GaN-based semiconductor laser with mode selection lower waveguide layer

Abstract

The invention discloses a GaN-based semiconductor laser with a mode selection lower waveguide layer, which sequentially comprises a substrate, a lower coating layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer, an upper coating layer and a contact layer from bottom to top, and is characterized in that the lower waveguide layer is the mode selection lower waveguide layer; the mode selection lower waveguide layer comprises a first mode selection lower waveguide layer and a second mode selection lower waveguide layer; and the thickness of the waveguide layer under mode selection is 5-1000 nm. According to the invention, valence band effective state density and distribution of an electric field in the lower waveguide layer are regulated and controlled, distribution, dissipation and mode selection of a light field are controlled, a light field mode is prevented from leaking to a substrate to form a standing wave, a far-field image approaches a Gaussian distribution pattern, light spot quality and far-field beam quality are improved, and a horizontal divergence angle is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor optoelectronic devices, and in particular to a GaN-based semiconductor laser with a mode-selective lower waveguide layer. Background Art

[0002] Lasers are widely used in laser display, laser TV, laser projector, communication, medical treatment, weapons, guidance, ranging, spectral analysis, cutting, precision welding, high-density optical storage and other fields. There are many types of lasers, and the classification methods are also diverse, mainly including solid, gas, liquid, semiconductor and dye types of lasers; compared with other types of lasers, all-solid-state semiconductor ultraviolet lasers have the advantages of small size, high efficiency, light weight, good stability, long life, simple and compact structure, and miniaturization.

[0003] There are significant differences between lasers and nitride semiconductor light-emitting diodes. 1) Lasers are generated by stimulated radiation from carriers, with a small half-width spectrum and high brightness. The output power of a single laser can be in the W level, while nitride semiconductor light-emitting diodes emit spontaneous radiation, and the output power of a single light-emitting diode is in the mW level. 2) The current density of the laser is as high as KA / cm 2 , which is more than 2 orders of magnitude higher than that of nitride light-emitting diodes, resulting in stronger electron leakage, more serious Auger recombination, stronger polarization effect, more serious electron-hole mismatch, and more serious efficiency attenuation Droop effect; 3) The light-emitting diode spontaneously radiates, without external influence, and is incoherent light that transitions from high energy level to low energy level, while the laser is stimulated transition radiation, and the energy of the induced photon should be equal to the difference in energy levels of the electron transition, generating photons and induced photons with identical coherent light; 4) The principles are different: the light-emitting diode is under the action of external voltage, and the electron-hole transition to the active layer or pn junction generates radiation recombination and luminescence, while the laser needs the lasing conditions to be met before it can be lased, and the carrier inversion distribution in the active area must be met. The stimulated radiation light oscillates back and forth in the resonant cavity, and the propagation in the gain medium amplifies the light, and the threshold condition is met so that the gain is greater than the loss, and finally the laser is output.

[0004] Nitride semiconductor ultraviolet lasers have the following problems: the light field is dissipated, and the light field mode leaks to the substrate to form standing waves, which leads to low substrate mode suppression efficiency and poor far-field image FFP quality. The laser light wave can be divided into transverse mode and longitudinal mode; the transverse mode intensity distribution in the cross section perpendicular to the optical axis is determined by the waveguide structure of the semiconductor laser. If the transverse mode is complex and unstable, the coherence of the output light is poor; the longitudinal mode is a standing wave distribution in the propagation direction of the resonant cavity. If many longitudinal modes are simultaneously emitted or there are inter-mode changes, high temporal coherence cannot be obtained, and the far-field image FFP quality is poor. Summary of the invention

[0005] The present invention proposes a GaN-based semiconductor laser with a mode-selective lower waveguide layer, which regulates the distribution of the valence band effective state density and the electric field in the lower waveguide layer, controls the distribution, dissipation and mode selection of the light field, suppresses the leakage of the light field mode to the substrate to form a standing wave, makes the far-field image approach a Gaussian distribution pattern, improves the light spot quality and the far-field beam quality, and reduces the horizontal divergence angle.

[0006] The present invention provides a GaN-based semiconductor laser with a mode-selective lower waveguide layer, which comprises, from bottom to top, a substrate, a lower cladding layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer, an upper cladding layer and a contact layer, wherein the lower waveguide layer is a mode-selective lower waveguide layer; the mode-selective lower waveguide layer comprises a first mode-selective lower waveguide layer and a second mode-selective lower waveguide layer; the mode-selective lower waveguide layer is any one or any combination of InGaN, GaN, InN, AlInGaN, AlInN, AlN, InGaN / GaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, InGaN / AlInN superlattice, GaN / AlGaN superlattice, GaN / AlInGaN superlattice and GaN / AlN superlattice, and has a thickness of 5 to 1000 nm.

[0007] Preferably, the first mode is selected so that the rising angle of the valley position of the peak rate electric field of the waveguide layer toward the lower cladding layer is α, the rising angle of the valley position of the valence band effective state density of the waveguide layer toward the lower cladding layer is β, the descending angle of the peak position of the radiation recombination coefficient of the waveguide layer toward the lower cladding layer is γ, and the descending angle of the peak position of the density of the waveguide layer toward the lower cladding layer is θ, wherein: 45°≤θ≤γ≤α≤β≤90°.

[0008] Preferably, the second mode is selected so that the rising angle of the valley position of the peak rate electric field of the waveguide layer toward the lower cladding layer is δ, the descending angle of the peak position of the valence band effective state density of the waveguide layer toward the lower cladding layer is σ, the descending angle of the peak position of the radiation recombination coefficient of the waveguide layer toward the lower cladding layer is φ, and the descending angle of the peak position of the density of the waveguide layer toward the lower cladding layer is ψ, wherein: 40°≤φ≤ψ≤σ≤δ≤90°.

[0009] Preferably, the descending angle of the peak position of the peak rate electric field of the waveguide layer under the first mode selection toward the active layer is μ, the rising angle of the valley position of the valence band effective state density of the waveguide layer under the first mode selection toward the active layer is ρ, the rising angle of the valley position of the radiation recombination coefficient of the waveguide layer under the first mode selection toward the active layer is ω, and the rising angle of the valley position of the density of the waveguide layer under the first mode selection toward the active layer is ε, wherein: 35°≤ω≤ε≤ρ≤μ≤90°.

[0010] Preferably, the first mode selects the rising angle of the valley position of the peak rate electric field and the valence band effective state density of the lower waveguide layer toward the lower cladding layer, the first mode selects the descending angle of the peak position of the radiation recombination coefficient and the density of the lower waveguide layer toward the lower cladding layer, the second mode selects the rising angle of the valley position of the peak rate electric field of the lower waveguide layer toward the lower cladding layer, the second mode selects the descending angle of the peak position of the valence band effective state density, the radiation recombination coefficient and the density of the lower waveguide layer toward the lower cladding layer, the first mode selects the descending angle of the peak position of the peak rate electric field of the lower waveguide layer toward the active layer, and the first mode selects the rising angle of the valley position of the valence band effective state density, the radiation recombination coefficient and the density of the lower waveguide layer toward the active layer. 35°≤ω≤ε≤ρ≤μ≤φ≤ψ≤σ≤δ≤θ≤γ≤α≤β≤90°.

[0011] Preferably, the peak velocity electric field distribution of the first mode selective waveguide layer has a function y=lnx / e x curve distribution; the valence band effective state density distribution of the waveguide layer under the first mode selection has a function y=lnx / x curve distribution; the radiation recombination coefficient distribution of the waveguide layer under the first mode selection has a function y=x / lnx first quadrant curve distribution; the density distribution of the waveguide layer under the first mode selection has a function y=(e x +e -x ) / (e x -e -x )The first quadrant curve distribution.

[0012] Preferably, the peak velocity electric field distribution of the second mode selective waveguide layer has a function y=e x / x 2 curve distribution; the second mode selection waveguide layer valence band effective state density distribution has a function y = x / lnx fourth quadrant curve distribution; the second mode selection waveguide layer radiation recombination coefficient distribution has a function y = e x / x third quadrant curve distribution; the density distribution of the waveguide layer under the second mode selection has a function y=(e x +e -x ) / (ex -e -x )The third quadrant curve distribution.

[0013] Preferably, the active layer and the upper waveguide layer are any one or any combination of InGaN, GaN, AlInGaN, AlN, AlInN, and AlGaN; the lower cladding layer and the upper cladding layer are any one or any combination of GaN, AlInGaN, AlN, AlInN, and AlGaN; the thickness of the lower confinement layer is 50 to 90,000 angstroms; the electron blocking layer and the contact layer are InGaN, InN, GaN, AlInGaN, AlN, AlInN, AlGaN, SiC, Ga 2 O 3 , BN, diamond or any combination thereof, and the thickness of the lower limiting layer is 5 to 2000 angstroms.

[0014] Preferably, the substrate comprises sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, sapphire / SiO 2 Composite substrate, diamond, sapphire / AlN composite substrate, sapphire / SiN x 、MgAl spinel 2 O 4 、MgO、ZnO、ZrB 2 、LiAlO 2 and LiGaO 2 Any type of composite substrate.

[0015] Compared with the prior art, the GaN-based semiconductor laser with a mode-selective lower waveguide layer provided in an embodiment of the present invention has the following beneficial effects: the present invention designs the change angle and change curve of the peak rate electric field and the valence band effective state density of the mode-selective lower waveguide layer, regulates the distribution of the valence band effective state density and the electric field in the lower waveguide layer, controls the distribution, dissipation and mode selection of the light field, suppresses the leakage of the light field mode to the substrate to form a standing wave, makes the far-field image approach a Gaussian distribution pattern, improves the light spot quality and the far-field beam quality, and reduces the horizontal divergence angle; at the same time, the present invention designs the change angle and change curve of the radiation recombination coefficient and density of the mode-selective lower waveguide layer, regulates the energy band distribution and mode selection of the laser lower waveguide layer, stabilizes the transverse mode, improves the laser coherence, reduces the inter-mode variation of the longitudinal mode, and improves the temporal coherence and far-field image quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 1 is a schematic structural diagram of a GaN-based semiconductor laser having a mode-selective lower waveguide layer according to an embodiment of the present invention;

[0017] Figure 2This is a structural SIMS secondary ion mass spectrum of a GaN-based semiconductor laser with a mode-selective lower waveguide layer according to an embodiment of the present invention;

[0018] Figure 3 This is a structural SIMS secondary ion mass spectrum of a GaN-based semiconductor laser with a mode-selective lower waveguide layer according to an embodiment of the present invention (partially enlarged view);

[0019] Figure 4 This is a TEM lens electron microscope image of a GaN-based semiconductor laser with a mode-selective lower waveguide layer according to an embodiment of the present invention;

[0020] Figure 5 This is a TEM lens electron microscope image (partial magnified image) of a GaN-based semiconductor laser with a mode-selective lower waveguide layer according to an embodiment of the present invention;

[0021] Figure 6 This is a TEM lens electron microscope image (partial magnified image) of a GaN-based semiconductor laser with a mode-selective lower waveguide layer according to an embodiment of the present invention;

[0022] Reference numerals: 100: substrate; 101: lower cladding layer; 102: lower waveguide layer; 102a: first mode selective lower waveguide layer; 102b: second mode selective lower waveguide layer; 103: active layer; 104: upper waveguide layer, 105: electron blocking layer, 106: upper cladding layer, 107: contact layer. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0024] In order to solve the above problems, a GaN-based semiconductor laser with a mode-selective lower waveguide layer provided in an embodiment of the present application will be introduced and explained in detail through the following specific embodiments.

[0025] Reference Figure 1-6The present invention provides a GaN-based semiconductor laser with a mode-selective lower waveguide layer, which includes, from bottom to top, a substrate 100, a lower cladding layer 101, a lower waveguide layer 102, an active layer 103, an upper waveguide layer 104, an electron blocking layer 105, an upper cladding layer 106 and a contact layer 107, wherein the lower waveguide layer 102 is a mode-selective lower waveguide layer; the mode-selective lower waveguide layer 102 includes a first mode-selective lower waveguide layer 102a and a second mode-selective lower waveguide layer 102b; The mode-selective lower waveguide layer is any one or any combination of InGaN, GaN, InN, AlInGaN, AlInN, AlN, InGaN / GaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, InGaN / AlInN superlattice, GaN / AlGaN superlattice, GaN / AlInGaN superlattice, and GaN / AlN superlattice, and has a thickness of 5 to 1000 nm.

[0026] In the present invention, Figure 2-3 As shown, the first mode selects that the valley position of the peak rate electric field of the waveguide layer 102a rises at an angle α toward the lower cladding layer 101, the first mode selects that the valley position of the valence band effective state density of the waveguide layer 102a rises at an angle β toward the lower cladding layer 101, the first mode selects that the peak position of the radiation recombination coefficient of the waveguide layer 102a falls at an angle γ toward the lower cladding layer 101, and the first mode selects that the peak position of the density of the waveguide layer 102a falls at an angle θ toward the lower cladding layer 101, wherein: 45°≤θ≤γ≤α≤β≤90°.

[0027] In the present invention, the second mode selects that the valley position of the peak rate electric field of the lower waveguide layer 102b rises at an angle of δ toward the lower cladding layer 101, the second mode selects that the peak position of the valence band effective state density of the lower waveguide layer 102b falls at an angle of σ toward the lower cladding layer 101, the second mode selects that the peak position of the radiation recombination coefficient of the lower waveguide layer 102b falls at an angle of φ toward the lower cladding layer 101, and the second mode selects that the peak position of the density of the lower waveguide layer 102b falls at an angle of ψ toward the lower cladding layer 101, wherein: 40°≤φ≤ψ≤σ≤δ≤90°.

[0028] In the present invention, the descending angle of the peak position of the peak rate electric field of the waveguide layer 102a in the first mode selection toward the active layer 103 is μ, the rising angle of the valley position of the valence band effective state density of the waveguide layer 102a in the first mode selection toward the active layer 103 is ρ, the rising angle of the valley position of the radiation recombination coefficient of the waveguide layer 102a in the first mode selection toward the active layer 103 is ω, and the rising angle of the valley position of the density of the waveguide layer 102a in the first mode selection toward the active layer 103 is ε, wherein: 35°≤ω≤ε≤ρ≤μ≤90°.

[0029] In the present invention, the first mode selects the rising angle of the valley position of the peak rate electric field and the valence band effective state density of the lower waveguide layer 102a toward the lower cladding layer 101, the first mode selects the descending angle of the peak position of the radiation recombination coefficient and density of the lower waveguide layer 102a toward the lower cladding layer 101, the second mode selects the rising angle of the valley position of the peak rate electric field of the lower waveguide layer 102b toward the lower cladding layer 101, the second mode selects the valence band effective state density of the lower waveguide layer 102b. The descending angle of the peak position of the state density, radiation recombination coefficient, and density toward the lower cladding layer 101, the descending angle of the peak position of the peak rate electric field of the lower waveguide layer 102a selected by the first mode toward the active layer 103, and the rising angle of the valley position of the valence band effective state density, radiation recombination coefficient, and density of the lower waveguide layer 102a selected by the first mode toward the active layer 103 have the following relationship: 35°≤ω≤ε≤ρ≤μ≤φ≤ψ≤σ≤δ≤θ≤γ≤α≤β≤90°.

[0030] In the present invention, the peak rate electric field distribution of the waveguide layer 102a under the first mode selection has a function y=lnx / e x curve distribution; the valence band effective state density distribution of the waveguide layer 102a under the first mode selection has a function y=lnx / x curve distribution; the radiation recombination coefficient distribution of the waveguide layer 102a under the first mode selection has a function y=x / lnx first quadrant curve distribution; the density distribution of the waveguide layer 102a under the first mode selection has a function y=e x +e -x / (e x -e -x )The first quadrant curve distribution.

[0031] In the present invention, the peak rate electric field distribution of the waveguide layer 102b in the second mode selection has a function y=e x / x 2curve distribution; the second mode selection waveguide layer 102b valence band effective state density distribution has a function y = x / lnx fourth quadrant curve distribution; the second mode selection waveguide layer 102b radiation recombination coefficient distribution has a function y = e x / x third quadrant curve distribution; the density distribution of the waveguide layer 102b under the second mode selection has a function y=e x +e -x / (e x -e -x )The third quadrant curve distribution.

[0032] In summary, if Figure 4-6 As shown, the present invention regulates the distribution of the valence band effective state density and the electric field in the lower waveguide layer, controls the distribution, dissipation and mode selection of the light field, suppresses the leakage of the light field mode to the substrate to form a standing wave, makes the far-field image approach a Gaussian distribution pattern, improves the spot quality and the far-field beam quality, and reduces the horizontal divergence angle; secondly, the present invention designs the change angle and change curve of the radiation recombination coefficient and density of the lower waveguide layer of the mode selection, regulates the energy band distribution and mode selection of the laser lower waveguide layer 102, stabilizes the transverse mode, improves the laser coherence, reduces the inter-mode variation of the longitudinal mode, and improves the temporal coherence and far-field image quality.

[0033] In the present invention, the active layer 103 and the upper waveguide layer 104 are any one or any combination of InGaN, GaN, AlInGaN, AlN, AlInN, and AlGaN; the lower cladding layer 101 and the upper cladding layer 106 are any one or any combination of GaN, AlInGaN, AlN, AlInN, and AlGaN, and the thickness of the lower confinement layer is 50 to 90,000 angstroms; the electron blocking layer 105 and the contact layer 107 are InGaN, InN, GaN, AlInGaN, AlN, AlInN, AlGaN, SiC, Ga 2 O 3 , BN, diamond or any combination thereof, and the thickness of the lower limiting layer is 5 to 2000 angstroms.

[0034] In the present invention, the substrate 100 includes sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, sapphire / SiO 2 Composite substrate, diamond, sapphire / AlN composite substrate, sapphire / SiN x 、MgAl spinel 2 O 4 、MgO、ZnO、ZrB 2 、LiAlO 2 and LiGaO 2 Any type of composite substrate.

[0035] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A GaN-based semiconductor laser having a mode-selective lower waveguide layer, comprising, from bottom to top, a substrate (100), a lower cladding layer (101), a lower waveguide layer (102), an active layer (103), an upper waveguide layer (104), an electron blocking layer (105), an upper cladding layer (106) and a contact layer (107), characterized in that: The lower waveguide layer (102) is a mode selection lower waveguide layer; the mode selection lower waveguide layer (102) comprises a first mode selection lower waveguide layer (102a) and a second mode selection lower waveguide layer (102b); the mode selection lower waveguide layer is any one or any combination of InGaN, GaN, InN, AlInGaN, AlInN, AlN, InGaN / GaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, InGaN / AlInN superlattice, GaN / AlGaN superlattice, GaN / AlInGaN superlattice, and GaN / AlN superlattice, and has a thickness of 5 to 1000 nm.

2. A GaN-based semiconductor laser with a mode-selective lower waveguide layer according to claim 1, characterized in that: The first mode is selected such that the valley position of the peak rate electric field of the waveguide layer (102a) rises at an angle α toward the lower cladding layer (101), the valley position of the valence band effective state density of the waveguide layer (102a) rises at an angle β toward the lower cladding layer (101), the peak position of the radiation recombination coefficient of the waveguide layer (102a) falls at an angle γ toward the lower cladding layer (101), and the peak position of the density of the waveguide layer (102a) falls at an angle θ toward the lower cladding layer (101), wherein: 45°≤θ≤γ≤α≤β≤90°.

3. A GaN-based semiconductor laser with a mode-selective lower waveguide layer according to claim 1, characterized in that: The second mode is selected such that the rising angle of the valley position of the peak rate electric field of the lower waveguide layer (102b) toward the lower cladding layer (101) is δ, the falling angle of the peak position of the valence band effective state density of the lower waveguide layer (102b) toward the lower cladding layer (101) is σ, the falling angle of the peak position of the radiation recombination coefficient of the lower waveguide layer (102b) toward the lower cladding layer (101) is φ, and the falling angle of the peak position of the density of the lower waveguide layer (102b) toward the lower cladding layer (101) is ψ, wherein: 40°≤φ≤ψ≤σ≤δ≤90°.

4. The GaN-based semiconductor laser with a mode-selective lower waveguide layer according to claim 1, characterized in that: The first mode selection has a descending angle of μ at the peak position of the peak rate electric field of the waveguide layer (102a) toward the active layer (103), a rising angle of ρ at the valley position of the valence band effective state density of the waveguide layer (102a) toward the active layer (103), a rising angle of ω at the valley position of the radiation recombination coefficient of the waveguide layer (102a) toward the active layer (103), and a rising angle of ε at the valley position of the density of the waveguide layer (102a) toward the active layer (103), wherein: 35°≤ω≤ε≤ρ≤μ≤90°.

5. A GaN-based semiconductor laser with a mode-selective lower waveguide layer according to claim 2, 3 or 4, characterized in that: The first mode selects the rising angle of the valley position of the peak rate electric field and the valence band effective state density of the lower waveguide layer (102a) toward the lower cladding layer (101), the first mode selects the falling angle of the peak position of the radiation recombination coefficient and density of the lower waveguide layer (102a) toward the lower cladding layer (101), the second mode selects the rising angle of the valley position of the peak rate electric field of the lower waveguide layer (102b) toward the lower cladding layer (101), the second mode selects the rising angle of the valley position of the valence band effective state density of the lower waveguide layer (102b) The density, the radiation recombination coefficient, and the descending angle of the peak position of the density toward the lower cladding layer (101), the descending angle of the peak position of the peak rate electric field of the waveguide layer (102a) selected by the first mode toward the active layer (103), and the rising angle of the valence band effective state density, the radiation recombination coefficient, and the valley position of the density of the waveguide layer (102a) selected by the first mode toward the active layer (103) have the following relationship: 35°≤ω≤ε≤ρ≤μ≤φ≤ψ≤σ≤δ≤θ≤γ≤α≤β≤90°.

6. The GaN-based semiconductor laser with a mode-selective lower waveguide layer according to claim 1, characterized in that: The peak velocity electric field distribution of the waveguide layer (102a) under the first mode selection has a function y=lnx / e x curve distribution; the valence band effective state density distribution of the waveguide layer (102a) under the first mode selection has a function y=lnx / x curve distribution; the radiation recombination coefficient distribution of the waveguide layer (102a) under the first mode selection has a function y=x / lnx first quadrant curve distribution; the density distribution of the waveguide layer (102a) under the first mode selection has a function y=(e x +e -x ) / (e x -e -x )The first quadrant curve distribution.

7. The GaN-based semiconductor laser with a mode-selective lower waveguide layer according to claim 1, characterized in that: The peak velocity electric field distribution of the second mode selective waveguide layer (102b) has a function y=e x / x 2 curve distribution; the valence band effective state density distribution of the waveguide layer (102b) under the second mode selection has a function y=x / lnx fourth quadrant curve distribution; the radiation recombination coefficient distribution of the waveguide layer (102b) under the second mode selection has a function y=e x / x third quadrant curve distribution; the density distribution of the waveguide layer (102b) under the second mode selection has a function y=(e x +e -x ) / (e x -e -x )The third quadrant curve distribution.

8. The GaN-based semiconductor laser with a mode-selective lower waveguide layer according to claim 1, characterized in that: The active layer (103) and the upper waveguide layer (104) are any one or any combination of InGaN, GaN, AlInGaN, AlN, AlInN, and AlGaN; the lower cladding layer (101) and the upper cladding layer (106) are any one or any combination of GaN, AlInGaN, AlN, AlInN, and AlGaN, and the thickness of the lower limiting layer is 50 to 90,000 angstroms; the electron blocking layer (105) and the contact layer (107) are any one or any combination of InGaN, InN, GaN, AlInGaN, AlN, AlInN, AlGaN, SiC, Ga2O3, BN, and diamond, and the thickness of the lower limiting layer is 5 to 2,000 angstroms.

9. The GaN-based semiconductor laser with a mode-selective lower waveguide layer according to claim 1, characterized in that: The substrate (100) includes sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, sapphire / SiO2 composite substrate, diamond, sapphire / AlN composite substrate, sapphire / SiN x , any one of magnesia-aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrates.

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