CN118335857A - Luminescent particle color conversion layer and preparation method and application thereof - Google Patents
Luminescent particle color conversion layer and preparation method and application thereof Download PDFInfo
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Abstract
The invention discloses a luminescent particle color conversion layer and a preparation method and application thereof, wherein an epitaxial structure is simplified, only an active region (luminescent layer) is grown to prepare high-quality luminescent particles, luminescent particle etching damage introduced by dry etching is further removed through chemical treatment and wet etching, the surface morphology of the luminescent particles is regulated and controlled, the luminescent quality is improved, luminescent particles with relatively stable chemical properties are used as a color conversion layer material, and a Micro LED luminescent device for realizing full-color display is prepared by combining blue light or ultraviolet Micro LEDs, so that the stability of the device is improved, and the service life of the device is prolonged.
Description
Technical Field
The invention belongs to the technical field of semiconductor preparation, and particularly relates to a luminescent particle color conversion layer, a preparation method and application thereof.
Background
Compared with the traditional Liquid CRYSTAL DISPLAY, LCD technology and Organic LIGHT EMITTING Diodes (OLED) technology which can be produced in large scale, micro light emitting Diodes (Micro LightEmitting Diodes, micro LEDs) based on III-V compound semiconductor materials have more excellent performance advantages in almost all dimensions, and the Micro LEDs are high in efficiency, long in service life, small in size, high in contrast ratio, quick in response, high in resolution and the like, so that the Micro LEDs are greatly expanded in the display field.
In order to realize full-color display, subpixels of three colors of red, green and blue need to be integrally manufactured on a single pixel point, although the III-V group compound semiconductor has the advantages of stable chemical property and capability of realizing light emission covering the whole visible light band by regulating chemical composition, in the preparation process of the III-V group semiconductor Micro LED, on one hand, the defect density of an epitaxial layer is higher due to lattice mismatch and thermal mismatch between epitaxial layers, the crystal quality is poor, the injection efficiency of the device is reduced, and on the other hand, the light emitted by radiation of an active region is totally reflected at all interfaces and is absorbed again due to refractive index difference between the epitaxial layers and air, and the epitaxial layers, so that the light emitting efficiency of the chip is reduced. Meanwhile, in the device preparation process, the damage introduced by the conventional dry etching process further reduces the luminous efficiency of the device, and meanwhile, the realization of full-color display also faces the difficulty of mass transfer, so that the product yield is low.
In the prior art, a chemical synthesis method is adopted, a series of chemical reactions are carried out in a solution to prepare a quantum dot color conversion layer, the luminescent color is changed by regulating and controlling the size of synthesized quantum dots, and the color conversion layer with three colors of red, green and blue can be combined with blue light or ultraviolet LEDs to realize full-color display. However, the color conversion layer material of the display chip obtained by the method has the problem of performance degradation under the environments of oxygen, water vapor and the like, so that the service life of the light-emitting device is reduced, and meanwhile, impurities can be introduced in the preparation process to cause the impurity of the product.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.
Disclosure of Invention
The invention aims to provide a luminescent particle color conversion layer, a preparation method and application thereof, which can improve the stability and the service life of a device.
In order to achieve the above object, a specific embodiment of the present invention provides a method for preparing a color conversion layer of luminescent particles, including:
providing a substrate, and growing a sacrificial layer on the surface of the substrate;
Growing a light-emitting layer on the surface of the sacrificial layer;
etching the light-emitting layer until the sacrificial layer is exposed, so that the light-emitting layer forms a plurality of light-emitting particles;
Etching the sacrificial layer to separate the luminescent particles from the substrate;
Removing etching damage of the luminescent particles by adopting chemical treatment, and regulating and controlling the surface morphology of the luminescent particles;
providing a light-transmitting polymer solution, dispersing the luminescent particles in the polymer solution, and curing to form a color conversion layer.
In one or more embodiments of the invention, the chemical composition of the light emitting layer is Al mInnGa1-m-n N or Al mInnGa1-m-n P or Al mInnGa1-m-n As, wherein 0.ltoreq.m.ltoreq.1, 0.ltoreq.n.ltoreq.1, 0.ltoreq.1-m-n.ltoreq.1.
In one or more embodiments of the present invention, the thickness of the light emitting layer is 100nm to 500nm.
In one or more embodiments of the present invention, the chemical composition ratio in the light emitting layer is adjusted to prepare light emitting layers of different colors.
In one or more embodiments of the invention, the sacrificial layer has a chemical composition of Al xInyGa1-x-y N or Al xInyGa1-x-y P or Al xInyGa1-x-y As, wherein 0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, 0.ltoreq.1-x-y.ltoreq.1.
In one or more embodiments of the present invention, the sacrificial layer is a heavily doped layer, and the doping element includes silicon or germanium, and the doping concentration is not less than 5E18cm -3.
In one or more embodiments of the invention, the sacrificial layer has a thickness in the range of 100nm to 500nm.
In one or more embodiments of the invention, the chemically treated reagent comprises one or more of tetramethylammonium hydroxide, potassium hydroxide, ammonia, phosphoric acid, hydrochloric acid, hydrobromic acid, nitric acid, concentrated sulfuric acid, hydrogen peroxide, ethylene glycol.
An embodiment of the present invention provides a color conversion layer, which is prepared by the method for preparing the color conversion layer of luminescent particles.
An embodiment of the present invention provides a light emitting device including:
The blue light or ultraviolet Micro LED chip comprises a plurality of luminous pixel units arranged in an array;
the light resistance layer is arranged on the light emitting surface of the blue light or ultraviolet Micro LED chip, a plurality of windows are arranged on the light resistance layer in a penetrating mode, and the windows expose the luminous pixel units;
The color conversion layer is arranged on the luminous pixel units in the window.
In one or more embodiments of the present invention, the light emitted by the luminescent particles in the color conversion layer on several of the light emitting pixel units is all the same, or partially the same, or is all different.
In one or more embodiments of the present invention, the material of the photoresist layer is an opaque material, including a black photoresist or a black epoxy.
An embodiment of the present invention provides a method for manufacturing a light emitting device, including:
providing a substrate, and growing a sacrificial layer on the surface of the substrate;
Growing a light-emitting layer on the surface of the sacrificial layer;
etching the light-emitting layer until the sacrificial layer is exposed, so that the light-emitting layer forms a plurality of light-emitting particles;
Etching the sacrificial layer to separate the luminescent particles from the substrate;
Removing etching damage of the luminescent particles by adopting chemical treatment, and regulating and controlling the surface morphology of the luminescent particles;
providing a light-transmitting polymer solution, and dispersing the luminescent particles in the polymer solution;
Providing a blue light or ultraviolet Micro LED chip, wherein the blue light or ultraviolet Micro LED chip comprises a plurality of luminous pixel units arranged in an array;
Forming a photoresist layer on the light emitting surface of the blue light or ultraviolet Micro LED chip, wherein a plurality of through windows are formed on the photoresist layer, and the windows expose the luminous pixel units;
And respectively coating the polymer solution containing the luminescent particles on the luminescent pixel units in the window and curing.
Compared with the prior art, the luminescent particle color conversion layer, the preparation method and the application thereof adopt luminescent particles with relatively stable chemical properties as the color conversion layer material, and are combined with blue light or ultraviolet Micro LEDs to prepare the Micro LED luminescent device capable of realizing full-color display, so that the stability of the device is improved and the service life of the device is prolonged.
According to the luminescent particle color conversion layer, the preparation method and the application thereof, an epitaxial structure is simplified when luminescent particles are prepared, and only an active region (a luminescent layer) is required to be grown, so that thermal degradation of the active region (the luminescent layer) caused by subsequent growth of a p-type layer in a conventional full-structure LED can be avoided.
According to the luminescent particle color conversion layer, the preparation method and the application thereof, luminescent particle etching damage introduced by dry etching is removed through chemical treatment wet etching, the luminescent quality of the luminescent layer is improved, other impurities are not introduced, and the high-quality luminescent particle color conversion layer can be prepared.
According to the luminescent particle color conversion layer, the preparation method and the application thereof, the surface morphology of the luminescent particles is regulated and controlled by defining the shape of the luminescent particles with specific crystal face orientation and combining the corrosive agent capable of corroding along the specific crystal face, so that the luminescent quality is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.
FIG. 1 is a process flow diagram of a method for preparing a color conversion layer of luminescent particles according to an embodiment of the invention;
fig. 2 is a schematic structural view of a light emitting device according to an embodiment of the present invention;
FIG. 3 is a process flow diagram of a method of fabricating a light emitting device according to an embodiment of the present invention;
FIGS. 4 a-4 e are schematic views illustrating steps of a method for fabricating a light emitting device according to an embodiment of the present invention;
Fig. 5 a-5 c are schematic diagrams illustrating surface morphology control of luminescent particles according to an embodiment of the invention.
Detailed Description
In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
As described in the background art, the preparation of Micro LED full-color display chips in the prior art requires the growth of complete LED structures, which requires the further reduction of the growth temperature, especially for red LEDs, when p-type regions are grown, and this step leads to a reduction in material quality. After the Micro LED device with three colors of red, green and blue is prepared, the sub-pixels are arranged on the substrate in a stripping and transferring mode to obtain the full-color display chip. The other mode is to realize full-color display by combining a blue light or ultraviolet Micro LED with a chemically synthesized quantum dot color conversion material, but the quantum dot material is extremely sensitive to the environment and faces the problem of material stability, so that the service life of the light-emitting device is not high, and meanwhile, impurities can be possibly introduced in the preparation process to cause the impurity of the product.
However, the combination of a blue light or ultraviolet Micro LED array and a color conversion layer is a feasible full-color scheme, and full-color display can be realized by converting part of blue light Micro LED pixels into red light and green light, or converting ultraviolet Micro LED pixels into red light, blue light and blue light of a target.
Based on the method, the application provides a luminescent particle color conversion layer, a preparation method and application thereof, and the luminescent particle color conversion layer is prepared by simplifying an epitaxial structure and only growing a luminescent layer (an active region), luminescent particle etching damage introduced by dry etching is further removed by chemical treatment and wet etching, the surface morphology of the luminescent particle is regulated and controlled, the luminescent quality is improved, III-V compound semiconductor luminescent particles with relatively stable chemical properties are used as a color conversion layer material, and a Micro LED luminescent device for realizing full-color display is prepared by combining blue light or ultraviolet Micro LEDs, so that the stability of the device is improved and the service life of the device is prolonged.
As shown in fig. 1, a method for preparing a color conversion layer of luminescent particles according to an embodiment of the present invention includes the following steps:
s1, providing a substrate, and growing a sacrificial layer on the surface of the substrate.
S2, growing a light-emitting layer on the surface of the sacrificial layer.
And S3, etching the light-emitting layer until the sacrificial layer is exposed, so that the light-emitting layer forms a plurality of light-emitting particles.
And S4, corroding the sacrificial layer to separate the luminescent particles from the substrate.
And S5, eliminating etching damage of the luminescent particles by adopting chemical treatment, and regulating and controlling the surface morphology of the luminescent particles.
S6, providing a light-transmitting polymer solution, dispersing luminescent particles in the polymer solution, and curing to form a color conversion layer.
In step S1, the substrate may be a sapphire substrate, a silicon carbide substrate, a nitride substrate or other substrate materials suitable for epitaxial growth, and the quality of the epitaxial layer material can be improved by using a homogeneous substrate. The chemical composition of the sacrificial layer is a III-V group compound semiconductor material such As Al xInyGa1-x-y N, al xInyGa1-x-y P, al xInyGa1-x-y As and the like, wherein x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, and 0 is more than or equal to 1-x-y is more than or equal to 1. The sacrificial layer is a heavily doped layer, the doping element can comprise silicon or germanium, and the doping concentration is not less than 5E18cm -3. The thickness of the sacrificial layer is 100 nm-500 nm.
In step S2, the light-emitting layer may be grown by metal-organic chemical vapor deposition, molecular beam epitaxy or other conventional epitaxy processes. The chemical composition of the luminous layer is a III-V group compound semiconductor material such As Al mInnGa1-m-n N, al mInnGa1-m-n P, al mInnGa1-m-n As and the like, wherein m is more than or equal to 0 and less than or equal to 1, N is more than or equal to 0 and less than or equal to 1, and 0 is more than or equal to 1-m-N is more than or equal to 1. The thickness of the light-emitting layer is 100 nm-500 nm. The light emitting layers of different colors, for example, red, blue, and green, yellow, etc., can be prepared by adjusting the chemical composition ratio in the light emitting layers.
In step S3, the shape of the luminescent particle defined by the photolithography and etching process may be any shape such as triangle, rectangle, hexagon, circle, etc. The choice of the orientation of the specific crystal planes of the luminescent layer material may be made to facilitate the subsequent etching of the sacrificial layer. The etching process requires that the etching depth from top to bottom is at least greater than the thickness of the light-emitting layer on the upper layer, so that the intermediate sacrificial layer is exposed.
In step S4, the sacrificial layer may be etched and stripped by an electrochemical etching method. Wherein, the anode of the electrochemical corrosion circuit is connected with the sacrificial layer, and the cathode is arranged in the electrolyte solution. The electrolyte solution is required to have little corrosion effect on the epitaxial structure when not electrified, and can realize corrosion on the sacrificial layer after the electrification, and the electrolyte solution can be oxalic acid solution, nitric acid solution and the like.
In the etching process, the sacrificial layer is a heavily doped layer, so that the resistivity of the sacrificial layer is far smaller than that of the luminescent layer and the substrate, selective etching can be realized, and the substrate stripped after etching can be reused.
In other embodiments, laser lift-off, mechanical lift-off, etc. may be used, depending on the actual sacrificial layer and light emitting layer materials.
After the completion of the peeling, the above luminescent particles were separated, washed and collected. The detergent can be absolute ethyl alcohol, deionized water and other liquid which can dissolve corrosive agents, does not react with the sample and is easy to remove. The collection and separation modes can be suction filtration, evaporation, precipitation and the like.
In step S5, the damage introduced in the etching process is eliminated by chemical treatment and dried, and the reagent used in the chemical treatment may be one or more of tetramethylammonium hydroxide solution, potassium hydroxide, ammonia water, phosphoric acid, hydrochloric acid, hydrobromic acid, nitric acid, concentrated sulfuric acid, hydrogen peroxide, ethylene glycol, and the like. In the process of carrying out chemical treatment on the luminous particles, the damage introduced by dry etching can be removed, the surface morphology of the luminous particles can be regulated and controlled by changing the included angle between the crystal face direction corroded by the corrosive agent and the defined direction of the dry etching, the corrosion temperature and the corrosion time, the total reflection at the interface is reduced, and the light extraction efficiency is improved.
In step S6, the polymer material used may be epoxy, polymethyl methacrylate or other light-transmitting, heat-resistant polymer material.
According to the preparation method of the luminescent particle color conversion layer, the epitaxial structure is simplified when the luminescent particles are prepared, and only the luminescent layer (active region) is required to be grown, so that the active region can be prevented from thermal degradation in the epitaxial process. In addition, in the process of carrying out chemical treatment on the luminescent particles, the damage introduced by dry etching can be removed, the surface morphology of the luminescent particles can be regulated and controlled, the total reflection at the interface is reduced, and the light extraction efficiency is improved.
It can be understood that in the prior art, epitaxial wafers with three luminescent colors of red, green and blue can be grown respectively by changing the chemical composition and components of the active region, and Micro LED device arrays with three colors of red, green and blue are prepared through a series of processes, and then transferred and arranged on a display substrate as sub-pixels to realize full-color display. For devices applied to full color display, the conventional preparation process is: through various epitaxial modes, a complete LED structure is grown on a substrate and mainly comprises an n-type layer, an active region (a light-emitting layer), an electron blocking layer and a p-type layer, and simultaneously positive and negative electrode metals are required to be deposited to realize light emission under electric injection. In order to ensure the growth quality of the p-type layer, the growth temperature of the p-type layer is higher than that of the active region (light-emitting layer), and at the higher temperature, the active region (light-emitting layer) is thermally decomposed to lower the light-emitting quality of the active region, so that the p-type layer has to be balanced at the growth temperature.
The invention simplifies the epitaxial structure when preparing the luminous particles, only needs to grow the luminous layer, and can avoid the thermal degradation of the active region (of the luminous layer) caused by the subsequent growth of the p-type layer in the conventional full-structure LED.
In addition, in the process of carrying out chemical treatment on the luminous particles, the corrosion inhibitor can remove a damaged area caused by dry etching, and a rough structure can be formed on the surface of the corroded particles by adopting the corrosion inhibitor with crystal face selectivity, so that the surface roughening is realized, and the light emergent efficiency is improved. According to the crystal face selectivity of the corrosive to the specific material, the micro morphology of the nano scale of the surface of the luminescent particle can be regulated and controlled by adjusting the included angle between the crystal face selection direction and the crystal face direction exposed by the dry etching.
Based on this, the invention also provides a luminescent particle color conversion layer comprising a polymer film and luminescent particles located within the polymer film.
Referring to fig. 2, the present invention also provides a light emitting device including a blue or ultraviolet Micro LED chip 10, a photoresist layer 20, and the above-mentioned color conversion layer 30.
The blue or ultraviolet Micro LED chip 10 may be an existing chip structure, which includes a plurality of light emitting pixel units 11 arranged in an array.
The photoresist layer 20 is disposed on the light emitting surface of the blue light or ultraviolet Micro LED chip 10, and a plurality of windows 21 are disposed on the photoresist layer 20 in a penetrating manner, wherein the windows 21 are disposed in one-to-one correspondence with the light emitting pixel units 11 and expose the light emitting pixel units 11. The material of the photoresist layer 20 is an opaque material, including black photoresist or black epoxy.
The color conversion layer 30 is disposed on the light emitting pixel unit 11 within the window 21. The light emitted by the luminescent particles in the color conversion layer 30 on several luminescent pixel units 11 is all the same, or partially the same, or all different.
Referring to fig. 3, the present invention also provides a method for manufacturing a light emitting device, comprising the steps of:
s10, providing a substrate, and growing a sacrificial layer on the surface of the substrate.
And S20, growing a light-emitting layer on the surface of the sacrificial layer.
And S30, etching the light-emitting layer until the sacrificial layer is exposed, so that the light-emitting layer forms a plurality of light-emitting particles.
And S40, corroding the sacrificial layer to separate the luminescent particles from the substrate.
S50, adopting chemical treatment to eliminate etching damage of the luminescent particles, and regulating and controlling the surface morphology of the luminescent particles.
And S60, providing a light-transmitting polymer solution, and dispersing the luminescent particles in the polymer solution.
S70, providing a blue light or ultraviolet Micro LED chip, wherein the blue light or ultraviolet Micro LED chip comprises a plurality of luminous pixel units arranged in an array.
S80, forming a photoresist layer on the light emitting surface of the blue light or ultraviolet Micro LED chip, wherein a plurality of through windows are formed on the photoresist layer, and the windows expose the luminous pixel units.
And S90, respectively coating the polymer solution containing the luminescent particles on the luminescent pixel units in the window and curing.
In step S10, the substrate may be a sapphire substrate, a silicon carbide substrate, a nitride substrate or other substrate materials suitable for epitaxial growth, and the quality of the epitaxial layer material can be improved by using a homogeneous substrate according to the composition of the sacrificial layer and the light-emitting layer. The chemical composition of the sacrificial layer is a III-V group compound semiconductor material such As Al xInyGa1-x-y N, al xInyGa1-x-y P, al xInyGa1-x-y As and the like, wherein x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, and 0 is more than or equal to 1-x-y is more than or equal to 1. The sacrificial layer is a heavily doped layer, the doping element can comprise silicon or germanium, and the doping concentration is not less than 5E18cm -3. The thickness of the sacrificial layer is 100 nm-500 nm.
In step S20, the light-emitting layer may be grown by metal-organic chemical vapor deposition, molecular beam epitaxy or other conventional epitaxy processes. The chemical composition of the luminous layer is a III-V group compound semiconductor material such As Al mInnGa1-m-n N, al mInnGa1-m-n P, al mInnGa1-m-n As and the like, wherein m is more than or equal to 0 and less than or equal to 1, N is more than or equal to 0 and less than or equal to 1, and 0 is more than or equal to 1-m-N is more than or equal to 1. The thickness of the light-emitting layer is 100 nm-500 nm. The light emitting layers of different colors, for example, red, blue, and green, yellow, etc., can be prepared by adjusting the chemical composition ratio in the light emitting layers.
In step S30, the shape of the luminescent particle defined by the photolithography and etching process may be any shape such as triangle, rectangle, hexagon, circle, etc. The choice of the orientation of the specific crystal planes of the luminescent layer material may be made to facilitate the subsequent etching of the sacrificial layer. The etching process requires that the etching depth from top to bottom is at least greater than the thickness of the light-emitting layer on the upper layer, so that the intermediate sacrificial layer is exposed.
In step S40, the sacrificial layer may be etched and stripped by an electrochemical etching method. Wherein, the anode of the electrochemical corrosion circuit is connected with the sacrificial layer, and the cathode is arranged in the electrolyte solution. The electrolyte solution is required to have little corrosion effect on the epitaxial structure when not electrified, and can realize corrosion on the sacrificial layer after the electrification, and the electrolyte solution can be oxalic acid solution, nitric acid solution and the like.
In the etching process, the sacrificial layer is a heavily doped layer, so that the resistivity of the sacrificial layer is far smaller than that of the luminescent layer and the substrate, selective etching can be realized, and the substrate stripped after etching can be reused.
In other embodiments, laser lift-off, mechanical lift-off, etc. may be used, depending on the actual sacrificial layer and light emitting layer materials.
After the completion of the peeling, the above luminescent particles were separated, washed and collected. The detergent can be absolute ethyl alcohol, deionized water and other liquid which can dissolve corrosive agents, does not react with the sample and is easy to remove. The collection and separation modes can be suction filtration, evaporation, precipitation and the like.
In step S50, the damage introduced in the etching process is eliminated by chemical treatment and dried, and the reagent used in the chemical treatment may be one or more of tetramethylammonium hydroxide solution, potassium hydroxide, ammonia water, phosphoric acid, hydrochloric acid, hydrobromic acid, nitric acid, concentrated sulfuric acid, hydrogen peroxide, ethylene glycol, and the like. In the process of carrying out chemical treatment on the luminescent particles, the method can remove the damage introduced by dry etching, regulate and control the surface morphology of the luminescent particles, reduce total reflection at the interface and improve the light extraction efficiency.
In step S60, the polymer material used may be epoxy, polymethyl methacrylate or other light-transmitting, heat-resistant polymer material.
In step S80, a photo-resist layer with a window is formed by filling a light blocking material between the light emitting pixel unit arrays of the blue light or ultraviolet Micro LED chip through a photolithography process, so as to reduce the crosstalk between the light emitting pixel units. The light blocking material can be opaque material such as black photoresist, black epoxy, etc.
In step S90, the polymer solution may be applied by spin coating, screen printing, ink jet printing, or the like. The light-emitting brightness can be adjusted by changing the mass fraction of the light-emitting particles in the polymer solution.
The technical scheme of the application is described in detail below through a specific embodiment.
Referring to fig. 4a, a sacrificial layer 200 capable of being electrochemically etched and a light emitting layer 300 having a specific light emitting wavelength are grown on a washed gallium nitride substrate 100, and the light emitting layer 300 may be a red light emitting layer, a blue light emitting layer and a light emitting layer.
Referring to fig. 4b and 4c, the size of the luminescent particles is defined by photolithography and etching, and then the epitaxial wafer is placed in an electrolytic cell 400, wherein an anode of a circuit power source 401 is connected to the sacrificial layer 200, and a cathode is placed in an electrolyte solution, and electrochemical etching is performed on the intermediate sacrificial layer 200 to obtain the luminescent particles.
Washing and separating the corroded luminescent particles from the electrolyte solution. The specific operation is as follows: adding absolute ethyl alcohol, putting into an ultrasonic machine cleaning machine, then pouring out supernatant, repeating the absolute ethyl alcohol washing flow, heating and drying, and soaking the washed luminous particles with a specific corrosive liquid according to the chemical composition of the luminous particles to remove the damage caused by etching.
Referring to fig. 5a to 5c, fig. 5a shows the crystal plane direction (first direction) of the luminescent particle exposed after dry etching, and by forming an angle between the crystal plane direction and the specific etching direction (second direction, having rotational symmetry) of the etchant, luminescent particles having different nano-scale surface morphology as shown in fig. 5b and 5c can be obtained, so that the surface of the luminescent particle is roughened, and the light extraction efficiency is improved.
Referring to fig. 4d, the photoresist layer 20 is prepared through a photolithography process. That is, black photoresist is filled between the arrays of the light emitting pixel units 11 of the blue Micro LED chip 10 to reduce inter-pixel crosstalk, and the light emitting pixel units 11 are exposed to serve as light emitting surfaces.
Referring to fig. 4e and 2, the steps of separating, washing and drying the light emitting particles are repeated, the light emitting particles are uniformly dispersed in the epoxy resin, and polymer solutions 31, 32 and 33 containing light emitting particles of three colors of red, green and blue are respectively coated on the blue Micro LED chip 10 through templates a, B and C having specific patterns, and filled in the window 21 of the photoresist layer 20, so that a specific portion of the blue Micro LED chip light emitting pixel units 11 is converted into green light or red light, thereby obtaining a Micro LED chip capable of realizing full color display.
Compared with the prior art, the luminescent particle color conversion layer, the preparation method and the application thereof adopt luminescent particles with relatively stable chemical properties as the color conversion layer material, and are combined with blue light or ultraviolet Micro LEDs to prepare the Micro LED luminescent device capable of realizing full-color display, so that the stability of the device is improved and the service life of the device is prolonged.
According to the luminescent particle color conversion layer, the preparation method and the application thereof, an epitaxial structure is simplified when luminescent particles are prepared, and only the luminescent layer is required to be grown, so that the thermal degradation of an active region (luminescent layer) caused by the subsequent growth of a p-type layer in a conventional full-structure LED can be avoided.
According to the luminescent particle color conversion layer, the preparation method and the application thereof, luminescent particle etching damage introduced by dry etching is removed through chemical treatment wet etching, the luminescent quality of the luminescent layer is improved, other impurities are not introduced, and the high-quality luminescent particle color conversion layer can be prepared.
According to the luminescent particle color conversion layer, the preparation method and the application thereof, the surface morphology of the luminescent particles is regulated and controlled by defining the shape of the luminescent particles with specific crystal face orientation and combining the corrosive agent capable of corroding along the specific crystal face, so that the luminescent quality is improved.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail below, and that the embodiments described in the examples may be combined as appropriate to form other embodiments that will be apparent to those skilled in the art.
Claims (10)
1. A method of producing a luminescent particle color conversion layer, comprising:
providing a substrate, and growing a sacrificial layer on the surface of the substrate;
Growing a light-emitting layer on the surface of the sacrificial layer;
etching the light-emitting layer until the sacrificial layer is exposed, so that the light-emitting layer forms a plurality of light-emitting particles;
Etching the sacrificial layer to separate the luminescent particles from the substrate;
Removing etching damage of the luminescent particles by adopting chemical treatment, and regulating and controlling the surface morphology of the luminescent particles;
providing a light-transmitting polymer solution, dispersing the luminescent particles in the polymer solution, and curing to form a color conversion layer.
2. The method of producing a color conversion layer for luminescent particles according to claim 1, wherein the chemical composition of the luminescent layer is Al mInnGa1-m-n N or Al mInnGa1-m-n P or Al mInnGa1-m-n As, wherein 0.ltoreq.m.ltoreq.1, 0.ltoreq.n.ltoreq.1, 0.ltoreq.1-m-n.ltoreq.1; and/or the number of the groups of groups,
The thickness of the light-emitting layer is 100 nm-500 nm.
3. The method for producing a color conversion layer for light-emitting particles according to claim 2, wherein the chemical composition ratio in the light-emitting layer is adjusted to produce light-emitting layers of different colors.
4. The method of producing a color conversion layer for luminescent particles according to claim 1, wherein the chemical composition of the sacrificial layer is Al xInyGa1-x-y N or Al xInyGa1-x-y P or Al xInyGa1-x-y As, wherein 0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, 0.ltoreq.1-x-y.ltoreq.1; and/or the number of the groups of groups,
The sacrificial layer is a heavily doped layer, the doping elements comprise silicon or germanium, and the doping concentration is not less than 5E18cm -3; and/or the number of the groups of groups,
The thickness of the sacrificial layer ranges from 100nm to 500nm.
5. The method of claim 1, wherein the chemically treated reagent comprises one or more of tetramethylammonium hydroxide, potassium hydroxide, ammonia, phosphoric acid, hydrochloric acid, hydrobromic acid, nitric acid, concentrated sulfuric acid, hydrogen peroxide, and ethylene glycol.
6. A color conversion layer prepared by the method of preparing a luminescent particle color conversion layer according to any one of claims 1 to 5.
7. A light emitting device, comprising:
The blue light or ultraviolet Micro LED chip comprises a plurality of luminous pixel units arranged in an array;
the light resistance layer is arranged on the light emitting surface of the blue light or ultraviolet Micro LED chip, a plurality of windows are arranged on the light resistance layer in a penetrating mode, and the windows expose the luminous pixel units;
the color conversion layer of claim 6 disposed on a light emitting pixel cell within the window.
8. A light-emitting device according to claim 7, wherein the light emitted by the luminescent particles in the color conversion layer on several of the light-emitting pixel units is all the same, or partially the same, or is all different.
9. The light-emitting device according to claim 7, wherein the material of the photoresist layer is an opaque material including black photoresist or black epoxy.
10. A method of fabricating a light emitting device, comprising:
providing a substrate, and growing a sacrificial layer on the surface of the substrate;
Growing a light-emitting layer on the surface of the sacrificial layer;
etching the light-emitting layer until the sacrificial layer is exposed, so that the light-emitting layer forms a plurality of light-emitting particles;
Etching the sacrificial layer to separate the luminescent particles from the substrate;
Removing etching damage of the luminescent particles by adopting chemical treatment, and regulating and controlling the surface morphology of the luminescent particles;
providing a light-transmitting polymer solution, and dispersing the luminescent particles in the polymer solution;
Providing a blue light or ultraviolet Micro LED chip, wherein the blue light or ultraviolet Micro LED chip comprises a plurality of luminous pixel units arranged in an array;
Forming a photoresist layer on the light emitting surface of the blue light or ultraviolet Micro LED chip, wherein a plurality of through windows are formed on the photoresist layer, and the windows expose the luminous pixel units;
And respectively coating the polymer solution containing the luminescent particles on the luminescent pixel units in the window and curing.
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