Semiconductor light emitting structure and preparation method thereof

Abstract

The present invention provides a semiconductor light-emitting structure and a preparation method thereof. The semiconductor light-emitting structure comprises a first limiting layer, a first waveguide layer, an active layer, a second waveguide layer and a second limiting layer stacked in sequence; the material of the first waveguide layer is Al x Ga 1‑x As, the first waveguide layer includes a first first sub-waveguide layer to an Mth first sub-waveguide layer stacked; for any two adjacent first sub-waveguide layers, the Al component x in one first sub-waveguide layer is greater than or equal to 0.5, and the Al component x in the other first sub-waveguide layer is less than or equal to 0.4; and / or the material of the second waveguide layer is Al y Ga 1‑y As, the second waveguide layer includes a first second sub-waveguide layer to an Nth second sub-waveguide layer stacked in layers; for any two adjacent second sub-waveguide layers, the Al composition y in one second sub-waveguide layer is greater than or equal to 0.5, and the Al composition y in the other second sub-waveguide layer is less than or equal to 0.4.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a semiconductor light-emitting structure and a preparation method thereof. Background Art

[0002] Semiconductor light-emitting devices are devices that use certain semiconductor materials as working materials to produce stimulated emission. Their working principle is: through a certain excitation method, a particle population inversion of non-equilibrium carriers is achieved between the energy bands (conduction band and valence band) of the semiconductor material, or between the energy bands of the semiconductor material and the energy levels of impurities (acceptor or donor). When a large number of electrons in the particle population inversion state recombine with holes, stimulated emission occurs. Semiconductor light-emitting devices are widely used due to their small size and high electro-optical conversion efficiency. Summary of the invention

[0003] Therefore, the technical problem to be solved by the present invention is how to effectively improve the electro-optical conversion efficiency, thereby providing a semiconductor light-emitting structure and a preparation method thereof.

[0004] The present invention provides a semiconductor light emitting structure, comprising: a first limiting layer, a first waveguide layer, an active layer, a second waveguide layer and a second limiting layer stacked in sequence; wherein the material of the first waveguide layer is Al x Ga 1-x As, the first waveguide layer includes a first first sub-waveguide layer to an Mth first sub-waveguide layer stacked, M is an integer greater than or equal to 3; for any two adjacent first sub-waveguide layers, the Al component x in one first sub-waveguide layer is greater than or equal to 0.5, and the Al component x in the other first sub-waveguide layer is less than or equal to 0.4; and / or the material of the second waveguide layer is Al y Ga 1-y As, the second waveguide layer includes a first second sub-waveguide layer to an Nth second sub-waveguide layer stacked in layers, where N is an integer greater than or equal to 3; for any two adjacent second sub-waveguide layers, the Al component y in one second sub-waveguide layer is greater than or equal to 0.5, and the Al component y in the other second sub-waveguide layer is less than or equal to 0.4.

[0005] Optionally, the first first sub-waveguide layer to the Mth first sub-waveguide layer are arranged along the direction from the active layer to the first limiting layer; wherein, for any two adjacent first sub-waveguide layers, the Al component x in one first sub-waveguide layer is greater than or equal to 0.5, and the Al component x in the other first sub-waveguide layer is less than or equal to 0.4, including: the Al component in the first sub-waveguide layer of the odd-numbered layer is greater than or equal to 0.5, and the Al component in the first sub-waveguide layer of the even-numbered layer is less than or equal to 0.4; or, the Al component in the first sub-waveguide layer of the odd-numbered layer is less than or equal to 0.4, and the Al component in the first sub-waveguide layer of the even-numbered layer is greater than or equal to 0.5.

[0006] Optionally, the first second sub-waveguide layer to the Nth second sub-waveguide layer are arranged along the direction from the active layer to the second confinement layer; wherein, for any two adjacent second sub-waveguide layers, the Al component y in one second sub-waveguide layer is greater than or equal to 0.5, and the Al component y in the other second sub-waveguide layer is less than or equal to 0.4, including: the Al component in the second sub-waveguide layer of the odd-numbered layers is greater than or equal to 0.5, and the Al component in the second sub-waveguide layer of the even-numbered layers is less than or equal to 0.4; or, the Al component in the second sub-waveguide layer of the odd-numbered layers is less than or equal to 0.4, and the Al component in the second sub-waveguide layer of the even-numbered layers is greater than or equal to 0.5.

[0007] Optionally, the first first sub-waveguide layer to the Mth first sub-waveguide layer include multiple layers of even-numbered first sub-waveguide layers; when the Al component in the first sub-waveguide layer of the even-numbered layer is less than or equal to 0.4, the Al component in the multiple layers of even-numbered first sub-waveguide layers increases layer by layer from the active layer to the first confinement layer.

[0008] Optionally, when the Al composition in the first sub-waveguide layer of the odd-numbered layers is less than or equal to 0.4, the Al composition in the first sub-waveguide layers of the odd-numbered layers increases layer by layer from the active layer to the first confinement layer.

[0009] Optionally, when the Al component in the first sub-waveguide layer of the odd-numbered layer is greater than or equal to 0.5, the Al components in the first sub-waveguide layers of the multiple odd-numbered layers are equal, or the Al components in the first sub-waveguide layers of the multiple odd-numbered layers increase layer by layer from the active layer to the first confinement layer; when the Al component in the first sub-waveguide layer of the even-numbered layer is greater than or equal to 0.5, the Al components in the first sub-waveguide layers of the multiple even-numbered layers are equal, or the Al components in the first sub-waveguide layers of the multiple even-numbered layers increase layer by layer from the active layer to the first confinement layer.

[0010] Optionally, the first second sub-waveguide layer to the Nth second sub-waveguide layer include multiple layers of even-numbered second sub-waveguide layers; when the Al component in the second sub-waveguide layer of the even-numbered layer is less than or equal to 0.4, the Al component in the multiple layers of even-numbered second sub-waveguide layers increases layer by layer from the active layer to the second confinement layer.

[0011] Optionally, when the Al composition in the second sub-waveguide layer of the odd-numbered layers is less than or equal to 0.4, the Al composition in the second sub-waveguide layers of the odd-numbered layers increases layer by layer from the active layer to the second confinement layer.

[0012] Optionally, when the Al component in the second sub-waveguide layer of the odd-numbered layer is greater than or equal to 0.5, the Al components in the second sub-waveguide layers of the multiple odd-numbered layers are equal, or the Al components in the second sub-waveguide layers of the multiple odd-numbered layers increase layer by layer from the active layer to the second confinement layer; when the Al component in the second sub-waveguide layer of the even-numbered layer is greater than or equal to 0.5, the Al components in the second sub-waveguide layers of the multiple even-numbered layers are equal, or the Al components in the second sub-waveguide layers of the multiple even-numbered layers increase layer by layer from the active layer to the second confinement layer.

[0013] Optionally, for any two adjacent first sub-waveguide layers, the Al component x in one first sub-waveguide layer is greater than or equal to 0.5, and the Al component x in the other first sub-waveguide layer is less than or equal to 0.4 and greater than or equal to 0.3.

[0014] Optionally, for any two adjacent second sub-waveguide layers, the Al component y in one second sub-waveguide layer is greater than or equal to 0.5, and the Al component y in the other second sub-waveguide layer is less than or equal to 0.4 and greater than or equal to 0.3.

[0015] Optionally, the thickness of the first sub-waveguide layer is less than or equal to 50 nm; the thickness of the second sub-waveguide layer is less than or equal to 50 nm.

[0016] The present application also provides a method for preparing a semiconductor light-emitting structure, comprising: forming a first limiting layer, a first waveguide layer, an active layer, a second waveguide layer, and a second limiting layer stacked in sequence; wherein the material of the first waveguide layer is Al x Ga 1-x As, the first waveguide layer includes a first first sub-waveguide layer to an Mth first sub-waveguide layer stacked, M is an integer greater than or equal to 3; for any two adjacent first sub-waveguide layers, the Al component x in one first sub-waveguide layer is greater than or equal to 0.5, and the Al component x in the other first sub-waveguide layer is less than or equal to 0.4; and / or the material of the second waveguide layer is Al y Ga 1-yAs, the second waveguide layer includes a first second sub-waveguide layer to an Nth second sub-waveguide layer stacked in layers, where N is an integer greater than or equal to 3; for any two adjacent second sub-waveguide layers, the Al component y in one second sub-waveguide layer is greater than or equal to 0.5, and the Al component y in the other second sub-waveguide layer is less than or equal to 0.4. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic diagram of a semiconductor light emitting structure according to an embodiment of the present application;

[0019] Figure 2 is a schematic diagram of a second waveguide layer in a semiconductor light emitting structure according to an embodiment of the present application;

[0020] Figure 3 Schematic diagram of the refractive index and light intensity along the fast axis direction of the semiconductor light emitting structure of Comparative Example 1;

[0021] Figure 4 A schematic diagram of the refractive index and light intensity of the semiconductor light emitting structure of Test Example 1 along the fast axis direction;

[0022] Figure 5 Schematic diagram of light loss of semiconductor light emitting structures of Comparative Example 1 and Test Example 1;

[0023] Figure 6 Schematic diagram of the power and voltage of the semiconductor light emitting structure of Test Example 1 and Comparative Example 1 as the current changes;

[0024] Figure 7 A schematic diagram of the refractive index and light intensity along the fast axis direction of the semiconductor light emitting structure of Test Example 2;

[0025] Figure 8 Schematic diagram of the power and voltage of the semiconductor light emitting structure of Test Example 2 and Comparative Example 1 as the current changes;

[0026] Fig. 9 Schematic diagram of the refractive index and light intensity of the semiconductor light-emitting structure of Test Example 3 along the fast axis. DETAILED DESCRIPTION

[0027] Semiconductor-pumped alkali metal vapor lasers have been a hot topic in the field of lasers in recent years. 766nm, 780nm and 852nm correspond to the absorption peaks of alkali metal elements potassium, rubidium and cesium, respectively. Therefore, semiconductor laser chips in the 766nm-852nm band are the key core light sources of alkali metal lasers. Compared with the more than 900 nm band, the 766nm-852nm band is limited by the higher photon energy in this band, and the requirements for semiconductor materials in laser chip design are more stringent. There are two materials used in the waveguide layer of laser chips in this band, namely AlGaInP and AlGaAs. The device made of the former has better reliability, but the carrier injection efficiency of the laser chip whose waveguide layer material is AlGaInP is not high, and the electro-optical conversion efficiency of the laser chip is limited. The electro-optical conversion efficiency of the laser chip whose waveguide layer material is AlGaInP is lower than that of the laser chip whose waveguide layer material is AlGaAs. Laser chips that pursue high electro-optical conversion efficiency must adopt AlGaAs-based technology routes. The efficiency loss of the electro-optical conversion efficiency of laser chips in the 766nm-852nm band mainly comes from the insufficient confinement of carriers, the escape of carriers from the quantum well, the reduction of recombination and the reduction of quantum efficiency.

[0028] After research, it was found that one way to solve this problem is to increase the band gap of the material of the waveguide layer. However, the Al component corresponding to the transition point from direct band gap to indirect band gap of AlGaAs is 0.45, which means that the increase in band gap after the Al component in AlGaAs is greater than 0.45 has little significance for carrier restriction, and AlGaAs with an Al component greater than 0.45 has poor electron mobility and is difficult to be used as the n-side material of the pn junction of a laser chip; AlGaAs also has the problem of a sudden increase in the light scattering cross section near the Al component of 0.45, which brings about a surge in light loss and a rapid deterioration in electro-optical conversion efficiency. Under the above limitations, conventional laser chips based on AlGaAs materials cannot simultaneously meet the design requirements of high carrier restriction capability, high light restriction capability, and low light loss in the 766nm-852nm band, and it is difficult to further improve the electro-optical conversion efficiency.

[0029] In order to solve the above problems, the present invention proposes a semiconductor light-emitting structure and a preparation method thereof, which breaks through the upper limit of the capabilities of traditional materials and structures and effectively improves the electro-optical conversion efficiency.

[0030] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are 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 understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0032] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] An embodiment of the present invention provides a semiconductor light emitting structure, referring to Figure 1 , comprising: a first limiting layer 110, a first waveguide layer 120, an active layer 130, a second waveguide layer 140 and a second limiting layer 150 stacked in sequence;

[0034] The material of the first waveguide layer 120 is Al x Ga 1-x As, the first waveguide layer 120 includes a first first sub-waveguide layer to an Mth first sub-waveguide layer stacked, where M is an integer greater than or equal to 3; for any two adjacent first sub-waveguide layers, the Al component x in one first sub-waveguide layer is greater than or equal to 0.5, and the Al component x in the other first sub-waveguide layer is less than or equal to 0.4; and / or, the material of the second waveguide layer 140 is Al y Ga 1-y As, the second waveguide layer 140 includes a first second sub-waveguide layer to an Nth second sub-waveguide layer stacked, where N is an integer greater than or equal to 3; for any two adjacent second sub-waveguide layers, the Al component y in one second sub-waveguide layer is greater than or equal to 0.5, and the Al component y in the other second sub-waveguide layer is less than or equal to 0.4.

[0035] In this embodiment, when the first waveguide layer 120 includes the first layer of stacked first sub-waveguide layers to the Mth layer of first sub-waveguide layers, for any two adjacent first sub-waveguide layers, when the Al component x in one first sub-waveguide layer is greater than or equal to 0.5 and the Al component x in the other first sub-waveguide layer is less than or equal to 0.4, the band gap of the first sub-waveguide layer with an Al component x greater than or equal to 0.5 is larger, and the first sub-waveguide layer with an Al component x greater than or equal to 0.5 has a greater ability to restrict carriers, reduces the number of carriers escaping from the quantum well of the active layer 130, increases the degree of carrier recombination in the active layer 130, and improves the quantum efficiency, while the refractive index of the first sub-waveguide layer with an Al component x less than or equal to 0.4 is larger, and the first sub-waveguide layer with an Al component x less than or equal to 0.4 is used to improve the ability to restrict the light field. The electron mobility of the first sub-waveguide layer corresponding to the Al component x less than or equal to 0.4 is larger, the light scattering cross section is inversely proportional to the electron mobility, the light scattering cross section is lower, and the light loss is reduced. In summary, the design requirements of greater carrier restriction capability, greater light field restriction capability and lower light loss are taken into account, and the electro-optical conversion efficiency is effectively improved.

[0036] In this embodiment, when the first waveguide layer 120 includes the stacked first to M-th first sub-waveguide layers, the Al component in the first sub-waveguide layer largely avoids the numerical point of 0.45, the optical loss is reduced, and the electron mobility is improved.

[0037] In this embodiment, when the second waveguide layer 140 includes the first layer of the second sub-waveguide layer to the Nth layer of the second sub-waveguide layer, for any two adjacent second sub-waveguide layers, when the Al component y in one second sub-waveguide layer is greater than or equal to 0.5 and the Al component y in the other second sub-waveguide layer is less than or equal to 0.4, the band gap of the second sub-waveguide layer with the Al component y greater than or equal to 0.5 is larger, and the second sub-waveguide layer with the Al component y greater than or equal to 0.5 has a greater ability to restrict carriers, reduces the number of carriers escaping from the quantum well of the active layer 130, increases the degree of carrier recombination in the active layer 130, and improves the quantum efficiency, while the refractive index of the second sub-waveguide layer with the Al component y less than or equal to 0.4 is larger, and the second sub-waveguide layer with the Al component y less than or equal to 0.4 is used to improve the ability to restrict the light field. The electron mobility of the second sub-waveguide layer corresponding to the Al component y less than or equal to 0.4 is larger, the light scattering cross section is inversely proportional to the electron mobility, the light scattering cross section is lower, and the light loss is reduced. In summary, the design requirements of greater carrier restriction capability, greater light field restriction capability and lower light loss are taken into account, and the electro-optical conversion efficiency is effectively improved.

[0038] In this embodiment, when the second waveguide layer 140 includes the first to Nth second sub-waveguide layers, the Al component in the second sub-waveguide layer largely avoids the value of 0.45, the optical loss is reduced, and the electron mobility is improved.

[0039] In one embodiment, when the first waveguide layer 120 includes a first first sub-waveguide layer to an Mth first sub-waveguide layer stacked, x is a weighted average value based on the thickness of the first sub-waveguide layer between 0.4 and 0.5, so that the first waveguide layer 120 has an equivalent thickness to Al x1 Ga 1-x1 Refractive index, band gap and stress values ​​of As (0.4<x1<0.5).

[0040] In one embodiment, when the second waveguide layer 140 includes the first second sub-waveguide layer to the Nth second sub-waveguide layer, the weighted average value of y based on the thickness of the second sub-waveguide layer is between 0.4 and 0.5, so that the second waveguide layer 140 has an equivalent value to Al y1 Ga 1-y1 Refractive index, band gap and stress values ​​of As (0.4<y1<0.5).

[0041] The semiconductor light emitting structure includes an edge emitting semiconductor laser.

[0042] In one embodiment, the central wavelength of the light emitted by the semiconductor light emitting structure can be selected between 766 nm and 852 nm.

[0043] In this embodiment, the second waveguide layer 140 includes a first second sub-waveguide layer to an Nth second sub-waveguide layer stacked, N is an integer greater than or equal to 3, and for any two adjacent second sub-waveguide layers, the Al composition y in one second sub-waveguide layer is greater than or equal to 0.5, and the Al composition y in the other second sub-waveguide layer is less than or equal to 0.4. For example, refer to Figure 2 , N is equal to 8 as an example, the second waveguide layer 140 includes a first second sub-waveguide layer 141, a second second sub-waveguide layer 142, a third second sub-waveguide layer 143, a fourth second sub-waveguide layer 144, a fifth second sub-waveguide layer 145, a sixth second sub-waveguide layer 146, a seventh second sub-waveguide layer 147 and an eighth second sub-waveguide layer 148 stacked. It should be noted that N can be an even number greater than 3, or an odd number greater than or equal to 3. The number of N can be selected according to actual needs. The first waveguide layer 120 is a single-layer structure.

[0044] In other embodiments, the first waveguide layer 120 includes a first first sub-waveguide layer to an Mth first sub-waveguide layer stacked, M is an integer greater than or equal to 3, and for any two adjacent first sub-waveguide layers, the Al component x in one first sub-waveguide layer is greater than or equal to 0.5, and the Al component x in the other first sub-waveguide layer is less than or equal to 0.4. It should be noted that M can be an even number greater than 3, or an odd number greater than or equal to 3. The number of M can be selected according to actual needs. The second waveguide layer is a single-layer structure.

[0045] In other embodiments, the first waveguide layer 120 includes a first layer of stacked first sub-waveguide layers to an Mth layer of first sub-waveguide layers, M is an integer greater than or equal to 3, for any two adjacent first sub-waveguide layers, the Al component x in one first sub-waveguide layer is greater than or equal to 0.5, and the Al component x in the other first sub-waveguide layer is less than or equal to 0.4, and the second waveguide layer 140 includes a first layer of stacked second sub-waveguide layers to an Nth layer of second sub-waveguide layers, N is an integer greater than or equal to 3, for any two adjacent second sub-waveguide layers, the Al component y in one second sub-waveguide layer is greater than or equal to 0.5, and the Al component y in the other second sub-waveguide layer is less than or equal to 0.4. It should be noted that N can be an even number greater than 3, or an odd number greater than or equal to 3. The number of N can be selected according to actual needs. It should be noted that M can be an even number greater than 3, or an odd number greater than or equal to 3. The number of M can be selected according to actual needs.

[0046] In one embodiment, when the first waveguide layer 120 includes stacked first to M-th first sub-waveguide layers, the first to M-th first sub-waveguide layers are arranged along a direction from the active layer 130 to the first confinement layer 110; wherein, for any two adjacent first sub-waveguide layers, the Al component x in one first sub-waveguide layer is greater than or equal to 0.5, and the Al component x in the other first sub-waveguide layer is less than or equal to 0.4, including: the Al component in the first sub-waveguide layer of the odd-numbered layer is greater than or equal to 0.5, and the Al component in the first sub-waveguide layer of the even-numbered layer is less than or equal to 0.4; or, the Al component in the first sub-waveguide layer of the odd-numbered layer is less than or equal to 0.4, and the Al component in the first sub-waveguide layer of the even-numbered layer is greater than or equal to 0.5.

[0047] In one embodiment, the first first sub-waveguide layer to the Mth first sub-waveguide layer include multiple even-numbered first sub-waveguide layers; when the Al component in the even-numbered first sub-waveguide layer is less than or equal to 0.4, the Al component in the even-numbered first sub-waveguide layer increases layer by layer from the active layer 130 to the first limiting layer 110. That is, the Al component in the even-numbered first sub-waveguide layer closer to the active layer 130 is smaller, the refractive index of the even-numbered first sub-waveguide layer closer to the active layer 130 is larger, and the limiting ability of the light field is increased, the Al component in the even-numbered first sub-waveguide layer farther from the active layer 130 is larger, the band gap in the even-numbered first sub-waveguide layer farther from the active layer 130 is larger, and the limiting ability of the carrier is increased, and the electro-optical conversion efficiency is further improved.

[0048] In one embodiment, when the Al component in the first sub-waveguide layer of the odd-numbered layer is less than or equal to 0.4, the Al component in the first sub-waveguide layer of the odd-numbered layer increases layer by layer from the active layer 130 to the first confinement layer 110. That is, the Al component in the first sub-waveguide layer of the odd-numbered layer closer to the active layer 130 is smaller, and the refractive index of the first sub-waveguide layer of the odd-numbered layer closer to the active layer 130 is larger, thereby increasing the ability to confine the light field, and the Al component in the first sub-waveguide layer of the odd-numbered layer farther from the active layer 130 is larger, and the band gap in the first sub-waveguide layer of the odd-numbered layer farther from the active layer 130 is larger, thereby increasing the ability to confine carriers and further improving the electro-optical conversion efficiency.

[0049] In one embodiment, when the Al composition in the first sub-waveguide layer of the odd-numbered layer is greater than or equal to 0.5, the Al composition in the first sub-waveguide layers of the multiple odd-numbered layers is equal, or the Al composition in the first sub-waveguide layers of the multiple odd-numbered layers increases layer by layer from the active layer to the first confinement layer; when the Al composition in the first sub-waveguide layer of the even-numbered layer is greater than or equal to 0.5, the Al composition in the first sub-waveguide layers of the multiple even-numbered layers is equal, or the Al composition in the first sub-waveguide layers of the multiple even-numbered layers increases layer by layer from the active layer to the first confinement layer.

[0050] In one embodiment, when the second waveguide layer 140 includes a first second sub-waveguide layer to an N-th second sub-waveguide layer stacked, the first second sub-waveguide layer to the N-th second sub-waveguide layer are arranged along a direction from the active layer 130 to the second confinement layer 150; wherein, for any two adjacent second sub-waveguide layers, the Al component y in one second sub-waveguide layer is greater than or equal to 0.5, and the Al component y in the other second sub-waveguide layer is less than or equal to 0.4, including: the Al component in the second sub-waveguide layer of the odd-numbered layer is greater than or equal to 0.5, and the Al component in the second sub-waveguide layer of the even-numbered layer is less than or equal to 0.4; or, the Al component in the second sub-waveguide layer of the odd-numbered layer is less than or equal to 0.4, and the Al component in the second sub-waveguide layer of the even-numbered layer is greater than or equal to 0.5. Among them, the Al component in the second sub-waveguide layer of the odd-numbered layers is greater than or equal to 0.5, and the Al component in the second sub-waveguide layer of the even-numbered layers is less than or equal to 0.4. Exemplarily, in a specific embodiment, N=8, the Al components in the first second sub-waveguide layer 141, the third second sub-waveguide layer 143, the fifth second sub-waveguide layer 145, and the seventh second sub-waveguide layer 147 are respectively greater than or equal to 0.5, and the Al components in the second second sub-waveguide layer 142, the fourth second sub-waveguide layer 144, the sixth second sub-waveguide layer 146, and the eighth second sub-waveguide layer 148 are respectively less than or equal to 0.4. Among them, the Al component in the second sub-waveguide layer of the odd-numbered layers is less than or equal to 0.4, and the Al component in the second sub-waveguide layer of the even-numbered layers is greater than or equal to 0.5. Exemplarily, in a specific embodiment, N=8, the Al components in the first second sub-waveguide layer 141, the third second sub-waveguide layer 143, the fifth second sub-waveguide layer 145, and the seventh second sub-waveguide layer 147 are respectively less than or equal to 0.4, and the Al components in the second second sub-waveguide layer 142, the fourth second sub-waveguide layer 144, the sixth second sub-waveguide layer 146, and the eighth second sub-waveguide layer 148 are respectively greater than or equal to 0.5.

[0051] In one embodiment, the first second sub-waveguide layer to the Nth second sub-waveguide layer include multiple even-numbered second sub-waveguide layers; when the Al component in the even-numbered second sub-waveguide layer is less than or equal to 0.4, the Al component in the multiple even-numbered second sub-waveguide layers increases layer by layer from the active layer to the second confinement layer. Exemplarily, when N=8, when the Al component in the even-numbered second sub-waveguide layer is less than or equal to 0.4, the Al component in the second second sub-waveguide layer 142, the fourth second sub-waveguide layer 144, the sixth second sub-waveguide layer 146, and the eighth second sub-waveguide layer 148 increases layer by layer. That is to say, the Al component in the second sub-waveguide layer of the even-numbered layer closer to the active layer 130 is smaller, and the refractive index of the second sub-waveguide layer of the even-numbered layer closer to the active layer 130 is larger, which increases the ability to limit the light field; the Al component in the second sub-waveguide layer of the even-numbered layer farther away from the active layer 130 is larger, and the band gap in the second sub-waveguide layer of the even-numbered layer farther away from the active layer 130 is larger, which increases the ability to limit carriers and further improves the electro-optical conversion efficiency.

[0052] In one embodiment, when the Al component in the second sub-waveguide layer of the odd-numbered layer is less than or equal to 0.4, the Al component in the second sub-waveguide layer of the plurality of odd-numbered layers increases layer by layer from the active layer to the second limiting layer. Exemplarily, when N=8, when the Al component in the second sub-waveguide layer of the odd-numbered layer is less than or equal to 0.4, the Al component in the first second sub-waveguide layer 141, the third second sub-waveguide layer 143, the fifth second sub-waveguide layer 145 and the seventh second sub-waveguide layer 147 increases layer by layer. That is, the smaller the Al component in the second sub-waveguide layer of the odd-numbered layer closer to the active layer 130, the greater the refractive index of the second sub-waveguide layer of the odd-numbered layer closer to the active layer 130, and the greater the ability to limit the light field, the greater the Al component in the second sub-waveguide layer of the odd-numbered layer farther away from the active layer 130, the greater the band gap in the second sub-waveguide layer of the odd-numbered layer farther away from the active layer 130, and the ability to limit the carriers is increased, further improving the electro-optical conversion efficiency.

[0053] In one embodiment, when the Al composition in the second sub-waveguide layer of the odd-numbered layer is greater than or equal to 0.5, the Al composition in the second sub-waveguide layers of the plurality of odd-numbered layers is equal, or the Al composition in the second sub-waveguide layers of the plurality of odd-numbered layers increases layer by layer from the active layer to the second confinement layer; when the Al composition in the second sub-waveguide layer of the even-numbered layer is greater than or equal to 0.5, the Al composition in the second sub-waveguide layers of the plurality of even-numbered layers is equal, or the Al composition in the second sub-waveguide layers of the plurality of even-numbered layers increases layer by layer from the active layer to the second confinement layer.

[0054] In one embodiment, for any two adjacent first sub-waveguide layers, the Al composition x in one of the first sub-waveguide layers is greater than or equal to 0.5, such as 0.5, 0.55 or 0.6, and the Al composition x in the other first sub-waveguide layer is less than or equal to 0.4 and greater than or equal to 0.3.

[0055] In one embodiment, for any two adjacent second sub-waveguide layers, the Al composition y in one second sub-waveguide layer is greater than or equal to 0.5, such as 0.5, 0.55 or 0.6, and the Al composition y in the other second sub-waveguide layer is less than or equal to 0.4 and greater than or equal to 0.3.

[0056] In one embodiment, the thickness of the first sub-waveguide layer is less than or equal to 50 nm, such as 50 nm, 40 nm, 30 nm, 20 nm or 10 nm; the thickness of the second sub-waveguide layer is less than or equal to 50 nm, such as 50 nm, 40 nm, 30 nm, 20 nm or 10 nm.

[0057] The thickness of the first sub-waveguide layer is less than or equal to 50 nm, and the optical thickness of the first sub-waveguide layer is greatly different from the light-emitting wavelength of the semiconductor light-emitting structure, thereby reducing the grating modulation effect of the first waveguide layer 120 on the laser by forming a grating-like structure, thereby reducing the interference with the resonance of the normal laser.

[0058] The thickness of the second sub-waveguide layer is less than or equal to 50 nm, and the optical thickness of the second sub-waveguide layer is greatly different from the light-emitting wavelength of the semiconductor light-emitting structure, thereby reducing the grating modulation effect of the second waveguide layer 140 on the laser by forming a grating-like structure, thereby reducing the interference with the resonance of the normal laser.

[0059] Comparative Example 1: The semiconductor light emitting structure includes a semiconductor substrate layer, a first limiting layer, a first waveguide layer, an active layer, a second waveguide layer and a second limiting layer stacked in sequence, and the material of the first waveguide layer is Al 0.45 Ga 0.55 As, the material of the second waveguide layer is Al 0.45 Ga 0.55 As, the semiconductor substrate layer, the first confinement layer, the active layer and the second confinement layer of the comparative example 1 are respectively the same as the semiconductor substrate layer, the first confinement layer, the active layer and the second confinement layer of the above embodiment.

[0060] Test Example 1: The semiconductor light emitting structure includes a semiconductor substrate layer, a first confinement layer, a first waveguide layer, an active layer, a second waveguide layer, and a second confinement layer stacked in sequence, and the material of the first waveguide layer is Al x Ga 1-xAs, the first waveguide layer includes a first first sub-waveguide layer to an Mth first sub-waveguide layer stacked, the Al composition of the first sub-waveguide layer of the even-numbered layer is less than or equal to 0.4, the Al composition of the first sub-waveguide layer of the even-numbered layer increases from 0.3 to 0.4 layer by layer from the active layer 130 to the first confinement layer 110, and the Al composition of the first sub-waveguide layer of the odd-numbered layer is 0.55. The second waveguide layer of Test Example 1 is the same as the second waveguide layer of Comparative Example 1.

[0061] Figure 3 Schematic diagram of the refractive index and light intensity of the semiconductor light emitting structure of Comparative Example 1 along the fast axis direction. Figure 3 In the figure, L1 is the change curve of the refractive index of the semiconductor light emitting structure along the fast axis direction, and L2 is the change curve of the light intensity of the fundamental mode of the semiconductor light emitting structure along the fast axis direction. Figure 3 The horizontal axis is the position of the semiconductor structure in the fast axis direction. Figure 3 The vertical axis on the left is the light field intensity. Figure 3 The vertical axis on the right is the refractive index. Figure 4 Schematic diagram of the refractive index and light intensity of the semiconductor light emitting structure in Test Example 1 along the fast axis direction. Figure 4 In the figure, L3 is the change curve of the refractive index of the semiconductor light emitting structure along the fast axis direction, and L4 is the change curve of the light intensity of the fundamental mode of the semiconductor light emitting structure along the fast axis direction. Figure 4 The horizontal axis is the position of the semiconductor structure in the fast axis direction. Figure 4 The vertical axis on the left is the light field intensity. Figure 4 The vertical axis on the right is the refractive index. Figure 5 Schematic diagram of light loss of semiconductor light emitting structures of comparative example 1 and test example 1. Figure 5 , L5 is a curve showing a change in the optical loss of the semiconductor light emitting structure of comparative example 1 along the fast axis direction, and L6 is a curve showing a change in the optical loss of the semiconductor light emitting structure of test example 1 along the fast axis direction. Figure 5 The horizontal axis is the position of the semiconductor structure in the fast axis direction. Figure 5 The vertical axis is the optical loss. Figure 6 , L82 is a curve showing a change in power of the semiconductor light emitting structure of test example 1 as the current changes, L81 is a curve showing a change in voltage of the semiconductor light emitting structure of test example 1 as the current changes, L71 is a curve showing a change in voltage of the semiconductor light emitting structure of comparative example 1 as the current changes, and L72 is a curve showing a change in power of the semiconductor light emitting structure of comparative example 1 as the current changes, Figure 6 The horizontal axis is the current of the semiconductor structure, Figure 6 The vertical axis on the left is the power of the semiconductor structure. Figure 6 The vertical axis on the right is the voltage of the semiconductor structure.

[0062] The light confinement factor of the quantum well of the semiconductor light-emitting structure in Test Example 1 is about 0.8%, and both the light field intensity and the light confinement factor meet the design requirements of the semiconductor light-emitting structure in the 766nm-852nm band. Compared with Comparative Example 1, since the first waveguide layer in Test Example 1 includes the stacked first layer of the first sub-waveguide layer to the Mth layer of the first sub-waveguide layer, the Al component in the first sub-waveguide layer avoids 0.45, and the light loss of the semiconductor light-emitting structure is low. The light loss of the semiconductor light-emitting structure of Test Example 1 is approximately 60% of the light loss of the semiconductor light-emitting structure of Comparative Example 1. The slope efficiency of the semiconductor light-emitting structure of Test Example 1 is increased by 7% compared with the slope efficiency of the semiconductor light-emitting structure of Comparative Example 1. The power of the semiconductor light-emitting structure of Test Example 1 is increased by 2.5W compared with the power of the semiconductor light-emitting structure of Comparative Example 1. The Al component in the first sub-waveguide layer in Test Example 1 avoids 0.45, and x1=0.45 corresponds to Al x1 Ga 1-x1 As has a minimum point in the electron mobility of As, so the electron mobility of the first waveguide layer in Test Example 1 is optimized. Compared with Comparative Example 1, under the condition that the current of the semiconductor light emitting structure of Test Example 1 is 15A and the voltage of the semiconductor light emitting structure of Test Example 1 is 50mV lower than that of the semiconductor light emitting structure of Comparative Example 1, the electro-optical conversion efficiency of the semiconductor light emitting structure of Test Example 1 is improved by 8% over that of the semiconductor light emitting structure of Comparative Example 1.

[0063] Test Example 2: The semiconductor light emitting structure includes a semiconductor substrate layer, a first confinement layer, a first waveguide layer, an active layer, a second waveguide layer and a second confinement layer stacked in sequence, and the material of the second waveguide layer is Al y Ga 1-y As, the second waveguide layer includes the first second sub-waveguide layer to the Nth second sub-waveguide layer stacked, the Al composition of the second sub-waveguide layer in the even-numbered layer is equal to 0.4, and the Al composition of the second sub-waveguide layer in the odd-numbered layer is 0.5. The first waveguide layer of Test Example 2 is the same as the first waveguide layer of Comparative Example 1.

[0064] Figure 7 Schematic diagram of the refractive index and light intensity of the semiconductor light emitting structure of Test Example 2 along the fast axis direction. Figure 7 In the figure, L91 is the change curve of the refractive index of the semiconductor light emitting structure along the fast axis direction, and L92 is the change curve of the light intensity of the fundamental mode of the semiconductor light emitting structure along the fast axis direction. Figure 7 The horizontal axis is the position of the semiconductor structure in the fast axis direction. Figure 7 The vertical axis on the left is the light field intensity. Figure 7 The vertical axis on the right is the refractive index. Figure 8, L104 is a curve showing a change in power of the semiconductor light emitting structure of Test Example 2 as the current changes, L103 is a curve showing a change in voltage of the semiconductor light emitting structure of Test Example 2 as the current changes, L101 is a curve showing a change in voltage of the semiconductor light emitting structure of Comparative Example 1 as the current changes, and L102 is a curve showing a change in power of the semiconductor light emitting structure of Comparative Example 1 as the current changes, Figure 8 The horizontal axis is the current of the semiconductor structure, Figure 8 The vertical axis on the left is the power of the semiconductor structure. Figure 8 The vertical axis on the right is the voltage of the semiconductor structure.

[0065] The equivalent refractive index of the second waveguide layer of Test Example 2 is close to that of the second waveguide layer of Comparative Example 1, the optical field intensity distribution of the fundamental mode of Test Example 2 is basically close to that of the fundamental mode of Comparative Example 1, and the optical confinement capability of the second waveguide layer of Test Example 2 is basically close to that of the second waveguide layer of Comparative Example 1. The electron mobility of the second waveguide layer of Test Example 2 is basically equivalent to that of Al 0.42 Ga 0.58 As electron mobility. The band gap of the second waveguide layer of Test Example 2 is equivalent to the band gap of the second waveguide layer of Comparative Example 1. The voltage of the semiconductor light-emitting structure of Test Example 2 is close to the voltage of the semiconductor light-emitting structure of Comparative Example 1. Since the second waveguide layer includes multiple second sub-waveguide layers with an Al component of 0.5, the electrons leaking from the quantum well to the second waveguide layer are suppressed, and the internal quantum efficiency of Test Example 2 is 3% higher than that of Comparative Example 1, the power of the semiconductor light-emitting structure of Test Example 2 is 0.8W higher than that of the semiconductor light-emitting structure of Comparative Example 1, and the electro-optical conversion efficiency of the semiconductor light-emitting structure of Test Example 2 at 15A is 3% higher than that of the semiconductor light-emitting structure of Comparative Example 1 at 15A.

[0066] Test Example 3: The semiconductor light emitting structure includes a semiconductor substrate layer, a first confinement layer, a first waveguide layer, an active layer, a second waveguide layer, and a second confinement layer stacked in sequence; the material of the first waveguide layer is Al x Ga 1-x As, the first waveguide layer includes the first first sub-waveguide layer to the Mth first sub-waveguide layer stacked, the Al component in the first sub-waveguide layer of the even-numbered layer is less than or equal to 0.4, the Al component in the first sub-waveguide layer of the even-numbered layer increases from 0.3 to 0.4 layer by layer from the active layer 130 to the first restriction layer 110, and the Al component in the first sub-waveguide layer of the odd-numbered layer is 0.55; the material of the second waveguide layer 140 is Al y Ga 1-yAs, the second waveguide layer 140 includes the first second sub-waveguide layer to the Nth second sub-waveguide layer stacked, the Al composition of the second sub-waveguide layer in the even-numbered layer is less than or equal to 0.4, the Al composition of the second sub-waveguide layer in the multiple even-numbered layers increases from 0.3 to 0.4 layer by layer from the active layer 130 to the second confinement layer, and the Al composition of the second sub-waveguide layer in the odd-numbered layer is 0.55.

[0067] Fig. 9 Schematic diagram of the refractive index and light intensity of the semiconductor light emitting structure along the fast axis of Test Example 3. Fig. 9 In the figure, L202 is the change curve of the refractive index of the semiconductor light emitting structure along the fast axis direction, and L201 is the change curve of the light intensity of the fundamental mode of the semiconductor light emitting structure along the fast axis direction. Fig. 9 The horizontal axis is the position of the semiconductor structure in the fast axis direction. Fig. 9 The vertical axis on the left is the light field intensity. Fig. 9 The vertical axis on the right is the refractive index.

[0068] Since the first waveguide layer includes the first to M-th first sub-waveguide layers as described above, and the second waveguide layer 140 includes the first to N-th second sub-waveguide layers as described above, the power and electro-optical conversion efficiency of the semiconductor light emitting structure are further improved.

[0069] The present application also provides a method for preparing a semiconductor light-emitting structure, comprising: forming a first limiting layer, a first waveguide layer, an active layer, a second waveguide layer, and a second limiting layer stacked in sequence; wherein the material of the first waveguide layer is Al x Ga 1-x As, the first waveguide layer includes a first first sub-waveguide layer to an Mth first sub-waveguide layer stacked, M is an integer greater than or equal to 3; for any two adjacent first sub-waveguide layers, the Al component x in one first sub-waveguide layer is greater than or equal to 0.5, and the Al component x in the other first sub-waveguide layer is less than or equal to 0.4; and / or the material of the second waveguide layer is Al y Ga 1-y As, the second waveguide layer includes a first second sub-waveguide layer to an Nth second sub-waveguide layer stacked in layers, where N is an integer greater than or equal to 3; for any two adjacent second sub-waveguide layers, an Al component y in one second sub-waveguide layer is greater than or equal to 0.5, and an Al component x in the other second sub-waveguide layer is less than or equal to 0.4.

[0070] The specific description of the first waveguide layer and the second waveguide layer refers to the description of the aforementioned embodiment and will not be described in detail again.

[0071] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A semiconductor light emitting structure, characterized in that: include: A first confinement layer, a first waveguide layer, an active layer, a second waveguide layer and a second confinement layer stacked in sequence; Wherein, the material of the first waveguide layer is Al x Ga 1-x As, the first waveguide layer includes a first first sub-waveguide layer to an Mth first sub-waveguide layer stacked in layers, where M is an integer greater than or equal to 3; for any two adjacent first sub-waveguide layers, the Al component x in one first sub-waveguide layer is greater than or equal to 0.5, and the Al component x in the other first sub-waveguide layer is less than or equal to 0.4; And / or, the material of the second waveguide layer is Al y Ga 1-y As, the second waveguide layer includes a first second sub-waveguide layer to an Nth second sub-waveguide layer stacked in layers, where N is an integer greater than or equal to 3; for any two adjacent second sub-waveguide layers, the Al component y in one second sub-waveguide layer is greater than or equal to 0.5, and the Al component y in the other second sub-waveguide layer is less than or equal to 0.

4.

2. The semiconductor light emitting structure according to claim 1, characterized in that: The first first sub-waveguide layer to the Mth first sub-waveguide layer are arranged along a direction from the active layer to the first confinement layer; Wherein, for any two adjacent first sub-waveguide layers, the Al component x in one first sub-waveguide layer is greater than or equal to 0.5, and the Al component x in the other first sub-waveguide layer is less than or equal to 0.4, including: the Al component in the first sub-waveguide layer of the odd-numbered layer is greater than or equal to 0.5, and the Al component in the first sub-waveguide layer of the even-numbered layer is less than or equal to 0.4; or, the Al component in the first sub-waveguide layer of the odd-numbered layer is less than or equal to 0.4, and the Al component in the first sub-waveguide layer of the even-numbered layer is greater than or equal to 0.

5.

3. The semiconductor light emitting structure according to claim 1, characterized in that: The first second sub-waveguide layer to the Nth second sub-waveguide layer are arranged along a direction from the active layer to the second confinement layer; Wherein, for any two adjacent second sub-waveguide layers, the Al component y in one second sub-waveguide layer is greater than or equal to 0.5, and the Al component y in the other second sub-waveguide layer is less than or equal to 0.4, including: the Al component in the second sub-waveguide layer of the odd-numbered layer is greater than or equal to 0.5, and the Al component in the second sub-waveguide layer of the even-numbered layer is less than or equal to 0.4; or, the Al component in the second sub-waveguide layer of the odd-numbered layer is less than or equal to 0.4, and the Al component in the second sub-waveguide layer of the even-numbered layer is greater than or equal to 0.

5.

4. The semiconductor light emitting structure according to claim 2, characterized in that: The first first sub-waveguide layer to the Mth first sub-waveguide layer include multiple even-numbered first sub-waveguide layers; when the Al component in the even-numbered first sub-waveguide layers is less than or equal to 0.4, the Al component in the multiple even-numbered first sub-waveguide layers increases layer by layer from the active layer to the first confinement layer.

5. The semiconductor light emitting structure according to claim 2, characterized in that: When the Al composition in the first sub-waveguide layer of the odd-numbered layer is less than or equal to 0.4, the Al composition in the first sub-waveguide layer of the odd-numbered layer increases layer by layer from the active layer to the first confinement layer.

6. The semiconductor light emitting structure according to claim 2, characterized in that: When the Al composition in the first sub-waveguide layer of the odd-numbered layer is greater than or equal to 0.5, the Al composition in the first sub-waveguide layers of the odd-numbered layers is equal, or the Al composition in the first sub-waveguide layers of the odd-numbered layers increases layer by layer from the active layer to the first confinement layer; When the Al composition in the first sub-waveguide layer of the even-numbered layer is greater than or equal to 0.5, the Al composition in the first sub-waveguide layers of multiple even-numbered layers is equal, or the Al composition in the first sub-waveguide layers of multiple even-numbered layers increases layer by layer from the active layer to the first confinement layer.

7. The semiconductor light emitting structure according to claim 3, characterized in that: The first second sub-waveguide layer to the Nth second sub-waveguide layer include multiple layers of second sub-waveguide layers with even numbers; when the Al component in the second sub-waveguide layers with even numbers is less than or equal to 0.4, the Al component in the multiple layers of second sub-waveguide layers with even numbers increases layer by layer from the active layer to the second confinement layer.

8. The semiconductor light emitting structure according to claim 3, characterized in that: When the Al composition in the second sub-waveguide layer of the odd-numbered layers is less than or equal to 0.4, the Al composition in the second sub-waveguide layers of the odd-numbered layers increases layer by layer from the active layer to the second confinement layer.

9. The semiconductor light emitting structure according to claim 3, characterized in that: When the Al composition in the second sub-waveguide layer of the odd-numbered layer is greater than or equal to 0.5, the Al composition in the second sub-waveguide layers of the odd-numbered layers is equal, or the Al composition in the second sub-waveguide layers of the odd-numbered layers increases layer by layer from the active layer to the second confinement layer; When the Al composition in the second sub-waveguide layer of the even-numbered layer is greater than or equal to 0.5, the Al composition in the second sub-waveguide layers of multiple even-numbered layers is equal, or the Al composition in the second sub-waveguide layers of multiple even-numbered layers increases layer by layer from the active layer to the second confinement layer.

10. The semiconductor light emitting structure according to any one of claims 1 to 9, characterized in that: For any two adjacent first sub-waveguide layers, the Al composition x in one first sub-waveguide layer is greater than or equal to 0.5, and the Al composition x in the other first sub-waveguide layer is less than or equal to 0.4 and greater than or equal to 0.

3.

11. The semiconductor light emitting structure according to any one of claims 1 to 9, characterized in that: For any two adjacent second sub-waveguide layers, the Al composition y in one second sub-waveguide layer is greater than or equal to 0.5, and the Al composition y in the other second sub-waveguide layer is less than or equal to 0.4 and greater than or equal to 0.

3.

12. The semiconductor light emitting structure according to claim 1, characterized in that: The thickness of the first sub-waveguide layer is less than or equal to 50 nm; the thickness of the second sub-waveguide layer is less than or equal to 50 nm.

13. A method for preparing a semiconductor light emitting structure as claimed in any one of claims 1 to 12, characterized in that: include: forming a first confinement layer, a first waveguide layer, an active layer, a second waveguide layer, and a second confinement layer stacked in sequence; Wherein, the material of the first waveguide layer is Al x Ga 1-x As, the first waveguide layer includes a first first sub-waveguide layer to an Mth first sub-waveguide layer stacked in layers, where M is an integer greater than or equal to 3; for any two adjacent first sub-waveguide layers, the Al component x in one first sub-waveguide layer is greater than or equal to 0.5, and the Al component x in the other first sub-waveguide layer is less than or equal to 0.4; And / or, the material of the second waveguide layer is Al y Ga 1-y As, the second waveguide layer includes a first second sub-waveguide layer to an Nth second sub-waveguide layer stacked in layers, where N is an integer greater than or equal to 3; for any two adjacent second sub-waveguide layers, the Al component y in one second sub-waveguide layer is greater than or equal to 0.5, and the Al component y in the other second sub-waveguide layer is less than or equal to 0.4.

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