Light emitting device, method of manufacturing the same, and light emitting substrate

Abstract

The application provides a light-emitting device and a preparation method therefor, and a light-emitting substrate, and relates to the technical field of display. The light-emitting device comprises a substrate and an epitaxial structure located on one side of the substrate. The epitaxial structure comprises a first semiconductor layer, a quantum well layer and a second semiconductor layer arranged in sequence in a direction away from the substrate. The epitaxial structure further comprises a color conversion layer. The color conversion layer is located between the quantum well layer and the first semiconductor layer. The color conversion layer and the first semiconductor layer both comprise a first semiconductor material. A plurality of pore structures are arranged in the color conversion layer, and a quantum dot material is arranged in the pore structures. The light-emitting device has high light-emitting efficiency and good display effect.

Description

Technical Field

[0001] This application relates to the field of display, and more particularly to a light-emitting device, its fabrication method, and a light-emitting substrate. Background Technology

[0002] With the rapid development of display technology, Mini LED (Mini Light Emitting Diode) and Micro LED (Micro Light Emitting Diode) display products have attracted widespread attention. However, the luminous efficiency of these two types of LED chips in related technologies is difficult to further improve. Summary of the Invention

[0003] This application provides a light-emitting device, its fabrication method, and a light-emitting substrate. The light-emitting device has a simple structure and high luminous efficiency.

[0004] The embodiments of this application adopt the following technical solutions:

[0005] In a first aspect, embodiments of this application provide a light-emitting device, the light-emitting device including a substrate and an epitaxial structure located on one side of the substrate;

[0006] The epitaxial structure includes a first semiconductor layer, a quantum well layer, and a second semiconductor layer sequentially disposed along a direction away from the substrate;

[0007] The epitaxial structure further includes a color conversion layer located between the quantum well layer and the first semiconductor layer. Both the color conversion layer and the first semiconductor layer include a first semiconductor material. The color conversion layer has multiple pore structures, and quantum dot materials are disposed in the pore structures.

[0008] In some light-emitting devices provided in the embodiments of this application, the conductivity of the first semiconductor material in the color conversion layer is greater than the conductivity of the first semiconductor layer.

[0009] In some light-emitting devices provided in the embodiments of this application, the epitaxial structure further includes a first protective layer and a second protective layer, wherein the first protective layer is located between the first semiconductor layer and the color conversion layer, and the second protective layer is located between the quantum well layer and the color conversion layer.

[0010] In some light-emitting devices provided in the embodiments of this application, the materials of the first protective layer and the second protective layer are both the first semiconductor material, and the conductivity of the first protective layer and the second protective layer is less than the conductivity of the first semiconductor material in the color conversion layer.

[0011] In some light-emitting devices provided in the embodiments of this application, the conductivity of the first semiconductor layer is greater than the conductivity of the first protective layer.

[0012] In some light-emitting devices provided in the embodiments of this application, the distance between the surface of the second protective layer away from the quantum well layer and the quantum well layer is less than the distance between the surface of the second semiconductor layer away from the quantum well layer and the quantum well layer.

[0013] In some light-emitting devices provided in the embodiments of this application, the light-emitting device further includes a buffer layer and a conductive layer, the buffer layer being located between the substrate and the first semiconductor, and the conductive layer being located on the side of the epitaxial structure away from the substrate.

[0014] In some light-emitting devices provided in the embodiments of this application, the epitaxial structure includes a first opening, which penetrates the conductive layer, the second semiconductor layer, the quantum well layer, and the color conversion layer, and exposes the first semiconductor layer.

[0015] The light-emitting device further includes a passivation layer, a first electrode, and a second electrode. The passivation layer covers the conductive layer and the sidewall of the first opening. The passivation layer includes a second opening and a third opening. The orthographic projection of the outer contour of the third opening on the substrate overlaps with the orthographic projection of the outer contour of the first opening on the substrate. The orthographic projection of the outer contour of the second opening on the substrate overlaps with the orthographic projection of the conductive layer on the substrate.

[0016] The first electrode is electrically connected to the conductive layer through the second opening, and the second electrode is electrically connected to the first semiconductor layer through the third opening.

[0017] Secondly, embodiments of this application provide a light-emitting substrate, the light-emitting substrate including the light-emitting device as described in any one of the first aspects.

[0018] Thirdly, embodiments of this application provide a method for fabricating a light-emitting device, applicable to the fabrication of a light-emitting device as described in any one of the first aspects, the method comprising:

[0019] Provide substrate;

[0020] A first semiconductor layer, a color conversion thin film, a quantum well layer, and a second semiconductor layer are sequentially formed on the substrate.

[0021] A via is formed in the quantum well layer and the second semiconductor layer;

[0022] An electrochemical reaction is used to etch the color conversion film through the through-holes to obtain a color conversion layer with multiple pore structures, wherein quantum dot materials are disposed in the pore structures.

[0023] The electrochemical reaction solution includes an alkaline solution and quantum dot materials dispersed in the alkaline solution.

[0024] This application provides a light-emitting device and a method for fabricating the same, including a light-emitting substrate. The light-emitting device includes a substrate and an epitaxial structure located on one side of the substrate. The epitaxial structure includes a first semiconductor layer, a quantum well layer, and a second semiconductor layer sequentially disposed along a direction away from the substrate. The epitaxial structure further includes a color conversion layer located between the quantum well layer and the first semiconductor layer. Both the color conversion layer and the first semiconductor layer include a first semiconductor material. The color conversion layer has a plurality of pore structures, and quantum dot materials are disposed in the pore structures.

[0025] In the embodiments of this application, a color conversion layer is disposed in the epitaxial structure, and the color conversion layer is located between the quantum well layer and the first semiconductor layer. Both the color conversion layer and the first semiconductor layer include a first semiconductor material. The color conversion layer has multiple pore structures, and quantum dot material is disposed in the pore structures. In this way, on the one hand, since the quantum dot material is disposed in multiple pore structures, the reflection effect of the inner wall of the pore structure will make the quantum dot material have a high absorption and emission effect. On the other hand, the color conversion layer and the quantum well layer are disposed close to each other, and the distance between the quantum dot material in the pore structure of the color conversion layer and the quantum well layer is relatively small, which increases the probability of the resonant energy transfer effect between the quantum dot material and the quantum well layer. Under the combined effect of these two aspects, the color conversion efficiency of the quantum dot material in the light-emitting device can be significantly improved, thereby improving the light extraction efficiency of the light-emitting device.

[0026] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1A and Figure 1B Schematic diagrams of two light-emitting devices provided for embodiments of this application;

[0029] Figures 2-6 This application provides a schematic diagram of an intermediate structure for a method of fabricating a light-emitting device.

[0030] Figure 7 for Figure 1A and Figure 1B A schematic diagram of the color conversion layer in the image. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this application. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific feature, structure, material, or characteristic may be included in any suitable manner in any one or more embodiments or examples.

[0033] In the embodiments of this application, the use of terms such as "first" and "second" to describe the same or similar items with essentially the same function and effect is only for the purpose of clearly describing the technical solution of the embodiments of this application, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0034] The features such as "parallel," "perpendicular," and "identical" used in the embodiments of this application include features in the strict sense of "parallel," "perpendicular," and "identical," as well as cases where "approximately parallel," "approximately perpendicular," and "approximately identical" include a certain degree of error. Taking into account measurement and errors associated with the measurement of a specific quantity (e.g., limitations of the measurement system), they represent the acceptable deviation range for a specific value as determined by a person skilled in the art. For example, "approximately" can mean within one or more standard deviations, or within 10% or 5% of said value. "At least one" refers to one or more, and "more than one" refers to at least two.

[0035] In this application, "same layer" refers to the relationship between multiple film layers formed from the same material after undergoing the same step (e.g., a patterning process). "Same layer" here does not always mean that multiple film layers have the same thickness or the same height in a cross-sectional view. The polygons used in this specification are not strictly defined; they can be approximate triangles, parallelograms, trapezoids, pentagons, or hexagons, and may have minor deformations due to tolerances.

[0036] In this specification, "electrical connection" and "coupling" include situations where components are connected together by elements that have some electrical function. There are no particular limitations on what constitutes an "electrical function," as long as it allows for the transmission and reception of electrical signals between the connected components. Examples of "electrical functions" include not only electrodes and wiring, but also switching elements such as transistors, resistors, inductors, capacitors, and other components with various functions.

[0037] With the rapid development of display technology, Mini LED (Mini Light Emitting Diode) and Micro LED (Micro Light Emitting Diode) display products have attracted widespread attention. However, in these technologies, the luminous efficiency of these two types of LED chips is not high, and it further decreases after a color conversion layer is added.

[0038] Based on this, embodiments of this application provide a light-emitting device and a method for fabricating the same, including a light-emitting substrate. The light-emitting device includes a substrate and an epitaxial structure located on one side of the substrate. The epitaxial structure includes a first semiconductor layer, a quantum well layer, and a second semiconductor layer sequentially disposed along a direction away from the substrate. The epitaxial structure further includes a color conversion layer located between the quantum well layer and the first semiconductor layer. Both the color conversion layer and the first semiconductor layer include a first semiconductor material. The color conversion layer has a plurality of pore structures, and quantum dot materials are disposed in the pore structures.

[0039] The light-emitting device and its fabrication method, as well as the light-emitting substrate, provided in the embodiments of this application are described and explained in detail below with reference to the accompanying drawings.

[0040] Embodiments of this application provide a light-emitting device, such as... Figure 1A As shown, the light-emitting device includes a substrate 1 and an epitaxial structure 3 located on one side of the substrate 1;

[0041] The epitaxial structure 3 includes a first semiconductor layer 31, a quantum well layer 35, and a second semiconductor layer 36 sequentially disposed along a direction away from the substrate 1;

[0042] The epitaxial structure 3 further includes a color conversion layer 33, which is located between the quantum well layer 35 and the first semiconductor layer 31. Both the color conversion layer 33 and the first semiconductor layer 31 comprise a first semiconductor material. Figure 7 As shown, the color conversion layer 33 has multiple porous structures KX, and quantum dot material QD is disposed in the porous structures KX.

[0043] The light-emitting devices provided in the embodiments of this application can be structures with dimensions miniaturized to the scale of hundreds of micrometers. For example, the area of ​​the light-emitting region of the light-emitting device is preferably 1 mm². 2 Below, 10000μm is more preferred. 2 Hereinafter, 3000μm is further preferred. 2 Hereinafter, 700μm is further preferred. 2 Below that, it can even be at 200μm 2 the following.

[0044] The specific material of the substrate 1 described above is not limited here. For example, the material of the substrate 1 may include one of glass, silicon, sapphire, and polyimide.

[0045] In some embodiments, the light-emitting device may not include the substrate 1. Specifically, the substrate 1, which is made of sapphire, can be removed by laser lift-off; the substrate 1, which is made of silicon, can be removed by wet etching or dry etching. Of course, in some embodiments, the light-emitting device may include the substrate 1.

[0046] The first semiconductor layer 31 can be a P-type semiconductor layer, such as P-type gallium nitride (P-GaN), and the second semiconductor layer 36 can be an N-type semiconductor layer, such as N-type gallium nitride (N-GaN). Alternatively, the first semiconductor layer 31 can be an N-type semiconductor layer, such as N-type gallium nitride (N-GaN), and the second semiconductor layer 36 can be a P-type semiconductor layer, such as P-type gallium nitride (P-GaN).

[0047] This specification describes and explains the example where the first semiconductor layer 31 can be an N-type semiconductor layer, such as N-type gallium nitride (N-GaN), and the second semiconductor layer 36 can be a P-type semiconductor layer, such as P-type gallium nitride (P-GaN).

[0048] Combination Figure 7 As shown, both the color conversion layer 33 and the first semiconductor layer 31 include a first semiconductor material. The color conversion layer 33 is provided with a plurality of pore structures KX, and quantum dot material QD is provided in the pore structures KX.

[0049] For example, the substrate material of the color conversion layer 33 is a first semiconductor material, in which a plurality of pore structures KX are provided, and quantum dot material QD is contained in the pore structures KX.

[0050] For example, the pore structure KX is a nanoscale cavity structure with a size larger than that of a quantum dot (QD).

[0051] For example, the size of the pore structure KX is greater than or equal to 20 nm and less than or equal to 300 nm.

[0052] For example, the thickness of the color conversion layer 33 can be in the range of 300nm to 500nm.

[0053] For example, the size range of quantum dot (QD) can be 8–10 nm.

[0054] For example, the shape of a quantum dot (QD) may include a sphere or an ellipsoid.

[0055] For example, the quantum dot material (QD) can be a green quantum dot material or a red quantum dot material.

[0056] For example, quantum dot materials may include CdZnSe / ZnS quantum dots, which are nanostructures composed of two materials, cadmium zinc selenide (CdZnSe) and zinc sulfide (ZnS), and they typically exist in nanoscale spherical or columnar structures.

[0057] For example, CdZnSe / ZnS quantum dots can be a "core-shell structure" with CdZnSe / ZnS material as the core and a polymer as the outer shell. For example, the polymer on the outer shell can be poly(isobutylene-maleic anhydride).

[0058] In the embodiments of this application, such as Figure 1A As shown, by setting a color conversion layer 33 in the epitaxial structure 3, and positioning the color conversion layer 33 between the quantum well layer 35 and the first semiconductor layer 31, both the color conversion layer 33 and the first semiconductor layer 31 include a first semiconductor material. The color conversion layer 33 contains multiple pore structures KX, and quantum dot material QD is disposed within each of the pore structures KX. In this way, on the one hand, since the quantum dot material QD is disposed within multiple pore structures KX, the reflection effect of the inner walls of these pore structures KX results in the quantum dot material QD exhibiting high light absorption and emission effects. On the other hand, the color conversion layer 33 is positioned close to the quantum well layer 35, and the distance between the quantum dot material in the pore structures of the color conversion layer and the quantum well layer is relatively short, increasing the probability of resonant energy transfer (FRET) between the quantum dot material and the quantum well layer. Under the combined effect of these two aspects, the color conversion efficiency of the quantum dot material in the light-emitting device can be significantly improved, thereby increasing the light extraction efficiency of the light-emitting device.

[0059] In some light-emitting devices provided in the embodiments of this application, such as Figure 1A As shown, the conductivity of the first semiconductor material in the color conversion layer 33 is greater than that of the first semiconductor layer 31.

[0060] For example, the first semiconductor material can be N-type gallium nitride (N-GaN), and the second semiconductor material can be P-type gallium nitride (P-GaN).

[0061] For example, the first semiconductor material in the color conversion layer 33 can be heavily doped N-type gallium nitride (N-GaN), and the first semiconductor material in the first semiconductor layer 31 can be moderately doped N-type gallium nitride (N-GaN).

[0062] For example, the doping concentration of the first semiconductor material in the color conversion layer 33 can be 1.8*10⁻⁶. 19 ~2*10 19 / cm 3 .

[0063] For example, the doping concentration of the first semiconductor material in the first semiconductor layer 31 can be 5*10. 18 ~6*10 18 / cm 3 .

[0064] Among them, the higher the doping concentration, the higher the conductivity. During the preparation of the color conversion layer 33, an electrochemical corrosion reaction occurs according to the conductivity, that is, the film layer and material with high conductivity are corroded first.

[0065] In some light-emitting devices provided in the embodiments of this application, such as Figure 1B As shown, the epitaxial structure 3 also includes a first protective layer 32 and a second protective layer 34. The first protective layer 32 is located between the first semiconductor layer 31 and the color conversion layer 33, and the second protective layer 34 is located between the quantum well layer 35 and the color conversion layer 33.

[0066] For example, during the fabrication process, the first protective layer 32 is used to protect the first semiconductor layer 31 from electrochemical corrosion, and the second protective layer 34 is used to protect the quantum well layer 35 from electrochemical corrosion.

[0067] In some light-emitting devices provided in the embodiments of this application, the materials of the first protective layer 32 and the second protective layer 34 are both first semiconductor materials, for example, the materials of the first protective layer 32 and the second protective layer 34 are both N-type gallium nitride (N-GaN).

[0068] The conductivity of the first protective layer 32 and the second protective layer 34 is lower than that of the first semiconductor material in the color conversion layer 33.

[0069] In the embodiments of this application, since the higher the conductivity, the earlier the porous structure KX in the color conversion layer 33 is prepared by electrochemical reaction, the earlier it will be corroded to form a porous structure, in the preparation process, the conductivity of the first protective layer 32 and the second protective layer 34 is set to be less than the conductivity of the first semiconductor material in the color conversion layer 33. In this way, the first protective layer 32 can be used to protect the first semiconductor layer 31 from electrochemical corrosion, and the second protective layer 34 can be used to protect the quantum well layer 35 from electrochemical corrosion.

[0070] For example, the materials of the first protective layer 32 and the second protective layer 34 can both be lightly doped N-type gallium nitride (N-GaN).

[0071] For example, the doping concentration of the first semiconductor material in the first protective layer 32 and the second protective layer 34 can be 0.1*10. 18 ~0.5*10 18 / cm 3 .

[0072] For example, the doping concentration of the first semiconductor material in the first protective layer 32 and the second protective layer 34 can be equal.

[0073] In the embodiments of this application, the thickness h1 of the second protective layer 34 is less than the thickness h2 of the second semiconductor layer 36.

[0074] For example, the thickness h3 of the first protective layer 32 and the thickness h1 of the second protective layer 34 can be equal.

[0075] For example, the thickness h3 of the first protective layer 32 and the thickness h1 of the second protective layer 34 can both be in the range of 50nm to 80nm.

[0076] For example, the thickness h2 of the second semiconductor layer 36 is greater than or equal to 100 nm.

[0077] In the embodiments of this application, since the materials of the first protective layer 32 and the second protective layer 34 are both first semiconductor materials, while the second protective layer 34 protects the quantum well layer 35, the thickness h1 of the second protective layer 34 is set to be less than the thickness h2 of the second semiconductor layer 36. Thus, when the color conversion layer 33 is disposed on the side of the second protective layer 34 away from the quantum well layer 35, compared to disposing the color conversion layer 33 on the side of the second semiconductor layer 36 away from the quantum well layer 35, the color conversion layer 33 is closer to the quantum well layer 35. The quantum dot material QD in the pore structure KX of the color conversion layer is closer to the quantum well layer 35, and the probability of a resonant energy transfer effect between the quantum dot material QD and the quantum well layer 35 increases. This can further improve the color conversion efficiency of the quantum dot material in the light-emitting device, thereby improving the light extraction efficiency of the light-emitting device.

[0078] In some light-emitting devices provided in the embodiments of this application, such as Figure 1B As shown, the conductivity of the first semiconductor layer 31 is greater than that of the first protective layer 32.

[0079] For example, the materials of the first protective layer 32 and the second protective layer 34 can both be lightly doped N-type gallium nitride (N-GaN). For instance, the doping concentration of the first semiconductor material in the first protective layer 32 and the second protective layer 34 can be 0.1*10⁻⁶. 18 ~0.5*10 18 / cm 3 .

[0080] For example, the first semiconductor material in the first semiconductor layer 31 can be moderately doped N-type gallium nitride (N-GaN). For instance, the doping concentration of the first semiconductor material in the first semiconductor layer 31 can be 5*10⁻⁶. 18 ~6*10 18 / cm 3 .

[0081] Doping the first semiconductor material in the first semiconductor layer 31 can improve the uniformity of current distribution. In addition, it is also beneficial to the uniform etching during the subsequent fabrication of the second electrode 7.

[0082] For example, the thickness of the first semiconductor layer 31 can be in the range of 1.5 μm to 2 μm.

[0083] The higher the doping concentration, the higher the conductivity.

[0084] In the embodiments of this application, by setting the conductivity of the first semiconductor layer 31 to be greater than that of the first protective layer 32, the first semiconductor layer 31 and the electrode will have better conductivity when the electrode (e.g., the negative electrode) is subsequently set.

[0085] In some light-emitting devices provided in the embodiments of this application, such as Figure 1B As shown, the distance h1 between the surface of the second protective layer 34 away from the quantum well layer 35 and the quantum well layer 35 is less than the distance h2 between the surface of the second semiconductor layer 36 away from the quantum well layer 35 and the quantum well layer 35.

[0086] In some light-emitting devices provided in the embodiments of this application, such as Figure 1A and Figure 1B As shown, the light-emitting device also includes a buffer layer 2 and a conductive layer 4. The buffer layer 2 is located between the substrate 1 and the first semiconductor 31, and the conductive layer 4 is located on the side of the epitaxial structure 3 away from the substrate 1.

[0087] For example, the material of the buffer layer 2 can be a first semiconductor material, and the buffer layer 2 can be used to improve the film integrity and adhesion of the epitaxial structure 3 during epitaxial growth.

[0088] For example, the material of the conductive layer 4 can be a light-transmitting and conductive material, such as indium tin oxide (ITO). The conductive layer 4 is used to improve the contact between the subsequent electrode (e.g., the anode) and the second semiconductor layer 36, thereby improving current transmission performance.

[0089] For example, the thickness of the buffer layer 2 can range from 1 μm to 2 μm.

[0090] For example, the thickness of the conductive layer 4 can be in the range of 100nm ± 10nm.

[0091] In some light-emitting devices provided in the embodiments of this application, such as Figure 1A , Figure 1B and combined Figure 5 As indicated by the markings, the epitaxial structure 3 includes a first opening K1, which penetrates the conductive layer 4, the second semiconductor layer 36, the quantum well layer 35, the color conversion layer 33, and exposes the first semiconductor layer 31.

[0092] Combination Figure 6 As indicated by the markings, the light-emitting device also includes a passivation layer 5, a first electrode, and a second electrode. The passivation layer 5 covers the sidewalls of the conductive layer 4 and the first opening K1. The passivation layer 5 includes a second opening K2 and a third opening K3. The orthographic projection of the outer contour of the third opening K3 on the substrate 1 overlaps with the orthographic projection of the outer contour of the first opening K1 on the substrate 1. The orthographic projection of the outer contour of the second opening K2 on the substrate 1 overlaps with the orthographic projection of the conductive layer 4 on the substrate.

[0093] The first electrode 6 is electrically connected to the conductive layer 4 through the second opening K2, and the second electrode 7 is electrically connected to the first semiconductor layer 31 through the third opening K3.

[0094] Embodiments of this application provide a light-emitting substrate, which includes a light-emitting device as described above.

[0095] For example, the light-emitting substrate described above also includes a driving substrate, which is electrically connected to a plurality of light-emitting devices.

[0096] In some examples, the light-emitting substrate described above can be used directly for backlighting. For example, multiple light-emitting devices in the light-emitting substrate emit the same color and are all white; or multiple light-emitting devices in the light-emitting substrate emit the same color and are all blue.

[0097] In some examples, the light-emitting substrate described above can be used directly for display. For example, the light-emitting substrate may contain multiple light-emitting devices with different light-emitting colors, such as three light-emitting devices that emit red, green and blue light at the same time.

[0098] In the light-emitting substrate provided in the embodiments of this application, a color conversion layer 33 is provided in the epitaxial structure 3, and the color conversion layer 33 is located between the quantum well layer 35 and the first semiconductor layer 31. Both the color conversion layer 33 and the first semiconductor layer 31 include a first semiconductor material. The color conversion layer 33 is provided with a plurality of pore structures KX, and quantum dot material QD is provided in the pore structures KX. In this way, on the one hand, since the quantum dot material QD is provided in the plurality of pore structures KX, the reflection effect of the inner wall of the pore structures KX will make the quantum dot material QD have a high light absorption and emission effect. On the other hand, the color conversion layer 33 and the quantum well layer 35 are arranged close to each other, and the quantum dot material in the pore structure of the color conversion layer is close to the quantum well layer, increasing the probability of resonant energy transfer effect between the quantum dot material and the quantum well layer. Under the combined effect of these two aspects, the color conversion efficiency of the quantum dot material in the light-emitting device can be significantly improved, thereby improving the light extraction efficiency of the light-emitting device.

[0099] Embodiments of this application provide a method for fabricating a light-emitting device, applicable to the fabrication of any of the light-emitting devices described above, the method comprising:

[0100] S01, providing such Figure 2 Substrate 1 shown;

[0101] The specific material of the substrate 1 described above is not limited here. For example, the material of the substrate 1 may include one of glass, silicon, sapphire, and polyimide.

[0102] In some embodiments, the light-emitting device may not include the substrate 1. Specifically, the substrate 1, which is made of sapphire, can be removed by laser lift-off; the substrate 1, which is made of silicon, can be removed by wet etching or dry etching. Of course, in some embodiments, the light-emitting device may include the substrate 1.

[0103] S02, such as Figure 2 As shown, a first semiconductor layer 31, a color conversion thin film 33', a quantum well layer 35, and a second semiconductor layer 36 are sequentially formed on the substrate 1.

[0104] Among them, the color conversion film 33' is the structure of the color conversion layer 33 before it is electrochemically corroded.

[0105] S03, such as Figure 4 As shown, a via Via is formed in the quantum well layer 35 and the second semiconductor layer 36;

[0106] The aforementioned via Via is an intermediate structure in the preparation process, designed to expose a portion of the color conversion film 33' so that it can directly contact the electrochemical reaction solution. The electrochemical reaction solution is also known as the electrolyte.

[0107] S04. An electrochemical reaction is used to etch the color conversion film 33' through the through-hole Via to obtain a color conversion layer 33 with multiple pore structures KX, in which quantum dot material QD is disposed;

[0108] The electrochemical reaction solution includes an alkaline solution and quantum dot materials dispersed in the alkaline solution.

[0109] Electrochemical corrosion is a process in which a metal and an electrolyte form two electrodes, creating a corrosion galvanic cell. For example, iron and oxygen. Because the electrode potential of iron is always lower than that of oxygen, iron is the negative electrode and is thus corroded.

[0110] In the embodiments of this application, the light-emitting device is placed in a reaction cell, the color conversion film 33' is the anode, and the platinum electrode (Pt) is the cathode. By setting the voltage and the reaction time of the electrochemical corrosion reaction, a porous structure KX is formed in the color conversion film 33' during the etching process of the color conversion film 33' in the electrolyte. Since the electrochemical reaction liquid includes quantum dot materials dispersed in an alkaline solution, the quantum dot materials enter the porous structure with the corrosion reaction, and a color conversion layer 33 with multiple porous structures KX can be obtained, and quantum dot materials QD are disposed in the porous structure KX.

[0111] It should be noted that, to avoid ambiguity, the accompanying drawings in this application are only shown on [specific locations]. Figure 7 The quantum dot material QD is depicted in the porous structure KX. The quantum dot material QD in other figures is omitted. For the detailed structure of the quantum dot material QD in the porous structure KX, please refer to [reference needed]. Figure 7 The illustration is shown in the image.

[0112] In the fabrication method of the light-emitting device provided in the embodiments of this application, a color conversion layer 33 is provided in the epitaxial structure 3, and the color conversion layer 33 is located between the quantum well layer 35 and the first semiconductor layer 31. Both the color conversion layer 33 and the first semiconductor layer 31 include a first semiconductor material. The color conversion layer 33 is provided with multiple pore structures KX, and quantum dot material QD is provided in the pore structures KX. In this way, on the one hand, since the quantum dot material QD is provided in multiple pore structures KX, the reflection effect of the inner wall of the pore structure KX will make the quantum dot material QD have a high light absorption and emission effect. On the other hand, the color conversion layer 33 and the quantum well layer 35 are arranged close to each other, and the distance between the quantum dot material in the pore structure of the color conversion layer and the quantum well layer is relatively small, which increases the probability of the resonant energy transfer effect between the quantum dot material and the quantum well layer. Under the combined effect of these two aspects, the color conversion efficiency of the quantum dot material in the light-emitting device can be significantly improved, thereby improving the light extraction efficiency of the light-emitting device.

[0113] The following is based on Figure 1B Taking the structure shown as an example, the fabrication method of this light-emitting device will be explained in detail:

[0114] 1. For example Figure 2 As shown, a substrate 1 is provided, such as a sapphire substrate; a buffer layer 2, a first semiconductor layer 31, a first protective layer 32, a color conversion thin film 33', a second protective layer 34, a quantum well layer 35, and a second semiconductor layer 36 are epitaxially grown sequentially on the substrate 1.

[0115] 2. For example Figure 3 As shown, conductive layer 4 is formed;

[0116] The conductive layer 4 can enhance the contact between the subsequent first electrode and the second semiconductor layer 36 (e.g., P-GaN), which is beneficial for current transmission;

[0117] 3. Via etching: Specifically, the conductive layer 4, the second semiconductor layer 36, the quantum well layer 35, and the second protective layer 34 are etched sequentially, exposing the color conversion film 33'.

[0118] It should be noted that, when etching the via Via, in some examples, the second protective layer 34 can be etched without etching the color conversion film 33'; in other examples, the second protective layer 34 can be etched while only part of the color conversion film 33' is etched, in order to avoid the second protective layer 34 remaining and reducing the efficiency of the electrochemical reaction.

[0119] For example, the planar shape of the via can be rectangular, for instance, its size can be 100μm*60μm, and its depth can be 1μm.

[0120] 4. Prepare the electrochemical reaction solution;

[0121] In practical applications, both acidic and alkaline solutions can be used as electrochemical reaction solutions. However, since quantum dot materials (QD) tend to agglomerate in acidic solutions, alkaline solutions are used as electrolytes.

[0122] For example, the electrolyte is an alkaline solution in which quantum dot (QD) materials are dispersed;

[0123] For example, the alkaline solution can be a KOH solution with a concentration of 2 ± 0.5%.

[0124] For example, the concentration of quantum dot material QD in the solution is 10 ± 1 mg / ml.

[0125] For example, the shape of a quantum dot (QD) may include a sphere or an ellipsoid.

[0126] For example, the quantum dot material (QD) can be either green or red. The emission peak wavelength of green quantum dot materials is around 530 nm, while that of red quantum dot materials is around 625 nm.

[0127] For example, quantum dot materials may include CdZnSe / ZnS quantum dots, which are nanostructures composed of two materials, cadmium zinc selenide (CdZnSe) and zinc sulfide (ZnS), and they typically exist in nanoscale spherical or columnar structures.

[0128] For example, CdZnSe / ZnS quantum dots can be a "core-shell structure" with CdZnSe / ZnS material as the core and a polymer as the outer shell. For example, the polymer on the outer shell can be poly(isobutylene-maleic anhydride).

[0129] 5. Place the sample into the reaction cell, add a chemical reaction solution to the reaction cell, apply voltage, and carry out an electrochemical corrosion reaction (ECE) to etch the color conversion film 33', thereby obtaining the color conversion layer 33;

[0130] In this process, the color conversion film 33' serves as the anode for the electrochemical corrosion reaction, and platinum (Pt) serves as the cathode. The applied voltage can be 15V.

[0131] For example, the substrate material of the color conversion layer 33 is a first semiconductor material, in which a plurality of pore structures KX are provided, and quantum dot material QD is contained in the pore structures KX.

[0132] For example, the porosity of the pore structure KX in the color conversion layer 33 can reach 70% ± 3%.

[0133] 6. For example Figure 5As shown, based on the via Via, the color conversion layer 33 and the second protective layer 32 are further etched to obtain the first opening K1;

[0134] In the next step, the etching can be performed down to the second protective layer 32 without etching the first semiconductor layer 31; or, the etching can be performed down to the second protective layer 32 while the first semiconductor layer 31 is slightly etched to avoid leaving the second protective layer 32, thereby improving the conductivity between the first semiconductor layer 31 and the electrode.

[0135] In addition, etching the color conversion layer 33 and the second protective layer 32 can remove the color conversion layer 33 below the via Via, thereby ensuring that the color conversion layer 33 and the quantum well layer 35 overlap on the substrate and avoid the presence of quantum dot material in areas other than below the quantum well layer 35.

[0136] In practical applications, SEM (Scanning Electron Microscope) and TEM (Transmission Electron Microscope) can be used to test and determine the etching state and QD doping morphology, while EDX (Energy Dispersive X-ray Spectroscopy) can be used to detect QD composition to determine its doping status.

[0137] 7. For example Figure 6 As shown, a passivation layer 5 is formed, and a second opening K2 and a third opening K3 are formed on the passivation layer 5; a first electrode 6 is formed on the second opening K2, and a second electrode 7 is formed on the third opening K3.

[0138] In this process, the passivation layer 5 covers the sidewalls of the conductive layer 4 and the first opening K1, the orthographic projection of the outer contour of the third opening K3 on the substrate 1 overlaps with the orthographic projection of the outer contour of the first opening K1 on the substrate 1, and the orthographic projection of the outer contour of the second opening K2 on the substrate 1 overlaps with the orthographic projection of the conductive layer 4 on the substrate; the first electrode 6 is electrically connected to the conductive layer 4 through the second opening K2, and the second electrode 7 is electrically connected to the first semiconductor layer 31 through the third opening K3.

[0139] For example, the first electrode 6 and the second electrode 7 can both adopt a Ti / Al / Ni / Au or Cr / Pt / Au stacked structure with an overall thickness of about 1.5 μm.

[0140] This specification only describes the structure and fabrication process related to the inventive point of the light-emitting device. The light-emitting device may also include other films and structures, and the fabrication method may also include other processes and steps. For details, please refer to the descriptions in related technologies, which will not be repeated here.

[0141] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A light-emitting device, characterized in that, The light-emitting device includes a substrate and an epitaxial structure located on one side of the substrate; The epitaxial structure includes a first semiconductor layer, a quantum well layer, and a second semiconductor layer sequentially disposed along a direction away from the substrate; The epitaxial structure further includes a color conversion layer located between the quantum well layer and the first semiconductor layer. Both the color conversion layer and the first semiconductor layer include a first semiconductor material. The color conversion layer has multiple pore structures, and quantum dot materials are disposed in the pore structures.

2. The light-emitting device according to claim 1, characterized in that, The conductivity of the first semiconductor material in the color conversion layer is greater than the conductivity of the first semiconductor layer.

3. The light-emitting device according to claim 2, characterized in that, The epitaxial structure further includes a first protective layer and a second protective layer, wherein the first protective layer is located between the first semiconductor layer and the color conversion layer, and the second protective layer is located between the quantum well layer and the color conversion layer.

4. The light-emitting device according to claim 3, characterized in that, Both the first protective layer and the second protective layer are made of the first semiconductor material, and the conductivity of both the first protective layer and the second protective layer is less than the conductivity of the first semiconductor material in the color conversion layer.

5. The light-emitting device according to claim 3, characterized in that, The conductivity of the first semiconductor layer is greater than that of the first protective layer.

6. The light-emitting device according to claim 4 or 5, characterized in that, The distance between the surface of the second protective layer away from the quantum well layer and the quantum well layer is less than the distance between the surface of the second semiconductor layer away from the quantum well layer and the quantum well layer.

7. The light-emitting device according to any one of claims 1 to 5, characterized in that, The light-emitting device further includes a buffer layer and a conductive layer, the buffer layer being located between the substrate and the first semiconductor, and the conductive layer being located on the side of the epitaxial structure away from the substrate.

8. The light-emitting device according to claim 7, characterized in that, The epitaxial structure includes a first opening that penetrates the conductive layer, the second semiconductor layer, the quantum well layer, and the color conversion layer, and exposes the first semiconductor layer. The light-emitting device further includes a passivation layer, a first electrode, and a second electrode. The passivation layer covers the conductive layer and the sidewall of the first opening. The passivation layer includes a second opening and a third opening. The orthographic projection of the outer contour of the third opening on the substrate overlaps with the orthographic projection of the outer contour of the first opening on the substrate. The orthographic projection of the outer contour of the second opening on the substrate overlaps with the orthographic projection of the conductive layer on the substrate. The first electrode is electrically connected to the conductive layer through the second opening, and the second electrode is electrically connected to the first semiconductor layer through the third opening.

9. A light-emitting substrate, characterized in that, The light-emitting substrate includes the light-emitting device as described in any one of claims 1 to 8.

10. A method for fabricating a light-emitting device, characterized in that, The method is applied to the fabrication of a light-emitting device as described in any one of claims 1 to 8, the method comprising: Provide substrate; A first semiconductor layer, a color conversion thin film, a quantum well layer, and a second semiconductor layer are sequentially formed on the substrate. A via is formed in the quantum well layer and the second semiconductor layer; An electrochemical reaction is used to etch the color conversion film through the through-holes to obtain a color conversion layer with multiple pore structures, wherein quantum dot materials are disposed in the pore structures. The electrochemical reaction solution includes an alkaline solution and quantum dot materials dispersed in the alkaline solution.

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