Light emitting diode and light emitting device

Abstract

The present application relates to the technical field of semiconductor manufacturing, in particular to a light emitting diode, which comprises in sequence from bottom to top: a first semiconductor layer, a superlattice layer, a light emitting layer and a second semiconductor layer; the light emitting diode has a V-shaped pit, the V-shaped pit extends from the superlattice layer to the light emitting layer; the V-shaped pit has an inclined sidewall, the upper and lower ends of the inclined sidewall are defined as a first end point and a second end point respectively; the light emitting layer has a horizontal lower surface; the end point of the horizontal lower surface closest to the inclined sidewall is defined as a third end point, a perpendicular line is drawn through the third end point and perpendicular to the inclined sidewall, the distance from the first end point to the perpendicular line is S1, the distance from the second end point to the perpendicular line is S2, and S1:S2>0.8. By means of the above arrangement, the injected holes can be effectively prevented from leaking into the superlattice layer or the first semiconductor layer, thereby improving the light emitting efficiency of the light emitting diode.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a light-emitting diode and a light-emitting device. Background Technology

[0002] A light-emitting diode (LED) is a semiconductor light-emitting element, typically made of semiconductors such as GaN, GaAs, GaP, and GaAsP. Its core is a PN junction that emits light. LEDs possess advantages such as high luminous intensity, high efficiency, small size, and long lifespan, and are considered one of the most promising light sources available today. LEDs are widely used in lighting, monitoring and command systems, high-definition broadcasting, high-end cinemas, office displays, interactive conferencing, virtual reality, and other fields.

[0003] In recent years, V-pit structures have been commonly designed in the epitaxial structures of nitride LEDs to improve hole injection efficiency. However, the inventors discovered during experiments that current V-pit structures, due to their flawed design, allow a large number of injected holes to tunnel into the superlattice layer or the first semiconductor layer beneath the light-emitting layer, leading to hole leakage and affecting LED luminous performance. Therefore, resolving the balance between improving hole injection efficiency and reducing hole leakage has become a critical challenge for those skilled in the art.

[0004] It should be noted that the information disclosed in this background section is intended only to enhance the understanding of the overall background of the present invention, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] This invention provides a light-emitting diode (LED), which comprises, from bottom to top, a first semiconductor layer, a superlattice layer, a light-emitting layer, and a second semiconductor layer. The LED has a V-shaped pit extending from the superlattice layer to the light-emitting layer; the V-shaped pit has inclined sidewalls, with the upper and lower ends of the inclined sidewalls defined as the first endpoint and the second endpoint, respectively; the light-emitting layer has a horizontal lower surface; the endpoint of the horizontal lower surface closest to the inclined sidewall is defined as the third endpoint, and a perpendicular line is drawn through the third endpoint perpendicular to the inclined sidewall. The distance from the first endpoint to the perpendicular line is S1, and the distance from the second endpoint to the perpendicular line is S2, where S1:S2 > 0.8.

[0006] The present invention also provides a light-emitting diode, which comprises, from bottom to top, a first semiconductor layer, a superlattice layer, a light-emitting layer, and a second semiconductor layer. The light-emitting diode has a V-shaped pit extending from the superlattice layer to the light-emitting layer; the V-shaped pit has inclined sidewalls, with the upper and lower ends of the inclined sidewalls defined as a first endpoint and a second endpoint, respectively; the horizontal plane containing the first endpoint is defined as a first plane, and the horizontal plane containing the second endpoint is defined as a second plane; the light-emitting layer has a horizontal lower surface, and the first plane, the second plane, and the horizontal lower surface are parallel to each other; the distance from the first plane to the horizontal lower surface is H1, and the distance from the second plane to the horizontal lower surface is H2, where H1:H2>1.

[0007] The present invention also provides a light-emitting diode, which comprises, from bottom to top, a first semiconductor layer, a superlattice layer, a light-emitting layer, and a second semiconductor layer. The light-emitting diode has a V-shaped pit extending from the superlattice layer to the light-emitting layer; the V-shaped pit has inclined sidewalls, with the upper and lower ends of the inclined sidewalls defined as a first endpoint and a second endpoint, respectively. The horizontal plane containing the first endpoint is defined as a first plane, and the horizontal plane containing the second endpoint is defined as a second plane. The light-emitting layer has a horizontal lower surface; the endpoint of the horizontal lower surface closest to the inclined sidewall is defined as a third endpoint. A perpendicular line is drawn through the third endpoint, perpendicular to the inclined sidewall. The intersection of the perpendicular line and the inclined sidewall is defined as a first intersection point. The horizontal plane containing the first intersection point is defined as a third plane. The first plane, the second plane, and the third plane are parallel to each other. The distance from the first plane to the third plane is h1, and the distance from the second plane to the third plane is h2, where h1:h2 > 0.8.

[0008] The present invention also provides a light-emitting device, which includes a circuit board and a light-emitting diode, wherein the light-emitting diode is disposed on the circuit board and the light-emitting diode is the light-emitting diode provided in any of the above embodiments.

[0009] The present invention provides a light-emitting diode and a light-emitting device. By adjusting the setting of the ratio of S1 to S2, the ratio of the number of holes injected into the light-emitting layer from the V-shaped pit to the number of holes that may leak into the superlattice layer or the first semiconductor layer through the V-shaped pit is controlled. In other words, by increasing the proportion of holes injected into the light-emitting layer from the V-shaped pit, while effectively preventing holes from leaking into the superlattice layer or the first semiconductor layer, the number of holes entering the light-emitting layer to participate in radiation emission is increased, thereby improving the luminous efficiency of the light-emitting diode.

[0010] Other features and advantages of the present invention will be set forth in the following description, and some of the technical features and advantages may be apparent from the description or learned by practicing the invention. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of the present invention;

[0013] Figure 2A yes Figure 1 A schematic diagram showing the orientation between the V-shaped pit and the light-emitting layer;

[0014] Figure 2B It is a schematic diagram showing the orientation between the straight line containing the horizontal lower surface and the straight line containing the inclined sidewall;

[0015] Figure 2C This is a transmission electron microscope (TEM) image of a light-emitting diode at a V-shaped pit according to an embodiment of the present invention;

[0016] Figure 2D This is a schematic diagram of the structure of a V-shaped pit provided in an embodiment of the present invention;

[0017] Figure 3 This is a schematic diagram of the structure of a light-emitting diode provided in another embodiment of the present invention;

[0018] Figure 4 This is a schematic diagram of the structure of a light-emitting diode provided in another embodiment of the present invention;

[0019] Figure 5A yes Figure 4 A schematic diagram showing the orientation between the V-shaped pit and the light-emitting layer;

[0020] Figure 5B This is a transmission electron microscope (TEM) image of a light-emitting diode at a V-shaped pit according to an embodiment of the present invention;

[0021] Figure 6 This is a schematic diagram of the structure of a light-emitting diode provided in another embodiment of the present invention;

[0022] Figure 7A yes Figure 6 A schematic diagram showing the orientation between the V-shaped pit and the light-emitting layer;

[0023] Figure 7B This is a schematic diagram showing the orientation between the first plane, the second plane, and the third plane;

[0024] Figure 7C This is a transmission electron microscope (TEM) image of a light-emitting diode at a V-shaped pit according to an embodiment of the present invention;

[0025] Figure 8 This is a schematic diagram of the structure of a light-emitting diode provided in another embodiment of the present invention;

[0026] Figure 9 This is a schematic diagram of the structure of a light-emitting diode provided in another embodiment of the present invention.

[0027] Figure label:

[0028] 10-Substrate; 12-First semiconductor layer; 121-U-GaN layer; 122-Stress relief layer; 123-First N-GaN layer; 124-Second N-GaN layer; 125-N-GaN layer; 14-Superlattice layer; 16-Light-emitting layer; 18-Second semiconductor layer; 20-V-shaped pit; 22-Electron blocking layer; 24-Sloping sidewall; 26-Horizontal lower surface; 28-Vertical line; 31-First plane; 32-Second plane; 33-Third plane; A1-First endpoint; A2-Second endpoint; A3- Third endpoint; B1 - Angle between the horizontal lower surface and the inclined sidewall; B2 - Bottom angle; S1 - Distance from the first endpoint to the vertical line; S2 - Distance from the second endpoint to the vertical line; H1 - Distance from the first plane to the horizontal lower surface; H2 - Distance from the second plane to the horizontal lower surface; H3 - Depth of the V-shaped pit; H4 - Injection thickness of the inclined sidewall; H5 - Injection thickness in the vertical direction; W1 - Width of the top opening; Z - Vertical direction; h1 - Distance from the first plane to the third plane; h2 - Distance from the second plane to the third plane. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] In the description of this invention, it should be understood that the terms "center," "lateral," "upper," "lower," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. Additionally, the term "comprising" and any variations thereof mean "at least comprising."

[0031] This invention provides a light-emitting diode (LED), which comprises, from bottom to top, a first semiconductor layer, a superlattice layer, an emissive layer, and a second semiconductor layer. The LED has a V-shaped pit extending from the superlattice layer to the emissive layer. The V-shaped pit has inclined sidewalls, with the upper and lower ends of the inclined sidewalls defined as the first endpoint and the second endpoint, respectively. The emissive layer has a horizontal lower surface. The endpoint of the horizontal lower surface closest to the inclined sidewall is defined as the third endpoint. A perpendicular line is drawn from the third endpoint to the inclined sidewall, with the distance from the first endpoint to the perpendicular line being S1 and the distance from the second endpoint to the perpendicular line being S2, where S1:S2 > 0.8. It is necessary to control the ratio of S1 to S2 within a suitable range to balance hole injection into the emissive layer and hole leakage. Therefore, by controlling S1:S2 > 0.8, hole injection is maximized, increasing the number of holes entering the emissive layer to participate in luminescence, while effectively preventing injected holes from leaking into the superlattice layer or the first semiconductor layer, thereby improving the luminous efficiency of the LED.

[0032] In some embodiments, S1:S2 < 4. Since the thickness of each cycle of the multi-quantum well layer in the light-emitting layer is typically between 80-150 nm, and the mainstream multi-quantum well layer thickness is between 120-150 nm per cycle, if S1:S2 > 4, the size of the V-shaped pit needs to be significantly reduced. This results in insufficient injection space for the V-shaped pit and also increases the driving voltage of the light-emitting diode, causing the overall brightness of the light-emitting diode to be low under high current conditions. If the ratio is too small (e.g., S1:S2 < 0.8), holes will leak into the superlattice layer or the first semiconductor layer, damaging the light-emitting performance of the light-emitting diode.

[0033] In some embodiments, S1 is greater than S2, ensuring that the proportion of holes injected into the light-emitting layer through the V-shaped pits is guaranteed, thereby further improving the light-emitting performance of the light-emitting diode.

[0034] In some embodiments, S1 is the shortest distance from the first endpoint to the perpendicular line, and S2 is the shortest distance from the second endpoint to the perpendicular line.

[0035] In some embodiments, considering that the inclined sidewall is not a perfectly smooth interface in practical applications, the intersection of the vertical line and the inclined sidewall is defined as the first intersection point, and S1 is the distance from the first endpoint to the first intersection point. The intersection of the vertical line and the inclined sidewall is also defined as the first intersection point, and S2 is the distance from the second endpoint to the first intersection point.

[0036] In some embodiments, the width of the top opening of the V-shaped pit is defined as W1, the depth of the V-shaped pit is defined as H3, and the ratio of W1 to H3 ranges from 1 to 2. In some embodiments, H3 ranges from 20 to 800 nm. In some embodiments, W1 ranges from 25 to 1500 nm. This ensures sufficient space for hole injection, thereby increasing the number of holes injected through the V-shaped pit and preventing the driving voltage of the light-emitting diode from increasing, which would cause the brightness of the light-emitting diode to decrease under high current.

[0037] In some embodiments, taking into account material-related properties such as lattice symmetry and surface energy, the bottom angle of the V-shaped pit ranges from 50 to 70°.

[0038] In some embodiments, the longitudinal cross-section of the V-shaped pit is triangular or triangular-like. Considering factors such as actual process conditions in practical applications, such as the inclined sidewalls not being perfectly smooth interfaces, the longitudinal cross-section of the V-shaped pit of the present invention is not limited to a triangle, but can be a triangular-like structure close to a triangle.

[0039] In some embodiments, the first semiconductor layer includes an N-GaN layer; or, the first semiconductor layer sequentially includes a U-GaN layer, a first N-GaN layer, a stress-relieving layer, and a second N-GaN layer in a bottom-up direction. In some embodiments, the second semiconductor layer includes a P-GaN layer.

[0040] In some embodiments, an electron blocking layer is further included between the second semiconductor layer and the light-emitting layer, with V-shaped pits extending into the electron blocking layer. The electron blocking layer 22 can be provided to prevent electron leakage from the light-emitting layer 16, further improving luminous efficiency.

[0041] In some embodiments, the first end point is located at the top opening of the V-shaped pit, and the second end point is located at the bottom of the V-shaped pit.

[0042] In some embodiments, the angle between the horizontal lower surface of the light-emitting layer and the inclined sidewall of the V-shaped pit is less than or equal to 90°.

[0043] This invention also provides a light-emitting diode (LED), which comprises, from bottom to top, a first semiconductor layer, a superlattice layer, an emissive layer, and a second semiconductor layer. The LED has a V-shaped pit extending from the superlattice layer to the emissive layer. The V-shaped pit has inclined sidewalls, with the upper and lower ends of the inclined sidewalls defined as a first endpoint and a second endpoint, respectively. The horizontal plane containing the first endpoint is defined as a first plane, and the horizontal plane containing the second endpoint is defined as a second plane. The emissive layer has a horizontal lower surface, and the first plane, the second plane, and the horizontal lower surface are parallel to each other. The distance from the first plane to the horizontal lower surface is H1, and the distance from the second plane to the horizontal lower surface is H2, where H1:H2 > 1. It is necessary to control the ratio of H1 to H2 within a suitable range to balance the issues of hole injection into the emissive layer and hole leakage. Therefore, by controlling H1:H2 > 1, hole injection is maximized, increasing the number of holes entering the emissive layer to participate in radiative emission, while effectively preventing injected holes from leaking into the superlattice layer or the first semiconductor layer, thereby improving the luminous efficiency of the LED.

[0044] In some embodiments, H1:H2 < 5.5. If the ratio is too large (e.g., H1:H2 > 5.5), it will not only result in insufficient injection space for the V-shaped pit, but also increase the driving voltage of the LED, causing the overall brightness of the LED to be low under high current conditions. If the ratio is too small (e.g., H1:H2 < 1), it will cause holes to leak into the superlattice layer or the first semiconductor layer, damaging the performance of the LED.

[0045] In some embodiments, H1 is the shortest distance from the first plane to the horizontal lower surface, and H2 is the shortest distance from the second plane to the horizontal lower surface.

[0046] This invention also provides a light-emitting diode (LED), which comprises, from bottom to top, a first semiconductor layer, a superlattice layer, an emissive layer, and a second semiconductor layer. The LED has a V-shaped pit extending from the superlattice layer to the emissive layer. The V-shaped pit has inclined sidewalls, with the upper and lower ends of the inclined sidewalls defined as the first endpoint and the second endpoint, respectively. The horizontal plane containing the first endpoint is defined as the first plane, and the horizontal plane containing the second endpoint is defined as the second plane. The emissive layer has a horizontal lower surface. The endpoint of the horizontal lower surface closest to the inclined sidewall is defined as the third endpoint. A perpendicular line is drawn from the third endpoint to the inclined sidewall, and the intersection of this perpendicular line and the inclined sidewall is defined as the first intersection point. The horizontal plane containing the first intersection point is defined as the third plane. The first, second, and third planes are parallel to each other. The distance from the first plane to the third plane is h1, and the distance from the second plane to the third plane is h2, where h1:h2 > 0.8. It is necessary to control the ratio of h1 to h2 within a suitable range to balance the issues of hole injection into the emissive layer and hole leakage. Therefore, by controlling h1:h2 > 0.8, hole injection can be maximized, increasing the number of holes entering the light-emitting layer to participate in radiative emission. At the same time, it can effectively prevent injected holes from leaking into the superlattice layer or the first semiconductor layer, thereby improving the luminous efficiency of the light-emitting diode.

[0047] In some embodiments, h1:h2 < 4. If the ratio is too large (e.g., h1:h2 > 4), it will not only result in insufficient injection space for the V-shaped pit, but also increase the driving voltage of the LED, causing the overall brightness of the LED to be low under high current conditions. If the ratio is too small (e.g., h1:h2 < 0.8), it will cause holes to leak into the superlattice layer or the first semiconductor layer, damaging the performance of the LED.

[0048] In some embodiments, h1 is greater than h2 to ensure that the proportion of holes injected into the light-emitting layer through the V-shaped pits is guaranteed, thereby further improving the light-emitting performance of the light-emitting diode.

[0049] The present invention also provides a light-emitting device, which includes a circuit board and a light-emitting diode, wherein the light-emitting diode is disposed on the circuit board and the light-emitting diode is the light-emitting diode provided in any of the above embodiments.

[0050] Please see Figure 1 , Figure 2A , Figure 2B and Figure 2C , Figure 1 This is a schematic diagram of the structure of a light-emitting diode provided in an embodiment of the present invention. Figure 2A yes Figure 1 A schematic diagram showing the orientation between the V-shaped pit 20 and the light-emitting layer 16. Figure 2B This is a schematic diagram showing the orientation between the straight line containing the horizontal lower surface 26 and the straight line containing the inclined sidewall 24; Figure 2CThis is a transmission electron microscope (TEM) image of a light-emitting diode at the V-shaped pit 20 according to an embodiment of the present invention. To achieve at least one or more of the aforementioned advantages, an embodiment of the present invention provides a light-emitting diode. As shown in the figure, the light-emitting diode may sequentially include, from bottom to top: a first semiconductor layer 12, a superlattice layer 14, a light-emitting layer 16, and a second semiconductor layer 18.

[0051] A first semiconductor layer 12 may be disposed on a substrate 10. The substrate 10 may be an insulating substrate, preferably made of a transparent or translucent material. In the illustrated embodiment, the substrate 10 is a sapphire substrate. In some embodiments, the substrate 10 may be a patterned sapphire substrate, but the invention is not limited thereto. The substrate 10 may also be made of a conductive or semiconductor material. For example, the substrate 10 material may include at least one of silicon carbide, silicon, magnesium aluminum oxide, magnesium oxide, lithium aluminum oxide, aluminum gallium oxide, and gallium nitride.

[0052] The first semiconductor layer 12 may be an N-type semiconductor layer, which can provide electrons to the light-emitting layer 16 under the influence of a power source. In some embodiments, the first semiconductor layer 12 includes an N-type doped nitride layer. The N-type doped nitride layer may include N-type impurities. N-type impurities may include one or a combination of Si, Ge, and Sn. In some embodiments, the first semiconductor layer 12 may include an N-GaN layer.

[0053] The light-emitting layer 16 can be a quantum well (QW) structure. In some embodiments, the light-emitting layer 16 can also be a multiple quantum well (MQW) structure, such as a GaN / AlGaN, InAlGaN / InAlGaN, or InGaN / AlGaN multi-quantum-well structure. Furthermore, the composition and thickness of the well layers within the light-emitting layer 16 determine the wavelength of the generated light. To improve the luminous efficiency of the light-emitting layer 16, this can be achieved by changing the depth of the quantum wells, the number of paired quantum wells and quantum barriers, the thickness, and / or other characteristics within the light-emitting layer 16.

[0054] During the growth of a light-emitting diode (LED), numerous defects such as dislocations are generated. Some of these dislocations extend along the growth direction, penetrating the entire LED structure. When a dislocation enters the superlattice layer 14, by controlling the growth conditions of the superlattice layer 14, V-shaped pits 20 nucleate and grow at the penetrating dislocation sites, releasing stress. The material of the superlattice layer 14 may include In. x Ga (1-x) N / GaN (0 < x < 1).

[0055] The second semiconductor layer 18 can be a P-type semiconductor layer, which can provide holes to the light-emitting layer 16 under power. In some embodiments, the second semiconductor layer 18 includes a P-type doped nitride layer. The P-type doped nitride layer may include one or more P-type impurities. The P-type impurities may include one or a combination of Mg, Zn, and Be. The second semiconductor layer 18 can be a single-layer structure or a multi-layer structure with different compositions.

[0056] The light-emitting diode (LED) has a V-shaped pit 20 extending from the superlattice layer 14 towards the light-emitting layer 16. The V-shaped pit 20 originates from the superlattice layer 14 and extends upwards to the lower boundary of the light-emitting layer 16 or the second semiconductor layer 18. In some embodiments, the V-shaped pit 20 may refer to the pit-like structure closest to the second semiconductor layer 18. The V-shaped pit 20 has inclined sidewalls 24, with the upper and lower ends defined as a first endpoint A1 and a second endpoint A2, respectively. The first endpoint A1 is located at the top opening of the V-shaped pit 20, and the second endpoint A2 is located at the bottom of the V-shaped pit 20. The light-emitting layer 16 has a horizontal lower surface 26. This horizontal lower surface 26 may refer to the lower surface of the MQW barrier layer. The horizontal lower surface 26 refers to the lowest horizontal surface of the light-emitting layer 16, closest to the superlattice layer 14. In other words, the recessed portion of the light-emitting layer 16 does not belong to the horizontal lower surface 26, and the angle B1 between the horizontal lower surface 26 and the inclined sidewall 24 is less than or equal to 90°. Regarding the angle B1, as follows... Figure 2B As shown, the angle B1 is the angle between the straight line containing the horizontal lower surface 26 and the straight line containing the inclined sidewall 24 from a longitudinal cross-sectional view. This angle B1 is the acute angle, and optionally, it ranges from 30° to 70°. The endpoint of the horizontal lower surface 26 closest to the inclined sidewall 24 is defined as the third endpoint A3. A perpendicular line 28 is drawn from the third endpoint A3, perpendicular to the inclined sidewall 24. This perpendicular line 28 can be a straight line. The distance from the first endpoint A1 to the perpendicular line 28 is S1, and the distance from the second endpoint A2 to the perpendicular line 28 is S2. It should be noted that these definitions refer to the longitudinal cross-sectional view of the light-emitting diode, and are illustrated using a pair of adjacent inclined sidewalls 24 and horizontal lower surfaces 26, as shown in the figure, with the inclined sidewall 24 on the right and the horizontal lower surface 26 on the right as examples.

[0057] During the research, it was found that hole injection occurs from both the direction perpendicular to the inclined sidewall 24 of the V-shaped pit 20 and the vertical direction Z. Since the injection thickness H4 perpendicular to the inclined sidewall 24 of the V-shaped pit 20 is often smaller than the injection thickness H5 in the vertical direction Z, the lateral injection efficiency is much higher than the vertical direction Z injection efficiency. Furthermore, considering that holes laterally injected from the S1 region are primarily transported to the light-emitting layer 16, which is beneficial for light emission, while holes laterally injected from the S2 region can tunnel into the superlattice layer 14 or the first semiconductor layer 12, leading to hole leakage and negatively impacting the performance of the light-emitting diode (LED), increasing the S1 region improves the LED's light-emitting performance. However, if the ratio of S1 to S2 is too large, the V-shaped pit 20 will be too small, resulting in insufficient space for hole injection from the V-shaped pit 20. Therefore, it is necessary to control the ratio of S1 to S2 within a suitable range to balance the issues of hole injection into the light-emitting layer 16 and hole leakage. Therefore, this embodiment maximizes hole injection by controlling S1:S2 > 0.8, while effectively preventing injected holes from leaking into the superlattice layer 14 or the first semiconductor layer 12, thereby improving the luminous efficiency of the LED. Optionally, S1:S2 < 4, or less than 4.2, 4.4, 4.5, or 5. If the ratio is too large (e.g., S1:S2 > 4, 4.2, 4.4, or 5), it will not only result in insufficient injection space for the V-shaped pit 20, but also increase the driving voltage of the LED, causing the overall brightness of the LED to be low under high current conditions. If the ratio is too small (e.g., S1:S2 < 0.8), it will cause holes to leak into the superlattice layer 14 or the first semiconductor layer 12, damaging the performance of the LED. Optionally, S1 is greater than S2, i.e., S1:S2 > 1, to further improve the luminous performance of the LED. Optionally, S1:S2 > 1.1, 1.2, or 1.5.

[0058] S1 is the shortest distance from the first endpoint A1 to the perpendicular line 28, and S2 is the shortest distance from the second endpoint A2 to the perpendicular line 28. However, this design is not limited to this. Considering that in practical applications, the inclined sidewall 24 is not a perfectly smooth interface, the intersection of the perpendicular line 28 and the inclined sidewall 24 can be defined as the first intersection point, and S1 is the distance from the first endpoint A1 to the first intersection point. The intersection of the perpendicular line 28 and the inclined sidewall 24 is defined as the first intersection point, and S2 is the distance from the second endpoint A2 to the first intersection point.

[0059] In some embodiments, such as Figure 2C As shown in the transmission electron microscope (TEM image), the corresponding positions of the V-shaped pit 20, the inclined sidewall 24, the first endpoint A1, the second endpoint A2, the third endpoint A3, S1, S2, the horizontal lower surface 26, and the vertical line 28 are indicated.

[0060] In some embodiments, such as Figure 2DAs shown, the width of the top opening of the V-shaped pit 20 is defined as W1, and the depth of the V-shaped pit 20 is defined as H3. Due to material-related properties such as lattice symmetry and surface energy, the bottom included angle B2 of the V-shaped pit 20 is typically between 50° and 70°, and is usually 60°. Optionally, the ratio of W1 to H3 ranges from 1 to 2. H3 ranges from 20 to 800 nm, and W1 ranges from 25 to 1500 nm. This ensures sufficient space for hole injection, thereby increasing the number of holes injected through the V-shaped pit 20 and preventing the driving voltage of the light-emitting diode from increasing, which would cause the brightness of the light-emitting diode to decrease under high current. The longitudinal cross-section of the V-shaped pit 20 is triangular or triangular-like. It should be noted that, considering factors such as actual process conditions in practical applications, such as the inclined sidewall 24 not being a completely smooth interface, the longitudinal cross-section of the V-shaped pit 20 of this invention is not limited to a triangle, but can be a triangular-like shape. Optionally, the longitudinal section of the V-shaped pit 20 is an equilateral triangle.

[0061] In some embodiments, such as Figure 3 As shown, an electron blocking layer 22 may also be included between the second semiconductor layer 18 and the light-emitting layer 16, with the V-shaped pit 20 extending to the electron blocking layer 22. The electron blocking layer 22 is provided to prevent electron leakage from the light-emitting layer 16, further improving luminous efficiency. The electron blocking layer 22 can be a single-layer AlGaN structure, an AlGaN / GaN superlattice structure, an AlGaN / InGaN superlattice structure, or an AlGaN / InGaN / GaN superlattice structure, and can be partially doped with Mg, fully doped with Mg, or undoped. At the electron blocking layer 22, the V-shaped pit 20 attached below it will also form a similar pit shape, and the shape, size, and other specifications of this pit can be referenced to the specifications of the V-shaped pit 20. It should be noted that, similarly, in the longitudinal direction of the V-shaped pit 20, the shapes of other pits are also the same as the specifications of the V-shaped pit 20, such as the pit located at the superlattice layer 14. The first semiconductor layer 12 may include an N-GaN layer 125 and a U-GaN layer 121, with the U-GaN layer 121 located between the substrate 10 and the N-GaN layer 125. The second semiconductor layer 18 may include a P-GaN layer.

[0062] Please see Figure 4 and Figure 5A , Figure 4 This is a schematic diagram of the structure of a light-emitting diode provided in another embodiment of the present invention. Figure 5A yes Figure 4 A schematic diagram showing the orientation between the V-shaped pit 20 and the light-emitting layer 16. As shown in the figure, another embodiment of the present invention provides a light-emitting diode, which includes, in a bottom-up direction, a first semiconductor layer 12, a superlattice layer 14, a light-emitting layer 16, and a second semiconductor layer 18.

[0063] The light-emitting diode (LED) has a V-shaped pit 20 extending from the superlattice layer 14 to the light-emitting layer 16. The V-shaped pit 20 has inclined sidewalls 24, with the upper and lower ends of the inclined sidewalls 24 defined as a first endpoint A1 and a second endpoint A2, respectively. The horizontal plane containing the first endpoint A1 is defined as a first plane 31, and the horizontal plane containing the second endpoint A2 is defined as a second plane 32. The light-emitting layer 16 has a horizontal lower surface 26, and the first plane 31, the second plane 32, and the horizontal lower surface 26 are parallel to each other. The angle B1 between the horizontal lower surface 26 and the inclined sidewalls 24 ranges from 30° to 70°. The distance from the first plane 31 to the horizontal lower surface 26 is H1, and the distance from the second plane 32 to the horizontal lower surface 26 is H2. It should be noted that these definitions refer to the definition from the perspective of the longitudinal section of the LED, and are illustrated using a pair of inclined sidewalls 24 and horizontal lower surfaces 26 that are closest to each other; that is, the inclined sidewall 24 on the right and the horizontal lower surface 26 on the right are used as examples in the figure.

[0064] During the research, it was found that hole injection occurs from both the direction perpendicular to the inclined sidewall 24 of the V-shaped pit 20 and the vertical direction Z. Since the injection thickness H4 perpendicular to the inclined sidewall 24 of the V-shaped pit 20 is often less than the injection thickness H5 in the vertical direction Z, the lateral injection efficiency is much higher than the vertical direction Z injection efficiency. Therefore, this embodiment maximizes hole injection by controlling H1:H2 > 1, while effectively preventing injected holes from leaking into the superlattice layer 14 or the first semiconductor layer 12, thereby improving the luminous efficiency of the light-emitting diode. Optionally, H1:H2 > 1.1, 1.2, 1.5, etc., further improving the luminous brightness. Optionally, H1:H2 < 5.5, or less than 5.7, 6, 6.2, 6.5. If the ratio is too large (e.g., H1:H2 > 5.5, 5.7, 6, 6.5, etc.), it will not only result in insufficient injection space in the V-shaped pit 20, but also increase the driving voltage of the light-emitting diode, causing the overall brightness of the light-emitting diode to be low under high current conditions. If the ratio is too small (e.g., H1:H2 < 1), it will cause holes to leak into the superlattice layer 14 or the first semiconductor layer 12, damaging the performance of the light-emitting diode.

[0065] In some embodiments, H1 is the shortest distance from the first plane 31 to the horizontal lower surface 26, and H2 is the shortest distance from the second plane 32 to the horizontal lower surface 26. In some embodiments, H1 is the shortest vertical distance from the first plane 31 to the horizontal lower surface 26, and H2 is the shortest vertical distance from the second plane 32 to the horizontal lower surface 26.

[0066] In some embodiments, such as Figure 5BAs shown in the transmission electron microscope (TEM image), the corresponding positions of the V-shaped pit 20, the inclined sidewall 24, the first endpoint A1, the second endpoint A2, H1, H2, the horizontal lower surface 26, the first plane 31, and the second plane 32 are illustrated.

[0067] Please see Figure 6 , Figure 7A and Figure 7B , Figure 6 This is a schematic diagram of the structure of a light-emitting diode provided in another embodiment of the present invention. Figure 7A yes Figure 6 A schematic diagram showing the orientation between the V-shaped pit 20 and the light-emitting layer 16. Figure 7B This is a schematic diagram showing the orientation between the first plane 31, the second plane 32, and the third plane 33. Another embodiment of the present invention provides a light-emitting diode. As shown in the figure, the light-emitting diode may sequentially include, from bottom to top: a first semiconductor layer 12, a superlattice layer 14, a light-emitting layer 16, and a second semiconductor layer 18.

[0068] The light-emitting diode (LED) has a V-shaped pit 20 extending from the superlattice layer 14 towards the light-emitting layer 16. The V-shaped pit 20 originates from the superlattice layer 14 and extends upwards to the lower boundary of the light-emitting layer 16 or the second semiconductor layer 18. The V-shaped pit 20 has inclined sidewalls 24, with the upper and lower ends defined as a first endpoint A1 and a second endpoint A2, respectively. The horizontal plane containing the first endpoint A1 is defined as a first plane 31, and the horizontal plane containing the second endpoint A2 is defined as a second plane 32. The light-emitting layer has a horizontal lower surface 26, which is the lowest horizontal surface of the light-emitting layer 16, closest to the superlattice layer 14. In other words, the pit portion of the light-emitting layer 16 does not belong to this horizontal lower surface 26, and the angle between the horizontal lower surface 26 and the inclined sidewalls 24 is less than or equal to 90°. Define the endpoint of the horizontal lower surface 26 closest to the inclined sidewall 24 as the third endpoint A3. Draw a perpendicular line 28 through the third endpoint A3, perpendicular to the inclined sidewall 24. This perpendicular line 28 can be a straight line. The intersection of the perpendicular line 28 and the inclined sidewall 24 is the first intersection point. The horizontal plane containing the first intersection point is the third plane 33. The first plane 31, the second plane 32, and the third plane 33 are parallel to each other (the first plane 31, the second plane 32, and the third plane 33 are all indicated by dashed lines in the figure). The distance from the first plane 31 to the third plane 33 is h1, and the distance from the second plane 32 to the third plane 33 is h2. It should be noted that these definitions refer to the definition description from the perspective of the longitudinal section of the light-emitting diode, and are described using a set of inclined sidewalls 24 and horizontal lower surfaces 26 that are closest to each other, that is, the inclined sidewall 24 on the right and the horizontal lower surface 26 on the right are used as examples in the figure.

[0069] During the research, it was found that hole injection occurs from both the direction perpendicular to the inclined sidewall 24 of the V-shaped pit 20 and the vertical direction Z. Since the injection thickness H4 perpendicular to the inclined sidewall 24 of the V-shaped pit 20 is often less than the injection thickness H5 in the vertical direction Z, the lateral injection efficiency is much higher than the vertical direction Z injection efficiency. Therefore, this embodiment maximizes hole injection by controlling h1:h2 > 0.8, while effectively preventing injected holes from leaking into the superlattice layer 14 or the first semiconductor layer 12, thereby improving the luminous efficiency of the light-emitting diode. Optionally, h1:h2 < 4, or less than 4.2, 4.4, 4.5, or 5. If the ratio is too large (e.g., h1:h2 > 4, 4.2, 4.4, 5, etc.), it will not only result in insufficient injection space for the V-shaped pit 20, but also increase the driving voltage of the LED, causing the overall brightness of the LED to be low under high current conditions. If the ratio is too small (e.g., h1:h2 < 0.8), it will cause holes to leak into the superlattice layer 14 or the first semiconductor layer 12, damaging the performance of the LED. Optionally, h1 is greater than h2, i.e., h1:h2 > 1, to further improve the luminous performance of the LED. Optionally, h1:h2 > 1.1, 1.2, 1.5, etc.

[0070] In some embodiments, such as Figure 7C As shown, the corresponding positions of the V-shaped pit 20, inclined sidewall 24, first endpoint A1, second endpoint A2, third endpoint A3, h1, h2, horizontal lower surface 26, first plane 31, second plane 32, third plane 33 and vertical line 28 are shown in the transmission electron microscope (TEM image).

[0071] Please see Figure 8 , Figure 8 This is a schematic diagram of the structure of a light-emitting diode provided in another embodiment of the present invention. Compared to Figure 1The main difference in this embodiment of the light-emitting diode is that the first semiconductor layer 12 in this embodiment sequentially includes a U-GaN layer 121, a first N-GaN layer 123, a stress relief layer 122, and a second N-GaN layer 124 from bottom to top. That is, the stress relief layer 122 is located between the two N-GaN layers. In some embodiments, the stress relief layer 122 can be a superlattice structure. By providing the second N-GaN layer 124 on the stress relief layer 122, the electrostatic discharge resistance of the light-emitting diode can be improved, and the series resistance can be reduced. In some embodiments, the first semiconductor layer 12 can also sequentially include a U-GaN layer 121, an N-GaN layer 125, a stress relief layer 122, and a U-GaN layer 121 from bottom to top. In addition, by controlling the growth conditions of the N-GaN layer, the size of the V-shaped pit can be quickly controlled, and the crystal quality of the subsequent connection growth layer can be improved. The V-shaped pit 20 can also originate from the stress relief layer 14 and extend upwards to the lower boundary of the light-emitting layer 16 or the second semiconductor layer 18.

[0072] Please see Figure 9 , Figure 9 This is a schematic diagram of the structure of a light-emitting diode provided in another embodiment of the present invention. Compared to Figure 8 The main difference in this embodiment of the light-emitting diode is that the V-shaped pit structure located at the stress relief layer 122 does not extend downward into the first N-GaN layer 123.

[0073] The present invention also provides a light-emitting device, which includes a circuit board and a light-emitting diode, wherein the light-emitting diode is disposed on the circuit board and the light-emitting diode is the light-emitting diode provided in any of the above embodiments.

[0074] An embodiment of the present invention provides a light-emitting diode and a light-emitting device. By adjusting the setting of the ratio of S1 to S2, the injected holes can be effectively prevented from leaking into the superlattice layer 14 or the first semiconductor layer 12, thereby improving the light-emitting efficiency of the light-emitting diode.

[0075] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of the present invention can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or the background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light emitting diode, characterized by: The light emitting diode comprises, in sequence from bottom to top, a first semiconductor layer, a superlattice layer, a light emitting layer, and a second semiconductor layer. The light emitting diode has a V-shaped pit extending from the superlattice layer to the light emitting layer; the V-shaped pit has an inclined side wall, and the upper and lower ends of the inclined side wall are defined as a first end point and a second end point, respectively; the light emitting layer has a horizontal lower surface; the end point of the horizontal lower surface closest to the inclined side wall is defined as a third end point, a perpendicular line is drawn through the third end point and perpendicular to the inclined side wall, the distance from the first end point to the perpendicular line is S1, the distance from the second end point to the perpendicular line is S2, and S1:S2>0.

8. S1 is the shortest distance from the first end point to the perpendicular line, and S2 is the shortest distance from the second end point to the perpendicular line; the first end point is located at the top opening of the V-shaped pit, and the second end point is located at the bottom of the V-shaped pit.

2. The light emitting diode of claim 1, wherein: S1:S2<4.

3. The light emitting diode of claim 1, wherein: S1 is greater than S2.

4. The light emitting diode of claim 1, wherein: The first semiconductor layer comprises a U-GaN layer and an N-GaN layer.

5. The light emitting diode of claim 1, wherein: The width of the top opening of the V-shaped pit is defined as W1, and the depth of the V-shaped pit is defined as H3, and the ratio of W1 to H3 ranges from 1 to 2.

6. The light emitting diode of claim 5, wherein: H3 ranges from 20 to 800 nm.

7. The light emitting diode of claim 5, wherein: W1 ranges from 25 to 1500 nm.

8. The light emitting diode of claim 1, wherein: The bottom angle of the V-shaped pit ranges from 50 to 70°.

9. The light emitting diode of claim 1, wherein: The longitudinal cross section of the V-shaped pit is triangular or quasi-triangular.

10. The light emitting diode of claim 1, wherein: The first semiconductor layer comprises an N-GaN layer.

11. The light emitting diode of claim 1, wherein: The first semiconductor layer comprises, in sequence from bottom to top, a U-GaN layer, a first N-GaN layer, a stress release layer, and a second N-GaN layer; or, the first semiconductor layer comprises, in sequence from bottom to top, a U-GaN layer, an N-GaN layer, a stress release layer, and a U-GaN layer.

12. The light emitting diode of claim 11, wherein: The stress release layer is a superlattice structure.

13. The light emitting diode of claim 1, wherein: The second semiconductor layer comprises a P-GaN layer.

14. The light emitting diode of claim 1, wherein: The light emitting diode further comprises an electron blocking layer between the second semiconductor layer and the light emitting layer, and the V-shaped pit extends to the electron blocking layer.

15. The light emitting diode of claim 1, wherein: The angle between the horizontal lower surface and the inclined side wall is less than or equal to 90°.

16. A light emitting diode, comprising: The light emitting diode comprises, in sequence from bottom to top, a first semiconductor layer, a superlattice layer, a light emitting layer, and a second semiconductor layer. The light emitting diode has a V-shaped pit extending from the superlattice layer to the light emitting layer; the V-shaped pit has an inclined side wall, the upper and lower ends of the inclined side wall are respectively a first end point and a second end point, the horizontal plane where the first end point is located is a first plane, the horizontal plane where the second end point is located is a second plane, and the light emitting layer has a horizontal lower surface; the end point of the horizontal lower surface closest to the inclined side wall is defined as a third end point, a perpendicular line is drawn through the third end point and perpendicular to the inclined side wall, the intersection of the perpendicular line and the inclined side wall is a first intersection point, the horizontal plane where the first intersection point is located is a third plane, the first plane, the second plane and the third plane are parallel to each other, the distance from the first plane to the third plane is h1, the distance from the second plane to the third plane is h2, and h1:h2>0.

8. The h1 is the shortest distance from the first plane to the third plane, and the h2 is the shortest distance from the second plane to the third plane; the first end point is located at the top opening of the V-shaped pit, and the second end point is located at the bottom of the V-shaped pit.

17. The light emitting diode of claim 16, wherein: h1:h2<4.

18. The light emitting diode of claim 16, wherein: h1 is greater than h2.

19. The light emitting diode of claim 16, wherein: The width of the top opening of the V-shaped pit is defined as W1, and the depth of the V-shaped pit is defined as H3, and the ratio of W1 to H3 is in the range of 1-2.

20. A light-emitting device, characterized in that: The light emitting device comprises a circuit board and a light emitting diode, the light emitting diode is arranged on the circuit board, and the light emitting diode adopts the light emitting diode according to any one of claims 1-19.

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