Micro light emitting diode and manufacturing method thereof

Abstract

The present invention relates to the field of light-emitting diodes, which include a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence, wherein the first semiconductor layer and the second semiconductor layer are semiconductor layers of different types, the active layer includes a first quantum well layer and a second quantum well layer stacked in sequence, a nano-ring structure is formed on the second quantum well layer and the second semiconductor layer, the first quantum well layer emits light of a first color, the second quantum well layer and the part corresponding to the side wall of the nano-ring emit light of a second color, the first color is different from the second color, the first semiconductor layer is electrically connected to a first electrode, and the second semiconductor layer is electrically connected to a second electrode. The present invention also includes a method for manufacturing the micro-light-emitting diode, wherein nano-silicon dioxide particles are used as a light mask to make the nano-ring, which releases the original quantum well stress and reduces the quantum confined Stark effect to produce blue light.

Description

Technical Field

[0001] The present invention relates to the technical field of LED display device manufacturing, and in particular to a micro light emitting diode and a manufacturing method thereof. Background Art

[0002] A general light-emitting diode (LED) chip includes a substrate and an epitaxial layer, which is about 100 to 500 μm thick and 100 to 1000 μm in size. The ongoing research on micro-LED display panels is to lift off the epitaxial layer of the LED surface, which is about 4 to 5 μm thick, using physical or chemical mechanisms, and then transplant it to the circuit substrate. Micro-LED displays combine the two major technical features of thin film transistor liquid crystal display (TFT-LCD) and LED. The development of materials, processes, and equipment is relatively mature. The product specifications are much higher than the current TFT-LCD or organic light-emitting diode (OLED). The application field is more extensive, including flexible and transparent displays. It is a highly feasible next-generation flat panel display technology.

[0003] Currently, there are two methods for applying micro LED chips in full-color AR micro displays and mobile / large displays. One is to use the three primary colors (Red Green Blue, RGB) of micro LEDs for natural color mixing; the other is quantum dots (QDs) + blue micro LED chips. If RGB micro LED chips are used for natural color mixing, the disadvantage is that the red color is GaAs material, and the green and blue colors are InGaN materials, which will cause difficulties in display board circuit design. If quantum dots + blue micro LED chips are used, the green light quantum dot color conversion efficiency is not high, resulting in low full color efficiency. Summary of the invention

[0004] Based on the above problems, the present invention designs a micro light emitting diode that can emit white light by mixing three colors. The specific structure is as follows:

[0005] A micro-light-emitting diode comprises a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence, wherein the first semiconductor layer and the second semiconductor layer are semiconductor layers of different types, the active layer comprises a first quantum well layer and a second quantum well layer stacked in sequence, a nano-ring structure is formed on the second quantum well layer and the second semiconductor layer, the first quantum well layer emits light of a first color, the second quantum well layer emits light of a second color at a position corresponding to a side wall of the nano-ring, the first color is different from the second color, the first semiconductor layer is electrically connected to a first electrode, and the second semiconductor layer is electrically connected to a second electrode.

[0006] Furthermore, the first semiconductor layer is an N-type semiconductor layer, which includes a low-temperature GaN layer, an undoped GaN layer and an N-type GaN layer stacked in sequence, and the second semiconductor layer is a P-type semiconductor layer.

[0007] Furthermore, the nano-ring is filled with a color conversion material, and the color conversion material converts the light of the first color emitted by the first quantum well into light of a third color, and the first color, the second color and the third color are all different.

[0008] Furthermore, the first quantum well layer and the second quantum well layer are green light quantum well layers, and the materials of the first quantum well layer and the second quantum well layer include InGaN and GaN.

[0009] Furthermore, the structure of a pair of quantum wells is InGaN well layer / low-temperature GaN / high-temperature GaN stacked in sequence, the first quantum well layer includes 10 pairs of the green light quantum wells, and the second quantum well layer includes 10 pairs of the green light quantum wells.

[0010] Furthermore, a current diffusion layer is formed on the second semiconductor layer, the material of the current diffusion layer is ITO, and the second electrode is formed on a surface of the current diffusion layer away from the second semiconductor layer.

[0011] The present invention also includes a method for manufacturing a micro light emitting diode, which includes the following steps:

[0012] Providing a substrate, and sequentially forming a first semiconductor layer on the substrate, wherein the first semiconductor layer is a GaN semiconductor;

[0013] forming an active layer on the first semiconductor layer, wherein the active layer is a quantum well layer, the quantum well layer is formed by a plurality of pairs of quantum wells, and the quantum well layer emits light of a first color;

[0014] forming a second semiconductor layer on the quantum well layer, wherein the second semiconductor layer and the first semiconductor layer are semiconductors of different types;

[0015] etching the second semiconductor layer and a portion of the active layer to form a plurality of nanorings, wherein the sidewalls of the nanorings emit light of a second color, the second color being different from the second color;

[0016] forming a current diffusion layer on the nanoring;

[0017] A second electrode is formed on the current diffusion layer.

[0018] Furthermore, after the step of forming the second electrode on the current diffusion layer, the step also includes removing part of the current diffusion layer, the nanoring and the active layer to expose part of the first semiconductor layer, forming a first electrode on the exposed first semiconductor layer, the upper surface of the first electrode is flush with the upper surface of the second electrode, and then removing the substrate, transferring the remaining structure to a display panel, and bonding the first electrode and the second electrode to the electrodes on the display panel.

[0019] Furthermore, after the step of forming a plurality of nanorings and before the step of forming a current diffusion layer on the nanorings, a step is also included in which a color conversion material is formed in the nanorings, wherein the color conversion material converts light into light of a third color, and the third color is different from the first color and the second color.

[0020] Furthermore, after the step of forming the first electrode on the exposed first semiconductor layer, the method further includes the step of removing the substrate layer and forming a third electrode on the surface of the first semiconductor layer away from the active layer.

[0021] The beneficial effects of the present invention are:

[0022] The present application sets part of the green light quantum well as a nanoring structure, and fills the nanoring with red light quantum dots, so that the part of the quantum well structure that is not set as a nanoring can emit green light, and the nanoring part emits blue light due to the change in the emission wavelength due to the release of material stress, and the red light quantum dots emit red light, so that the quantum well structure spontaneously emits white light at the three-color mixing point; the present application uses a nanoring structure to slow down the problem of spontaneous built-in electric field generated due to different electron affinities, thereby causing the energy band bending in the quantum well to reduce the electron and hole recombination efficiency, thereby improving the electron and hole recombination efficiency; the structure of the present application is a micro LED chip with a size of 10 to 80 um, which will enable AR micro displays and mobile / large displays to have ultra-high resolution characteristics.

[0023] This application uses SiO2 nanospheres as a photomask, and uses yellow light lithography to make nanorings, which will release the original quantum well stress and reduce the quantum confined Stark effect (QCSE) to produce blue light. Red quantum dots are placed in the nanostructure by spraying, evenly covering the inside of the nanoring, and the color conversion efficiency is improved due to the surface area effect of the nanostructure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The micro light emitting diode of the present invention;

[0025] Figure 2 This is a planar schematic diagram of the nanoring on the first quantum well;

[0026] Figure 3 Another micro light emitting diode of the present invention;

[0027] Figure 4 A flow chart of a method for making a micro light emitting diode;

[0028] Figure 5 It is a schematic diagram of a structure in which a first semiconductor layer is formed on a substrate;

[0029] Figure 6 A schematic diagram of a structure in which an active layer and a second semiconductor layer are formed on a first semiconductor layer;

[0030] Figure 7 Schematic diagram of the structure of the nanoring;

[0031] Figure 8 A schematic diagram of the structure of setting the color conversion material in the nano ring;

[0032] Fig. 9 A schematic diagram of a structure for forming a current diffusion layer;

[0033] Fig.10 A schematic diagram of a structure for forming a second electrode;

[0034] Fig.11 A schematic diagram of a structure for forming a first electrode;

[0035] Fig.12 A schematic diagram of the structure of bonding a light emitting diode to a display panel.

[0036] Description of the numbers in the figure:

[0037] Substrate 10, first semiconductor layer 11, low-temperature GaN layer 111, undoped GaN layer 112, N-type GaN layer 113, active layer 12, first quantum well layer 121, second quantum well layer 122, second semiconductor layer 13, nanoring 14, first electrode 114, color conversion material 15, second electrode 16, current diffusion layer 17, display panel 20, third electrode 18. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. The described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0039] The terms "first", "second" and "third" in this application are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly naming the number of technical features indicated. Therefore, a feature defined as "first", "second" or "third" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0040] Example 1

[0041] like Figure 1 The micro light emitting diode described in the present invention is shown.

[0042] Specific structure such as Figure 1 As shown, it includes a first semiconductor layer 11 , an active layer 12 and a second semiconductor layer 13 .

[0043] The first semiconductor layer 11 is an N-type semiconductor, more preferably GaN, which is a new generation of energy materials and is widely used in light-emitting diodes.

[0044] The first semiconductor layer 11 includes a low-temperature GaN layer 111 , on which an undoped GaN layer 112 and an N-type GaN layer 113 are sequentially stacked.

[0045] The active layer 12 is a quantum well layer, and the active layer 12 is composed of multiple pairs of quantum wells. The active layer 12 includes a first quantum well layer 121 and a second quantum well layer 122. The quantum well layer in this embodiment is a green light quantum well layer, that is, it emits green light after being powered on.

[0046] In this embodiment, the structure of a pair of quantum wells is InGaN well layer / low temperature GaN / high temperature GaN stacked in sequence, and the first quantum well layer 121 is composed of 10 pairs of quantum wells. The thickness of the 10 pairs of quantum wells is better matched in application and manufacturing, and the difficulty of manufacturing is not increased under the premise of reasonably controlling the size of the micro-light-emitting diode. In other embodiments, the first quantum well layer 121 can also be formed by stacking other numbers of quantum wells, depending on the chip design.

[0047] A first electrode 114 is also formed on the first semiconductor layer 11 . The first electrode 114 is partially embedded in the first semiconductor layer 11 or located on the first semiconductor layer 11 and connected to the first semiconductor layer 11 .

[0048] A nano ring 14 is formed on the first quantum well layer 121, and the outer diameter R of the nano ring 14 is 10-2000 nm, more preferably 100-900 nm. The nano ring 14 of this size is easy to realize in terms of technology, and can well control the uniformity of the three-color mixed light emission.

[0049] like Figure 1 and Figure 2 As shown, in this embodiment, the nano ring 14 is formed on the first quantum well layer 121 in a hollow cylindrical shape. In other embodiments, the nano ring 14 can also be other three-dimensional shapes, as long as the hollow structure is satisfied, such as the cross section of the nano ring 14 can be in the shape of any polygon such as a square, a rectangle, or other closed loop. The nano ring structure can reduce the problem of spontaneous built-in electric field generated due to different electron affinities, thereby causing the energy band bending in the quantum well to reduce the recombination efficiency of electrons and holes, thereby improving the recombination efficiency of electrons and holes.

[0050] The sidewall of the nano-ring 14 includes a second quantum well layer 122 and a second semiconductor layer 13 . The second quantum well layer 122 is located between the first quantum well layer 121 and the second semiconductor layer 13 .

[0051] A color conversion material 15 is arranged in the nano ring 14, and the color conversion material 15 is a red quantum dot. The red quantum dot can convert the green light emitted by the first quantum well layer into red light. Filling the nano ring with red quantum dots can make the part of the quantum well structure that does not form the nano ring 14 emit green light, and the part of the second green light quantum well layer 121 on the nano ring 14 emits blue light due to the release of material stress. The red quantum dots emit red light, so that the quantum well structure spontaneously emits white light after the three colors are mixed.

[0052] A second electrode 16 is also formed on the second semiconductor layer 13. The second electrode 16 is an external electrode, and is preferably an ITO conductive film.

[0053] The structure of a pair of quantum wells is InGaN well layer / low temperature GaN / high temperature GaN stacked in sequence. In this embodiment, the first quantum well layer 121 and the second quantum well layer 122 each include 10 pairs of quantum wells. The thickness of the stack can be easily controlled in terms of process, and the luminous efficiency is high, and the thickness of the epitaxial layer will not be too large.

[0054] A current diffusion layer 17 is further formed on the nano-ring 14 and the first quantum well layer 121, and the current diffusion layer 17 completely covers the nano-ring 14 and the first quantum well layer 121. The material of the current diffusion layer 17 is a transparent oxide, and more preferably ITO.

[0055] At least one second electrode 16 is formed on the current diffusion layer 17. The upper surfaces of the first electrode 14 and the second electrode 16 are on the same level, so that they can be packaged in a flip chip packaging manner.

[0056] Example 2

[0057] This embodiment is another light emitting diode structure of a micro light emitting diode.

[0058] Specific structure such as Figure 3 As shown, it includes a first semiconductor layer 11 , an active layer 12 and a second semiconductor layer 13 .

[0059] The first semiconductor layer 11 is an N-type semiconductor, more preferably GaN, which is a new generation of energy materials and is widely used in light-emitting diodes.

[0060] The first semiconductor layer 11 includes a low-temperature GaN layer 111 , on which an undoped GaN layer 112 and an N-type GaN layer 113 are sequentially stacked.

[0061] The active layer 12 is a quantum well layer, and the active layer 12 is composed of multiple pairs of quantum wells. The active layer 12 includes a first quantum well layer 121 and a second quantum well layer 122. The quantum well layer in this embodiment is a green light quantum well layer, that is, it emits green light after being powered on.

[0062] In this embodiment, the structure of a pair of quantum wells is InGaN well layer / low temperature GaN / high temperature GaN stacked in sequence, and the first quantum well layer 121 is composed of 10 pairs of quantum wells. The thickness of the 10 pairs of quantum wells is better matched in application and manufacturing, and the difficulty of manufacturing is not increased under the premise of reasonably controlling the size of the micro-light-emitting diode. In other embodiments, the first quantum well layer 121 can also be formed by stacking other numbers of quantum wells, depending on the chip design.

[0063] A nano ring 14 is formed on the first quantum well layer 121, and the outer diameter R of the nano ring 14 is 10-2000 nm, more preferably 100-900 nm. The nano ring 14 of this size is easy to realize in terms of technology, and can well control the uniformity of the three-color mixed light emission.

[0064] like Figure 2 and Figure 3 As shown, in this embodiment, the nano ring 14 is formed on the first quantum well layer 121 in a hollow cylindrical shape. In other embodiments, the nano ring 14 can also be other three-dimensional shapes, as long as the hollow structure is satisfied, such as the cross section of the nano ring 14 can be in the shape of any polygon such as a square, a rectangle, or other closed loop. The nano ring structure can reduce the problem of spontaneous built-in electric field generated due to different electron affinities, thereby causing the energy band bending in the quantum well to reduce the recombination efficiency of electrons and holes, thereby improving the recombination efficiency of electrons and holes.

[0065] The sidewall of the nano-ring 14 includes a second quantum well layer 122 and a second semiconductor layer 13 . The second quantum well layer 122 is located between the first quantum well layer 121 and the second semiconductor layer 13 .

[0066] A color conversion material 15 is provided in the nano ring 14. In this embodiment, the color conversion material 15 is a red quantum dot, which can convert the green light emitted by the first quantum well layer 121 into red light. Filling the nano ring with red light quantum dots can make the part of the quantum well structure where the nano ring 14 is not formed emit green light, and the part of the second green light quantum well layer 121 on the nano ring 14 emits blue light due to the release of material stress, and the red quantum dots emit red light, so that the quantum well structure spontaneously emits white light after the three colors are mixed.

[0067] A second electrode 16 is also formed on the second semiconductor layer 13. The second electrode 16 is an external electrode, and is preferably an ITO conductive film.

[0068] A third electrode 18 is formed on the side of the first semiconductor layer 11 facing away from the active layer 12. The third electrode 18 is preferably made of an ITO thin film material. The specific method is to deposit an ITO material on the first semiconductor layer 11 to form a thin film, and then etch it to form the third electrode. ITO material is used as an electrode in light-emitting diodes and has excellent mechanical properties and conductivity.

[0069] The structure of a pair of quantum wells is InGaN well layer / low temperature GaN / high temperature GaN stacked in sequence. In this embodiment, the first quantum well layer 121 and the second quantum well layer 122 each include 10 pairs of quantum wells. The thickness of the stack can be easily controlled in terms of process, and the luminous efficiency is high, and the thickness of the epitaxial layer will not be too large.

[0070] A current diffusion layer 17 is further formed on the nano-ring 14 and the first quantum well layer 121, and the current diffusion layer 17 completely covers the nano-ring 14 and the first quantum well layer 121. The material of the current diffusion layer 17 is a transparent oxide, and more preferably ITO.

[0071] Example 3

[0072] like Figure 4 The following is a method for manufacturing a micro-LED according to the present application. The specific steps are as follows:

[0073] S10 provides a substrate 10 and forms a first semiconductor layer 11 on the substrate 10 .

[0074] like Figure 5 As shown, the first semiconductor layer 11 includes a low-temperature GaN layer 111, an undoped GaN layer 112 and an N-type GaN layer 113 which are stacked one by one, and the substrate 10 is a sapphire substrate.

[0075] S11 forms an active layer 12 and a second semiconductor layer 13 on the first semiconductor layer 11 .

[0076] like Figure 6 As shown, the active layer 12 is a quantum well layer, which is composed of a first quantum well layer 121 and a second quantum well layer 122, and a second semiconductor layer 13 is formed on the second quantum well layer. The first semiconductor layer 11 and the second semiconductor layer 13 are different types of semiconductors. In this embodiment, the first semiconductor layer 11 is an N-type semiconductor, and the second semiconductor layer is a P-type semiconductor. Specifically, the second semiconductor layer 13 is a P-type GaN layer.

[0077] The structure of a pair of quantum wells is InGaN well layer / low temperature GaN / high temperature GaN stacked in sequence, and the first quantum well layer 121 and the second quantum well layer 122 preferably include 10 pairs of green light quantum wells. The thickness of the first quantum well layer 121 and the second quantum well layer 122 set in this embodiment is conducive to controlling the difficulty of the process. If it is too thin, the process requirements will be higher and the light-emitting effect will be affected. However, if it is too thick, it will not be conducive to the thinness of the display panel.

[0078] S12 etches the second semiconductor layer 13 and the second quantum well layer 121 by a photolithography etching process to form a plurality of nano-ring structures 14, such as Figure 7 shown.

[0079] The specific method of the yellow light lithography process is to use nano-silicon dioxide particles to form a patterned mask on the second semiconductor layer 13, and then use dry etching to etch to form the nano ring 14. If the nano-silicon dioxide particles are not used and yellow light lithography is used, only the plane epitaxy will have stress and emit green light. After using SiO2 nanospheres and yellow light lithography to make the nano ring 14, the original quantum well stress will be released and the quantum confined Stark effect (Quantum Confined Stark Effect, QCSE) will be reduced to produce blue light.

[0080] S13 arranges the color conversion material 15 in the nano ring 14 .

[0081] like Figure 8 As shown, in this embodiment, the color conversion material 15 is red quantum dots, which are sprayed into the nano ring 14 by spraying. Filling the nano ring with red light quantum dots can make the part of the quantum well structure that does not form the nano ring 14 emit green light, and the second green light quantum well layer 121 on the nano ring 14 emits blue light due to the change of the emission wavelength due to the material stress release, and the red quantum dots convert the green light emitted by the first quantum well layer 122 into red light, so that the three-color mixing point of the quantum well structure spontaneously emits white light.

[0082] S14 forms a current diffusion layer 17 on the first quantum well layer 121 and the nano-ring 14 .

[0083] like Fig. 9 As shown, the current diffusion layer 17 is preferably a transparent oxide layer, more preferably an ITO film, formed by depositing an ITO material.

[0084] S15: forming at least one second electrode 16 on the current diffusion layer 17.

[0085] like Fig.10 The second electrode 16 is preferably an ITO film, which is formed by depositing an ITO material on the current diffusion layer 17 and then performing selective etching.

[0086] S16 removes a portion of the current diffusion layer 17 , the nano-rings 14 and the first quantum well layer 121 to expose a portion of the first semiconductor layer 11 , and forms a first electrode 114 on the exposed first semiconductor layer 11 .

[0087] Preferably, the upper surface of the first electrode 114 is flush with the upper surface of the second electrode 16. Fig.11 The upper surface of the first electrode 114 is flush with the upper surface of the second electrode 16, which is conducive to packaging the light emitting diode using a flip chip packaging method.

[0088] S17 removes the substrate 10 and transfers the obtained structure to a display panel 20 .

[0089] The first electrode 114 and the second electrode 16 are bonded to the electrodes on the display panel 30, such as Fig.12 shown.

[0090] In this embodiment, the color of the light emitted by the active layer 12 and the color of the color conversion material are only selected for illustration of this embodiment. In other structures, when other materials are used as quantum well layers, nano-rings and color conversion materials, it is only necessary to ensure that the colors emitted by the first quantum well layer 121, the nano-ring sidewalls and the color conversion material are different to realize the concept of the present invention.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0092] The basic principles of the present disclosure are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present disclosure are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present disclosure. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, and are not limitations. The above details do not limit the present disclosure to the necessity of adopting the above specific details to be implemented.

Claims

1. A micro light emitting diode, characterized in that: include: A first semiconductor layer, an active layer, and a second semiconductor layer are sequentially stacked, wherein the first semiconductor layer and the second semiconductor layer are semiconductor layers of different types, the active layer comprises a first quantum well layer and a second quantum well layer stacked in sequence, a plurality of nano-rings are formed on the first quantum well layer, the sidewalls of the nano-rings comprise a second quantum well layer and a second semiconductor layer which are ring-shaped and stacked, and the second quantum well layer is located between the first quantum well layer and the second semiconductor layer; the first quantum well layer emits light of a first color, the sidewalls of the nano-rings emit light of a second color at a position corresponding to the second quantum well layer, the first color is different from the second color, the first semiconductor layer is electrically connected to a first electrode, and the second semiconductor layer is electrically connected to a second electrode.

2. The micro light emitting diode according to claim 1, characterized in that: The first semiconductor layer is an N-type semiconductor layer, which includes a low-temperature GaN layer, an undoped GaN layer and an N-type GaN layer stacked in sequence, and the second semiconductor layer is a P-type semiconductor layer.

3. The micro light emitting diode according to claim 1, characterized in that: The nano ring is filled with a color conversion material, and the color conversion material converts the light of the first color emitted by the first quantum well into light of a third color, and the first color, the second color and the third color are all different.

4. The micro light emitting diode according to claim 1 or 3, characterized in that: The first quantum well layer and the second quantum well layer are green light quantum well layers, and the materials of the first quantum well layer and the second quantum well layer include InGaN and GaN.

5. The micro light emitting diode according to claim 4, characterized in that: The structure of a pair of quantum wells is InGaN well layer / low-temperature GaN / high-temperature GaN stacked in sequence, the first quantum well layer includes 10 pairs of the green light quantum wells, and the second quantum well layer includes 10 pairs of the green light quantum wells.

6. The micro light emitting diode according to claim 1, characterized in that: A current diffusion layer is formed on the second semiconductor layer. The material of the current diffusion layer is ITO. The second electrode is formed on a surface of the current diffusion layer away from the second semiconductor layer.

7. A method for manufacturing a micro light emitting diode, characterized in that: The following steps are included: Providing a substrate, and sequentially forming a first semiconductor layer on the substrate, wherein the first semiconductor layer is a GaN semiconductor; forming an active layer on the first semiconductor layer, wherein the active layer is a quantum well layer, the quantum well layer is formed by a plurality of pairs of quantum wells, and the quantum well layer emits light of a first color; forming a second semiconductor layer on the quantum well layer, wherein the second semiconductor layer and the first semiconductor layer are semiconductors of different types; Etching the second semiconductor layer and a portion of the active layer to form a plurality of nanorings, wherein the sidewalls of the nanorings emit light of a second color, the second color being different from the second color; forming a current diffusion layer on the nanoring; A second electrode is formed on the current diffusion layer.

8. The method for manufacturing a micro light emitting diode according to claim 7, characterized in that: After the step of forming the second electrode on the current diffusion layer, the method further includes removing part of the current diffusion layer, the nanoring and the active layer to expose part of the first semiconductor layer, forming a first electrode on the exposed first semiconductor layer, wherein the upper surface of the first electrode is flush with the upper surface of the second electrode, and then removing the substrate, transferring the remaining structure to a display panel, and bonding the first electrode and the second electrode to the electrodes on the display panel.

9. The method for manufacturing a micro light emitting diode according to claim 7, wherein: After the step of forming a plurality of nanorings and before the step of forming a current diffusion layer on the nanorings, the method further includes forming a color conversion material in the nanorings, wherein the color conversion material converts light into a third color of light, and the third color is different from the first color and the second color.

10. The method for manufacturing a micro light emitting diode according to claim 8, characterized in that: After the step of forming the first electrode on the exposed first semiconductor layer, the method further includes the step of removing the substrate layer and forming a third electrode on a surface of the first semiconductor layer away from the active layer.

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