Multi-wavelength light-emitting diode and light-emitting module

Abstract

The present invention relates to the technical field of semiconductor devices, and particularly to a multi-wavelength light-emitting diode and a light-emitting module. In the multi-wavelength light-emitting diode, the multi-quantum well layer includes n groups of quantum well light-emitting units having different band gaps; the nth group of quantum well light-emitting units and the (n-1)th group of quantum well light-emitting units satisfy at least one of the following characteristics: (a) the concentration of In in at least one well layer of the nth group of quantum well light-emitting units is greater than the concentration of In in at least one well layer of the (n-1)th group of quantum well light-emitting units; (b) the thickness of at least one well layer of the nth group of quantum well light-emitting units is greater than the thickness of at least one well layer of the (n-1)th group of quantum well light-emitting units. By providing multiple groups of quantum well light-emitting units, the present invention can generate multiple wavelengths while taking into account the full release of stress and improving the photoelectric conversion efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and particularly to a multi-wavelength light-emitting diode and a light-emitting module. Background Art

[0002] A light-emitting diode (LED for short) can efficiently convert electrical energy into light energy. It is a light-emitting device that emits light by the recombination of electrons and holes, and is widely used in fields such as lighting and displays. In the prior art, in order to improve the color rendering index of white LEDs, blue light-emitting diodes with two wavelengths or multiple wavelengths are developed to excite phosphors to generate white light as a lighting source or a display source.

[0003] In the existing publicly disclosed white light-emitting module, there is a wide-band blue light-emitting chip and a wavelength conversion layer. The light-emitting stack of the wide-band blue light-emitting chip emits blue light of multiple wavelengths. At least one of the multiple quantum well layers close to the N-type semiconductor layer is a quantum well layer that can emit the longest wavelength, and the quantum well layer close to the P-type semiconductor layer is a quantum well layer that emits the shortest wavelength. Since multiple sets of light-emitting quantum wells are provided and the growth conditions of the well layers corresponding to different wavelengths vary greatly, this results in insufficient stress release of the epitaxial structure, and the light-emitting efficiency of such a multi-wavelength chip is significantly reduced compared with that of a single-wavelength chip. At the same time, in the white light spectrum generated by this method, the component of blue light is relatively high, and strong blue light, especially short blue light, is likely to cause damage to the human eye. Therefore, how to obtain a waveform closer to the standard light source in the blue light band on the premise of ensuring the photoelectric conversion efficiency of the LED chip to cooperate with the wavelength conversion material to generate a spectrum closer to natural light has important significance.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] An object of the present invention is to provide a multi-wavelength light-emitting diode, which can generate multiple wavelengths to help obtain a spectrum closer to natural light, while taking into account sufficient stress release and improving the photoelectric conversion efficiency.

[0006] Another object of the present invention is to provide a light-emitting module.

[0007] In order to achieve the above objects of the present invention, on the one hand, the present invention provides a multi-wavelength light-emitting diode, including:

[0008] a substrate, and an N-type semiconductor layer, a stress release layer, a multi-quantum well layer, and a P-type semiconductor layer sequentially disposed on the substrate; the multi-quantum well layer includes n groups of quantum well light-emitting units with different band gaps to respectively generate n groups of light with different wavelengths, where n≥3;

[0009] Define the direction from near the N-type semiconductor layer to near the P-type semiconductor layer as the first direction. Along the first direction, n groups of quantum well light-emitting units are respectively the 1st group, the 2nd group, …, the (n - 1)th group and the nth group of quantum well light-emitting units; each group of quantum well light-emitting units includes at least one well layer and one barrier layer. The nth group of quantum well light-emitting units and the (n - 1)th group of quantum well light-emitting units satisfy at least one of the following characteristics:

[0010] (a) The concentration of In in at least one well layer of the nth group of quantum well light-emitting units is greater than or equal to the concentration of In in at least one well layer of the (n - 1)th group of quantum well light-emitting units;

[0011] (b) The thickness of at least one well layer of the nth group of quantum well light-emitting units is greater than the thickness of at least one well layer of the (n - 1)th group of quantum well light-emitting units.

[0012] In a specific embodiment of the present invention, the wavelength of the light generated by the nth group of quantum well light-emitting units is greater than the wavelength of the light generated by the (n - 1)th group of quantum well light-emitting units.

[0013] In a specific embodiment of the present invention, the wavelength of the light generated by the 1st group of quantum well light-emitting units is greater than the wavelength of the light generated by the (n - 1)th group of quantum well light-emitting units.

[0014] In a specific embodiment of the present invention, for the 1st group, the 2nd group, …, the (n - 1)th group and the nth group of quantum well light-emitting units, the wavelengths of the generated light are λ1, λ2, …, λ n-1 、λ n respectively; each wavelength satisfies:

[0015] λ1 ≥ λ2 ≥ … ≥ λ n-1 ,λ n-1 ≤ λ n ≤ λ1. The light-emitting wavelength of the quantum well light-emitting unit (the (n - 1)th group of quantum well light-emitting units) second closest to the P-type semiconductor layer is the shortest.

[0016] In a specific embodiment of the present invention, the difference between the wavelengths of the light generated by adjacent groups of quantum well light-emitting units is ≤ 25 nm. Further, the wavelength of the light generated by the 1st group of quantum well light-emitting units is 450 - 475 nm; the wavelength of the light generated by the (n - 1)th group of quantum well light-emitting units is 430 - 450 nm; the wavelength of the light generated by the nth group of quantum well light-emitting units is 440 - 470 nm.

[0017] In a specific embodiment of the present invention, when the nth group of quantum well light-emitting units and the (n - 1)th group of quantum well light-emitting units satisfy characteristic (a), the concentrations of In in the single well layers of the 1st group, the 2nd group, …, the (n - 1)th group and the nth group of quantum well light-emitting units are c1, c2, …, c n-1, c n ; Each concentration satisfies c n ≥ c n-1 , c1 ≥ c2 ≥ … ≥ c n-1 . At the same time, define the thicknesses of the single well layers of the first group, the second group, …, the (n - 1)th group, and the nth group of quantum well light emitting units as h1, h2, …, h n-1 , h n ; Among them, h1 ≥ h2 ≥ … ≥ h n-1 , h n and h n-1 satisfy: h n > h n-1 or h n < h n-1 or h n = h n-1 .

[0018] In a specific embodiment of the present invention, when the nth group of quantum well light emitting units and the (n - 1)th group of quantum well light emitting units satisfy feature (b), the thicknesses of the single well layers of the first group, the second group, …, the (n - 1)th group, and the nth group of quantum well light emitting units are h1, h2, …, h n-1 , h n ; Each thickness satisfies: h n > h n-1 , h1 ≥ h2 ≥ … ≥ h n-1 . At the same time, define the concentrations of In in the well layers of the first group, the second group, …, the (n - 1)th group, and the nth group of quantum well light emitting units as c1, c2, …, c n-1 , c n ; Among them, c1 ≥ c2 ≥ … ≥ c n-1 , c n-1 and c n satisfy: c n > c n-1 or c n = c n-1 or c n < c n-1 .

[0019] Furthermore, the difference in the thickness of the single well layer of the nth group of quantum well light emitting units and the single well layer of the (n - 1)th group of quantum well light emitting units is 1 - 15 Å, preferably 2 - 10 Å.

[0020] In a specific embodiment of the present invention, the thicknesses of the barrier layers of the first group, the second group, …, the (n - 1)th group, and the nth group of quantum well light emitting units are t1, t2, …, t n-1 , t n ; Each thickness satisfies:

[0021] t n ≥ t n-1, t1≥t2≥…≥t n-1 .

[0022] In a specific embodiment of the present invention, one well layer and one barrier layer in the quantum well light-emitting unit are defined as one period, and the number of periodic structures of the first group, the second group, …, the (n - 1)th group, and the nth group of quantum well light-emitting units are X1, X2, …, X n-1 , X n respectively; the number of each periodic structure satisfies:

[0023] X n-1 > X1, X n-1 > X n , X n-1 > X2.

[0024] Another aspect of the present invention provides a light-emitting module, including any one of the above-mentioned light-emitting diodes and a wavelength conversion unit; the light generated by the light-emitting diode is mixed through the wavelength conversion unit to generate white light.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] (1) For the light-emitting diode of the present invention, by setting multiple groups of quantum well light-emitting units, multiple wavelengths are generated to obtain a light-emitting spectrum close to sunlight; at the same time, by adjusting the In content and / or well layer thickness in the quantum well light-emitting unit closest to the P-type semiconductor layer, the stress between the multiple quantum well layers and the P-type semiconductor layer is fully released, improving the light-emitting efficiency;

[0027] (2) The light-emitting diode of the present invention has a waveform in the blue light band closer to the standard light source, and after being combined with the wavelength conversion material, it can generate a spectrum closer to natural light. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 It is a schematic diagram of the epitaxial structure of the light-emitting diode provided by the embodiment of the present invention;

[0030] Figure 2 It is a schematic diagram of the structure of the multiple quantum well layer provided by the embodiment of the present invention;

[0031] Figure 3 It is a schematic diagram of the structure of the light-emitting diode provided by the embodiment of the present invention;

[0032] Figure 4 Schematic diagram of the bandgap structure of the multi-quantum well layer provided in Embodiment 1 of the present invention;

[0033] Figure 5 Schematic diagram of the bandgap structure of the multi-quantum well layer provided in Embodiment 2 of the present invention;

[0034] Figure 6 Schematic diagram of the bandgap structure of the multi-quantum well layer provided in Embodiment 3 of the present invention;

[0035] Figure 7 Schematic diagram of the bandgap structure of the multi-quantum well layer provided in Embodiment 4 of the present invention;

[0036] Figure 8 Schematic diagram of the bandgap structure of the multi-quantum well layer provided in Embodiment 5 of the present invention;

[0037] Figure 9 Schematic diagram of the bandgap structure of the multi-quantum well layer provided in Embodiment 6 of the present invention;

[0038] Figure 10 Spectral diagram generated by the light-emitting diode of Embodiment 6 of the present invention under different currents;

[0039] Figure 11 Comparison diagram of the luminous efficiency of the light-emitting diode of Embodiment 6 of the present invention and a traditional light-emitting diode at 60 mA.

[0040] Reference numerals:

[0041] 10 - Substrate; 20 - Buffer layer; 30 - N-type semiconductor layer; 40 - Stress relief layer; 50 - Multi-quantum well layer; 60 - P-type semiconductor layer; 51 - First group of quantum well light-emitting units; 52 - Second group of quantum well light-emitting units; 53 - (n - 1)th group of quantum well light-emitting units; 54 - nth group of quantum well light-emitting units; 510a - Well layer of the first group of quantum well light-emitting units; 510b - Barrier layer of the first group of quantum well light-emitting units; 520a - Well layer of the second group of quantum well light-emitting units; 520b - Barrier layer of the second group of quantum well light-emitting units; 530a - Well layer of the (n - 1)th group of quantum well light-emitting units; 530b - Barrier layer of the (n - 1)th group of quantum well light-emitting units; 540a - Well layer of the nth group of quantum well light-emitting units; 540b - Barrier layer of the nth group of quantum well light-emitting units; 511 - First well layer; 512 - First barrier layer; 521 - Second well layer; 522 - Second barrier layer; 531 - Third well layer; 532 - Third barrier layer; 541 - Fourth well layer; 542 - Fourth barrier layer; 551 - Fifth well layer; 552 - Fifth barrier layer. Detailed implementation manners

[0042] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be construed as limiting the scope of the present invention. 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. For those conditions not specified in the embodiments, they shall be carried out according to the conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not indicated by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0043] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and 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 therefore cannot be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0044] In the multi-wavelength LED technology, such as a dual-blue wavelength light-emitting device, the light-emitting quantum well structure first grows 2 to 3 periods of blue-green light quantum wells with an emission peak of 460 to 480 nm, and then grows 2 to 3 periods of blue-violet light quantum wells with an emission peak of 430 to 450 nm; then, by exciting a yellow phosphor to form a white LED, through the calculation of the color rendering index formula, the color rendering index of the white LED encapsulated by the dual-blue chip is significantly improved compared with that of the white LED formed by a single-blue chip. However, in the existing multi-wavelength LED technology, it is impossible to take into account both the photoelectric conversion efficiency of the LED chip and make the spectrum close to the natural light spectrum.

[0045] Based on this, on the one hand, the present invention provides a multi-wavelength light-emitting diode, Figure 1 which is a schematic diagram of the epitaxial structure of the light-emitting diode provided by the embodiment of the present invention. The epitaxial structure of the light-emitting diode includes:

[0046] a substrate 10, and a buffer layer 20, an N-type semiconductor layer 30, a stress release layer 40, a multi-quantum well layer 50, and a P-type semiconductor layer 60 sequentially disposed on the substrate 10. Among them, the multi-quantum well layer includes n groups of quantum well light-emitting units with different bandgaps to respectively generate n groups of lights with different wavelengths, n≥3, and n can be natural numbers such as 3, 4, 5, 6, etc., but is not limited thereto.

[0047] Figure 2It is a schematic structural diagram of a multi-quantum well layer provided by an embodiment of the present invention. In the multi-quantum well layer 50, the direction from near the N-type semiconductor layer 30 to near the P-type semiconductor layer 60 is defined as the first direction. Along the first direction, n groups of quantum well light-emitting units are respectively the 1st group of quantum well light-emitting units 51, the 2nd group of quantum well light-emitting units 52,..., the (n - 1)th group of quantum well light-emitting units 53, and the nth group of quantum well light-emitting units 54.

[0048] Among them, the nth group of quantum well light-emitting units 54 and the (n - 1)th group of quantum well light-emitting units 53 satisfy at least one of the following characteristics:

[0049] (a) The concentration of In in the well layer 540a of the nth group of quantum well light-emitting units is greater than or equal to the concentration of In in the well layer 530a of the (n - 1)th group of quantum well light-emitting units;

[0050] (b) The thickness of the well layer 540a of the nth group of quantum well light-emitting units is greater than the thickness of the well layer 530a of the (n - 1)th group of quantum well light-emitting units.

[0051] When the light-emitting diode satisfies one or two of (a) and (b), the nth group of quantum well light-emitting units 54 can fully release the stress between the multi-quantum well layer 50 and the P-type semiconductor layer 60, and achieve the effect of supplementing the relatively weak light-emitting intensity of the 1st group of quantum well light-emitting units 51. At the same time, fully releasing the stress can significantly improve the light-emitting efficiency of the device.

[0052] The multi-wavelength light-emitting diode of the present invention can only satisfy (a), only satisfy (b), or satisfy (a) and (b) simultaneously. When satisfying (a), the thickness of the well layer of each quantum well light-emitting unit can be set conventionally. The well layer 540a of the nth group of quantum well light-emitting units has an In concentration higher than or equal to that of the well layer 530a of the (n - 1)th group of quantum well light-emitting units, changing the distribution of carriers in the entire multi-quantum well layer 50, making the carrier distribution closer to the P-type semiconductor layer 60, which helps to improve the brightness. In addition, the wavelength of the light generated by the nth group of quantum well light-emitting units 54 is close to the wavelength of the light generated by the 1st group of quantum well light-emitting units 51, which can enhance the light-emitting brightness of the 1st group of quantum well light-emitting units 51. When satisfying (b), the concentration of In in the well layer of the quantum well light-emitting unit can be set conventionally. The well layer 540a of the nth group of quantum well light-emitting units has a thickness greater than that of the well layer 530a of the (n - 1)th group of quantum well light-emitting units. The energy barrier of the well layer 540a of the nth group of quantum well light-emitting units is lower, which can pull the energy band of the entire light-emitting region, change the distribution of carriers in the entire multi-quantum well layer 50, and make the carrier distribution closer to the P-type semiconductor layer 60, which helps to improve the brightness.

[0053] In an embodiment of the present invention, as an optional embodiment, the wavelength of the light generated by the nth group of quantum well light-emitting units 54 is greater than the wavelength of the light generated by the (n - 1)th group of quantum well light-emitting units 53. In actual operation, the first group of quantum well light-emitting units 51 and the nth group of quantum well light-emitting units 54 are grown under the same conditions. Since the nth group of quantum well light-emitting units 54 is closer to the P-type semiconductor layer 60, at a small current, its electron-hole recombination efficiency is higher, and the nth group of quantum well light-emitting units 54 can enhance the intensity of the light generated by the first group of quantum well light-emitting units 51.

[0054] In an embodiment of the present invention, as an optional embodiment, the wavelength of the light generated by the first group of quantum well light-emitting units 51, which is closer to the N-type semiconductor layer, is greater than the wavelength of the light generated by the (n - 1)th group of quantum well light-emitting units 53.

[0055] Figure 2 FIG. 7 is a schematic structural diagram of a multi-quantum well layer provided by an embodiment of the present invention. Along a first direction, the multi-quantum well layer 50 includes the first group of quantum well light-emitting units 51, the second group of quantum well light-emitting units 52,..., the (n - 1)th group of quantum well light-emitting units 53, and the nth group of quantum well light-emitting units 54. Each group of quantum well light-emitting units includes at least one periodically structured well layer and barrier layer stacked alternately. For example, the first group of quantum well light-emitting units 51 includes the well layer 510a of the first group of quantum well light-emitting units and the barrier layer 510b of the first group of quantum well light-emitting units stacked alternately, the second group of quantum well light-emitting units 52 includes the well layer 520a of the second group of quantum well light-emitting units and the barrier layer 520b of the second group of quantum well light-emitting units stacked alternately, the (n - 1)th group of quantum well light-emitting units 53 includes the well layer 530a of the (n - 1)th group of quantum well light-emitting units and the barrier layer 530b of the (n - 1)th group of quantum well light-emitting units stacked alternately, and the nth group of quantum well light-emitting units 54 includes the well layer 540a of the nth group of quantum well light-emitting units and the barrier layer 540b of the nth group of quantum well light-emitting units stacked alternately.

[0056] In an embodiment of the present invention, as an optional embodiment, for the first group, the second group,..., the (n - 1)th group, and the nth group of quantum well light-emitting units along the first direction, the wavelengths of the light generated are λ1, λ2,..., λ n-1 , λ n ; each wavelength satisfies: λ1 ≥ λ2 ≥... ≥ λ n-1 , λ n-1 ≤ λ n ≤ λ1. The light-emitting wavelength of the quantum well light-emitting unit that is second closest to the P-type semiconductor layer 60 is the shortest.

[0057] In an embodiment of the present invention, as an optional embodiment, the difference in the wavelengths of the light generated by adjacent groups of quantum well light-emitting units is ≤ 25 nm. For example, the difference can be 25 nm, 22 nm, 20 nm, 18 nm, 15 nm, 10 nm, 5 nm, 2 nm, or any range composed of any two of them.

[0058] In an embodiment of the present invention, as an optional embodiment, the wavelength of the light generated by the first group of quantum well light-emitting units 51 is 450 - 475 nm; the wavelength of the light generated by the (n - 1)th group of quantum well light-emitting units 53 is 430 - 450 nm; the wavelength of the light generated by the nth group of quantum well light-emitting units 54 is 440 - 470 nm.

[0059] For example, in an optional embodiment, when the multiple quantum well layer includes 3 groups of quantum well light-emitting units with different bandgaps, the wavelengths of the light generated by the first group, the second group, and the third group of quantum well light-emitting units are 450 - 475 nm, 430 - 450 nm, and 440 - 470 nm respectively. In another optional embodiment, when the multiple quantum well layer includes 4 groups of quantum well light-emitting units with different bandgaps, the wavelengths of the light generated by the first group, the second group, the third group, and the fourth group of quantum well light-emitting units are 460 - 475 nm, 445 - 460 nm, 435 - 445 nm, and 455 - 465 nm respectively. The specific wavelengths of the light generated by each quantum well light-emitting unit can be adaptively adjusted according to the desired spectral shape.

[0060] In an embodiment of the present invention, as an optional embodiment, the emission wavelength of each group of quantum well light-emitting units is adjusted by controlling at least one of the In concentration in the well layer, the thickness of the well layer, and the thickness of the barrier layer in each group of quantum well light-emitting units, so that the wavelengths generated by each group of quantum well light-emitting units meet the above conditions.

[0061] To achieve that the wavelength λ n of the nth group of quantum well light-emitting units is greater than the wavelength λ n-1 of the (n - 1)th group of quantum well light-emitting units, in an embodiment of the present invention, it can be achieved by setting the thickness of a single well layer of the nth group of quantum well light-emitting units to be greater than the thickness of a single well layer of the (n - 1)th group of quantum well light-emitting units, or setting the In concentration of a single well layer of the nth group of quantum well light-emitting units to be greater than or equal to the In concentration of a single well layer of the (n - 1)th group of quantum well light-emitting units.

[0062] In an embodiment of the present invention, as an optional embodiment, the thicknesses of the single barrier layers of each group of quantum well light-emitting units are t1, t2,..., t n-1 , t n respectively; each thickness satisfies: t n ≥ t1, t1 ≥ t2 ≥... ≥ t n-1 .

[0063] In an embodiment of the present invention, as an alternative embodiment, one well layer and one barrier layer in the quantum well light-emitting unit are defined as one period, and the number of periodic structures in the (n - 1)th group of quantum well light-emitting units 53 is greater than the number of periodic structures in the first group of quantum well light-emitting units 51. Further, the number of periodic structures in the first group of quantum well light-emitting units 51 is greater than or equal to the number of periodic structures in the nth group of quantum well light-emitting units 54.

[0064] In an embodiment of the present invention, as an alternative embodiment, for the first group, the second group, …, the (n - 1)th group, and the nth group of quantum well light-emitting units among the n groups of quantum well light-emitting units along the first direction, the number of periodic structures in each group of quantum well light-emitting units is X1, X2, …, X n-1 、X n ; The number of each periodic structure satisfies:

[0065] X n-1 >X1, X n-1 >X n ,X n-1 >X2.

[0066] In an embodiment of the present invention, as an alternative embodiment, the well layer / barrier layer periodic structure is an InGaN well layer / GaN-based barrier layer. Further, in the well layer of each group of quantum well light-emitting units, the concentration of In > 3×10 20 Atoms / cm 3 .

[0067] In an embodiment of the present invention, as an alternative embodiment, the nth group of quantum well light-emitting units 54 includes at least two well layers with different In concentrations. Further, the In concentration of at least one well layer in the nth group of quantum well light-emitting units 54 is greater than or equal to the In concentration in the well layer 530a of the (n - 1)th group of quantum well light-emitting units. Further still, as an alternative embodiment, along the direction from the (n - 1)th group of quantum well light-emitting units 53 to the P-type semiconductor layer 60 in the nth group of quantum well light-emitting units 54, the In concentration in the well layer increases or remains unchanged. Among them, the increase can be in a regular gradient, randomly, monotonically, or fluctuatingly, and is not limited thereto.

[0068] In an embodiment of the present invention, as an alternative embodiment, the thickness of the multiple quantum well layer 50 is 110 - 170 nm. Further, the thickness of the well layer / barrier layer periodic structure is 10 - 19 nm; the well layer / barrier layer periodic structure is InGaN / GaN. Further, the thickness of InGaN is 1 - 4 nm, and the thickness of GaN is 9 - 15 nm.

[0069] In an embodiment of the present invention, as an optional embodiment, the stress release layer 40 includes an InGaN / GaN superlattice layer. Further, in the stress release layer 40, the concentration of In < 3×10 20 Atoms / cm 3 , preferably the concentration of In > 4×10 19 Atoms / cm 3 .

[0070] In an embodiment of the present invention, as an optional embodiment, the stress release layer 40 is doped with Si and / or Al.

[0071] In an embodiment of the present invention, as an optional embodiment, the P-type semiconductor layer 60 includes a P-type AlGaN electron blocking layer and a Mg-doped P-type GaN layer. Among them, in the Mg-doped P-type GaN layer, the average doping concentration of Mg is 1×10 19 ~1×10 21 Atoms / cm 3 .

[0072] In an embodiment of the present invention, as an optional embodiment, the N-type semiconductor layer 30 includes an undoped GaN layer and an Si-doped N-type GaN layer. Among them, the thickness of the undoped GaN layer can be 1.5 - 2.5 μm, and the thickness of the Si-doped N-type GaN layer can be 1.5 - 2.5 μm; in the Si-doped N-type GaN layer, the doping concentration of Si can be 1×10 19 ~1×10 20 Atoms / cm 3 .

[0073] The light-emitting diode formed by the above epitaxial structure can be fabricated into a front-side structure LED chip, a flip-chip LED structure chip, a vertical structure LED chip, a Mini LED, and a Micro LED according to actual application requirements, which are not limited herein. For demonstration, Figure 3 a schematic diagram of a front-side LED chip structure is shown, including any one of the above multi-wavelength light-emitting diode epitaxial structures.

[0074] Further, the light-emitting diode further includes a current blocking layer, a current spreading layer, an N electrode, a P electrode, and an insulating layer;

[0075] The current blocking layer is disposed on the P-type semiconductor layer 60; the current spreading layer is stacked on the P-type semiconductor layer 60 and the current blocking layer; the P electrode is disposed on the current spreading layer and electrically connected to the P-type semiconductor layer 60; the N electrode is disposed in the N step region and electrically connected to the N-type semiconductor layer 30; the insulating layer covers the P electrode and the N electrode and exposes a part of the P electrode and the N electrode to form an opening.

[0076] In another aspect of the present invention, there is provided a light-emitting module, which includes any one of the above-mentioned light-emitting diodes and a wavelength conversion unit; the light generated by the light-emitting diode is mixed through the wavelength conversion unit to generate white light.

[0077] Based on this, embodiments of the present invention provide multi-wavelength light-emitting diodes and light-emitting modules, which will be described below through embodiments.

[0078] Embodiment 1

[0079] Figure 4 FIG. 10 is a schematic diagram of the bandgap structure of the multi-quantum well layer provided in Embodiment 1 of the present invention. The multi-quantum well layer 50 in this embodiment includes 3 groups of quantum well light-emitting units with different bandgap widths, namely the first group of quantum well light-emitting units, the second group of quantum well light-emitting units, and the third group of quantum well light-emitting units, to generate 3 groups of lights with different wavelengths respectively. The bandgap widths of the well layers of the 3 groups of quantum well light-emitting units are Eg1, Eg2, and Eg3 respectively.

[0080] Among them, the first group of quantum well light-emitting units is closest to the N-type semiconductor layer and includes a periodic structure of alternately stacked first well layers 511 and first barrier layers 512; the third group of quantum well light-emitting units is closest to the P-type semiconductor layer and includes a third well layer 531 and a third barrier layer 532; the second group of quantum well light-emitting units is arranged between the first group of quantum well light-emitting units and the second group of quantum well light-emitting units and includes a periodic structure of alternately stacked second well layers 521 and second barrier layers 522. Among them, the well layer is an InGaN material layer with different In concentrations, and the barrier layer is a GaN-based material layer. The In concentration in the third well layer 531 is greater than the In concentration in the second well layer 521. The In concentration in the first well layer 511 is greater than the In concentration in the third well layer 531. The emission wavelength λ1 of the first group of quantum well light-emitting units is the longest, and the emission wavelength λ2 of the second group of quantum well light-emitting units is the shortest. Further, to adjust the emission wavelength λ1 of the first group of quantum well light-emitting units, in addition to setting a relatively large In concentration, the thickness of the first well layer 511 can also be set to be greater than that of the second well layer 521. The emission wavelength of the light-emitting unit can be adjusted by adjusting one or more of the In concentration, well layer thickness, barrier layer thickness, number of periods, etc.

[0081] In a possible embodiment, the number of periods X1 of the first group of quantum well light-emitting units is less than the number of periods X2 of the second group of quantum well light-emitting units but greater than the number of periods X3 of the third group of quantum well light-emitting units. For example, X1 is 3, X2 is 6, and X3 is 1.

[0082] The first well layer 511, the second well layer 521, and the third well layer 531 have substantially the same thickness, and the thickness range is 30 - 40 Å. The first barrier layer 512, the second barrier layer 522, and the third barrier layer 532 also have substantially the same thickness, and the thickness range is 90 - 150 Å. The In concentration in the InGaN first well layer 511 > 3×10 20 Atoms / cm 3 , for example, it can be 7×10 20 - 8×10 20 Atoms / cm 3 ; the In concentration range in the second well layer 521 is 4.5×10 20 - 5×10 20 Atoms / cm 3 ; the In concentration range in the third well layer 531 is 5×10 20 - 6×10 20 Atoms / cm 3 ; a multi-wavelength blue light emitting diode formed with at least 3 peak wavelengths in the range of 430 - 475 nm.

[0083] Example 2

[0084] Figure 5 The schematic diagram of the bandgap structure of the multi-quantum well layer provided by Example 2 of the present invention. The multi-quantum well layer 50 of this example includes 4 groups of quantum well light emitting units with different bandgaps, namely the first group of quantum well light emitting units, the second group of quantum well light emitting units, the third group of quantum well light emitting units, and the fourth group of quantum well light emitting units, to generate 4 groups of light beams with different wavelengths respectively. The bandgaps of the well layers of the 4 groups of quantum well light emitting units are Eg1, Eg2, Eg3, and Eg4 respectively.

[0085] Specifically, the first group of quantum well light emitting units is closest to the N-type semiconductor layer, and includes a periodic structure of a first well layer 511 and a first barrier layer 512 stacked, with the number of periods being X1; the fourth group of quantum well light emitting units is closest to the P-type semiconductor layer, and includes a periodic structure of a fourth well layer 541 and a fourth barrier layer 542 stacked, with the number of periods being X4; the second group of quantum well light emitting units is arranged between the first group of quantum well light emitting units and the fourth group of quantum well light emitting units, and includes a periodic structure formed by alternately stacking a second well layer 521 and a second barrier layer 522, with the number of periods being X2; the third group of quantum well light emitting units is arranged between the second group of quantum well light emitting units and the fourth group of quantum well light emitting units and is closest to the fourth group of quantum well light emitting units, and includes a periodic structure formed by alternately stacking a third well layer 531 and a third barrier layer 532, with the number of periods being X3. Among them, X3 ≥ X2 > X1 ≥ X4. In a possible embodiment, X1 = X4 = 1, X3 = 6, and X2 = 2.

[0086] The first well layer 511, the second well layer 521, the third well layer 531, and the fourth well layer 541 are all InGaN material layers. Their In concentration distributions are C1, C2, C3, and C4, and their thicknesses are h1, h2, h3, and h4 respectively. Among them, C1 > C2 > C3, C4 > C3, and C1 > C4. The relationship between C4 and C2 can be C2 ≥ C4 or C2 ≤ C4. The fourth well layer 541 is mainly used to supplement the emission spectra of the first well layer 511, the second well layer 521, and the third well layer 531 to realize a full-spectrum light-emitting diode.

[0087] The thicknesses h2, h3, and h4 of the well layers are basically the same. In a specific embodiment, h1 can be greater than h2 or equal to h2. The beam wavelength emitted by the first well layer 511 is the largest, and the beam wavelength emitted by the third well layer 531 is the shortest. A multi-wavelength blue light-emitting diode with at least 3 peak wavelengths in the range of 430 - 475 nm is formed.

[0088] Furthermore, the wavelengths of the light generated by the first group of quantum well light-emitting units, the second group of quantum well light-emitting units, the third group of quantum well light-emitting units, and the fourth group of quantum well light-emitting units can be 458 - 475 nm, 445 - 458 nm, 435 - 450 nm, and 445 - 460 nm respectively.

[0089] Embodiment 3

[0090] Figure 6 This is a schematic diagram of the bandgap structure of the multi-quantum well layer provided in Embodiment 3 of the present invention. The multi-quantum well layer 50 of this embodiment refers to Embodiment 2, with the difference being that the number of periods of each multi-quantum well light-emitting unit is different. Among them, the number of periods X3 of the third multi-quantum well light-emitting unit is greater than the number of periods X2 of the second multi-quantum well light-emitting unit, which is greater than the number of periods X1 of the first multi-quantum well light-emitting unit, which is greater than the number of periods X4 of the fourth multi-quantum well light-emitting unit, that is, X3 > X2 > X1 > X4. In a specific implementation, X3 is 4, X2 is 3, X1 is 2, and X4 is 1. A multi-wavelength blue light-emitting diode with at least 3 peak wavelengths in the range of 430 - 475 nm is formed.

[0091] Embodiment 4

[0092] Figure 7 This is a schematic diagram of the bandgap structure of the multi-quantum well layer provided in Embodiment 4 of the present invention. The multi-quantum well layer 50 of this embodiment includes 4 groups of quantum well light-emitting units with different bandgaps, namely the first group of quantum well light-emitting units, the second group of quantum well light-emitting units, the third group of quantum well light-emitting units, and the fourth group of quantum well light-emitting units, to generate 4 groups of light with different wavelengths respectively. The bandgaps of the well layers of the 4 groups of quantum well light-emitting units are Eg1, Eg2, Eg3, and Eg4’ / Eg4’’ respectively.

[0093] Among them, the first group of quantum well light-emitting units includes a periodic structure of alternately stacked first well layer 511 and first barrier layer 512, the second group of quantum well light-emitting units includes a periodic structure of alternately stacked second well layer 521 and second barrier layer 522, the third group of quantum well light-emitting units includes a periodic structure of alternately stacked third well layer 531 and third barrier layer 532, and the fourth group of quantum well light-emitting units includes at least one group of first periodic structure and second periodic structure alternately stacked. Among them, the first periodic structure is a periodic structure of fourth well layer 541 and fourth barrier layer 542, and the second periodic structure is a periodic structure of fifth well layer 551 and fifth barrier layer 552. The fourth well layer 541 and the fifth well layer 551 have different In concentrations. The In concentrations in the fourth well layer 541 and the fifth well layer 551 are greater than the In concentration in the third well layer 531.

[0094] Furthermore, the wavelengths of the light generated by the first group of quantum well light-emitting units, the second group of quantum well light-emitting units, the third group of quantum well light-emitting units, and the fourth group of quantum well light-emitting units can be 458 - 475 nm, 445 - 458 nm, 435 - 450 nm, and 445 - 460 nm respectively.

[0095] Embodiment 5

[0096] Figure 8 It is a schematic diagram of the bandgap structure of the multiple quantum well layers provided in Embodiment 5 of the present invention. The difference between this embodiment and Embodiment 1 is that: the thickness h3 of the third well layer 531 is greater than the thickness h2 of the second well layer 521. The In concentration C3 of the third well layer 531 is basically the same as the In concentration C2 of the second well layer 521, and the In concentration C1 of the first well layer 511 is the highest. The thickness h1 of the first well layer 511 is greater than the thickness h2 of the second well layer 521.

[0097] In a possible implementation manner, the In concentration in the first well layer 511 > 3×10 20 Atoms / cm 3 , such as it can be 6.8×10 20 Atoms / cm 3 ; the thickness of the first well layer 511 is 37 Å, and the thickness of the first barrier layer 512 is 120 Å.

[0098] Furthermore, the In concentration in the second well layer 521 > 3×10 20 Atoms / cm 3 , such as it can be 5×10 20 Atoms / cm 3 ; the thickness of the second well layer 521 is 33 Å, and the thickness of the second barrier layer 522 is 100 Å.

[0099] Furthermore, the In concentration in the third well layer 531 > 3×1020 Atoms / cm 3 , such as it can be 5×10 20 Atoms / cm 3 ; The thickness of the third well layer 531 is 37 Å, and the thickness of the third barrier layer 532 is 142 Å.

[0100] Furthermore, the wavelengths of the light generated by the first group of quantum well light emitting units, the second group of quantum well light emitting units, and the third group of quantum well light emitting units can be 450 - 470 nm, 435 - 450 nm, and 445 - 465 nm respectively.

[0101] Embodiment 6

[0102] Figure 9 It is a schematic diagram of the bandgap structure of the multi - quantum well layer provided in Embodiment 6 of the present invention. The multi - quantum well layer 50 of this embodiment includes 4 groups of quantum well light emitting units with different bandgaps, namely the first group of quantum well light emitting units, the second group of quantum well light emitting units, the third group of quantum well light emitting units, and the fourth group of quantum well light emitting units, to generate 4 groups of light with different wavelengths respectively. The bandgaps of the well layers of the 4 groups of quantum well light emitting units are Eg1, Eg2, Eg3, and Eg4 respectively.

[0103] Among them, the first group of quantum well light emitting units includes a periodic structure of alternately stacked first well layer 511 and first barrier layer 512, the second group of quantum well light emitting units includes a periodic structure of alternately stacked second well layer 521 and second barrier layer 522, the third group of quantum well light emitting units includes a periodic structure of alternately stacked third well layer 531 and third barrier layer 532, and the fourth group of quantum well light emitting units includes a periodic structure of alternately stacked fourth well layer 541 and fourth barrier layer 542. The thickness h4 of the fourth well layer 541 is greater than the thickness h3 of the third well layer 531.

[0104] Furthermore, the thickness h1 of the first well layer 511 is less than the thickness h4 of the fourth well layer 541, and the thickness h1 of the first well layer 511 is less than or equal to the thickness h2 of the second well layer 521.

[0105] Furthermore, the thickness h2 of the second well layer 521 is less than or equal to the thickness h3 of the third well layer 531.

[0106] Furthermore, the thickness of the fourth barrier layer 542 is greater than the thickness of the first barrier layer 512.

[0107] Furthermore, the concentration of In in each well layer satisfies: the first well layer 511 > the second well layer 521 ≥ the third well layer 531 ≥ the fourth well layer 541.

[0108] Further, in the first group of quantum well light-emitting units, the number of periods of the first well layer 511 / first barrier layer 512 periodic structure ≥ 1, such as it can be 1; the In concentration in the first well layer 511 > 3×10 20 Atoms / cm 3 , such as it can be 7.8×10 20 Atoms / cm 3 ; the thickness h1 of the first well layer 511 is 31 Å, and the thickness of the first barrier layer 512 is 120 Å.

[0109] Further, in the second group of quantum well light-emitting units, the number of periods of the second well layer 521 / second barrier layer 522 periodic structure ≥ 1, such as it can be 2; the In concentration in the second well layer 521 > 3×10 20 Atoms / cm 3 , such as it can be 6.8×10 20 Atoms / cm 3 ; the thickness h2 of the second well layer 521 is 33 Å, and the thickness of the second barrier layer 522 is 100 Å.

[0110] Further, in the third group of quantum well light-emitting units, the number of periods of the third well layer 531 / third barrier layer 532 periodic structure ≥ 3, such as it can be 6; the In concentration in the third well layer 531 > 3×10 20 Atoms / cm 3 , such as it can be 5×10 20 Atoms / cm 3 ; the thickness h3 of the third well layer 531 is 33 Å, and the thickness of the third barrier layer 532 is 100 Å.

[0111] Further, in the fourth group of quantum well light-emitting units, the number of periods of the fourth well layer 541 / fourth barrier layer 542 periodic structure ≥ 1, such as it can be 1; the In concentration in the fourth well layer 541 > 3×10 20 Atoms / cm 3 , such as it can be 5×10 20 Atoms / cm 3 ; the thickness h4 of the fourth well layer 541 is 37 Å, and the thickness of the fourth barrier layer 542 is 142 Å.

[0112] Further, the wavelengths of the light generated by the first group of quantum well light-emitting units, the second group of quantum well light-emitting units, the third group of quantum well light-emitting units, and the fourth group of quantum well light-emitting units are λ1, λ2, λ3, and λ4 respectively, where λ1 > λ2 > λ3 and λ4 > λ3. The peak wavelength emitted by the third group of quantum well light-emitting units is the shortest. Among them, the range of λ1 is: 458 - 475 nm, the range of λ2 is: 446 - 458 nm, the range of λ3 is: 435 - 446 nm, and the range of λ4 is: 443 - 463 nm, forming a light-emitting diode with at least 4 relatively distinct peak wavelengths.

[0113] In a modified embodiment, the thickness h1 of the first well layer 511 is the same as or slightly greater than the thickness h2 of the second well layer 521. Moreover, the thickness h1 of the first well layer 511 is close to the thickness h4 of the fourth well layer 541.

[0114] In another modified embodiment, in addition to the thickness h4 of the fourth well layer 541 being greater than the thickness h3 of the third well layer 531, the In concentration of the fourth well layer 541 is also greater than the In concentration of the third well layer 531, enhancing the intensity augmentation effect of the 4th multi-quantum well light-emitting unit in the relatively long-wavelength band spectrum.

[0115] In yet another modified embodiment, the material of at least one of the first barrier layer 512, the second barrier layer 522, the third barrier layer 532, and the fourth barrier layer 542 contains AlGaN or AlN. Preferably, the fourth barrier layer 542 closest to the P-type semiconductor layer contains a GaN layer and an AlGaN layer, and moreover, an InAlGaN layer.

[0116] In the modified embodiment, the number and number of periods of each multi-quantum well light-emitting unit are not limited to the examples in the above embodiments, but generally follow that the number of periods of the multi-quantum well light-emitting unit emitting the shortest wavelength is the largest, while the number of periods of the multi-quantum well light-emitting unit emitting a long wavelength will decrease. In order to fit a light-emitting diode with a full spectrum closer to sunlight, it may further include the 5th, 6th, 7th, etc. groups of multi-quantum well light-emitting units, but the emission wavelength of the group of multi-quantum well light-emitting units closest to the P-type semiconductor layer should be longer than that of the multi-quantum well light-emitting unit next closest to the P-type semiconductor layer. This is mainly because the last group of multi-quantum well light-emitting units is to supplement the spectrum of the multi-quantum well light-emitting units on the N-type layer side, and fit the full spectrum within a certain wavelength range as much as possible.

[0117] Figure 10 This is the spectral diagram of the light beam generated by the light-emitting diode of Embodiment 6 of the present invention under different currents. Figure 11 For the comparison of the luminous efficiency of the light-emitting diode based on Embodiment 6 of the present invention and the traditional light-emitting diode at 60 mA, from Figure 11It can be seen that the luminous efficiency of the light-emitting diode of the present invention at 60 mA is increased by 1.4% compared with that of the traditional light-emitting diode.

[0118] As can be seen from the above, the multi-wavelength light-emitting diode of the present invention generates multiple wavelengths through the arrangement of multiple groups of quantum well light-emitting units to obtain a light-emitting spectrum close to sunlight; at the same time, by adjusting the In content and / or well layer thickness in the quantum well light-emitting unit closest to the P-type semiconductor layer, the stress between the multi-quantum well layer and the P-type semiconductor layer is fully released, achieving the effect of improving the luminous efficiency.

[0119] An embodiment of the present invention also provides a method for manufacturing a multi-wavelength light-emitting diode, including the following steps:

[0120] On the substrate 10, the first half of the buffer layer 20 is grown for 1 minute. The purpose is to compensate for lattice mismatch and form nucleation islands. The temperature of this layer is controlled at 800 °C and the pressure is 150 torr. Then, the second half of the buffer layer 20 is grown for 10 - 25 minutes. During this process, the temperature is controlled at 1120 °C and the pressure is 200 torr. The purpose is to grow GaN with high crystal quality and low defect density.

[0121] The N-type semiconductor layer 30 is continuously grown on the buffer layer 20 to provide electrons. Among them, Si is doped in the N-type semiconductor layer 30 to provide electrons. The temperature is controlled at 1050 °C and the pressure is 200 torr; among them, the doping concentration of silicon is 1e+19 - 2e+20 Atoms / cm 3 。

[0122] The stress release layer 40 is continuously grown on the N-type semiconductor layer 30 to release the compressive stress generated by the lattice mismatch between the subsequently grown InGaN quantum well and the GaN of the N-type semiconductor layer 30. Its temperature is controlled at 800 - 900 °C and the pressure is 200 torr. Among them, this layer can be a single-layer or multi-layer structure, and elements such as Si / Al / In can be doped. The doping concentration of silicon is 1e+17 Atoms / cm 3 ~5e+18 Atoms / cm 3 and the indium doping concentration is 0 - 1e+20 Atoms / cm 3 。

[0123] The multi-quantum well layer 50 is continuously grown on the stress release layer 40. This layer forms multi-quantum well radiative emission through the recombination of electrons and holes. The temperature of this layer is controlled at 700 - 800 °C and the pressure is 200 tor.

[0124] Continuously grow a P-type semiconductor layer 60 on the multi-quantum well layer 50, and the function of this layer is to provide holes for the device. The temperature of this layer is controlled at 700 - 1000 °C, and the pressure is 1000 tor.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-wavelength light emitting diode, characterized in that, Comprising at least: An N-type semiconductor layer, and a stress release layer, a multiple quantum well layer, and a P-type semiconductor layer sequentially disposed on the N-type semiconductor layer; the multiple quantum well layer includes n groups of quantum well light-emitting units with different band gaps to respectively generate n groups of light with different wavelengths, where n≥3; Define the direction from near the N-type semiconductor layer to near the P-type semiconductor layer as the first direction. Along the first direction, n groups of quantum well light-emitting units are respectively the 1st group, the 2nd group, …, the (n - 1)th group, and the nth group of quantum well light-emitting units; the In concentrations in the single well layers of the 1st group, the 2nd group, …, the (n - 1)th group, and the nth group of quantum well light-emitting units are c1, c2, …, c n-1 , c n , and satisfy: c1 > c n-1 ; The multi-wavelength light-emitting diode is a multi-wavelength light-emitting diode having at least 3 peak wavelengths in the range of 430 - 475 nm; Each group of quantum well light-emitting units includes at least one well layer and one barrier layer, and the nth group of quantum well light-emitting units and the (n - 1)th group of quantum well light-emitting units satisfy the following characteristics: (a) The concentration of In in at least one well layer of the nth group of quantum well light-emitting units is greater than the concentration of In in at least one well layer of the (n - 1)th group of quantum well light-emitting units; (b) The thickness of at least one well layer of the nth group of quantum well light-emitting units is greater than the thickness of at least one well layer of the (n - 1)th group of quantum well light-emitting units.

2. The multi-wavelength light-emitting diode according to claim 1, characterized in that, The wavelength of the light generated by the nth group of quantum well light-emitting units is greater than the wavelength of the light generated by the (n - 1)th group of quantum well light-emitting units; And / or, the wavelength of the light generated by the first group of quantum well light-emitting units is greater than the wavelength of the light generated by the (n - 1)th group of quantum well light-emitting units.

3. The multi-wavelength light emitting diode according to claim 1, wherein The first group, the second group, …, the (n - 1)th group, and the nth group of quantum well light emitting units generate light with wavelengths of λ1, λ2, …, λ n-1 , λ n respectively; each wavelength satisfies: λ1 ≥ λ2 ≥ … ≥ λ n-1 , λ n-1 ≤ λ n ≤ λ1.

4. The multi-wavelength light emitting diode according to claim 3, characterized in that, The difference Δλ between the wavelengths of the light generated by adjacent groups of quantum well light-emitting units is ≤25 nm; The wavelength of the light generated by the first group of quantum well light-emitting units is 450 - 475 nm; the wavelength of the light generated by the (n - 1)th group of quantum well light-emitting units is 430 - 450 nm; the wavelength of the light generated by the nth group of quantum well light-emitting units is 440 - 470 nm.

5. The multi-wavelength light-emitting diode according to claim 1, wherein, The In concentrations in the single well layer of the first group, the second group, …, the (n - 1)-th group, and the n-th group of quantum well light-emitting units are c1, c2, …, c n-1 , c n , respectively, and each concentration satisfies: c n ≥c n-1 , c1 ≥ c2 ≥ … ≥ c n-1 .

6. The multi-wavelength light-emitting diode according to claim 5, wherein, The thicknesses of the single well layers of the first group, the second group, …, the (n - 1)th group, and the nth group of quantum well light-emitting units are h1, h2, …, h n-1 , h n ; where h1 ≥ h2 ≥ … ≥ h n-1 , h n and h n-1 satisfy: h n > h n-1 or h n < h n-1 or h n = h n-1 .

7. The multi-wavelength light-emitting diode according to claim 1, wherein The thicknesses of the single well layers of the first, second, …, (n - 1)-th, and n-th quantum well light-emitting units are h1, h2, …, h n-1 , h n ; each thickness satisfies: h n > h n-1 , h1 ≥ h2 ≥ … ≥ h n-1 .

8. The multi-wavelength light emitting diode according to claim 7, wherein, The thickness difference between a single well layer of the nth group of quantum well light-emitting units and a single well layer of the (n - 1)th group of quantum well light-emitting units is 1 - 15 Å.

9. The multi-wavelength light-emitting diode according to claim 7, wherein The concentrations of In in the single well layer of the first group, the second group, …, the (n - 1)-th group and the n-th group of quantum well light-emitting units are c1, c2, …, c n-1 , c n ; Among them, c1 ≥ c2 ≥ … ≥ c n-1 , c n-1 and c n satisfy: c n > c n-1 or c n = c n-1 or c n < c n-1 .

10. The multi-wavelength light emitting diode according to claim 1, wherein The thicknesses of the barrier layers of the first, second, …, (n−1)th, and nth groups of quantum well light-emitting units are t1, t2, …, t n-1 , t n ; each thickness satisfies: t n ≥t n-1 , t1≥t2≥…≥t n-1 .

11. The multi-wavelength light-emitting diode according to claim 1, wherein Define one well layer and one barrier layer in the quantum well light-emitting unit as one period. The numbers of the periodic structures of the first group, the second group, …, the (n - 1)-th group, and the n-th group of quantum well light-emitting units are X1, X2, …, X n-1 , X n ; where X n-1 > X1, X n-1 > X n , X n-1 > X2.

12. The light-emitting module is characterized in that, Comprising the multi-wavelength light-emitting diode according to any one of claims 1 to 11, and the light generated by the light-emitting diode is mixed to generate white light through a wavelength conversion unit.

Images