Light emitting diode for improving light extraction efficiency, preparation method thereof and display panel

Abstract

The invention provides a light-emitting diode for improving light extraction efficiency, a preparation method thereof and a display panel, and belongs to the technical field of photoelectron manufacturing. The preparation method comprises the following steps: providing a substrate, wherein the surface of the substrate is provided with a pattern structure; forming an epitaxial layer covering the pattern structure on the surface of the substrate; and removing the substrate and coarsening the surface, close to the substrate, of the epitaxial layer so as to form an irregular coarsened surface on the epitaxial layer. The surface of the epitaxial layer can be further coarsened, the coarsening degree of the epitaxial layer is improved, and the light extraction efficiency of the light-emitting diode is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of optoelectronic manufacturing, and particularly to a light-emitting diode for improving light extraction efficiency, a preparation method thereof, and a display panel. 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 size, 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 generally includes a substrate and an epitaxial layer stacked in sequence. The epitaxial layer is located on the surface of the substrate. To improve the light extraction efficiency of the light-emitting diode, the substrate is removed from the epitaxial layer, and the surface of the epitaxial layer in contact with the substrate is roughened.

[0004] In related technologies, the surface of the epitaxial layer is generally roughened by wet etching. Due to the isotropic property of wet etching, the roughening degree of the surface of the epitaxial layer by this roughening method is limited, and it is difficult to further improve the light extraction efficiency of the light-emitting diode. Summary of the Invention

[0005] Embodiments of the present disclosure provide a light-emitting diode for improving light extraction efficiency, a preparation method thereof, and a display panel, which can further roughen the surface of the epitaxial layer, improve the roughening degree of the epitaxial layer, and improve the light extraction efficiency of the light-emitting diode. The technical solution is as follows:

[0006] Embodiments of the present disclosure provide a preparation method of a light-emitting diode, and the preparation method includes: providing a substrate, the surface of the substrate having a pattern structure; forming an epitaxial layer covering the pattern structure on the surface of the substrate; removing the substrate and roughening the surface of the epitaxial layer close to the substrate to form an irregular roughened surface on the epitaxial layer.

[0007] In another implementation manner of the embodiments of the present disclosure, the pattern structure includes protrusions or grooves arranged at intervals on the surface of the substrate.

[0008] In another implementation manner of the embodiments of the present disclosure, the height of the pattern structure is greater than or equal to 2 μm.

[0009] In another implementation manner of the embodiments of the present disclosure, roughening the surface of the epitaxial layer close to the substrate includes: etching the surface of the epitaxial layer stacked with the substrate layer with a KOH solution to form an irregular roughened surface on the surface of the epitaxial layer.

[0010] In another implementation manner of the embodiments of the present disclosure, roughening the surface of the epitaxial layer close to the substrate includes: forming a mask on the surface where the epitaxial layer and the substrate are stacked; etching the surface of the epitaxial layer through the mask to form an irregular roughened surface.

[0011] In another implementation manner of the embodiments of the present disclosure, the difference between the maximum height and the minimum height of the protruding portions of the roughened surface is greater than or equal to 1.5 μm.

[0012] The embodiments of the present disclosure provide a light-emitting diode, which includes an epitaxial layer. One surface of the epitaxial layer is a roughened surface, and the difference between the maximum height and the minimum height of the protruding portions of the roughened surface is greater than 1.5 μm.

[0013] In another implementation manner of the embodiments of the present disclosure, the minimum height of the protruding portions of the roughened surface is greater than or equal to 2 μm.

[0014] In another implementation manner of the embodiments of the present disclosure, the epitaxial layer includes a first semiconductor layer, a multi-quantum well layer, and a second semiconductor layer stacked in sequence, and the roughened surface is the surface of the first semiconductor layer away from the second semiconductor layer.

[0015] The embodiments of the present disclosure provide a display panel, which includes a light-emitting functional layer and a driving backplane. The light-emitting functional layer is located on the driving backplane and is electrically connected to the driving backplane. The light-emitting functional layer includes a plurality of the above-mentioned light-emitting diodes.

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

[0017] When preparing the light-emitting diode according to the preparation method of the light-emitting diode provided by the embodiments of the present disclosure, first, an epitaxial layer is formed on the surface of a substrate with a pattern structure. Since the epitaxial layer covers the pattern structure during growth, there will be protrusions or grooves on the surface of the grown epitaxial layer attached to the surface of the pattern structure, that is, the surface of the epitaxial layer is roughened once during the growth of the epitaxial layer; then, after removing the substrate, the surface of the epitaxial layer is directly roughened again. This not only makes the protrusions or grooves corresponding to the pattern structure on the surface of the epitaxial layer more irregular, but also can further form deeper grooves or higher protrusions on the surface of the epitaxial layer, thereby increasing the height extreme difference of the protruding portions of the roughened surface and making the surface of the epitaxial layer become a roughened surface with a large fluctuation amplitude and irregularity. And the rougher the surface of the epitaxial layer, the easier the light is to exit. Therefore, the light extraction efficiency of the light-emitting diode can be effectively improved. Description of the Drawings

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

[0019] Figure 1 is a schematic structural diagram of a light-emitting diode provided by the related art;

[0020] Figure 2 is a flowchart of a method for manufacturing a light-emitting diode provided by an embodiment of the present disclosure;

[0021] Figure 3 is a preparation state diagram of a light-emitting diode provided by an embodiment of the present disclosure;

[0022] Figure 4 is a preparation state diagram of a light-emitting diode provided by an embodiment of the present disclosure;

[0023] Figure 5 is a schematic structural diagram of a light-emitting diode provided by an embodiment of the present disclosure.

[0024] The descriptions of the marks in the figure are as follows:

[0025] 10. Substrate; 11. Pattern structure;

[0026] 20. Epitaxial layer; 21. First semiconductor layer; 22. Multi-quantum well layer; 23. Second semiconductor layer; 24. Roughened surface;

[0027] 30. Transparent conductive layer;

[0028] 40. Passivation layer;

[0029] 50. Electrode. Detailed implementation manners

[0030] To make the objectives, technical solutions, and advantages of the present disclosure clearer, the following will further describe the embodiments of the present disclosure in detail with reference to the accompanying drawings.

[0031] Unless otherwise defined, technical terms or scientific terms used herein shall have the ordinary meanings as understood by those of ordinary skill in the art to which this disclosure pertains. The terms "first", "second", "third", and similar terms used in the description and claims of this patent application of the present disclosure do not denote any order, quantity, or importance, but are merely used to distinguish different components. Similarly, terms such as "a" or "an" do not denote a quantity limitation, but rather indicate the presence of at least one. Terms such as "comprising" or "including" mean that the elements or items appearing before "comprising" or "including" encompass the elements or items listed after "comprising" or "including" and their equivalents, and do not exclude other elements or items. Terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Terms such as "upper", "lower", "left", "right", "top", "bottom", etc. 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.

[0032] Figure 1 is a schematic structural diagram of a light-emitting diode provided by the related art. As Figure 1 shown, the light-emitting diode in the related art includes an epitaxial layer 20 and an electrode 50 stacked in sequence. 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.

[0033] As Figure 1 shown, the surface of the second semiconductor layer 23 has a groove exposing the first semiconductor layer 21. A part of the electrode 50 is located in the groove and is electrically connected to the first semiconductor layer 21, and another part of the electrode 50 is located on the surface of the second semiconductor layer 23 and is electrically connected to the second semiconductor layer 23.

[0034] In the related art, wet etching is usually used to roughen the light-emitting surface of the epitaxial layer 20 to increase the light output of the light-emitting diode. Due to the isotropic nature of wet etching, the degree of roughening of the light-emitting surface in this etching method is limited.

[0035] As Figure 1 shown, although the light-emitting surface of the epitaxial layer 20 becomes a roughened surface 24 after wet etching. However, the maximum height h of the protruding portions on the roughened surface 24 is usually less than 1 μmm. This degree of roughening has a limited effect on increasing the light-emitting area and is difficult to effectively improve the light extraction efficiency of the light-emitting diode.

[0036] Therefore, an embodiment of the present disclosure provides a method for manufacturing a light-emitting diode. Figure 2 is a flowchart of a method for manufacturing a light-emitting diode provided by an embodiment of the present disclosure. As Figure 2 shown, the manufacturing method includes:

[0037] Step S11: Provide a substrate.

[0038] Wherein, the surface of the substrate has a pattern structure 11.

[0039] Exemplarily, the substrate can be a sapphire substrate, a GaAs substrate, a silicon substrate or a silicon carbide substrate.

[0040] Optionally, the pattern structure 11 includes protrusions or grooves arranged at intervals on the surface of the substrate.

[0041] Figure 3 It is a preparation state diagram of a light-emitting diode provided by an embodiment of the present disclosure. As Figure 3 shown, the pattern structure 11 on the surface of the substrate 10 includes a plurality of protrusions arranged at intervals. In this way, using the substrate as a template, the epitaxial layer 20 subsequently grown on the surface of the substrate 10 can also form protrusions or grooves corresponding to the pattern structure 11, so as to achieve the purpose of preliminarily roughening the surface of the epitaxial layer 20.

[0042] Exemplarily, the height of the pattern structure 11 is greater than or equal to 2 μm. As an example, when the pattern structure 11 is a protrusion, the height of the protrusion is greater than or equal to 2 μm.

[0043] By designing the height of the pattern structure 11 within the above range, it can be ensured that the size of the protrusions or grooves on the surface of the epitaxial layer 20 grown with the pattern structure 11 as a template also exceeds 2 μm, which can greatly improve the roughening degree of the surface of the epitaxial layer 20.

[0044] Step S12: Form an epitaxial layer 20 covering the pattern structure 11 on the surface of the substrate.

[0045] Exemplarily, as Figure 3 shown, the surface of the substrate has a plurality of protrusions arranged at intervals, and the plurality of protrusions constitute the pattern structure 11. The epitaxial layer 20 grows on the surface of the substrate, and the epitaxial layer 20 covers the plurality of protrusions. In this way, after removing the substrate, protrusions or grooves corresponding to the pattern structure 11 will be formed on the surface of the epitaxial layer 20 in contact with the substrate, thereby roughening the surface of the epitaxial layer 20.

[0046] Exemplarily, the epitaxial layer 20 includes a first semiconductor layer, a multi-quantum well layer and a second semiconductor layer stacked in sequence.

[0047] Growing the epitaxial layer 20 can include: sequentially forming a first semiconductor layer, a multi-quantum well layer and a second semiconductor layer on the substrate by MOCVD technology.

[0048] Wherein, one of the first semiconductor layer and the second semiconductor layer is an n-type layer, and the other of the first semiconductor layer and the second semiconductor layer is a p-type layer.

[0049] Exemplarily, the epitaxial layer 20 includes an n-type GaN layer, a multi-quantum well layer, and a p-type GaN layer that are stacked in sequence.

[0050] Optionally, the thickness of the n-type GaN layer can be 0.5 μm to 3 μm.

[0051] 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.

[0052] Optionally, the multi-quantum well layer includes alternately grown InGaN quantum well layers and GaN quantum barrier layers. Among them, the multi-quantum well layer can include 3 to 8 periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0053] When growing the multi-quantum well layer, 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.

[0054] As an example, in the embodiments of the present disclosure, the multi-quantum well layer includes 5 periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0055] Optionally, the thickness of the multi-quantum well layer can be 150 nm to 200 nm.

[0056] Optionally, the thickness of the p-type GaN layer can be 0.5 μm to 3 μm.

[0057] 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.

[0058] After step S12 grows the epitaxial layer 20, the following steps can also be included:

[0059] First step, etch the surface of the second semiconductor layer to form a groove that at least exposes the multi-quantum well layer.

[0060] Specifically, it can include: forming a mask on the surface of the second semiconductor layer by photolithography, and then using plasma etching to form a groove on the surface of the second semiconductor layer through the mask.

[0061] Among them, during the etching process, control the upper power of the etching equipment at 300 W to 600 W and the lower power at 100 W to 300 W.

[0062] Exemplarily, the groove depth is 1 μm to 2 μm.

[0063] In the second step, a transparent conductive layer 30 is formed on the surface of the second semiconductor layer away from the first semiconductor layer.

[0064] Exemplarily, the transparent conductive layer 30 may be an indium tin oxide (ITO) layer or an indium zinc oxide (IZO) layer.

[0065] As an example, the thickness of the transparent conductive layer 30 may be from 1000 angstroms to 5000 angstroms. For example, the thickness of the transparent conductive layer 30 is 2000 angstroms.

[0066] In the third step, a passivation layer 40 is formed on the surface of the transparent conductive layer 30 away from the substrate and in the grooves.

[0067] Optionally, the passivation layer 40 includes at least one of a silicon oxide layer, a silicon nitride layer, and a titanium oxide layer.

[0068] Exemplarily, the passivation layer 40 may be a silicon oxide layer. Among them, the thickness of the silicon oxide layer may be 5000 angstroms.

[0069] In the fourth step, the passivation layer 40 is etched to form through holes exposing the transparent conductive layer 30 and the grooves on the surface of the passivation layer 40.

[0070] Among them, the etching can be achieved by dry etching, or by photolithography combined with wet etching, such as H 3 PO 4 / H 2 SO 4 mixed solution for etching, or by laser front scribing.

[0071] In the fifth step, an electrode 50 is formed on the surface of the passivation layer 40 away from the substrate, and the electrode 50 is connected to the transparent conductive layer 30 and the first semiconductor layer in the groove through the through holes respectively.

[0072] Specifically, it may include: fabricating a p-electrode 50 and an n-electrode 50 by photolithography and evaporation methods.

[0073] Among them, the n-electrode 50 is located in the groove and is connected to the n-type layer through the through hole, and the p-electrode 50 is connected to the transparent conductive layer 30 through the through hole.

[0074] Step S13: Remove the substrate and roughen the surface of the epitaxial layer 20 close to the substrate to form an irregular roughened surface 24 on the epitaxial layer 20.

[0075] Among them, removing the substrate may include: bonding the electrode 50 to a temporary substrate, removing the substrate on the surface of the epitaxial layer 20 by laser lift-off or chemical means, and cleaning the exposed roughened surface 24 of the epitaxial layer 20.

[0076] When roughening the surface of the epitaxial layer 20 in the implementation of the present disclosure, the following two methods may be included:

[0077] In the first implementation method, the surface of the epitaxial layer 20 stacked with the substrate layer is etched with a KOH solution to form an irregular roughened surface 24 on the surface of the epitaxial layer 20.

[0078] Specifically, it includes: putting the temporary substrate of the light-emitting diode into a KOH solution with an epitaxial etching effect, soaking for 1 minute to 30 minutes and then taking it out and cleaning, so as to form an irregular roughened surface 24 on the surface of the epitaxial layer 20.

[0079] In this way, the surface of the epitaxial layer 20 is further etched with an alkaline solution, so that the protrusions or grooves formed on the surface of the epitaxial layer 20 are further eroded, and the regular pattern of the protrusions or grooves is destroyed, so that the surface of the roughened surface 24 is rougher, so as to form an irregular roughened surface 24 on the epitaxial layer 20.

[0080] Figure 4 It is a preparation state diagram of a light-emitting diode provided by an embodiment of the present disclosure. As Figure 4 shown, after removing the substrate, an irregular roughened surface 24 is formed on the surface of the epitaxial layer 20 by wet etching.

[0081] Exemplarily, as Figure 4 shown, the difference between the maximum height H1 and the minimum height H2 of the protruding part of the roughened surface 24 is greater than or equal to 1.5 μm.

[0082] In the roughened surface 24 of the epitaxial layer 20 prepared in the embodiment of the present disclosure, the heights of the protrusions are non-uniform, and the difference between the maximum height and the minimum height of the protrusions reaches more than 1.5 μm, indicating that the roughness of the roughened surface 24 of the epitaxial layer 20 is relatively large, which can effectively improve the light extraction efficiency of the light.

[0083] In the second implementation method, a mask plate is formed on the surface of the epitaxial layer 20 stacked with the substrate layer; the surface of the epitaxial layer 20 is etched through the mask plate to form an irregular roughened surface 24.

[0084] In this implementation method, the effect of metal self-aggregation can be utilized to form a metal mask plate, and then the roughened surface 24 of the epitaxial layer 20 is further etched by an etching method to destroy the regular protrusions or grooves on the roughened surface 24, so as to form an irregular roughened surface 24 on the epitaxial layer 20.

[0085] When preparing a light-emitting diode by the method for preparing a light-emitting diode provided in an embodiment of the present disclosure, first, an epitaxial layer 20 is formed on the surface of a substrate having a pattern structure 11. Since the epitaxial layer 20 covers the pattern structure 11 during growth, there will be protrusions or grooves on the surface of the grown epitaxial layer 20 attached to the pattern structure 11, that is, the surface of the epitaxial layer 20 is roughened once during the growth of the epitaxial layer 20. Then, after removing the substrate, the surface of the epitaxial layer 20 is roughened again directly. This not only makes the protrusions or grooves corresponding to the pattern structure 11 on the surface of the epitaxial layer 20 more irregular, but also can further form grooves with a greater depth or protrusions with a greater height on the surface of the epitaxial layer 20, thereby increasing the height difference value of the protrusion part of the roughened surface 24, and making the surface of the epitaxial layer 20 become a roughened surface 24 with a large fluctuation amplitude and irregularity. And the rougher the surface of the epitaxial layer 20 is, the easier the light is emitted. Therefore, the light extraction efficiency of the light-emitting diode can be effectively improved.

[0086] Figure 5 is a schematic structural diagram of a light-emitting diode provided in an embodiment of the present disclosure. As Figure 5 shown, the light-emitting diode includes an epitaxial layer 20. One surface of the epitaxial layer 20 is a roughened surface 24, and the difference between the maximum height and the minimum height of the protruding part of the roughened surface 24 is greater than 1.5 μm.

[0087] In the embodiment of the present disclosure, the epitaxial layer 20 is prepared by the preparation method described above, and the heights of the protrusions in the roughened surface 24 of the epitaxial layer 20 are non-uniform, and the difference between the maximum height and the minimum height of the protrusions reaches more than 1.5 μm, indicating that the roughness of the roughened surface 24 of the epitaxial layer 20 is relatively large, and the light extraction rate of light can be effectively improved.

[0088] Optionally, the minimum height of the protruding part of the roughened surface 24 is greater than or equal to 2 μm. Exemplarily, the minimum height of the protruding part of the roughened surface 24 is 3 μm.

[0089] In this way, the protrusion size on the roughened surface 24 of the epitaxial layer 20 exceeds 2 μm, which can greatly improve the roughening degree of the surface of the epitaxial layer 20, indicating that the roughness of the roughened surface 24 of the epitaxial layer 20 is relatively large, and the light extraction rate of light can be effectively improved.

[0090] Optionally, as Figure 5 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, and the roughened surface 24 is the surface of the first semiconductor layer 21 far from the second semiconductor layer 23

[0091] In the embodiment of the present disclosure, one of the first semiconductor layer and the second semiconductor layer is an n-type layer, and the other of the first semiconductor layer and the second semiconductor layer is a p-type layer.

[0092] Exemplarily, the first semiconductor layer is an n-type layer and the second semiconductor layer is a p-type layer.

[0093] Hereinafter, taking the epitaxial layer 20 as a blue light epitaxial structure as an example, the structures of each layer will be described exemplarily. In the blue light epitaxial structure, the p-type layer includes a p-type GaN layer.

[0094] Among them, the multi-quantum well layer may include alternately grown InGaN quantum well layers and GaN quantum barrier layers. The third light-emitting layer may include 3 to 8 periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0095] Among them, the n-type layer includes an n-type GaN layer.

[0096] Optionally, the thickness of the epitaxial layer 20 is 2 μm to 10 μm.

[0097] Exemplarily, the thickness of the epitaxial layer 20 is 6 μm.

[0098] Optionally, as Figure 5 shown, the light-emitting diode further includes a transparent conductive layer 30, and the transparent conductive layer 30 is located on the surface of the second semiconductor layer 23.

[0099] Among them, the transparent conductive layer 30 is a film layer for connecting with the electrode 50. In this way, the transparent conductive layer 30 can laterally expand the current injected by the electrode 50, enabling the current to be injected into each region of the epitaxial layer 20, thereby improving the light-emitting efficiency.

[0100] Exemplarily, the transparent conductive layer 30 may be an indium tin oxide layer or an indium zinc oxide layer. The indium tin oxide layer or the indium zinc oxide layer has good transmittance and low resistivity, which can enable more light to transmit through the transparent conductive layer 30, thus ensuring the light output effect; at the same time, due to the low resistivity, it is also convenient for carrier conduction and improves the injection efficiency.

[0101] As an example, the thickness of the transparent conductive layer 30 may be 1000 Å to 5000 Å. For example, the thickness of the transparent conductive layer 30 is 2000 Å.

[0102] Optionally, as Figure 5 shown, the surface of the second semiconductor layer 23 has a groove exposing the first semiconductor layer 21. The light-emitting diode further includes a passivation layer 40, and the passivation layer 40 is located in the groove and on the surface of the first semiconductor layer 21, and the passivation layer 40 covers the transparent conductive layer 30.

[0103] Optionally, the passivation layer 40 includes at least one of a silicon oxide layer, a silicon nitride layer, and a titanium oxide layer.

[0104] Exemplarily, the passivation layer 40 may be a silicon oxide layer.

[0105] Among them, the thickness of the silicon oxide layer can be 5000 angstroms.

[0106] Optionally, as Figure 5 shown, the light-emitting diode further includes at least two electrodes 50, and the at least two electrodes 50 are both located on the surface of the passivation layer 40 away from the epitaxial layer 20. The surface of the passivation layer 40 has through holes respectively exposing the bottom of the groove and the transparent conductive layer 30. One of the electrodes 50 is connected to the first semiconductor layer through the through hole, and the other electrode 50 is connected to the transparent conductive layer 30 through the through hole.

[0107] Optionally, the at least two electrodes 50 include a p electrode 50 and an n electrode 50. Among them, the p electrode 50 is used to connect to the p-type layer, and the n electrode 50 is used to connect to the n-type layer.

[0108] An embodiment of the present disclosure provides a display panel, which includes a light-emitting functional layer and a driving backplane. The light-emitting functional layer is located on the driving backplane and is electrically connected to the driving backplane. The light-emitting functional layer includes a plurality of light-emitting diodes as described above.

[0109] Optionally, the driving backplane can be a TFT (Thin Film Transistor) substrate. The driving backplane includes a plurality of driving circuits arranged in an array. Each driving circuit on the driving backplane includes at least 2 TFTs for controlling the light-emitting layer connected thereto to emit light.

[0110] Exemplarily, the driving circuit includes an active layer, a gate insulating layer, a gate layer, an interlayer dielectric layer, and a source-drain layer stacked on the substrate in sequence. The light-emitting layer is connected to the source-drain layer of the corresponding driving circuit.

[0111] Among them, the manufacturing material of the TFT of the driving backplane can be various materials such as polysilicon and metal oxide, and the embodiments of the present disclosure do not make limitations.

[0112] The display device can be any product or component with a display function such as a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame, a navigator, etc.

[0113] 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 can make some changes or modifications to equivalent embodiments by using the disclosed technical content without departing from the technical solution of the present disclosure. However, as long as it does not depart from the technical solution of the present disclosure, any simple modification, equivalent change, and modification made to the above embodiments according to the technical essence of the present disclosure still fall within the scope of the technical solution of the present disclosure.

Claims

1. A method for preparing a light emitting diode, characterized in that: The preparation method comprises: Providing a substrate (10), wherein a surface of the substrate (10) has a pattern structure (11); forming an epitaxial layer (20) covering the pattern structure (11) on the surface of the substrate (10); The substrate (10) is removed and the surface of the epitaxial layer (20) close to the substrate (10) is roughened to form an irregular roughened surface (24) on the epitaxial layer (20).

2. The preparation method according to claim 1, characterized in that: The pattern structure (11) comprises protrusions or grooves arranged at intervals on the surface of the substrate (10).

3. The preparation method according to claim 1, characterized in that: The height of the pattern structure (11) is greater than or equal to 2 μm.

4. The preparation method according to any one of claims 1 to 3, characterized in that: Roughening the surface of the epitaxial layer (20) close to the substrate (10) comprises: A KOH solution is used to etch the surface of the epitaxial layer (20) stacked with the substrate (10), thereby forming an irregular roughened surface (24) on the surface of the epitaxial layer (20).

5. The preparation method according to any one of claims 1 to 3, characterized in that: Roughening the surface of the epitaxial layer (20) close to the substrate (10) comprises: forming a mask on the surface where the epitaxial layer (20) and the substrate (10) are stacked; The surface of the epitaxial layer (20) is etched through the mask to form an irregular roughened surface (24).

6. The preparation method according to any one of claims 1 to 3, characterized in that: The difference between the maximum height and the minimum height of the protruding part of the roughened surface (24) is greater than or equal to 1.5 μm.

7. A light emitting diode, characterized in that: The light emitting diode comprises an epitaxial layer (20), a surface of the epitaxial layer (20) is a roughened surface (24), and the difference between the maximum height and the minimum height of the protruding part of the roughened surface (24) is greater than 1.5 μm.

8. The light emitting diode according to claim 7, characterized in that: The minimum height of the protruding portion of the roughened surface (24) is greater than or equal to 2 μm.

9. The light emitting diode according to claim 7 or 8, characterized in that: The epitaxial layer (20) comprises a first semiconductor layer (21), a multi-quantum well layer (22) and a second semiconductor layer (23) stacked in sequence, and the roughened surface (24) is a surface of the first semiconductor layer (21) away from the second semiconductor layer (23).

10. A display panel, characterized in that: The display panel includes a light-emitting functional layer and a driving backplane, the light-emitting functional layer is located on the driving backplane and is electrically connected to the driving backplane, and the light-emitting functional layer includes a plurality of light-emitting diodes as described in any one of claims 7 to 9.

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