A deep ultraviolet LED for regulating the light-emitting angle and a preparation method thereof

Abstract

The present invention discloses a deep ultraviolet LED for regulating the light-emitting angle and a preparation method thereof. The deep ultraviolet LED for regulating the light-emitting angle includes a sapphire substrate, an AlN intrinsic layer, an n-type AlGaN intrinsic layer, a current spreading layer, a light-emitting angle regulating layer, a multi-quantum well active layer, an electron blocking layer, a p-type AlGaN hole injection layer, and a p-type GaN contact layer which are sequentially stacked; the light-emitting angle regulating layer is an AlGaN single-layer structure or an AlGaN multi-layer periodic structure, and the percentage of Al component in the light-emitting angle regulating layer is greater than the percentage of Al component in the quantum barrier of the multi-quantum well active layer. By introducing the light-emitting angle regulating layer between the multi-quantum well active layer and the current spreading layer, the present invention improves the compressive stress on the multi-quantum well active layer, increases the forward light emission amount of the deep ultraviolet LED, improves the light-emitting angle of the deep ultraviolet LED, and thus realizes the improvement of the ultraviolet sterilization efficiency.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor optoelectronics, and particularly to a deep ultraviolet LED for regulating the light-emitting angle and a preparation method thereof. Background Art

[0002] As an outstanding representative of wide-bandgap semiconductor materials, group III nitrides have realized high-efficiency solid-state light source devices such as blue and green light-emitting diodes (full name: light-emitting diodes, abbreviated as LED) and lasers, and have achieved great success in applications such as flat panel displays and white lighting. In recent years, people have expected to apply this high-efficiency light-emitting material to the ultraviolet band to meet the growing demand for ultraviolet light sources. The ultraviolet band can generally be divided into: long-wave ultraviolet (i.e., UVA, wavelength 320-400 nm), medium-wave ultraviolet (i.e., UVB, wavelength 280-320 nm), short-wave ultraviolet (i.e., UVC, wavelength 200-280 nm), and vacuum ultraviolet (i.e., VUV, wavelength 10-200 nm) according to its biological effects. Although ultraviolet light cannot be perceived by the human eye, its applications are very extensive. Long-wave ultraviolet light sources have great application prospects in fields such as medical treatment, ultraviolet curing, ultraviolet lithography, information storage, and plant lighting; while deep ultraviolet light, which includes medium-wave ultraviolet and short-wave ultraviolet, plays an irreplaceable role in sterilization and disinfection, water purification, biochemical detection, non-line-of-sight communication, etc.

[0003] Currently, one of the reasons for the low luminous efficiency of deep ultraviolet LED devices is the low light extraction efficiency. The light extraction efficiency refers to the ratio of the actually emitted light in the LED device to the light emitted from the quantum well active region. The light extraction efficiency is mainly related to three factors: ① absorption of p-type GaN; ② absorption of the p-type electrode; ③ absorption of the n-type electrode. The light emitted from the quantum well active region has two components, TE and TM. Among them, the light in the TE mode propagates parallel to the c direction of crystal growth and can be emitted from the front of the device, while the light in the TM mode, whose propagation direction is perpendicular to the c direction of crystal growth, is laterally emitted and will be reflected multiple times in the device, and finally shows the above three absorption methods ①②③, resulting in a decrease in the light extraction efficiency. Therefore, how to improve the front light output of deep ultraviolet LED devices has become an urgent problem to be solved. Summary of the Invention

[0004] The purpose of the present invention is to provide a deep ultraviolet LED for regulating the light-emitting angle and a preparation method thereof to solve the problem of low light extraction efficiency of existing deep ultraviolet LEDs.

[0005] To solve the above technical problems, the first solution provided by the present invention is: a deep ultraviolet LED for regulating the light-emitting angle, comprising a sapphire substrate, an AlN intrinsic layer, an n-type AlGaN intrinsic layer, a current spreading layer, a light-emitting angle regulating layer, a multi-quantum well active layer, an electron blocking layer, a p-type AlGaN hole injection layer, and a p-type GaN contact layer which are arranged in a stacked manner in sequence; the light-emitting angle regulating layer is an AlGaN single-layer structure or an AlGaN multi-layer periodic structure, and the percentage of Al component in the light-emitting angle regulating layer is greater than the percentage of Al component in the quantum barrier of the multi-quantum well active layer.

[0006] Among them, when the light-emitting angle regulating layer is an Al x Ga 1-x N single-layer structure, the percentage of Al component in the current spreading layer is a, the percentage of Al component in the quantum barrier of the quantum well active region is b, and the percentage of Al component in the quantum barrier of the quantum well active region is c, satisfying x≥a and x≥b + 20%≥c + 5%.

[0007] Preferably, when the light-emitting angle regulating layer is an Al x Ga 1-x N single-layer structure, the thickness of the light-emitting angle regulating layer is 0.1 nm to 500 nm.

[0008] Preferably, when the light-emitting angle regulating layer is an Al x Ga 1-x N single-layer structure, the doping concentration of the light-emitting angle regulating layer is 1×10 12 ~1×10 22 cm -3 .

[0009] Among them, when the light-emitting angle regulating layer is an Al y Ga 1-y N / Al z Ga 1-z N multi-layer periodic structure, the percentage of Al component in the current spreading layer is a, the percentage of Al component in the quantum barrier of the quantum well active region is b, and the percentage of Al component in the quantum barrier of the quantum well active region is c, satisfying y - 5%≥z≥a and y - 5%≥z≥b + 20%≥c + 5%.

[0010] Preferably, when the light-emitting angle regulating layer is an Al y Ga 1-y N / Al z Ga 1-z N multi-layer periodic structure, in the light-emitting angle regulating layer, the thickness of the Al y Ga 1-y N layer is 0.1 nm to 200 nm, and the thickness of the Al z Ga 1-z N layer is 0.1 nm to 100 nm.

[0011] Preferably, the light extraction angle regulation layer is Al y Ga 1-y N / Al z Ga 1-z N multi-layer periodic structure, the doping concentration of the light extraction angle regulation layer is 1×10 12 ~1×10 22 cm -3 。

[0012] To solve the above technical problems, the second solution provided by the present invention is: a preparation method of a deep ultraviolet LED for regulating the light extraction angle, which is used to prepare the deep ultraviolet LED for regulating the light extraction angle in the foregoing first solution, and includes the following steps:

[0013] (1) Under the condition of 400-800°C, grow a buffer layer in the AlN intrinsic layer on the sapphire substrate, with a thickness of 10-50 nm.

[0014] (2) Raise the temperature to 1200-1400°C, and grow an AlN intrinsic layer on the buffer layer in the AlN intrinsic layer. The total thickness of the AlN intrinsic layer is 500-4000 nm.

[0015] (3) Lower the temperature to 800-1200°C, and grow an n-type AlGaN intrinsic layer on the AlN intrinsic layer, where the percentage of Al component is 20-90%, and the thickness is 500-4000 nm.

[0016] (4) Maintain the temperature in step (3), stop introducing SiH4 doping, and grow a current spreading layer on the n-type AlGaN intrinsic layer, where the percentage of Al component is 20-90%, and the thickness is 10-300 nm.

[0017] (5) Raise the temperature to 800-1300°C, and grow a light extraction angle regulation layer on the current spreading layer. The thickness of the light extraction angle regulation layer is 0.1-500 nm.

[0018] (6) Lower the temperature to 700-1100°C, and grow a multi-quantum well active layer on the light extraction angle regulation layer, where the quantum well thickness of the multi-quantum well active layer is 0.1-5 nm and the percentage of Al component in the quantum well is 20-90%, and the quantum barrier thickness is 0.1-20 nm and the percentage of Al component in the barrier is 30-100%.

[0019] (7) Under the condition of 700-1100°C, grow an electron blocking layer on the multi-quantum well active layer, with a thickness of 1-50 nm and the percentage of Al component being 10-100%.

[0020] (8) Under the condition of 700 - 1100 °C, a p-type AlGaN hole injection layer is grown on the electron blocking layer, with the Al component percentage being 10 - 100%, the thickness being 1 - 50 nm, and Mg is used as the p-type dopant.

[0021] (9) Under the condition of 400 - 900 °C, a p-type GaN contact layer is grown on the p-type AlGaN hole injection layer, with the thickness being 1 - 20 nm, and Mg is used as the p-type dopant.

[0022] Among them, the growth temperature of the light extraction angle control layer in step (5) is T0, the growth temperature of the current spreading layer in step (4) is T1, and the growth temperature of the multi-quantum well active layer in step (6) is T2. The three satisfy: T0 ≥ T2 ≥ T1.

[0023] Among them, the ammonia consumption of the light extraction angle control layer in step (5) is N0, the ammonia consumption of the current spreading layer in step (4) is N1, and the ammonia consumption of the multi-quantum well active layer in step (6) is N2. The three satisfy: N0 ≤ N1 ≤ N2.

[0024] The beneficial effects of the present invention are as follows: Different from the prior art, the present invention provides a deep ultraviolet LED for regulating the light extraction angle and its preparation method. By introducing a light extraction angle control layer between the multi-quantum well active layer and the current spreading layer, the compressive stress on the multi-quantum well active layer is increased, the forward light output of the deep ultraviolet LED is increased, the light extraction angle of the deep ultraviolet LED is improved, and thus the ultraviolet sterilization efficiency is improved. Description of the Drawings

[0025] Figure 1 is a schematic structural diagram of an embodiment of the deep ultraviolet LED for regulating the light extraction angle in the present invention;

[0026] Figure 2 is the far-field light emission distribution diagram of the deep ultraviolet LED samples of Comparative Examples 1 and 3 and the deep ultraviolet LED sample of Example 1 in the present invention. Detailed Embodiments

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] For the first solution proposed in the present invention, please refer to Figure 1 , Figure 1It is a schematic structural diagram of an embodiment of a deep ultraviolet LED for adjusting the light-emitting angle in the present invention. The deep ultraviolet LED for adjusting the light-emitting angle in the present invention includes a sapphire substrate 1, an AlN intrinsic layer 2, an n-type AlGaN intrinsic layer 3, a current spreading layer 4, a light-emitting angle adjusting layer 5, a multi-quantum well active layer 6, an electron blocking layer 7, a p-type AlGaN hole injection layer 8, and a p-type GaN contact layer 9 which are arranged in layers in sequence; the light-emitting angle adjusting layer 5 is an AlGaN single-layer structure or an AlGaN multi-layer periodic structure, and the percentage of Al component in the light-emitting angle adjusting layer 5 is greater than the percentage of Al component in the quantum barrier of the multi-quantum well active layer 6.

[0029] Since the light-emitting angle adjusting layer can be designed in two ways: an AlGaN single-layer structure or an AlGaN multi-layer periodic structure, the specific process parameter requirements for the two design methods are as follows:

[0030] a) When the light-emitting angle adjusting layer is an Al x Ga 1-x N single-layer structure, the percentage of Al component in the current spreading layer is a, the percentage of Al component in the quantum barrier of the quantum well active region is b, and the percentage of Al component in the quantum well of the quantum well active region is c, satisfying x≥a and x≥b + 20%≥c + 5%. Among them, the thickness of the light-emitting angle adjusting layer is preferably 0.1 nm to 500 nm, and the doping concentration of the light-emitting angle adjusting layer is preferably 1×10 12 ~1×10 22 cm -3 .

[0031] b) When the light-emitting angle adjusting layer is an Al y Ga 1-y N / Al z Ga 1-z N multi-layer periodic structure, the percentage of Al component in the current spreading layer is a, the percentage of Al component in the quantum barrier of the quantum well active region is b, and the percentage of Al component in the quantum well of the quantum well active region is c, satisfying y - 5%≥z≥a and y - 5%≥z≥b + 20%≥c + 5%. Among them, in the light-emitting angle adjusting layer, the thickness of the Al y Ga 1-y N layer is preferably 0.1 nm to 200 nm, and the thickness of the Al z Ga 1-z N layer is preferably 0.1 nm to 100 nm; the doping concentration of the light-emitting angle adjusting layer is preferably 1×10 12 ~1×10 22 cm -3 .

[0032] In the preparation process of the deep ultraviolet LED for adjusting the light-emitting angle, the MOCVD method is adopted. In addition, an n electrode 10 is arranged on the n-type AlGaN intrinsic layer and a p electrode 11 is arranged on the p-type GaN contact layer by conventional methods to form a complete epitaxial chip structure. The specific process will not be elaborated here.

[0033] Specifically, the principle of the above deep ultraviolet LED for adjusting the light-emitting angle is analyzed. The deep ultraviolet TE / TM mode emitted light is determined by the AlGaN material, which is caused by the different spatial positions of the heavy hole band (HH), light hole band (LH), and crystal field split energy band (CH) at the top of the valence band of GaN and AlN. In the wurtzite structure GaN material, the top of the valence band is the heavy hole band, and the main transition process is that electrons transition from the bottom of the conduction band to the heavy hole band, emitting TE mode photons; in the wurtzite structure AlN material, the top of the valence band is the crystal field split energy band, and the main transition process is that electrons transition from the bottom of the conduction band to the crystal field split energy band, emitting TM mode photons. As the emission wavelength of the deep ultraviolet LED decreases, the average Al component in the quantum well region becomes higher, the TE emission component decreases, and the TM emission component increases. In addition to the natural influence of the Al component, under compressive strain conditions in the AlGaN material, the TE emission component will increase. The above deep ultraviolet LED for adjusting the light-emitting angle improves the light-emitting angle of the deep ultraviolet LED chip by arranging a light-emitting angle adjustment layer between the multi-quantum well active region and the current spreading layer, applying sufficient compressive stress to the active region, thereby increasing the front emitted light of the deep ultraviolet LED and improving the sterilization efficiency.

[0034] For the second solution proposed by the present invention, the preparation method steps of the deep ultraviolet LED for adjusting the light-emitting angle include:

[0035] (1) Grow an AlN intrinsic layer. In this step, a low-temperature buffer layer in the AlN intrinsic layer is grown on the sapphire substrate at 400 - 800 °C, with a thickness of 10 - 50 nm.

[0036] (2) Raise the temperature to 1200 - 1400 °C and continue to grow on the low-temperature buffer layer in the AlN intrinsic layer to form an AlN intrinsic layer, with a total thickness of the AlN intrinsic layer being 500 - 4000 nm.

[0037] (3) Grow an n-type AlGaN intrinsic layer. In this step, lower the temperature to 800 - 1200 °C and grow an n-type AlGaN intrinsic layer on the AlN intrinsic layer, where the percentage of the Al component is 20 - 90%, and the thickness is 500 - 4000 nm.

[0038] (4) Grow a current spreading layer. In this step, maintain the temperature in step (3), stop introducing SiH4 doping, and grow a current spreading layer on the n-type AlGaN intrinsic layer, where the percentage of the Al component is 20 - 90%, and the thickness is 10 - 300 nm.

[0039] (5) Growing a light angle regulating layer. In this step, the temperature is raised to 800-1300° C., and a light angle regulating layer is grown on the current spreading layer. The thickness of the light angle regulating layer is 0.1-500 nm.

[0040] (6) Growing a multi-quantum well active layer. In this step, the temperature is lowered to 700-1100° C., and a multi-quantum well active layer is grown on the light angle control layer, wherein the quantum well thickness of the multi-quantum well active layer is 0.1-5 nm and the Al component percentage in the quantum well is 20-90%, and the quantum barrier thickness is 0.1-20 nm and the Al component percentage in the barrier is 30-100%.

[0041] (7) Growth of electron blocking layer: In this step, an electron blocking layer is grown on the multi-quantum well active layer at 700-1100° C., with a thickness of 1-50 nm and an Al component percentage of 10-100%.

[0042] (8) Growth of p-type AlGaN hole injection layer: In this step, a p-type AlGaN hole injection layer is grown on the electron blocking layer at 700-1100°C, with an Al component percentage of 10-100%, a thickness of 1-50 nm, and Mg as a p-type dopant.

[0043] (9) Growth of p-type GaN contact layer: In this step, a p-type GaN contact layer is grown on the p-type AlGaN hole injection layer at 400-900° C. with a thickness of 1-20 nm, and Mg is used as a p-type dopant.

[0044] In the above preparation steps, the growth temperature of the light output angle control layer in step (5) is T0, the growth temperature of the current spreading layer in step (4) is T1, and the growth temperature of the multi-quantum well active layer in step (6) is T2, and the three satisfy: T0≥T2≥T1; the amount of ammonia used in the light output angle control layer in step (5) is N0, the amount of ammonia used in the current spreading layer in step (4) is N1, and the amount of ammonia used in the multi-quantum well active layer in step (6) is N2, and the three satisfy: N0≤N1≤N2.

[0045] Since the method for preparing the deep ultraviolet LED with adjustable light emission angle in the second solution is used to prepare the deep ultraviolet LED with adjustable light emission angle in the first solution, the structure and function of the deep ultraviolet LED with adjustable light emission angle in the two solutions should remain consistent.

[0046] The performance of the deep ultraviolet LED with adjustable light output angle is characterized by a specific embodiment below, and an analysis is performed based on the characterization results.

[0047] Example 1

[0048] In this embodiment, the steps for fabricating a deep ultraviolet LED for regulating the light-emitting angle are as follows:

[0049] (1) Grow a buffer layer in the AlN intrinsic layer on a sapphire substrate at 600 °C, with a thickness of 25 nm.

[0050] (2) Raise the temperature to 1200 °C and grow an AlN intrinsic layer on the buffer layer in the AlN intrinsic layer. The total thickness of the AlN intrinsic layer is 1000 nm.

[0051] (3) Lower the temperature to 1000 °C and grow an n-type AlGaN intrinsic layer on the AlN intrinsic layer, where the percentage of Al component is 50%, and the thickness is 1000 nm.

[0052] (4) Maintain 1000 °C, stop introducing SiH4 doping, and grow a current spreading layer on the n-type AlGaN intrinsic layer, where the percentage of Al component is 70%, and the thickness is 100 nm.

[0053] (5) Raise the temperature to 1200 °C and grow a light-emitting angle regulating layer on the current spreading layer. The light-emitting angle regulating layer is a single-layer AlGaN structure, where the percentage of Al component is 90%, and the thickness is 100 nm.

[0054] (6) Lower the temperature to 900 °C and grow a multi-quantum well active layer on the light angle regulating layer. The quantum well thickness of the multi-quantum well active layer is 1 nm and the percentage of Al component in the quantum well is 50%. The quantum barrier thickness is 2 nm and the percentage of Al component in the barrier is 60%.

[0055] (7) Grow an electron blocking layer on the multi-quantum well active layer at 900 °C, with a thickness of 10 nm and the percentage of Al component being 40%.

[0056] (8) Grow a p-type AlGaN hole injection layer on the electron blocking layer at 900 °C. The percentage of Al component is 40%, the thickness is 20 nm, and Mg is used as the p-type dopant.

[0057] (9) Grow a p-type GaN contact layer on the p-type AlGaN hole injection layer at 600 °C, with a thickness of 10 nm, and Mg is used as the p-type dopant.

[0058] Example 2

[0059] In this embodiment, based on the fabrication steps of Example 1, only change step (5) above to: Raise the temperature to 1200 °C and grow a light-emitting angle regulating layer on the current spreading layer. The light-emitting angle regulating layer is Al y Ga 1-y N / Al z Ga 1-zAn N multi-layer periodic structure with a period of 50, where Al y Ga 1-y The Al component percentage of the N layer is 95% and the thickness is 1 nm; Al z Ga 1-z The Al component percentage of the AlGaN layer is 85% and the thickness is 1 nm. Other steps are the same as those in Example 1.

[0060] Comparative Example 1

[0061] In this comparative example, based on the preparation steps of Example 1, only the above step (5) is changed to: heating to 1200 °C, and growing a light angle control layer on the current spreading layer. The light angle control layer is a single-layer AlGaN structure with an Al component percentage of 70% and a thickness of 1 nm; other steps are the same as those in Example 1.

[0062] Comparative Example 2

[0063] In this comparative example, based on the preparation steps of Example 1, only the above step (5) is changed to: heating to 1200 °C, and growing a light angle control layer on the current spreading layer. The light angle control layer is Al y Ga 1-y N / Al z Ga 1-z An N multi-layer periodic structure with a period of 50, where Al y Ga 1-y The Al component percentage of the N layer is 95% and the thickness is 1 nm; Al z Ga 1-z The Al component percentage of the AlGaN layer is 85% and the thickness is 1 nm. Other steps are the same as those in Example 1.

[0064] Comparative Example 3

[0065] In this comparative example, a test sample is prepared by using a traditional deep ultraviolet LED preparation process, and the light angle control layer is not introduced into this sample.

[0066] The far-field light emission distribution and the light output angle of the above Examples 1-2 and Comparative Examples 1-3 are statistically analyzed, and the results are shown in Table 1 and Appendix Figure 2 As shown, the radiation intensity at 90° represents the light output amount on the front of the sample. The higher the radiation intensity at 90°, the better the front light output effect. Combining Table 1 and Appendix Figure 2 The data shown can be known:

[0067] 1) Comparing Examples 1-2 with Comparative Example 3 shows that for the deep ultraviolet LED with an adjusted light emission angle prepared by the method of the present invention, whether the introduced light emission angle adjustment layer is a single-layer AlGaN structure or a multi-periodic AlGaN structure, its light emission effect is better than that of traditional deep ultraviolet LEDs. At the same time, comparing Example 1 with Example 2, it can be seen that for Example 2 with an Al y Ga 1-y N / Al z Ga 1-z N multi-periodic structure as the light emission angle adjustment layer, its light emission effect is better than that of Example 1 with a single-layer Al x Ga 1-x N structure. The reason is that compared with the single-layer structure, the superlattice structure can better provide compressive stress, so that the multi-periodic structure can obtain a better front light emission effect; therefore, when introducing the light emission angle adjustment layer, the design method of the multi-periodic structure is more preferred.

[0068] 2) Comparing Example 1 with Comparative Example 1 and Example 2 with Comparative Example 2, it can be seen that the light emission effect of Comparative Example 1 is inferior to that of Example 1, and the light emission effect of Comparative Example 2 is also inferior to that of Example 2; the reason is that in the preparation process of the current spreading layer, the light emission angle adjustment layer, and the multi-quantum well active layer in Comparative Examples 1 and 2, the defined relationship of the Al component percentage among the three is exceeded; thus indicating that in the preparation of the current spreading layer, the light emission angle adjustment layer, and the multi-quantum well active layer, the defined relationship of the Al component percentage needs to be satisfied to obtain a better front light emission effect.

[0069] Table 1

[0070]

[0071] Differing from the prior art, the present invention provides a deep ultraviolet LED with an adjusted light emission angle and a preparation method thereof. By introducing a light emission angle adjustment layer between the multi-quantum well active layer and the current spreading layer, the compressive stress on the multi-quantum well active layer is increased, the front light emission amount of the deep ultraviolet LED is increased, the light emission angle of the deep ultraviolet LED is improved, and thus the improvement of the ultraviolet sterilization efficiency is realized.

[0072] The above-described embodiments merely represent the implementation manners of the present invention, and their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent shall be subject to the appended claims.

Claims

1. A deep ultraviolet LED for regulating the light-emitting angle, characterized in that, The deep ultraviolet LED for regulating the light-emitting angle includes a sapphire substrate, an AlN intrinsic layer, an n-type AlGaN intrinsic layer, a current spreading layer, a light-emitting angle regulating layer, a multi-quantum well active layer, an electron blocking layer, a p-type AlGaN hole injection layer, and a p-type GaN contact layer which are sequentially stacked and arranged; Among them, the light-emitting angle control layer is Al x Ga 1-x When it is a single-layer structure of N, the thickness of the light-emitting angle control layer is 0.1 nm to 500 nm; the percentage of Al component in the current spreading layer is a, the percentage of Al component in the quantum barrier of the multi-quantum well active layer is b, and the percentage of Al component in the quantum well of the multi-quantum well active layer is c, satisfying x≥a and x≥b + 20%≥c + 5%; The light-emitting angle control layer is Al y Ga 1-y N / Al z Ga 1-z N multi-layer periodic structure, the thickness of the Al y Ga 1-y N layer is 0.1 nm to 200 nm, and the thickness of the Al z Ga 1-z N layer is 0.1 nm to 100 nm; the percentage of Al component in the current spreading layer is a, the percentage of Al component in the quantum barrier of the multi-quantum well active layer is b, and the percentage of Al component in the quantum well of the multi-quantum well active layer is c, satisfying y - 5% ≥ z ≥ a and y - 5% ≥ z ≥ b + 20% ≥ c + 5%.

2. The deep ultraviolet LED for regulating the light-emitting angle according to claim 1, wherein The doping concentration of the light-emitting angle regulation layer is 1×10 12 ~1×10 22 cm -3 .

3. A preparation method of a deep ultraviolet LED for regulating the light-emitting angle as described in any one of claims 1 to 2, characterized in that, It includes the following steps: (1) Under the condition of 400~800 °C, grow a buffer layer in the AlN intrinsic layer on the sapphire substrate, with a thickness of 10~50 nm; (2) Raise the temperature to 1200~1400 °C, and grow an AlN intrinsic layer on the buffer layer in the AlN intrinsic layer. The total thickness of the AlN intrinsic layer is 500~4000 nm; (3) Lower the temperature to 800~1200 °C, and grow an n-type AlGaN intrinsic layer on the AlN intrinsic layer, where the percentage of Al component is 20~90%, and the thickness is 500~4000 nm; (4) Maintain the temperature in step (3), stop introducing SiH4 doping, and grow a current spreading layer on the n-type AlGaN intrinsic layer, where the percentage of Al component is 20~90%, and the thickness is 10~300 nm; (5) Raise the temperature to 800~1300 °C, and grow a light-emitting angle regulating layer on the current spreading layer; (6) Lower the temperature to 700~1100 °C, and grow a multi-quantum well active layer on the light-emitting angle regulating layer. The quantum well thickness of the multi-quantum well active layer is 0.1~5 nm and the percentage of Al component in the quantum well is 20~90%. The quantum barrier thickness is 0.1~20 nm and the percentage of Al component in the barrier is 30~100%; (7) Under the condition of 700~1100 °C, grow an electron blocking layer on the multi-quantum well active layer, with a thickness of 1~50 nm, and the percentage of Al component is 10~100%; (8) Under the condition of 700~1100 °C, grow a p-type AlGaN hole injection layer on the electron blocking layer, with the percentage of Al component being 10-100%, a thickness of 1~50 nm, and use Mg as the p-type dopant; (9) Under the condition of 400~900 °C, grow a p-type GaN contact layer on the p-type AlGaN hole injection layer, with a thickness of 1~20 nm, and use Mg as the p-type dopant.

4. The preparation method of the deep ultraviolet LED for regulating the light-emitting angle according to claim 3, characterized in that, The growth temperature of the light-emitting angle regulating layer in step (5) is T0, the growth temperature of the current spreading layer in step (4) is T1, and the growth temperature of the multi-quantum well active layer in step (6) is T2. The three satisfy: T0≥T2≥T1.

5. The preparation method of the deep ultraviolet LED for regulating the light-emitting angle according to claim 3, characterized in that, The ammonia usage amount of the light-emitting angle regulating layer in step (5) is N0, the ammonia usage amount of the current spreading layer in step (4) is N1, and the ammonia usage amount of the multi-quantum well active layer in step (6) is N2. The three satisfy: N0≤N1≤N2.

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