Light-emitting diode with improved brightness and preparation method thereof

Abstract

The present disclosure provides a light-emitting diode (LED) with enhanced brightness and a method for its fabrication, belonging to the field of optoelectronic manufacturing technology. The LED comprises: a first substrate, a reflector layer, a first transparent conductive layer, an ohmic contact layer, and an epitaxial layer; the first substrate, the reflector layer, the first transparent conductive layer, and the epitaxial layer are stacked in sequence; the first transparent conductive layer has a plurality of grooves on its surface adjacent to the epitaxial layer, the grooves being spaced apart; and the ohmic contact layer includes block structures positioned within the grooves. Embodiments of the present disclosure can reduce light absorption by the semiconductor layer, thereby enhancing the brightness of the LED.

Description

Technical Field

[0001] The present disclosure relates to the field of optoelectronic manufacturing technology, and in particular to a light-emitting diode with improved brightness and a preparation method thereof. Background Art

[0002] Light emitting diodes (LEDs) are a highly influential new product in the optoelectronics industry. They have the characteristics of small size, long service life, rich colors, and low energy consumption. They are widely used in lighting, display screens, signal lights, backlight sources, toys and other fields.

[0003] A light-emitting diode typically consists of a substrate, an n-type layer, a light-emitting layer, a p-type layer, a p-electrode, and an n-electrode. These three layers are stacked in sequence, with the n-electrode located on the surface of the n-type layer facing away from the substrate. The p-electrode is located on the surface of the substrate facing away from the p-type layer, and the p-electrode is connected to the p-type layer via a via.

[0004] Since the p-type layer includes a current spreading layer, an ohmic contact layer, and a p-type confinement layer sequentially stacked on the substrate, and the ohmic contact layer and the current spreading layer absorb light, thus affecting the brightness of the light-emitting diode. Summary of the Invention

[0005] The embodiments of the present disclosure provide a light-emitting diode with improved brightness and a method for manufacturing the same, which can reduce the absorption of light by the semiconductor layer and improve the brightness of the light-emitting diode. The technical solution is as follows:

[0006] On the one hand, an embodiment of the present disclosure provides a light-emitting diode with improved brightness, wherein the light-emitting diode includes: a first substrate, a reflector layer, a first transparent conductive layer, an ohmic contact layer and an epitaxial layer; the first substrate, the reflector layer, the first transparent conductive layer and the epitaxial layer are stacked in sequence; the first transparent conductive layer has a plurality of grooves on a surface close to the epitaxial layer, and the plurality of grooves are distributed at intervals; the ohmic contact layer includes a block structure located in the plurality of grooves.

[0007] Optionally, the thickness of the first transparent conductive layer is 5 nm to 500 nm, and the depth of the groove is no greater than the thickness of the first transparent conductive layer.

[0008] Optionally, the plurality of grooves are distributed along edges of the first transparent conductive layer.

[0009] Optionally, the reflector layer includes a metal layer, a second transparent conductive layer and a transparent insulating layer stacked in sequence on the first substrate; the transparent insulating layer has a via hole, and the second transparent conductive layer is connected to the first transparent conductive layer through the via hole, the refractive index of the transparent insulating layer is different from the refractive index of the first transparent conductive layer, and the refractive index of the transparent insulating layer is different from the refractive index of the second transparent conductive layer.

[0010] Optionally, the transparent insulating layer has a plurality of via holes, and the plurality of via holes at least partially overlap with orthographic projections of the plurality of grooves on the first substrate.

[0011] Optionally, both the first transparent conductive layer and the second transparent conductive layer are indium tin oxide film layers or indium zinc oxide film layers.

[0012] Optionally, the transparent insulating layer is an aluminum oxide layer, a silicon oxide layer or a magnesium fluoride layer.

[0013] On the other hand, an embodiment of the present disclosure also provides a method for preparing a light-emitting diode with improved brightness, the preparation method comprising: providing a second substrate; forming an epitaxial layer, an ohmic contact layer, a first transparent conductive layer and a reflector layer on the second substrate, wherein the first transparent conductive layer has a plurality of grooves on a surface close to the epitaxial layer, the plurality of grooves are spaced apart, and the ohmic contact layer includes a block structure located in the plurality of grooves; bonding the first substrate to the surface of the reflector layer away from the second substrate, and removing the second substrate.

[0014] Optionally, the ohmic contact layer is formed in the following manner: forming an ohmic contact layer on the epitaxial layer; and etching the ohmic contact layer to form a plurality of the block structures.

[0015] Optionally, the reflector layer is formed in the following manner: a transparent insulating layer is formed on the surface of the first transparent conductive layer, the transparent insulating layer having a via hole exposing the first transparent conductive layer; a second transparent conductive layer is formed on the surface of the transparent insulating layer, the second transparent conductive layer is connected to the first transparent conductive layer through the via hole, the refractive index of the transparent insulating layer is different from that of the first transparent conductive layer, and the refractive index of the transparent insulating layer is different from that of the second transparent conductive layer; and a metal layer is formed on the surface of the second transparent conductive layer.

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

[0017] The light-emitting diode of the disclosed embodiment includes a first substrate, a reflector layer, a first transparent conductive layer, and an epitaxial layer stacked in sequence. The ohmic contact layer includes a plurality of block structures located in grooves, and the plurality of block structures are connected to the surface of the epitaxial layer, i.e., the plurality of block structures are embedded in the first transparent conductive layer.

[0018] Compared with the entire ohmic contact layer in the related art, by dispersing the ohmic contact layer into multiple block structures and distributing the multiple block structures at intervals on the first semiconductor layer, the area of ​​the ohmic contact layer can be effectively reduced, thereby reducing the ohmic contact layer's absorption of light; at the same time, the first transparent conductive layer is used to replace the current spreading layer, and the first transparent conductive layer is used for current spreading. Since the current spreading layer is removed, the current spreading layer's absorption of light is reduced, thereby further improving the brightness of the light-emitting diode. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0020] Figure 1 is a structural schematic diagram of a light emitting diode provided by an embodiment of the present disclosure;

[0021] Figure 2 is a schematic diagram of a first transparent conductive layer provided by an embodiment of the present disclosure;

[0022] Figure 3 This is a flow chart of a method for preparing a light emitting diode provided in an embodiment of the present disclosure.

[0023] The descriptions of the marks in the figure are as follows:

[0024] 10. Substrate;

[0025] 20. epitaxial layer; 21. first transparent conductive layer; 210. groove; 22. first semiconductor layer; 23. multi-quantum well layer; 24. second semiconductor layer; 25. bulk structure;

[0026] 30. Reflector layer; 31. Metal layer; 32. Second transparent conductive layer; 33. Transparent insulating layer; 330. Via hole;

[0027] 41. First electrode; 42. Second electrode;

[0028] 50. Bonding layer. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0030] Figure 1 Schematic diagram of the structure of a light emitting diode provided by an embodiment of the present disclosure. Figure 1 As shown, the light emitting diode includes: a substrate 10 , a reflector layer 30 , a first transparent conductive layer 21 , an ohmic contact layer and an epitaxial layer 20 .

[0031] like Figure 1 As shown, a first substrate 10, a reflective mirror layer 30, a first transparent conductive layer 21, and an epitaxial layer 20 are stacked in sequence. The first transparent conductive layer 21 has a plurality of grooves 210 disposed at intervals on its surface near the epitaxial layer 20. The ohmic contact layer includes block structures 25 located within the plurality of grooves 210, and the plurality of block structures 25 are connected to the surface of the epitaxial layer 20.

[0032] The light-emitting diode of the embodiment of the present disclosure includes a first substrate 10, a reflector layer 30, a first transparent conductive layer 21, and an epitaxial layer 20 stacked in sequence. The ohmic contact layer includes block structures 25 located in a plurality of grooves 210, and the plurality of block structures 25 are embedded in the first transparent conductive layer 21.

[0033] Compared with the entire ohmic contact layer in the related art, by dispersing the ohmic contact layer into multiple block structures 25 and distributing the multiple block structures 25 at intervals on the first semiconductor layer 22, the area of ​​the ohmic contact layer can be effectively reduced, thereby reducing the absorption of light by the ohmic contact layer; at the same time, the first transparent conductive layer 21 is used to replace the current expansion layer, and the first transparent conductive layer 21 is used for current expansion. Since the current expansion layer is removed, the absorption of light by the current expansion layer is reduced, thereby further improving the brightness of the light-emitting diode.

[0034] Optionally, the first substrate 10 is a silicon substrate or a silicon carbide substrate. The first substrate 10 can be a flat substrate or a patterned substrate.

[0035] As an example, in the embodiment of the present disclosure, the first substrate 10 is a silicon substrate. Silicon substrate has better heat dissipation performance than GaAs, is a commonly used substrate, has mature technology and is low in cost.

[0036] In the embodiment of the present disclosure, Figure 1 As shown, the epitaxial layer 20 includes a first semiconductor layer 22, a multi-quantum well layer 23, and a second semiconductor layer 24 sequentially stacked on a first transparent conductive layer 21. A first electrode 41 is provided on a surface of the first substrate 10 away from the first semiconductor layer 22, and a second electrode 42 is provided on a surface of the second semiconductor layer 24.

[0037] One of the first semiconductor layer 22 and the second semiconductor layer 24 is a p-type layer, and the other of the first semiconductor layer 22 and the second semiconductor layer 24 is an n-type layer.

[0038] As an example, the first semiconductor layer 22 is a p-type layer, the first electrode 41 is a p-type electrode, the second semiconductor layer 24 is an n-type layer, and the second electrode 42 is an n-type electrode.

[0039] Optionally, the first semiconductor layer 22 is a p-type AlInP layer, and the thickness of the p-type AlInP layer may be 0.5 μm to 3 μm.

[0040] Optionally, the multi-quantum well layer 23 includes alternately grown AlGaInP quantum well layers and AlGaInP quantum barrier layers, wherein the multi-quantum well layer 23 may include 3 to 8 periods of alternately stacked AlGaInP quantum well layers and AlGaInP quantum barrier layers.

[0041] As an example, in the embodiment of the present disclosure, the multi-quantum well layer 23 includes five periods of alternately stacked AlGaInP quantum well layers and AlGaInP quantum barrier layers.

[0042] Optionally, the thickness of the multi-quantum well layer 23 may be 150 nm to 200 nm.

[0043] Optionally, the second semiconductor layer 24 is an n-type AlGaInP layer, and the thickness of the n-type AlGaInP layer may be 0.5 μm to 3 μm.

[0044] Optionally, the thickness of the first transparent conductive layer 21 is 5 nm to 500 nm, and the depth of the groove 210 is no greater than the thickness of the first transparent conductive layer 21 .

[0045] In this way, a first transparent conductive layer 21 is provided on the surface of the first semiconductor layer 22 to cover the plurality of block structures 25, so that the block structures 25 are embedded in the first transparent conductive layer 21, so that the first transparent conductive layer 21 and the block structures 25 are more stably connected, so that the electrodes can form good ohmic contact with the block structures 25 through the first transparent conductive layer 21.

[0046] For example, the thickness of the first transparent conductive layer 21 may be 60 nm, and the depth of the groove 210 may be 30 nm.

[0047] In some other implementations, the depth of the groove 210 may be equal to the thickness of the first transparent conductive layer 21 , that is, the groove 210 passes through the first transparent conductive layer 21 .

[0048] For example, the thickness of the first transparent conductive layer 21 may be 60 nm, and the depth of the groove 210 may be 60 nm.

[0049] If the thickness of the first transparent conductive layer 21 is too thin, it will affect the current contact between the block structure 25 and the electrode. If the thickness of the first transparent conductive layer 21 is too thick, it will increase the absorption of light by the first transparent conductive layer 21, thereby reducing the luminous efficiency of the light-emitting diode.

[0050] Figure 2 Schematic diagram of a first transparent conductive layer provided by an embodiment of the present disclosure. Figure 2 As shown, a plurality of grooves 210 are distributed along the edge of the first transparent conductive layer 21 .

[0051] The edge of the first transparent conductive layer 21 may refer to the outer contour of the orthographic projection of the first transparent conductive layer 21 on the first substrate 10. For example, if the outer contour of the orthographic projection of the first transparent conductive layer 21 is a rectangle, the grooves 210 may be distributed at the corners of the rectangle, or the grooves 210 may be distributed at intervals along the sides of the rectangle. In other words, the block structures 25 are also distributed along the edge of the first transparent conductive layer 21. Since the orthographic projections of the first transparent conductive layer 21 and the epitaxial layer 20 on the first substrate 10 overlap, the block structures 25 are also distributed along the edge of the epitaxial layer 20.

[0052] In this way, the block structure 25 is set at the edge of the epitaxial layer 20, that is, no ohmic contact layer is set in the middle area of ​​the epitaxial layer 20, which can reduce the amount of light absorbed by the middle area of ​​the epitaxial layer 20, so that more light can be reflected by the reflector layer 30 and then emitted, thereby improving the luminous brightness of the chip.

[0053] Alternatively, as Figure 1 As shown, the reflector layer 30 includes a metal layer 31 , a second transparent conductive layer 32 and a transparent insulating layer 33 sequentially stacked on the first substrate 10 .

[0054] like Figure 1 As shown, the transparent insulating layer 33 has a via hole 330 exposing the first transparent conductive layer 21, and the second transparent conductive layer 32 is connected to the first transparent conductive layer 21 through the via hole 330. The refractive index of the transparent insulating layer 33 is different from that of the first transparent conductive layer 21, and the refractive index of the transparent insulating layer 33 is different from that of the second transparent conductive layer 32.

[0055] In the embodiment of the present disclosure, the first transparent conductive layer 21 and the transparent insulating layer 33 have different refractive indices, so that the interface between the first transparent conductive layer 21 and the transparent insulating layer 33 forms a reflective surface for light reflection. As a result, part of the light is reflected at the interface when it enters the transparent insulating layer 33 from the first transparent conductive layer 21, thereby increasing the light output of the chip.

[0056] The transparent insulating layer 33 and the second transparent conductive layer 32 have different refractive indices, so that the interface between the transparent insulating layer 33 and the second transparent conductive layer 32 forms a reflective surface for light. As a result, part of the light is reflected at the interface when it enters the second transparent conductive layer 32 from the transparent insulating layer 33, further increasing the light output of the chip.

[0057] Furthermore, a metal layer 31 is disposed beneath the second transparent conductive layer 32. The metal layer 31 exhibits excellent reflective properties, allowing light passing through the second transparent conductive layer 32 and the transparent insulating layer 33 to be reflected toward the light-emitting surface of the chip. The film structure formed by the metal layer 31, the first transparent conductive layer 21, the second transparent conductive layer 32, and the transparent insulating layer 33 allows light to be reflected three times, allowing most of the light to be reflected toward the light-emitting surface, thereby enhancing the brightness of the chip.

[0058] The refractive indices of the first transparent conductive layer and the second transparent conductive layer may be the same or different. Furthermore, the refractive indices of the first transparent conductive layer and the second transparent conductive layer may both be lower than the refractive index of the transparent insulating layer, or both may be higher than the refractive index of the transparent insulating layer. The specific refractive indices may be determined based on actual conditions and are not limited in the presently disclosed embodiments.

[0059] For example, the thickness of the second transparent conductive layer 32 is 5 nm to 500 nm. For example, the thickness of the second transparent conductive layer 32 may be 300 nm.

[0060] If the second transparent conductive layer 32 is too thin, it will affect the current contact between the block structure 25 and the electrode. If the second transparent conductive layer 32 is too thick, it will increase the absorption of light by the second transparent conductive layer 32, thereby reducing the luminous efficiency of the light-emitting diode.

[0061] For example, the thickness of the transparent insulating layer 33 is 100 nm to 600 nm. For example, the thickness of the second transparent conductive layer 32 may be 500 nm.

[0062] If the transparent insulating layer 33 is too thin, it is difficult to form a reflective surface at the interface with the transparent conductive layer. If the transparent insulating layer 33 is too thick, the transparent insulating layer 33 absorbs light more, thereby reducing the luminous efficiency of the light-emitting diode.

[0063] Alternatively, as Figure 1 As shown, the transparent insulating layer 33 has a plurality of via holes 330 , and the plurality of via holes 330 at least partially overlap with the orthographic projections of the plurality of grooves 210 on the first substrate 10 .

[0064] Because the second transparent conductive layer 32 is connected to the first transparent conductive layer 21 through the vias 330, the current density in the second transparent conductive layer 32 is higher at the locations of the vias 330. By arranging the vias 330 and the grooves 210 in correspondence, the block structures 25 are closer to the areas of the second transparent conductive layer 32 with higher current density, thereby facilitating the current conduction to each block structure 25.

[0065] Optionally, the first transparent conductive layer 21 and the second transparent conductive layer 32 are both indium tin oxide film layers or indium zinc oxide film layers.

[0066] Indium tin oxide (ITO) film has good transmittance and low resistivity. Using ITO film as the transparent conductive layer allows more light to be transmitted from the transparent conductive layer to the metal layer 31, reducing the amount of light absorbed, allowing more light to be reflected from the metal layer 31 to the light-emitting surface, thereby ensuring the light-emitting effect.

[0067] The indium zinc oxide (IZO) film has good transmittance and low resistivity. Using the IZO film as the transparent conductive layer allows more light to be transmitted from the transparent conductive layer to the metal layer 31, reducing the amount of light absorbed, allowing more light to be reflected from the metal layer 31 to the light-emitting surface, thereby ensuring the light-emitting effect.

[0068] Optionally, the transparent insulating layer 33 is an aluminum oxide layer, a silicon oxide layer, or a magnesium fluoride layer. For example, in the embodiment of the present disclosure, the transparent insulating layer 33 may be an aluminum oxide layer.

[0069] Figure 3 This is a flow chart of a method for preparing a light emitting diode provided by an embodiment of the present disclosure. Figure 1 As shown in the light emitting diode. Figure 3 As shown, the preparation method comprises:

[0070] S11: providing a second substrate.

[0071] The second substrate may be a GaAs wafer.

[0072] S12: forming an epitaxial layer, an ohmic contact layer, a first transparent conductive layer and a reflective mirror layer on the second substrate.

[0073] The surface of the first transparent conductive layer close to the epitaxial layer has a plurality of grooves, the plurality of grooves are distributed at intervals, and the ohmic contact layer includes block structures located in the plurality of grooves.

[0074] S13: bonding the first substrate to the surface of the reflector layer away from the second substrate, and removing the second substrate.

[0075] The light-emitting diode prepared by this preparation method includes a substrate, a reflector layer, a first transparent conductive layer and an epitaxial layer stacked in sequence. Among them, the ohmic contact layer includes a block structure located in a plurality of grooves, and the plurality of block structures are connected to the surface of the epitaxial layer, that is, the plurality of block structures are embedded in the first transparent conductive layer. Compared with the whole-surface ohmic contact layer in the related art, by dispersing the ohmic contact layer into a plurality of block structures and distributing the plurality of block structures at intervals on the first semiconductor layer, the area of ​​the ohmic contact layer can be effectively reduced, thereby reducing the absorption of light by the ohmic contact layer; at the same time, the first transparent conductive layer is used to replace the current spreading layer, and the first transparent conductive layer is used for current spreading. Since the current spreading layer is removed, the absorption of light by the current spreading layer is reduced, thereby further improving the brightness of the light-emitting diode.

[0076] In the embodiment of the present disclosure, the epitaxial layer may include: a first semiconductor layer, a multi-quantum well layer, and a second semiconductor layer.

[0077] Step S12 may include the following steps:

[0078] In the first step, a second semiconductor layer 24, a multi-quantum well layer 23, and a first semiconductor layer 22 are grown on a GaAs wafer.

[0079] In the embodiment of the present disclosure, the first semiconductor layer 22 is a p-type layer, and the second semiconductor layer 24 is an n-type layer.

[0080] Optionally, the first semiconductor layer 22 is a p-type AlInP layer, and the thickness of the p-type AlInP layer may be 0.5 μm to 3 μm.

[0081] Optionally, the multi-quantum well layer 23 includes alternately grown AlGaInP quantum well layers and AlGaInP quantum barrier layers, wherein the multi-quantum well layer 23 may include 3 to 8 periods of alternately stacked AlGaInP quantum well layers and AlGaInP quantum barrier layers.

[0082] As an example, in the embodiment of the present disclosure, the multi-quantum well layer 23 includes five periods of alternately stacked AlGaInP quantum well layers and AlGaInP quantum barrier layers.

[0083] Optionally, the thickness of the multi-quantum well layer 23 may be 150 nm to 200 nm.

[0084] Optionally, the second semiconductor layer 24 is an n-type AlGaInP layer, and the thickness of the n-type AlGaInP layer may be 0.5 μm to 3 μm.

[0085] In the first step, a buffer layer, an n-type roughening layer, and a current spreading layer may be grown before growing the second semiconductor layer 24 .

[0086] Illustratively, the thickness of the n-type roughening layer and the current spreading layer may be 1000 angstroms to 2000 angstroms.

[0087] Alternatively, the ohmic contact layer may be a p-type AlInP layer doped with Mg, wherein the doping concentration of Mg is 1×10 18 / cm 3 .

[0088] In the second step, an ohmic contact layer is formed on the epitaxial layer.

[0089] In the third step, the ohmic contact layer is etched to form a plurality of block structures 25 .

[0090] Specifically, the process may include forming a photoresist layer on the surface of the ohmic contact layer, forming a mask structure through coating, exposure, and development, and etching the ohmic contact layer by dry etching or wet etching to form a plurality of spaced block structures 25 .

[0091] In the fourth step, a first transparent conductive layer 21 is formed on the surface of the first semiconductor layer 22 and the surface of the block structure 25 .

[0092] Specifically, it may include: depositing the first transparent conductive layer 21 on the surface of the first semiconductor layer 22 and the surface of the block structure 25 by electron beam evaporation or sputtering.

[0093] In the embodiment of the present disclosure, two-stage electron beam evaporation is used, firstly depositing 10 nm at a low rate, and then switching to a high rate to deposit 50 nm, to form the first transparent conductive layer 21 of the desired thickness.

[0094] Exemplarily, the first transparent conductive layer 21 may be an ITO film layer or an IZO film layer.

[0095] In the fifth step, a reflective mirror layer 30 is formed on the surface of the first transparent conductive layer 21 .

[0096] The manufacturing of the reflector layer 30 may include the following steps:

[0097] First, a transparent insulating layer 33 is formed on the surface of the first transparent conductive layer 21 , wherein the transparent insulating layer 33 has a via hole 330 exposing the first transparent conductive layer 21 .

[0098] Specifically, the process may include: depositing a transparent insulating layer 33 on the surface of the first transparent conductive layer 21 , forming a mask structure by coating, exposing, and developing, and then wet etching the via hole 330 .

[0099] Exemplarily, the transparent insulating layer 33 may be an aluminum oxide layer, a silicon oxide layer, or a magnesium fluoride layer.

[0100] Next, the second transparent conductive layer 32 is formed on the surface of the transparent insulating layer 33 .

[0101] The second transparent conductive layer 32 is connected to the first transparent conductive layer 21 through the via 330 . The refractive index of the transparent insulating layer 33 is different from that of the first transparent conductive layer 21 . The refractive index of the transparent insulating layer 33 is different from that of the second transparent conductive layer 32 .

[0102] Specifically, it may include: depositing the second transparent conductive layer 32 on the surface of the transparent insulating layer 33 by electron beam evaporation or sputtering.

[0103] In the embodiment of the present disclosure, two-stage electron beam evaporation is used, firstly depositing 10 nm at a low rate, and then switching to a high rate to deposit 290 nm, to form the second transparent conductive layer 32 of the desired thickness.

[0104] For example, the second transparent conductive layer 32 may be an ITO film layer or an IZO film layer.

[0105] Finally, the metal layer 31 is formed on the surface of the second transparent conductive layer 32 .

[0106] When forming the metal layer 31 , the metal layer 31 may be formed on the surface of the second transparent conductive layer 32 by deposition, and then annealed at a low temperature.

[0107] The metal layer 31 may be a film layer made of a metal material with good reflective effect, such as Ag or Cu.

[0108] Step S13 includes bonding the first substrate 10 to the surface of the reflective mirror layer 30 away from the GaAs wafer, and removing the GaAs wafer.

[0109] The first substrate 10 is a silicon substrate or a silicon carbide substrate. The first substrate 10 can be a flat substrate or a patterned substrate.

[0110] As an example, in the embodiment of the present disclosure, the first substrate 10 is a silicon substrate. Silicon substrate has better heat dissipation performance than GaAs, is a commonly used substrate, has mature technology and is low in cost.

[0111] Specifically, the process may include: coating the surface of the first substrate 10 with a metal film, placing the metal film on the surface of the reflector layer 30 , and heating and pressurizing the epitaxial wafer to form a bonding layer 50 between the reflector layer 30 and the first substrate 10 .

[0112] After step S13 , the method may further include: forming a second electrode 42 on the surface of the second semiconductor layer 24 .

[0113] After the second electrode 42 is manufactured, a protective layer may be deposited. The protective layer may be Si 3 N 4 , so that the surface of the core particle and the cut sidewall are completely covered by the protective layer.

[0114] The first electrode 41 may be an electrode made of Au material.

[0115] Finally, the core particles are cut by laser forward scribing, blade back cutting, cracking, etc. to obtain light-emitting diodes.

[0116] The above description is merely an optional embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the scope of protection of the present disclosure.

Claims

1. A light emitting diode, characterized in that: The light-emitting diode comprises: a first substrate (10), a reflector layer (30), a first transparent conductive layer (21), an ohmic contact layer and an epitaxial layer (20); The first substrate (10), the reflector layer (30), the first transparent conductive layer (21) and the epitaxial layer (20) are stacked in sequence; The first transparent conductive layer (21) has a plurality of grooves (210) on a surface close to the epitaxial layer (20), the plurality of grooves (210) are distributed at intervals, and the plurality of grooves (210) are distributed along the edge of the first transparent conductive layer (21). When the outer contour of the orthographic projection of the first transparent conductive layer (21) on the first substrate (10) is a rectangle, the grooves (210) are distributed at the corners of the rectangle, or the grooves (210) are distributed at intervals along the sides of the rectangle. The thickness of the first transparent conductive layer (21) is 5 nm to 500 nm, and the depth of the grooves (210) is less than the thickness of the first transparent conductive layer (21); The ohmic contact layer comprises a block structure (25) located in the plurality of grooves (210), the cross section of the block structure (25) is rectangular, and the cross section of the block structure (25) is perpendicular to the first substrate (10); The reflector layer (30) comprises a metal layer (31), a second transparent conductive layer (32), and a transparent insulating layer (33) stacked in sequence on the first substrate (10); The transparent insulating layer (33) has a via hole (330), and the second transparent conductive layer (32) is connected to the first transparent conductive layer (21) through the via hole (330). The refractive index of the transparent insulating layer (33) is different from that of the first transparent conductive layer (21), and the refractive index of the transparent insulating layer (33) is different from that of the second transparent conductive layer (32). The transparent insulating layer (33) has a plurality of via holes (330), and the cross section of the via holes (330) is rectangular. The cross section of the via holes (330) is perpendicular to the first substrate (10). The orthographic projections of the plurality of via holes (330) and the plurality of grooves (210) on the first substrate (10) at least partially overlap. The grooves (210) have corresponding via holes (330), and the orthographic projections of the grooves (210) and the corresponding via holes (330) on the first substrate (10) at least partially overlap.

2. The light emitting diode according to claim 1, characterized in that The first transparent conductive layer (21) and the second transparent conductive layer (32) are both indium tin oxide film layers or indium zinc oxide film layers.

3. The light emitting diode according to claim 1, characterized in that The transparent insulating layer (33) is an aluminum oxide layer, a silicon oxide layer or a magnesium fluoride layer.

4. A method for preparing a light emitting diode, characterized in that: The preparation method comprises: providing a second substrate; An epitaxial layer, an ohmic contact layer, a first transparent conductive layer, and a reflector layer are formed on the second substrate. The first transparent conductive layer has a plurality of grooves on a surface close to the epitaxial layer. The plurality of grooves are spaced apart and distributed along the edge of the first transparent conductive layer. When the outer contour of the positive projection of the first transparent conductive layer on the second substrate is a rectangle, the grooves are distributed at the corners of the rectangle, or the grooves are spaced apart along the sides of the rectangle. The thickness of the first transparent conductive layer is 5nm to 500nm, the depth of the grooves is less than the thickness of the first transparent conductive layer, and the ohmic contact layer includes a block structure located in the plurality of grooves. The cross section of the block structure is a rectangle, and the cross section of the block structure is the same as that of the second substrate. The reflector layer comprises a stacked metal layer, a second transparent conductive layer and a transparent insulating layer; the transparent insulating layer has a via hole, the cross section of the via hole is rectangular, the cross section of the via hole is perpendicular to the second substrate, the second transparent conductive layer is connected to the first transparent conductive layer through the via hole, the refractive index of the transparent insulating layer is different from the refractive index of the first transparent conductive layer, the refractive index of the transparent insulating layer is different from the refractive index of the second transparent conductive layer, the transparent insulating layer has a plurality of via holes, the plurality of via holes and the orthographic projections of the plurality of grooves on the second substrate at least partially overlap, the grooves have corresponding via holes, and the orthographic projections of the grooves and the corresponding via holes on the second substrate at least partially overlap; A first substrate is bonded to a surface of the reflector layer away from the second substrate, and the second substrate is removed.

5. The preparation method according to claim 4, characterized in that The ohmic contact layer is formed in the following manner: forming an ohmic contact layer on the epitaxial layer; The ohmic contact layer is etched to form a plurality of block structures.

6. The preparation method according to claim 5, characterized in that The reflector layer is formed in the following manner: forming a transparent insulating layer on a surface of the first transparent conductive layer, wherein the transparent insulating layer has a via hole exposing the first transparent conductive layer; forming a second transparent conductive layer on the surface of the transparent insulating layer, the second transparent conductive layer being connected to the first transparent conductive layer through the via hole, the refractive index of the transparent insulating layer being different from that of the first transparent conductive layer, and the refractive index of the transparent insulating layer being different from that of the second transparent conductive layer; A metal layer is formed on the surface of the second transparent conductive layer.

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