Multi-dimensional mixed Micro / Nano LED array and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor optoelectronic device preparation, in particular to a multi-dimensional mixed Micro / Nano LED array and a preparation method thereof. The substrate comprises a substrate from bottom to top; a defective graphene film; the two-dimensional transition metal compound graphic array is positioned at a defect site of the defective graphene film; the co-metal electrode is located in the area, not covered by the two-dimensional transition metal compound pattern array, of the defective graphene film; the nitride Micro / Nano-LED array is only stacked on the two-dimensional transition metal compound pattern array; the metal top electrode is positioned on the upper surface of the nitride Micro / Nano-LED array; the photosensitive composite filling layer is located in a gap which is not covered by the nitride Micro / Nano-LED array, and the photosensitive composite filling layer and the top end of the array are kept at the same height. The method has the advantages that the device array size is controllable; the metal nanoparticles provide a scattering path for lateral propagation light; the luminous efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor optoelectronic device preparation, and particularly relates to a multi-dimensional hybrid Micro / Nano LED array and a preparation method thereof. BACKGROUND

[0002] Micro / Nano LED is a new type of light-emitting device based on micro-nano processing technology, and the size of a single device is usually less than 50 microns. Micro / Nano LED has unique advantages in high-resolution display, transparent display, and flexible / foldable display applications. Compared with Micro-LED, Nano-LED has a smaller size, usually less than 1 micron, which enables Nano-LED to be used to prepare a display screen with extremely high pixel density, and Nano-LED has an irreplaceable role in high-resolution application scenarios such as virtual reality / augmented reality near-eye imaging devices and micro projectors.

[0003] However, the processing of high-precision Nano-LED requires nanoscale precision, and relies on electron beam lithography or nanoimprint technology. The former has a contradiction between nanoscale precision and wafer-level manufacturing requirements, and the latter is limited by the geometric parameters of the nanoimprint template and has poor tunability. In addition, the uniformity and repeatability of the Nano-LED device array prepared by the existing process / technology are still difficult to guarantee, and there is performance fluctuation between the pixels. On the other hand, the sidewall bare area of the nanomaterial increases, and the high specific surface area causes the device to easily oxidize during operation, and then performance degradation or failure occurs. At the same time, due to the structure size of Nano-LED being close to or smaller than the wavelength of light, the light waveguide effect makes most of the light unable to move out (the light loss of nanowire LED is greater than 70%), and how to improve the light-emitting efficiency of Nano-LED is also a key problem.

[0004] Currently, the technology of laser processing SiO2 mask pattern array has been proposed and used for selective epitaxy of nitride Micro / Nano-LED device array. Generally, the epitaxial growth of the structure is realized only at the mask opening on the exposed sapphire substrate. Notably, the lateral epitaxial growth of the Micro / Nano-LED device needs to be inhibited to ensure the independence between the pixels. In addition, although the laser spot is relatively small and has high precision, the ablation of the thick SiO2 mask layer still requires high laser energy density, which can easily lead to rough edges of the SiO2 mask pattern opening, and the local high temperature will also cause thermal decomposition / damage of the substrate, which poses a challenge to the uniformity and stability of the Micro / Nano-LED device array. More importantly, the epitaxial Micro / Nano-LED relying on a dielectric substrate such as sapphire still needs dry etching or massive transfer to expose the n-type nitride doped layer at the epitaxial interface for metal electrode deposition and electrical injection in the subsequent device preparation process, which is technically difficult and prone to additional problems. SUMMARY

[0005] The present application provides a multi-dimensional hybrid Micro / Nano LED array and a preparation method thereof to solve the above problems.

[0006] The first object of the present application is to provide a multi-dimensional hybrid Micro / Nano LED array, which comprises, from bottom to top: a substrate; a defective graphene film on the upper surface of the substrate; a two-dimensional transition metal compound pattern array at the defect sites of the defective graphene film; a common metal electrode on the region of the defective graphene film not covered by the two-dimensional transition metal compound pattern array; a nitride Micro / Nano-LED array stacked only on the two-dimensional transition metal compound pattern array; a metal top electrode on the upper surface of the nitride Micro / Nano-LED array; a photosensitive composite filling layer in the gap region not covered by the nitride Micro / Nano-LED array, maintaining the same height as the top end of the nitride Micro / Nano-LED array.

[0007] Preferably, the defective graphene film is prepared by laser-induced formation of defect sites on the continuous double-layer graphene film on the substrate; The thickness of the double-layer graphene film is less than 1 nanometer; and the characteristic size of the defect sites is 200-500 nanometers.

[0008] Preferably, the two-dimensional transition metal compound pattern array has more than 3 layers and a thickness of less than 3 nanometers.

[0009] Preferably, the two-dimensional transition metal compound in the two-dimensional transition metal compound pattern array is molybdenum disulfide or tungsten diselenide; the shape of the two-dimensional transition metal compound domain is hexagonal, and the size of a single domain is 0.5-50 microns.

[0010] Preferably, the nitride Micro / Nano-LED array comprises n-type doped nitride, multi-quantum well structure, p-type doped nitride and p-type doped gallium nitride which are sequentially stacked from bottom to top, and the thicknesses are 300-500 nm, 50-80 nm, 100-200 nm and 30-50 nm, respectively; the multi-quantum well structure is alternately stacked with indium gallium nitride and gallium nitride, and the period is 10.

[0011] Preferably, the photosensitive composite filling layer is composed of photosensitive polymer and metal nanoparticles, the photosensitive polymer is SU-8, n-loft or NOA63, and the metal nanoparticles are gold, silver, aluminum or platinum nanoparticles.

[0012] Preferably, the material of the common metal electrode is titanium, aluminum and gold, and the thicknesses of titanium, aluminum and gold are 18-22 nm, 27-35 nm and 48-55 nm, respectively. The material of the metal top electrode is nickel and gold, and the thicknesses of nickel and gold are 28-32 nm and 45-55 nm, respectively.

[0013] The second object of the application is to provide a preparation method of a multi-dimensional hybrid Micro / Nano LED array, which specifically comprises the following steps: S1. providing a substrate and growing a continuous double-layer graphene film in situ on the substrate; S2. using an ultrafast pulsed laser to induce a defective graphene film on the double-layer graphene film; S3. growing a two-dimensional transition metal compound at the defect sites of the defective graphene film to form a two-dimensional transition metal compound pattern array; S4. sequentially depositing n-type doped nitride, multi-quantum well structure, p-type doped nitride and p-type doped gallium nitride on the two-dimensional transition metal compound pattern array to obtain a nitride Micro / Nano-LED array; S5. depositing a common metal electrode on the exposed graphene surface in the gap of the nitride Micro / Nano-LED array through photolithography, film plating and stripping processes; S6. Mix the metal nanoparticles with the photosensitive polymer to obtain a photosensitive polymer-metal nanoparticle filling; the photosensitive polymer-metal nanoparticle filling is prepared into the gap of the Micro / Nano-LED array by spin coating or spraying; the photosensitive polymer-metal nanoparticle filling is cured by ultraviolet light, and then the excess photosensitive polymer-metal nanoparticle filling on the top is removed, so that the p-type doped gallium nitride on the top layer of the nitride Micro / Nano-LED array is exposed, and a photosensitive composite filling layer is obtained; S7. A metal top electrode is prepared on the p-type doped gallium nitride on the top layer of the nitride Micro / Nano-LED array by a photolithography, film plating and stripping process.

[0014] Preferably, the in-situ growth in step S1 is performed by a high-temperature chemical vapor deposition method or a plasma-assisted molecular beam epitaxy method. The time resolution of the ultrafast pulsed laser in step S2 is in the order of picoseconds to femtoseconds, the spot diameter is 200-500 nanometers, and the wavelength is 400-1100 nanometers. In step S3, the two-dimensional transition metal compound is grown by a metal organic chemical vapor deposition method, a chemical vapor deposition method or a hydrothermal synthesis method; and the two-dimensional transition metal compound is molybdenum disulfide or tungsten diselenide.

[0015] Preferably, step S6 specifically comprises the following substeps: S601. Prepare a photosensitive polymer solution; mix and stir a colloidal solution of metal nanoparticles with the photosensitive polymer solution to obtain a photosensitive polymer-metal nanoparticle filling. S602. Fill the photosensitive polymer-metal nanoparticle filling into the gap of the nitride Micro / Nano-LED array by spin coating, and the spin coating parameters are 2500-3500 revolutions per minute and 20-40 seconds; the thickness of the prepared photosensitive polymer-metal nanoparticle filling is slightly higher than that of the nitride Micro / Nano-LED array structure, and the photosensitive polymer-metal nanoparticle filling completely covers the p-type doped gallium nitride layer on the top of the structure. S603. Expose the filled photosensitive polymer-metal nanoparticle filling to ultraviolet light for 8-15 minutes to make it harden and lose fluidity. S604. Use a gallium nitride epitaxial wafer as a mechanical polishing disc to remove the excess photosensitive polymer-metal nanoparticle filling on the top by mechanical polishing, so that the p-type doped gallium nitride on the top layer of the nitride Micro / Nano-LED array is exposed, and a photosensitive composite filling layer is obtained.

[0016] Compared with the prior art, the application can achieve the following beneficial effects: The application provides a multi-dimensional hybrid Micro / Nano-LED array and a preparation method thereof. The array is manufactured by using point defects on graphene, controllable growth of two-dimensional transition metal compounds and Micro / Nano-LED device arrays. The physical essence is the difference in nucleation energy barriers of various materials adsorbed under the defect regulation of two-dimensional materials. The method has the advantages of simple process and strong controllability. Compared with the conventional SiO2 mask pattern processing, the threshold energy required for inducing defects in graphene is lower, and no obvious thermal effect and damage to the sapphire substrate will be caused. In the device structure, graphene and two-dimensional transition metal compounds with high conductivity and carrier mobility can be used as transparent conductive electrodes and electron transport / injection layers of Micro / Nano-LED devices, respectively, which eliminates the mesa etching and mass transfer process required for the preparation of the bottom electrode. More importantly, the gap between the Micro / Nano-LED array is filled with a photosensitive polymer + metal nanoparticle, which passivates the device sidewall and suppresses the performance degradation caused by water and oxygen contact. On the other hand, the metal nanoparticles provide a scattering path for side light emission, improving the light-emitting efficiency and being suitable for manufacturing super-high-resolution display screens or near-eye imaging devices. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 FIG. 1 is a structural schematic diagram of a multi-dimensional hybrid Micro / Nano LED array according to an embodiment of the application.

[0018] Figure 2 FIG. 2 is a preparation process flowchart of a multi-dimensional hybrid Micro / Nano LED array according to an embodiment of the application.

[0019] REFERENCE SIGNS: 1. substrate; 2. defect graphene film; 2-1. ultrafast pulsed laser; 2-2. double-layer graphene film; 3. co-metal electrode; 4. two-dimensional transition metal compound pattern array; 5. n-type doped nitride; 6. multi-quantum well structure; 7. p-type doped nitride; 8. p-type doped gallium nitride; 9. metal top electrode; 10. photosensitive composite filling layer. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the application will be described with reference to the accompanying drawings. In the following description, the same modules are denoted by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, the detailed description thereof will not be repeated.

[0021] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not constitute a limitation on the present application.

[0022] Referring to Figure 1 The present application provides a multi-dimensional hybrid Micro / Nano LED array based on zero-dimensional, two-dimensional and three-dimensional, which comprises from bottom to top: a substrate 1; a defective graphene film 2 located on the upper surface of the substrate 1; a two-dimensional transition metal compound pattern array 4 located at the defect sites of the defective graphene film 2; a common metal electrode 3 located on the area of the defective graphene film 2 not covered by the two-dimensional transition metal compound pattern array 4; the common metal electrode 3 forms an interconnected network structure; a nitride Micro / Nano-LED array stacked only on the two-dimensional transition metal compound pattern array 4; a metal top electrode 9 located on the upper surface of the nitride Micro / Nano-LED array; a light-sensitive composite filling layer 10 located in the gap area not covered by the nitride Micro / Nano-LED array, maintaining the same height as the top end of the nitride Micro / Nano-LED array, and closely adhering to the exposed part of the defective graphene film 2.

[0023] Specifically, the substrate 1 is a sapphire substrate; The defective graphene film 2 is prepared by forming defect sites on a continuous double-layer graphene film 2-2 on the substrate 1 by laser induction; the thickness of the continuous double-layer graphene film 2-2 is less than 1 nanometer; the defect sites can be circular, polygonal, elliptical or other irregular patterns, with a characteristic size (maximum line width) of 200-500 nanometers; The material of the common metal electrode 3 is titanium, aluminum and gold, and the thicknesses of titanium, aluminum and gold are 20, 30 and 50 nanometers, respectively; The number of layers of the two-dimensional transition metal compound pattern array 4 is greater than 3, and the thickness is less than 3 nanometers; the two-dimensional transition metal compound in the two-dimensional transition metal compound pattern array 4 is molybdenum disulfide or tungsten diselenide; the shape of the two-dimensional transition metal compound crystal domain in the two-dimensional transition metal compound pattern array 4 is hexagonal, and the size of a single crystal domain is 0.5-50 microns; The size of the nitride Micro / Nano-LED array is consistent with or slightly larger than the two-dimensional transition metal compound pattern array 4; the nitride Micro / Nano-LED array comprises, from bottom to top, n-type doped nitride 5, multi-quantum well structure 6, p-type doped nitride 7, and p-type doped gallium nitride 8, with thicknesses of 300-500 nanometers, 50-80 nanometers, 100-200 nanometers, and 30-50 nanometers, respectively; wherein the multi-quantum well structure has a period of 10, and indium gallium nitride and gallium nitride are alternately stacked; The material of the metal top electrode 9 is nickel and gold, and the thicknesses are 30 nanometers and 50 nanometers, respectively; the metal top electrodes 9 are independent of each other; The photosensitive composite filling layer 10 is composed of a photosensitive polymer and metal nanoparticles; the photosensitive polymer is selected from SU-8, n-loft, or NOA63, and the metal nanoparticles are gold, silver, aluminum, or platinum nanoparticles; For Micro-LED, the size of the two-dimensional transition metal compound is controlled to be 5-50 micrometers; for Nano-LED, the size of the two-dimensional transition metal compound is controlled to be 0.5-1 micrometer.

[0024] Referring to Figure 2 The application further provides a preparation method of a multi-dimensional mixed Micro / Nano LED array, which is used to solve a series of technical problems such as high technical difficulty, poor controllability, and low device light-emitting efficiency of the Micro / Nano-LED device array preparation technology; and specifically comprises the following steps: S1. A substrate 1 is provided, and a continuous double-layer graphene film 2-2 is grown in situ on the substrate 1; Preferably, the in-situ growth adopts a high-temperature chemical vapor deposition method or a plasma-assisted molecular beam epitaxy method; In specific embodiments, the substrate 1 is a sapphire substrate.

[0025] S2. A superfast pulsed laser 2-1 is used to controllably induce a point defect arrangement on the double-layer graphene film 2-2, to form a defective graphene film 2; the characteristics of the defects are determined by laser intensity, action time, and spot size; Preferably, the time resolution of the superfast pulsed laser 2-1 is in the order of picoseconds to femtoseconds, the spot diameter is 200-500 nanometers, the wavelength covers 400-1100 nanometers, and the energy is in the order of millijoules.

[0026] S3. A two-dimensional transition metal compound is grown at the defect sites of the defective graphene film 2, to form a two-dimensional transition metal compound pattern array 4; Preferably, the two-dimensional transition metal compound is grown by a metal organic chemical vapor deposition method, a chemical vapor deposition method, or a hydrothermal synthesis method; the two-dimensional transition metal compound is molybdenum disulfide or tungsten diselenide; The defect site has a lower adsorption nucleation energy barrier, and by supplying a high flow of a sulfur source or a selenium source, the crystal domain is hexagonal; In specific embodiments, the two-dimensional transition metal compound is grown by metal organic chemical vapor deposition; the two-dimensional transition metal compound is molybdenum disulfide, and hexacarbonylmolybdenum and hydrogen sulfide are used as the molybdenum source and the sulfur source for growing the molybdenum disulfide, respectively; the flow ratio of the sulfur source to the molybdenum source is greater than 10, the growth temperature is 850 degrees Celsius, the growth time is 30-60 minutes, and the corresponding hexagonal molybdenum disulfide crystal domain size formed is 200-800 nanometers, and the number of layers is 3.

[0027] S4. Based on the difference in adsorption energy of nitride on the surface of graphene and two-dimensional transition metal compound, selectively grow a nitride Micro / Nano-LED array on the two-dimensional transition metal compound pattern array 4; specifically, use a metal-organic chemical vapor deposition equipment to sequentially grow an n-type doped nitride 5, a multi-quantum well structure 6, a p-type doped nitride 7, and a p-type doped gallium nitride 8; Preferably, the thicknesses of the n-type doped nitride 5, the multi-quantum well structure 6, the p-type doped nitride 7, and the p-type doped gallium nitride 8 are 300-500 nanometers, 50-80 nanometers, 100-200 nanometers, and 30-50 nanometers, respectively; and the multi-quantum well structure period is 10. In specific embodiments, the thicknesses of the n-type doped nitride 5, the multi-quantum well structure 6, the p-type doped nitride 7, and the p-type doped gallium nitride 8 are 300 nanometers, 60 nanometers (period 10), 100 nanometers, and 30 nanometers, respectively.

[0028] S5. Through semiconductor processes such as photolithography, film plating, and stripping, prepare a titanium / aluminum / gold electrode, i.e., a common metal electrode 3, on the surface of the graphene film 2 exposed at the gap of the nitride Micro / Nano-LED array; the common metal electrode 3 forms a common interconnection network; In specific embodiments, the thicknesses of titanium, aluminum, and gold in the common metal electrode 3 are 20, 30, and 50 nanometers, respectively.

[0029] S6. Mix zero-dimensional metal nanoparticles with a photosensitive polymer to obtain a photosensitive polymer-metal nanoparticle filler; use a spin coating or spraying method to prepare the photosensitive polymer-metal nanoparticle filler to the gap of the Micro / Nano-LED array; through ultraviolet curing, and then through mechanical polishing, remove the excess photosensitive polymer-metal nanoparticle filler on the top to stop the exposure of the p-type doped gallium nitride 8 on the top layer of the nitride Micro / Nano-LED array, and obtain a photosensitive composite filling layer 10; Preferably, the specific steps include the following sub-steps: S601. Preparing a photosensitive polymer solution; mixing and stirring a colloidal solution of metal nanoparticles with the photosensitive polymer solution to obtain a photosensitive polymer-metal nanoparticle filler; Specifically, the metal nanoparticles are gold, silver, aluminum or platinum nanoparticles; the colloidal solution of metal nanoparticles is prepared by solution synthesis, in which the metal nanoparticles are dissolved in ethanol, acetone or cyclopentanone. The photosensitive polymer solution is prepared by dissolving photosensitive polymers SU-8, n-loft or NOA63 in solvents such as ethanol, acetone or cyclopentanone. S602. Filling the photosensitive polymer-metal nanoparticle filler into the gap of the nitride Micro / Nano-LED array by spin coating, with a spin coating parameter of 2500-3500 rpm for 20-40 seconds; the prepared photosensitive polymer-metal nanoparticle filler has a thickness slightly higher than the nitride Micro / Nano-LED array structure, completely covering the p-type doped gallium nitride 8 on the top of the structure. S603. Exposing the filled photosensitive polymer-metal nanoparticle filler to ultraviolet light for 8-15 minutes to make it harden and lose fluidity. S604. Using a gallium nitride epitaxial wafer as a mechanical polishing disc, removing the excess photosensitive polymer-metal nanoparticle filler on the top by mechanical polishing to expose the p-type doped gallium nitride 8 on the top layer of the nitride Micro / Nano-LED array, and obtaining a photosensitive composite filling layer.

[0030] S7. Preparing independent metal top electrodes 9 on the p-type doped gallium nitride 8 on the top layer of the nitride Micro / Nano-LED array by semiconductor processes such as photolithography, film plating and stripping, for controlling the on-off of individual LEDs. Preferably, the metal top electrode 9 is a nickel / gold alloy electrode, in which the thickness of nickel and gold is 30 nm and 50 nm, respectively.

[0031] Example 1 This embodiment provides a preparation method of a multi-dimensional hybrid Micro / Nano LED array, taking indium gallium nitride / gallium nitride blue light Nano-LED as an example, with a single pixel structure size of 800 nm, and a structure schematic diagram as shown in FIG. 1. Figure 1 Specifically, the method comprises the following steps: S1. The substrate 1 is a sapphire substrate; a continuous double-layer graphene film 2-2 is grown in situ on the substrate 1 by high-temperature chemical vapor deposition.

[0032] S2. A titanium sapphire femtosecond laser is used as a light source (pulse width less than 10 femtoseconds), the spot diameter is 200-500 nanometers, the base wavelength range is 680-1100 nanometers, and the laser energy can reach the millijoule level after frequency doubling to 340-550 nanometers through a nonlinear crystal; an ultrashort pulse laser 2-1 with a wavelength of 400 nanometers after frequency doubling is used to induce defects in a double-layer graphene film 2-2, and the output light power reaches 10 12 ~10 13 Watts per square centimeter, and the light spot diameter is modulated to 500 nanometers through a conventional focusing system; the sample is placed on a high-precision displacement table, the sample moves in a two-dimensional plane through a stepping motor, the controllable stepping accuracy is 1 micrometer, the single-point laser irradiation time on the double-layer graphene film 2-2 is 10-100 nanoseconds, and the center distance between adjacent irradiation points is 2-5 micrometers, and finally a defective graphene film 2 is obtained.

[0033] S3. A two-dimensional transition metal compound is grown at the defect sites of the defective graphene film 2 by a metal organic chemical vapor deposition method, and a two-dimensional transition metal compound pattern array 4 is formed; the number and periodicity of the two-dimensional transition metal compound pattern array 4 are controlled by the defects induced on the double-layer graphene film 2-2; the two-dimensional transition metal compound is molybdenum disulfide, and hexacarbonylmolybdenum and hydrogen sulfide are used as the molybdenum source and the sulfur source for growing molybdenum disulfide, respectively; the flow ratio of the sulfur source to the molybdenum source should be greater than 10, the growth temperature is 850 degrees Celsius, and the growth time is 30-60 minutes, and the corresponding hexagonal molybdenum disulfide crystal domain size is about 200-800 nanometers, and the number of layers is 3.

[0034] S4. Based on the large electronegativity difference between the two-dimensional transition metal compound layers such as molybdenum disulfide, nitride atoms / molecules are easily adsorbed at the molybdenum disulfide crystal domain, and a nitride Micro / Nano-LED array is selectively grown on the two-dimensional transition metal compound pattern array 4; using a metal-organic chemical vapor deposition equipment, n-type doped nitride 5, multi-quantum well structure 6, p-type doped nitride 7 and p-type doped gallium nitride 8 are sequentially grown on the molybdenum disulfide crystal domain array, with thicknesses of 300 nanometers, 10 periods of 60 nanometers, 100 nanometers and 30 nanometers, respectively; the multi-quantum well structure 6 is an alternating layering of indium gallium nitride and gallium nitride; trimethyl gallium, trimethyl aluminum and ammonia are used as the gallium source, the aluminum source and the nitrogen source, respectively; due to the limitation of lateral epitaxy, the lateral size of the nitride Micro / Nano-LED array is slightly larger than that of the molybdenum disulfide crystal domain, about 300-900 nanometers, and the center light emission wavelength is 450 nanometers; in this embodiment, the nitride Micro / Nano-LED array is a gallium nitride blue light Nano-LED array.

[0035] S5. Through semiconductor processes such as photolithography, film plating and stripping, a titanium film, an aluminum film and a gold film are sequentially deposited on the surface of the graphene film 2 exposed to defects in the gap of the nitride Micro / Nano-LED array, to obtain a co-metal electrode 3. The co-metal electrode 3 forms a common interconnection network to supply power to all devices in the Micro / Nano-LED array. The thicknesses of titanium, aluminum and gold in the co-metal electrode 3 are 20, 30 and 50 nanometers respectively.

[0036] S6. The photosensitive composite filling layer 10 is prepared; specifically including the following sub-steps: S601. The SU8 photosensitive polymer is diluted in cyclopentanone to form a photosensitive polymer solution with a mass fraction of 5-10%. Metal nanoparticles are selected to be silver nanoparticle colloid solution matched with the light-emitting wavelength, which is mixed and stirred with the photosensitive polymer solution to obtain a photosensitive polymer-metal nanoparticle filler; The silver nanoparticle colloid solution is prepared by solution method, and is prepared by dissolving silver in ethanol, acetone or cyclopentanone; Specifically, the diameter of the silver nanoparticles is between 400-500 nanometers, and after mixing with the photosensitive polymer, the distribution density of the silver nanoparticles is 10 7 ~10 8 / cubic centimeter; S602. The photosensitive polymer-metal nanoparticle filler is filled into the gap of the nitride Micro / Nano-LED array by spin coating, and the spin coating parameters are 3000 rpm and 30 seconds; the thickness of the prepared photosensitive polymer-metal nanoparticle filler is slightly higher than that of the nitride Micro / Nano-LED array structure, and completely covers the p-type doped gallium nitride 8 on the top of the structure; S603. The filled photosensitive polymer-metal nanoparticle filler is exposed to ultraviolet light for 10 minutes to make it harden and lose fluidity; S604. The gallium nitride epitaxial wafer is used as a mechanical polishing disc, and the excess photosensitive polymer-metal nanoparticle filler on the top is removed by mechanical polishing. Since the hardness of the polishing disc is consistent with the p-type doped gallium nitride 8 on the top layer of the LED and much higher than that of the photosensitive polymer, the mechanical polishing will automatically stop after the p-type doped gallium nitride 8 is polished, to obtain the photosensitive composite filling layer 10. In addition, the gallium nitride epitaxial wafer has an atomic level flatness, which can also ensure the flatness and uniformity of the polished surface when used as a mechanical polishing disc.

[0037] S7. Using semiconductor processes such as photolithography, electron beam evaporation and organic solvent stripping, nickel and gold are deposited on the p-type doped gallium nitride 8 on the top layer of the nitride Micro / Nano-LED array, with thicknesses of 30 nm and 50 nm respectively, to prepare a plurality of independent metal top electrodes 9; the preparation of the multi-dimensional hybrid Micro / Nano LED array is completed. The flow chart is shown in Figure 2 .

[0038] The defective graphene film 2 and molybdenum disulfide in the embodiment are used to regulate the nucleation growth position and size of the gallium nitride blue light Nano-LED, graphene is used as a transparent conductive electrode, molybdenum disulfide is used as an electron injection layer / transport layer, and Ag nanoparticles provide scattering paths for the light emitted in the multi-quantum well, thereby improving the light-emitting efficiency of the Nano-LED device array in multiple dimensions.

[0039] It should be understood that the various forms of flow shown above can be reordered, added to, or deleted from. For example, the steps described in the present disclosure can be executed in parallel, in sequence, or in a different order, as long as the desired results of the technical solutions of the present disclosure can be achieved, and the present disclosure is not limited herein.

[0040] The above detailed description does not constitute a limitation on the scope of protection of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A multi-dimensional hybrid Micro / Nano LED array, characterized in that: From bottom to top, this includes: Substrate; A defective graphene film located on the upper surface of the substrate; A two-dimensional array of transition metal compounds located at the defect sites of a defective graphene film; The common metal electrode is located in the region of the defective graphene film that is not covered by the two-dimensional transition metal compound pattern array. Nitride Micro / Nano-LED arrays are stacked only on a two-dimensional transition metal compound patterned array; The metal top electrode is located on the upper surface of the nitride Micro / Nano-LED array; The photosensitive composite filling layer is located in the gap region not covered by the nitride Micro / Nano-LED array, and is at the same height as the top of the nitride Micro / Nano-LED array.

2. The multi-dimensional hybrid Micro / Nano LED array according to claim 1, characterized in that: The defective graphene film is prepared by laser-induced formation of defect sites on a continuous bilayer graphene film on the substrate. The thickness of the bilayer graphene film is less than 1 nanometer; the characteristic size of the defect sites is 200~500 nanometers.

3. The multi-dimensional hybrid Micro / Nano LED array according to claim 1, characterized in that: The two-dimensional transition metal compound patterned array has more than 3 layers and a thickness of less than 3 nanometers.

4. The multi-dimensional hybrid Micro / Nano LED array according to claim 3, characterized in that: The two-dimensional transition metal compound pattern array contains molybdenum disulfide or tungsten diselenide as the two-dimensional transition metal compound. The crystal domains of the two-dimensional transition metal compound are hexagonal in shape, and the size of a single crystal domain is 0.5 to 50 micrometers.

5. The multi-dimensional hybrid Micro / Nano LED array according to claim 1, characterized in that: The nitride Micro / Nano-LED array comprises, from bottom to top, n-type doped nitride, a multi-quantum-well structure, p-type doped nitride, and p-type doped gallium nitride, with thicknesses of 300-500 nm, 50-80 nm, 100-200 nm, and 30-50 nm, respectively; the multi-quantum-well structure is composed of alternating layers of indium gallium nitride and gallium nitride, with a period of 10.

6. The multi-dimensional hybrid Micro / Nano LED array according to claim 1, characterized in that: The photosensitive composite filler layer is composed of a photosensitive polymer and metal nanoparticles. The photosensitive polymer is SU-8, n-loft, or NOA63, and the metal nanoparticles are gold, silver, aluminum, or platinum nanoparticles.

7. A multi-dimensional hybrid Micro / Nano LED array according to claim 1, characterized in that: The materials of the common metal electrode are titanium, aluminum and gold, and the thicknesses of titanium, aluminum and gold are 18~22 nanometers, 27~35 nanometers and 48~55 nanometers, respectively. The metal top electrode is made of nickel and gold, with thicknesses of 28-32 nanometers and 45-55 nanometers, respectively.

8. A method for fabricating a multi-dimensional hybrid Micro / Nano LED array, characterized in that: Specifically, the steps include the following: S1. Provide a substrate and grow a continuous bilayer graphene film in situ on the substrate; S2. Using ultrafast pulsed lasers to induce the formation of defective graphene films on bilayer graphene films; S3. Two-dimensional transition metal compounds are grown at the defect sites on the defective graphene film to form a two-dimensional transition metal compound pattern array. S4. An n-type doped nitride, a multi-quantum-well structure, a p-type doped nitride, and a p-type doped gallium nitride are sequentially deposited on a two-dimensional transition metal compound pattern array to obtain a nitride Micro / Nano-LED array. S5. Through photolithography, coating and lift-off processes, the exposed graphene surface in the gaps of the nitride Micro / Nano-LED array is deposited onto the common metal electrode; S6. Mix metal nanoparticles with a photosensitive polymer to obtain a photosensitive polymer-metal nanoparticle filler; apply the photosensitive polymer-metal nanoparticle filler to the gaps of the Micro / Nano-LED array by spin coating or spraying; cure with ultraviolet light, and then remove the excess photosensitive polymer-metal nanoparticle filler from the top to expose the p-type doped gallium nitride on the top layer of the nitride Micro / Nano-LED array, thus obtaining a photosensitive composite filler layer; S7. A metal top electrode is fabricated on p-type doped gallium nitride on the top layer of a nitride Micro / Nano-LED array using photolithography, coating, and lift-off processes.

9. The method for fabricating a multi-dimensional hybrid Micro / Nano LED array according to claim 8, characterized in that: The in-situ growth in step S1 is performed using high-temperature chemical vapor deposition or plasma-assisted molecular beam epitaxy. In step S2, the temporal resolution of the ultrafast pulsed laser is on the picosecond to femtosecond scale, the spot diameter is 200-500 nanometers, and the wavelength is 400-1100 nanometers. In step S3, a two-dimensional transition metal compound is grown using metal-organic chemical vapor deposition, chemical vapor deposition, or hydrothermal synthesis; the two-dimensional transition metal compound is molybdenum disulfide or tungsten diselenide.

10. The method for fabricating a multi-dimensional hybrid Micro / Nano LED array according to claim 8, characterized in that: Step S6 specifically includes the following sub-steps: S601. Prepare a photosensitive polymer solution; mix and stir the colloidal solution of metal nanoparticles with the photosensitive polymer solution to obtain a photosensitive polymer-metal nanoparticle filler; S602. Photosensitive polymer-metal nanoparticle filler is filled into the gaps of nitride Micro / Nano-LED array by spin coating. The spin coating parameters are: 2500~3500 rpm, time 20~40 seconds. The thickness of the prepared photosensitive polymer-metal nanoparticle filler is slightly higher than the nitride Micro / Nano-LED array structure, completely covering the p-type doped gallium nitride layer on the top of the structure. S603. Expose the filled photosensitive polymer-metal nanoparticle filler under a UV lamp for 8-15 minutes to solidify and harden it, causing it to lose its fluidity; S604. Using a gallium nitride epitaxial wafer as a mechanical polishing pad, excess photosensitive polymer-metal nanoparticle filler on the top is removed by mechanical polishing, exposing the p-type doped gallium nitride on the top layer of the nitride Micro / Nano-LED array to obtain a photosensitive composite filler layer.

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