Display device and manufacturing method therefor, and display apparatus

Abstract

The present disclosure provides a display device and a manufacturing method therefor, and a display apparatus. The display device comprises: a substrate and a plurality of light-emitting elements arranged on the substrate, wherein the light-emitting elements each comprise at least two stacked nanopillar light-emitting units, each of the nanopillar light-emitting units comprises a quantum well film layer made of the same material, diameters of quantum well film layers in the at least two nanopillar light-emitting units sequentially decrease in a direction away from the substrate, and the at least two nanopillar light-emitting units have different light emission colors.

Description

Display devices and their manufacturing methods, display apparatus Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a display device and its manufacturing method, and a display apparatus. Background Technology

[0002] With the continuous development of display technology, the application fields of display devices are becoming increasingly wide, and the types of display devices are also increasing. Commonly used display devices include light-emitting diode (LED) display devices. LED display devices emit light by releasing energy through the recombination of electrons and holes, which can efficiently convert electrical energy into light energy, and are widely used in lighting, flat panel displays, medical devices and other fields. Summary of the Invention

[0003] The purpose of this disclosure is to provide a display device, a method for manufacturing the same, and a display apparatus.

[0004] To achieve the above objectives, this disclosure provides the following technical solution:

[0005] A first aspect of this disclosure provides a display device, comprising: a substrate and a plurality of light-emitting elements disposed on the substrate, wherein the light-emitting elements include at least two nanopillar light-emitting units stacked thereon, each of the nanopillar light-emitting units comprising a quantum well film layer of the same material, the diameter of the quantum well film layer in the at least two nanopillar light-emitting units decreasing sequentially in a direction away from the substrate, and the at least two nanopillar light-emitting units emitting different colors.

[0006] Optionally, the nanopillar light-emitting unit further includes an N-type semiconductor layer and a P-type semiconductor layer stacked together, with the quantum well film layer located between the N-type semiconductor layer and the P-type semiconductor layer;

[0007] The light-emitting element further includes at least one tunnel junction layer. In the same light-emitting element, there is a tunnel junction layer between two adjacent nanopillar light-emitting units. The tunnel junction layer is coupled to a P-type semiconductor layer in one nanopillar light-emitting unit and an N-type semiconductor layer in another nanopillar light-emitting unit, respectively. The tunnel junction layer is used to transport charge carriers to the semiconductor layer adjacent to the side of the tunnel junction layer facing away from the substrate.

[0008] The light-emitting element further includes at least one common electrode layer, which is coupled to a semiconductor layer adjacent to the side of the corresponding tunnel junction layer facing the substrate.

[0009] Optionally, in each nanopillar light-emitting unit, the N-type semiconductor layer, the quantum well film layer, and the P-type semiconductor layer are stacked sequentially in a direction away from the substrate, and the diameters of the N-type semiconductor layer, the quantum well film layer, and the P-type semiconductor layer in the same nanopillar light-emitting unit are approximately the same;

[0010] The common electrode layer is coupled to the P-type semiconductor layer adjacent to the side of the corresponding tunnel junction layer facing the substrate.

[0011] Optionally, the plurality of light-emitting elements are divided into multiple columns of light-emitting elements, each column of light-emitting elements including a plurality of light-emitting elements arranged along the column direction;

[0012] In the same row of light-emitting elements, the common electrode layer corresponding to the same tunnel membrane layer of each light-emitting element is formed into a common electrode part of an integral structure.

[0013] Optionally, in at least two adjacent rows of light-emitting elements, the same tunneling membrane layer corresponds to the same common electrode portion.

[0014] Optionally, the common electrode portions corresponding to the same tunnel membrane layer are coupled to each other through an electrode connection portion.

[0015] Optionally, the nanopillar light-emitting unit further includes a first electrode and a second electrode, wherein the first electrode is coupled to the N-type semiconductor layer and the second electrode is coupled to the P-type semiconductor layer;

[0016] The common electrode layer is reused as: the electrode of the adjacent nanopillar light-emitting unit that is far from the substrate and the electrode of the adjacent nanopillar light-emitting unit that is far from the substrate that is close to the substrate.

[0017] Optionally, in each of the light-emitting elements, in the nanopillar light-emitting unit closest to the substrate, the semiconductor layer located between the quantum well film and the substrate is formed as an integral semiconductor film, and the electrode coupled to the integral semiconductor film is located on the side of the integral semiconductor film facing away from the substrate.

[0018] In each of the light-emitting elements, in the nanopillar light-emitting unit furthest from the substrate, the electrode coupled to the semiconductor layer furthest from the substrate is formed as an integral whole electrode film layer.

[0019] The display device further includes a first conductive pad, a second conductive pad, and at least one third conductive pad disposed on the same layer. The first conductive pad is coupled to an electrode coupled to the entire semiconductor film layer, the second conductive pad is coupled to the entire electrode film layer, and the third conductive pad is coupled to a corresponding electrode connection portion.

[0020] Optionally, in each of the light-emitting elements, in the nanopillar light-emitting unit closest to the substrate, the semiconductor layer located between the quantum well film and the substrate is formed as an integral semiconductor film, and the electrode coupled to the integral semiconductor film is located between the integral semiconductor film and the substrate.

[0021] In each of the light-emitting elements, in the nanopillar light-emitting unit furthest from the substrate, the electrode coupled to the semiconductor layer furthest from the substrate is formed as an integral whole electrode film layer.

[0022] The substrate includes an integrated circuit substrate, which includes a first pin, a second pin, and at least one third pin; the first pin is coupled to an electrode coupled to the entire semiconductor film layer.

[0023] The display device further includes a fourth conductive pad and at least one fifth conductive pad. The fourth conductive pad is coupled to the entire electrode film layer and the second pin, respectively, and the fifth conductive pad is coupled to the corresponding electrode connection portion and the corresponding third pin, respectively.

[0024] Optionally, the light-emitting element includes a first nanopillar light-emitting unit, a second nanopillar light-emitting unit, and a third nanopillar light-emitting unit stacked sequentially along a direction away from the substrate, wherein the N-type semiconductor layer, the quantum well film layer, and the P-type semiconductor layer are arranged sequentially in each nanopillar light-emitting unit;

[0025] The light-emitting element includes a first tunneling film layer and a second tunneling film layer. The first tunneling film layer is located between the P-type semiconductor layer of the first nanopillar light-emitting unit and the N-type semiconductor layer of the second nanopillar light-emitting unit. The second tunneling film layer is located between the P-type semiconductor layer of the second nanopillar light-emitting unit and the N-type semiconductor layer of the third nanopillar light-emitting unit.

[0026] The light-emitting element includes a first common electrode layer and a second common electrode layer. The first common electrode layer is coupled to a P-type semiconductor layer adjacent to the side of the corresponding first tunnel junction layer facing the substrate. The second common electrode layer is coupled to a P-type semiconductor layer adjacent to the side of the corresponding second tunnel junction layer facing the substrate.

[0027] Optionally, in the same column of light-emitting elements, the first common electrode layer corresponding to each first tunnel conjunctival layer is formed as a first common electrode portion of an integral structure; and / or, the second common electrode layer corresponding to each second tunnel conjunctival layer is formed as a second common electrode portion of an integral structure.

[0028] Optionally, in at least two adjacent rows of light-emitting elements, each first tunnel conjunctival layer corresponds to the same first common electrode portion; and / or, each second tunnel conjunctival layer corresponds to the same second common electrode portion.

[0029] Optionally, each of the first common electrode portions is coupled to each other through a first electrode connection portion; and / or, each of the second common electrode portions is coupled to each other through a second electrode connection portion;

[0030] The first common electrode portion and the second common electrode portion are alternately arranged along a first direction, and the first electrode connection portion and the second electrode connection portion are opposite each other along a second direction, the second direction intersecting the first direction.

[0031] Optionally, the N-type semiconductor layer of the nanopillar light-emitting unit closest to the substrate in each light-emitting element is formed as an integral film layer; and / or, the quantum well film layer of the nanopillar light-emitting unit closest to the substrate in each light-emitting element is formed as an integral film layer; and / or, the P-type semiconductor layer of the nanopillar light-emitting unit closest to the substrate in each light-emitting element is formed as an integral film layer.

[0032] Based on the technical solutions of the above-mentioned display devices, the second aspect of this disclosure provides a display apparatus including a plurality of the above-mentioned display devices.

[0033] Based on the above-described display device technical solution, a third aspect of this disclosure provides a method for manufacturing a display device, used to manufacture the above-described display device; the manufacturing method includes the step of fabricating a plurality of light-emitting elements on a substrate; the step of fabricating the light-emitting elements specifically includes:

[0034] The light-emitting element comprises at least two stacked nanopillar light-emitting units fabricated using epitaxial growth technology; or,

[0035] The light-emitting element is fabricated using nanoimprint lithography, comprising at least two stacked nanopillar light-emitting units. Attached Figure Description

[0036] The accompanying drawings, which are included to provide a further understanding of this disclosure and form part of this disclosure, illustrate exemplary embodiments of the present disclosure and are used to explain the disclosure, but do not constitute an undue limitation of the disclosure. In the drawings:

[0037] Figures 1 to 8 are schematic cross-sectional views of the manufacturing process of the first type of display device provided in the embodiments of this disclosure;

[0038] Figure 9 is a cross-sectional schematic diagram of a second type of display device provided in an embodiment of this disclosure;

[0039] Figure 10 is a top view schematic diagram of the manufacturing process of the first display device provided in the embodiments of this disclosure;

[0040] Figure 11 is a top view of a third type of display device provided in an embodiment of this disclosure;

[0041] Figure 12 is a schematic diagram of the first cross section along the A1A2 direction in Figure 11;

[0042] Figure 13 is a schematic diagram of the second cross section along the A1A2 direction in Figure 11. Detailed Implementation

[0043] To further illustrate the display device and its manufacturing method, as well as the display apparatus provided in the embodiments of this disclosure, a detailed description is provided below with reference to the accompanying drawings.

[0044] Compared to traditional LED display devices, nanopillar LED display devices exhibit more complete stress relaxation, effectively reducing the quantum confinement Stark effect (QCSE), improving internal quantum efficiency, and enhancing light extraction efficiency. However, in these nanopillar LED display devices, the quantum well film (MQW) materials used in different colors vary significantly, resulting in substantial differences in current density between the different MQW materials. Furthermore, the small size of nanopillar LED display devices makes electrode fabrication challenging.

[0045] Please refer to Figures 1 to 13. This disclosure provides a display device, including: a substrate 10 and a plurality of light-emitting elements 20 disposed on the substrate 10. Each light-emitting element 20 includes at least two nanopillar light-emitting units 201 (e.g., red nanopillar light-emitting unit R, green nanopillar light-emitting unit G, and blue nanopillar light-emitting unit B) stacked together. Each nanopillar light-emitting unit 201 includes a quantum well film layer 201b of the same material. The diameter of the quantum well film layer 201b in the at least two nanopillar light-emitting units 201 decreases sequentially in the direction away from the substrate 10. The at least two nanopillar light-emitting units emit different colors.

[0046] As shown in FIG10, by way of example, the display device includes a plurality of light-emitting elements 20, which are arranged in an array on the substrate 10. For example, the plurality of light-emitting elements 20 can be divided into multiple rows of light-emitting elements 20 and multiple columns of light-emitting elements 20.

[0047] For example, the light-emitting element 20 includes at least two nanopillar light-emitting units 201 sequentially stacked along a direction perpendicular to the substrate 10. Each nanopillar light-emitting unit 201 includes a quantum well film layer 201b of the same material. The quantum well film layer 201b can be made of various materials, such as InGaN, GaN, etc., but is not limited to these. For example, the quantum well film layer 201b includes alternating InGaN film layers and GaN film layers.

[0048] For example, the nanopillar light-emitting unit 201 is formed as a columnar structure, and the diameter of the at least two nanopillar light-emitting units 201 decreases sequentially in the direction parallel to the substrate 10 along the direction away from the substrate 10. The diameter of the quantum well film layer 201b in the at least two nanopillar light-emitting units 201 decreases sequentially in the direction parallel to the substrate 10 along the direction away from the substrate 10, and the at least two nanopillar light-emitting units emit different colors.

[0049] More specifically, the principle of controlling the emission color by changing the diameter of the nanopillar emitting unit 201 is as follows: the higher the In content, the narrower the bandgap and the longer the wavelength; due to the beaming effect of adjacent nanopillars and the difference in diffusion length between Ga and In adsorbed atoms on the sidewalls, the amount of Ga atoms moving towards the top decreases as the nanopillar diameter increases, meaning that larger nanopillar emitting units 201 have longer emission wavelengths. Therefore, by changing the diameter of the nanopillar emitting unit 201, it is possible to achieve the emission of light of any wavelength in the blue to red band.

[0050] As can be seen from the specific structure of the above-mentioned display device, in the display device provided in the embodiments of this disclosure, the light-emitting element 20 includes at least two nanopillar light-emitting units 201 stacked together, each nanopillar light-emitting unit 201 includes a quantum well film layer 201b of the same material, and the diameter of the quantum well film layer 201b in the at least two nanopillar light-emitting units 201 decreases sequentially along the direction away from the substrate 10.

[0051] Since the emission wavelength of each nanopillar light-emitting unit 201 can be controlled by adjusting the diameter of each nanopillar light-emitting unit 201, in the display device provided in this embodiment, by setting the light-emitting element 20 to include at least two nanopillar light-emitting units 201 stacked together, the diameter of the quantum well film layer 201b in the at least two nanopillar light-emitting units 201 decreases sequentially in the direction away from the substrate 10, so that different nanopillar light-emitting units 201 belonging to the same light-emitting element 20 can emit light of different colors, that is, the emission colors of the at least two nanopillar light-emitting units are different. In this way, each light-emitting element 20 can be formed into a full-color nanopillar light-emitting element 20, thereby making the display device a full-color display device capable of full-color display.

[0052] In the display device provided in this embodiment, each of the nanopillar light-emitting units 201 is provided with a quantum well film layer 201b of the same material. This not only reduces the epitaxial difficulty when fabricating each of the nanopillar light-emitting units 201 using epitaxial growth technology, but also avoids the problem of large differences in current density between different MQW materials and avoids the problem of large differences in turn-on voltage between nanopillar light-emitting units 201 of different colors.

[0053] Please refer to Figures 1 to 13. In some embodiments, the nanopillar light-emitting unit 201 further includes an N-type semiconductor layer 201a and a P-type semiconductor layer 201c stacked together, and the quantum well film layer 201b is located between the N-type semiconductor layer 201a and the P-type semiconductor layer 201c.

[0054] The light-emitting element 20 further includes at least one tunneling film layer (e.g., a first tunneling film layer 31 and a second tunneling film layer 32). In the same light-emitting element 20, a tunneling film layer is provided between two adjacent nanopillar light-emitting units 201. The tunneling film layer is coupled to a P-type semiconductor layer 201c in one nanopillar light-emitting unit 201 and an N-type semiconductor layer 201a in another nanopillar light-emitting unit 201, respectively. The tunneling film layer is used to transport charge carriers to the semiconductor layer adjacent to the side of the tunneling film layer facing away from the substrate.

[0055] The light-emitting element 20 further includes at least one common electrode layer (e.g., a first common electrode layer 411 and a second common electrode layer 421), which is coupled to a semiconductor layer adjacent to the side of the corresponding tunnel junction layer facing the substrate 10.

[0056] For example, the nanopillar light-emitting unit 201 includes the N-type semiconductor layer 201a, the quantum well film layer 201b, and the P-type semiconductor layer 201c, which are sequentially stacked in a direction away from the substrate 10; or, the nanopillar light-emitting unit 201 includes the P-type semiconductor layer 201c, the quantum well film layer 201b, and the N-type semiconductor layer 201a, which are sequentially stacked in a direction away from the substrate 10.

[0057] For example, the N-type semiconductor layer 201a may be made of a variety of materials, such as GaN doped with Si, but is not limited to this. The P-type semiconductor layer 201c may be made of a variety of materials, such as GaN doped with Mg, but is not limited to this.

[0058] For example, in the same nanopillar light-emitting unit 201, the orthographic projections of the quantum well film layer 201b on the substrate 10, the orthographic projections of the P-type semiconductor layer 201c on the substrate 10, and the orthographic projections of the N-type semiconductor layer 201a on the substrate 10 all overlap.

[0059] For example, the tunnel membrane layer includes a p-GaN film layer, an i-AlGaN film layer, and an n-GaN film layer stacked sequentially.

[0060] For example, the thickness of the tunnel membrane layer is typically between a few nanometers and tens of nanometers, but is not limited to this.

[0061] For example, the tunneling conjunctival layer can simultaneously transport electrons and holes, or the tunneling conjunctival layer can transport electrons, or the tunneling conjunctival layer can transport holes.

[0062] For example, in each nanopillar light-emitting unit 201, the N-type semiconductor layer 201a, the quantum well film layer 201b, and the P-type semiconductor layer 201c are sequentially stacked in a direction away from the substrate 10, and the diameters of the N-type semiconductor layer 201a, the quantum well film layer 201b, and the P-type semiconductor layer 201c in the same nanopillar light-emitting unit 201 are approximately the same; the common electrode layer is coupled to the P-type semiconductor layer 201c adjacent to the side of the corresponding tunnel junction film layer facing the substrate 10. In this case, the P-type semiconductor layer 201c adjacent to the side of the tunnel junction layer facing the substrate 10 is in contact with the common electrode layer, and the holes required by the P-type semiconductor layer 201c can be directly injected through the common electrode layer; the electrons required by the N-type semiconductor layer 201a adjacent to the side of the tunnel junction layer facing away from the substrate 10 need to be injected through the tunnel junction layer, that is, the electrons injected by the common electrode layer are further injected through the tunnel junction layer into the N-type semiconductor layer 201a adjacent to the side of the tunnel junction layer facing away from the substrate 10.

[0063] Since the introduction of the tunneling membrane layer utilizes the quantum tunneling effect, allowing electrons and holes to pass through a thin barrier layer, a tunneling membrane layer is provided between two adjacent nanopillar light-emitting units 201 in the same light-emitting element 20. The common electrode layer is coupled to the semiconductor layer adjacent to the side of the corresponding tunneling membrane layer facing the substrate 10, so that electrons and holes can be injected through the common electrode layer into the P-type semiconductor layer 201c in one nanopillar light-emitting unit 201 and the N-type semiconductor layer 201a in the adjacent other nanopillar light-emitting unit 201.

[0064] In the display device provided by the above embodiments, by introducing the tunnel conjunctival layer and the common electrode layer, the number of electrodes that need to be fabricated in the display device is reduced, thereby simplifying the electrode fabrication process and reducing the difficulty of electrode fabrication.

[0065] As shown in Figure 10, in some embodiments, the plurality of light-emitting elements 20 are divided into multiple columns of light-emitting elements 20, and each column of light-emitting elements 20 includes a plurality of light-emitting elements 20 arranged along the column direction; in the same column of light-emitting elements 20, the common electrode layer corresponding to the same tunnel membrane layer included in each light-emitting element 20 is formed into a common electrode part of an integral structure (e.g., the first common electrode part 41 and the second common electrode part 42).

[0066] It should be noted that the same tunnel junction layer refers to all tunnel junction layers located on the same layer that are formed simultaneously in the same process. The common electrode layer corresponding to the tunnel junction layer meets the condition that the common electrode layer can be coupled to the semiconductor layer adjacent to the side of the corresponding tunnel junction layer facing the substrate 10, for injecting charge carriers into the corresponding tunnel junction layer.

[0067] Since the electrodes in the nanopillar light-emitting unit 201 are small in size, electrode fabrication is difficult. Therefore, the above-mentioned arrangement allows the common electrode part of the integrated structure to have a larger size, which helps to simplify the process and reduce the difficulty of electrode fabrication.

[0068] As shown in Figure 10, in some embodiments, in at least two adjacent rows of light-emitting elements 20, the same tunnel junction layer corresponds to the same common electrode portion; that is, the same common electrode portion can be coupled to the semiconductor layer adjacent to the same tunnel junction layer on the side facing the substrate 10 in the two adjacent rows of light-emitting elements 20, for injecting charge carriers into the tunnel junction layer corresponding to the two adjacent rows of light-emitting elements 20, and also for injecting charge carriers into the semiconductor layer directly coupled to the common electrode portion.

[0069] The above arrangement allows at least some of the two adjacent rows of light-emitting elements 20 to reuse a common electrode section, which helps to further simplify the process and reduce the difficulty of electrode fabrication.

[0070] As shown in Figure 10, in some embodiments, the common electrode portions corresponding to the same tunnel membrane layer are coupled to each other through electrode connection portions (e.g., first electrode connection portion 431 and second electrode connection portion 432).

[0071] For example, each of the common electrode portions corresponding to the same tunnel membrane layer and the electrode connection portion coupled thereto are formed into an integral structure.

[0072] The above arrangement allows the common electrode portions and the electrode connection portions to form a larger pattern, which helps to simplify the process and reduce the difficulty of electrode fabrication.

[0073] As shown in Figures 8 to 13, in some embodiments, the nanopillar light-emitting unit 201 further includes a first electrode 44 and a second electrode 45. The first electrode 44 is coupled to the N-type semiconductor layer 201a, and the second electrode 45 is coupled to the P-type semiconductor layer 201c. The common electrode layer is multiplexed as: the electrode of the nanopillar light-emitting unit 201 adjacent to the substrate 10 that is far from the substrate 10, and the electrode of the nanopillar light-emitting unit 201 adjacent to the substrate 10 that is far from the substrate 10.

[0074] For example, each of the nanopillar light-emitting units 201 includes a first electrode, an N-type semiconductor layer 201a, a quantum well film layer 201b, a P-type semiconductor layer 201c, and a second electrode. Taking an example where the nanopillar light-emitting unit 201 includes the N-type semiconductor layer 201a, the quantum well film layer 201b, and the P-type semiconductor layer 201c stacked sequentially along a direction away from the substrate 10, the common electrode layer is reused as: the second electrode in the nanopillar light-emitting unit 201 adjacent to it and close to the substrate 10, and the first electrode in the nanopillar light-emitting unit 201 adjacent to it and far from the substrate 10.

[0075] For example, the first electrode and the second electrode are transparent electrodes, for example, they can be made of indium tin oxide (ITO) material, but are not limited to this.

[0076] In the display device provided in the above embodiments, by introducing the common electrode layer, the number of electrodes that need to be fabricated in the display device is reduced, thereby simplifying the electrode fabrication process and reducing the difficulty of electrode fabrication.

[0077] As shown in Figures 9 and 10, in some embodiments, in each of the light-emitting elements 20, in the nanopillar light-emitting unit 201 closest to the substrate 10, the semiconductor layer located between the quantum well film layer 201b and the substrate 10 is formed as an integral semiconductor film layer, and the electrode coupled to the integral semiconductor film layer is located on the side of the integral semiconductor film layer facing away from the substrate 10.

[0078] In each of the light-emitting elements 20, in the nanopillar light-emitting unit 201 that is furthest from the substrate 10, the electrode coupled to the semiconductor layer furthest from the substrate 10 is formed as an integral electrode film layer.

[0079] The display device further includes a first conductive pad 51, a second conductive pad 52 and at least one third conductive pad 53 disposed on the same layer. The first conductive pad 51 is coupled to the electrode coupled to the entire semiconductor film layer, the second conductive pad 52 is coupled to the entire electrode film layer, and the third conductive pad 53 is coupled to the corresponding electrode connection portion.

[0080] For example, the substrate 10 includes a sapphire substrate, but is not limited to this.

[0081] Taking the nanopillar light-emitting unit 201, which includes the N-type semiconductor layer 201a, the quantum well film layer 201b, and the P-type semiconductor layer 201c sequentially stacked along a direction away from the substrate 10, as an example:

[0082] In each of the light-emitting elements 20, in the nanopillar light-emitting unit 201 closest to the substrate 10, the N-type semiconductor layer 201a is formed as an integral N-type semiconductor film layer, and the first electrode coupled to the integral N-type semiconductor film layer is located on the side of the integral N-type semiconductor film layer facing away from the substrate 10.

[0083] In each of the light-emitting elements 20, in the nanopillar light-emitting unit 201 furthest from the substrate 10, the second electrode coupled to the P-type semiconductor layer 201c is formed as an integral second electrode film layer.

[0084] For example, the first conductive pad 51, the second conductive pad 52, and at least one third conductive pad 53 are formed simultaneously in the same patterning process. The conductive pads can be made of a variety of materials, including, but not limited to, one or more of aluminum, silver, rhodium, zinc, gold, germanium, nickel, chromium, platinum, tin, copper, tungsten, indium tin oxide, palladium, indium, and titanium.

[0085] For example, the first conductive pad 51 is coupled to the electrode of the entire semiconductor film layer through a via penetrating the insulating layer 70, and the second conductive pad 52 is coupled to the electrode film layer of the entire surface through a via penetrating the insulating layer 70. For example, the material of the insulating layer 70 includes SiO2, SiN, etc., but is not limited to these.

[0086] In practical applications, the first conductive pad 51, the second conductive pad 52, and the third conductive pad 53 of the display device are bonded to the driving backplate.

[0087] As shown in Figures 11 and 12, in some embodiments, in each of the light-emitting elements 20, in the nanopillar light-emitting unit 201 closest to the substrate 10, the semiconductor layer located between the quantum well film layer 201b and the substrate 10 is formed as an integral semiconductor film layer, and the electrode coupled to the integral semiconductor film layer is located between the integral semiconductor film layer and the substrate 10.

[0088] In each of the light-emitting elements 20, in the nanopillar light-emitting unit 201 that is furthest from the substrate 10, the electrode coupled to the semiconductor layer furthest from the substrate 10 is formed as an integral electrode film layer.

[0089] The substrate 10 includes an integrated circuit substrate 10, which includes a first pin 61, a second pin 62, and at least one third pin; the first pin 61 is coupled to an electrode coupled to the entire semiconductor film layer.

[0090] The display device further includes a fourth conductive pad 54 and at least one fifth conductive pad. The fourth conductive pad 54 is coupled to the entire electrode film layer and the second pin 62, respectively. The fifth conductive pad is coupled to the corresponding electrode connection portion and the corresponding third pin, respectively.

[0091] For example, the substrate 10 includes an integrated circuit substrate, which includes a silicon-based substrate or a glass-based substrate, but is not limited thereto.

[0092] Taking the nanopillar light-emitting unit 201, which includes the N-type semiconductor layer 201a, the quantum well film layer 201b, and the P-type semiconductor layer 201c sequentially stacked along a direction away from the substrate 10, as an example:

[0093] In each of the light-emitting elements 20, in the nanopillar light-emitting unit 201 closest to the substrate 10, the N-type semiconductor layer 201a is formed as an integral N-type semiconductor film layer, and the first electrode coupled to the integral N-type semiconductor film layer is located between the integral N-type semiconductor film layer and the substrate 10.

[0094] In each of the light-emitting elements 20, in the nanopillar light-emitting unit 201 furthest from the substrate 10, the second electrode coupled to the P-type semiconductor layer 201c is formed as an integral second electrode film layer.

[0095] For example, the fourth conductive pad 54 and the fifth conductive pad are formed simultaneously in the same patterning process. The conductive pads can be made of a variety of materials, including, but not limited to, one or more of the following: aluminum, silver, rhodium, zinc, gold, germanium, nickel, chromium, platinum, tin, copper, tungsten, indium tin oxide, palladium, indium, and titanium.

[0096] For example, the first pin 61 is directly coupled to the electrode coupled to the entire semiconductor film layer. The fourth conductive pad 54 is directly coupled to the entire electrode film layer and coupled to the second pin 62 through a via penetrating the insulating layer 70; the fourth conductive pad 54 may also extend along the side surface of the entire display device to the substrate 10 to achieve coupling with the second pin 62 on the substrate 10. The fifth conductive pad is coupled to the corresponding electrode connection portion and the corresponding third pin respectively through a via penetrating the insulating layer 70.

[0097] In practical applications, the display device with the above structure requires two transfers. The first transfer is to transfer the transition display device to a temporary substrate before fabricating the conductive pad of the display device. At this time, the light-emitting side of the transition display device is close to the temporary substrate. The second transfer is to transfer the transition display device from the temporary substrate to the final integrated circuit substrate 10. After the second transfer, the temporary substrate is removed, and the fourth conductive pad 54 and the fifth conductive pad are formed.

[0098] As shown in Figures 1 to 13, in some embodiments, the light-emitting element 20 includes a first nanopillar light-emitting unit 201, a second nanopillar light-emitting unit 201, and a third nanopillar light-emitting unit 201 stacked sequentially along a direction away from the substrate 10, wherein the N-type semiconductor layer 201a, the quantum well film layer 201b, and the P-type semiconductor layer 201c are arranged sequentially in each nanopillar light-emitting unit 201;

[0099] The light-emitting element 20 includes a first tunneling film layer 31 and a second tunneling film layer 32. The first tunneling film layer 31 is located between the P-type semiconductor layer 201c of the first nanopillar light-emitting unit 201 and the N-type semiconductor layer 201a of the second nanopillar light-emitting unit 201. The second tunneling film layer 32 is located between the P-type semiconductor layer 201c of the second nanopillar light-emitting unit 201 and the N-type semiconductor layer 201a of the third nanopillar light-emitting unit 201.

[0100] The light-emitting element 20 includes a first common electrode layer 411 and a second common electrode layer 421. The first common electrode layer 411 is coupled to a P-type semiconductor layer 201c adjacent to the side of the corresponding first tunnel junction layer 31 facing the substrate 10. The second common electrode layer 421 is coupled to a P-type semiconductor layer 201c adjacent to the side of the corresponding second tunnel junction layer 32 facing the substrate 10.

[0101] For example, the first nanopillar light-emitting unit 201 includes a red nanopillar light-emitting unit R, the second nanopillar light-emitting unit 201 includes a green nanopillar light-emitting unit G, and the third nanopillar light-emitting unit 201 includes a blue nanopillar light-emitting unit B. R- represents the first electrode of the red nanopillar light-emitting unit R, and R+ represents the second electrode of the red nanopillar light-emitting unit R; G- represents the first electrode of the green nanopillar light-emitting unit G, and G+ represents the second electrode of the green nanopillar light-emitting unit G; B- represents the first electrode of the blue nanopillar light-emitting unit B, and B+ represents the second electrode of the blue nanopillar light-emitting unit B.

[0102] For example, the diameter of the red nanopillar luminescent unit R is between 800 nm and 2000 nm; the diameter of the green nanopillar luminescent unit G is between 80 nm and 120 nm; and the diameter of the blue nanopillar luminescent unit B is between 50 nm and 90 nm.

[0103] For example, the first common electrode layer 411 is reused as a first electrode (e.g., G-) of the green nanopillar light-emitting unit G and a second electrode (e.g., R+) of the red nanopillar light-emitting unit 201. The second common electrode layer 421 is reused as a second electrode (e.g., G+) of the green nanopillar light-emitting unit 201 and a first electrode (e.g., B-) of the blue nanopillar light-emitting unit 201.

[0104] Without the introduction of a tunneling conjunctival layer and a common electrode layer, the light-emitting element 20 would require six electrodes, meaning each nanopillar light-emitting unit 201 would correspond to two electrodes. In the display device provided by the above embodiment, by setting the tunneling conjunctival layer, the quantum tunneling effect is utilized, allowing electrons and holes to pass through a thin barrier layer, thereby achieving injection of both onto a common electrode layer. This means that the first electrode of the green nanopillar light-emitting unit G and the second electrode of the red nanopillar light-emitting unit R can share a first common electrode layer 411, and the second electrode of the green nanopillar light-emitting unit G and the first electrode of the blue nanopillar light-emitting unit B can share a second common electrode layer 421. Thus, the light-emitting element 20 only requires four electrodes, effectively reducing the number of electrodes.

[0105] For example, in the same column of light-emitting elements 20, a first common electrode layer 411 corresponding to each first tunnel conjunctival layer 31 is formed into an integral structure as a first common electrode portion 41; and / or, a second common electrode layer 421 corresponding to each second tunnel conjunctival layer 32 is formed into an integral structure as a second common electrode portion 42.

[0106] For example, in at least two partially adjacent rows of light-emitting elements 20, each first tunnel conjunctival layer 31 corresponds to the same first common electrode portion 41; and / or, each second tunnel conjunctival layer 32 corresponds to the same second common electrode portion 42.

[0107] For example, each of the first common electrode portions 41 is coupled to each other via a first electrode connection portion 431; and / or, each of the second common electrode portions 42 is coupled to each other via a second electrode connection portion 432. The first common electrode portions 41 and the second common electrode portions 42 are alternately arranged along a first direction, and the first electrode connection portion 431 and the second electrode connection portion 432 are opposite each other along a second direction, the second direction intersecting the first direction.

[0108] The above configuration not only further simplifies the electrode structure of the display device, but also forms a large-area common electrode layer, which helps to further reduce the difficulty of manufacturing electrodes.

[0109] As shown in Figures 8, 9, 12, and 13, in some embodiments, the N-type semiconductor layer 201a of the nanopillar light-emitting unit 201 closest to the substrate 10 in each light-emitting element 20 is formed as an integral film layer; and / or, the quantum well film layer 201b of the nanopillar light-emitting unit 201 closest to the substrate 10 in each light-emitting element 20 is formed as an integral film layer; and / or, the P-type semiconductor layer 201c of the nanopillar light-emitting unit 201 closest to the substrate 10 in each light-emitting element 20 is formed as an integral film layer.

[0110] The above configuration does not restrict the diameter of the nanopillar light-emitting unit 201 closest to the substrate 10, which can further simplify the manufacturing process of the display device and reduce the manufacturing difficulty of the display device while ensuring the normal operation of the display device.

[0111] This disclosure also provides a display device, including a plurality of display devices provided in the above embodiments.

[0112] It should be noted that the display device can be any product or component with display function, such as a television, monitor, digital photo frame, mobile phone, or tablet computer. The display device also includes flexible circuit boards, printed circuit boards, and backplanes.

[0113] When the display device provided in the above embodiments includes a first conductive pad 51, a second conductive pad 52, and a third conductive pad 53, that is, when the display device uses a sapphire substrate, the first conductive pads 51, the second conductive pads 52, and the third conductive pads 53 of multiple display devices can be bonded to a driving backplane to form the display device.

[0114] When the display device provided in the above embodiments includes the fourth conductive pad 54 and the fifth conductive pad, that is, when the display device adopts an integrated circuit substrate, multiple transitional display devices can be transferred to the final integrated circuit substrate in two transfers, and then the fourth conductive pad 54 and the fifth conductive pad are formed on each transitional display device to form the display device, and finally the display device is formed.

[0115] In the display device provided in the above embodiments, by setting the light-emitting element 20 to include at least two stacked nanopillar light-emitting units 201, and the diameter of the quantum well film layer 201b in the at least two nanopillar light-emitting units 201 decreasing sequentially in the direction away from the substrate 10, different nanopillar light-emitting units 201 belonging to the same light-emitting element 20 can emit light of different colors, that is, the light-emitting colors of the at least two nanopillar light-emitting units are different. In this way, each light-emitting element 20 can be formed into a full-color nanopillar light-emitting element 20, thereby making the display device a full-color display device capable of full-color display. In the display device provided in the above embodiments, setting each nanopillar light-emitting unit 201 to include a quantum well film layer 201b of the same material not only reduces the epitaxial difficulty when fabricating each nanopillar light-emitting unit 201 using epitaxial growth technology, but also avoids the problem of large differences in current density between different MQW materials, and avoids the problem of large differences in turn-on voltage between nanopillar light-emitting units 201 of different colors.

[0116] The display device provided in this disclosure, when including the above-described display device, also has the above-described beneficial effects, which will not be repeated here.

[0117] This disclosure also provides a method for manufacturing a display device, used to manufacture the display device provided in the above embodiments; the manufacturing method includes the step of manufacturing a plurality of light-emitting elements 20 on a substrate 10; the step of manufacturing the light-emitting elements 20 specifically includes:

[0118] The light-emitting element 20 may be fabricated using epitaxial growth technology, comprising at least two stacked nanopillar light-emitting units 201; or, the light-emitting element 20 may be fabricated using nanoimprint lithography technology, comprising at least two stacked nanopillar light-emitting units 201.

[0119] As shown in Figures 1 to 10, taking the nanopillar light-emitting unit 201, which includes an N-type semiconductor layer 201a, a quantum well film layer 201b, and a P-type semiconductor layer 201c sequentially stacked along a direction away from the substrate 10, as an example, when the light-emitting element 20 includes at least two stacked nanopillar light-emitting units 201 using epitaxial growth technology, the fabrication process of the display device is as follows:

[0120] Step 1: As shown in Figure 1, the N-type semiconductor layer 201a, quantum well film layer 201b, and P-type semiconductor layer 201c, as well as the tunnel junction film layer located between adjacent nanopillar light-emitting units 201, are fabricated in the selective region using epitaxial growth technology.

[0121] Step 2: As shown in Figure 2, an insulating layer 70 is deposited to form an insulating layer. The insulating layer 70 at least completely covers the side surface of each light-emitting element 20. The insulating layer 70 may also further completely cover each light-emitting element 20, that is, the orthogonal projection of each light-emitting element 20 on the substrate 10 is located inside the insulating layer 70. The insulating layer 70 covers the top surface of the nanopillar light-emitting unit 201 furthest from the substrate 10, facing away from the substrate 10.

[0122] Step 3: As shown in Figure 3, the insulating layer 70 is etched to expose the location where the electrode needs to be deposited. This electrode includes the entire common electrode layer and the first electrode in the nanopillar light-emitting unit 201 closest to the substrate 10. It is worth noting that when etching to expose the common electrode layer and the first electrode in the nanopillar light-emitting unit 201 closest to the substrate 10, it is necessary to ensure that the remaining insulating layer 70 can cover the sides of each nanopillar light-emitting unit 201.

[0123] Step 4: As shown in Figure 4, fabricate all common electrode layers, as well as the first electrode in the nanopillar light-emitting unit 201 closest to the substrate 10.

[0124] Step 5: As shown in Figure 5, an insulating layer 70 is deposited again, which fills the step difference formed in Step 3. It should be noted that since the same material is used for the insulating layer 70 formed each time, the boundary between the two insulating layers 70 is not shown in the attached figure.

[0125] It is worth noting that if the insulating layer 70 fabricated in step two covers the top surface of the nanopillar light-emitting unit 201 furthest from the substrate 10 facing away from the substrate 10, an additional etching process is required after step five to remove the insulating layer 70 from the top surface of the nanopillar light-emitting unit 201 furthest from the substrate 10 facing away from the substrate 10, thereby exposing the top surface of the P-type semiconductor layer 201c in the nanopillar light-emitting unit 201 furthest from the substrate 10. If the insulating layer 70 fabricated in step two does not cover the top surface of the nanopillar light-emitting unit 201 furthest from the substrate 10 facing away from the substrate 10, this etching process is not required.

[0126] Step 6: As shown in Figure 6, fabricate the second electrode in the nanopillar light-emitting unit 201 furthest from the substrate 10, and make contact with the top surface of the P-type semiconductor layer 201c in the nanopillar light-emitting unit 201 furthest from the substrate 10.

[0127] Step 7: As shown in Figure 7, fabricate the first conductive pad 51, the second conductive pad 52, and at least two third conductive pads 53.

[0128] Step 8: As shown in Figure 8, perform deep etching to expose the substrate 10 at the edge of the display device, forming an independent display device.

[0129] In the fabrication method provided in the above embodiments, when at least two stacked nanopillar light-emitting units 201 of the light-emitting element 20 are fabricated using epitaxial growth technology, the dislocation density of each nanopillar light-emitting unit 201 belonging to the same light-emitting element 20 is small, and the sidewall damage caused by top-down etching can be avoided.

[0130] When fabricating the light-emitting element 20 comprising at least two stacked nanopillar light-emitting units 201 using nanoimprint technology, a complete film layer can be deposited first, and then the entire film layer can be patterned using nanoimprint technology to finally form the nanopillar light-emitting unit 201.

[0131] In the manufacturing method provided in the above embodiments, when the light-emitting element 20 includes at least two stacked nanopillar light-emitting units 201 using nanoimprint technology, the epitaxial difficulty of the film layer can be reduced, thereby reducing the manufacturing difficulty of the display device.

[0132] It should be noted that, in the embodiments of this disclosure, "same layer" can refer to film layers located on the same structural layer. Alternatively, for example, film layers located on the same layer can be layer structures formed by using the same film deposition process to form a specific pattern, and then patterning the film layer using the same photomask through a single patterning process. Depending on the specific pattern, the single patterning process may include multiple exposure, development, or etching processes, and the specific pattern in the formed layer structure can be continuous or discontinuous. These specific patterns may also be at different heights or have different thicknesses.

[0133] In the various method embodiments of this disclosure, the sequence numbers of each step are not intended to limit the order of the steps. For those skilled in the art, any changes in the order of the steps are within the scope of protection of this disclosure without any creative effort.

[0134] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the method embodiments are basically similar to the product embodiments, so the description is relatively simple, and the relevant parts can be referred to the description of the product embodiments.

[0135] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as “connection,” “coupled,” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0136] It is understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "below" another element, the element may be located "directly" on or "below" the other element, or there may be intermediate elements. In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples. The above descriptions are merely specific embodiments of this disclosure, but the scope of protection of this disclosure 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 disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A display device, comprising: The substrate and a plurality of light-emitting elements disposed on the substrate, wherein the light-emitting elements include at least two nanopillar light-emitting units stacked together, each nanopillar light-emitting unit including a quantum well film layer of the same material, the diameter of the quantum well film layer in the at least two nanopillar light-emitting units decreasing sequentially in the direction away from the substrate, and the at least two nanopillar light-emitting units emitting different colors.

2. The display device according to claim 1, wherein, The nanopillar light-emitting unit further includes an N-type semiconductor layer and a P-type semiconductor layer stacked together, and the quantum well film layer is located between the N-type semiconductor layer and the P-type semiconductor layer; The light-emitting element further includes at least one tunnel junction layer. In the same light-emitting element, there is a tunnel junction layer between two adjacent nanopillar light-emitting units. The tunnel junction layer is coupled to a P-type semiconductor layer in one nanopillar light-emitting unit and an N-type semiconductor layer in another nanopillar light-emitting unit, respectively. The tunnel junction layer is used to transport charge carriers to the semiconductor layer adjacent to the side of the tunnel junction layer facing away from the substrate. The light-emitting element further includes at least one common electrode layer, which is coupled to a semiconductor layer adjacent to the side of the corresponding tunnel junction layer facing the substrate.

3. The display device according to claim 2, wherein, In each nanopillar light-emitting unit, the N-type semiconductor layer, the quantum well film layer, and the P-type semiconductor layer are stacked sequentially in a direction away from the substrate, and the diameters of the N-type semiconductor layer, the quantum well film layer, and the P-type semiconductor layer in the same nanopillar light-emitting unit are approximately the same; The common electrode layer is coupled to the P-type semiconductor layer adjacent to the side of the corresponding tunnel junction layer facing the substrate.

4. The display device according to claim 2, wherein, The plurality of light-emitting elements are divided into multiple columns of light-emitting elements, and each column of light-emitting elements includes a plurality of light-emitting elements arranged along the column direction; In the same row of light-emitting elements, the common electrode layer corresponding to the same tunnel membrane layer of each light-emitting element is formed into a common electrode part of an integral structure.

5. The display device according to claim 4, wherein, In at least two adjacent rows of light-emitting elements, the same tunneling membrane layer corresponds to the same common electrode portion.

6. The display device according to claim 4, wherein, The common electrode portions corresponding to the same tunnel membrane layer are coupled to each other through electrode connection portions.

7. The display device according to claim 6, wherein, The nanopillar light-emitting unit further includes a first electrode and a second electrode, wherein the first electrode is coupled to the N-type semiconductor layer and the second electrode is coupled to the P-type semiconductor layer; The common electrode layer is reused as: the electrode of the adjacent nanopillar light-emitting unit that is far from the substrate and the electrode of the adjacent nanopillar light-emitting unit that is far from the substrate that is close to the substrate.

8. The display device according to claim 7, wherein, In each of the light-emitting elements, in the nanopillar light-emitting unit closest to the substrate, the semiconductor layer located between the quantum well film and the substrate is formed as a whole semiconductor film, and the electrode coupled to the whole semiconductor film is located on the side of the whole semiconductor film facing away from the substrate. In each of the light-emitting elements, in the nanopillar light-emitting unit furthest from the substrate, the electrode coupled to the semiconductor layer furthest from the substrate is formed as an integral whole electrode film layer. The display device further includes a first conductive pad, a second conductive pad, and at least one third conductive pad disposed on the same layer. The first conductive pad is coupled to an electrode coupled to the entire semiconductor film layer, the second conductive pad is coupled to the entire electrode film layer, and the third conductive pad is coupled to a corresponding electrode connection portion.

9. The display device according to claim 7, wherein, In each of the light-emitting elements, in the nanopillar light-emitting unit closest to the substrate, the semiconductor layer located between the quantum well film layer and the substrate is formed as an integral semiconductor film layer, and the electrode coupled to the integral semiconductor film layer is located between the integral semiconductor film layer and the substrate. In each of the light-emitting elements, in the nanopillar light-emitting unit furthest from the substrate, the electrode coupled to the semiconductor layer furthest from the substrate is formed as an integral whole electrode film layer. The substrate includes an integrated circuit substrate, which includes a first pin, a second pin, and at least one third pin; the first pin is coupled to an electrode coupled to the entire semiconductor film layer. The display device further includes a fourth conductive pad and at least one fifth conductive pad. The fourth conductive pad is coupled to the entire electrode film layer and the second pin, respectively, and the fifth conductive pad is coupled to the corresponding electrode connection portion and the corresponding third pin, respectively.

10. The display device according to any one of claims 6 to 9, wherein, The light-emitting element includes a first nanopillar light-emitting unit, a second nanopillar light-emitting unit, and a third nanopillar light-emitting unit stacked sequentially along a direction away from the substrate, wherein the N-type semiconductor layer, the quantum well film layer, and the P-type semiconductor layer are arranged sequentially in each nanopillar light-emitting unit; The light-emitting element includes a first tunneling film layer and a second tunneling film layer. The first tunneling film layer is located between the P-type semiconductor layer of the first nanopillar light-emitting unit and the N-type semiconductor layer of the second nanopillar light-emitting unit. The second tunneling film layer is located between the P-type semiconductor layer of the second nanopillar light-emitting unit and the N-type semiconductor layer of the third nanopillar light-emitting unit. The light-emitting element includes a first common electrode layer and a second common electrode layer. The first common electrode layer is coupled to a P-type semiconductor layer adjacent to the side of the corresponding first tunnel junction layer facing the substrate. The second common electrode layer is coupled to a P-type semiconductor layer adjacent to the side of the corresponding second tunnel junction layer facing the substrate.

11. The display device according to claim 10, wherein, In the same row of light-emitting elements, the first common electrode layer corresponding to each first tunnel conjunctival layer is formed as a first common electrode portion of an integral structure; and / or, the second common electrode layer corresponding to each second tunnel conjunctival layer is formed as a second common electrode portion of an integral structure.

12. The display device according to claim 11, wherein, In at least two adjacent rows of light-emitting elements, each first tunnel conjunctival layer corresponds to the same first common electrode portion; and / or, each second tunnel conjunctival layer corresponds to the same second common electrode portion.

13. The display device according to claim 11, wherein, Each of the first common electrode portions is coupled to each other through a first electrode connection portion; and / or, each of the second common electrode portions is coupled to each other through a second electrode connection portion; The first common electrode portion and the second common electrode portion are alternately arranged along a first direction, and the first electrode connection portion and the second electrode connection portion are opposite each other along a second direction, the second direction intersecting the first direction.

14. The display device according to any one of claims 2 to 9, wherein, The N-type semiconductor layer of the nanopillar light-emitting unit closest to the substrate in each light-emitting element is formed as an integral film layer; and / or, the quantum well film layer of the nanopillar light-emitting unit closest to the substrate in each light-emitting element is formed as an integral film layer; and / or, the P-type semiconductor layer of the nanopillar light-emitting unit closest to the substrate in each light-emitting element is formed as an integral film layer.

15. A display device comprising a plurality of display devices as claimed in any one of claims 1 to 14.

16. A method for manufacturing a display device, used to manufacture a display device as described in any one of claims 1 to 14; the method includes the step of manufacturing a plurality of light-emitting elements on a substrate; the step of manufacturing the light-emitting elements specifically includes: The light-emitting element comprises at least two stacked nanopillar light-emitting units fabricated using epitaxial growth technology; or, The light-emitting element is fabricated using nanoimprint lithography, comprising at least two stacked nanopillar light-emitting units.

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