, references to terms such as "some embodiments," "other embodiments," and "ideal embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0078] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0079] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A light-emitting diode epitaxial structure, characterized in that, include: Substrate; An N-type layer is located on one side of the substrate; An active layer is located on the side of the N-type layer that faces away from the substrate; The P-type layer is located on the side of the active layer that is away from the N-type layer; The P-type layer includes a P-type window layer, which in turn includes several first stacked structures. Each first stacked structure includes a GaInP layer, a first GaP layer, and a second GaP layer stacked sequentially. The barrier height of the second GaP layer in each first stacked structure is greater than the barrier height of the first GaP layer.

2. The light-emitting diode epitaxial structure according to claim 1, characterized in that, The P-type window layer further includes a GaP current spread layer, each of the first stacked structures is located between the GaP current spread layer and the active layer, the thickness of the GaP current spread layer is greater than the thickness of each of the first stacked structures, and the barrier height of the GaP current spread layer is greater than the barrier height of each of the second GaP layers.

3. The light-emitting diode epitaxial structure according to claim 1, characterized in that, The number of the first stacked structures in the P-type window layer is 15-50.

4. The light-emitting diode epitaxial structure according to claim 1, characterized in that, The bandgap of the GaInP layer is 1.82-2.23 eV, the bandgap of the first GaP layer is 2.25-2.26 eV, and the bandgap of the second GaP layer is 2.20-2.23 eV.

5. The light-emitting diode epitaxial structure according to any one of claims 1-4, characterized in that, The P-type window layer has a superlattice structure; The barrier height of the first stacked structure farther from the active layer is greater than the barrier height of the first stacked structure closer to the active layer, and / or the bandgap width of the first stacked structure farther from the active layer is greater than the bandgap width of the first stacked structure closer to the active layer.

6. The light-emitting diode epitaxial structure according to claim 1, characterized in that, The P-type layer further includes a transition layer located between the P-type window layer and the active layer. The transition layer includes a plurality of second stacked structures, each of which includes an AlInP layer and an AlGaInP layer.

7. The light-emitting diode epitaxial structure according to claim 6, characterized in that, The Al band of the second stacked structure farther from the active layer is smaller than the Al band of the second stacked structure closer to the active layer; and / or the number of second stacked structures in the transition layer is 3-15.

8. The light-emitting diode epitaxial structure according to claim 6, characterized in that, The P-type layer further includes a waveguide layer located between the active layer and the transition layer, and a confinement layer located between the waveguide layer and the transition layer. The waveguide layer is an AlGaInP waveguide layer, and the confinement layer is an AlInP confinement layer.

9. The light-emitting diode epitaxial structure according to claim 1, characterized in that, The light-emitting diode epitaxial structure is the epitaxial structure of a red LED.

10. A display panel comprising a plurality of red LEDs, characterized in that, Each of the red LEDs has a light-emitting diode epitaxial structure as described in any one of claims 1-9.

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