Light-emitting diode

Abstract

To provide a light-emitting diode having a plurality of light-emitting units.SOLUTION: A light-emitting diode 1a includes a substrate 10, a buffer layer 20, and at least two light-emitting units. The buffer layer is arranged on the substrate. The at least two light-emitting units are arranged on the buffer layer in a sequentially laminated manner. Each light-emitting unit has a semiconductor light emitting structure 31 and a two-dimensional material layer 32. The two-dimensional material layer is arranged on the semiconductor light emitting structure. The number of the at least two light-emitting units is 2, that is, constituted of a first light-emitting unit 30a and a second light-emitting unit 30b. Each light-emitting unit emits light with a specific wavelength by the semiconductor light emitting structure. A specific wavelength of the light-emitting unit closer to the substrate out of the at least two light-emitting units is a specific wavelength of the light-emitting unit farther from the substrate or more.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a light-emitting diode, and particularly to a light-emitting diode having a plurality of light-emitting units.

Background Art

[0002] In recent years, light-emitting diodes have been widely used for lighting in various fields and products. Currently, a general light-emitting diode converts electrical energy into light energy by the electroluminescence effect by passing an electric current through the junction interface of two different semiconductor materials. As a result, the light-emitting diode not only emits light with high brightness but also obtains energy-saving and power-saving effects.

[0003] Although the wavelength of light can be changed by using different semiconductor materials, most conventional light-emitting diodes can emit only light of a single wavelength by using a single light-emitting structure, which is a limitation in application. There are also light-emitting diodes that combine two light-emitting structures, but in order to combine two light-emitting structures, it is necessary to use materials with similar lattice constants (or emission wavelengths). Similarly, such conventional light-emitting diodes have limitations in structural design and application.

[0004] Therefore, how to design a light-emitting diode that can improve the above-mentioned problems is a research-worthy issue.

Summary of the Invention

[0005] An object of the present invention is to provide a light-emitting diode having a plurality of light-emitting units.

[0006] Another object of the present invention is to provide a light-emitting diode that can emit light of a plurality of wavelengths.

[0007] To achieve the above object, the light-emitting diode according to the present invention includes a substrate, a buffer layer, and at least two light-emitting units. The buffer layer is disposed on the substrate. The at least two light-emitting units are sequentially stacked and disposed on the buffer layer. Each light-emitting unit has a semiconductor light-emitting structure and a two-dimensional material layer. The two-dimensional material layer is disposed on the semiconductor light-emitting structure. Each light-emitting unit emits light of a specific wavelength by the semiconductor light-emitting structure. Among the at least two light-emitting units, the specific wavelength of the light-emitting unit closer to the substrate is equal to or greater than the specific wavelength of the light-emitting unit farther from the substrate.

[0008] In an embodiment of the present invention, the at least two light-emitting units include a first light-emitting unit disposed on the buffer layer and a second light-emitting unit disposed on the two-dimensional material layer of the first light-emitting unit, and the semiconductor light-emitting structure of the first light-emitting unit is different from the semiconductor light-emitting structure of the second light-emitting unit.

[0009] In an embodiment of the present invention, the semiconductor light-emitting structure has a first-type semiconductor epitaxial layer, a light-emitting layer, and a second-type semiconductor epitaxial layer, and the stacking order of the first-type semiconductor epitaxial layer, the light-emitting layer, and the second-type semiconductor epitaxial layer of the first light-emitting unit is opposite to the stacking order of the first-type semiconductor epitaxial layer, the light-emitting layer, and the second-type semiconductor epitaxial layer of the second light-emitting unit.

[0010] In an embodiment of the present invention, the horizontal cross-sectional area of the first light-emitting unit is smaller than the horizontal cross-sectional area of the buffer layer, and the horizontal cross-sectional area of the second light-emitting unit is smaller than the horizontal cross-sectional area of the first light-emitting unit.

[0011] In an embodiment of the present invention, the buffer layer is made of a two-dimensional material.

[0012] In an embodiment of the present invention, the light-emitting diode further includes a base electrode disposed on the buffer layer, and the base electrode is horizontally spaced apart from the at least two light-emitting units.

[0013] In an embodiment of the present invention, each light-emitting unit further has an additional electrode disposed on the two-dimensional material layer, and the additional electrode of each light-emitting unit is horizontally spaced apart from other adjacent light-emitting units.

[0014] In an embodiment of the present invention, the material of the two-dimensional material layer is selected from the group consisting of molybdenum disulfide, tungsten disulfide, molybdenum diselenide, and tungsten diselenide.

[0015] In an embodiment of the present invention, the substrate is made of gallium nitride, sapphire, silicon, or gallium arsenide.

[0016] According to the design of the present invention, the light-emitting diode according to the present invention is designed such that a plurality of light-emitting units are stacked on a single structural member. By controlling the on / off of each light-emitting unit, one or more light-emitting units can be driven to emit light, emitting light of different wavelengths. Also, by using a two-dimensional material for the conductive layer of different light-emitting units, the electron conductivity can be effectively increased, reducing the resistance and driving voltage of the light-emitting units, and it is also possible to combine different light-emitting units with a large difference in lattice constants.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0018] Since each embodiment and example is merely illustrative and not limiting, after referring to this specification, other embodiments and examples can be made by those with ordinary knowledge without departing from the scope of the present invention. According to the following detailed description and claims, the features and advantages of the embodiments of the present invention will become more apparent.

[0019] In this specification, the terms "one" or "a" are used to describe the elements and components described herein. This is for convenience and to give a general meaning to the scope of the present invention. Therefore, unless otherwise indicated, such descriptions are understood to include one or at least one, and the singular form also includes the plural form.

[0020] In this specification, ordinal terms such as "first" and "second" are mainly used to distinguish or refer to the same or similar components and structures, and do not necessarily mean the spatial or temporal ordering of these components and structures. It should be noted that in a specific situation or configuration, the ordinal terms can be used interchangeably without affecting the implementation of the present invention.

[0021] In this specification, the terms "comprising", "having", or other similar terms are directed to non-exclusive inclusion. For example, a component or structure comprising a plurality of elements is not limited only to the elements listed herein, and may include other elements specific to the component or structure that are not explicitly listed.

[0022] FIG. 1 is a schematic diagram showing a light-emitting diode according to the present invention. As shown in FIG. 1, the light-emitting diode 1 according to the present invention includes a substrate 10, a buffer layer 20, and at least two light-emitting units 30. The substrate 10 is a base member of the light-emitting diode 1 of the present invention and is used to mount the buffer layer 20, at least two light-emitting units 30, and other components. In the present invention, the substrate 10 is made of gallium nitride (GaN), sapphire, silicon (Si), or gallium arsenide (GaAs). However, the substrate 10 may be made of other common substrate materials.

[0023] The buffer layer 20 is disposed on the substrate 10. In the present invention, the buffer layer 20 is made of a two-dimensional material. The two-dimensional material referred to here is selected from the group consisting of molybdenum disulfide (MoS2), tungsten disulfide (WS2), molybdenum diselenide (MoSe2), and tungsten diselenide (WSe2). The buffer layer 20 has a stacked structure in which a single atomic layer or a plurality of atomic layers are stacked, but the present invention is not limited thereto. The buffer layer 20 may be other two-dimensional materials having similar properties. The buffer layer 20 can relieve the stress applied to the surface of the substrate 10 and improve the bonding between the substrate 10 and the adjacent light-emitting unit 30. In addition, since the two-dimensional material has high electron conductivity, it can provide good electrical conductivity.

[0024] At least two light-emitting units 30 are sequentially stacked and arranged on the buffer layer 20. That is, except for the light-emitting unit 30 adjacent to the buffer layer 20, the other light-emitting units 30 are provided on another light-emitting unit 30, whereby a plurality of light-emitting units 30 are stacked. In the present invention, the number of light-emitting units 30 is at least two, and may be increased to two or more according to the design. Each light-emitting unit 30 has a semiconductor light-emitting structure 31 and a two-dimensional material layer 32. The semiconductor light-emitting structure 31 is a base member of the light-emitting unit 30 that emits light of a specific wavelength after being conductive. That is, the semiconductor light-emitting structures 31 of each light-emitting unit 30 respectively correspond to specific wavelengths. The specific wavelength varies depending on the material of the semiconductor light-emitting structure 31.

[0025] The two-dimensional material layer 32 of each light-emitting unit 30 is disposed on the semiconductor light-emitting structure 31. The two-dimensional material layer 32 is a stacked structure in which a single atomic layer or a plurality of atomic layers are stacked. The two-dimensional material layer 32 mainly functions as a conductive layer. Since the two-dimensional material has high electron conductivity, it can provide good electrical conductivity and reduce the resistance and driving voltage of adjacent light-emitting units. In addition, the two-dimensional material layer 32 can solve the problem of mismatch of lattice constants that can occur between different materials, and can smoothly combine different light-emitting units with a large difference in lattice constants (or a large difference in emission wavelengths). In the present invention, the material of the two-dimensional material layer 32 is also selected from the group consisting of molybdenum disulfide (MoS2), tungsten disulfide (WS2), molybdenum diselenide (MoSe2), and tungsten diselenide (WSe2). For example, the same two-dimensional material as the buffer layer 20 can be used, but the present invention is not limited thereto.

[0026] In terms of design, among at least two light-emitting units 30, the specific wavelength of the light-emitting unit 30 closer to the substrate 10 is equal to or greater than the specific wavelength of the light-emitting unit 30 farther from the substrate 10. That is, in the plurality of stacked light-emitting units 30, the specific wavelength of the lower light-emitting unit 30 is equal to or greater than the specific wavelength of the upper light-emitting unit 30. When a light-emitting unit 30 is selected and electrically connected to the two-dimensional material layer 32 of the light-emitting unit 30 adjacent below it or electrically connected to the buffer layer 20 adjacent below it, the selected target light-emitting unit 30 emits light of a specific wavelength through its semiconductor light-emitting structure 31. Therefore, the light-emitting diode 1 of the present invention can obtain different light-emitting effects by controlling the on / off of each light-emitting unit 30 and driving the desired single or multiple light-emitting units 30.

[0027] Hereinafter, the light-emitting diode according to the present invention will be described based on the actual structure. FIG. 2 is a schematic diagram showing the light-emitting diode according to the first embodiment of the present invention. As shown in FIG. 2, in this embodiment, the number of at least two light-emitting units of the light-emitting diode 1a according to the present invention is two, that is, it is composed of a first light-emitting unit 30a and a second light-emitting unit 30b. The first light-emitting unit 30a is disposed on the buffer layer 20. The second light-emitting unit 30b is disposed on the first light-emitting unit 30a. In terms of structural design, the horizontal cross-sectional area of the first light-emitting unit 30a is smaller than the horizontal cross-sectional areas of the substrate 10 and the buffer layer 20. Thereby, the entire first light-emitting unit 30a is disposed on the buffer layer 20. The horizontal cross-sectional area of the second light-emitting unit 30b is smaller than the horizontal cross-sectional area of the first light-emitting unit 30a. Thereby, the entire second light-emitting unit 30b is disposed on the first light-emitting unit 30a.

[0028] In this embodiment, the semiconductor light-emitting structure 31 of the first light-emitting unit 30a includes a first-type semiconductor epitaxial layer 311, a light-emitting layer 312, and a second-type semiconductor epitaxial layer 313. The semiconductor light-emitting structure 31 is formed according to the stacking order of the first-type semiconductor epitaxial layer 311, the light-emitting layer 312, and the second-type semiconductor epitaxial layer 313. The semiconductor light-emitting structure 31 of the second light-emitting unit 30b also includes a first-type semiconductor epitaxial layer 311, a light-emitting layer 312, and a second-type semiconductor epitaxial layer 313. However, the semiconductor light-emitting structure 31 of the second light-emitting unit 30b is formed according to the stacking order of the second-type semiconductor epitaxial layer 313, the light-emitting layer 312, and the first-type semiconductor epitaxial layer 311. That is, the stacking order of the epitaxial layers of the semiconductor light-emitting structure 31 of the first light-emitting unit 30a and the semiconductor light-emitting structure 31 of the second light-emitting unit 30b is reversed. For example, if the first-type semiconductor epitaxial layer 311 is an N-type semiconductor epitaxial layer, the light-emitting layer 312 is a multiple quantum well (MQW) layer, and the second-type semiconductor epitaxial layer 313 is a P-type semiconductor epitaxial layer, then the semiconductor light-emitting structure 31 of the first light-emitting unit 30a has an N-MQW-P epitaxial stacking structure, and the semiconductor light-emitting structure 31 of the second light-emitting unit 30b has a P-MQW-N epitaxial stacking structure. However, the present invention is not limited thereto. The epitaxial stacking order of the semiconductor light-emitting structure 31 of the first light-emitting unit 30a and the semiconductor light-emitting structure 31 of the second light-emitting unit 30b may be reversed from the above respectively.

[0029] In this embodiment, the light-emitting diode 1a according to the present invention further includes a base electrode 40. The base electrode 40 is electrically connected to the buffer layer 20. The base electrode 40 is connected to an external power supply via a wire and supplies power to the buffer layer 20. In terms of structural design, the base electrode 40 is disposed on the buffer layer 20. The base electrode 40 is horizontally spaced apart from the first light-emitting unit 30a. The base electrode 40 is made of a metal material, but the present invention is not limited thereto.

[0030] Note that the first light-emitting unit 30a and the second light-emitting unit 30b of the light-emitting diode 1a according to the present invention each have an additional electrode 33. The additional electrode 33 of each light-emitting unit is electrically connected to the two-dimensional material layer 32 of the light-emitting unit. The additional electrode 33 is connected to an external power source via a wire and supplies power to the two-dimensional material layer 32. Due to the structural design, the additional electrode 33 of each light-emitting unit is disposed on the two-dimensional material layer 32 of the light-emitting unit. The additional electrode 33 of the first light-emitting unit 30a is horizontally spaced apart from the adjacent second light-emitting unit 30b. Although the additional electrode 33 is made of a metal material, the present invention is not limited thereto.

[0031] In this embodiment, if the specific wavelength of the first light-emitting unit 30a is λ1 and the specific wavelength of the second light-emitting unit 30b is λ2, then λ1 ≥ λ2. Due to the circuit design, in the light-emitting diode 1a of the present invention, the base electrode 40 is connected to the switch S1 by a lead wire, the additional electrode 33 of the first light-emitting unit 30a is connected to the switch S2 by a lead wire, and the additional electrode 33 of the second light-emitting unit 30b is connected to the switch S3 by a lead wire. When only the switch S1 and the switch S2 are turned on (ON), the light-emitting diode 1a of the present invention emits light with a specific wavelength λ1 by the first light-emitting unit 30a. When only the switch S2 and the switch S3 are turned on, the light-emitting diode 1a of the present invention emits light with a specific wavelength λ2 by the second light-emitting unit 30b. When the switch S1, the switch S2, and the switch S3 are turned on, the light-emitting diode 1a of the present invention emits light with a specific wavelength λ1 + λ2 by the first light-emitting unit 30a and the second light-emitting unit 30b. Table 1 shows the states of each switch and the corresponding light-emitting effects. Therefore, the light-emitting diode 1a of the present invention can obtain the light-emitting effects of light with different wavelengths by driving any one light-emitting unit to emit light alone or driving a plurality of light-emitting units to emit light simultaneously.

Table 1

[0032] FIG. 3 is a schematic diagram showing a light-emitting diode according to a second embodiment of the present invention. As shown in FIG. 3, in this embodiment, the number of at least two light-emitting units of the light-emitting diode 1b according to the present invention is n, that is, it is composed of a first light-emitting unit 30a, a second light-emitting unit 30b, ..., a nth light-emitting unit 30n, and n≥3. The first light-emitting unit 30a is disposed on the buffer layer 20. The second light-emitting unit 30b is disposed on the first light-emitting unit 30a. The nth light-emitting unit 30n is disposed on the (n−1)th light-emitting unit (when n = 3, the (n−1)th light-emitting unit is the second light-emitting unit 30b). In terms of structural design, the horizontal cross-sectional area of the first light-emitting unit 30a is smaller than the horizontal cross-sectional areas of the substrate 10 and the buffer layer 20. Thereby, the entire first light-emitting unit 30a is disposed on the buffer layer 20. The horizontal cross-sectional area of the second light-emitting unit 30b is smaller than the horizontal cross-sectional area of the first light-emitting unit 30a. Thereby, the entire second light-emitting unit 30b is disposed on the first light-emitting unit 30a. The horizontal cross-sectional area of the nth light-emitting unit 30n is smaller than the horizontal cross-sectional area of the (n−1)th light-emitting unit. Thereby, the entire nth light-emitting unit 30n is disposed on the (n−1)th light-emitting unit.

[0033] When the number of light-emitting units is 3 or more, the semiconductor light-emitting structure of any one of the light-emitting units is different from the semiconductor light-emitting structures of the other adjacent light-emitting units. In this embodiment, the semiconductor light-emitting structure 31 of the first light-emitting unit 30a is formed according to the stacking order of the first-type semiconductor epitaxial layer 311, the light-emitting layer 312, and the second-type semiconductor epitaxial layer 313. The semiconductor light-emitting structure 31 of the second light-emitting unit 30b is formed according to the stacking order of the second-type semiconductor epitaxial layer 313, the light-emitting layer 312, and the first-type semiconductor epitaxial layer 311. The semiconductor light-emitting structures of the odd-numbered light-emitting units (for example, the third light-emitting unit, the fifth light-emitting unit,...) after the second light-emitting unit 30b are the same as the semiconductor light-emitting structure 31 of the first light-emitting unit 30a and are formed according to the stacking order of the first-type semiconductor epitaxial layer 311, the light-emitting layer 312, and the second-type semiconductor epitaxial layer 313. The semiconductor light-emitting structures of the even-numbered light-emitting units (for example, the fourth light-emitting unit, the sixth light-emitting unit,...) are the same as the semiconductor light-emitting structure 31 of the second light-emitting unit 30b and are formed according to the stacking order of the second-type semiconductor epitaxial layer 313, the light-emitting layer 312, and the first-type semiconductor epitaxial layer 311. That is, when the number of light-emitting units is 3 or more, the stacking order of the first-type semiconductor epitaxial layer, the light-emitting layer, and the second-type semiconductor epitaxial layer of any one of these light-emitting units is opposite to the stacking order of the first-type semiconductor epitaxial layer, the light-emitting layer, and the second-type semiconductor epitaxial layer of the other adjacent light-emitting units. For example, if all the semiconductor light-emitting structures of the odd-numbered light-emitting units are N-MQW-P epitaxial stacking structures, then all the semiconductor light-emitting structures of the even-numbered light-emitting units will be P-MQW-N epitaxial stacking structures, but the present invention is not limited thereto.

[0034] In this embodiment, the light-emitting diode 1b according to the present invention also further includes a base electrode 40. Since the position of the base electrode 40 is the same as that in the aforementioned first embodiment, the description thereof is omitted. It should be noted that the first light-emitting unit 30a, the second light-emitting unit 30b, …, the nth light-emitting unit 30n of the light-emitting diode 1b according to the present invention each have an additional electrode 33. The additional electrode 33 of each light-emitting unit is electrically connected to the two-dimensional material layer 32 of the light-emitting unit. The additional electrode 33 is connected to an external power source via a wire and supplies power to the two-dimensional material layer 32. In terms of structural design, the additional electrode 33 of each light-emitting unit is disposed on the two-dimensional material layer 32 of the light-emitting unit. The additional electrode 33 of the first light-emitting unit 30a is spaced apart from the second light-emitting unit 30b, …, and the additional electrode of the (n−1)th light-emitting unit is spaced apart from the nth light-emitting unit 30n.

[0035] In this embodiment, assuming that the specific wavelength of the first light-emitting unit 30a is λ1, the specific wavelength of the second light-emitting unit 30b is λ2, …, and the specific wavelength of the nth light-emitting unit 30n is λn, then λ1≧λ2≧…≧λn. In terms of circuit design, for the light-emitting diode 1b of the present invention, the base electrode 40 is connected to the switch S1 by a lead wire, the additional electrode 33 of the first light-emitting unit 30a is connected to the switch S2 by a lead wire, the additional electrode 33 of the second light-emitting unit 30b is connected to the switch S3 by a lead wire, …, and the additional electrode 33 of the nth light-emitting unit 30n is connected to the switch Sn+1 by a lead wire. When only the switch S1 and the switch S2 are turned on, the light-emitting diode 1b of the present invention emits light with a specific wavelength λ1 by the first light-emitting unit 30a. When only the switch S2 and the switch S3 are turned on, the light-emitting diode 1b of the present invention emits light with a specific wavelength λ2 by the second light-emitting unit 30b. When only the switch Sn (when n = 3, the switch Sn is the switch S3) and the switch Sn+1 are turned on, the light-emitting diode 1b of the present invention emits light with a specific wavelength λn by the nth light-emitting unit 30n. When the switch S1, the switch S2, and the switch S3 are turned on, the light-emitting diode 1b of the present invention emits light with a specific wavelength λ1+λ2 by the first light-emitting unit 30a and the second light-emitting unit 30b. When the switch S1, the switch S2, the switch Sn, and the switch Sn+1 are turned on, the light-emitting diode 1b of the present invention emits light with a specific wavelength λ1+λn by the first light-emitting unit 30a and the nth light-emitting unit 30n. When all the switches S1 to Sn+1 are turned on, the light-emitting diode 1b of the present invention emits light with a specific wavelength λ1+λ2+…+λn by the first light-emitting unit 30a to the nth light-emitting unit 30n. Table 2 shows the states of each switch and the corresponding light-emitting effects. Therefore, the light-emitting diode 1b of the present invention can also drive any one light-emitting unit to emit light alone or drive a plurality of light-emitting units to emit light simultaneously to obtain the light-emitting effects of lights with different wavelengths.

Table 2

[0036] The above-described embodiments are merely examples and are not intended to limit the embodiments of the present application or their applications. Further, although at least one exemplary embodiment has been shown in the foregoing embodiments, it should be understood that there can be numerous variations of the present invention. Also, the embodiments described in this specification are not intended to limit the claims, applications, or configurations in any way. Rather, the foregoing embodiments provide a guide for those of ordinary skill in the art to implement one or more of the embodiments. Further, changes can be made to the functions and arrangements of the elements without departing from the scope of the claims, and the scope of the claims includes all known equivalents and all foreseeable equivalents at the time of filing of this patent application.

Explanation of Reference Numerals

[0037] 1, 1a, 1b Light-emitting diodes 10 Substrate 20 Buffer layer 30 Light-emitting unit 30a First light-emitting unit 30b Second light-emitting unit 30n Nth light-emitting unit 31 Semiconductor light-emitting structure 311 First-type semiconductor epitaxial layer 312 Light-emitting layer 313 Second-type semiconductor epitaxial layer 32 Two-dimensional material layer 33 Additional electrode 40 Base electrode S1, S2, S3, Sn+1 Switches

Claims

1. A light-emitting diode, comprising: a substrate; a buffer layer disposed on the substrate; at least two light-emitting units sequentially stacked on the buffer layer, having a semiconductor light-emitting structure and a two-dimensional material layer disposed on the semiconductor light-emitting structure, and emitting light of a specific wavelength by the semiconductor light-emitting structure; Among the at least two light-emitting units, the specific wavelength of the light-emitting unit closer to the substrate is equal to or greater than the specific wavelength of the light-emitting unit farther from the substrate.

2. The at least two light-emitting units include a first light-emitting unit disposed on the buffer layer and a second light-emitting unit disposed on the two-dimensional material layer of the first light-emitting unit, and the semiconductor light-emitting structure of the first light-emitting unit is different from the semiconductor light-emitting structure of the second light-emitting unit. The light-emitting diode according to claim 1.

3. The semiconductor light-emitting structure has a first-type semiconductor epitaxial layer, a light-emitting layer, and a second-type semiconductor epitaxial layer. The stacking order of the first-type semiconductor epitaxial layer, the light-emitting layer, and the second-type semiconductor epitaxial layer of the first light-emitting unit is opposite to the stacking order of the first-type semiconductor epitaxial layer, the light-emitting layer, and the second-type semiconductor epitaxial layer of the second light-emitting unit. The light-emitting diode according to claim 2.

4. The horizontal cross-sectional area of the first light-emitting unit is smaller than the horizontal cross-sectional area of the buffer layer, and the horizontal cross-sectional area of the second light-emitting unit is smaller than the horizontal cross-sectional area of the first light-emitting unit. The light-emitting diode according to claim 2.

5. When the number of the light-emitting units is 3 or more, the semiconductor light-emitting structure of any one of the light-emitting units is different from the semiconductor light-emitting structures of the other adjacent light-emitting units. The light-emitting diode according to claim 1.

6. The semiconductor light-emitting structure has a first-type semiconductor epitaxial layer, a light-emitting layer, and a second-type semiconductor epitaxial layer.

6. The light-emitting diode according to claim 5, wherein the stacking order of the first-type semiconductor epitaxial layer, the light-emitting layer, and the second-type semiconductor epitaxial layer of any one of the light-emitting units is opposite to the stacking order of the first-type semiconductor epitaxial layer, the light-emitting layer, and the second-type semiconductor epitaxial layer of another adjacent light-emitting unit.

7. 2. The light emitting diode of claim 1, wherein the buffer layer is made of a two-dimensional material.

8. a base electrode disposed on the buffer layer; 2. The light-emitting diode of claim 1, wherein the base electrode is horizontally spaced apart from the at least two light-emitting units.

9. Each of the light-emitting units further comprises an additional electrode disposed on the two-dimensional material layer; 2. The light-emitting diode according to claim 1, wherein the additional electrode of each light-emitting unit is horizontally spaced apart from other adjacent light-emitting units.

10. 2. The light-emitting diode of claim 1, wherein the material of the two-dimensional material layer is selected from the group consisting of molybdenum disulfide, tungsten disulfide, molybdenum diselenide, and tungsten diselenide.

11. 10. The light emitting diode of claim 1, wherein the substrate is made of gallium nitride, sapphire, silicon, or gallium arsenide.

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