Led, optical communication device, and optical communication system

Abstract

The present application provides an LED, which is applied to the field of LEDs or the field of optical communications. The LED comprises a P-type semiconductor layer, an active layer, and an N-type semiconductor layer. The active layer is located between the P-type semiconductor layer and the N-type semiconductor layer. The active layer comprises M barrier layers and M-1 well layers. The barrier layers and the well layers are alternately distributed. M is an integer greater than 1. Each of the M barrier layers is a P-type doped layer. The sum of the doping concentrations of N first barrier layers among the M barrier layers close to the N-type semiconductor layer is greater than the sum of the doping concentrations of N second barrier layers among the M barrier layers close to the P-type semiconductor layer. When M is an even number, N=M / 2; and when M is an odd number, N=M / 2-1 / 2. According to the technical solution provided in the present application, the bandwidth of the LED can be increased by controlling the P-type doping concentrations of the M barrier layers, thereby improving the optical communication efficiency.

Description

LED, optical communication device, and optical communication system

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on December 26, 2023, with application number 202311818917.8 and application name “LED, optical communication device and optical communication system”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of LEDs or optical communications, and in particular to light emitting diodes (LEDs), LED arrays, optical communication devices, and optical communication systems. Background Art

[0003] Short-distance data communication generally uses electrical interconnection. For example, short-distance interconnection of less than 10 meters in data centers uses copper cables, communication on PCB boards uses metal wires, and metal interconnection between chips also uses metal interconnection. With the rapid development of technologies such as the Internet, cloud computing, edge computing, and artificial intelligence (AI), the communication bandwidth required for short-distance scenarios such as 10-meter interconnection in data centers, interconnection on PCB boards, and interconnection between chips has increased dramatically. Optical interconnection has absolute advantages over electrical interconnection in terms of speed, transmission distance and other performance. Using optical interconnection to replace electrical interconnection has become the mainstream trend in short-distance communication scenarios. In optical interconnection, lasers are generally used as the light source of the transmitter. Lasers have problems such as high threshold current, high power consumption, poor high-temperature operation, and high cost. By using Micro-LED as the light source, it is conducive to realizing low-power, low-cost, wide-temperature operation and high-reliability optical communication systems. However, the bandwidth of Micro-LED is relatively low, which reduces the efficiency of optical communication. Summary of the Invention

[0004] The present application provides an LED, an LED array, an optical communication device, and an optical communication system. By controlling the P-type doping concentration of M barrier layers, the bandwidth of the LED can be increased, thereby improving the efficiency of optical communication.

[0005] In a first aspect, the present application provides an LED. The LED includes a P-type semiconductor layer, an active layer, and an N-type semiconductor layer. The active layer is located between the P-type semiconductor layer and the N-type semiconductor layer. The active layer includes M barrier layers and M-1 well layers. The barrier layers and well layers are alternately distributed. M is an integer greater than 1. Each of the M barrier layers is a P-type doped layer. The sum of the doping concentrations of the N first barrier layers in the M barrier layers, which are adjacent to the N-type semiconductor layer, is greater than the sum of the doping concentrations of the N second barrier layers in the M barrier layers, which are adjacent to the P-type semiconductor layer. When M is an even number, N = M / 2; when M is an odd number, N = M / 2-1 / 2.

[0006] In this application, by doping each barrier layer with P-type, the number of carriers in the active layer can be increased. Furthermore, by controlling the distribution of the P-type doping concentration in the M barrier layers, the uniformity of the carrier distribution in the active region and the transport of carriers in the multi-quantum wells are improved, thereby increasing the bandwidth of the LED.

[0007] In an optional embodiment of the first aspect, the P-type edge barrier layer is the barrier layer closest to the P-type semiconductor layer among the M barrier layers. The N-type edge barrier layer is the barrier layer closest to the N-type semiconductor layer among the M barrier layers. The target barrier layer is a non-edge barrier layer among the M barrier layers. The doping concentration of the barrier layer gradually increases from the N-type edge barrier layer to the target barrier layer. The doping concentration of the barrier layer gradually decreases from the target barrier layer to the P-type edge barrier layer. This doping concentration distribution design is conducive to improving the uniformity of carrier distribution in the active region, thereby improving the concentration matching of electrons and holes and improving the LED bandwidth.

[0008] In an optional manner of the first aspect, M is equal to 6, and in the direction from the N-type semiconductor layer to the P-type semiconductor layer, the doping concentrations of the M barrier layers are C1, C2, C3, C4, C5 and C6, respectively, and C1<C2>C3>C4>C5>C6.

[0009] In an optional embodiment of the first aspect, the doping concentration of the M barrier layers gradually decreases from the N-type semiconductor layer to the P-type semiconductor layer. This doping concentration distribution design can replenish the hole concentration in the quantum well near the N side, thereby improving the LED bandwidth.

[0010] In an optional manner of the first aspect, M is equal to 6, and in the direction from the N-type semiconductor layer to the P-type semiconductor layer, the doping concentrations of the M barrier layers are C1, C2, C3, C4, C5 and C6, respectively, and C1>C2>C3>C4>C5>C6.

[0011] In an optional embodiment of the first aspect, X of the M barrier layers, which are adjacent to the N-type semiconductor layer, have the same doping concentration. Y of the M barrier layers, which are adjacent to the P-type semiconductor layer, have the same doping concentration. The doping concentration of each of the X barrier layers is greater than the doping concentration of each of the Y barrier layers. M is equal to the sum of X and Y. This doping concentration distribution design can reduce the difficulty of LED epitaxy while increasing the LED bandwidth.

[0012] In an optional manner of the first aspect, M is equal to 6, and in the direction from the N-type semiconductor layer to the P-type semiconductor layer, the doping concentrations of the M barrier layers are C1, C2, C3, C4, C5 and C6, respectively, and C1=C2=C3>C4=C5=C6.

[0013] In an optional manner of the first aspect, the doping concentrations of X barrier layers among the M barrier layers, which are close to the N-type semiconductor layer, are the same. The doping concentrations of Y barrier layers among the M barrier layers, which are close to the P-type semiconductor layer, are the same. The doping concentrations of Z barrier layers among the M barrier layers, excluding X barrier layers and Y barrier layers, are the same. The doping concentrations of Z barrier layers among the M barrier layers are the same. The doping concentration of the barrier layers among the X barrier layers is greater than the doping concentration of the barrier layers among the Z barrier layers. The doping concentration of the barrier layers among the Z barrier layers is greater than the doping concentration of the barrier layers among the Y barrier layers. M is equal to the sum of X, Y, and Z. This doping concentration distribution design can reduce the difficulty of controlling the epitaxy of LEDs.

[0014] In an optional manner of the first aspect, M is equal to 6, and in the direction from the N-type semiconductor layer to the P-type semiconductor layer, the doping concentrations of the M barrier layers are C1, C2, C3, C4, C5 and C6, respectively, and C1=C2>C3=C4>C5=C6.

[0015] In an optional manner of the first aspect, the highest doping concentration in the M barrier layers is in the range of 1×10 18 to 1×10 21 The lowest doping concentration in the M barrier layers is in the range of 1×10 16 to 1×10 18 Between each cubic centimeter.

[0016] In one optional embodiment of the first aspect, the sum of the thicknesses of the K first barrier layers and K first well layers proximal to the N-type semiconductor among the M barrier layers and M-1 well layers is greater than the sum of the thicknesses of the K second barrier layers and K second well layers proximal to the P-type semiconductor. When M is an even number, K = M / 2-1. When M is an odd number, K = M / 2-1 / 2. The thicknesses of the barrier layers and well layers proximal to the P side are thinner than those proximal to the N side, which helps increase the carrier density in the quantum wells proximal to the P side and also helps improve carrier transport characteristics in the multi-quantum wells, particularly the injection and transport of hole carriers, thereby improving the bandwidth of the LED.

[0017] In an optional manner of the first aspect, the M-1 well layers have the same thickness, and the M barrier layers have different thicknesses.

[0018] In an optional manner of the first aspect, the K first barrier layers have the same thickness, the K second barrier layers have the same thickness, and the thickness of the first barrier layer is greater than that of the second barrier layer.

[0019] In an optional manner of the first aspect, the M barrier layers include X first barrier layers and Y second barrier layers, M is equal to the sum of X and Y, the X first barrier layers have the same thickness, the Y second barrier layers have the same thickness, and the thickness of the first barrier layer is greater than that of the second barrier layer.

[0020] In an optional manner of the first aspect, the M barrier layers have the same thickness, and the M-1 well layers have different thicknesses.

[0021] In an optional manner of the first aspect, the K first well layers have the same thickness, the K second well layers have the same thickness, and the thickness of the first well layer is greater than that of the second well layer.

[0022] In an optional manner of the first aspect, the M-1 well layers include X-1 first well layers and Y second well layers, the M is equal to the sum of the X and the Y, the thicknesses of the X-1 first well layers are the same, the thicknesses of the Y second well layers are the same, and the thickness of the first well layer is greater than the thickness of the second well layer.

[0023] In an optional manner of the first aspect, the M barrier layers have different thicknesses, and the M-1 well layers have different thicknesses.

[0024] In an optional manner of the first aspect, the M barrier layers include X first barrier layers and Y second barrier layers, M is equal to the sum of X and Y, the X first barrier layers have the same thickness, the Y second barrier layers have the same thickness, and the thickness of the first barrier layer is greater than that of the second barrier layer.

[0025] In an optional manner of the first aspect, the M-1 well layers include X-1 first well layers and Y second well layers, the M is equal to the sum of the X and the Y, the thicknesses of the X-1 first well layers are the same, the thicknesses of the Y second well layers are the same, and the thickness of the first well layer is greater than the thickness of the second well layer.

[0026] A second aspect of the present application provides an LED array, which includes another LED and the LED according to the first aspect or any one of the first aspects, wherein the other LED and the LED share a same substrate.

[0027] A third aspect of the present application provides an optical communication device. The optical communication device includes the LED described in the first aspect or any one of the first aspects, or the LED array described in the second aspect. The optical communication device also includes a processing circuit. The processing circuit is configured to transmit an electrical signal to the LED or LED array. The LED or LED array is configured to generate an optical signal based on the electrical signal.

[0028] In an optional manner of the third aspect, the optical communication device further includes an optical coupling structure, and the optical coupling structure is used to reduce the divergence angle of the LED or the LED in the LED array.

[0029] In an optional manner of the third aspect, the optical communication device further includes a detector (PD), wherein the PD or PD array is configured to receive another optical signal and convert the another optical signal into another electrical signal, and the processing circuit is configured to receive the another electrical signal.

[0030] In an optional manner of the third aspect, the optical communication device further includes another optical coupling structure, the other optical coupling structure being used to focus the other optical signal. The PD or PD array is used to convert the focused other optical signal into another electrical signal.

[0031] A fourth aspect of the present application provides an optical communication system. The optical communication system includes another optical communication device and the optical communication device described in the third aspect or any one of the third aspects. The optical communication device and the other optical communication device are connected via an optical fiber or an optical waveguide. The optical communication device is configured to transmit an optical signal to the other optical communication device. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1a is a first structural schematic diagram of an LED provided in an embodiment of the present application;

[0033] FIG1b is a second structural diagram of an LED provided in an embodiment of the present application;

[0034] FIG2 is a diagram showing the relationship between LED bandwidth and injection current density at different P-type doping concentrations, calculated according to the LED bandwidth formula;

[0035] FIG3 a is a diagram showing the concentration distribution of electrons in the multi-quantum well active region;

[0036] FIG3 b is a diagram showing the concentration distribution of hole carriers in the multi-quantum well active region;

[0037] FIG4 is a third structural diagram of an LED provided in an embodiment of the present application;

[0038] FIG5 is a schematic diagram of a simulation of the bandwidth of an LED with an undoped active barrier layer according to an embodiment of the present application;

[0039] FIG6 is a schematic diagram of a simulation of the bandwidth of an LED using the first exemplary doping method provided in an embodiment of the present application;

[0040] FIG7 is a schematic diagram of a simulation of the bandwidth of an LED using the second exemplary doping method provided in an embodiment of the present application;

[0041] FIG8 is a schematic diagram of a simulation of the bandwidth of an LED using the third exemplary doping method provided in an embodiment of the present application;

[0042] FIG9 a is a fourth structural diagram of an LED provided in an embodiment of the present application;

[0043] FIG9 b is a schematic diagram of the fifth structure of the LED provided in an embodiment of the present application;

[0044] FIG9 c is a sixth structural diagram of an LED provided in an embodiment of the present application;

[0045] FIG9 d is a seventh structural diagram of an LED provided in an embodiment of the present application;

[0046] FIG9e is a schematic diagram of the eighth structure of the LED provided in an embodiment of the present application;

[0047] FIG9f is a ninth structural diagram of an LED provided in an embodiment of the present application;

[0048] FIG9g is a schematic diagram of the tenth structure of the LED provided in an embodiment of the present application;

[0049] FIG10 is a schematic diagram of the structure of an epitaxial wafer provided in an embodiment of the present application;

[0050] FIG11 is an eleventh structural diagram of an LED provided in an embodiment of the present application;

[0051] FIG12 is a schematic diagram of the structure of an LED array provided in an embodiment of the present application;

[0052] FIG13 is a first structural diagram of an optical communication device provided in an embodiment of the present application;

[0053] FIG14 is a second structural diagram of an optical communication device provided in an embodiment of the present application;

[0054] FIG15 is a third structural diagram of the optical communication device provided in an embodiment of the present application;

[0055] FIG16 is a fourth structural diagram of an optical communication device provided in an embodiment of the present application;

[0056] FIG17 is a fifth structural diagram of an optical communication device provided in an embodiment of the present application;

[0057] FIG18 is a schematic diagram of the structure of the optical communication system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0058] The present application provides an LED, an LED array, an optical communication device, and an optical communication system. By controlling the P-type doping concentration of the M barrier layers, the bandwidth of the LED can be increased, thereby improving the efficiency of optical communication. It should be understood that the terms "first," "second," or "target" used in this application are only used for the purpose of distinguishing descriptions and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying an order. In addition, for the sake of simplicity and clarity, reference numbers and / or letters are repeated in multiple figures of this application. Repetition does not indicate a strict limit relationship between the various embodiments and / or configurations.

[0059] The LED provided in this application is applied to the field of LED and / or the field of optical communication. In the field of optical communication, short-distance data communication generally adopts electrical interconnection. Optical interconnection has absolute advantages over electrical interconnection in terms of performance such as speed and transmission distance. The use of optical interconnection to replace electrical interconnection has become the mainstream trend in short-distance communication scenarios. In optical interconnection, lasers are generally used as the light source of the transmitter. Lasers have problems such as high threshold current, high power consumption, poor high-temperature operation, and high cost. By adopting Micro-LED as the light source, it is conducive to the realization of low-power, low-cost, wide-temperature operation and high-reliability optical communication systems. However, the bandwidth of Micro-LED is relatively low, which reduces the efficiency of optical communication.

[0060] To this end, the present application provides an LED. Figure 1a is a first schematic structural diagram of an LED provided in an embodiment of the present application. As shown in Figure 1a, the LED includes a P-type semiconductor layer 101, an active layer 102, and an N-type semiconductor layer 103. The P-type semiconductor layer 101 is also referred to as the P-type layer 101. The N-type semiconductor layer 103 is also referred to as the N-type layer 103. The active layer 102 is located between the P-type semiconductor layer 101 and the N-type semiconductor layer 103. The active layer 102 includes M barrier layers and M-1 well layers. The barrier layers and well layers are arranged alternately. M is an integer greater than 1. In the example of Figure 1a, the active layer 102 includes three barrier layers and two well layers. Each of the M barrier layers is a P-type doped layer. The dopant in the P-type doped layer can be magnesium (Mg). The sum of the doping concentrations of the N first barrier layers, located near the N-type semiconductor layer 103, among the M barrier layers is greater than the sum of the doping concentrations of the N second barrier layers, located near the P-type semiconductor layer 101, among the M barrier layers. When M is an even number, N = M / 2; when M is an odd number, N = M / 2 - 1 / 2. Figure 1b is a second schematic diagram of the structure of the LED provided in an embodiment of the present application. As shown in Figure 1b, when M is 6, the M barrier layers include 3 first barrier layers and 3 second barrier layers.

[0061] According to the ABC model of LED compounding, the internal quantum efficiency of LED can be expressed as:

[0062] Where IQE is the internal quantum efficiency of the LED, A is the defect-related Shockley-Read-Hall (SRH) recombination coefficient, B is the radiative recombination coefficient, C is the Auger recombination coefficient, and n is the carrier density. The differential carrier lifetime τ of the LED is:

[0063] The bandwidth f of the LED 3dB Inversely proportional to the carrier lifetime: τ -1 =2πf 3dB =A+2Bn+3Cn 2

[0064] As can be seen from the above formula, increasing the SRH recombination coefficient A, the radiation recombination coefficient B, the Auger recombination coefficient C and the carrier density n can all increase the bandwidth of the LED. Moreover, as the injection current density n increases, the bandwidth of the LED will also increase. When operating at low current, the current density n in the active region of the LED is very low, resulting in limited bandwidth of the LED at low current. In order to improve the bandwidth of LEDs operating at low currents, doping can be performed in the active region of the LED to provide background carriers and increase the n value. For gallium nitride (GaN)-based LEDs, due to the difficulty of P-type doping and the high P-type activation energy, the hole concentration in the device is much lower than the electron concentration. Therefore, P-type doping can be preferred for doping in the quantum well. Figure 2 is a schematic diagram of the relationship between the bandwidth of the LED and the injection current density at different barrier layer P-type doping concentrations, calculated according to the LED bandwidth formula. The horizontal axis of Figure 2 is the current density, with units of amperes per square centimeter (A / cm2). 2 The vertical axis of Figure 2 is the bandwidth, in gigahertz (GHz). When the quantum well barrier layer is not doped, the relationship between the bandwidth of the LED and the injection current density is shown in curve 201. When the P-type doping concentration of the quantum well barrier layer is 1×10 18 The relationship between the bandwidth of the LED and the injection current density is shown in curve 202. When the P-type doping concentration of the quantum well barrier layer is 5×10 19 The relationship between the bandwidth of the LED and the injection current density is shown in curve 203. When the P-type doping concentration of the quantum well barrier layer is 1×10 20 The relationship between the bandwidth of the LED and the injection current density is shown in curve 204. As shown in FIG2, by doping the quantum well barrier layer with P-type, the bandwidth of the LED can be effectively improved, especially at low current. When the P-type doping concentration reaches 10 19 At low current density, the bandwidth of the LED is significantly improved to 1 GHz. At high current density, the bandwidth of the LED can reach 3 GHz.

[0065] On the other hand, GaN-based LEDs have problems with carrier mismatch and uneven carrier distribution. Figure 3a shows the concentration distribution of electrons in the multi-quantum well active region. Figure 3b shows the concentration distribution of hole carriers in the multi-quantum well active region. The horizontal axis in Figures 3a and 3b represents the distance from the N-type layer 103. The vertical axis in Figures 3a and 3b represents the logarithmic values ​​of the electron concentration and the hole concentration. The unit is Log (electron concentration / cm 3 ) and Log(hole concentration / cm 3 As shown in Figure 3a and Figure 3b, at 500A / cm 2Under low current injection, since the P-type doping efficiency of GaN is much lower than that of N-type doping, and the mobility of holes is lower than that of electrons, the hole concentration injected into the quantum well (15th to 18th power) is one to two orders of magnitude lower than the electron concentration (17.5th to 18.5th power). As shown in Figures 3a and 3b, the distribution of electrons in the multi-quantum wells is more uniform. Compared with the distribution of electrons, the distribution of holes in the multi-quantum wells is more uneven, and the distribution of holes has obvious characteristics of low N-side quantum well concentration and high P-side quantum well concentration. Therefore, in the embodiment of the present application, the P-type doping concentration in the area close to the N side is higher than the P-type doping concentration in the area close to the P side. By controlling the distribution of the P-type doping concentration, the hole concentration close to the N-side quantum well can be supplemented to achieve a more uniform carrier distribution and a more matched electron and hole concentration to increase the bandwidth of the LED.

[0066] According to the description of FIG. 1a above, the sum of the doping concentrations of the N first barrier layers near the N-type semiconductor layer 103 among the M barrier layers is greater than the sum of the doping concentrations of the N second barrier layers near the P-type semiconductor layer 101 among the M barrier layers. The following description takes M equal to 6 as an example. FIG4 is a third structural schematic diagram of the LED provided in an embodiment of the present application. As shown in FIG4 , the LED includes an N-type layer 103, a P-type layer 101, and an active layer located between the N-type layer 103 and the P-type layer 101. The active layer includes six barrier layers. The doping concentrations of the six barrier layers are C1, C2, C3, C4, C5, and C6, respectively. C1+C2+C3>C4+C5+C6. The present application provides several different doping concentration distribution designs. The following description takes M equal to 6 as an example.

[0067] In the first example, the P-type edge barrier layer is the barrier layer closest to the P-type semiconductor layer among the M barrier layers. The N-type edge barrier layer is the barrier layer closest to the N-type semiconductor layer among the M barrier layers. The target barrier layer is a non-edge barrier layer among the M barrier layers. The doping concentration of the barrier layers from the N-type edge barrier layer to the target barrier layer gradually increases. The doping concentration of the barrier layers from the target barrier layer to the P-type edge barrier layer gradually decreases. For example, when the value of C3 is the largest among the doping concentrations of the M barrier layers, C1<C2<C3>C4>C5>C6. When the value of C2 is the largest among the doping concentrations of the M barrier layers, C1<C2>C3>C4>C5>C6. For example, the doping concentration range of C1 is 4.5×10 19 to 5.5×10 19 per cubic centimeter; the doping concentration of C2 ranges from 0.5×10 20 to 1.5×10 20 per cubic centimeter; the doping concentration of C3 ranges from 4.5×10 19 to 5.5×10 19per cubic centimeter; the doping concentration of C4 ranges from 0.5×10 19 to 1.5×10 19 per cubic centimeter; the doping concentration of C5 ranges from 4.5×10 18 to 5.5×10 18 per cubic centimeter; the doping concentration of C6 ranges from 0.5×10 18 to 1.5×10 18 Between each cubic centimeter.

[0068] FIG5 is a schematic diagram of the bandwidth simulation of the LED with non-doped active barrier layer provided by the embodiment of the present application. The horizontal axis of FIG5 is the bandwidth, in GHz. The vertical axis of FIG5 is the responsivity, in decibels (dB). As shown in FIG5, at 500A / cm 2 At a low current density of 500A / cm, the 3dB modulation bandwidth of the LED with non-doped barrier layer is only 0.84GHz. Figure 6 is a simulation diagram of the bandwidth of the LED using the first example of doping provided in the embodiment of the present application. As shown in Figure 6, at 500A / cm 2 At a low current density of 1.5 GHz, the 3 dB modulation bandwidth of the LED using the first example doping method is 1.51 GHz, which is 0.67 GHz higher than the modulation bandwidth of the LED in Figure 5.

[0069] In the second example, the doping concentrations of the M barrier layers gradually decrease along the direction from the N-type semiconductor layer 103 to the P-type semiconductor layer 101. In this case, C1>C2>C3>C4>C5>C6. For example, the doping concentration range of C1 is 4.5×10 20 to 5.5×10 20 per cubic centimeter; the doping concentration of C2 ranges from 0.5×10 20 to 1.5×10 20 per cubic centimeter; the doping concentration of C3 ranges from 4.5×10 19 to 5.5×10 19 per cubic centimeter; the doping concentration of C4 ranges from 0.5×10 19 to 1.5×10 19 per cubic centimeter; the doping concentration of C5 ranges from 4.5×10 18 to 5.5×10 18 per cubic centimeter; the doping concentration of C6 ranges from 0.5×10 18 to 1.5×10 18 Between each cubic centimeter.

[0070] FIG7 is a schematic diagram of the bandwidth simulation of the LED using the second example doping provided in the embodiment of the present application. As shown in FIG7, at 500A / cm 2At a low current density of 1.5 GHz, the 3 dB modulation bandwidth of the LED using the second example doping method is 1.34 GHz, which is 0.5 GHz higher than the modulation bandwidth of the LED in Figure 5.

[0071] In the third example, the doping concentrations of the X barrier layers near the N-type semiconductor layer 103 among the M barrier layers are the same. The doping concentrations of the Y barrier layers near the P-type semiconductor layer 101 among the M barrier layers are the same. The doping concentration of the barrier layers among the X barrier layers is greater than the doping concentration of the barrier layers among the Y barrier layers. M is equal to the sum of X and Y. For example, C1 = C2 = C3 > C4 = C5 = C6. The doping concentrations of C1, C2, and C3 are in the range of 4.5×10 19 to 5.5×10 19 per cubic centimeter; the doping concentration of C4, C5 and C6 ranges from 0.5×10 18 to 1.5×10 18 Between each cubic centimeter.

[0072] FIG8 is a schematic diagram of the bandwidth simulation of the LED using the third example doping method provided in the embodiment of the present application. As shown in FIG8, at 500A / cm 2 At a low current density of 1.5 GHz, the 3 dB modulation bandwidth of the LED using the third example doping method is 1.46 GHz, which is 0.62 GHz higher than the modulation bandwidth of the LED in Figure 5.

[0073] In the fourth example, the doping concentrations of the X barrier layers in the M barrier layers that are close to the N-type semiconductor layer 103 are the same. The doping concentrations of the Y barrier layers in the M barrier layers that are close to the P-type semiconductor layer 101 are the same. The doping concentrations of the other Z barrier layers in the M barrier layers are the same. The doping concentration of the barrier layers in the X barrier layers is greater than the doping concentration of the barrier layers in the Z barrier layers. The doping concentration of the barrier layers in the Z barrier layers is greater than the doping concentration of the barrier layers in the Y barrier layers. M is equal to the sum of X, Y, and Z. For example, C1=C2>C3=C4>C5=C6. The doping concentrations of C1 and C2 are in the range of 4.5×10 19 to 5.5×10 19 per cubic centimeter; the doping concentration of C3 and C4 ranges from 0.5×10 19 to 1.5×10 19 per cubic centimeter; the doping concentration of C5 and C6 ranges from 4.5×10 18 to 5.5×10 18 Between each cubic centimeter.

[0074] According to the description of FIG2 above, it can be seen that the bandwidth of the LED can be increased by P-type doping the barrier layer in the active region. In practical applications, there is an optimal range for the maximum and minimum values ​​of the doping concentration. The optimal range for the highest doping concentration in the M barrier layers is 1×10 18 to 1×1020 The optimal range of the lowest doping concentration in the M barrier layers is 1×10 16 to 1×10 18 Between each cubic centimeter.

[0075] In practical applications, the thickness of the well and barrier layers in the active layer also affects the density, transport, and matching of carriers, thereby affecting the bandwidth of the LED. The LED active layer includes M barrier layers and M-1 well layers. The sum of the thicknesses of the K first well layers and K first barrier layers near the N-type semiconductor layer 103 among all the barrier and well layers is greater than the sum of the thicknesses of the K second barrier layers and K second well layers near the P-type semiconductor layer 101. When M is an even number, K = M / 2-1; when M is an odd number, K = M / 2-1 / 2. Figure 9a is a fourth structural schematic diagram of the LED provided in an embodiment of the present application. This embodiment of the present application is described using M = 6 as an example. As shown in Figure 9a, the LED includes an N-type layer 103, a P-type layer 101, and an active layer located between the N-type layer 103 and the P-type layer 101. The active layer includes 6 barrier layers and 5 well layers. The thicknesses of the six barrier layers are d1, d2, d3, d4, d5, and d6, respectively. The thicknesses of the five well layers are D1, D2, D3, D4, and D5, respectively. The thickness of the well layer or barrier layer refers to the length of the well layer or barrier layer in the first direction. The first direction refers to the light emitting direction of the LED or the reverse direction of light emitting. In the example of Figure 9a, d1+d2+d3+D1+D2>d4+d5+d6+D4+D5. This application provides several different distribution designs of well barrier layer thicknesses. The following describes each of these using M equal to 6 as an example.

[0076] In the first approach, the M-1 well layers have the same thickness, while the M barrier layers have different thicknesses. In this case, D1 = D2 = D3 = D4 = D5. The different thicknesses of the M barrier layers mean that some of the M barrier layers have different thicknesses. For example, d1 > d2 > d3 > d4 > d5 > d6. The M barrier layers can include layers of the same thickness. For example, d1 = d2 > d3 > d4 > d5 > d6. In practical applications, to improve hole injection and transport, the thickness of the barrier layer near the P side can be reduced. The K first barrier layers have the same thickness, and the K second barrier layers have the same thickness, with the thickness of the first barrier layer being greater than that of the second barrier layer. In this case, d1 = d2 = d3 > d4 = d5 = d6. Figure 9b illustrates the fifth structure of an LED provided in an embodiment of the present application. As shown in Figure 9b, D1 = D2 = D3 = D4 = D5, and d1 = d2 = d3 > d4 = d5 = d6. For example, D1 is equal to 2 nanometers. The P-type layer 101 includes a P-ALGaN EBL electron blocking layer 901 and a P-GaN layer 902. It should be understood that in practical applications, the P-type layer 101 may also include a P-AlGaN EBL electron blocking layer 901 and a P-GaN layer 902. +-GaN contact layer. The P-GaN layer 902 is located between the P-ALGaN EBL electron blocking layer 901 and the P + -between GaN contact layers.

[0077] In the second approach, the M barrier layers have the same thickness, while the M-1 well layers have different thicknesses. In this case, d1 = d2 = d3 = d4 = d5 = d6. The different thicknesses of the M-1 well layers refer to the presence of well layers of different thicknesses within the M-1 well layers. For example, D1 > D2 > D3 > D4 > D5. The M-1 well layers can include well layers of the same thickness. For example, D1 = D2 > D3 > D4 > D5. In practical applications, the well layer thickness can be reduced to increase the carrier density in the quantum wells near the P side and to increase the spatial overlap of electron and hole wave functions. The M-1 well layers include X-1 first well layers and Y second well layers. M equals the sum of X and Y. The X-1 first well layers have the same thickness. The Y second well layers have the same thickness. The thickness of the first well layer is greater than that of the second well layer. For example, D1 = D2 > D3 = D4 = D5. Figure 9c illustrates the sixth structure of an LED provided in an embodiment of the present application. As shown in FIG9c, d1 = d2 = d3 = d4 = d5 = d6, D1 = D2 > D3 = D4 = D5. For example, D1 is equal to 3 nanometers and D3 is equal to 1.5 nanometers.

[0078] In the third approach, the M barrier layers have different thicknesses, and the M-1 well layers have different thicknesses. The K first barrier layers have the same thickness. The K second barrier layers have the same thickness. The thickness of the first barrier layer is greater than that of the second barrier layer. The thickness of the first well layer between the K first barrier layers is the same. The thickness of the second well layer between the K second barrier layers is the same. The thickness of the first well layer is greater than that of the second well layer. In this case, d1 = d2 = d3 > d4 = d5 = d6. D1 = D2 > D4 = D5. Figure 9d illustrates the seventh structure of the LED provided in an embodiment of the present application. As shown in Figure 9d, d1 = d2 = d3 > d4 = d5 = d6. D1 = D2 > D3 = D4 = D5. In this design, the barrier layers closer to the P side are thinner, improving hole injection and transport. Simultaneously, the well layers closer to the P side are also thinner, resulting in a higher carrier density in the quantum well and greater spatial overlap of electron and hole wave functions, which helps improve the radiative recombination efficiency and modulation rate of the LED.

[0079] It should be understood that in the embodiments of the present application, the P-type doping concentration of the barrier layer in the LED and the thickness of the active layer well layer and barrier layer can be simultaneously controlled, thereby improving the bandwidth of the LED. For example, Figure 9e is a schematic diagram of the eighth structure of the LED provided in the embodiment of the present application. In the LED of Figure 9e, D1 = D2 = D3 = D4 = D5, d1 = d2 = d3 > d4 = d5 = d6, and C1 < C2 > C3 > C4 > C5 > C6. For another example, Figure 9f is a schematic diagram of the ninth structure of the LED provided in the embodiment of the present application. In the LED of Figure 9f, d1 = d2 = d3 = d4 = d5 = d6, D1 = D2 > D3 = D4 = D5, and C1 < C2 > C3 > C4 > C5 > C6. For another example, Figure 9g is a schematic diagram of the tenth structure of the LED provided in the embodiment of the present application. In the LED of Figure 9g, d1 = d2 = d3 > d4 = d5 = d6. D1=D2>D3=D4=D5, C1<C2>C3>C4>C5>C6. It should be understood that Figures 9e to 9g are just a few examples provided in the embodiments of this application. In actual applications, the doping concentration of the barrier layer can refer to the description of any of the above Figures 4 to 8.

[0080] FIG10 is a schematic diagram of the structure of the epitaxial wafer provided in an embodiment of the present application. As shown in FIG10 , the epitaxial wafer includes a substrate 1002, a non-U-doped GaN layer 1001, an N-type semiconductor layer 103, an active layer 102, and a P-type semiconductor layer 101. The P-type semiconductor layer 101 includes a P-type electron blocking layer, a P-GaN layer, and a P-type semiconductor layer. + -GaN contact layer. The N-type semiconductor layer 103 includes an n-GaN layer and a superlattice layer. By bonding the epitaxial wafer to other chips and removing the substrate 1002 and the U-GaN layer, a flip-chip LED can be manufactured.

[0081] Figure 11 is the eleventh structural schematic diagram of an LED provided in an embodiment of the present application. As shown in Figure 11 , based on Figure 1a , the LED comprises, in order along a first direction, a substrate 1101, a lower electrode layer 1102, a P-type semiconductor layer 101, an active layer 102, an N-type semiconductor layer 103, a transparent upper electrode layer 1103, an upper reflective layer 1104, and a focusing layer 1105. Substrate 1101 can be made of silicon, an integrated circuit chip, a silicon interposer, an organic substrate, a glass substrate, or a sapphire substrate. Substrate 1101 serves as a base and provides processing and control circuitry. Lower electrode layer 1102 is located between substrate 1101 and P-type semiconductor layer 101. Lower electrode layer 1102 can be made of metal. P-type semiconductor layer 101 is located between lower electrode layer 1102 and active layer 102. P-type semiconductor layer 101 can be made of GaN, for example. Active layer 102 is located between P-type semiconductor layer 101 and N-type semiconductor layer 103. The P-type semiconductor layer 101 is used to provide hole carriers, and the N-type semiconductor layer 103 is used to provide electron carriers. The active layer 102 can be a quantum well composed of gallium nitride (GaN) and indium gallium nitride (InGaN). The active layer 102 is used for radiative recombination of hole and electron carriers. The N-type semiconductor layer 103 is located between the active layer 102 and the transparent upper electrode layer 1103. The material of the N-type semiconductor layer 103 can be GaN, etc. The transparent upper electrode layer 1103 is located between the N-type semiconductor layer 103 and the upper reflective layer 1104. The transparent upper electrode layer 1103 can be a transparent conductive film. The material of the transparent upper electrode layer 1103 can be indium tin oxide or aluminum zinc oxide, etc. The transmittance of the transparent upper electrode layer 1103 is greater than 0%. For example, in practical applications, the transmittance of the transparent upper electrode layer 1103 for visible light is greater than 30%, 50%, 70%, or 90%. The upper reflective layer 1104 can be a distributed Bragg reflection (DBR) reflective layer. The material of the upper reflective layer 1104 can be silicon dioxide, titanium dioxide, aluminum oxide, tantalum pentoxide, or a combination thereof. The upper reflective layer 1104 is used to reflect photons. The focusing layer 1105 is also called a spacer layer. The material of the focusing layer 1105 can be insulating adhesive. A lens 1110 is provided on the focusing layer 1105 of the LED. Lens 1110 is used to adjust the divergence angle of the light signal output by the LED, thereby improving the coupling efficiency of the light signal into the optical fiber or waveguide.

[0082] The LED also includes an isolation layer 1107 and a connecting electrode 1109. A first electrode 1106 and a second electrode 1108 are provided on a substrate 1101. The isolation layer 1107 can be made of an insulating adhesive. Other materials for the isolation layer 1107 include silicon dioxide or silicon nitride. The isolation layer 1107 is used to isolate the connecting electrode 1109 from the lower electrode layer 1102, the P-type semiconductor layer 101, the active layer 102, and the N-type semiconductor layer 103. The connecting electrode 1109 is used to connect the transparent upper electrode layer 1103 to the second electrode 1108. The lower electrode layer 1102 is connected to the first electrode 1106. In the example of FIG. 1a , the LED supplies power to the transparent upper electrode layer 1103 via the second electrode 1108 on the substrate 1101, and to the lower electrode layer 1102 via the first electrode 1106 on the substrate 1101.

[0083] It should be understood that Figure 11 is only an example of the LED provided in the embodiment of the present application. In actual applications, those skilled in the art can adaptively modify the structure of the LED as needed. For example, in Figure 11, the positions of the P-type semiconductor layer 101 and the N-type semiconductor layer 103 are interchanged. At this time, the P-type semiconductor layer 101 is located between the active layer 102 and the transparent upper electrode layer 1103, and the N-type semiconductor layer 103 is located between the active layer 102 and the transparent lower electrode layer 1102. For another example, the lower electrode layer 1102 includes a lower reflection layer and a bonding metal layer. The lower reflection layer is located between the bonding metal layer and the P-type semiconductor layer 101. The bonding metal layer is between the substrate 1101 and the lower reflection layer.

[0084] In an embodiment of the present application, the LED can be a micro light emitting diode (Micro-LED) or a resonant cavity micro light emitting diode (RC Micro-LED). For example, the length of the P-type semiconductor layer 101 can be less than 100 microns. The length of the P-type semiconductor layer 101 can also be referred to as the lateral dimension of the P-type semiconductor layer 101 or the table dimension of the LED. When Figure 11 is a side view of the LED, the length of the P-type semiconductor layer 101 refers to the maximum dimension of the P-type semiconductor layer 101 in the top view of the LED. For example, when the shape of the P-type semiconductor layer 101 in the top view is circular, the length of the P-type semiconductor layer 101 refers to the diameter of the P-type semiconductor layer 101.

[0085] The present application also provides an LED array, comprising another LED and the LED described in Figures 1a, 1b, 4, 9a-9g, or 11. The structure of the other LED in the LED array can refer to the LED described in Figures 1a, 1b, 4, 9a-9g, or 11. The other LED and the LED share the same substrate. Figure 12 is a schematic structural diagram of the LED array provided in the present application. As shown in Figure 12, the LED array includes two LEDs, LED 1201 and LED 1202. Based on Figure 11, LED 1201 further includes an insulating layer 1204 and a leveling layer 1205. Leveling layer 1205 is used to fill the area between substrate 1101 and transparent upper electrode layer 1103. Portions of leveling layer 1205 can serve as an isolation layer. The description of LED 1202 can refer to the description of LED 1201. LED 1202 and LED 1201 share substrate 1101. In the example of FIG12 , LED 1202 and LED 1201 also share upper reflective layer 1104 and focusing layer 1105. A lens 1203 is provided above LED 1202. For the description of lens 1203, reference can be made to the description of lens 1110. It should be understood that the number of LEDs in an LED array is not limited to two; depending on application requirements, the number of LEDs can be expanded to dozens, hundreds, thousands, or even more.

[0086] The embodiment of the present application also provides an optical communication device. Figure 13 is a first structural schematic diagram of the optical communication device provided in the embodiment of the present application. As shown in Figure 13, the optical communication device 1300 includes a processing circuit 1301 and an LED 1302. The optical communication device 1300 can also be called an optical transmitting module, an optical transceiver module, an optical module, an optical transmitting device, an optical transmitting end, an optical communication device or an optical interconnected transceiver device, etc. The processing circuit 1301 can also be called a logic circuit. The processing circuit 1301 can be a processor. For example, the processing circuit 1301 can be a central processing unit (CPU), a graphics processing unit (GPU), a neural network processing unit (NPU), a network processor (NP), or a combination of a CPU and an NP. The processing circuit 1301 can further include a hardware chip or other general-purpose processor. The above-mentioned hardware chip can be an application specific integrated circuit (ASIC), a programmable logic device (PLD) or a combination thereof. The processing circuit 1301 is used to transmit electrical signals to the LED 1302. The LED 1302 is used to generate an optical signal according to the electrical signal. For the description of the LED 1302, reference can be made to the description of any of Figures 1a, 1b, 4, 9a to 9g, or 11.

[0087] In practical applications, the optical communication device 1300 may include a processing circuit 1301 and an LED array. For a description of the LED array, refer to the description of FIG. 12 . The processing circuit 1301 is configured to transmit multiple electrical signals to the LED array. The LED array includes multiple LEDs. There is a one-to-one correspondence between the multiple LEDs and the multiple electrical signals. The multiple LEDs are configured to generate multiple optical signals based on the multiple electrical signals. There is a one-to-one correspondence between the multiple optical signals and the multiple LEDs.

[0088] FIG14 is a second schematic diagram of the structure of the optical communication device provided in an embodiment of the present application. As shown in FIG14 , based on FIG13 , the optical communication device 1300 further includes a driving circuit 1401 and a lens 1402. The driving circuit 1401 is configured to receive an electrical signal from the processing circuit 1301 and to obtain a driving electrical signal based on the electrical signal. The driving circuit 1401 is also configured to transmit the driving electrical signal to the LED 1302. The LED 1302 is configured to generate an optical signal based on the driving electrical signal and output the optical signal through the lens 1402. For the positional relationship between the lens 1402 and the LED 1302, reference can be made to the description of FIG11 .

[0089] Figure 15 is a third structural schematic diagram of the optical communication device provided in an embodiment of the present application. As shown in Figure 15, based on Figure 14, the optical communication device 1300 also includes a lens 1501, a PD 1502, an amplifier circuit 1503 and a processing circuit 1504. Lens 1501 is used to receive another optical signal, adjust the divergence angle of the other optical signal, and focus the other optical signal to PD 1502. PD 1502 is used to convert the other optical signal into another electrical signal and transmit the electrical signal to the amplifier circuit 1503. The amplifier circuit 1503 can include a trans-impedance amplifier (TIA) and a limiting amplifier (LA). The amplifier circuit 1503 is used to amplify the other electrical signal and transmit the amplified electrical signal to the processing circuit 1504. The processing circuit 1504 and the processing circuit 1301 can be the same processor. The processing circuit 1504 is used to process the amplified electrical signal. In practical applications, to reduce the cost of optical communication device 1300 or increase its integration, PD 1502 and LED 1302 can be integrated on a single substrate. In this case, PD 1502 and LED 1302 share the same substrate. Lens 1402, LED 1302, driver circuit 1401, lens 1501, PD 1502, and amplifier circuit 1503 can also be integrated on the same substrate. In this case, lens 1402, LED 1302, driver circuit 1401, lens 1501, PD 1502, and amplifier circuit 1503 share the same substrate. Lens 1402, LED 1302, driving circuit 1401, processing circuit 1301 and lens 1501, PD 1502, amplifying circuit 1503, processing circuit 1504 can be integrated on the same substrate. In this case, lens 1402, LED 1302, driving circuit 1401, processing circuit 1301 and lens 1501, PD 1502, amplifying circuit 1503, processing circuit 1504 share the same substrate.

[0090] Figure 16 is a fourth structural schematic diagram of an optical communication device provided in an embodiment of the present application. As shown in Figure 16, optical communication device 1600 includes a processing circuit 1601, multiple driving circuits 1602, an LED array 1603, and a lens array 1604. For the description of processing circuit 1601, reference can be made to the description of processing circuit 1301 in Figure 13 . Processing circuit 1601 is used to generate multiple electrical signals. Multiple driving circuits 1602 are used to generate multiple driving electrical signals based on the multiple electrical signals. The multiple driving circuits 1602 correspond one-to-one with the multiple driving electrical signals. The multiple driving electrical signals correspond one-to-one with the multiple electrical signals. LED array 1603 includes multiple LEDs. The multiple LEDs are used to generate multiple optical signals based on the multiple driving electrical signals. The multiple LEDs correspond one-to-one with the multiple optical signals. The multiple driving electrical signals correspond one-to-one with the multiple optical signals. Lens array 1604 includes multiple lenses. The multiple lenses are used to adjust the divergence angles of the multiple optical signals. The multiple lenses correspond one-to-one with the multiple optical signals.

[0091] FIG17 is a fifth structural schematic diagram of an optical communication device provided in an embodiment of the present application. As shown in FIG17 , based on FIG16 , optical communication device 1600 further includes a lens array 1701, a PD array 1702, an amplifier array 1703, and a processing circuit 1704. Lens array 1701 includes multiple lenses. The multiple lenses are used to receive multiple optical signals and focus the multiple optical signals onto multiple PDs in PD array 1702. The multiple optical signals correspond one-to-one to the multiple lenses. The multiple optical signals correspond one-to-one to the multiple PDs. The multiple PDs convert the multiple optical signals into multiple electrical signals and transmit the multiple electrical signals to the multiple amplifier circuits in amplifier array 1703. The multiple electrical signals correspond one-to-one to the multiple PDs, and the multiple electrical signals correspond one-to-one to the multiple amplifier circuits. The multiple amplifier circuits are used to amplify the multiple electrical signals to obtain multiple amplified electrical signals, which are then transmitted to processing circuit 1704. The multiple amplified electrical signals correspond one-to-one to the multiple electrical signals. Processing circuit 1704 and processing circuit 1601 can be the same processor.

[0092] Figure 18 is a schematic diagram of the structure of the optical communication system provided in an embodiment of the present application. As shown in Figure 18, the optical communication system 1800 includes an optical communication device 1801 and another optical communication device 1802. The optical communication device 1801 and the another optical communication device 1802 are connected through an optical fiber or a waveguide. The optical fiber can be a single-mode optical fiber, a multi-mode optical fiber, an imaging optical fiber, a multi-core optical fiber, a light-guiding optical fiber or a plastic optical fiber, etc. The waveguide can be a flexible optical waveguide or a dielectric optical waveguide, etc. The optical communication device 1801 is used to transmit one or more optical signals to another optical communication device 1802. For the description of the optical communication device 1801, reference can be made to the aforementioned description of the optical communication device in any of Figures 13 to 17. When the optical communication device 1801 is the optical communication device in Figure 13, Figure 14 or Figure 15, the optical communication device 1801 is used to transmit an optical signal to another optical communication device 1802. 16 or 17 , the optical communication device 1801 is used to transmit multiple optical signals to another optical communication device 1802. For the description of the other optical communication device 1802, reference can be made to the description of the optical communication device 1801.

[0093] The above is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be covered by the protection scope of the present application.

Claims

1. A light emitting diode (LED), characterized in that, It includes a P-type semiconductor layer, an active layer, and an N-type semiconductor layer, where: The active layer is located between the P-type semiconductor layer and the N-type semiconductor layer. The active layer includes M barrier layers and M - 1 well layers, which are alternately distributed. M is an integer greater than 1. Each of the M barrier layers is a P-type doped layer. The sum of the doping concentrations of the N first barrier layers among the M barrier layers close to the N-type semiconductor layer is greater than the sum of the doping concentrations of the N second barrier layers among the M barrier layers close to the P-type semiconductor layer. When M is an even number, N = M / 2; when M is an odd number, N = M / 2 - 1 / 2.

2. The LED according to claim 1, wherein The P-type edge barrier layer is the barrier layer closest to the P-type semiconductor layer among the M barrier layers. The N-type edge barrier layer is the barrier layer closest to the N-type semiconductor layer among the M barrier layers. The target barrier layer is a non-edge barrier layer among the M barrier layers. The doping concentration of the barrier layers from the N-type edge barrier layer to the target barrier layer gradually increases, and the doping concentration of the barrier layers from the target barrier layer to the P-type edge barrier layer gradually decreases.

3. The LED according to claim 2, characterized in that, M is equal to 6. In the direction from the N-type semiconductor layer to the P-type semiconductor layer, the doping concentrations of the M barrier layers are C1, C2, C3, C4, C5, and C6 respectively, and C1 < C2 > C3 > C4 > C5 > C6.

4. The LED according to claim 1, characterized in that, In the direction from the N-type semiconductor layer to the P-type semiconductor layer, the doping concentrations of the M barrier layers gradually decrease.

5. The LED according to claim 4, wherein M is equal to 6. In the direction from the N-type semiconductor layer to the P-type semiconductor layer, the doping concentrations of the M barrier layers are C1, C2, C3, C4, C5, and C6 respectively, and C1 > C2 > C3 > C4 > C5 > C6.

6. The LED according to claim 1, wherein The doping concentrations of the X barrier layers among the M barrier layers close to the N-type semiconductor layer are the same. The doping concentrations of the Y barrier layers among the M barrier layers close to the P-type semiconductor layer are the same. The doping concentration of the barrier layers of the X barrier layers is different from that of the barrier layers of the Y barrier layers. M is equal to the sum of X and Y.

7. The LED according to claim 6, wherein M is equal to 6. In the direction from the N-type semiconductor layer to the P-type semiconductor layer, the doping concentrations of the M barrier layers are C1, C2, C3, C4, C5, and C6 respectively, and C1 = C2 = C3 > C4 = C5 = C6.

8. The LED according to claim 1, wherein The doping concentrations of the X barrier layers among the M barrier layers close to the N-type semiconductor layer are the same. The doping concentrations of the Y barrier layers among the M barrier layers close to the P-type semiconductor layer are the same. Among the M barrier layers, excluding the X barrier layers and the Y barrier layers, the doping concentrations of the Z barrier layers are the same. The doping concentration of the barrier layers of the X barrier layers is greater than that of the barrier layers of the Z barrier layers. The doping concentration of the barrier layers of the Z barrier layers is greater than that of the barrier layers of the Y barrier layers. M is equal to the sum of X, Y, and Z.

9. The LED according to claim 8, wherein, M is equal to 6. In the direction from the N-type semiconductor layer to the P-type semiconductor layer, the doping concentrations of the M barrier layers are C1, C2, C3, C4, C5, and C6 respectively, and C1 = C2 > C3 = C4 > C5 = C6.

10. The LED according to any one of claims 1 to 9, characterized in that, The doping concentration range of the highest doping concentration among the M barrier layers is between 1×10 18 and 1×10 21 per cubic centimeter, and the doping concentration range of the lowest doping concentration among the M barrier layers is between 1×10 16 and 1×10 18 per cubic centimeter.

11. The LED according to any one of claims 1 to 10, characterized in that, The sum of the thicknesses of the K first barrier layers and the K first well layers among the M barrier layers and the M - 1 well layers, which are close to the N-type semiconductor, is greater than the sum of the thicknesses of the K second barrier layers and the K second well layers, which are close to the P-type semiconductor. When M is an even number, K = M / 2 - 1; when M is an odd number, K = M / 2 - 1 / 2.

12. The LED according to claim 11, wherein, The thicknesses of the M - 1 well layers are the same, and the thicknesses of the M barrier layers are different.

13. The LED according to claim 12, wherein The thicknesses of the K first barrier layers are the same, the thicknesses of the K second barrier layers are the same, and the thickness of the first barrier layer is greater than that of the second barrier layer.

14. The LED according to claim 12, characterized in that, The M barrier layers include X first barrier layers and Y second barrier layers. M is equal to the sum of X and Y. The thicknesses of the X first barrier layers are the same, the thicknesses of the Y second barrier layers are the same, and the thickness of the first barrier layer is greater than that of the second barrier layer.

15. The LED according to claim 11, wherein The thicknesses of the M barrier layers are the same, and the thicknesses of the M - 1 well layers are different.

16. The LED according to claim 15, characterized in that, The thicknesses of the K first well layers are the same, the thicknesses of the K second well layers are the same, and the thickness of the first well layer is greater than that of the second well layer.

17. The LED according to claim 15, wherein, The M - 1 well layers include X - 1 first well layers and Y second well layers. M is equal to the sum of X and Y. The thicknesses of the X - 1 first well layers are the same, the thicknesses of the Y second well layers are the same, and the thickness of the first well layer is greater than that of the second well layer.

18. The LED according to claim 11, wherein, The thicknesses of the M barrier layers are different, and the thicknesses of the M - 1 well layers are different.

19. The LED according to claim 18, wherein The M barrier layers include X first barrier layers and Y second barrier layers. M is equal to the sum of X and Y. The thicknesses of the X first barrier layers are the same, the thicknesses of the Y second barrier layers are the same, and the thickness of the first barrier layer is greater than that of the second barrier layer.

20. The LED according to claim 18, wherein, The M - 1 well layers include X - 1 first well layers and Y second well layers. M is equal to the sum of X and Y. The thicknesses of the X - 1 first well layers are the same, the thicknesses of the Y second well layers are the same, and the thickness of the first well layer is greater than that of the second well layer.

21. A light-emitting diode (LED) array, characterized in that, Comprising another LED and the LED according to any one of the preceding claims 1 to 20, and the other LED and the LED share the same substrate.

22. An optical communication device, characterized in that, Comprising the light-emitting diode LED according to any one of the preceding claims 1 to 20 or the LED array according to claim 21 above, the optical communication device further comprises a processing circuit, wherein: The processing circuit is configured to transmit an electrical signal to the LED or the LED array; The LED or the LED array is configured to generate an optical signal according to the electrical signal.

23. The optical communication device according to claim 22, wherein, The optical communication device further comprises an optical coupling structure, wherein: The optical coupling structure is configured to reduce the emission angle of the LEDs in the LED or the LED array.

24. The optical communication device according to claim 22 or 23, characterized in that, The optical communication device further comprises a detector PD or a PD array, wherein: The PD or the PD array is configured to receive another optical signal and convert the another optical signal into another electrical signal; The processing circuit is configured to receive the another electrical signal.

25. The optical communication device according to claim 24, characterized in that, The optical communication device further comprises another optical coupling structure, wherein: The another optical coupling structure is configured to condense the another optical signal. The PD or the PD array is configured to convert the concentrated another optical signal into another electrical signal.

26. An optical communication system, characterized in that, Comprising another optical communication device and the optical communication device according to any one of the preceding claims 22 to 25, wherein: The optical communication device and the another optical communication device are connected by an optical fiber or an optical waveguide, and the optical communication device is configured to transmit an optical signal to the another optical communication device.

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