High-brightness light-emitting diode and method for preparing same

Abstract

The present disclosure provides a high-brightness light-emitting diode and a method for manufacturing the same. The light-emitting diode includes: a substrate, an epitaxial layer, a recombination blocking layer, a first electrode, and a second electrode; the epitaxial layer includes a first semiconductor layer, a multi-quantum well layer, and a second semiconductor layer that are sequentially stacked on the substrate, and the epitaxial layer has a groove exposing the first semiconductor layer; the recombination blocking layer is located on the surface of the second semiconductor layer, and the recombination blocking layer includes a first blocking layer and a second blocking layer that are sequentially stacked, and the refractive index of the first blocking layer is higher than that of the second blocking layer; the first electrode is located in the groove and is electrically connected to the first semiconductor layer, and the second electrode is located on the surface of the recombination blocking layer and is electrically connected to the second semiconductor layer. The present disclosure can reduce the absorption of light by the electrodes and improve the brightness and luminous efficiency of the light-emitting diode.

Description

Technical Field

[0001] The present disclosure relates to the field of optoelectronic manufacturing technologies, and particularly to a high-brightness light-emitting diode and a preparation method thereof. Background Art

[0002] As a highly influential new product in the optoelectronic industry, a light-emitting diode (LED for short) has the characteristics of small volume, long service life, rich and colorful colors, low energy consumption, etc., and is widely used in the fields of lighting, display screens, signal lights, backlights, toys, etc.

[0003] In related technologies, a light-emitting diode includes a substrate, an epitaxial layer, and a current blocking layer stacked in sequence, and an electrode is usually disposed above the current blocking layer to block most of the current from directly entering the area where the epitaxial layer is connected to the electrode, so that more current extends to other areas of the epitaxial layer.

[0004] When the epitaxial layer emits light, the light easily passes through the epitaxial layer and the current blocking layer in sequence, irradiates onto the surface of the electrode, and is absorbed by the electrode, thereby reducing the brightness and luminous efficiency of the light-emitting diode. Summary of the Invention

[0005] Embodiments of the present disclosure provide a high-brightness light-emitting diode and a preparation method thereof, which can reduce the absorption of light by the electrode and improve the brightness and luminous efficiency of the light-emitting diode. The technical solution is as follows:

[0006] Embodiments of the present disclosure provide a light-emitting diode, which includes: a substrate, an epitaxial layer, a composite blocking layer, and a second electrode; the composite blocking layer is located on the surface of the epitaxial layer, the composite blocking layer includes a first blocking layer and a second blocking layer stacked in sequence, and the refractive index of the first blocking layer is higher than that of the second blocking layer; the second electrode is located on the surface of the composite blocking layer away from the substrate and is electrically connected to the epitaxial layer.

[0007] In one implementation manner of the embodiments of the present disclosure, the first blocking layer is an alumina layer, and the second blocking layer is a silica layer.

[0008] In another implementation manner of the embodiments of the present disclosure, the ratio of the thickness of the second blocking layer to the thickness of the first blocking layer is 2:1 to 5:1.

[0009] In another implementation manner of the embodiments of the present disclosure, the orthographic projection of the second electrode on the substrate is located within the orthographic projection of the composite blocking layer on the substrate.

[0010] In another implementation manner of the embodiment of the present disclosure, the epitaxial layer includes a first semiconductor layer, a multi-quantum well layer, and a second semiconductor layer that are sequentially stacked on the substrate. The surface of the second semiconductor layer away from the substrate has a receiving groove, and the composite barrier layer is located in the receiving groove; the light-emitting diode further includes a first electrode. The epitaxial layer has a groove exposing the first semiconductor layer, and the first electrode is located in the groove and electrically connected to the first semiconductor layer.

[0011] In another implementation manner of the embodiment of the present disclosure, the first barrier layer is located on the bottom surface and the side wall of the receiving groove, and the first barrier layer separates the second semiconductor layer and the second barrier layer.

[0012] In another implementation manner of the embodiment of the present disclosure, the included angle between the side wall and the bottom surface of the receiving groove is an obtuse angle.

[0013] In another implementation manner of the embodiment of the present disclosure, the surface of the composite barrier layer away from the substrate is flush with the surface of the second semiconductor layer away from the substrate.

[0014] In another implementation manner of the embodiment of the present disclosure, the light-emitting diode further includes a transparent conductive layer. The transparent conductive layer is located on the surfaces of the second semiconductor layer and the composite barrier layer away from the substrate, and the second electrode is located on the surface of the transparent conductive layer away from the substrate.

[0015] The embodiment of the present disclosure provides a method for manufacturing a light-emitting diode. The method for manufacturing the light-emitting diode includes: providing a substrate; forming an epitaxial layer on the substrate; forming a composite barrier layer on the surface of the epitaxial layer. The composite barrier layer includes a first barrier layer and a second barrier layer that are sequentially stacked, and the refractive index of the first barrier layer is higher than that of the second barrier layer; manufacturing a second electrode. The second electrode is located on the surface of the composite barrier layer and is electrically connected to the epitaxial layer.

[0016] The beneficial effects brought by the technical solution provided by the embodiment of the present disclosure at least include:

[0017] The light-emitting diode provided by an embodiment of the present disclosure includes a substrate and an epitaxial layer stacked in sequence. A composite barrier layer is provided on the surface of the epitaxial layer. The composite barrier layer includes a first barrier layer and a second barrier layer stacked in sequence, and the refractive index of the first barrier layer is higher than that of the second barrier layer. Moreover, a second electrode is provided on the composite barrier layer. In this way, when the epitaxial layer emits light, the emitted light will first enter the first barrier layer. When the light enters the second barrier layer from the first barrier layer, since the light is incident from a high-refractive-index film layer to a low-refractive-index film layer, when the incident angle of the light exceeds the critical angle defined by the first barrier layer and the second barrier layer, total internal reflection will occur, thereby preventing the light emitted by the epitaxial layer from entering the second barrier layer, and also preventing the second electrode located above the composite barrier layer from absorbing light. In this way, a part of the light radiated towards the electrode is reflected towards the substrate direction by the composite barrier layer, which can increase the amount of light emitted from the light-emitting surface, and also reduce the absorption of light by the electrode, improving the brightness and luminous efficiency of the light-emitting diode. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 is a schematic structural diagram of a light-emitting diode provided by an embodiment of the present disclosure;

[0020] Figure 2 is an optical path diagram of light in the composite barrier layer provided by an embodiment of the present disclosure;

[0021] Figure 3 is a flowchart of a preparation method of a light-emitting diode provided by an embodiment of the present disclosure.

[0022] The descriptions of the marks in the drawings are as follows:

[0023] 10. Substrate;

[0024] 20. Epitaxial layer; 21. First semiconductor layer; 22. Multi-quantum well layer; 23. Second semiconductor layer; 24. Groove; 25. Accommodating groove;

[0025] 30. Composite barrier layer; 31. First barrier layer; 32. Second barrier layer;

[0026] 41. First electrode; 42. Second electrode;

[0027] 50. Transparent conductive layer; 51. U-shaped GaN layer. Detailed Embodiments

[0028] To make the objectives, technical solutions and advantages of the present disclosure more apparent, the following further describes the embodiments of the present disclosure in detail with reference to the accompanying drawings.

[0029] Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings as understood by those of ordinary skill in the art to which the present disclosure pertains. The terms "first", "second", "third" and similar terms used in the specification and claims of the present patent application do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, the terms such as "a" or "an" do not denote a limitation of quantity, but mean that there is at least one. The terms such as "comprising" or "including" mean that the elements or items appearing before "comprising" or "including" cover the elements or items listed after "comprising" or "including" and their equivalents, without excluding other elements or items. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", "right", "top", "bottom" are only used to indicate relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationships may also change accordingly.

[0030] Figure 1 is a schematic structural diagram of a light-emitting diode provided by an embodiment of the present disclosure. As Figure 1 shown, the light-emitting diode includes: a substrate 10, an epitaxial layer 20, a composite barrier layer 30, and a second electrode 42;

[0031] As Figure 1 shown, the composite barrier layer 30 is located on the surface of the epitaxial layer 20. The composite barrier layer 30 includes a first barrier layer 31 and a second barrier layer 32 stacked in sequence, and the refractive index of the first barrier layer 31 is higher than that of the second barrier layer 32.

[0032] As Figure 1 shown, the second electrode 42 is located on the surface of the composite barrier layer 30 away from the substrate 10 and is electrically connected to the epitaxial layer 20.

[0033] The light-emitting diode provided by an embodiment of the present disclosure includes a substrate 10 and an epitaxial layer 20 stacked in sequence. A recombination blocking layer 30 is provided on the surface of the epitaxial layer 20. The recombination blocking layer 30 includes a first blocking layer 31 and a second blocking layer 32 stacked in sequence, and the refractive index of the first blocking layer 31 is higher than that of the second blocking layer 32. Moreover, the second electrode 42 is on the recombination blocking layer 30. When the epitaxial layer 20 emits light, the emitted light will first enter the first blocking layer 31. When the light enters the second blocking layer 32 from the first blocking layer 31, since the light is incident from a high-refractive-index film layer to a low-refractive-index film layer, when the incident angle of the light exceeds the critical angle defined by the first blocking layer 31 and the second blocking layer 32, total internal reflection will occur, thereby preventing the light emitted by the epitaxial layer 20 from entering the second blocking layer 32 and also preventing the second electrode 42 located above the recombination blocking layer 30 from absorbing light. In this way, a part of the light radiated towards the electrode is reflected towards the direction of the substrate 10 through the recombination blocking layer, which can increase the amount of light emitted from the light-emitting surface and also reduce the absorption of light by the electrode, improving the brightness and luminous efficiency of the light-emitting diode.

[0034] Wherein, the critical angle defined by the first blocking layer 31 and the second blocking layer 32 can be determined by the refractive index of the first blocking layer 31 and the refractive index of the second blocking layer 32. The calculation formula for the critical angle is: θ = arcsin(n2 / n1).

[0035] In the formula, θ is the critical angle, n2 is the refractive index of the second blocking layer 32, and n1 is the refractive index of the second blocking layer 32.

[0036] Optionally, the substrate 10 is a sapphire substrate 10. The sapphire substrate 10 has a relatively high light transmittance, that is, the substrate 10 is a transparent substrate. Moreover, the sapphire material is relatively hard and has relatively stable chemical properties, enabling the light-emitting diode to have good luminous effects and stability.

[0037] As Figure 1 shown, the epitaxial layer 20 includes a first semiconductor layer 21, a multi-quantum well layer 22, and a second semiconductor layer 23 stacked in sequence on the substrate 10. The surface of the second semiconductor layer 23 has a groove 24 exposing the first semiconductor layer 21.

[0038] Wherein, the light-emitting diode further includes a first electrode 41. The first electrode 41 is located in the groove 24 and is electrically connected to the first semiconductor layer 21. The recombination blocking layer 30 is on the second semiconductor layer 23. The second electrode 42 is on the surface of the recombination blocking layer 30 and is connected to the second semiconductor layer 23.

[0039] In an embodiment of the present disclosure, one of the first semiconductor layer 21 and the second semiconductor layer 23 is a p-type layer, and the other of the first semiconductor layer 21 and the second semiconductor layer 23 is an n-type layer.

[0040] Exemplarily, the first semiconductor layer 21 is an n-type layer, and the second semiconductor layer 23 is a p-type layer.

[0041] Optionally, the first semiconductor layer 21 is an n-type GaN layer doped with silicon. The thickness of the n-type GaN layer can be from 0.5 μm to 3 μm.

[0042] Optionally, the multiple quantum well layer 22 includes alternately grown InGaN quantum well layers and GaN quantum barrier layers. Among them, the multiple quantum well layer 22 can include 3 to 8 periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0043] As an example, in the embodiments of the present disclosure, the multiple quantum well layer 22 includes 5 periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0044] Optionally, the thickness of the multiple quantum well layer 22 can be from 150 nm to 200 nm.

[0045] Optionally, the second semiconductor layer 23 is a p-type GaN layer doped with magnesium. The thickness of the p-type GaN layer can be from 0.5 μm to 3 μm.

[0046] In the embodiments of the present disclosure, the first barrier layer 31 is an alumina layer, and the second barrier layer 32 is a silica layer.

[0047] Among them, the refractive index of alumina is 1.76, and the refractive index of silica is 1.5. Based on the foregoing calculation formula of the critical angle, the critical angle can be calculated to be 60°.

[0048] Since the refractive index of the alumina layer is higher than that of the silica layer, when light enters the silica layer from the alumina layer, if the incident angle of the light exceeds 60°, total internal reflection will occur at the interface between the alumina layer and the silica layer. In this way, the light with an incident angle exceeding 60° will be reflected to the light-emitting surface where the substrate 10 is located; and it also avoids the light from entering the second electrode and being absorbed by the second electrode, thereby increasing the amount of light emitted from the light-emitting surface and reducing the absorption of light by the electrode, and improving the brightness and luminous efficiency of the light-emitting diode.

[0049] Optionally, the ratio of the thickness of the second barrier layer to the thickness of the first barrier layer is from 2:1 to 5:1.

[0050] Exemplarily, the first barrier layer is an alumina layer, and the second barrier layer is a silica layer.

[0051] The silica layer is the film layer for blocking current in the composite barrier layer 30. Therefore, setting the thickness of the silica layer to be greater than the thickness of the alumina layer can ensure the current blocking effect of the composite barrier layer 30.

[0052] Exemplarily, the ratio of the thickness of the silicon oxide layer to the thickness of the aluminum oxide layer is 4:1.

[0053] Optionally, the orthographic projection of the second electrode 42 on the substrate 10 is located within the orthographic projection of the composite barrier layer 30 on the substrate 10.

[0054] By setting the orthographic projection of the composite barrier layer 30 to be larger than the orthographic projection of the second electrode, that is, allowing the composite barrier layer 30 to completely block the second electrode, and when the light emitted by the epitaxial layer 20 is at a certain incident angle, total internal reflection will occur at the composite barrier layer 30. Therefore, it can avoid the light directly incident on the second electrode and being absorbed, effectively reducing the amount of light absorption and improving the brightness and luminous efficiency of the light-emitting diode.

[0055] Optionally, as Figure 1 shown, the surface of the second semiconductor layer 23 away from the substrate 10 has a receiving groove 25, and the composite barrier layer 30 is located within the receiving groove 25.

[0056] As Figure 1 shown, the surface of the composite barrier layer 30 away from the substrate 10 is flush with the surface of the second semiconductor layer 23 away from the substrate 10.

[0057] By setting the composite barrier layer 30 within the receiving groove 25 and controlling the surface of the composite barrier layer 30 to be flush with the surface of the epitaxial layer 20, it is possible to prevent the composite barrier layer 30 from protruding from the surface of the epitaxial layer 20. In this way, the film layer or the second electrode formed on the surface of the composite barrier layer 30 can contact the epitaxial layer 20 and the composite barrier layer 30 more smoothly, preventing the film layer or the second electrode formed on the surface of the composite barrier layer 30 from breaking.

[0058] Optionally, as Figure 1 shown, the first barrier layer 31 is located on the bottom surface and the side wall of the receiving groove 25, and the first barrier layer 31 separates the second semiconductor layer 23 and the second barrier layer 32.

[0059] In the embodiments of the present disclosure, the first barrier layer 31 is laid on the bottom surface and the side wall of the receiving groove 25, that is, the first barrier layer 31 covers the inner wall surface of the receiving groove 25. By completely separating the second barrier layer 32 and the second semiconductor layer 23 by the first barrier layer 31, the light rays emitted from each position of the epitaxial layer 20 towards the composite barrier layer 30 can be reflected at the interface between the first barrier layer 31 and the second barrier layer 32, reducing the amount of light rays incident on the second electrode and improving the brightness of the light-emitting diode.

[0060] Optionally, as Figure 1 shown, the side wall of the receiving groove 25 is an inclined surface, and the angle between the side wall of the receiving groove 25 and the bottom surface of the receiving groove 25 is an obtuse angle.

[0061] Exemplarily, asFigure 1 As shown, the included angle between the side wall and the bottom surface of the accommodation groove 25 is 120°.

[0062] Figure 2 This is an optical path diagram of light in the composite barrier layer 30 provided by an embodiment of the present disclosure. As Figure 2 shown by the optical path indicated by X, when the incident angle of the light exceeds the critical angle, total internal reflection of the light will occur at the interface between the first barrier layer 31 and the second barrier layer 32.

[0063] When the incident angle of the light is less than the critical angle, the light will enter the second barrier layer 32 through the first barrier layer 31, and the optical path is as Figure 2 shown by Y, and after the light enters the second barrier layer 32, it will expand towards the side wall direction of the accommodation groove 25.

[0064] As Figure 2 shown, when the light is incident on the interface between the second barrier layer 32 and the first barrier layer 31 again, since the light is incident from a low refractive index film layer to a high refractive index film layer, at this time, the light will refract, and the refraction angle is less than the incident angle, so that the light deflects towards the normal direction, thereby making the light exit towards the substrate 10 again. Therefore, the amount of light exiting from the light exit surface can be increased, and the brightness and luminous efficiency of the light emitting diode can be improved.

[0065] Optionally, the depth of the accommodation groove 25 is 2000 Å to 3000 Å. Among them, the ratio of the thickness of the silicon oxide layer to the thickness of the aluminum oxide layer is 2:1 to 5:1.

[0066] Exemplarily, the depth of the accommodation groove 25 is 2500 Å, and the ratio of the thickness of the silicon oxide layer to the thickness of the aluminum oxide layer is 4:1. Correspondingly, the thickness of the silicon oxide layer can be 2000 Å, and the thickness of the aluminum oxide layer can be 500 Å.

[0067] In the embodiment of the present disclosure, as Figure 1 shown, the light emitting diode further includes a transparent conductive layer 50, the transparent conductive layer 50 is located on the surface of the second semiconductor layer 23 and the surface of the composite barrier layer 30 away from the substrate 10, and the second electrode 42 is located on the surface of the transparent conductive layer 50.

[0068] Optionally, the transparent conductive layer 50 is an indium tin oxide (Indium Tin Oxide, abbreviated as ITO) layer. The indium tin oxide layer has good transmittance and low resistivity. Using the indium tin oxide layer as the transparent conductive layer 50 can make more light transmit through the transparent conductive layer 50, thus ensuring the effect; at the same time, due to the low resistivity, it is also convenient for carrier conduction and improves the injection efficiency.

[0069] Optionally, the transparent conductive layer 50 is an indium zinc oxide (IZO) layer. The indium zinc oxide layer has good transmittance and low resistivity. Using the indium zinc oxide layer as the transparent conductive layer 50 allows more light to transmit through the transparent conductive layer 50, thus ensuring the effect. At the same time, due to the low resistivity, it is also convenient for carrier conduction and improves the injection efficiency.

[0070] Exemplarily, the thickness of the transparent conductive layer 50 can be 3000 angstroms to 6000 angstroms. For example, the thickness of the transparent conductive layer 50 is 4000 angstroms.

[0071] Optionally, as Figure 1 shown, the light-emitting diode further includes a U-shaped GaN layer 51, and the U-shaped GaN layer 51 is located between the sink substrate and the epitaxial layer.

[0072] Figure 3 is a flowchart of a method for manufacturing a light-emitting diode provided by an embodiment of the present disclosure. As Figure 3 shown, the manufacturing method includes:

[0073] S11: Provide a substrate 10.

[0074] S12: Form an epitaxial layer 20 on the substrate 10.

[0075] Among them, the epitaxial layer 20 includes a first semiconductor layer 21, a multi-quantum well layer 22, and a second semiconductor layer 23 that are sequentially stacked on the substrate 10, and the epitaxial layer 20 has a groove 24 exposing the first semiconductor layer 21.

[0076] S13: Form a composite barrier layer 30 on the surface of the epitaxial layer 20.

[0077] Among them, the composite barrier layer 30 is located on the surface of the second semiconductor layer 23, and the composite barrier layer 30 includes a first barrier layer 31 and a second barrier layer 32 that are sequentially stacked, and the refractive index of the first barrier layer 31 is higher than that of the second barrier layer 32.

[0078] S14: Fabricate a second electrode.

[0079] In the embodiment of the present disclosure, the light-emitting diode further includes a first electrode 41, the first electrode 41 is located in the groove 24 and is electrically connected to the first semiconductor layer 21, and the second electrode 42 is located on the surface of the composite barrier layer 30 and is electrically connected to the second semiconductor layer 23.

[0080] The light-emitting diode prepared by the method for preparing a light-emitting diode includes a substrate 10, a first semiconductor layer 21, a multi-quantum well layer 22, and a second semiconductor layer 23 stacked in sequence. Among them, the second semiconductor layer 23 is provided with a recombination barrier layer 30, and the recombination barrier layer 30 includes a first barrier layer 31 and a second barrier layer 32 stacked in sequence, and the refractive index of the first barrier layer 31 is higher than that of the second barrier layer 32. And, the second electrode 42 is disposed on the recombination barrier layer 30. In this way, when the epitaxial layer 20 emits light, the emitted light will first enter the first barrier layer 31. When the light enters the second barrier layer 32 from the first barrier layer 31, since the light is incident from a high refractive index film layer to a low refractive index film layer, when the incident angle of the light exceeds the critical angle defined by the first barrier layer 31 and the second barrier layer 32, total reflection will occur, thereby preventing the light emitted by the epitaxial layer 20 from entering the second barrier layer 32, and also preventing the second electrode located above the recombination barrier layer 30 from absorbing light. In this way, a part of the light radiated to the electrode is reflected in the direction of the substrate 10 through the recombination barrier layer, which can increase the amount of light emitted from the light-emitting surface, and also reduce the absorption of light by the electrode, improving the brightness and luminous efficiency of the light-emitting diode.

[0081] In step S11, the substrate 10 is a sapphire substrate 10, a silicon substrate 10, or a silicon carbide substrate 10. The substrate 10 can be a flat substrate 10 or a patterned substrate 10.

[0082] As an example, in the embodiment of the present disclosure, the substrate 10 is a sapphire substrate 10. The sapphire substrate 10 is a commonly used substrate 10 with mature technology and low cost. Specifically, it can be a patterned sapphire substrate 10 or a sapphire flat substrate 10.

[0083] Among them, the sapphire substrate 10 can be pretreated by placing the sapphire substrate 10 in a MOCVD (Metal-organic Chemical Vapor Deposition) reaction chamber and baking the sapphire substrate 10 for 12 minutes to 18 minutes. As an example, in the embodiment of the present disclosure, the sapphire substrate 10 is baked for 15 minutes.

[0084] Specifically, the baking temperature can be 1000°C to 1200°C, and the pressure in the MOCVD reaction chamber during baking can be 100 mbar to 200 mbar.

[0085] Growing the epitaxial layer 20 on the substrate 10 in step S12 may include: sequentially forming a first semiconductor layer 21, a multi-quantum well layer 22, and a second semiconductor layer 23 on the sapphire substrate 10 by MOCVD technology.

[0086] Among them, the first semiconductor layer 21 is an n-type layer, and the second semiconductor layer 23 is a p-type layer.

[0087] Optionally, the first semiconductor layer 21 is an n-type GaN layer doped with silicon. The thickness of the n-type GaN layer can be 0.5 μm to 3 μm.

[0088] The growth temperature of the n-type GaN layer can be 1000 °C to 1100 °C, and the growth pressure of the n-type GaN layer can be 100 torr to 300 torr.

[0089] Optionally, the multi-quantum well layer 22 includes alternately grown InGaN quantum well layers and GaN quantum barrier layers. Among them, the multi-quantum well layer 22 can include 3 to 8 periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0090] When growing the multi-quantum well layer 22, the pressure in the MOCVD reaction chamber is controlled at 200 torr. When growing the InGaN quantum well layer, the reaction chamber temperature is 760 °C to 780 °C. When growing the GaN quantum barrier layer, the reaction chamber temperature is 860 °C to 890 °C.

[0091] As an example, in the embodiments of the present disclosure, the multi-quantum well layer 22 includes 5 periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0092] Optionally, the thickness of the multi-quantum well layer 22 can be 150 nm to 200 nm.

[0093] Optionally, the second semiconductor layer 23 is a p-type GaN layer doped with magnesium. The thickness of the p-type GaN layer can be 0.5 μm to 3 μm.

[0094] When growing the p-type GaN layer, the growth pressure of the p-type GaN layer can be 200 Torr to 600 Torr, and the growth temperature of the p-type GaN layer can be 800 °C to 1000 °C.

[0095] After forming the epitaxial layer 20 in step S12, the preparation method further includes: etching the second semiconductor layer 23 to form a groove 24 exposing the first semiconductor layer 21.

[0096] Step S13 may include the following steps:

[0097] The first step is to etch a receiving groove 25 on the second semiconductor layer 23.

[0098] Exemplarily, the depth of the receiving groove 25 can be 2000 angstroms to 3000 angstroms.

[0099] The second step is to deposit and form a composite barrier layer 30 in the receiving groove 25.

[0100] The composite barrier layer 30 includes a first barrier layer 31 and a second barrier layer 32 which are stacked in sequence. Among them, the first barrier layer 31 can be an aluminum oxide layer with a high refractive index, and the second barrier layer 32 can be a silicon oxide layer with a low refractive index. After the two barrier layers are deposited, the surface of the silicon oxide layer is flush with the surface of the second semiconductor layer 23.

[0101] After forming the composite barrier layer 30, the manufacturing method may further include: sputtering and forming a transparent conductive layer 50 on the surface of the second semiconductor layer 23.

[0102] Exemplarily, the transparent conductive layer 50 can be an ITO layer or an IZO layer.

[0103] In step S13, it includes: fabricating a second electrode 42 on the surface of the transparent conductive layer 50 away from the substrate 10, and fabricating a first electrode 41 on the surface of the first semiconductor layer 21 in the groove 24.

[0104] Among them, the second electrode 42 located on the second semiconductor layer 23 has gold beryllium as the main component, and the first electrode 41 located on the first semiconductor layer 21 is evaporated with gold germanium as the base material. When evaporating the gold germanium alloy, it is also necessary to ensure the evaporation power to avoid the evaporation time exceeding seconds to prevent the deviation of the alloy composition, and annealing is performed.

[0105] In the embodiments of the present disclosure, after fabricating the first electrode and the second electrode, a protective layer can also be fabricated on the epitaxial layer 20.

[0106] Exemplarily, in the embodiments of the present disclosure, the protective layer can be a silicon oxide layer.

[0107] Finally, the sapphire substrate 10 can be invisibly cut and cleaved, and the invisible cutting and cleaving can preferably reduce the loss of brightness. Then, a light-emitting diode is obtained through testing.

[0108] The above is not any form of limitation to the present disclosure. Although the present disclosure has been disclosed as above through embodiments, it is not intended to limit the present disclosure. Any person skilled in the art, without departing from the scope of the technical solution of the present disclosure, can make some changes or modifications to the above-disclosed technical content to obtain equivalent embodiments with equivalent changes. However, as long as it does not depart from the content of the technical solution of the present disclosure, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present disclosure still fall within the scope of the technical solution of the present disclosure.

Claims

1. A light-emitting diode, characterized in that, The light-emitting diode includes: a substrate (10), an epitaxial layer (20), a recombination barrier layer (30), and a second electrode (42); The recombination barrier layer (30) is located on the surface of the epitaxial layer (20), and the recombination barrier layer (30) includes a first barrier layer (31) and a second barrier layer (32) stacked in sequence. The refractive index of the first barrier layer (31) is higher than that of the second barrier layer (32); The second electrode (42) is located on the surface of the recombination barrier layer (30) away from the substrate (10) and is electrically connected to the epitaxial layer (20); The epitaxial layer (20) includes a first semiconductor layer (21), a multi-quantum well layer (22), and a second semiconductor layer (23) stacked in sequence on the substrate (10). The surface of the second semiconductor layer (23) away from the substrate (10) has a receiving groove (25). The recombination barrier layer (30) is located in the receiving groove (25). The first barrier layer (31) is located on the bottom surface and the side wall of the receiving groove (25). The first barrier layer (31) separates the second semiconductor layer (23) from the second barrier layer (32). The angle between the side wall and the bottom surface of the receiving groove (25) is an obtuse angle; The depth of the receiving groove (25) is equal to the sum of the thicknesses of the first barrier layer (31) and the second barrier layer (32).

2. The light-emitting diode according to claim 1, wherein The first barrier layer (31) is an aluminum oxide layer, and the second barrier layer (32) is a silicon oxide layer.

3. The light-emitting diode according to claim 1, wherein The ratio of the thickness of the second barrier layer (32) to the thickness of the first barrier layer (31) is 2:1 to 5:

1.

4. The light-emitting diode according to claim 1, characterized in that, The orthographic projection of the second electrode (42) on the substrate (10) is located within the orthographic projection of the recombination barrier layer (30) on the substrate (10).

5. The light emitting diode according to any one of claims 1 to 4, characterized in that, The light-emitting diode further includes a first electrode (41). The epitaxial layer (20) has a groove (24) exposing the first semiconductor layer (21). The first electrode (41) is located in the groove (24) and is electrically connected to the first semiconductor layer (21).

6. The light-emitting diode according to claim 5, characterized in that, The surface of the recombination barrier layer (30) away from the substrate (10) is flush with the surface of the second semiconductor layer (23) away from the substrate (10).

7. The light-emitting diode according to claim 5, wherein The light-emitting diode further includes a transparent conductive layer (50). The transparent conductive layer (50) is located on the surfaces of the second semiconductor layer (23) and the recombination barrier layer (30) away from the substrate (10). The second electrode (42) is located on the surface of the transparent conductive layer (50) away from the substrate (10).

8. A method for preparing a light-emitting diode, characterized in that, The manufacturing method of the light-emitting diode includes: Providing a substrate; Forming an epitaxial layer on the substrate. The epitaxial layer includes a first semiconductor layer, a multi-quantum well layer, and a second semiconductor layer stacked in sequence on the substrate. The surface of the second semiconductor layer away from the substrate has a receiving groove; A composite barrier layer is formed on the surface of the epitaxial layer. The composite barrier layer includes a first barrier layer and a second barrier layer that are stacked in sequence. The refractive index of the first barrier layer is higher than that of the second barrier layer. The composite barrier layer is located in the accommodation groove. The first barrier layer is located on the bottom surface and the side wall of the accommodation groove. The first barrier layer separates the second semiconductor layer and the second barrier layer. The included angle between the side wall and the bottom surface of the accommodation groove is an obtuse angle. The depth of the accommodation groove is equal to the sum of the thicknesses of the first barrier layer and the second barrier layer; A second electrode is fabricated. The second electrode is located on the surface of the composite barrier layer and is electrically connected to the epitaxial layer.

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