Multi-wavelength light-emitting ultraviolet LED and preparation method thereof

Abstract

The invention relates to the technical field of ultraviolet LEDs, and provides a multi-wavelength light-emitting ultraviolet LED and a preparation method thereof. The multi-wavelength light-emitting ultraviolet LED comprises a substrate, and an AlN template layer, an AlN thin film layer, an N-type intensity adjusting layer, an n-AlGaN layer, a quantum well light-emitting layer, an electron blocking layer, a P-type AlGaN layer and a P-type ohmic contact layer which are positioned on the surface of the substrate and are sequentially stacked, the quantum well light-emitting layer comprises at least two quantum well light-emitting layers with different light-emitting wavelengths, and the structures and growth temperatures of the quantum well light-emitting layers are different; according to the invention, the light emission of the ultraviolet LED with different wavelengths can be realized by changing the structure of the potential well layer without changing the thickness and components of the quantum well light-emitting layer; by adjusting the thickness of the n-AlN layer in the N-type intensity adjusting layer, the stress of the quantum well light-emitting layer is further influenced, and the relative intensity of ultraviolet light with different wavelengths is adjusted, so that various different application requirements are met.

Description

Technical Field

[0001] The present invention relates to the technical field of ultraviolet LEDs, and particularly to a multi-wavelength emitting ultraviolet LED and a preparation method thereof. Background Art

[0002] Ultraviolet disinfection technology has been widely used due to advantages such as being clean and environmentally friendly and not producing disinfection by-products. As a new generation of ultraviolet light source, AlGaN-based light-emitting diodes (LEDs) have great development potential and application markets in the fields of air and water purification, biochemical detection, sterilization and disinfection, etc. because of their environmental friendliness, small size, long lifespan, and adjustable emission wavelength, and have attracted great attention and strong interest from researchers. The emission wavelength of aluminum gallium nitride (AlGaN)-based deep ultraviolet light-emitting diodes (LEDs) can cover the ultraviolet band range of 200 - 365 nm by adjusting the Al component size in the AlGaN active region. Among them, UVC ultraviolet light with an emission wavelength between 200 and 280 nm can be widely used in the sterilization and disinfection of object surfaces and fluids such as air and water; while UVB band ultraviolet light with an emission wavelength between 280 nm and 320 nm has great application potential in water purification, skin disease treatment, and auxiliary growth of animals and plants.

[0003] In recent years, ultraviolet LEDs have developed rapidly, and among them, 230 nm far ultraviolet LEDs with biocompatible characteristics have also received extensive attention. Ultraviolet LEDs face problems such as difficult carrier injection, low radiative recombination efficiency, and low light extraction efficiency. These problems result in generally low photoelectric conversion efficiency of the devices, and there is a trend that the photoelectric conversion efficiency rapidly decreases as the wavelength becomes shorter.

[0004] Currently, most AlGaN-based ultraviolet LEDs emit single-wavelength light. If multi-wavelength ultraviolet emission is to be achieved, ultraviolet LED chips with different wavelengths need to be integrated, which increases the working difficulty and economic cost. Therefore, developing an AlGaN-based ultraviolet LED epitaxial structure with multiple bands and then realizing an ultraviolet LED chip with multi-wavelength emission has a promoting significance for realizing an ultraviolet LED with multiple functions. At the same time, the size of the ultraviolet LED disinfection device can be greatly simplified and the cost can be reduced. Summary of the Invention

[0005] Aiming at the above deficiencies, the purpose of the present invention is to provide a multi-wavelength emitting ultraviolet LED that can achieve multi-wavelength emission and adjustable emission intensity and a preparation method thereof.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a multi-wavelength light-emitting ultraviolet LED, comprising: a substrate and an AlN template layer, an AlN thin film layer, an N-type intensity adjustment layer, an n-AlGaN layer, a quantum well light-emitting layer, an electron blocking layer, a P-type AlGaN layer, and a P-type ohmic contact layer that are sequentially stacked on the surface of the substrate; Wherein, the quantum well light-emitting layer includes at least two quantum well light-emitting layers with different emission wavelengths.

[0007] Preferably, the N-type intensity adjustment layer is an n-Al x Ga 1-x N / n-AlN superlattice periodic structure layer; wherein, the thickness of n-AlN is 0.5 - 10 nm, the thickness of n-Al x Ga 1-x N is 5 - 50 nm, the thickness of the N-type intensity adjustment layer ≥ 0.5 μm, and 0.7 ≤ x < 1.

[0008] Preferably, the quantum well light-emitting layer includes a long-wavelength quantum well light-emitting layer, a first short-wavelength quantum well light-emitting layer, and a second short-wavelength quantum well light-emitting layer that are sequentially stacked; Wherein, the long-wavelength quantum well light-emitting layer is an AlGaN / AlN quantum well light-emitting layer, the thickness of the AlGaN well layer is 1 - 10 nm, the thickness of the AlN barrier layer is 2 - 10 nm, and the number of quantum well periods of the long-wavelength quantum well light-emitting layer is 1 - 3; The first short-wavelength quantum well light-emitting layer includes an AlGaN / AlN / AlGaN well layer and an AlN barrier layer, the thickness of the AlN barrier layer is 2 - 10 nm, the thickness of the AlGaN / AlN / AlGaN well layer is 2 - 8 nm, and the thickness of the AlN layer in the well layer is 0.1 - 1 nm; the number of quantum well periods of the first short-wavelength quantum well light-emitting layer is 1 - 3; The second short-wavelength quantum well light-emitting layer includes an AlGaN / AlN / AlGaN well layer and an AlN barrier layer, the thickness of the AlN barrier layer is 1 - 6 nm, the thickness of the AlGaN / AlN / AlGaN well layer is 1 - 4 nm, and the thickness of the AlN layer in the well layer is 0.1 - 1.5 nm; the number of quantum well periods of the second short-wavelength quantum well light-emitting layer is 1 - 3.

[0009] Preferably, the n-AlGaN layer includes an n-Al y Ga 1-y N layer and an n-Al z Ga 1-z N layer that are sequentially stacked; The thickness of the n-Al y Ga 1-y N layer is 200 - 1000 nm; The thickness of the n-Al z Ga1-z The thickness of the N layer is 0.1 - 100 nm; where 0.7 ≤ y ≤ x ≤ z < 1.

[0010] Preferably, the electron blocking layer is a P-AlGaN layer, the P-AlGaN layer is a P-AlaGa1-aN layer, 0.8 ≤ a < 1, and the thickness of the electron blocking layer is 0.5 - 50 nm.

[0011] Preferably, the P-type AlGaN layer is P-Al b Ga 1-b N layer, 0.5 ≤ b < 1, and the thickness of the P-type AlGaN layer is 50 - 500 nm.

[0012] Preferably, the P-type ohmic contact layer is a P-type GaN layer with a thickness of 0.5 - 50 nm; The thickness of the AlN thin film layer is 50 nm to 500 nm.

[0013] In a second aspect, the present invention also provides a method for manufacturing the multi-wavelength light-emitting ultraviolet LED described above, including the following steps: An AlN template layer, an AlN thin film layer, an N-type intensity adjustment layer, an n-AlGaN layer, a quantum well light-emitting layer, an electron blocking layer, a P-type AlGaN layer, and a P-type ohmic contact layer are sequentially grown on a substrate.

[0014] Preferably, an AlN template layer is grown on the substrate, and an AlN thin film layer is grown on the AlN template layer; the growth temperature of the AlN thin film layer is 1100 °C - 1300 °C; An N-type intensity adjustment layer is grown on the AlN thin film layer, and the N-type intensity adjustment layer is an n-Al x Ga 1-x N / n-AlN superlattice periodic structure layer, the growth temperature is 1000 °C - 1200 °C, and the carrier concentration is 5 × 10 17 ~1 × 10 19 cm -3 ; An n-AlGaN layer is grown on the N-type intensity adjustment layer, and the n-AlGaN layer includes sequentially stacked n-Al y Ga 1-y N layers, n-Al z Ga 1-z N layers, where the thickness of the n-Al y Ga 1-y N layer is 0.2 - 1 μm, the growth temperature is 1000 °C - 1200 °C, and the carrier concentration is 1 × 10 18 ~1 × 10 19 cm -3 ; n-Al z Ga 1-z The thickness of the n-AlGaN layer is 0.1 - 100 nm, the growth temperature is 1000 °C - 1200 °C, and the carrier concentration is 1×10 17 ~1×10 18 cm -3 ; A quantum well light-emitting layer is grown on the n-AlGaN layer; the quantum well light-emitting layer includes a long-wavelength quantum well light-emitting layer, a first short-wavelength quantum well light-emitting layer, and a second short-wavelength quantum well light-emitting layer stacked in sequence; wherein, the long-wavelength quantum well light-emitting layer is an AlGaN / AlN quantum well light-emitting layer, the thickness of the AlGaN well layer is 1 - 10 nm, the thickness of the AlN barrier layer is 2 - 10 nm, and the number of quantum well periods of the long-wavelength quantum well light-emitting layer is 1 - 3; The first short-wavelength quantum well light-emitting layer includes an AlGaN / AlN / AlGaN well layer and an AlN barrier layer, the thickness of the AlN barrier layer is 2 - 10 nm, the thickness of the AlGaN / AlN / AlGaN well layer is 2 - 8 nm, and the thickness of the AlN layer in the well layer is 0.1 - 1 nm; the number of quantum well periods of the first short-wavelength quantum well light-emitting layer is 1 - 3; The second short-wavelength quantum well light-emitting layer includes an AlGaN / AlN / AlGaN well layer and an AlN barrier layer, the thickness of the AlN barrier layer is 1 - 6 nm, the thickness of the AlGaN / AlN / AlGaN well layer is 1 - 4 nm, and the thickness of the AlN layer in the well layer is 0.1 - 1.5 nm; the number of quantum well periods of the second short-wavelength quantum well light-emitting layer is 1 - 3; The growth temperature of the long-wavelength quantum well light-emitting layer is 1000 °C - 1100 °C, the growth temperature of the first short-wavelength quantum well light-emitting layer is 1100 °C - 1150 °C, and the growth temperature of the second short-wavelength quantum well light-emitting layer is 1150 °C - 1170 °C; An electron blocking layer is grown on the quantum well light-emitting layer, the growth temperature is 1100 °C - 1200 °C, and the Mg doping concentration is 1×10 18 ~1×10 19 cm -3 ; A P-type AlGaN layer is grown on the electron blocking layer, the growth temperature is 800 °C - 1200 °C, and the Mg doping concentration is 2×10 18 ~1×10 19 cm -3 ; Preferably, a P-type ohmic contact layer is grown on the P-type AlGaN layer, the P-type ohmic contact layer is a P-type GaN layer, the growth temperature is 800 °C - 1100 °C, and the Mg doping concentration is 1×10 19 ~3×10 19 cm-3 ; Anneal under an inert atmosphere to obtain a multi-wavelength light-emitting ultraviolet LED.

[0015] The multi-wavelength light-emitting ultraviolet LED and its preparation method of the present invention have the following beneficial effects compared with the prior art: For the multi-wavelength light-emitting ultraviolet LED of the present invention, the quantum well light-emitting layer includes at least two quantum well light-emitting layers with different light-emitting wavelengths, and the structures and growth temperatures of the respective quantum well light-emitting layers are different; the present invention does not need to change the thickness and composition of the quantum well light-emitting layer to achieve ultraviolet LED light of different wavelengths, but realizes light emission of different wavelengths by changing the structure of the potential well layer; by adjusting the thickness of the n-AlN layer in the N-type intensity adjustment layer, the stress of the quantum well light-emitting layer is further affected, and the relative intensities of ultraviolet light of different wavelengths are adjusted to meet various different application requirements. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 It is a schematic structural diagram of the multi-wavelength light-emitting ultraviolet LED of the present invention; Figure 2 It is a schematic structural diagram of the quantum well light-emitting layer of the present invention; Figure 3 It is an AFM picture of the N-type intensity adjustment layer in Example 1; Figure 4 It is the hall test data of the N-type intensity adjustment layer in Example 1; Figure 5 The electroluminescence spectrum of the multi-wavelength light-emitting ultraviolet LED in Example 1; Figure 6 The electroluminescence spectrum of the multi-wavelength light-emitting ultraviolet LED in Example 2; Figure 7 The electroluminescence spectrum of the multi-wavelength light-emitting ultraviolet LED in Example 3. Detailed Embodiments

[0018] The following will combine the embodiments of the present invention to clearly and completely describe the technical solutions 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 fall within the scope of protection of the present invention.

[0019] It should be noted that like reference numerals and letters refer to like items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0020] In the description of the present invention, it should be understood that relational terms such as "upper" indicating orientation or position are based on the orientation or position shown in the figures, or the orientation or position in which the product of the invention is customarily placed during use, or the orientation or position commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0021] The following will be described in detail respectively. It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments. In addition, in the description of the present application, the term "comprising" means "including but not limited to". The various embodiments of the present invention may exist in a range form; it should be understood that the description in a range form is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the counted range, such as 1, 2, 3, 4, 5, and 6, which applies regardless of the range. In addition, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0022] The present invention provides a multi-wavelength light-emitting ultraviolet LED, as Figure 1 shown, comprising: a substrate 1, and an AlN template layer 2, an AlN thin film layer 3, an N-type intensity adjustment layer 4, an n-AlGaN layer 5, a quantum well light-emitting layer 6, an electron blocking layer 7, a P-type AlGaN layer 8, and a P-type ohmic contact layer 9 that are sequentially stacked on the surface of the substrate 1; wherein, the quantum well light-emitting layer 6 includes at least two quantum well light-emitting layers with different emission wavelengths.

[0023] The multi-wavelength emitting ultraviolet LED of the present invention, the quantum well light-emitting layer 6 includes at least two quantum well light-emitting layers with different emission wavelengths, and the structures of the respective quantum well light-emitting layers are different; the present invention does not need to change the thickness and composition of the quantum well light-emitting layer to achieve ultraviolet LED light with different wavelengths, but realizes different ultraviolet light emission wavelengths by changing the structure of the quantum well light-emitting layer; by adjusting the thickness of the n-AlN layer in the N-type intensity adjustment layer 4, the stress of the quantum well light-emitting layer 6 is affected, and the relative intensities of different wavelength ultraviolet lights are adjusted to meet various different application requirements.

[0024] The multi-wavelength emitting ultraviolet LED of the present invention, the structure of the quantum well light-emitting layer 6 includes at least two quantum well light-emitting layers with different emission wavelengths, and the structures of the respective quantum well light-emitting layers are different. The present invention realizes the emission of different ultraviolet wavelengths through different quantum well structures and different growth conditions, and realizes the emission of different ultraviolet wavelengths and the relative emission intensity by adjusting the thickness of the n-AlN layer in the N-type intensity adjustment layer; the quantum well light-emitting layer adopts a thin barrier design, which can reduce the barrier height of holes in the barrier region, enhance the tunneling effect of holes, weaken the quantum confinement effect, make the energy band structure closer to the "flat band" state, and is conducive to promoting the directional transport of holes to the first quantum well. It is conducive to realizing multi-band emission of ultraviolet LEDs in the range of 222 nm to 350 nm. Using the multi-wavelength emitting ultraviolet LED of the present invention, the effective combination of the surface disinfection function and air disinfection of objects can be realized, and the ultraviolet light source with a wavelength of 222 nm has weak penetration, which can minimize the impact on the human body during irradiation, and the applicable scenarios are more extensive.

[0025] In some embodiments, the N-type intensity adjustment layer 4 is an n-Al x Ga 1-x N / n-AlN superlattice periodic structure layer; that is, the N-type intensity adjustment layer 4 includes an n-Al x Ga 1-x N layer and an n-AlN layer, and the n-Al x Ga 1-x N layer and the n-AlN layer are arranged alternately in sequence, wherein the thickness of the n-AlN layer is 0.5 to 10 nm, and the thickness of the n-Al x Ga 1-x N is 5 to 50 nm, the thickness of the N-type intensity adjustment layer is ≥0.5 μm, and 0.7 ≤ x < 1. By adjusting the thickness of the n-AlN layer in the N-type intensity adjustment layer 4, the stress of the quantum well light-emitting layer 6 is affected, and the relative intensities of different wavelength ultraviolet lights are adjusted.

[0026] In some embodiments, as Figure 2 shown, the quantum well light-emitting layer 6 includes a long-wavelength quantum well light-emitting layer 61, a first short-wavelength quantum well light-emitting layer 62, and a second short-wavelength quantum well light-emitting layer 63 stacked in sequence; Among them, the long-wavelength quantum well light-emitting layer 61 is an AlGaN / AlN quantum well light-emitting layer, that is, an AlGaN well layer 611 and an AlN barrier layer 612. The thickness of the AlGaN well layer 611 is 1 - 10 nm, the thickness of the AlN barrier layer 612 is 2 - 10 nm, and the number of quantum well periods of the long-wavelength quantum well light-emitting layer 61 is 1 - 3; The first short-wavelength quantum well light-emitting layer 62 includes an AlGaN / AlN / AlGaN well layer and an AlN barrier layer. That is, the AlGaN / AlN / AlGaN well layer in the first short-wavelength quantum well light-emitting layer 62 includes an AlGaN layer, an AlN layer, and an AlGaN layer, corresponding to Figure 2 the numbers 621, 622, and 623 in it respectively. The AlN barrier layer in the first short-wavelength quantum well light-emitting layer 62 is Figure 2 the number 624 in it; the thickness of the AlGaN / AlN / AlGaN well layer in the first short-wavelength quantum well light-emitting layer 62 is 2 - 8 nm. Further, the thickness of the AlN layer in the AlGaN / AlN / AlGaN well layer is 0.1 - 1 nm, and the thickness of the AlN barrier layer is 2 - 10 nm; the number of quantum well periods of the first short-wavelength quantum well light-emitting layer is 1 - 3; and in the AlGaN / AlN / AlGaN well layer of the first short-wavelength quantum well light-emitting layer 62, the Al content in the two AlGaN layers can be the same or different; The second short-wavelength quantum well light-emitting layer 63 includes an AlGaN / AlN / AlGaN well layer and an AlN barrier layer. The AlGaN / AlN / AlGaN well layer in the second short-wavelength quantum well light-emitting layer 63 includes an AlGaN layer, an AlN layer, and an AlGaN layer, corresponding to Figure 2 the numbers 631, 632, and 633 in it respectively. The AlN barrier layer in the second short-wavelength quantum well light-emitting layer 63 is Figure 2 the number 634 in it; the thickness of the AlN barrier layer is 1 - 6 nm, the thickness of the AlGaN / AlN / AlGaN well layer in the second short-wavelength quantum well light-emitting layer 63 is 1 - 4 nm. Further, the thickness of the AlN layer in the AlGaN / AlN / AlGaN well layer is 0.1 - 1.5 nm; the number of quantum well periods of the second short-wavelength quantum well light-emitting layer 63 is 1 - 3. And in the AlGaN / AlN / AlGaN well layer of the first short-wavelength quantum well light-emitting layer 63, the Al content in the two AlGaN layers can be the same or different.

[0027] In some embodiments, the n-AlGaN layer 5 includes successively stacked n-Al y Ga 1-y N layer, n-Al z Ga 1-z N layer; n-Al y Ga 1-yThe thickness of the N layer is 200 to 1000 nm; n-Al z Ga 1-z The thickness of the N layer is 0.1 to 100 nm; Where 0.7 ≤ y ≤ x ≤ z < 1.

[0028] In some embodiments, the electron blocking layer 7 is a P-AlGaN layer, and the P-AlGaN layer is a P-Al a Ga 1-a N layer, 0.8 ≤ a < 1, and the thickness of the electron blocking layer 7 is 0.5 to 50 nm.

[0029] In some embodiments, the thickness of the P-type AlGaN layer 8 is 50 to 500 nm, and the P-type AlGaN layer is a P-Al b Ga 1-b N layer, 0.5 ≤ b < 1.

[0030] In some embodiments, the P-type ohmic contact layer 9 is a P-type GaN layer with a thickness of 0.5 to 50 nm.

[0031] Specifically, from the P-type AlGaN layer 8 to the P-type GaN layer, the Al component gradually changes from 0.8 to 1, and the Al element changes from present to absent.

[0032] In some embodiments, the thickness of the AlN thin film layer 3 is 50 nm to 500 nm.

[0033] In some embodiments, the growth temperature of the long-wavelength quantum well light-emitting layer 61 is T1, the growth temperature of the first short-wavelength quantum well light-emitting layer 62 is T2, and the growth temperature of the second short-wavelength quantum well light-emitting layer 63 is T3. Where 1000 °C ≤ T1 < T2 < T3 ≤ 1170 °C.

[0034] In some embodiments, the substrate 1 includes any one of a sapphire substrate, a silicon carbide substrate, a silicon substrate, a GaN substrate, and an AlN substrate.

[0035] The multi-wavelength light-emitting ultraviolet LED of the present invention has a quantum well light-emitting layer 6 structure including at least two quantum well light-emitting layers with different light-emitting wavelengths, and the structures of the respective quantum well light-emitting layers are different; further, the quantum well light-emitting layer 6 includes a long-wavelength quantum well light-emitting layer 61, a first short-wavelength quantum well light-emitting layer 62, and a second short-wavelength quantum well light-emitting layer 63 stacked in sequence. The growth temperature of the long-wavelength quantum well light-emitting layer 61 is T1, the growth temperature of the first short-wavelength quantum well light-emitting layer 62 is T2, and the growth temperature of the second short-wavelength quantum well light-emitting layer 63 is T3, where 1000°C ≤ T1 < T2 < T3 ≤ 1170°C; the present invention realizes different ultraviolet light-emitting wavelengths through different quantum well light-emitting layer 6 structures and different growth temperatures, and realizes different relative intensities of ultraviolet light emission by adjusting the thickness of the n-AlN layer in the N-type intensity adjustment layer. Using this epitaxial technology, an effective combination of surface disinfection function (222 nm) and air disinfection can be achieved. The 222 nm ultraviolet light source has weak penetration, can minimize the impact on the human body during irradiation, and has a wider range of applicable scenarios.

[0036] Based on the same inventive concept, the present invention also provides a preparation method for the above multi-wavelength light-emitting ultraviolet LED, including the following steps: Prepare an AlN template layer 2 on a substrate 1, and sequentially grow an AlN thin film layer 3, an N-type intensity adjustment layer 4, an n-AlGaN layer 5, a quantum well light-emitting layer, an electron blocking layer 7, a P-type AlGaN layer 8, and a P-type ohmic contact layer 9 on the AlN template layer.

[0037] In some embodiments, the AlN thin film layer, the AlN template layer, and the AlN layer are deposited using ammonia gas and an aluminum source as raw materials. The aluminum source is preferably an organoaluminum compound, more preferably trimethylaluminum, and is deposited by MOCVD (metalorganic chemical vapor deposition).

[0038] In some embodiments, the n-AlGaN layer, n-Al x Ga 1-x N layer is grown using TMAl (trimethylaluminum), TMGa (trimethylgallium), and NH3 (ammonia gas) as the Al source, Ga source, and N source respectively, and SiH4 (silane) as the doping source.

[0039] In some embodiments, the n-AlN layer is grown using TMAl (trimethylaluminum) and NH3 as the Al source and N source respectively, and SiH4 as the doping source.

[0040] In some embodiments, the AlGaN layer is grown using TMAl (trimethylaluminum), TMGa (trimethylgallium), and NH3 as the Al source, Ga source, and N source respectively.

[0041] In some embodiments, the P-type GaN layer is grown using trimethylgallium (TMGa) and NH3 as the Ga source and N source respectively, and bis(cyclopentadienyl)magnesium (Cp2Mg) as the doping source.

[0042] In some embodiments, the P-AlGaN layer is grown using trimethylaluminum (TMAl), trimethylgallium (TMGa) and NH3 as the Al source, Ga source and N source respectively, and bis(cyclopentadienyl)magnesium (Cp2Mg) as the doping source.

[0043] In some embodiments, a method for fabricating a multi-wavelength light-emitting ultraviolet LED includes the following steps: S1. An AlN thin film layer is grown on a substrate having an AlN template layer; specifically, the AlN thin film layer is deposited by metalorganic chemical vapor deposition (MOCVD), using trimethylaluminum (TMAl) or triethylaluminum (TEAl) as the Al source, NH3 as the nitrogen source, and H2 as the carrier gas; the growth temperature of the AlN thin film layer is controlled at 1100°C to 1300°C, and the pressure is controlled between 30 and 100 mbar, finally obtaining a high-quality, flat-surface AlN thin film layer; S2. An N-type intensity adjustment layer is grown on the AlN thin film layer, and the N-type intensity adjustment layer is an n-Al x Ga 1-x N / n-AlN superlattice periodic structure layer, where 0.7 ≤ x < 1, and the carrier concentration of the N-type intensity adjustment layer is 5×10 17 ~1×10 19 cm -3 ; specifically, the N-type intensity adjustment layer is deposited by MOCVD, using TMAl or TEAl as the Al source, trimethylgallium (TMGa) or triethylgallium (TEGa) as the Ga source, NH3 as the nitrogen source, SiH4 as the doping source, and H2 as the carrier gas, and the growth temperature is controlled between 1000°C and 1200°C, and the pressure is controlled between 30 and 100 mbar; S3. An n-AlGaN layer is grown on the N-type intensity adjustment layer, and the n-AlGaN layer includes an n-Al y Ga 1-y N layer and an n-Al z Ga 1-z N layer stacked in sequence, where the thickness of the n-Al y Ga 1-y N layer is 0.2 to 1 μm, the growth temperature is 1000°C to 1200°C, and the carrier concentration is 1×10 18 ~1×10 19 cm -3 ; the n-Al z Ga 1-zThe thickness of the n-layer is 0.1 to 100 nm, the growth temperature is 1000 °C to 1200 °C, and the carrier concentration is 1×10 17 ~1×10 18 cm -3 , where 0.7 ≤ y ≤ x ≤ z < 1. Further preferably, 0.75 ≤ y ≤ z ≤ 0.9; specifically, the n-AlGaN layer is deposited by MOCVD, TMAl or TEAl is selected as the Al source, TMGa (trimethylgallium) or TEGa (triethylgallium) is selected as the Ga source, NH3 is used as the nitrogen source, SiH4 is used as the doping source, H2 is used as the carrier gas, and the pressure is controlled between 30 and 100 mbar; S4. Grow a quantum well light-emitting layer on the n-AlGaN layer; the quantum well light-emitting layer includes a long-wavelength quantum well light-emitting layer, a first short-wavelength quantum well light-emitting layer, and a second short-wavelength quantum well light-emitting layer stacked in sequence; among them, the long-wavelength quantum well light-emitting layer is an AlGaN / AlN quantum well light-emitting layer, the thickness of the AlGaN well layer is 1 to 10 nm, the thickness of the AlN barrier layer is 2 to 10 nm, and the number of quantum well periods of the long-wavelength quantum well light-emitting layer is 1 to 3; specifically, the long-wavelength quantum well light-emitting layer is deposited by MOCVD, TMAl or TEAl is selected as the Al source, TMGa (trimethylgallium) or TEGa (triethylgallium) is selected as the Ga source, NH3 is used as the nitrogen source, H2 is used as the carrier gas, and the pressure is controlled between 30 and 100 mbar; The first short-wavelength quantum well light-emitting layer includes an AlGaN / AlN / AlGaN well layer and an AlN barrier layer. The thickness of the AlN barrier layer is 2 to 10 nm, the thickness of the AlGaN / AlN / AlGaN well layer is 2 to 8 nm, and the thickness of the AlN layer in the well layer is 0.1 to 1 nm; the number of quantum well periods of the first short-wavelength quantum well light-emitting layer is 1 to 3; The second short-wavelength quantum well light-emitting layer includes an AlGaN / AlN / AlGaN well layer and an AlN barrier layer. The thickness of the AlN barrier layer is 1 to 6 nm, the thickness of the AlGaN / AlN / AlGaN well layer is 1 to 4 nm, and the thickness of the AlN layer in the well layer is 0.1 to 1.5 nm; the number of quantum well periods of the second short-wavelength quantum well light-emitting layer is 1 to 3; The growth temperature of the long-wavelength quantum well light-emitting layer is 1000 °C to 1100 °C, the growth temperature of the first short-wavelength quantum well light-emitting layer is 1100 °C to 1150 °C, and the growth temperature of the second short-wavelength quantum well light-emitting layer is 1150 °C to 1170 °C; S5. Grow an electron blocking layer with a thickness of 0.1 - 50 nm on the quantum well light-emitting layer. Specifically, the electron blocking layer is obtained by MOCVD deposition. Select TMAl or TEAl as the Al source, TMGa (trimethylgallium) or TEGa (triethylgallium) as the Ga source, NH3 as the nitrogen source, MgCp2 (magnesium bis(cyclopentadienyl)) as the doping source, and H2 as the carrier gas. Control the pressure between 50 - 200 mbar, the growth temperature is 1100 °C - 1200 °C, and the doping concentration of Mg is 1×10 18 ~1×10 19 cm -3 ; S6. Grow a P-type AlGaN layer with a thickness of 50 - 500 nm on the electron blocking layer. Specifically, the P-type AlGaN layer is obtained by MOCVD deposition. Select TMAl or TEAl as the Al source, TMGa (trimethylgallium) or TEGa (triethylgallium) as the Ga source, NH3 as the nitrogen source, MgCp2 (magnesium bis(cyclopentadienyl)) as the doping source, and H2 as the carrier gas. Control the pressure between 50 - 200 mbar, the growth temperature is 800 °C - 1200 °C, and the doping concentration of Mg is 2×10 18 ~1×10 19 cm -3 ; S7. Grow a P-type ohmic contact layer with a thickness of 0.1 - 50 nm on the P-type AlGaN layer. The P-type ohmic contact layer is a P-type GaN layer. Specifically, the P-type GaN layer is obtained by MOCVD deposition. Select TMGa (trimethylgallium) or TEGa (triethylgallium) as the Ga source, NH3 as the nitrogen source, MgCp2 (magnesium bis(cyclopentadienyl)) as the doping source, and H2 as the carrier gas. Control the pressure between 100 - 500 mbar, the growth temperature is 800 °C - 1100 °C, and the doping concentration of Mg is 1×10 19 ~3×10 19 cm -3 .

[0044] S8. Anneal under an inert atmosphere to obtain a multi-wavelength light-emitting ultraviolet LED.

[0045] In some embodiments, the annealing temperature is 700 °C - 900 °C, and the annealing time is 10 min - 40 min.

[0046] In some embodiments, the inert atmosphere includes any one of nitrogen, helium, neon, argon, etc.

[0047] In some embodiments, before depositing each layer on the substrate, the substrate is further treated. The treatment is specifically: using a mixed atmosphere of hydrogen and ammonia to clean the surface of the substrate at a temperature of 700 °C - 950 °C.

[0048] The multi-wavelength light-emitting ultraviolet LED of the present application and its manufacturing method will be further described below with specific embodiments. This part further explains the content of the present invention in combination with specific embodiments, but should not be construed as a limitation to the present invention. Unless otherwise specified, the technical means adopted in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0049] Example 1 The embodiment of the present application provides a multi-wavelength light-emitting ultraviolet LED, including: a sapphire substrate and an AlN template layer, an AlN thin film layer, an N-type intensity adjustment layer, an n-AlGaN layer, a quantum well light-emitting layer, an electron blocking layer, a P-type AlGaN layer, and a P-type ohmic contact layer that are sequentially stacked on the surface of the substrate; The thickness of the AlN template layer is 500 nm; The thickness of the AlN thin film layer is 50 nm; The N-type intensity adjustment layer is an n-Al 0.8 Ga 0.2 N / n-AlN superlattice periodic structure layer, the thickness of the n-AlN layer is 2 nm, and the thickness of the n-Al 0.8 Ga 0.2 N is 18 nm. The total thickness of the N-type intensity adjustment layer is 800 nm, and the carrier concentration of the N-type intensity adjustment layer is 5×10 17 cm -3 ; The n-AlGaN layer includes an n-Al 0.8 Ga 0.2 N layer and an n-Al 0.85 Ga 0.15 N layer stacked in sequence; the thickness of the n-Al 0.8 Ga 0.2 N layer is 200 nm, and the carrier concentration is 1×10 18 cm -3 ; the thickness of the n-Al 0.85 Ga 0.15 N layer is 20 nm, and the carrier concentration is 3×10 17 cm -3 ; The quantum well light-emitting layer includes a long-wavelength quantum well light-emitting layer, a first short-wavelength quantum well light-emitting layer, and a second short-wavelength quantum well light-emitting layer stacked in sequence; The long-wavelength quantum well light-emitting layer is an Al 0.3 Ga 0.7 N / AlN quantum well light-emitting layer. The thickness of the Al 0.3 Ga 0.7 N well layer is 2 nm, the thickness of the AlN barrier layer is 3 nm, and the number of quantum well periods of the long-wavelength quantum well light-emitting layer is 2; The first short-wavelength quantum well light-emitting layer includes Al 0.6 Ga 0.4 N / AlN / Al 0.6 Ga 0.4 N well layers and AlN barrier layers. The thickness of the AlN barrier layer is 2.5 nm, and Al 0.6 Ga 0.4 N / AlN / Al 0.6 Ga 0.4 The thicknesses of the N well layers are 1 nm / 0.5 nm / 1 nm respectively, and the number of quantum well periods of the first short-wavelength quantum well light-emitting layer is 2; The second short-wavelength quantum well light-emitting layer includes Al 0.6 Ga 0.4 N / AlN / Al 0.6 Ga 0.4 N well layers and AlN barrier layers. The thickness of the AlN barrier layer is 3 nm, and Al 0.6 Ga 0.4 N / AlN / Al 0.6 Ga 0.4 The thicknesses of the N well layers are 0.5 nm / 1 nm / 0.5 nm respectively, and the number of quantum well periods of the second short-wavelength quantum well light-emitting layer is 2; The electron blocking layer is a P-Al 0.85 Ga 0.15 N layer. The thickness of the electron blocking layer is 10 nm, and the Mg doping concentration is 1×10 18 ; The P-type AlGaN layer is a P-Al 0.6 Ga 0.4 N layer with a thickness of 50 nm and a Mg doping concentration of 2×10 18 ; The P-type ohmic contact layer is a P-type GaN layer with a thickness of 20 nm and a Mg doping concentration of 1×10 19 ; The preparation method of the above multi-wavelength light-emitting ultraviolet LED includes the following steps: S1. Select a sapphire substrate with an AlN template layer, and perform surface cleaning on the template substrate in a mixed atmosphere of hydrogen and ammonia at a temperature of 900 °C for 20 min; S2. Grow an AlN thin film layer on the AlN template layer with a thickness of 50 nm. Select TMAl (trimethylaluminum) as the Al source, NH3 as the nitrogen source, and H2 as the carrier gas. Control the growth temperature of the AlN thin film layer at 1100 °C, the pressure at 50 mbar, and the V / III ratio at 200 (i.e., the flow ratio of ammonia to trimethylaluminum is 200), and finally obtain a high-quality and flat-surface AlN thin film layer; S3. Grow an N-type intensity adjustment layer on the AlN thin film layer. The N-type intensity adjustment layer is n-Al0.8 Ga 0.2 GaN / n-AlN superlattice periodic structure layer, the thickness of the n-AlN layer is 2 nm, and the n-Al 0.8 Ga 0.2 N thickness is 18 nm, and the total thickness of the N-type intensity adjustment layer is 800 nm; n-Al 0.8 Ga 0.2 The growth temperatures of N / n-AlN are both 1050 °C. TMAl is selected as the Al source, TMGa is used as the Ga source, NH3 is used as the nitrogen source, SiH4 is used as the doping source, H2 is used as the carrier gas, and the pressure is controlled at 60 mbar. The carrier concentration of the N-type intensity adjustment layer is 5×10 17 ; S4. Grow an n-AlGaN layer on the N-type intensity adjustment layer. The n-AlGaN layer includes successively stacked n-Al 0.8 Ga 0.2 N layer, n-Al 0.85 Ga 0.15 N layer; n-Al 0.8 Ga 0.2 The thickness of the N layer is 200 nm, the growth temperature is 1050 °C, and the carrier concentration is 1×10 18 ; The thickness of the n-Al 0.85 Ga 0.15 N layer is 20 nm, the growth temperature is 1070 °C, and the carrier concentration is 3×10 17 ; TMA is selected as the Al source, TMGa is used as the Ga source, NH3 is used as the nitrogen source, SiH4 is used as the doping source, H2 is used as the carrier gas, and the pressure is controlled at 60 mba; S5. Grow a long-wavelength quantum well light-emitting layer, a first short-wavelength quantum well light-emitting layer, and a second short-wavelength quantum well light-emitting layer successively on the n-AlGaN layer; The long-wavelength quantum well light-emitting layer is an Al 0.3 Ga 0.7 N / AlN quantum well light-emitting layer. The thickness of the Al 0.3 Ga 0.7 N well layer is 2 nm, the thickness of the AlN barrier layer is 3 nm, and the number of quantum well periods of the long-wavelength quantum well light-emitting layer is 2; Al 0.3 Ga 0.7 The growth temperatures of N / AlN are both 1070 °C. TMAl is selected as the Al source, TMGa is used as the Ga source, NH3 is used as the nitrogen source, H2 is used as the carrier gas, and the pressure is controlled between 60 mbar; The first short-wavelength quantum well light-emitting layer includes Al 0.6 Ga 0.4 N / AlN / Al 0.6 Ga 0.4N-well layer, AlN barrier layer, the thickness of the AlN barrier layer is 2.5 nm, Al 0.6 Ga 0.4 N / AlN / Al 0.6 Ga 0.4 The thicknesses of the N-well layer are 1 nm / 0.5 nm / 1 nm respectively; the number of quantum well periods of the first short-wavelength quantum well light-emitting layer is 2; Al 0.6 Ga 0.4 N / AlN / Al 0.6 Ga 0.4 The growth temperatures of the N-well layer and the AlN barrier layer are both 1120 °C. TMAl is selected as the Al source, TMGa is selected as the Ga source, NH3 is selected as the nitrogen source, H2 is selected as the carrier gas, and the pressure is controlled at 60 mbar; The second short-wavelength quantum well light-emitting layer includes Al 0.6 Ga 0.4 N / AlN / Al 0.6 Ga 0.4 N-well layer, AlN barrier layer, the thickness of the AlN barrier layer is 3 nm, Al 0.6 Ga 0.4 N / AlN / Al 0.6 Ga 0.4 The thicknesses of the N-well layer are 0.5 nm / 1 nm / 0.5 nm respectively, and the number of quantum well periods of the second short-wavelength quantum well light-emitting layer is 2; Al 0.6 Ga 0.4 N / AlN / Al 0.6 Ga 0.4 The growth temperatures of the N-well layer and the AlN barrier layer are both 1150 °C. TMAl is selected as the Al source, TMGa is selected as the Ga source, NH3 is selected as the nitrogen source, H2 is selected as the carrier gas, and the pressure is controlled at 60 mbar; S6. Grow an electron blocking layer on the second short-wavelength quantum well light-emitting layer. The electron blocking layer is a P-Al 0.85 Ga 0.15 N layer. The thickness of the electron blocking layer is 10 nm, and the Mg doping concentration is 1×10 18 , select TMAl as the Al source, TMG as the Ga source, NH3 as the nitrogen source, MgCp2 as the doping source, H2 as the carrier gas, control the pressure at 100 mbar, and the growth temperature is 1100 °C; S7. Grow a P-Al layer with a thickness of 50 nm on the electron blocking layer 0.6 Ga 0.4 N layer, and the Mg doping concentration is 2×10 18 ; select TMAl as the Al source, TMGa as the Ga source, NH3 as the nitrogen source, MgCp2 as the doping source, H2 as the carrier gas, control the pressure at 100 mbar, and the growth temperature is 1100 °C; S8. A P-type ohmic contact layer grown on the P-type AlGaN layer is a P-type GaN layer with a thickness of 20 nm and an Mg doping concentration of 1×10 19 ; TMGa is selected as the Ga source, NH3 as the nitrogen source, MgCp2 as the doping source, and H2 as the carrier gas. The pressure is controlled at 120 mbar, and the growth temperature is 900 °C; S9. Anneal in a nitrogen environment at an annealing temperature of 900 °C for 10 minutes.

[0050] Example 2 The wavelength-emitting ultraviolet LED provided in this example is the same as that in Example 1, except that the N-type intensity adjustment layer is an n-Al 0.8 Ga 0.2 N / n-AlN superlattice periodic structure layer, the thickness of the n-AlN layer is 0.5 nm, and the n-Al 0.8 Ga 0.2 N has a thickness of 19.5 nm, the total thickness of the N-type intensity adjustment layer is 1000 nm, and the carrier concentration of the N-type intensity adjustment layer is 3×10 18 cm -3 ; The preparation method of the wavelength-emitting ultraviolet LED in Example 2 is the same as that in Example 1, except that step S3 is: growing an N-type intensity adjustment layer on the AlN thin film layer. The N-type intensity adjustment layer is an n-Al 0.8 Ga 0.2 N / n-AlN superlattice periodic structure layer, the thickness of the n-AlN layer is 0.5 nm, and the n-Al 0.8 Ga 0.2 N has a thickness of 19.5 nm, the total thickness of the N-type intensity adjustment layer is 1000 nm, the growth temperature is 1100 °C, and the carrier concentration of the N-type intensity adjustment layer is 3×10 18 cm -3 ; The rest are the same as those in Example 1.

[0051] Example 3 The embodiment of the present application provides a multi-wavelength emitting ultraviolet LED, including: a sapphire substrate and an AlN template layer, an AlN thin film layer, an N-type intensity adjustment layer, an n-AlGaN layer, a quantum well light-emitting layer, an electron blocking layer, a P-type AlGaN layer, and a P-type ohmic contact layer that are sequentially stacked on the surface of the substrate; The thickness of the AlN template layer is 500 nm; The thickness of the AlN thin film layer is 500 nm; The N-type intensity adjustment layer is an n-Al 0.8 Ga 0.2 N / n-AlN superlattice periodic structure layer, the thickness of the n-AlN layer is 0.5 nm, and the n-Al 0.8 Ga0.2 The thickness of N is 14.5 nm, the total thickness of the N-type intensity adjustment layer is 1005 nm, and the carrier concentration of the N-type intensity adjustment layer is 1×10 18 cm -3 ; The n-AlGaN layer includes successively stacked n-Al 0.8 Ga 0.2 N layer, n-Al 0.85 Ga 0.15 N layer; n-Al 0.8 Ga 0.2 The thickness of the N layer is 300 nm, and the carrier concentration is 1×10 18 cm -3 ; n-Al 0.85 Ga 0.15 The thickness of the N layer is 50 nm, and the carrier concentration is 1×10 17 cm -3 ; The quantum well light-emitting layer includes successively stacked long-wavelength quantum well light-emitting layers and first short-wavelength quantum well light-emitting layers; The long-wavelength quantum well light-emitting layer is an Al 0.65 Ga 0.45 N / AlN quantum well light-emitting layer, the thickness of the Al 0.65 Ga 0.45 N well layer is 2 nm, the thickness of the AlN barrier layer is 4 nm, and the number of quantum well periods of the long-wavelength quantum well light-emitting layer is 2; The first short-wavelength quantum well light-emitting layer includes Al 0.65 Ga 0.45 N / AlN / Al 0.65 Ga 0.45 N well layer, AlN barrier layer, the thickness of the AlN barrier layer is 4 nm, Al 0.65 Ga 0.45 N / AlN / Al 0.65 Ga 0.45 The thicknesses of the N well layers are 1 nm / 1 nm / 1 nm respectively, and the number of quantum well periods of the first short-wavelength quantum well light-emitting layer is 3; The electron blocking layer is a P-Al 0.8 Ga 0.2 N layer, the thickness of the electron blocking layer is 1 nm, and the Mg doping concentration is 1×10 18 ; The P-type AlGaN layer is a P-Al 0.6 Ga 0.4 N layer, the thickness is 100 nm, and the Mg doping concentration is 2×10 18 ; The P-type ohmic contact layer is a P-type GaN layer, the thickness is 20 nm, and the Mg doping concentration is 1×10 19 ; The preparation method of the above multi-wavelength light-emitting ultraviolet LED includes the following steps: S1. Select a sapphire substrate containing an AlN template layer, and use a mixed atmosphere of hydrogen and ammonia to clean the surface of the template substrate at a temperature of 900 °C for 5 minutes. S2. Grow an AlN thin film layer on the AlN template layer with a thickness of 500 nm; select TMAl (trimethylaluminum) as the Al source, NH3 as the nitrogen source, H2 as the carrier gas, control the growth temperature of the AlN thin film layer at 1250 °C, the pressure at 50 mbar, and the V / III ratio at 100 (i.e., the flow ratio of ammonia to trimethylaluminum is 100), and finally obtain a high-quality, flat-surface AlN thin film layer. S3. Grow an N-type intensity adjustment layer on the AlN thin film layer. The N-type intensity adjustment layer is an n-Al 0.8 Ga 0.2 N / n-AlN superlattice periodic structure layer. The thickness of the n-AlN layer is 0.5 nm, and the thickness of the n-Al 0.8 Ga 0.2 N is 14.5 nm. The total thickness of the N-type intensity adjustment layer is 1005 nm, and the carrier concentration of the N-type intensity adjustment layer is 1×10 18 cm -3 ; The growth temperatures of n-Al 0.8 Ga 0.2 N / n-AlN are both 1150 °C. Select TMAl as the Al source, TMGa as the Ga source, NH3 as the nitrogen source, SiH4 as the doping source, H2 as the carrier gas, and control the pressure at 60 mbar. S4. Grow an n-AlGaN layer on the N-type intensity adjustment layer. The n-AlGaN layer includes successively stacked n-Al 0.8 Ga 0.2 N layers and n-Al 0.85 Ga 0.15 N layers; The thickness of the n-Al 0.8 Ga 0.2 N layer is 300 nm, the growth temperature is 1050 °C, and the carrier concentration is 1×10 18 cm -3 ; The thickness of the n-Al 0.85 Ga 0.15 N layer is 50 nm, the growth temperature is 1070 °C, and the carrier concentration is 1×10 17 cm -3 ; Select TMA as the Al source, TMGa as the Ga source, NH3 as the nitrogen source, SiH4 as the doping source, H2 as the carrier gas, and control the pressure at 60 mba. S5. Grow a long-wavelength quantum well light-emitting layer and a first short-wavelength quantum well light-emitting layer on the n-AlGaN layer in sequence; The long-wavelength quantum well light-emitting layer is Al 0.65 Ga 0.45 N / AlN quantum well light-emitting layer, the thickness of the Al 0.65 Ga 0.45 N well layer is 2 nm, the thickness of the AlN barrier layer is 4 nm, and the number of quantum well periods of the long-wavelength quantum well light-emitting layer is 2; Al 0.65 Ga 0.45 The growth temperature of N / AlN is 1040 °C. Select TMAl as the Al source, TMGa as the Ga source, NH3 as the nitrogen source, and H2 as the carrier gas. The pressure is controlled between 60 mbar; The first short-wavelength quantum well light-emitting layer includes Al 0.65 Ga 0.45 N / AlN / Al 0.65 Ga 0.45 N well layer and AlN barrier layer. The thickness of the AlN barrier layer is 4 nm. Al 0.65 Ga 0.45 The thicknesses of the N / AlN / Al 0.65 Ga 0.45 N well layers are 1 nm / 1 nm / 1 nm respectively, and the number of quantum well periods of the first short-wavelength quantum well light-emitting layer is 3; Al 0.65 Ga 0.45 The growth temperature of the N / AlN / Al 0.65 Ga 0.45 N well layer and AlN barrier layer is 1150 °C. Select TMAl as the Al source, TMGa as the Ga source, NH3 as the nitrogen source, and H2 as the carrier gas. The pressure is controlled at 60 mbar; S6. Grow an electron blocking layer on the second short-wavelength quantum well light-emitting layer. The electron blocking layer is a P-Al 0.8 Ga 0.2 N layer. The thickness of the electron blocking layer is 1 nm, and the Mg doping concentration is 1×10 18 , select TMAl as the Al source, TMG as the Ga source, NH3 as the nitrogen source, MgCp2 as the doping source, and H2 as the carrier gas. The pressure is controlled at 100 mbar, and the growth temperature is 1120 °C; S7. Grow a P-Al layer with a thickness of 100 nm on the electron blocking layer 0.6 Ga 0.4 N layer, and the Mg doping concentration is 2×10 18 ; select TMAl as the Al source, TMGa as the Ga source, NH3 as the nitrogen source, MgCp2 as the doping source, and H2 as the carrier gas. The pressure is controlled at 100 mbar, and the growth temperature is 980 °C; S8. On the P-Al0.6 Ga 0.4 A P-type ohmic contact layer is grown on the N layer. The P-type ohmic contact layer is a P-type GaN layer with a thickness of 20 nm and a Mg doping concentration of 1×10 19 ; TMGa is selected as the Ga source, NH3 as the nitrogen source, MgCp2 as the doping source, and H2 as the carrier gas. The pressure is controlled at 120 mbar and the growth temperature is 950 °C; S9. Anneal in a nitrogen environment at an annealing temperature of 900 °C for an annealing time of 10 min.

[0052] Figure 3 is the AFM image of the N-type intensity adjustment layer in Example 1; Figure 4 is the hall test data of the N-type intensity adjustment layer in Example 1; Figure 5 The electroluminescence spectrum of the multi-wavelength light-emitting ultraviolet LED in Example 1.

[0053] Figure 6 The electroluminescence spectrum of the multi-wavelength light-emitting ultraviolet LED in Example 2.

[0054] Figure 7 The electroluminescence spectrum of the multi-wavelength light-emitting ultraviolet LED in Example 3.

[0055] From Figure 3 it can be seen that the surface of the N-type intensity adjustment layer n-Al 0.8 Ga 0.2 N / n-AlN in Example 1 is smooth; from Figure 4 it can be seen that the N-type intensity adjustment layer n-Al 0.8 Ga 0.2 N / n-AlN in Example 1 can achieve n-type doping.

[0056] From Figure 5 it can be seen that for the multi-wavelength light-emitting ultraviolet LED in Example 1, the ultraviolet light wavelengths emitted by the long-wavelength quantum well light-emitting layer, the first short-wavelength quantum well light-emitting layer, and the second short-wavelength quantum well light-emitting layer are 314 nm, 251 nm, and 223 nm respectively, and the intensity of the short-wavelength ultraviolet light with a wavelength of 251 nm is the strongest.

[0057] From Figures 6 - 7 it can be seen that the multi-wavelength light-emitting ultraviolet LED of the present invention can achieve multi-wavelength ultraviolet LED emission, and different emission wavelength intensities are achieved through the intensity adjustment layer.

[0058] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A multi-wavelength light-emitting ultraviolet LED, characterized in that, It includes a substrate, and an AlN template layer, an AlN thin film layer, an N-type intensity adjustment layer, an n-AlGaN layer, a quantum well light-emitting layer, an electron blocking layer, a P-type AlGaN layer, and a P-type ohmic contact layer that are sequentially stacked on the surface of the substrate; Among them, the quantum well light-emitting layer includes at least two quantum well light-emitting layers with different emission wavelengths.

2. The multi-wavelength light-emitting ultraviolet LED according to claim 1, wherein, The N-type intensity adjustment layer is an n-Al x Ga 1-x N / n-AlN superlattice periodic structure layer; wherein, the thickness of n-AlN is 0.5-10 nm, and the thickness of n-Al x Ga 1-x N is 5-50 nm, the thickness of the N-type intensity adjustment layer ≥ 0.5 μm, and 0.7 ≤ x < 1.

3. The multi-wavelength light-emitting ultraviolet LED according to claim 1, characterized in that, The quantum well light-emitting layer includes a long-wavelength quantum well light-emitting layer, a first short-wavelength quantum well light-emitting layer, and a second short-wavelength quantum well light-emitting layer that are sequentially stacked; Among them, the long-wavelength quantum well light-emitting layer is an AlGaN / AlN quantum well light-emitting layer, the thickness of the AlGaN well layer is 1-10 nm, the thickness of the AlN barrier layer is 2-10 nm, and the number of quantum well periods of the long-wavelength quantum well light-emitting layer is 1-3; The first short-wavelength quantum well light-emitting layer includes an AlGaN / AlN / AlGaN well layer and an AlN barrier layer. The thickness of the AlN barrier layer is 2-10 nm, the thickness of the AlGaN / AlN / AlGaN well layer is 2-8 nm, and the thickness of the AlN layer in the well layer is 0.1-1 nm; the number of quantum well periods of the first short-wavelength quantum well light-emitting layer is 1-3; The second short-wavelength quantum well light-emitting layer includes an AlGaN / AlN / AlGaN well layer and an AlN barrier layer. The thickness of the AlN barrier layer is 1-6 nm, the thickness of the AlGaN / AlN / AlGaN well layer is 1-4 nm, and the thickness of the AlN layer in the well layer is 0.1-1.5 nm; the number of quantum well periods of the second short-wavelength quantum well light-emitting layer is 1-3.

4. The multi-wavelength light-emitting ultraviolet LED according to claim 1, wherein The n-AlGaN layer includes an n-Al y Ga 1-y N layer, an n-Al z Ga 1-z N layer; The n-Al y Ga 1-y N layer has a thickness of 200 to 1000 nm; The n-Al z Ga 1-z layer has a thickness of 0.1 to 100 nm; Among them, 0.7 ≤ y ≤ x ≤ z < 1.

5. The multi-wavelength light-emitting ultraviolet LED according to claim 1, wherein, The electron blocking layer is a P-AlGaN layer, and the P-AlGaN layer is a P-Al a Ga 1-a N layer, where 0.8 ≤ a < 1, and the thickness of the electron blocking layer is 0.5 to 50 nm.

6. The multi-wavelength light-emitting ultraviolet LED according to claim 1, wherein The P-type AlGaN layer is a P-Al b Ga 1- b GaN layer, 0.5 ≤ b < 1, and the thickness of the P-type AlGaN layer is 50 to 500 nm.

7. The multi-wavelength light-emitting ultraviolet LED according to claim 1, wherein The P-type ohmic contact layer is a P-type GaN layer with a thickness of 0.5-50 nm; The thickness of the AlN thin film layer is 50 nm to 500 nm.

8. A method for preparing a multi-wavelength light-emitting ultraviolet LED according to any one of claims 1 to 7, characterized in that, It includes the following steps: Grow an AlN template layer, an AlN thin film layer, an N-type intensity adjustment layer, an n-AlGaN layer, a quantum well light-emitting layer, an electron blocking layer, a P-type AlGaN layer, and a P-type ohmic contact layer on the substrate in sequence.

9. The preparation method of the multi-wavelength light-emitting ultraviolet LED according to claim 8, characterized in that, Grow an AlN template layer on the substrate and grow an AlN thin film layer on the AlN template layer; the growth temperature of the AlN thin film layer is 1100°C to 1300°C; An N-type intensity adjustment layer is grown on the AlN thin film layer, and the N-type intensity adjustment layer is n-Al x Ga 1-x N / n-AlN superlattice periodic structure layer, the growth temperature is 1000°C to 1200°C, and the carrier concentration is 5×10 17 ~1×10 19 cm -3 ; An n-AlGaN layer is grown on the N-type intensity adjustment layer, and the n-AlGaN layer includes successively stacked n-Al y Ga 1-y N layers, n-Al z Ga 1-z N layers, wherein the thickness of the n-Al y Ga 1-y N layer is 0.2 - 1 μm, the growth temperature is 1000 °C - 1200 °C, and the carrier concentration is 1×10 18 ~1×10 19 cm -3 ; n-Al z Ga 1-z The thickness of the N layer is 0.1 - 100 nm, the growth temperature is 1000 °C - 1200 °C, and the carrier concentration is 1×10 17 ~1×10 18 cm -3 ; Grow a quantum well light-emitting layer on the n-AlGaN layer; the quantum well light-emitting layer includes a long-wavelength quantum well light-emitting layer, a first short-wavelength quantum well light-emitting layer, and a second short-wavelength quantum well light-emitting layer that are sequentially stacked; among them, the long-wavelength quantum well light-emitting layer is an AlGaN / AlN quantum well light-emitting layer, the thickness of the AlGaN well layer is 1-10 nm, the thickness of the AlN barrier layer is 2-10 nm, and the number of quantum well periods of the long-wavelength quantum well light-emitting layer is 1-3; The first short-wavelength quantum well light-emitting layer includes an AlGaN / AlN / AlGaN well layer and an AlN barrier layer. The thickness of the AlN barrier layer is 2-10 nm, the thickness of the AlGaN / AlN / AlGaN well layer is 2-8 nm, and the thickness of the AlN layer in the well layer is 0.1-1 nm; the number of quantum well periods of the first short-wavelength quantum well light-emitting layer is 1-3; The second short-wavelength quantum well light-emitting layer includes an AlGaN / AlN / AlGaN well layer and an AlN barrier layer. The thickness of the AlN barrier layer is 1 to 6 nm, the thickness of the AlGaN / AlN / AlGaN well layer is 1 to 4 nm, and the thickness of the AlN layer in the well layer is 0.1 to 1.5 nm. The number of quantum well periods of the second short-wavelength quantum well light-emitting layer is 1 to 3; The growth temperature of the long-wavelength quantum well light-emitting layer is 1000 °C to 1100 °C, the growth temperature of the first short-wavelength quantum well light-emitting layer is 1100 °C to 1150 °C, and the growth temperature of the second short-wavelength quantum well light-emitting layer is 1150 °C to 1170 °C; An electron blocking layer is grown on the quantum well light-emitting layer, with a growth temperature of 1100 °C to 1200 °C and an Mg doping concentration of 1×10 18 ~1×10 19 cm -3 ; A P-type AlGaN layer is grown on the electron blocking layer at a growth temperature of 800°C to 1200°C, and the Mg doping concentration is 2×10 18 ~1×10 19 cm -3 .

10. The preparation method of the multi-wavelength light-emitting ultraviolet LED according to claim 8, characterized in that, A P-type ohmic contact layer is grown on the P-type AlGaN layer. The P-type ohmic contact layer is a P-type GaN layer, the growth temperature is 800 °C to 1100 °C, and the Mg doping concentration is 1×10 19 ~3×10 19 cm -3 ; Annealing is carried out under an inert atmosphere to obtain a multi-wavelength light-emitting ultraviolet LED.

Images