A pure antimonide semiconductor laser

Abstract

The invention provides a pure antimonide semiconductor laser, belonging to the technical field of semiconductor lasers; solves the problems of a classical InGa(As)Sb‑AlGaAsSb I-type strained quantum well, that is, a small valence band step and a weak hole binding ability; comprises a substrate, and a lower confinement layer, a lower waveguide layer, a lower quantum barrier layer, a quantum well, an upper quantum barrier layer, an upper waveguide layer, an upper confinement layer and a protective layer epitaxially grown in sequence on the substrate, wherein the substrate and the protective layer are made of In x Ga 1‑x Sb material, wherein 0.05≤x≤0.65, the lower limiting layer and the upper limiting layer are Ga lattice-matched with the substrate 1‑z1 Al z1 Sb material, the lower waveguide layer, the lower quantum barrier layer, the upper quantum barrier layer, and the upper waveguide layer are made of In lattice matching with the substrate. 1‑x1‑y1 Ga x1 Al y1 Sb material, the quantum well uses In y Ga 1‑ y Sb material, wherein 0.20≤y≤0.60; the present invention is applied to antimonide semiconductors.

Description

Technical Field

[0001] The invention provides a pure antimonide semiconductor laser, belonging to the technical field of semiconductor lasers. Background Art

[0002] Semiconductor lasers have the advantages of small size, light weight, low cost, long life, high reliability, easy modulation and high integration. At present, they have been commercialized on a large scale in the visible and near-infrared bands. However, with the advancement of human science and technology, people's demand for longer wavelengths is also increasing day by day, and the mid-infrared band has gradually become the forefront of semiconductor lasers.

[0003] Antimonide semiconductor materials are ideal material systems that can cover the mid-infrared band because they have a suitable bandgap width and can be regulated by clever band engineering. Due to the excellent properties of the material, antimonide semiconductor lasers have shown great potential in the fields of medical treatment, satellite remote sensing, lidar, gas detection, free space communication, etc. At present, for the 2-3um band, the classic InGa(As)Sb-AlGaAsSb I type strained quantum well shows certain advantages. It uses InGa(As)Sb as the quantum well, AlGaAsSb with a low Al component as the quantum barrier and waveguide layer, and AlGaAsSb with a high Al component as the confinement layer, thereby achieving dual confinement of light and electricity to ensure higher quality laser lasing.

[0004] However, the classic InGa(As)Sb-AlGaAsSb type I strained quantum well is usually epitaxially grown on a GaSb substrate. In order to ensure lattice matching and reduce dislocations and defects, As has to be introduced into the classic structure. However, the addition of As increases the difficulty of structure growth and the cost of epitaxial equipment. In addition, the valence band step of the structure is not large, and the ability to bind holes is not strong, which limits the gain of the laser and its ability to expand to longer wavelengths. Summary of the invention

[0005] In order to solve the problems existing in the classic InGa(As)Sb-AlGaAsSb I-type strained quantum well, the present invention proposes a pure antimonide semiconductor laser, which has only one V group element Sb, reduces the difficulty of epitaxial growth, and eliminates the defects related to As.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a pure antimonide semiconductor laser, comprising a substrate, and a lower confinement layer, a lower waveguide layer, a lower quantum barrier layer, a quantum well, an upper quantum barrier layer, an upper waveguide layer, an upper confinement layer and a protective layer epitaxially grown in sequence on the substrate, wherein the substrate and the protective layer are made of In x Ga 1-xSb material, wherein 0.05≤x≤0.65, the lower limiting layer and the upper limiting layer are Ga lattice-matched with the substrate 1-z1 Al z1 Sb material, wherein 0.48≤z1≤0.98, the lower waveguide layer, the lower quantum barrier layer, the upper quantum barrier layer, and the upper waveguide layer are made of In lattice matching with the substrate. 1-x1-y1 Ga x1 Al y1 Sb material, wherein 0.17≤x1≤0.95, 0.02≤y1≤0.80, the quantum well is made of In y Ga 1-y Sb material, wherein 0.20≤y≤0.60.

[0007] A buffer layer is also arranged between the substrate and the lower limiting layer, and the buffer layer and the substrate are made of the same material.

[0008] The barrier widths of the lower quantum barrier layer and the upper quantum barrier layer are both 16-30 nm.

[0009] The thickness of the quantum well is 6-13 nm, and the number of the quantum wells is 1-3.

[0010] The conductivity type of the substrate is N-type, and the doping concentration is 2E17 to 2E18 cm -3 The conductivity type of the buffer layer is N-type, and the doping concentration is 8E17 to 2E18cm -3 , thickness is 450-550nm.

[0011] The conductivity type of the lower confinement layer is N-type, and the doping concentration is 4E17 to 1E18 cm -3 , thickness is 1600-2400nm;

[0012] The conductivity type of the upper confinement layer is P type, and the doping concentration is 5E18 to 3E19 cm -3 , thickness is 1600-2400nm.

[0013] There is a composition gradient layer between the buffer layer and the lower limiting layer, namely, transition layer 1. The conductivity type of transition layer 1 is N type, and the doping concentration is 8E17 to 1E18cm -3 , thickness is 20-40nm.

[0014] There is a composition gradient layer between the lower limiting layer and the lower waveguide layer, namely, a transition layer 2, with a thickness of 20-40 nm.

[0015] There is a composition gradient layer between the upper limiting layer and the upper waveguide layer, namely, a transition layer 3. The conductivity type of the transition layer 3 is P type, and the doping concentration is 5E18 to 3E19 cm -3, thickness is 20-40nm.

[0016] There is a composition gradient layer between the upper limiting layer and the protective layer, namely the transition layer 4. The conductivity type of the transition layer 4 is P type, and the doping concentration is 5E18 to 3E19 cm -3 , thickness is 20-40nm.

[0017] The beneficial effects of the present invention compared with the prior art are as follows: the pure antimonide laser of the present invention has only one V group element, Sb, which reduces the difficulty of epitaxial growth and eliminates the defects related to As. The energy band order is significantly increased (especially the valence band order), and the binding ability of electrons and holes is significantly enhanced, which is conducive to improving the gain. In addition, the peripheral refractive index is smaller, and the binding ability of light is also improved. And the thermal conductivity is also increased, which is conducive to the development of high-power lasers. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings:

[0019] Figure 1 It is a structural schematic diagram of the present invention;

[0020] Figure 2 Schematic diagram of the flat band energy band of the laser of the present invention;

[0021] Figure 3 Schematic diagram of the refractive index distribution of the laser of the present invention. DETAILED DESCRIPTION

[0022] like Figures 1 to 3 As shown, the present invention provides a pure antimonide semiconductor laser, using In x Ga 1-x Sb material is used as the substrate for epitaxial growth, so that lattice matching of the epitaxial structure can be achieved without introducing As, and a mid-infrared laser structure of pure antimonide can be realized.

[0023] The laser of the present invention is described in detail below based on specific embodiments.

[0024] Example 1

[0025] The specific structure is as follows:

[0026] In x Ga 1-x Sb material substrate, wherein 0.05≤x≤0.65 is epitaxially grown from the substrate in sequence, including a lower confinement layer, a lower waveguide layer, a lower quantum barrier layer, a quantum well, an upper quantum barrier layer, an upper waveguide layer, an upper confinement layer and a protective layer, wherein the lower confinement layer and the upper confinement layer are made of Ga lattice-matched to the substrate. 1-z1 Al z1Sb material, the lower waveguide layer, the lower quantum barrier layer, the upper quantum barrier layer, and the upper waveguide layer are made of In lattice matching with the substrate. 1-x1-y1 Ga x1 Al y1 Sb material, quantum wells use In y Ga 1-y Sb material, where 0.20≤y≤0.60, and the protective layer is made of In x Ga 1-x Sb material.

[0027] Example 2

[0028] On the basis of Example 1, components or doping gradient layers are added between the functional layers, and the specific structure is as follows:

[0029] (1) In 0.10-0.50 Ga 0.50-0.90 Sb material is used as epitaxial substrate, the conductivity type is N-type, and the doping concentration is 2E17 to 2E18cm -3 ;

[0030] (2) Buffer layer: Material: In 0.10-0.50 Ga 0.50-0.90 Sb (same as substrate, homoepitaxial), N-type, doping concentration 8E17 to 2E18 cm -3 , thickness is 450-550nm;

[0031] (3) Lower confinement layer: material is Ga 1-z1 Al z1 Sb, lattice-matched to the substrate (e.g. In 0.10 Ga 0.90 Sb as substrate, z1 is 0.957), N-type, doping concentration is 4E17 to 1E18 cm -3 , thickness is 1600-2400 nm;

[0032] (4) There is a composition gradient layer between the buffer layer and the lower limiting layer, namely transition layer 1, N-type, with a doping concentration of 8E17 to 1E18 cm -3 , thickness is 20-40nm;

[0033] (5) Lower waveguide layer: material is In 1-x1-y1 Ga x1 Al y1 Sb, lattice-matched to the substrate (e.g. In 0.10 Ga 0.90 Sb as substrate, x1 is 0.386, y1 is 0.574), the width of the waveguide layer is 250-400nm;

[0034] (6) There is a composition gradient layer between the lower confinement layer and the lower waveguide layer, i.e., transition layer 2, with a thickness of 20-40 nm;

[0035] (7) Lower quantum barrier layer: material is In 1-x1-y1 Ga x1 Al y1 Sb, lattice-matched to the substrate (e.g. In 0.10 Ga 0.90 Sb as substrate, x1 is 0.386, y1 is 0.574), the barrier width is 16-30nm;

[0036] (8) Strain In 0.20-0.60 Ga 0.40-0.80 Sb is used as the quantum well in the active region, the thickness of the quantum well is 6-13nm, and the number of quantum wells is 1-3;

[0037] (9) Upper quantum barrier layer: material: In 1-x1-y1 Ga x1 Al y1 Sb, lattice-matched to the substrate (e.g. In 0.10 Ga 0.90 Sb as substrate, x1 is 0.386, y1 is 0.574), the barrier width is 16-30nm;

[0038] (10) Upper waveguide layer: material: In 1-x1-y1 Ga x1 Al y1 Sb, lattice-matched to the substrate (e.g. In 0.10 Ga 0.90 Sb as substrate, x1 is 0.386, y1 is 0.574), the width of the waveguide layer is 250-400nm;

[0039] (11) Upper confinement layer: material is Ga 1-z1 Al z1 Sb, lattice-matched to the substrate (e.g. In 0.10 Ga 0.90 Sb as substrate, z1 is 0.957), P-type, doping concentration is 5E18 to 3E19 cm -3 , thickness is 1600-2400nm;

[0040] (12) There is a composition gradient layer between the upper confinement layer and the upper waveguide layer, namely transition layer 3, which is P-type with a doping concentration of 5E18 to 3E19 cm -3 , thickness is 20-40nm;

[0041] (13) Protective layer: Material: In 0.10-0.50 Ga 0.50-0.90Sb, P-type, doping concentration 5E18 to 3E19 cm -3 , thickness is 150-250nm;

[0042] (14) There is a composition gradient layer between the upper limiting layer and the protective layer, namely transition layer 4, P type, with a doping concentration of 5E18 to 3E19 cm -3 , thickness is 20-40nm.

[0043] In with different In components x Ga 1-x Sb material is used as the substrate (x can be selected in the range of 0.05-0.65), and the components of each functional layer are changed accordingly to obtain a variety of pure antimonide strained quantum well lasers. The waveguide layer, confinement layer, and transition layer can have a small amount of strain.

[0044] The pure antimonide structure proposed by the present invention simplifies the epitaxial structure and reduces the difficulty of epitaxial growth. In addition, the band order of the structure is increased, the binding ability of carriers and light is enhanced, and the thermal conductivity is also increased.

[0045] 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 it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, 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 pure antimonide semiconductor laser, comprising a substrate, and a lower confinement layer, a lower waveguide layer, a lower quantum barrier layer, a quantum well, an upper quantum barrier layer, an upper waveguide layer, an upper confinement layer and a protective layer epitaxially grown in sequence on the substrate, characterized in that: The substrate and the protective layer are made of In x Ga 1-x Sb material, wherein 0.05≤x≤0.65, the lower limiting layer and the upper limiting layer are Ga lattice-matched with the substrate 1-z1 Al z1 Sb material, wherein 0.48≤z1≤0.98, the lower waveguide layer, the lower quantum barrier layer, the upper quantum barrier layer, and the upper waveguide layer are made of In lattice matching with the substrate. 1-x1-y1 Ga x1 Al y1 Sb material, wherein 0.17≤x1≤0.95, 0.02≤y1≤0.80, the quantum well is made of In y Ga 1-y Sb material, wherein 0.20≤y≤0.

60.

2. A pure antimonide semiconductor laser according to claim 1, characterized in that: A buffer layer is also arranged between the substrate and the lower limiting layer, and the buffer layer and the substrate are made of the same material.

3. A pure antimonide semiconductor laser according to claim 1, characterized in that: The barrier widths of the lower quantum barrier layer and the upper quantum barrier layer are both 16-30 nm.

4. A pure antimonide semiconductor laser according to claim 3, characterized in that: The thickness of the quantum well is 6-13 nm, and the number of the quantum wells is 1-3.

5. A pure antimonide semiconductor laser according to claim 2, characterized in that: The conductivity type of the substrate is N-type, and the doping concentration is 2E17 to 2E18 cm -3 The conductivity type of the buffer layer is N-type, and the doping concentration is 8E17 to 2E18cm -3 , thickness is 450-550nm.

6. The pure antimonide semiconductor laser according to claim 1, characterized in that: The conductivity type of the lower confinement layer is N-type, and the doping concentration is 4E17 to 1E18 cm -3 , thickness is 1600-2400nm; The conductivity type of the upper confinement layer is P type, and the doping concentration is 5E18 to 3E19 cm -3 , thickness is 1600-2400nm.

7. A pure antimonide semiconductor laser according to claim 2, characterized in that: There is a composition gradient layer between the buffer layer and the lower limiting layer, namely the first transition layer. The conductivity type of the first transition layer is N type, and the doping concentration is 8E17 to 1E18cm -3 , thickness is 20-40nm.

8. The pure antimonide semiconductor laser according to claim 7, characterized in that: There is a composition gradient layer between the lower limiting layer and the lower waveguide layer, namely the second transition layer, with a thickness of 20-40 nm.

9. A pure antimonide semiconductor laser according to claim 8, characterized in that: There is a composition gradient layer between the upper limiting layer and the upper waveguide layer, i.e., the third transition layer. The conductivity type of the third transition layer is P type, and the doping concentration is 5E18 to 3E19 cm -3 , thickness is 20-40nm.

10. The pure antimonide semiconductor laser according to claim 9, characterized in that: There is a composition gradient layer between the upper limiting layer and the protective layer, i.e., the fourth transition layer. The conductivity type of the fourth transition layer is P type, and the doping concentration is 5E18 to 3E19 cm -3 , thickness is 20-40nm.

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