Light emitting diode and display device including the same

Abstract

Disclosed are a light emitting diode and a display device including the same. A light emitting diode includes: a base layer; a first semiconductor layer surrounding a side surface of the base layer; a first electrode on a first surface of the first semiconductor layer, the first electrode being electrically connected to the first semiconductor layer; and a second electrode on a second surface of the first semiconductor layer opposite to the first surface, the second electrode being electrically connected to the first semiconductor layer, in which the first electrode and the second electrode overlap each other.

Description

Technical Field

[0001] The present disclosure relates to a light-emitting diode and a display device including the light-emitting diode. Background Art

[0002] In addition to the display screen of a television or a monitor, the display device is also widely used as a display screen of a notebook computer, a tablet computer, a smart phone, a portable display device, and a portable information device. A liquid crystal display device and an organic light-emitting display device use a thin-film transistor as a switching element to display an image. Since the liquid crystal display device is not a self-luminous device, light irradiated from a backlight unit provided below the liquid crystal display panel is used to display an image. Since such a liquid crystal display device has a backlight unit, the design is limited, and the brightness and the response speed may deteriorate. Since the organic light-emitting display device includes an organic material, which is vulnerable to moisture, the reliability and the lifespan may deteriorate.

[0003] In recent years, research and development of a light-emitting diode display device using a micro light-emitting diode have become a focus as a next-generation display due to its high quality and high reliability.

[0004] In order to implement a high-definition light-emitting diode display device, it is necessary to apply a micro LED (uLED) having a small size. Also, in order to implement a high-quality light-emitting diode display device, a process of transferring the light-emitting diode to a substrate is required. In this case, since the micro LED has a very small size, it cannot be precisely transferred onto the substrate. For example, when the lower surface of the light-emitting diode needs to be transferred to contact the substrate, the light-emitting diode may flip during the transfer process, and the upper surface of the light-emitting diode may contact the substrate. Therefore, the electrodes of the light-emitting diode may not be normally connected to the driving element or the power line. Therefore, a problem of lighting defects may occur. Summary of the Invention

[0005] In view of the above problems, the present disclosure has been made, and an object of the present disclosure is to provide a light-emitting diode having a symmetric structure and a method of manufacturing the same.

[0006] According to one aspect of the present disclosure, the above and other objects can be achieved by providing a light-emitting diode including: a base layer; a first semiconductor layer surrounding a side surface of the base layer; a first electrode provided on a first surface of the first semiconductor layer, the first electrode being electrically connected to the first semiconductor layer; and a second electrode on a second surface of the first semiconductor layer opposite to the first surface; the second electrode being electrically connected to the first semiconductor layer, wherein the first electrode and the second electrode overlap each other.

[0007] According to one aspect of the present disclosure, the above and other objects can be achieved by providing a display device including: a common voltage line; a thin film transistor on a substrate; and a light emitting diode on the substrate, the light emitting diode including a first semiconductor layer, a second semiconductor layer surrounding a side surface of the first semiconductor layer, a first electrode electrically connected to the first semiconductor layer, a second electrode electrically connected to the first semiconductor layer, a third electrode electrically connected to the second semiconductor layer, and a fourth electrode electrically connected to the second semiconductor layer, wherein one of the first electrode and the second electrode is electrically connected to the thin film transistor through a first connection electrode, and one of the third electrode and the fourth electrode is electrically connected to the common voltage line through a second connection electrode.

[0008] According to one aspect of the present disclosure, the above and other objects can be achieved by providing a light emitting diode including: a base layer including a first surface and a second surface opposite to the first surface of the base layer; a first semiconductor layer including a first surface and a second surface opposite to the first surface of the first semiconductor layer, the first semiconductor layer contacting and surrounding a side surface of the base layer, and the first surface of the first semiconductor layer being in the same plane as the first surface of the base layer; an active layer including a first surface and a second surface opposite to the first surface of the active layer, the active layer contacting and surrounding a side surface of the first semiconductor layer, and the first surface of the active layer being in the same plane as the first surface of the first semiconductor layer; a second semiconductor layer including a first surface and a second surface opposite to the first surface of the second semiconductor layer, the second semiconductor layer contacting and surrounding a side surface of the active layer; the first surface of the second semiconductor layer being in the same plane as the first surface of the active layer; a first pair of overlapping electrodes on the first surface and the second surface of the first semiconductor layer and the first surface and the second surface of the base layer, the first pair of overlapping electrodes being electrically connected to the first semiconductor layer; and a second pair of overlapping electrodes on the first surface and the second surface of the second semiconductor layer, the second pair of overlapping electrodes being electrically connected to the second semiconductor layer. Description of the Drawings

[0009] Figures 1 to 13 is a diagram showing a manufacturing process of a light emitting diode according to an embodiment of the present disclosure.

[0010] Figure 14 is a cross-sectional view of a light emitting diode according to an embodiment of the present disclosure.

[0011] Figure 15 is a cross-sectional view of a light emitting diode according to another embodiment of the present disclosure.

[0012] Figure 16 is a cross-sectional view of a display device according to an embodiment of the present disclosure. Detailed Description

[0013] Advantages and features of the present disclosure and its implementation method will be clarified by the embodiments described with reference to the accompanying drawings below. However, the present disclosure may be implemented in different forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0014] The shapes, sizes, ratios, angles, and quantities disclosed in the drawings used to describe the embodiments of the present disclosure are merely examples. Therefore, the present disclosure is not limited to the details shown. Throughout the specification, the same reference numerals denote the same elements. In the following description, when the detailed description of related known functions or configurations unnecessarily obscures the gist of the present disclosure, the detailed description will be omitted. In the case of using "comprising", "having", and "including" described in the present disclosure, another part may be added unless "only" is used. A term in the singular form may include the plural form unless otherwise mentioned.

[0015] When explaining an element, the element is interpreted as including an error band although not explicitly described.

[0016] When describing positional relationships, for example, when the positional relationship is described as "on...", "above...", "under...", and "next to...", one or more parts may be provided between two other parts unless "only" or "directly" is used.

[0017] It should be understood that although terms such as "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of the present disclosure, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element.

[0018] The features of the various embodiments of the present disclosure may be partially or wholly coupled or combined with each other, and may interoperate with each other differently and be technically driven, as can be fully understood by those skilled in the art. The embodiments of the present disclosure may be executed independently of each other, or may be executed together in a mutually dependent relationship.

[0019] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0020] Figures 1 to 13 is a view showing a manufacturing process of a light-emitting diode according to an embodiment of the present disclosure. Figures 1 to 13It can be achieved by process methods such as metalorganic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), plasma-enhanced chemical vapor deposition (PECVD), and vapor phase epitaxy (VPE).

[0021] Reference Figure 1 , a base layer 110 can be formed on the first substrate SUB1. The base layer 110 can be formed of a semiconductor material such as GaN, AlGaN, InGaN, or AlInGaN, and can be in an undoped state.

[0022] A mask MASK can be formed on the base layer 110. The mask MASK can include a plurality of holes H. That is, the mask MASK can expose a part of the upper surface of the base layer 110 through the plurality of holes H. Each of the plurality of holes H is spaced apart from each other and can have a circular shape.

[0023] Referring Figure 2 , the base layer 110 can grow in a direction perpendicular to the top surface of the first substrate SUB1. The base layer 110 can grow along the shape of the plurality of holes H of the mask MASK. Therefore, the base layer 110 can have protrusions 110a and flat portions 110b. Referring Figure 2 , since the plurality of holes H have a circular shape, the protrusions 110a can have a cylindrical shape. Figure 2 It is shown that the protrusions 110a have a cylindrical shape, and the description is not limited thereto. For example, the protrusions 110a can be elliptical cylinders having an elliptical cross-section or polyhedrons having a polygonal cross-section.

[0024] Referring Figure 3 , an n-type semiconductor layer 120 can be formed on the protrusions 110a of the base layer 110. The n-type semiconductor layer 120 can be formed by growing the base layer 110 and then doping with n-type impurities. That is, the n-type semiconductor layer 120 can be formed of a semiconductor material based on n-GaN, such as GaN, AlGaN, InGaN, or AlInGaN. In addition, Si, Ge, Se, Te, C, etc. can be used as impurities for doping the n-type semiconductor layer 120, but it is not limited thereto.

[0025] The n-type semiconductor layer 120 can cover the top surface and the side surfaces of the protrusions 110a of the base layer 110. In addition, the n-type semiconductor layer 120 can be formed to correspond to the shape of the protrusions 110a of the base layer 110. That is, since the protrusions 110a of the base layer 110 have a cylindrical shape, the n-type semiconductor layer 120 can also be formed in a cylindrical shape.

[0026] The amount of the n-type semiconductor layer 120 grown in the horizontal direction can be greater than the amount of the n-type semiconductor layer 120 grown in the vertical direction with respect to the upper surface of the first substrate SUB1. That is, the distance from the upper surface of the protrusion 110a of the base layer 110 to the upper surface of the n-type semiconductor layer 120 can be less than the distance from the side surface of the protrusion 110a of the base layer 110 to the side surface of the n-type semiconductor layer 120.

[0027] Reference Figure 4 , an active layer 130 can be formed on the n-type semiconductor layer 120. The active layer 130 can completely cover the top surface and the side surface of the n-type semiconductor layer 120. In addition, the active layer 130 can be formed to correspond to the shape of the n-type semiconductor layer 120. That is, since the n-type semiconductor layer 120 has a cylindrical shape, the active layer 130 can also be formed in a cylindrical shape.

[0028] The amount of the active layer 130 grown in the vertical direction and the amount of the active layer 130 grown in the horizontal direction can be the same or substantially the same with respect to the upper surface of the first substrate SUB1. That is, the active layer 130 can have a uniform thickness.

[0029] The active layer 130 can be a light-emitting layer that emits light. The active layer 130 can have a multi-quantum well (MQW) structure having a well layer and a barrier layer with a bandgap higher than that of the well layer. For example, the active layer 130 can have a multi-quantum well structure such as InGaN / GaN, but is not limited thereto.

[0030] Refer to Figure 5 , a p-type semiconductor layer 140 can be formed on the active layer 130. The p-type semiconductor layer 140 can be formed of a semiconductor material based on p-GaN, such as GaN, AlGaN, InGaN, or AlInGaN. In addition, impurities such as Mg, Zn, Be, etc. can be used to dope the p-type semiconductor layer 140, but are not limited thereto.

[0031] The p-type semiconductor layer 140 can cover the top surface and the side surface of the active layer 130. In addition, the p-type semiconductor layer 140 can be formed to correspond to the shape of the active layer 130. That is, since the active layer 130 has a cylindrical shape, the p-type semiconductor layer 140 can also be formed in a cylindrical shape.

[0032] The amount of the p-type semiconductor layer 140 grown in the horizontal direction can be greater than the amount of the p-type semiconductor layer 140 grown in the vertical direction with respect to the upper surface of the first substrate SUB1. That is, the distance from the upper surface of the active layer 130 to the upper surface of the p-type semiconductor layer 140 can be less than the distance from the side surface of the active layer 130 to the side surface of the p-type semiconductor layer 140.

[0033] Refer toFigure 6 , an etching process can be performed in a vertical direction on the top surface of the first substrate SUB1. Some regions of the n-type semiconductor layer 120, the active layer 130, and the p-type semiconductor layer 140 can be etched through the etching process. Accordingly, the top surfaces of the n-type semiconductor layer 120, the active layer 130, and the protrusion 110a of the base layer 110 can be exposed. Moreover, the top surfaces of the protrusion 110a of the base layer 110, the n-type semiconductor layer 120, the active layer 130, and the p-type semiconductor layer 140 can be located on the same plane. Additionally, the bottom surfaces of the base layer 110, the n-type semiconductor layer 120, the active layer 130, and the p-type semiconductor layer 140 can be located on the same plane.

[0034] The n-type semiconductor layer 120 can surround the side surface of the protrusion 110a of the base layer 110 without covering the top surface of the protrusion 110a of the base layer 110. In addition, the active layer 130 can surround the side surface of the n-type semiconductor layer 120 without covering the top surface of the n-type semiconductor layer 120. In addition, the p-type semiconductor layer 140 can surround the side surface of the active layer 130 without covering the top surface of the active layer 130.

[0035] Referring to Figure 7 , a part of the upper surface of the p-type semiconductor layer 140 can be etched. Accordingly, the p-type semiconductor layer 140 can include a first region 141 and a second region 142 having a thickness less than the thickness of the first region 141. That is, the region where a part of the upper surface of the p-type semiconductor layer 140 is etched can be the second region 142.

[0036] Each of the first region 141 and the second region 142 can have a shape surrounding the side surface of the active layer 130. Moreover, the first region 141 can be closer to the active layer 130 than the second region 142. That is, the first region 141 can be in contact with the active layer 130 and can surround the side surface of the active layer 130. In addition, the second region 142 can be an outer region of the p-type semiconductor layer 140 and can surround the side surface of the first region 141. The second region 142 can expose a part of the side surface of the first region 141.

[0037] Referring to Figure 8 , a first n-type electrode 151 and a first p-type electrode 161 can be formed.

[0038] The first n-type electrode 151 can be formed on the protrusion 110a of the base layer 110 and the n-type semiconductor layer 120. The central region of the first n-type electrode 151 can be in contact with the protrusion 110a of the base layer 110, and the outer region of the first n-type electrode 151 can be in contact with the n-type semiconductor layer 120.

[0039] The first n-type electrode 151 may completely cover the upper surface of the protrusion 110a of the base layer 110 and may partially cover the upper surface of the n-type semiconductor layer 120. That is, the area of the lower surface of the first n-type electrode 151 may be larger than the area of the upper surface of the protrusion 110a of the base layer 110. In addition, the first n-type electrode 151 may have a cylindrical shape, may be an elliptic cylinder having an elliptical cross-section, or a polyhedron having a polygonal cross-section, but is not limited thereto.

[0040] The first p-type electrode 161 may be formed on the second region 142 of the p-type semiconductor layer 140. The first p-type electrode 161 may have a shape corresponding to the second region 142 of the p-type semiconductor layer 140 and may have an annular shape.

[0041] The area of the first p-type electrode 161 may be smaller than the area of the upper surface of the second region 142 of the p-type semiconductor layer 140. In addition, the side surface of the first p-type electrode 161 may not protrude from the outer surface of the p-type semiconductor layer 140. In addition, the side surface of the first p-type electrode 161 may not contact the side surface of the first region 141 of the p-type semiconductor layer 140. The height of the upper surface of the first p-type electrode 161 may be equal to or lower than the height of the upper surface of the first region 141 of the p-type semiconductor layer 140, but is not limited thereto.

[0042] Each of the first n-type electrode 151 and the first p-type electrode 161 may include a metal material such as Au, W, Pt, Si, Ir, Ag, Cu, Ni, Ti, or Cr and alloys thereof. Alternatively, each of the first n-type electrode 151 and the first p-type electrode 161 may include a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

[0043] Reference Figure 9 , a first protective layer 171 may be formed.

[0044] The first protective layer 171 may cover the entire upper surface of the n-type semiconductor layer 120, the active layer 130, and the p-type semiconductor layer 140. Moreover, the first protective layer 171 may contact the side surface of the first n-type electrode 151 and may expose the upper surface of the first n-type electrode 151. That is, the first protective layer 171 may have an annular shape surrounding the side surface of the first n-type electrode 151. Alternatively, the first protective layer 171 may cover a part of the upper surface of the first n-type electrode 151. Moreover, the thickness of the first protective layer 171 may be smaller than the thickness of the first n-type electrode 151.

[0045] When the first p-type electrode 161 and the first region 141 of the p-type semiconductor layer 140 are spaced apart from each other, the first protective layer 171 may fill the space between the first p-type electrode 161 and the first region 141 of the p-type semiconductor layer 140.

[0046] The first protective layer 171 may be formed of an inorganic insulating material, such as silicon oxide (SiOx), silicon nitride (SiNx), or silicon oxynitride (SiOxNy).

[0047] Referring Figure 10 , the second substrate SUB2 may be fixed to the upper surface of the first n-type electrode 151. The second substrate SUB2 is connected to a device such as a lifter and may be floated on the structure formed by the Figures 1 to 9 process. Then, the first substrate SUB1, the flat portion 110b of the base layer 110, and the mask MASK may be removed.

[0048] In addition, the structure formed by the Figures 1 to 9 process may be inverted so that the second substrate SUB2 may be disposed below the structure formed by the Figures 1 to 9 process. Thus, it may be disposed as shown in Figure 11 .

[0049] Referring Figure 11 , since the first substrate SUB1, the flat portion 110b of the base layer 110, and the mask MASK are removed, the upper surface of the n-type semiconductor layer 120, the upper surface of the active layer 130, and the upper surface of the protruding portion 110a of the base layer 110 may be exposed. Moreover, the upper surface of the protruding portion 110a, the upper surface of the n-type semiconductor layer 120, the upper surface of the active layer 130, and the upper surface of the p-type semiconductor layer 140 may be located on the same plane.

[0050] The n-type semiconductor layer 120 may surround the side surface of the protruding portion 110a of the base layer 110 without covering the top surface of the protruding portion 110a of the base layer 110. In addition, the active layer 130 may surround the side surface of the n-type semiconductor layer 120 without covering the top surface of the n-type semiconductor layer 120. In addition, the p-type semiconductor layer 140 may surround the side surface of the active layer 130 without covering the top surface of the active layer 130.

[0051] Referring Figure 12 , the second n-type electrode 152 and the second p-type electrode 162 may be formed.

[0052] Specifically, as shown in Figure 7 , a part of the upper surface of the p-type semiconductor layer 140 may be etched. Thus, the p-type semiconductor layer 140 may include a first region 141 and a second region 142 having a thickness less than the thickness of the first region 141. That is, the region where a part of the upper surface of the p-type semiconductor layer 140 is etched may be the second region 142. In this case, the second region 142 formed on the upper part of the p-type semiconductor layer 140 and the second region 142 formed on the lower part of the p-type semiconductor layer 140 may overlap.

[0053] In addition, Figure 8 The second n-type electrode 152 and the second p-type electrode 162 may be formed similarly to the process of forming the first n-type electrode 151 and the first p-type electrode 161. Moreover, the first n-type electrode 151 and the second n-type electrode 152 may overlap, and the first p-type electrode 161 and the second p-type electrode 162 may overlap.

[0054] The second n-type electrode 152 may be formed on the protrusion 110a of the base layer 110 and the n-type semiconductor layer 120 . The central region of the second n-type electrode 152 may contact the protrusion 110a of the base layer 110 , and the outer region of the second n-type electrode 152 may contact the n-type semiconductor layer 120 .

[0055] The second n-type electrode 152 may completely cover the upper surface of the protrusion 110a of the base layer 110, and may partially cover the upper surface of the n-type semiconductor layer 120. That is, the area of ​​the lower surface of the second n-type electrode 152 may be greater than the area of ​​the upper surface of the protrusion 110a of the base layer 110. In addition, the second n-type electrode 152 may have a cylindrical shape.

[0056] The second p-type electrode 162 may be formed on the second region 142 of the p-type semiconductor layer 140. The second p-type electrode 162 may have a shape corresponding to the second region 142 of the p-type semiconductor layer 140, and may have a ring shape.

[0057] The area of ​​the second p-type electrode 162 may be smaller than the area of ​​the upper surface of the second region 142 of the p-type semiconductor layer 140. In addition, the side surface of the second p-type electrode 162 may not protrude from the outer surface of the p-type semiconductor layer 140. In addition, the side surface of the second p-type electrode 162 may not contact the side surface of the first region 141 of the p-type semiconductor layer 140. The height of the upper surface of the second p-type electrode 162 may be the same as or similar to the height of the upper surface of the first region 141 of the p-type semiconductor layer 140, but is not limited thereto.

[0058] Each of the second n-type electrode 152 and the second p-type electrode 162 may include a metallic material, such as Au, W, Pt, Si, Ir, Ag, Cu, Ni, Ti, or Cr, and alloys thereof. Alternatively, each of the second n-type electrode 152 and the second p-type electrode 162 may include a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). Moreover, the first n-type electrode 151 and the second n-type electrode 152 (i.e., the first pair of overlapping electrodes) may include the same material, but are not limited thereto. Moreover, the first p-type electrode 161 and the second p-type electrode 162 (i.e., the second pair of overlapping electrodes) may include the same material, but are not limited thereto. Moreover, the first n-type electrode 151 and the second n-type electrode 152, and the first p-type electrode 161 and the second p-type electrode 162 may include different metals, but are not limited thereto.

[0059] Referring to Figure 13 , a second protective layer 172 may be formed, and the second substrate SUB2 may be removed.

[0060] Similar to the process of forming the first protective layer 171 described above, the second protective layer 172 may be formed. Figure 9

[0061] The second protective layer 172 may cover the entire upper surface of the n-type semiconductor layer 120, the active layer 130, and the p-type semiconductor layer 140. Moreover, the second protective layer 172 may contact the side surface of the second n-type electrode 152 and may expose the upper surface of the second n-type electrode 152. That is, the second protective layer 172 may have an annular shape surrounding the side surface of the second n-type electrode 152. Alternatively, the second protective layer 172 may cover a part of the upper surface of the second n-type electrode 152. Moreover, the thickness of the second protective layer 172 may be less than the thickness of the second n-type electrode 152.

[0062] When the second p-type electrode 162 and the second region 142 of the p-type semiconductor layer 140 are spaced apart from each other, the second protective layer 172 may fill the space between the second p-type electrode 162 and the second region 142 of the p-type semiconductor layer 140.

[0063] The second protective layer 172 may be formed of an inorganic insulating material such as silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy), etc. Moreover, the first protective layer 171 and the second protective layer 172 may be formed of the same material, but are not limited thereto.

[0064] Figure 14 is a cross-sectional view of a light-emitting diode 100 according to an embodiment of the present disclosure. That is, Figure 14 is a cross-sectional view taken along line I-I′ of Figure 13 .

[0065] As described above Figures 1 to 13 As described above, the light-emitting diode 100 may include a base layer 110, an n-type semiconductor layer 120, an active layer 130, a p-type semiconductor layer 140, a first n-type electrode 151, a second n-type electrode 152, a first p-type electrode 161 and a second p-type electrode 162, a first protective layer 171 and a second protective layer 172.

[0066] Referring to Figure 14 , the n-type semiconductor layer 120 may be disposed on a side surface of the base layer 110, the active layer 130 may be disposed on a side surface of the n-type semiconductor layer 120, and the p-type semiconductor layer 140 may be disposed on a side surface of the active layer 130. Moreover, the first protective layer 171 may cover a lower surface of the n-type semiconductor layer 120, a lower surface of the active layer 130, and a lower surface of the p-type semiconductor layer 140. Moreover, the second protective layer 172 may cover a top surface of the n-type semiconductor layer 120, a top surface of the active layer 130, and a top surface of the p-type semiconductor layer 140.

[0067] A top surface of the base layer 110, a top surface of the n-type semiconductor layer 120, a top surface of the active layer 130, and a top surface of a first region 141 of the p-type semiconductor layer 140 may be located in the same plane. Additionally, a lower surface of the base layer 110, a lower surface of the n-type semiconductor layer 120, a lower surface of the active layer 130, and a lower surface of the first region 141 of the p-type semiconductor layer 140 may be located in the same plane. Furthermore, a thickness of the base layer 110, a thickness of the n-type semiconductor layer 120, a thickness of the active layer 130, and a thickness of the first region 141 of the p-type semiconductor layer 140 may be the same.

[0068] The first n-type electrode 151 may be disposed on a lower portion of the base layer 110, and the second n-type electrode 152 may be disposed on an upper portion of the base layer 110. Moreover, the first n-type electrode 151 and the second n-type electrode 152 may have the same thickness and may overlap each other. Moreover, the first p-type electrode 161 may be disposed on a lower portion of the p-type semiconductor layer 140, and the second p-type electrode 162 may be disposed on an upper portion of the p-type semiconductor layer 140. Moreover, the first p-type electrode 161 and the second p-type electrode 162 may have the same thickness and may overlap each other.

[0069] Therefore, when a straight line passing through the center C of the base layer 110 and parallel to an upper surface of the base layer 110 is used as a reference line, the light-emitting diode 100 may have a structure symmetric with respect to the reference line. That is, the light-emitting diode 100 of the present disclosure may have a symmetric structure in which an upper structure and a lower structure are the same. Additionally, when a straight line passing through the center C of the base layer 110 and perpendicular to the upper surface of the base layer 110 is used as a reference line, the light-emitting diode 100 may have a structure symmetric with respect to the reference line. For example, when Figure 13When the line I-I' is used as a reference line, the light-emitting diode 100 may have a structure symmetric with respect to the reference line. That is, the light-emitting diode 100 of the present disclosure may have a symmetric structure in which one side structure and the other side structure are substantially the same.

[0070] Generally, in the process of transferring the light-emitting diode 100 to the substrate of the display device, the light-emitting diode may not be accurately transferred to the substrate. For example, the phenomenon of the upper and lower parts of the light-emitting diode being inverted may occur in the transfer process. However, since the upper and lower structures of the light-emitting diode 100 are symmetric, the light-emitting diode 100 of the present disclosure can be stably disposed on the substrate of the display device even when the light-emitting diode 100 is flipped.

[0071] In addition, the present disclosure discloses a structure in which a first n-type electrode 151 and a first p-type electrode 161 are formed in the lower part of the light-emitting diode 100, and a second n-type electrode 152 and a second p-type electrode 162 are formed in the upper part of the light-emitting diode 100. Therefore, even if the light-emitting diode 100 is flipped in the transfer process, the electrodes of the light-emitting diode 100 can be normally connected to the driving element or the power supply line. Therefore, the problem of lighting defects can be reduced.

[0072] Figure 15 is a cross-sectional view of a light-emitting diode according to another embodiment of the present disclosure.

[0073] Compared with Figure 14 Figure 15 shows a structure that is substantially the same except for the structure of the p-type semiconductor layer 140. Therefore, the same reference numerals are used for the same components as those of the light-emitting diode 100 shown in Figure 14 and repeated descriptions are omitted.

[0074] Figure 14 The p-type semiconductor layer 140 of Figure 15 may include a first region 141 in which a partial region is etched and a second region 142 that is not etched, while

[0075] Referring to Figure 15 , no step difference is formed in the upper and lower parts of the p-type semiconductor layer 140, and the thickness of the p-type semiconductor layer 140 may be uniform. The p-type semiconductor layer 140 may be in contact with the active layer 130 and may surround the side surface of the active layer 130. In addition, the upper surfaces of the base layer 110, the n-type semiconductor layer 120, the active layer 130, and the p-type semiconductor layer 140 may be located in the same plane. In addition, the thicknesses of the base layer 110, the n-type semiconductor layer 120, the active layer 130, and the p-type semiconductor layer 140 may be the same. ​

[0076] The first p-type electrode 161 may be disposed on the lower surface of the p-type semiconductor layer 140, and the second p-type electrode 162 may be disposed on the upper surface of the p-type semiconductor layer 140. Moreover, the first p-type electrode 161 and the second p-type electrode 162 may be closer to the outer surface of the p-type semiconductor layer 140 than the inner surface thereof. Moreover, the area of each of the first p-type electrode 161 and the second p-type electrode 162 may be smaller than the areas of the lower surface and the upper surface of the p-type semiconductor layer 140.

[0077] The first protective layer 171 may be in contact with the side surface of the first p-type electrode 161. In addition, the first protective layer 171 may cover a part of the upper surface of the first p-type electrode 161, but is not limited thereto. The second protective layer 172 may be in contact with the side surface of the second p-type electrode 162. In addition, the second protective layer 172 may cover a part of the upper surface of the second p-type electrode 162, but is not limited thereto.

[0078] Figure 16 is a cross-sectional view of a display device according to an embodiment of the present disclosure. Figure 16 shows any one pixel.

[0079] Referring to Figure 16 , a pixel according to an embodiment of the present disclosure may include a light-emitting diode 100, a substrate 200, a buffer layer 210, a thin-film transistor 220, an interlayer insulating layer 230, a first planarization layer 240, a second planarization layer 250, a common voltage line 300, a first connection electrode 410, and a second connection electrode 420.

[0080] The light-emitting diode 100 may have Figures 1 to 15 the structure of the light-emitting diode 100 shown. Figure 16 shows Figure 14 the structure of the light-emitting diode 100 shown.

[0081] The substrate 200 may be formed of glass or plastic, but is not limited thereto. The display device according to an embodiment of the present disclosure may be configured in a top-emission method in which the emitted light is emitted upward. Therefore, as the material of the substrate 200, not only a transparent material but also an opaque material may be used.

[0082] The buffer layer 210 may be disposed on the substrate 200. The buffer layer 210 may reduce or prevent oxygen or hydrogen from infiltrating into the thin-film transistor 220 through the substrate 200. In addition, the buffer layer 210 may be formed of an inorganic insulating material such as silicon oxide (SiOx), silicon nitride (SiNx), or silicon oxynitride (SiOxNy).

[0083] The thin film transistor 220 may be disposed on the substrate 200. The thin film transistor 220 may include a semiconductor layer 221, a gate insulating layer 222, a gate electrode 223, a source electrode 224, and a drain electrode 225.

[0084] The semiconductor layer 221 may be disposed on the buffer layer 210. The semiconductor layer 221 may include a polysilicon semiconductor or an oxide semiconductor. In addition, when the semiconductor layer 221 includes an oxide semiconductor, it may include at least one oxide of indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO), and indium gallium oxide (IGO).

[0085] The gate electrode 223 may be disposed on the semiconductor layer 221. In order to insulate the semiconductor layer 221 from the gate electrode 223, the gate insulating layer 222 may be disposed between the semiconductor layer 221 and the gate electrode 223. The gate insulating layer 222 may be formed of a single layer or multiple layers of silicon nitride (SiNx) or silicon oxide (SiOx). In addition, although Figure 16 a top gate structure in which the gate electrode 223 is disposed on the semiconductor layer 221 is shown, it is not limited thereto. For example, a bottom gate structure in which the semiconductor layer 221 is disposed on the gate electrode 223 may be disclosed.

[0086] The source electrode 224 and the drain electrode 225 may be disposed on the gate electrode 223 while facing each other. The interlayer insulating layer 230 may be disposed between the source electrode 224 and the gate electrode 223 and between the drain electrode 225 and the gate electrode 223. The interlayer insulating layer 230 may be formed of an inorganic insulating material, such as silicon oxide (SiOx), silicon nitride (SiNx), or silicon oxynitride (SiOxNy).

[0087] The common voltage line 300 may be disposed on the interlayer insulating layer 230. The common voltage line 300 may apply a common voltage to the light emitting diode 100. In addition, the common voltage line 300 may be formed of the same material as the source electrode 224 and the drain electrode 225, but it is not limited thereto.

[0088] The light emitting diode 100 may be disposed on the interlayer insulating layer 230, but it is not limited thereto. For example, an insulating layer may be further disposed between the light emitting diode 100 and the thin film transistor 220, and between the light emitting diode 100 and the common voltage line 300.

[0089] The first planarization layer 240 may be disposed on the interlayer insulating layer 230. The first planarization layer 240 may surround the side surface of the light-emitting diode 100. In addition, the first planarization layer 240 may expose portions of the upper surfaces of the second p-type electrode 162 and the second n-type electrode 152 of the light-emitting diode 100. The first n-type electrode 151 of the light-emitting diode 100 may be in contact with the interlayer insulating layer 230. In addition, the first p-type electrode 161 of the light-emitting diode 100 may be covered by the first planarization layer 240.

[0090] The first planarization layer 240 may cover the thin-film transistor 220 and the common voltage line 300. In addition, the first planarization layer 240 may include a first contact hole CH1 exposing a portion of the upper surface of the source electrode 224 of the thin-film transistor 220 and a second contact hole CH2 exposing a portion of the upper surface of the common voltage line 300.

[0091] The first planarization layer 240 may be formed of an organic insulating material such as acrylic resin, epoxy resin, phenolic resin, polyamide resin, or polyimide resin.

[0092] The first connection electrode 410 may be disposed on the first planarization layer 240. Through the first contact hole CH1, the first connection electrode 410 may be electrically connected to the source electrode 224 of the thin-film transistor 220 and may be electrically connected to the second n-type electrode 152.

[0093] The second connection electrode 420 may be disposed on the first planarization layer 240. The second connection electrode 420 may be electrically connected to the common voltage line 300 through the second contact hole CH2.

[0094] Accordingly, the voltage applied to the source electrode 224 of the thin-film transistor 220 may be transmitted to the second n-type electrode 152 through the first connection electrode 410. Moreover, the voltage applied to the common voltage line 300 may be transmitted to the second p-type electrode 162 through the second connection electrode 420. Accordingly, the light-emitting diode 100 may emit light through different voltage levels transmitted from each of the source electrode 224 and the common voltage line 300. The first n-type electrode 151 not electrically connected to the thin-film transistor 220 through the first connection electrode 410 may be floating. In addition, the first p-type electrode 161 not electrically connected to the common voltage line 300 through the second connection electrode 420 may be floating.

[0095] The first connection electrode 41 and the second connection electrode 420 may include a metallic material such as Au, W, Pt, Si, Ir, Ag, Cu, Ni, Ti, or Cr, and alloys thereof. Alternatively, the first connection electrode 410 and the second connection electrode 420 may include a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). Further, the first connection electrode 410 and the second connection electrode 420 may include the same material, but are not limited thereto.

[0096] The second planarization layer 250 may be disposed on the first planarization layer 240. The second planarization layer 250 may cover the upper surface of the light-emitting diode 100. Further, the second planarization layer 250 may fill the interiors of the first contact hole CH1 and the second contact hole CH2. Additionally, the second planarization layer 250 may be formed of the same material as the first planarization layer 240, but is not limited thereto.

[0097] According to the present disclosure, the following advantageous effects can be obtained.

[0098] According to the present disclosure, a plurality of light conversion layers can be formed such that the light efficiency can be improved and the reflectance caused by external light can be reduced.

[0099] It will be apparent to those skilled in the art that the present disclosure above is not limited to the above-described embodiments and drawings, and various substitutions, modifications, and changes can be made to the present disclosure without departing from the spirit or scope of the present disclosure. Accordingly, the scope of the present disclosure is defined by the appended claims, and all changes or modifications derived from the meaning, scope, and equivalent concepts of the claims are intended to fall within the scope of the present disclosure.

[0100] Cross-reference to related applications

[0101] This application claims priority to Korean Patent Application No. 10-2023-0194991, filed on Dec. 28, 2023, which is incorporated herein by reference in its entirety.

Claims

1. A light-emitting diode, the light-emitting diode comprising: A base layer, A first semiconductor layer surrounding a side surface of the base layer, A first electrode on a first surface of the first semiconductor layer, the first electrode being electrically connected to the first semiconductor layer, and A second electrode on a second surface of the first semiconductor layer opposite to the first surface, the second electrode being electrically connected to the first semiconductor layer, wherein the first electrode and the second electrode overlap each other.

2. The light-emitting diode according to claim 1, wherein, The first electrode covers the entire first surface of the base layer; The first electrode covers a partial area of the first surface of the first semiconductor layer; The second electrode covers the entire second surface of the base layer, the second surface of the base layer being opposite to the first surface of the base layer; and The second electrode covers a partial area of the upper surface of the first semiconductor layer.

3. The light emitting diode according to claim 1, wherein, The surface of the base layer and the second surface of the first semiconductor layer are in the same plane.

4. The light-emitting diode according to claim 1, the light-emitting diode further comprising: An active layer surrounding a side surface of the first semiconductor layer; A second semiconductor layer surrounding a side surface of the active layer; A third electrode on a first surface of the second semiconductor layer, the third electrode being electrically connected to the second semiconductor layer; And A fourth electrode on a second surface of the second semiconductor layer opposite to the first surface of the second semiconductor layer, the fourth electrode being electrically connected to the second semiconductor layer, wherein the third electrode and the fourth electrode overlap each other.

5. The light emitting diode according to claim 4, wherein, The second semiconductor layer includes a first region having a first thickness and a second region having a second thickness less than the first thickness, and the first region is between the second region and the active layer.

6. The light emitting diode according to claim 5, wherein, The thickness of the base layer, the thickness of the first semiconductor layer, and the thickness of the first region of the second semiconductor layer are all the same.

7. The light-emitting diode according to claim 5, wherein, The third electrode and the fourth electrode are on the second region.

8. The light emitting diode according to claim 4, wherein, The thickness of the base layer, the thickness of the first semiconductor layer, and the thickness of the second semiconductor layer are all the same.

9. The light-emitting diode according to claim 4, the light-emitting diode further comprising: A first protective layer exposing the first electrode and the third electrode, the first protective layer covering the first surface of the first semiconductor layer, the first surface of the active layer, and the first surface of the second semiconductor layer; And A second protective layer exposing the second electrode and the fourth electrode, the second protective layer covering the second surface of the first semiconductor layer, the second surface of the active layer opposite to the first surface of the active layer, and the second surface of the second semiconductor layer opposite to the first surface of the second semiconductor layer.

10. The light emitting diode according to claim 4, wherein, The first region of the light-emitting diode above the reference line is symmetric to the second region of the light-emitting diode below the reference line, and the reference line passes through the center of the base layer and is parallel to the surface of the base layer.

11. The light-emitting diode according to claim 4, wherein, The first region of the light-emitting diode at the first side of the reference line is symmetric to the second region of the light-emitting diode at the second side of the reference line, and the reference line passes through the center of the base layer and is perpendicular to the surface of the base layer.

12. The light-emitting diode according to claim 1, wherein, The base layer includes an undoped material.

13. The light-emitting diode according to claim 1, wherein, The base layer has a cylindrical shape.

14. A display device, the display device comprising: A common voltage line; A thin-film transistor on a substrate, and A light-emitting diode on the substrate, the light-emitting diode including a first semiconductor layer, a second semiconductor layer surrounding a side surface of the first semiconductor layer, a first electrode electrically connected to the first semiconductor layer, a second electrode electrically connected to the first semiconductor layer, a third electrode electrically connected to the second semiconductor layer, and a fourth electrode electrically connected to the second semiconductor layer, wherein one of the first electrode and the second electrode is electrically connected to the thin-film transistor through a first connection electrode, and one of the third electrode and the fourth electrode is electrically connected to the common voltage line through a second connection electrode.

15. The display device according to claim 14, wherein, The other of the first electrode and the second electrode not electrically connected to the thin-film transistor is floating, and the other of the third electrode and the fourth electrode not electrically connected to the common voltage line is floating.

16. A light-emitting diode, the light-emitting diode comprising: A base layer, the base layer including a first surface and a second surface opposite to the first surface of the base layer; A first semiconductor layer, the first semiconductor layer including a first surface and a second surface opposite to the first surface of the first semiconductor layer, the first semiconductor layer contacting and surrounding a side surface of the base layer, and the first surface of the first semiconductor layer being in the same plane as the first surface of the base layer; An active layer, the active layer including a first surface and a second surface opposite to the first surface of the active layer, the active layer contacting and surrounding a side surface of the first semiconductor layer, and the first surface of the active layer being in the same plane as the first surface of the first semiconductor layer; A second semiconductor layer, the second semiconductor layer including a first surface and a second surface opposite to the first surface of the second semiconductor layer, the second semiconductor layer contacting and surrounding a side surface of the active layer, and the first surface of the second semiconductor layer being in the same plane as the first surface of the active layer; A first pair of overlapping electrodes on the first surface and the second surface of the first semiconductor layer and the first surface and the second surface of the base layer, the first pair of overlapping electrodes being electrically connected to the first semiconductor layer; And A second pair of overlapping electrodes, the second pair of overlapping electrodes being on a first surface and a second surface of the second semiconductor layer, the second pair of overlapping electrodes being electrically connected to the second semiconductor layer.

17. The light-emitting diode according to claim 16, wherein, a first electrode of the first pair of overlapping electrodes is on a first surface of the first semiconductor layer; a second electrode of the first pair of overlapping electrodes is on a second surface of the first semiconductor layer; a first electrode of the second pair of overlapping electrodes is on a first surface of the second semiconductor layer; and a second electrode of the second pair of overlapping electrodes is on a second surface of the second semiconductor layer.

18. The light-emitting diode according to claim 16, wherein, the second surface of the first semiconductor layer and the second surface of the base layer are in the same plane; the second surface of the active layer and the second surface of the first semiconductor layer are in the same plane; and the second surface of the second semiconductor layer and the second surface of the active layer are in the same plane.

19. The light-emitting diode according to claim 16, wherein, a first electrode of the first pair of overlapping electrodes covers the entire first surface of the base layer and a part of the first surface of the first semiconductor layer; a second electrode of the first pair of overlapping electrodes covers the entire second surface of the base layer and a part of the second surface of the first semiconductor layer; a first electrode of the second pair of overlapping electrodes covers a part of the first surface of the second semiconductor layer; and a second electrode of the second pair of overlapping electrodes covers a part of the second surface of the second semiconductor layer.

20. The light emitting diode according to claim 16, wherein, The second semiconductor layer includes a first region having a first thickness and a second region having a second thickness less than the first thickness, and the first region is between the second region and the active layer.

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