A light emitting diode structure and preparation method thereof

Abstract

The present invention discloses a light-emitting diode structure and a preparation method thereof, wherein the light-emitting diode structure comprises: a light-emitting unit layer comprises a plurality of light-emitting units arranged at intervals; each light-emitting unit comprises a first semiconductor layer, a light-emitting layer and a second semiconductor layer arranged in layers; the second semiconductor layer comprises a first sub-region and a second sub-region, the second sub-region further comprises a central region and an edge region, the edge region comprises a first photonic crystal structure, the first photonic crystal structure and the light-emitting layer are arranged in a one-to-one correspondence; and / or, a plurality of second photonic crystal structures are located on a side of the light-emitting unit layer away from a substrate, the second photonic crystal structures and the light-emitting units are arranged in a one-to-one correspondence, and the vertical projection of the second photonic crystal structure on the substrate covers the vertical projection of the light-emitting unit on the substrate. The present invention can improve light utilization and collimation.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a light emitting diode structure and a preparation method thereof. Background Art

[0002] Light-emitting diodes (LEDs) have the advantages of long service life, low energy consumption, and high resolution, and are widely used in various fields. Micro Light Emitting Diode (Micro LED) generally refers to the technology of using LED light-emitting units with a size of 1~60μm to form a display array. Micro LED display panels generally include multiple LED pixels, i.e. light-emitting units. Currently, Micro LEDs are all isolated by ion beam etching (IBE), but the light emitted by each pixel unit is relatively scattered and the light utilization rate is low; the light convergence and collimation effects are not good. Summary of the invention

[0003] The present invention provides a light emitting diode structure and a preparation method thereof, which can improve light utilization efficiency and collimation.

[0004] According to one aspect of the present invention, there is provided a light emitting diode structure, comprising:

[0005] A light-emitting unit layer, the light-emitting unit layer is located on one side of the substrate; the light-emitting unit layer includes a plurality of light-emitting units arranged at intervals; each light-emitting unit includes a first semiconductor layer, a light-emitting layer and a second semiconductor layer arranged in a stacked manner, and the second semiconductor layer is located on a side of the first semiconductor layer away from the substrate;

[0006] The second semiconductor layer includes a first sub-region and a second sub-region, the second sub-region is located on a side of the first sub-region away from the substrate, the second sub-region also includes a central region and an edge region, the edge region surrounds the central region, the edge region includes a first photonic crystal structure, the first photonic crystal structure and the light-emitting layer are arranged in a one-to-one correspondence; and / or, multiple second photonic crystal structures, the second photonic crystal structure is located on a side of the light-emitting unit layer away from the substrate, the second photonic crystal structure and the light-emitting unit are arranged in a one-to-one correspondence, and the vertical projection of the second photonic crystal structure on the substrate covers the vertical projection of the light-emitting unit on the substrate.

[0007] Optionally, the light emitting diode structure further comprises:

[0008] A plurality of micro lenses, wherein the micro lenses are located on a side of the second photonic crystal structure away from the substrate; the refractive index of the material of the micro lenses is greater than the refractive index of the material of the second photonic crystal structure;

[0009] Each light-emitting unit corresponds to at least one microlens; the vertical projection of the microlens on the substrate covers the vertical projection of the second photonic crystal structure on the substrate.

[0010] Optionally, the first photonic crystal structure and the second photonic crystal structure include a plurality of nanocolumns arranged at intervals; the shape of the nanocolumns includes at least one of a cylinder, a truncated cone and a cone;

[0011] The arrangement of the plurality of nanorods includes one of a matrix arrangement, a staggered arrangement and a triangular arrangement.

[0012] Optionally, the distance between adjacent nanopillars is 200nm-700nm;

[0013] Along the direction from the substrate to the light-emitting unit layer, the height of the nanocolumns is 150nm-1000nm;

[0014] The angle between the side wall of the nanocolumn and the first surface of the nanocolumn is 60°-90°, and the first surface of the nanocolumn is the surface of the nanocolumn adjacent to the substrate.

[0015] Optionally, the light emitting diode structure further comprises:

[0016] A transparent conductive layer, a plurality of bonding layers and a plurality of first insulating layers;

[0017] The bonding layer is located on a side of the light-emitting unit adjacent to the substrate, and each bonding layer corresponds to one light-emitting unit; the light-emitting unit covers part of the bonding layer;

[0018] The first insulating layer is located on a side of the light-emitting unit away from the substrate, and the first insulating layer includes a through hole; each first insulating layer covers the side wall of the light-emitting unit, the side wall of the bonding layer, and the bonding layer not covered by the light-emitting unit; when the second semiconductor layer includes the first photonic crystal structure, the through hole penetrates from the surface of the first insulating layer away from the substrate to the central area of ​​the second sub-area; when the second semiconductor layer does not include the first photonic crystal structure, the through hole penetrates from the surface of the first insulating layer away from the substrate to the second semiconductor layer;

[0019] The transparent conductive layer is located on a side of the first insulating layer away from the substrate; the transparent conductive layer contacts the second semiconductor layer through the through hole; the transparent conductive layer covers the through hole, the first insulating layer and the substrate not covered by the first insulating layer.

[0020] Optionally, the light emitting diode structure further comprises:

[0021] a second insulating layer and a plurality of isolation layers;

[0022] The isolation layer is located on a side of the transparent conductive layer away from the substrate, the isolation layer covers a portion of the transparent conductive layer, and an isolation layer is arranged between adjacent light-emitting units;

[0023] The second insulating layer is located at a side of the isolation layer away from the substrate, and the second insulating layer covers the plurality of isolation layers and the transparent conductive layer not covered by the isolation layer.

[0024] According to another aspect of the present invention, there is provided a method for preparing a light emitting diode structure, comprising:

[0025] forming a substrate;

[0026] A light-emitting unit layer is formed on one side of the substrate; the light-emitting unit layer includes a plurality of light-emitting units arranged at intervals; each light-emitting unit includes a first semiconductor layer, a light-emitting layer and a second semiconductor layer arranged in a stacked manner, and the second semiconductor layer is located on a side of the first semiconductor layer away from the substrate;

[0027] A plurality of second photonic crystal structures are formed on the side of the light emitting unit layer away from the substrate; the second photonic crystal structures and the light emitting units are arranged one by one, and the vertical projection of the second photonic crystal structure on the substrate covers the vertical projection of the light emitting unit on the substrate.

[0028] According to another aspect of the present invention, there is provided a method for preparing a light emitting diode structure, comprising:

[0029] forming a substrate;

[0030] A light-emitting unit layer is formed on one side of the substrate; the light-emitting unit layer includes a plurality of light-emitting units arranged at intervals; each light-emitting unit includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer which are stacked, and the second semiconductor layer is located on a side of the first semiconductor layer away from the substrate; the second semiconductor layer includes a first sub-region and a second sub-region, and the second sub-region is located on a side of the first sub-region away from the substrate, and the second sub-region also includes a central region and an edge region, the edge region surrounds the central region, and the edge region includes a first photonic crystal structure, and the first photonic crystal structure and the light-emitting layer are arranged in a one-to-one correspondence.

[0031] According to another aspect of the present invention, there is provided a method for preparing a light emitting diode structure, comprising:

[0032] forming a substrate;

[0033] A light-emitting unit layer is formed on one side of the substrate; the light-emitting unit layer includes a plurality of light-emitting units arranged at intervals; each light-emitting unit includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer arranged in a stacked manner, the second semiconductor layer being located on a side of the first semiconductor layer away from the substrate; the second semiconductor layer includes a first sub-region and a second sub-region, the second sub-region being located on a side of the first sub-region away from the substrate, the second sub-region further including a central region and an edge region, the edge region surrounding the central region, the edge region including a first photonic crystal structure, and the first photonic crystal structure and the light-emitting layer being arranged in a one-to-one correspondence;

[0034] A plurality of second photonic crystal structures are formed on the side of the light emitting unit layer away from the substrate; the second photonic crystal structures and the light emitting units are arranged one by one, and the vertical projection of the second photonic crystal structure on the substrate covers the vertical projection of the light emitting unit on the substrate.

[0035] Optionally, after forming a plurality of second photonic crystal structures on a side of the light-emitting unit layer away from the substrate, the method further includes:

[0036] forming a plurality of micro lenses on a side of the second photonic crystal structure away from the substrate; the refractive index of the material of the micro lenses is greater than the refractive index of the material of the second photonic crystal structure;

[0037] Each light-emitting unit corresponds to at least one microlens; the vertical projection of the microlens on the substrate covers the vertical projection of the second photonic crystal structure on the substrate.

[0038] The light-emitting diode structure provided by the technical solution of the embodiment of the present invention includes: a light-emitting unit layer, the light-emitting unit layer is located on one side of a substrate; the light-emitting unit layer includes a plurality of light-emitting units arranged at intervals; each light-emitting unit includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer arranged in a stacked manner, the second semiconductor layer is located on a side of the first semiconductor layer away from the substrate; the second semiconductor layer includes a first sub-region and a second sub-region, the second sub-region is located on a side of the first sub-region away from the substrate, the second sub-region also includes a central region and an edge region, the edge region surrounds the central region, the edge region includes a first photonic crystal structure, the first photonic crystal structure and the light-emitting layer are arranged in a one-to-one correspondence; and / or, a plurality of second photonic crystal structures, the second photonic crystal structure is located on a side of the light-emitting unit layer away from the substrate, the second photonic crystal structure and the light-emitting unit are arranged in a one-to-one correspondence, and the vertical projection of the second photonic crystal structure on the substrate covers the vertical projection of the light-emitting unit on the substrate; the first photonic crystal structure and the second photonic crystal structure are used to suppress the lateral propagation of light emitted by the light-emitting unit, so that the light emitted by the light-emitting unit can only propagate along the direction of the light-emitting surface, thereby improving light utilization and collimation.

[0039] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, 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 invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 It is a structural schematic diagram of a light emitting diode provided in the first embodiment of the present invention.

[0042] Figure 2 It is a structural schematic diagram of another light emitting diode provided in the first embodiment of the present invention.

[0043] Figure 3 It is a structural schematic diagram of another light emitting diode provided in the first embodiment of the present invention.

[0044] Figure 4 It is a structural schematic diagram of a light-emitting unit provided in Embodiment 1 of the present invention.

[0045] Figure 5 It is a structural schematic diagram of another light-emitting unit provided in the first embodiment of the present invention.

[0046] Figure 6 It is a structural schematic diagram of another light emitting diode provided in the first embodiment of the present invention.

[0047] Figure 7-Figure 9 It is a schematic diagram of the structure of a photonic crystal provided in Example 1 of the present invention.

[0048] Figure 10-12 A schematic diagram of the arrangement of a photonic crystal provided in Embodiment 1 of the invention.

[0049] Fig.13 This is a flow chart of a method for preparing a light-emitting diode structure provided in the second embodiment of the present invention.

[0050] Figure 14-Figure 20 It is a schematic diagram of an intermediate structure of a light emitting diode structure provided in the second embodiment of the present invention.

[0051] Fig.21 It is a flow chart of a method for preparing a light emitting diode structure provided in the third embodiment of the present invention.

[0052] Fig. 22 It is a schematic diagram of an intermediate structure of a light emitting diode structure provided in the third embodiment of the present invention.

[0053] Fig.23 It is a flow chart of a method for preparing a light-emitting diode structure provided in Embodiment 4 of the present invention. DETAILED DESCRIPTION

[0054] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0055] It should be noted that the terms "first", "second", etc. in the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or devices.

[0056] Embodiment 1

[0057] An embodiment of the present invention provides a light emitting diode structure. Figure 1 is a schematic diagram of the structure of a light emitting diode provided in the first embodiment of the present invention, Figure 2 is a schematic diagram of the structure of another light emitting diode provided in the first embodiment of the present invention, Figure 3 is a schematic diagram of the structure of another light emitting diode provided in the first embodiment of the present invention, Figure 4 is a structural schematic diagram of a light-emitting unit provided in Embodiment 1 of the present invention, Figure 5 is a schematic diagram of the structure of another light-emitting unit provided in the first embodiment of the present invention, referring to Figure 1-Figure 5 , the light emitting diode structure includes:

[0058] The light-emitting unit layer 30 is located on one side of the substrate 10; the light-emitting unit layer 30 includes a plurality of light-emitting units 301 arranged at intervals; each light-emitting unit 301 includes a first semiconductor layer 31, a light-emitting layer 32, and a second semiconductor layer 33 arranged in a stacked manner, and the second semiconductor layer 33 is located on a side of the first semiconductor layer 31 away from the substrate 10;

[0059] The second semiconductor layer 33 includes a first sub-region 331 and a second sub-region 332, the second sub-region 332 is located on a side of the first sub-region 331 away from the substrate 10, the second sub-region 332 also includes a central region 01 and an edge region 02, the edge region 02 surrounds the central region 01, the edge region 02 includes a first photonic crystal structure 81, the first photonic crystal structure 81 and the light-emitting layer 32 are arranged in a one-to-one correspondence; and / or, a plurality of second photonic crystal structures 82, the second photonic crystal structure 82 is located on a side of the light-emitting unit layer 30 away from the substrate 10, the second photonic crystal structure 82 and the light-emitting unit 301 are arranged in a one-to-one correspondence, and the vertical projection of the second photonic crystal structure 82 on the substrate 10 covers the vertical projection of the light-emitting unit 301 on the substrate 10.

[0060] Among them, the light-emitting diode can be a Micro LED; the substrate 10 is a substrate with a driving circuit, and the substrate 10 includes a plurality of driving units, each driving unit is provided with a contact point 11, and the contact point 11 of the driving unit is provided in a one-to-one correspondence with the light-emitting unit 301, and the light-emitting unit 301 is provided directly above the contact point 11, and each light-emitting unit 301 can be independently controlled. Each light-emitting unit 301 includes a first semiconductor layer 31, a light-emitting layer 32, and a second semiconductor layer 33 arranged in a stacked manner, and the materials of the first semiconductor layer 31, the light-emitting layer 32, and the second semiconductor layer 33 are all III-V compound materials commonly used in the semiconductor industry; the first semiconductor layer 31 can be an N-type semiconductor layer or a P-type semiconductor layer, if the first semiconductor layer 31 is an N-type semiconductor layer, the second semiconductor layer 33 is a P-type semiconductor layer, and if the first semiconductor layer 31 is a P-type semiconductor layer, the second semiconductor layer 33 is an N-type semiconductor layer; the light-emitting unit 301 can be any one of a red light-emitting unit, a green light-emitting unit, or a blue light-emitting unit, and can be provided according to requirements.

[0061] Specifically, the edge region 02 of the second sub-region 332 of the second semiconductor layer 33 includes a first photonic crystal structure 81, and the second photonic crystal structure 82 is located on the side of the light-emitting unit layer 30 away from the substrate 10. The materials of the second photonic crystal structure 82 and the first photonic crystal structure 81 can be the same or different; the vertical projection of the second photonic crystal structure 82 on the substrate 10 covers the vertical projection of the light-emitting unit 301 on the substrate 10. By setting the first photonic crystal structure 81 and the second photonic crystal structure 82 of different refractive index materials, the propagation path and speed of light can be controlled to achieve a photonic band gap, and light with a specific frequency can pass through. The first photonic crystal structure 81 and the light-emitting layer 32 are arranged in a one-to-one correspondence, and the second photonic crystal structure 82 and the light-emitting unit 301 are arranged in a one-to-one correspondence, so that the light emitted by the light-emitting unit 301 can only propagate along the direction of the light-emitting surface. The light-emitting surface is the surface of the light-emitting unit layer 30 away from the substrate 10, which can effectively suppress the lateral propagation of light emitted by the light-emitting unit 301 and improve light utilization and collimation.

[0062] The light-emitting diode structure provided by the technical solution of the embodiment of the present invention includes: a light-emitting unit layer 30, the light-emitting unit layer 30 is located on one side of the substrate 10; the light-emitting unit layer 30 includes a plurality of light-emitting units 301 arranged at intervals; each light-emitting unit 301 includes a first semiconductor layer 31, a light-emitting layer 32, and a second semiconductor layer 33 arranged in a stacked manner, and the second semiconductor layer 33 is located on a side of the first semiconductor layer 31 away from the substrate 10; the second semiconductor layer 33 includes a first sub-region 331 and a second sub-region 332, the second sub-region 332 is located on a side of the first sub-region 331 away from the substrate 10, and the second sub-region 332 also includes a central region 01 and an edge region 02, the edge region 02 surrounds the central region 01, and the edge region 02 surrounds the central region 01. Region 02 includes a first photonic crystal structure 81, which is arranged in a one-to-one correspondence with the light-emitting layer 32; and / or, a plurality of second photonic crystal structures 82, which are located on the side of the light-emitting unit layer 30 away from the substrate 10, and the second photonic crystal structures 82 and the light-emitting units 301 are arranged in a one-to-one correspondence, and the vertical projection of the second photonic crystal structure 82 on the substrate 10 covers the vertical projection of the light-emitting unit 301 on the substrate 10; the first photonic crystal structure 81 and the second photonic crystal structure 82 are used to suppress the lateral propagation of light emitted by the light-emitting unit, so that the light emitted by the light-emitting unit 301 can be propagated along the direction of the light-emitting surface, thereby improving light utilization and collimation.

[0063] Optional, reference Figure 1-Figure 3 The light-emitting diode structure also includes: a plurality of microlenses 90, the microlenses 90 are located on the side of the second photonic crystal structure 82 away from the substrate 10; the refractive index of the material of the microlens 90 is greater than the refractive index of the material of the second photonic crystal structure 82; each light-emitting unit 301 corresponds to at least one microlens 90; the vertical projection of the microlens 90 on the substrate 10 covers the vertical projection of the second photonic crystal structure 82 on the substrate 10.

[0064] The shape of the microlens 90 may be hemispherical or truncated cone; each light emitting unit 301 corresponds to at least one microlens 90. For example, Figure 1-Figure 3 Each light emitting unit 301 corresponds to one micro lens 90, or, Figure 6 is a schematic diagram of the structure of another light emitting diode provided in the first embodiment of the present invention, referring to Figure 6 A plurality of small-sized microlenses 91 are arranged on the curved surface of the microlens 90 away from the substrate 10, and any size of the small-sized microlenses 91 is smaller than the microlens 90. Figure 6 Just as an example, Figure 1-Figure 3A plurality of small-sized microlenses 91 can be provided on the basis of the light emitting diode, which can improve the light utilization rate and collimation of the light emitting diode. In some embodiments, the microlenses 90 composed of inorganic or organic materials are formed by mask patterning, photolithography, and then etching. In some embodiments, the microlenses 90 composed of organic materials are formed by mask patterning, photolithography, and then performing a thermal reflow process at high temperature and etching.

[0065] Specifically, the second photonic crystal structure 82 includes a plurality of nanocolumns arranged at intervals, and microlenses 90 are filled between adjacent nanocolumns. The refractive index of the material of the microlens 90 is greater than the refractive index of the material of the second photonic crystal structure 82, which is beneficial to light collimation and improves small-angle light emission; the material of the second photonic crystal structure 82 and the material of the microlens are arranged alternately, which can make the light utilization rate of the second photonic crystal structure 82 higher and the collimation better; the microlens 90 is arranged one-to-one with the second photonic crystal structure 82, and the surface of the microlens 90 away from the substrate 10 is a curved surface, which can further converge and / or collimate the light; the microlens 90 is an important optical element, and the microlens 90 can reduce scattering, internal reflection, absorption, etc., and can effectively improve the light utilization rate and collimation of the light-emitting diode. Each light-emitting unit 301 includes one or more groups of photonic crystal structures and one or more microlenses 90, which can improve the luminous efficiency of the light-emitting unit 301, and improve the light utilization rate and collimation.

[0066] Optional, Figure 7-Figure 9 is a schematic diagram of the structure of a photonic crystal provided in Example 1 of the present invention, with reference to Figure 3 , Figure 7-Figure 9 The first photonic crystal structure 81 and the second photonic crystal structure 82 include a plurality of nanorods 03 arranged at intervals; the shape of the nanorods 03 includes at least one of a cylinder, a truncated cone and a cone; Figure 10-12 A schematic diagram of the arrangement of a photonic crystal provided in the first embodiment of the invention, referring to Figure 10-12 The arrangement of the plurality of nanorods 03 includes one of a matrix arrangement, a staggered arrangement and a triangular arrangement.

[0067] in, Figure 7 The shape of the nanopillar 03 is cylindrical. Figure 8 The nanopillar 03 in the shape of a truncated cone, Fig. 9 The shape of the nanorod 03 is a cone. Different shapes of the nanorod 03 will affect the photonic band gap and optical properties of the photonic crystal structure. The shape of the nanorod 03 can be a sphere or a prism according to the needs. Fig.10 The arrangement of the multiple nano-pillars 03 is a matrix arrangement. Fig.11 The arrangement of the multiple nano-pillars 03 is staggered. Fig.12The arrangement of the multiple nanorods 03 is a triangular arrangement; the matrix arrangement, the staggered arrangement and the triangular arrangement are all regular arrangements, and the regular arrangement can form an obvious photonic band gap and improve the light utilization rate.

[0068] Optional, reference Figure 7-Figure 9 , the distance A between adjacent nanocolumns 03 is 200nm-700nm; the height B of the nanocolumns along the direction of the substrate pointing to the light-emitting unit layer is 150nm-1000nm; the angle C between the side wall of the nanocolumn 03 and the first surface of the nanocolumn 03 is 60°-90°, and the first surface of the nanocolumn 03 is the surface of the nanocolumn 03 on the side adjacent to the substrate 10.

[0069] The distance A between adjacent nanocolumns 03 is 200nm-700nm; the height B of the nanocolumns is 150nm-1000nm; and the angle C between the sidewall of the nanocolumn 03 and the first surface of the nanocolumn 03 is 60°-90°, which can improve light utilization and collimation.

[0070] Optional, reference Figure 1-Figure 5 The light-emitting diode structure also includes: a transparent conductive layer 50, a plurality of bonding layers 20 and a plurality of first insulating layers 40; the bonding layer 20 is located on a side of the light-emitting unit 301 adjacent to the substrate 10, and each bonding layer 20 corresponds to a light-emitting unit 301; the light-emitting unit 301 covers part of the bonding layer 20.

[0071] The first insulating layer 40 is located on the side of the light-emitting unit 301 away from the substrate 10, and the first insulating layer 40 includes a through hole 41; each first insulating layer 40 covers the side wall of the light-emitting unit 301, the side wall of the bonding layer 20 and the bonding layer 20 not covered by the light-emitting unit 301; when the second semiconductor layer 33 includes the first photonic crystal structure 81, the through hole 41 penetrates from the surface of the first insulating layer 40 away from the substrate 10 to the central area 01 of the second sub-area 332; when the second semiconductor layer 33 does not include the first photonic crystal structure 81, the through hole 41 penetrates from the surface of the first insulating layer 40 away from the substrate 10 to the second semiconductor layer 33.

[0072] The transparent conductive layer 50 is located on the side of the first insulating layer 40 away from the substrate 10 ; the transparent conductive layer 50 contacts the second semiconductor layer 33 through the through hole 41 ; the transparent conductive layer 50 covers the through hole 41 , the first insulating layer 40 and the substrate 10 not covered by the first insulating layer 40 .

[0073] Among them, the bonding layer 20 can be a metal bonding layer, and the metal bonding layer can include a first adhesion layer, a bonding metal, a barrier layer, a second adhesion layer and an ohmic contact layer that are stacked; the first adhesion layer can increase the adhesion with the substrate 10, and the second adhesion layer can increase the adhesion between the ohmic contact layer and the barrier layer. When the bonding metal is bonded to the substrate 10, the barrier layer can block the metal ions from diffusing into the ohmic contact layer, affecting the device performance. The metal bonding material can include gold-gold (Au-Au) bonding, copper-copper (Cu-Cu) bonding, gold-tin (Au-Sn) bonding or gold-indium (Au-In) bonding and other methods.

[0074] The first insulating layer 40 is used to protect all the light-emitting units 301. The first insulating layer is a transparent insulating passivation layer. The material of the first insulating layer 40 includes a transparent inorganic or plastic (organic) material; in some embodiments, the inorganic material includes silicon oxide, titanium oxide, silicon nitride, silicon carbide, aluminum oxide, phosphorus silicon glass (PSG), or any combination thereof. In some embodiments, the plastic material includes a polymer such as SU-8, benzocyclobutene (BCB), or a transparent plastic (resin) including spin-on glass (SOG), or any combination thereof. If the second semiconductor layer 33 includes a first photonic crystal structure 81, the material of the first photonic crystal structure 81 and the material of the first insulating layer 40 are alternately arranged, so that the light utilization rate of the first photonic crystal structure 81 is higher and the collimation is better.

[0075] The transparent conductive layer 50 is used to electrically connect the second semiconductor layers 33 of all the light-emitting units 301 , so that the second semiconductor layers 33 have the same electrical signal; the material of the transparent conductive layer 50 may be ITO material.

[0076] Optional, reference Figure 1-Figure 3 The light-emitting diode structure also includes: a second insulating layer 70 and a plurality of isolation layers 60; the isolation layer 60 is located on a side of the transparent conductive layer 50 away from the substrate 10, the isolation layer 60 covers a portion of the transparent conductive layer 50, and an isolation layer 60 is arranged between adjacent light-emitting units 301; the second insulating layer 70 is located on a side of the isolation layer 60 away from the substrate 10, the second insulating layer 70 covers a plurality of isolation layers 60 and the transparent conductive layer 50 not covered by the isolation layer 60.

[0077] Among them, the isolation layer 60 is a metal strip, and the isolation layer 60 can be used for current expansion and pixel isolation and segmentation. The material of the second insulating layer 70 is the same as that of the second photonic crystal structure 82. Since the light-emitting units 301 are arranged in a rectangular array, the thickness of the second insulating layer 70 needs to be set thicker, and the second insulating layer 70 needs to be flattened to improve the performance of the device. The material of the second insulating layer 70 includes a transparent inorganic or plastic (organic) material, which is used as a passivation layer and flattening material for the light-emitting unit. In some embodiments, the inorganic material includes silicon oxide, titanium oxide, silicon nitride, silicon carbide, aluminum oxide, phosphorus silicon glass (PSG), or any combination of the above. In some embodiments, the plastic material includes a polymer such as SU-8, benzocyclobutene (BCB), or a transparent plastic (resin) including spin-on glass (SOG), or any combination of the above. The second photonic crystal structure 82 is the same as the material of the second insulating layer 70, and the photonic crystal structure is formed by etching using electron beam exposure (EBL) and plasma etching (ICP).

[0078] Embodiment 2

[0079] The embodiment of the present invention provides a method for preparing a light emitting diode structure based on the above embodiment. Fig.13 is a flow chart of a method for preparing a light emitting diode structure provided in the second embodiment of the present invention, with reference to Fig.13 , the preparation method comprises:

[0080] S110, forming a substrate.

[0081] The substrate includes a plurality of driving units, each driving unit is provided with a contact point, and the contact points of the driving units are provided in a one-to-one correspondence with the light-emitting units, so that each light-emitting unit can be independently controlled.

[0082] S120, forming a light-emitting unit layer on one side of the substrate; the light-emitting unit layer includes a plurality of light-emitting units arranged at intervals; each light-emitting unit includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer arranged in a stacked manner, and the second semiconductor layer is located on a side of the first semiconductor layer away from the substrate.

[0083] Among them, the light-emitting unit layer is formed first, and the substrate and the light-emitting unit layer can be bonded together through a bonding process, and then the excess material and bonding metal material are removed through micro-nano processing, mainly photolithography, etching, and deposition, to form the final structure of the light-emitting unit layer.

[0084] S130, forming a plurality of second photonic crystal structures on a side of the light emitting unit layer away from the substrate; the second photonic crystal structures and the light emitting units are arranged in one-to-one correspondence, and the vertical projection of the second photonic crystal structure on the substrate covers the vertical projection of the light emitting unit on the substrate.

[0085] Wherein, a plurality of second photonic crystal structures are formed on a side of the light emitting unit layer away from the substrate by using electron beam exposure (EBL) and plasma etching (ICP) etching.

[0086] The following is a specific process of the method for preparing a light emitting diode structure according to the technical solution of the embodiment of the present invention: Figure 14-Figure 20 Schematic diagram of an intermediate structure of a light emitting diode structure provided by the second embodiment of the present invention, including:

[0087] S210, forming a substrate.

[0088] Among them, reference Fig.15 The substrate includes a plurality of driving units, each driving unit is provided with a contact point 11, and the contact points 11 of the driving units are provided in a one-to-one correspondence with the light-emitting units, so that each light-emitting unit can be independently controlled.

[0089] S220, forming a whole light-emitting unit layer.

[0090] S230, bonding the entire light-emitting unit layer and the substrate through the entire bonding layer.

[0091] Among them, reference Fig.14 The entire bonding layer 20 covers the substrate 10 , and the entire light-emitting unit layer 30 covers the entire bonding layer 20 .

[0092] S240, etching the entire light-emitting unit layer and the entire bonding layer to form a light-emitting unit layer and multiple bonding layers; the light-emitting unit layer includes multiple light-emitting units arranged at intervals; each light-emitting unit includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer arranged in a stacked manner, and the second semiconductor layer is located on a side of the first semiconductor layer away from the substrate.

[0093] Among them, reference Fig.15 First, the light-emitting unit layer is patterned and etched to form a plurality of light-emitting units 301, and then a plurality of bonding layers 20 are formed by photolithography. Along the direction parallel to the substrate 10, the size of each light-emitting unit 301 is smaller than the size of each bonding layer 20. When the entire bonding layer 20 is etched, the photoresist in the photolithography can protect each light-emitting unit 301, and prevent metal ions from entering the light-emitting unit 301 during etching of the bonding layer 20, causing a short circuit of the device, or damaging the side wall of the light-emitting unit 301 when etching the bonding layer 20.

[0094] The bonding layer 20 may be a metal bonding layer, which may include a first adhesion layer, a bonding metal, a barrier layer, a second adhesion layer and an ohmic contact layer that are stacked; the first adhesion layer may increase the adhesion to the substrate 10, and the second adhesion layer may increase the adhesion between the ohmic contact layer and the barrier layer. When the bonding metal is bonded to the substrate 10, the barrier layer may block the diffusion of metal ions to the ohmic contact layer, thereby affecting the device performance. The metal bonding material may include gold-gold (Au-Au) bonding, copper-copper (Cu-Cu) bonding, gold-tin (Au-Sn) bonding or gold-indium (Au-In) bonding and other methods.

[0095] S250, forming a plurality of first insulating layers on a side of the light-emitting unit away from the substrate; the first insulating layers include through holes; each first insulating layer covers the side wall of the light-emitting unit, the side wall of the bonding layer and the bonding layer not covered by the light-emitting unit; the through holes extend from the surface of the first insulating layer away from the substrate to the second semiconductor layer.

[0096] Among them, reference Fig.16 First, a whole first insulating layer 40 is deposited, and then a plurality of first insulating layers 40 having through holes 41 are formed by photolithography and etching.

[0097] S260, forming a transparent conductive layer on a side of the first insulating layer away from the substrate; wherein the transparent conductive layer contacts the second semiconductor layer through the through hole; and the transparent conductive layer covers the through hole, the first insulating layer and the substrate not covered by the first insulating layer.

[0098] S270, forming a plurality of isolation layers on one side of the transparent conductive layer source substrate; wherein the isolation layer covers a portion of the transparent conductive layer, and an isolation layer is disposed between adjacent light-emitting units.

[0099] S280, forming a second insulating layer on a side of the isolation layer away from the substrate; the second insulating layer covers the plurality of isolation layers and the transparent conductive layer not covered by the isolation layer.

[0100] S290, forming a plurality of second photonic crystal structures on a side of the second insulating layer away from the substrate; the second photonic crystal structures and the light-emitting units are arranged in one-to-one correspondence, and the vertical projection of the second photonic crystal structure on the substrate covers the vertical projection of the light-emitting unit on the substrate.

[0101] Among them, reference Fig.17 The second photonic crystal structure 82 is formed by etching the surface of the second insulating layer 70 away from the substrate 10 by electron beam exposure (EBL) and plasma etching (ICP).

[0102] S300, Reference Fig.18 A photoresist 91 is formed on a side of the second photonic crystal structure 82 away from the substrate 10 .

[0103] S310, Reference Fig.19 , a mask pattern 92 is formed on a side of the photoresist 91 away from the substrate 10 .

[0104] The mask pattern 92 may be formed by mask patterning.

[0105] S320, reference Fig.19 and Fig. 20 , a thermal reflow process is performed on the mask pattern 92 to form a curved mask pattern 92 .

[0106] Among them, reference Fig. 20 ,The thermal reflow process is carried out at a high temperature, which is the temperature at which the mask pattern can be melted into a curved surface.

[0107] S330, Reference Figure 2 , the photoresist 91 is etched through the curved mask pattern to form a plurality of microlenses 90. The refractive index of the material of the microlens 90 is greater than the refractive index of the material of the second photonic crystal structure 82; each light-emitting unit 301 corresponds to at least one microlens 90; the vertical projection of the microlens 90 on the substrate 10 covers the vertical projection of the second photonic crystal structure 82 on the substrate 10.

[0108] The number of microlenses on a single light-emitting unit is one or more, and the shape is generally hemispherical or truncated cone. In some embodiments, the microlenses composed of inorganic or organic materials are formed by mask patterning, photolithography, and then etching. In some embodiments, the microlenses composed of organic materials are formed by mask patterning, photolithography, and then performing a thermal reflow process at high temperature and etching.

[0109] In the method for preparing the light-emitting diode structure provided by the technical solution of the embodiment of the present invention, the second photonic crystal structure is used to suppress the lateral propagation of light emitted by the light-emitting unit, so that the light emitted by the light-emitting unit can only propagate along the direction of the light-emitting surface, thereby improving light utilization and collimation.

[0110] Embodiment 3

[0111] The difference between the third embodiment of the present invention and the second embodiment is that there is no need to form the second photonic crystal structure, and the first photonic crystal structure is formed on the surface of the second semiconductor layer away from the substrate.

[0112] An embodiment of the present invention provides a method for preparing a light emitting diode structure based on the above embodiment. Fig.21 is a flow chart of a method for preparing a light emitting diode structure provided in Example 3 of the present invention, with reference to Fig.21 , the preparation method comprises:

[0113] S410, forming a substrate.

[0114] Among them, S410 is the same as S110 and has the same beneficial effects.

[0115] S420. Form a light-emitting unit layer on one side of the substrate; the light-emitting unit layer includes a plurality of light-emitting units arranged at intervals; each light-emitting unit includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer which are stacked, and the second semiconductor layer is located on a side of the first semiconductor layer away from the substrate; the second semiconductor layer includes a first sub-region and a second sub-region, and the second sub-region is located on a side of the first sub-region away from the substrate, and the second sub-region also includes a central region and an edge region, the edge region surrounds the central region, and the edge region includes a first photonic crystal structure, and the first photonic crystal structure and the light-emitting layer are arranged in a one-to-one correspondence.

[0116] Among them, the light-emitting unit layer is formed first, and the substrate and the light-emitting unit layer can be bonded together through a bonding process, and then the excess material and bonding metal material are removed through micro-nano processing, mainly photolithography, etching, and deposition, to form the final structure of the light-emitting unit layer.

[0117] The following is a specific process of the method for preparing a light emitting diode structure according to the technical solution of the embodiment of the present invention: Fig. 22 Schematic diagram of an intermediate structure of a light-emitting diode structure provided by Embodiment 3 of the present invention, the preparation method includes:

[0118] S510, forming a substrate.

[0119] S520, forming a whole light-emitting unit layer.

[0120] S530, bonding the entire light-emitting unit layer and the substrate through the entire bonding layer;

[0121] S540, etching the entire light-emitting unit layer and the entire bonding layer to form a light-emitting unit layer and multiple bonding layers; the light-emitting unit layer includes multiple light-emitting units arranged at intervals; each light-emitting unit includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer arranged in a stacked manner, and the second semiconductor layer is located on a side of the first semiconductor layer away from the substrate; the second semiconductor layer includes a first sub-region and a second sub-region, and the second sub-region is located on a side of the first sub-region away from the substrate, and the second sub-region also includes a central region and an edge region, and the edge region surrounds the central region.

[0122] Among them, S510-S540 and S210-S240 have the same beneficial effects.

[0123] S550, etching the edge region of the second sub-region of the second semiconductor layer to form a first photonic crystal structure; wherein the first photonic crystal structure and the light-emitting layer are arranged in a one-to-one correspondence.

[0124] Among them, reference Fig. 22, etching the surface of the second sub-region of the edge region away from the substrate to form a first photonic crystal structure, and finally forming a light-emitting unit 301 having the first photonic crystal structure.

[0125] S560, forming a plurality of first insulating layers on a side of the light-emitting unit away from the substrate; the first insulating layers include through holes; each first insulating layer covers the side wall of the light-emitting unit, the side wall of the bonding layer and the bonding layer not covered by the light-emitting unit; the through holes extend from the surface of the first insulating layer away from the substrate to the central area of ​​the second sub-area.

[0126] The through holes may be arranged in a uniform width in the central region to improve the conductivity of the subsequent transparent conductive layer. The entire first insulating layer may be deposited first, and then a plurality of first insulating layers with through holes may be formed by photolithography.

[0127] S570, forming a transparent conductive layer on a side of the first insulating layer away from the substrate; wherein the transparent conductive layer contacts the second semiconductor layer through the through hole; and the transparent conductive layer covers the through hole, the first insulating layer and the substrate not covered by the first insulating layer.

[0128] S570, forming a plurality of isolation layers on one side of the transparent conductive layer source substrate; wherein the isolation layer covers a portion of the transparent conductive layer, and an isolation layer is disposed between adjacent light-emitting units.

[0129] S590, forming a second insulating layer on a side of the isolation layer away from the substrate; the second insulating layer covers the plurality of isolation layers and the transparent conductive layer not covered by the isolation layer.

[0130] S600 , forming a photoresist on a side of the second insulating layer away from the substrate.

[0131] S610, forming a mask pattern on a side of the photoresist away from the substrate.

[0132] S620 , performing a thermal reflow process on the mask pattern to form a curved mask pattern.

[0133] S630 , etching the photoresist through the curved mask pattern to form a plurality of micro lenses.

[0134] Among them, S570-S590 are the same as S260-S280, S600-S630 are the same as S300-S330, and have the same beneficial effects.

[0135] Embodiment 4

[0136] The difference between the fourth embodiment of the present invention and the third and second embodiments is that the fourth embodiment of the present invention forms both the second photonic crystal structure and the first photonic crystal structure.

[0137] The embodiment of the present invention provides a method for preparing a light emitting diode structure based on the above embodiment. Fig.23 is a flow chart of a method for preparing a light emitting diode structure provided in Example 4 of the present invention, with reference to Fig.23 , the preparation method comprises:

[0138] S710, forming a substrate;

[0139] S720, forming a light-emitting unit layer on one side of the substrate; the light-emitting unit layer includes a plurality of light-emitting units arranged at intervals; each light-emitting unit includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer arranged in a stacked manner, the second semiconductor layer being located on a side of the first semiconductor layer away from the substrate; the second semiconductor layer includes a first sub-region and a second sub-region, the second sub-region being located on a side of the first sub-region away from the substrate, the second sub-region further including a central region and an edge region, the edge region surrounding the central region, the edge region including a first photonic crystal structure, the first photonic crystal structure and the light-emitting layer being arranged in a one-to-one correspondence;

[0140] S730, forming a plurality of second photonic crystal structures on a side of the light emitting unit layer away from the substrate; the second photonic crystal structures and the light emitting units are arranged in one-to-one correspondence, and the vertical projection of the second photonic crystal structure on the substrate covers the vertical projection of the light emitting unit on the substrate.

[0141] The following is a specific process of the method for preparing a light-emitting diode structure according to the technical solution of the embodiment of the present invention. The preparation method comprises:

[0142] S810, forming a substrate.

[0143] S820, forming a whole light-emitting unit layer.

[0144] S830, bonding the entire light-emitting unit layer and the substrate through the entire bonding layer;

[0145] S840, etching the entire light-emitting unit layer and the entire bonding layer to form a light-emitting unit layer and multiple bonding layers; the light-emitting unit layer includes multiple light-emitting units arranged at intervals; each light-emitting unit includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer arranged in a stacked manner, and the second semiconductor layer is located on a side of the first semiconductor layer away from the substrate; the second semiconductor layer includes a first sub-region and a second sub-region, and the second sub-region is located on a side of the first sub-region away from the substrate, and the second sub-region also includes a central region and an edge region, and the edge region surrounds the central region.

[0146] S850, etching the edge region of the second sub-region of the second semiconductor layer to form a first photonic crystal structure; wherein the first photonic crystal structure and the light-emitting layer are arranged in a one-to-one correspondence.

[0147] S860. Form multiple first insulating layers on the side of the light-emitting unit away from the substrate; the first insulating layers include through holes; each first insulating layer covers the side wall of the light-emitting unit, the side wall of the bonding layer and the bonding layer not covered by the light-emitting unit; the through holes extend from the surface of the first insulating layer away from the substrate to the central area of ​​the second sub-area.

[0148] S870, forming a transparent conductive layer on a side of the first insulating layer away from the substrate; wherein the transparent conductive layer contacts the second semiconductor layer through the through hole; and the transparent conductive layer covers the through hole, the first insulating layer and the substrate not covered by the first insulating layer.

[0149] S580, forming a plurality of isolation layers on one side of the transparent conductive layer source substrate; wherein the isolation layer covers a portion of the transparent conductive layer, and an isolation layer is disposed between adjacent light-emitting units.

[0150] S890, forming a second insulating layer on a side of the isolation layer away from the substrate; the second insulating layer covers the plurality of isolation layers and the transparent conductive layer not covered by the isolation layer.

[0151] Among them, S810-S890 are the same as S510-S590 and have the same beneficial effects.

[0152] S900, forming a plurality of second photonic crystal structures on a side of the second insulating layer away from the substrate; the second photonic crystal structures and the light-emitting units are arranged in one-to-one correspondence, and the vertical projection of the second photonic crystal structure on the substrate covers the vertical projection of the light-emitting unit on the substrate.

[0153] S910 , forming a photoresist on a side of the second photonic crystal structure away from the substrate.

[0154] S920, forming a mask pattern on a side of the photoresist away from the substrate.

[0155] S930 , performing a thermal reflow process on the mask pattern to form a curved mask pattern.

[0156] S940, etching the photoresist through the curved mask pattern to form a plurality of micro lenses.

[0157] Among them, S900-S940 are the same as S290-S330 and have the same beneficial effects.

[0158] The method for preparing the light-emitting diode structure provided by any embodiment of the present invention has the same beneficial effects as the light-emitting diode structure described in any embodiment of the present invention.

[0159] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0160] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A light emitting diode structure, characterized in that: include: A light-emitting unit layer, the light-emitting unit layer is located on one side of the substrate; the light-emitting unit layer includes a plurality of light-emitting units arranged at intervals; Each of the light-emitting units comprises a first semiconductor layer, a light-emitting layer and a second semiconductor layer which are stacked, and the second semiconductor layer is located on a side of the first semiconductor layer away from the substrate; a plurality of second photonic crystal structures, wherein the second photonic crystal structures are located on a side of the light-emitting unit layer away from the substrate, the second photonic crystal structures and the light-emitting units are arranged in a one-to-one correspondence, and the vertical projection of the second photonic crystal structure on the substrate covers the vertical projection of the light-emitting unit on the substrate; The light emitting diode structure further includes: a plurality of micro lenses, the micro lenses being located on a side of the second photonic crystal structure away from the substrate; the refractive index of the material of the micro lenses being greater than the refractive index of the material of the second photonic crystal structure; The material of the second photonic crystal structure and the material of the microlens are arranged alternately.

2. The light emitting diode structure according to claim 1, characterized in that: The second semiconductor layer includes a first sub-region and a second sub-region, the second sub-region is located on a side of the first sub-region away from the substrate, the second sub-region also includes a central region and an edge region, the edge region surrounds the central region, the edge region includes a first photonic crystal structure, and the first photonic crystal structure and the light-emitting layer are arranged in a one-to-one correspondence.

3. The light emitting diode structure according to claim 1, characterized in that: Each of the light-emitting units corresponds to at least one microlens; a vertical projection of the microlens on the substrate covers a vertical projection of the second photonic crystal structure on the substrate.

4. The light emitting diode structure according to claim 2, characterized in that: The first photonic crystal structure and the second photonic crystal structure include a plurality of nanocolumns arranged at intervals; the shape of the nanocolumns includes at least one of a cylinder, a truncated cone and a cone; The arrangement of the plurality of nanorods includes one of a matrix arrangement, a staggered arrangement and a triangular arrangement.

5. The light emitting diode structure according to claim 4, characterized in that: The distance between adjacent nanopillars is 200nm-700nm; Along the direction from the substrate to the light-emitting unit layer, the height of the nanocolumns is 150nm-1000nm; The angle between the sidewall of the nanocolumn and the first surface of the nanocolumn is 60°-90°, and the first surface of the nanocolumn is the surface of the nanocolumn adjacent to the substrate.

6. The light emitting diode structure according to claim 2, characterized in that: Also includes: A transparent conductive layer, a plurality of bonding layers and a plurality of first insulating layers; The bonding layer is located on a side of the light-emitting unit adjacent to the substrate, and each bonding layer corresponds to a light-emitting unit; the light-emitting unit covers a portion of the bonding layer; The first insulating layer is located on a side of the light-emitting unit away from the substrate, and the first insulating layer includes a through hole; each of the first insulating layers covers the side wall of the light-emitting unit, the side wall of the bonding layer, and the bonding layer not covered by the light-emitting unit; when the second semiconductor layer includes a first photonic crystal structure, the through hole penetrates from the surface of the first insulating layer away from the substrate to the central area of ​​the second sub-area; when the second semiconductor layer does not include the first photonic crystal structure, the through hole penetrates from the surface of the first insulating layer away from the substrate to the second semiconductor layer; The transparent conductive layer is located on a side of the first insulating layer away from the substrate; the transparent conductive layer contacts the second semiconductor layer through the through hole; the transparent conductive layer covers the through hole, the first insulating layer and the substrate not covered by the first insulating layer.

7. The light emitting diode structure according to claim 6, characterized in that: Also includes: a second insulating layer and a plurality of isolation layers; The isolation layer is located on a side of the transparent conductive layer away from the substrate, the isolation layer covers a portion of the transparent conductive layer, and one isolation layer is disposed between adjacent light-emitting units; The second insulating layer is located at a side of the isolation layer away from the substrate, and the second insulating layer covers a plurality of isolation layers and the transparent conductive layer not covered by the isolation layer.

8. A method for preparing a light emitting diode structure, characterized in that: include: forming a substrate; A light-emitting unit layer is formed on one side of the substrate; the light-emitting unit layer includes a plurality of light-emitting units arranged at intervals; Each of the light-emitting units comprises a first semiconductor layer, a light-emitting layer and a second semiconductor layer which are stacked, and the second semiconductor layer is located on a side of the first semiconductor layer away from the substrate; A plurality of second photonic crystal structures are formed on a side of the light-emitting unit layer away from the substrate; the second photonic crystal structures are arranged in a one-to-one correspondence with the light-emitting units, and a vertical projection of the second photonic crystal structure on the substrate covers a vertical projection of the light-emitting unit on the substrate; After forming a plurality of second photonic crystal structures on a side of the light emitting unit layer away from the substrate, the method further includes: A plurality of micro lenses are formed; the refractive index of the material of the micro lenses is greater than the refractive index of the material of the second photonic crystal structure; the material of the second photonic crystal structure and the material of the micro lenses are arranged alternately.

9. A method for preparing a light emitting diode structure, characterized in that: include: forming a substrate; A light-emitting unit layer is formed on one side of the substrate; the light-emitting unit layer includes a plurality of light-emitting units arranged at intervals; Each of the light-emitting units includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer which are stacked, wherein the second semiconductor layer is located on a side of the first semiconductor layer away from the substrate; the second semiconductor layer includes a first sub-region and a second sub-region, wherein the second sub-region is located on a side of the first sub-region away from the substrate, and the second sub-region further includes a central region and an edge region, wherein the edge region surrounds the central region, and the edge region includes a first photonic crystal structure, and the first photonic crystal structure and the light-emitting layer are arranged in a one-to-one correspondence; A plurality of second photonic crystal structures are formed on a side of the light-emitting unit layer away from the substrate; the second photonic crystal structures are arranged in a one-to-one correspondence with the light-emitting units, and a vertical projection of the second photonic crystal structure on the substrate covers a vertical projection of the light-emitting unit on the substrate; After forming a plurality of second photonic crystal structures on a side of the light emitting unit layer away from the substrate, the method further includes: forming a plurality of micro lenses on a side of the second photonic crystal structure away from the substrate; The refractive index of the material of the microlens is greater than the refractive index of the material of the second photonic crystal structure; Each of the light-emitting units corresponds to at least one microlens; a vertical projection of the microlens on the substrate covers a vertical projection of the second photonic crystal structure on the substrate; and materials of the second photonic crystal structure and materials of the microlenses are arranged alternately.

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