Nitride semiconductor laser

Abstract

The invention provides a nitride semiconductor laser. The laser comprises a substrate, a lower coating layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer and an upper coating layer which are sequentially arranged from bottom to top. And the lower waveguide layer comprises any one or a combination of more of InGaN, GaN, InN, AlInGaN, an InGaN / GaN superlattice, an InGaN / AlGaN superlattice, an InGaN / AlGaN superlattice, an InGaN / AlInN superlattice and an InGaN / AlInGaN superlattice. The peak rate electric field distribution of the lower waveguide layer has an arc distribution, and the peak rate electric field distribution has a curve distribution of a function y = logax (a > 1). The drift rate distribution of the saturated electrons of the lower waveguide layer has an arc-shaped distribution, and the drift rate distribution of the saturated electrons has a curve distribution of a third quadrant of a function y = x-b (b > 1, b is an odd number). The density distribution of valence band effective states of the lower waveguide layer has a curve distribution of a third quadrant of a function y = (cx + 1) / (cx-1) (c > 1).

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor optoelectronic devices, and particularly to a nitride semiconductor laser. BACKGROUND

[0002] Lasers are widely used in laser display, laser television, laser projector, communication, medical treatment, weapon, guidance, distance measurement, spectrum analysis, cutting, precision welding, high-density optical storage and other fields. There are many types of lasers, and the classification methods are also various. The main types include solid, gas, liquid, semiconductor and dye, etc. Compared with other types of lasers, all-solid-state semiconductor lasers have the advantages of small size, high efficiency, light weight, good stability, long service life, simple and compact structure, and small size.

[0003] There are great differences between lasers and nitride semiconductor light-emitting diodes: 1) Laser is generated by stimulated radiation of carriers, with small spectral half-width and high brightness. The output power of a single laser can reach W level, while the output power of a single nitride semiconductor light-emitting diode is in mW level; 2) The current density of laser is up to KA / cm 2 , which is more than 2 orders of magnitude higher than that of nitride light-emitting diode, resulting in stronger electron leakage, more serious Auger recombination, stronger polarization effect and more serious electron-hole mismatch, leading to more serious efficiency droop effect; 3) Nitride light-emitting diode is spontaneously transitioned and radiated, with incoherent light from high energy level to low energy level without external action, while laser is stimulated transition and radiation, with coherent light of the same phase of generated photons and induced photons; 4) Different principles: nitride light-emitting diode is under the action of external voltage, and electron-hole transition occurs in quantum well or p-n junction to produce radiation recombination and light emission, while laser needs to meet the lasing conditions, and the carrier inversion distribution in the active region, the back-and-forth oscillation of stimulated radiation light in the resonant cavity, the propagation of light in the gain medium to make light amplification, and the threshold condition to make the gain greater than the loss, and finally output laser.

[0004] The nitride semiconductor laser has the following problems: the refractive index dispersion of the laser, the fluctuation of high-concentration carrier concentration affecting the refractive index of the active layer, and the decrease of the limitation factor with the increase of the wavelength, resulting in the decrease of the mode gain of the laser. SUMMARY

[0005] The present application provides a nitride semiconductor laser, 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, and an upper cladding layer. The lower waveguide layer is a refractive index gradient lower waveguide layer, the refractive index of the lower waveguide layer decreases, and the trend curve of the decrease has a function y=C1+D1*x -d1a curve distribution in the third quadrant of the function f(d1), where d1 is an odd number and d1 > 1. BRIEF DESCRIPTION OF DRAWINGS

[0006] The description includes drawings to provide further understanding of the embodiments and the drawings are incorporated in and constitute a part of the specification. The drawings illustrate the embodiments and serve to explain the principles of the present invention. Other embodiments and many of the intended advantages of the embodiments will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings. The detailed description, which makes reference to the drawings, is better understood when taken in connection with the accompanying drawings, as follows:

[0007] Figure 1 is a structure schematic diagram of a nitride semiconductor laser according to an embodiment of the present specification;

[0008] Figure 2 is a secondary ion mass spectroscopy (SIMS) diagram of a structure of a nitride semiconductor laser according to some embodiments of the present specification;

[0009] Figure 3 is a SIMS diagram of a nitride semiconductor laser according to another embodiment of the present specification;

[0010] Figure 4 is a TEM diagram of an upper cladding layer of a nitride semiconductor laser according to an embodiment of the present specification at a scale of 100 nm;

[0011] Figure 5 is a TEM diagram of an upper waveguide layer of a nitride semiconductor laser according to an embodiment of the present specification at a scale of 100 nm;

[0012] Figure 6 is a TEM diagram of an active layer of a nitride semiconductor laser according to an embodiment of the present specification at a scale of 10 nm;

[0013] Figure 7 is a TEM diagram of a lower waveguide layer of a nitride semiconductor laser according to an embodiment of the present specification at a scale of 200 nm;

[0014] Figure 8 is a TEM diagram of an electron blocking layer of a nitride semiconductor laser according to an embodiment of the present specification at a scale of 20 nm;

[0015] Figure 9 is a structure SIMS diagram of a nitride semiconductor laser according to another embodiment of the present specification;

[0016] Figure 10 is a SIMS diagram of a graded polarization layer of a nitride semiconductor laser according to an embodiment of the present specification;

[0017] Figure 11 is a partial enlarged view of a SIMS diagram of a graded polarization layer of a nitride semiconductor laser according to an embodiment of the present specification;

[0018] Figure 12 is a SIMS diagram of a strong coherent quantum well of a nitride semiconductor laser according to an embodiment of the present specification;

[0019] Figure 13 is a SIMS diagram of a strong coherent quantum well of a nitride semiconductor laser according to an embodiment of the present specification.

[0020] The meanings of the respective numbers in the drawings are as follows: 100 - substrate; 101 - lower cladding layer; 102 - lower waveguide layer; 103 - active layer; 104 - upper waveguide layer; 105 - electron blocking layer; 106 - upper cladding layer; 107 - graded polarization layer. DETAILED DESCRIPTION

[0021] The present application will be further described below in conjunction with the drawings and embodiments. It can be understood that the specific embodiments described herein are merely intended for explaining the related application, and are not a limitation on the application. In addition, it should be noted that only the parts related to the application are shown in the drawings for the convenience of description.

[0022] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0023] Figure 1 is a structural schematic diagram of a nitride semiconductor laser according to an embodiment of the present specification.

[0024] As shown in Figure 1 , the nitride semiconductor laser can include, 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, and an upper cladding layer 106.

[0025] The substrate 100 is a base layer in a semiconductor laser for providing electronic and optical properties and carrying functional layers. In some embodiments, the substrate 100 includes any one of sapphire, silicon (Si), germanium (Ge), silicon carbide (SiC), aluminum nitride (AIN), gallium nitride (GaN), gallium arsenide (GaAs), indium phosphide (InP), indium arsenide (InAs), gallium antimonide (GaSb), sapphire / silicon dioxide (Si02) composite substrate, molybdenum (Mo), titanium tungsten alloy (TiW), copper tungsten alloy (CuW), copper (Cu), sapphire / AIN composite substrate, diamond, sapphire / Si02 / SiN x composite substrate, sapphire / SiN x composite substrate, sapphire / SiN x / Si02 composite substrate, magnesium aluminum spinel (MgAl204), magnesium oxide (MgO), zinc oxide (ZnO), zirconium diboride (ZrB2), lithium aluminate (LiA102), and lithium gallate (LiGa02) composite substrate, etc.

[0026] The lower cladding layer 101 and the upper cladding layer 106 can be used to support and protect the structural layers in the middle of the semiconductor laser, such as the lower waveguide layer 102, the active layer 103, the upper waveguide layer 104, etc.

[0027] In some embodiments, the material of the lower cladding layer 101 and / or the upper cladding layer 106 includes a nitride semiconductor, an arsenide semiconductor, an indium-based semiconductor, an antimony compound semiconductor, or other semiconductors.

[0028] In some embodiments, the lower cladding layer 101 and / or the upper cladding layer 106 includes any one or a combination of gallium nitride (GaN), indium gallium nitride (InGaN), indium nitride (InN), aluminum indium nitride (AlInN), aluminum gallium nitride (AlGaN), aluminum indium gallium nitride (AlInGaN), aluminum nitride (AIN), gallium arsenide (GaAs), gallium phosphide (GaP), indium phosphide (InP), aluminum gallium arsenide (AlGaAs), aluminum indium gallium arsenide (AlInGaAs), aluminum gallium indium phosphide (AlGaInP), indium gallium arsenide (InGaAs), indium gallium arsenide nitride (InGaAsN), aluminum indium arsenide (AlInAs), aluminum indium phosphide (AlInP), aluminum gallium phosphide (AlGaP), indium gallium phosphide (InGaP), gallium antimonide (GaSb), indium antimonide (InSb), indium arsenide (InAs), indium arsenic antimonide (InAsSb), aluminum gallium antimonide (AlGaSb), aluminum antimonide (AlSb), indium gallium antimonide (InGaSb), aluminum gallium arsenic antimonide (AlGaAsSb), indium gallium arsenic antimonide (InGaAsSb), silicon carbide (SiC), silicon oxide (Ga203), boron nitride (BN), and diamond, etc.

[0029] The waveguide layers (e.g., the lower waveguide layer 102 and the upper waveguide layer 104) can be used to effectively guide the light waves and reduce the light wave propagation loss of the semiconductor laser.

[0030] In some embodiments, the lower waveguide layer 102 is a graded-index lower waveguide layer. In some embodiments, the refractive index of the lower waveguide layer 102 decreases. That is, the refractive index of the lower waveguide layer 102 is graded in a decreasing manner.

[0031] In some embodiments, the trend curve of the refractive index decrease of the lower waveguide layer 102 has a curve distribution of a first objective function. In some embodiments, the trend curve of the refractive index decrease of the lower waveguide layer 102 has a curve distribution of the third quadrant of the function y = C1 + D1 * x -d1 , where d1 is an odd number and d1 > 1; C1 and D1 are constants.

[0032] By forming the graded-index lower waveguide layer, the carriers and photons can be effectively confined within the active region, the longitudinal diffusion of the light field can be controlled, and the carriers can be aggregated, so that the confinement factor, the carrier injection efficiency, and the carrier injection uniformity of the laser are improved, and thus the mode gain and the light emission power of the semiconductor laser are improved, and the threshold current is reduced.

[0033] The semiconductor laser provided in the embodiments of the present specification can achieve the following effects: Blue laser - project Conventional laser Invention laser Variation amplitude Limiting factor 1.50％ 2.91％ 94％ Slope efficiency (W / A) 0.8 1.84 130％ Optical power (W) 4.6 6.7 46％

[0034] In some embodiments, the material of the lower waveguide layer 102 can be a single-crystal semiconductor or a superlattice semiconductor. In some embodiments, the lower waveguide layer 102 includes any one or a combination of multiple of InGaN, GaN, InN, AlInGaN, InGaN / GaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInN superlattice, InGaN / AlInGaN superlattice, and the like.

[0035] In some embodiments, the peak rate electric field distribution of the lower waveguide layer 102 has an arc-shaped distribution.

[0036] In some embodiments, the peak rate electric field distribution of the lower waveguide layer 102 has a curve distribution of a second objective function. In some embodiments, the peak rate electric field distribution of the lower waveguide layer 102 has a curve distribution of the function y = log a1 x, where a1 > 1.

[0037] In some embodiments, the saturated drift velocity distribution of the lower waveguide layer 102 has an arc-shaped distribution.

[0038] In some embodiments, the drift velocity distribution of the saturated electrons of the lower waveguide layer 102 has a curve distribution of a third target function. In some embodiments, the drift velocity distribution of the saturated electrons of the lower waveguide layer 102 has a curve distribution of the third quadrant of a function y = E1 + F1 * x -b1 , where b1 is an odd number and b1 > 1; E1 and F1 are constants.

[0039] In some embodiments, the density distribution of the effective states in the valence band of the lower waveguide layer 102 has a curve distribution of a fourth target function. The density of the effective states in the valence band refers to the number of electron states per unit energy range that can be occupied in the valence band.

[0040] In some embodiments, the density distribution of the effective states in the valence band of the lower waveguide layer 102 has a curve distribution of the third quadrant of a function y = G1 + H1 * (c1 x + 1) / (c1 x - 1), where c1 > 1; G1 and H1 are constants.

[0041] In some embodiments, the longitudinal sound velocity distribution of the lower waveguide layer 102 has a curve distribution of a fifth target function. In some embodiments, the longitudinal sound velocity distribution of the lower waveguide layer 102 has a curve distribution of the second quadrant of a function y = A1 + B1 * e x / x 2 , where A1 and B1 are constants.

[0042] In some embodiments, the peak velocity electric field distribution, the drift velocity distribution of the saturated electrons, and the density distribution of the effective states in the valence band of the lower waveguide layer 102 satisfy a first preset condition. In some embodiments, the peak velocity electric field distribution, the drift velocity distribution of the saturated electrons, and the density distribution of the effective states in the valence band of the lower waveguide layer 102 have the following relationship: 1 < c1 ≤ b1 ≤ a1.

[0043] In some embodiments, the In element distribution of the lower waveguide layer 102 has a curve distribution of a sixth target function. In some embodiments, the In element distribution of the lower waveguide layer 102 has a curve distribution of the third quadrant of a function y = J1 + K1 * x -g1 , where g1 is an odd number and g1 > 1; J1 and K1 are constants.

[0044] In some embodiments, the In / H element ratio distribution of the lower waveguide layer 102 has a curve distribution of a seventh target function. In some embodiments, the In / H element ratio distribution of the lower waveguide layer 102 has a curve distribution of the third quadrant of a function y = L1 + M1 * x -h1 , where h1 is an odd number and h1 > 1; L1 and M1 are constants.

[0045] In some embodiments, the In / C atomic ratio distribution of the lower waveguide layer 102 has a curve distribution of an eighth target function. In some embodiments, the In / C atomic ratio distribution of the lower waveguide layer 102 has a curve distribution of a third quadrant of a function y = N1 + P1 * x -j1 where j1 is an odd number and j1 > 1; N1 and P1 are constants.

[0046] In some embodiments, the In / O atomic ratio distribution of the lower waveguide layer 102 has a curve distribution of a ninth target function. In some embodiments, the In / O atomic ratio distribution of the lower waveguide layer 102 has a curve distribution of a third quadrant of a function y = Q1 + R1 * x -k1 where k1 is an odd number and k1 > 1; Q1 and R1 are constants.

[0047] In some embodiments, h1 < k1 < j1 < g1.

[0048] In some embodiments, the upper waveguide layer 104 can be the same as or different from the lower waveguide layer 102.

[0049] In some embodiments, the upper waveguide layer 104 can include any one or more of GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAsN, AlInAs, AlInP, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga2O3, BN, and diamond, etc.

[0050] In some embodiments, the upper waveguide layer 104 is a strain-modulated upper waveguide layer. In some embodiments, the strain-modulated upper waveguide layer includes any one or more of InGaN, GaN, InN, AlInGaN, etc.

[0051] In some embodiments, the Peak Drift Velocity distribution of the peak electrons of the strain-modulated upper waveguide layer has an arc-shaped distribution.

[0052] In some embodiments, the Peak Drift Velocity distribution of the peak electrons of the strain-modulated upper waveguide layer has a curve distribution of a tenth target function. In some embodiments, the Peak Drift Velocity distribution of the peak electrons of the strain-modulated upper waveguide layer has a curve distribution of a third quadrant of a function y = A4 + B4 * log a4a4 * ((m4+x) / (m4-x)), where 0 < a4 < 1, m4 > 0; A4 and B4 are constants.

[0053] By regulating the drift velocity distribution of the peak electrons of the upper waveguide layer, the electric field shielding ability induced by the peak electrons, the strain polarization field, the polarization effect, the energy band step and the hole migration barrier of the upper waveguide layer and the active layer, the electron leakage and the carrier injection non-uniformity, the process of stimulated radiation greater than loss, and the threshold current density are reduced.

[0054] In some embodiments, the strain potential distribution of the strain-modulated upper waveguide layer has an arc-shaped distribution. The strain potential distribution of the upper waveguide layer refers to the potential energy change caused by mechanical strain in the upper waveguide layer of the laser.

[0055] In some embodiments, the strain potential distribution of the strain-modulated upper waveguide layer has a curve distribution of the eleventh objective function. In some embodiments, the strain potential distribution of the strain-modulated upper waveguide layer has a curve distribution of the function y = C4 + D4 * log b4 ((n4+x)*(n4-x)), where b4 > 1, n4 > 0; C4 and D4 are constants.

[0056] In some embodiments, the bulk modulus distribution of the strain-modulated upper waveguide layer has a curve distribution of the twelfth objective function. The bulk modulus distribution of the upper waveguide layer refers to the case where the bulk modulus of the upper waveguide layer material changes with space in the laser.

[0057] In some embodiments, the bulk modulus distribution of the strain-modulated upper waveguide layer has a curve distribution of the function y = E4 + F4 * log c4 ((j4+x) / (j4-x)), where c4 > 1, j4 > 0; E4 and F4 are constants.

[0058] By regulating the strain potential distribution and the bulk modulus distribution of the strain-modulated upper waveguide layer, the spontaneous polarization and piezoelectric polarization effects between the upper waveguide layer and the active layer can be suppressed, the QCSE effect of the active layer can be suppressed, the energy band tilt can be reduced, the spatial overlap probability and uniformity of the electron-hole wave function of the active layer can be improved, and the problems of strain-induced interface crystal quality deterioration, defect density, etc. can be improved, thereby improving the radiation recombination efficiency, laser power and gain uniformity, and laser lifetime.

[0059] In some embodiments, the polar optical phonon energy distribution of the strain-modulated upper waveguide layer has a curve distribution of a thirteenth objective function. Polar optical phonons refer to a mode of lattice vibration in a crystal that is caused by a change in electric field.

[0060] In some embodiments, the polar optical phonon energy distribution of the strain-modulated upper waveguide layer has a curve distribution of a function y=G4+H4*log d4 ((k4+x) / (k4-x)) where d4>1, k4>0; G4and H4are constants.

[0061] By the polar optical phonon energy distribution of the strain-modulated upper waveguide layer, the phonon transport and distribution of the upper waveguide layer are regulated, the phonon scattering at the interface between the upper waveguide layer and the upper cladding layer and the interface between the upper waveguide layer and the active layer is reduced, and the heat generated by the Stokes shift formed by the difference in photon energy between the pump light and the oscillation light is reduced, thereby reducing the thermal stress and temperature distribution uniformity of the laser and reducing the optical catastrophe ratio of the laser.

[0062] In some embodiments, the drift velocity distribution of the peak electrons, the deformation potential distribution, the bulk modulus distribution, and the polar optical phonon energy distribution of the strain-modulated upper waveguide layer satisfy a second preset condition. In some embodiments, the drift velocity distribution of the peak electrons, the deformation potential distribution, the bulk modulus distribution, and the polar optical phonon energy distribution of the strain-modulated upper waveguide layer have the following relationship: 0

[0063] In some embodiments, the In element distribution of the strain-modulated upper waveguide layer has a curve distribution of a fourteenth objective function. In some embodiments, the In element distribution of the strain-modulated upper waveguide layer has a curve distribution of a function y=K4+J4log f4 ((l4+x) / (l4-x)) where 0

[0064] In some embodiments, the In / C element ratio distribution of the strain-modulated upper waveguide layer has a curve distribution of a fifteenth objective function. In some embodiments, the In / C element ratio distribution of the strain-modulated upper waveguide layer has a curve distribution of a function y=M4+N4*log g4 ((u4+x) / (u4-x)) where 0

[0065] In some embodiments, the In / H element ratio distribution of the strain-modulated upper waveguide layer has a curve distribution of a sixteenth objective function. In some embodiments, the In / H element ratio distribution of the strain-modulated upper waveguide layer has a curve distribution of a function y=P4+Q4*log p4a curve distribution of ((v4+x) / (v4-x)), where 0

[0066] In some embodiments, the In / O element ratio distribution of the strain-modulated upper waveguide layer has a curve distribution of a seventeenth objective function. In some embodiments, the In / O element ratio distribution of the strain-modulated upper waveguide layer has a curve distribution of a function y = R4 + S4*log q4 a curve distribution of ((w4+x) / (w4-x)), where 0

[0067] In some embodiments, 0 < p4 < g4 < q4 < f4 < 1.

[0068] The active layer 103 refers to a region in a semiconductor laser that is specifically used for generating, amplifying, or modulating optical or electrical signals. For example, the active layer 103 is a quantum well structure.

[0069] In some embodiments, the active layer 103 is a periodic structure composed of a well layer and a barrier layer. In some embodiments, the active layer 103 has a period number m, where 3 ≥ m ≥ 1.

[0070] In some embodiments, the well layer and / or the barrier layer of the active layer 103 includes any one or a combination of GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAsN, AlInAs, AlInP, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga2O3, BN, and diamond, etc.

[0071] In some embodiments, the thickness of the well layer of the active layer 103 is within a first preset range. In some embodiments, the thickness of the well layer of the active layer 103 is 5-200 angstroms. In some embodiments, the thickness of the well layer of the active layer 103 is 8-180 angstroms. In some embodiments, the thickness of the well layer of the active layer 103 is 10-150 angstroms.

[0072] In some embodiments, the thickness of the barrier layer of the active layer 103 is within a second preset range. In some embodiments, the thickness of the barrier layer of the active layer 103 is 5-250 angstroms. In some embodiments, the thickness of the barrier layer of the active layer 103 is 8-230 angstroms. In some embodiments, the thickness of the barrier layer of the active layer 103 is 10-200 angstroms.

[0073] In some embodiments, the active layer 103 is a strongly coherent quantum well. In some embodiments, the strongly coherent quantum well comprises a first strongly coherent quantum well and a second strongly coherent quantum well.

[0074] In some embodiments, the first strongly coherent quantum well and / or the second strongly coherent quantum well comprises a periodic structure of a plurality of well layers and a plurality of barrier layers. In some embodiments, the first strongly coherent quantum well has a first number of periods. In some embodiments, the first strongly coherent quantum well has one period. In some embodiments, the second strongly coherent quantum well has a second number of periods, which is the same as or different from the first number. In some embodiments, the second strongly coherent quantum well has one to three periods.

[0075] In some embodiments, the first strongly coherent quantum well and / or the second strongly coherent quantum well comprises a combination of any one or more of InGaN, GaN, InN, AlInN, AlN, AlInGaN, AlGaN, etc.

[0076] In some embodiments, the first strongly coherent quantum well has a first function of the polar optical phonon energy distribution, and the second strongly coherent quantum well has a second function of the polar optical phonon energy distribution.

[0077] In some embodiments, the first strongly coherent quantum well has a function y=A3+sin(B3x+C3) of the polar optical phonon energy distribution, and the second strongly coherent quantum well has a function y=D3+cos(E3x+F3) of the polar optical phonon energy distribution. Wherein A3, B3, C3, D3, E3, and F3 are constants.

[0078] In some embodiments, the first strongly coherent quantum well has a third function of the peak rate field distribution, and the second strongly coherent quantum well has a fourth function of the peak rate field distribution.

[0079] In some embodiments, the first strongly coherent quantum well has a function y=G3+sin(H3x+I3) of the peak rate field distribution, and the second strongly coherent quantum well has a function y=J3+cos(K3x+L3) of the peak rate field distribution. Wherein G3, H3, I3, J3, K3, and L3 are constants.

[0080] In some embodiments, the first strongly coherent quantum well has a fifth function of the valence band effective state density distribution, and the second strongly coherent quantum well has a sixth function of the valence band effective state density distribution.

[0081] In some embodiments, the density distribution of the valence band effective state of the first strongly coherent quantum well has a curve distribution of a function y = M3 + cos(N3x + O3), and the density distribution of the valence band effective state of the second strongly coherent quantum well has a curve distribution of a function y = P3 + sin(Q3x + R3). Wherein, M3, N3, O3, P3, Q3, and R3 are constants.

[0082] In some embodiments, the absorption coefficient distribution of the photon energy of the first strongly coherent quantum well has a curve distribution of a seventh function, and the absorption coefficient distribution of the photon energy of the second strongly coherent quantum well has a curve distribution of an eighth function.

[0083] In some embodiments, the absorption coefficient distribution of the photon energy of the first strongly coherent quantum well has a curve distribution of a function y = T3 + sin(S3x + U3), and the absorption coefficient distribution of the photon energy of the second strongly coherent quantum well has a curve distribution of a function y = V3 + cos(W3x + Z3). Wherein, T3, S3, U3, V3, W3, and Z3 are constants.

[0084] In some embodiments, the polarized optical phonon energy distribution, the peak rate electric field distribution, the density distribution of the valence band effective state, and the absorption coefficient distribution of the photon energy of the first strongly coherent quantum well and the second strongly coherent quantum well have the following relationship: D3≤P3≤J3≤V3≤A3≤M3≤G3≤T3.

[0085] Through the above-mentioned first strongly coherent quantum well and the second strongly coherent quantum well, the electron-hole quantization of the active layer can be improved, the heavy hole band and the light hole band can be split or degenerate, the coupling time constant of the electron and the photon in the active layer can be reduced, the complexity of the laser transverse mode and the light field dissipation can be reduced, the far field image can form a Gaussian pattern in the c-axis direction, the low aspect ratio far field fast Fourier transform (FFP) image can be realized, the light field leakage to the substrate can be reduced, and the coherence of the output laser can be improved. At the same time, the inter-mode variation of the longitudinal mode and the number of longitudinal modes can be reduced, the longitudinal divergence angle of the main spot light field can be increased, the far field spot can be an elliptical ripple field image, and the laser spot quality can be improved.

[0086] The electron blocking layer (EBL) 105 can be used to maintain the recombination of a large number of carriers (electrons and holes), thereby enhancing the efficiency of light emission.

[0087] In some embodiments, the electron blocking layer 105 comprises any one or more of a combination of GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAsN, AlInAs, AlInP, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga2O3, BN, and diamond, etc.

[0088] In some embodiments, as shown in FIG. 1A, the substrate 100 has a graded polarization layer 107 between the substrate 100 and the lower cladding layer 101. Figure 1

[0089] The graded polarization layer can adjust the polarization properties of the material by the gradual change of the composition or the crystal structure of the material, to achieve better electro-optical performance.

[0090] In some embodiments, the graded polarization layer 107 comprises any one or more of a combination of AlGaN, GaN, AlInN, AlInGaN, InGaN, InGaN / GaN superlattice, InGaN / AlInGaN superlattice, InGaN / AlInN superlattice, AlGaN / AlGaN superlattice, AlGaN / GaN superlattice, AlGaN / AlInGaN superlattice, and AlGaN / AlInN superlattice, etc.

[0091] In some embodiments, the piezoelectric polarization coefficient distribution of the graded polarization layer 107 has any one of an arc-shaped distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution, etc.

[0092] In some embodiments, the piezoelectric polarization coefficient distribution of the graded polarization layer 107 has a curve distribution of the eighteenth objective function. In some embodiments, the piezoelectric polarization coefficient distribution of the graded polarization layer 107 has a curve distribution of the third quadrant of the function y = P2+ Q2*x -A2 , where A2 is an odd number, and A2 > 1; P2 and Q2 are constants.

[0093] In some embodiments, the spontaneous polarization coefficient distribution of the graded polarization layer 107 has any one of an arc-shaped distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution, etc.

[0094] ​In some embodiments, the spontaneous polarization coefficient distribution of the graded polarization layer 107 has a curve distribution of the nineteenth objective function. In some embodiments, the spontaneous polarization coefficient distribution of the graded polarization layer 107 has a function y=R2*S2*x -B2 The curve distribution of the second quadrant, where B2 is an even number and B2>1; R2 and S2 are constants.

[0095] In some embodiments, the Philips ionization degree distribution of the graded polarization layer 107 has any one of an arc distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution.

[0096] In some embodiments, the Phillips ionization degree distribution of the graded polarization layer 107 has a curve distribution of the twentieth objective function. In some embodiments, the Phillips ionization degree distribution of the graded polarization layer 107 has a function y=T2+U2*x -c2 The curve distribution of the second quadrant, where C2 is an even number and C2>1; T2 and U2 are constants.

[0097] In some embodiments, the elastic modulus distribution of the graded polarization layer 107 has any one of an arc distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution.

[0098] In some embodiments, the elastic coefficient distribution of the graded polarization layer 107 has a curve distribution of the twenty-first objective function. In some embodiments, the elastic coefficient distribution of the graded polarization layer 107 has a function y=V2+W2*x -D2 The curve distribution of the second quadrant, where D2 is an even number and D2>1; V2 and W2 are constants.

[0099] In some embodiments, D2≤C2≤A2≤B2.

[0100] In some embodiments, the Al element concentration distribution of the graded polarization layer 107 has a curve distribution of the twenty-second objective function. In some embodiments, the Al element concentration distribution of the graded polarization layer 107 has a function y=x -E2 The curve distribution in the third quadrant is as follows, where E2 is an odd number and E2>1.

[0101] In some embodiments, the C element concentration distribution of the graded polarization layer 107 has a curve distribution of the twenty-third objective function. In some embodiments, the C element concentration distribution of the graded polarization layer 107 has a function y=x -F2 The curve distribution in the third quadrant is as follows, where F2 is an odd number and F2>1.

[0102] In some embodiments, the H element concentration distribution of the graded polarization layer 107 has a curve distribution of a twenty-fourth target function. In some embodiments, the H element concentration distribution of the graded polarization layer 107 has a curve distribution of a third quadrant of a function y = x -G2 where G2 is an odd number and G2 > 1.

[0103] In some embodiments, the O element concentration distribution of the graded polarization layer 107 has a curve distribution of a twenty-fifth target function. In some embodiments, the O element concentration distribution of the graded polarization layer 107 has a curve distribution of a third quadrant of a function y = x -G2 where G2 is an odd number and G2 > 1.

[0104] In some embodiments, H2≤ F2≤ G2≤ E2.

[0105] In some embodiments, the thickness of the graded polarization layer 107 is within a third preset range. In some embodiments, the thickness of the graded polarization layer 107 is 10-40000 angstroms. In some embodiments, the thickness of the graded polarization layer 107 is 20-35000 angstroms. In some embodiments, the thickness of the graded polarization layer 107 is 30-30000 angstroms.

[0106] By setting the graded polarization layer 107 to the above structure, the polarization effect of the laser can be reduced, the hole migration potential barrier can be reduced, the electron leakage can be reduced, the carrier concentration required for the laser to reach the threshold can be reduced, and the internal loss and free carrier absorption loss of the laser can be reduced, thereby improving the temperature stability and device aging life of the laser.

[0107] In some embodiments, the covalent bond energy distribution of the graded polarization layer 107 has any one of an arc-shaped distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution.

[0108] In some embodiments, the covalent bond energy distribution of the graded polarization layer 107 has a curve distribution of a twenty-sixth target function. In some embodiments, the covalent bond energy distribution of the graded polarization layer 107 has a curve distribution of a third quadrant of a function y = x -J2 where J2 is an odd number and J2 > 1.

[0109] In some embodiments, the polarized optical phonon energy distribution of the graded polarization layer 107 has any one of an arc-shaped distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution.

[0110] In some embodiments, the polarized optical phonon energy distribution of the graded polarization layer 107 has a curve distribution of a twenty-seventh target function. In some embodiments, the polarized optical phonon energy distribution of the graded polarization layer 107 has a curve distribution of a third quadrant of a function y = x -K2a third quadrant curve distribution of the function y = x

[0111] In some embodiments, the transverse sound velocity distribution of the graded polarization layer 107 has any one of an arc-shaped distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution, etc.

[0112] In some embodiments, the transverse sound velocity distribution of the graded polarization layer 107 has a curve distribution of the twenty-eighth objective function. In some embodiments, the transverse sound velocity distribution of the graded polarization layer 107 has a curve distribution of the second quadrant of the function y = x -M2 a third quadrant curve distribution of the function y = x

[0113] In some embodiments, the drift velocity distribution of the saturated electrons of the graded polarization layer 107 has any one of an arc-shaped distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution, etc.

[0114] In some embodiments, the drift velocity distribution of the saturated electrons of the graded polarization layer 107 has a curve distribution of the twenty-ninth objective function. In some embodiments, the drift velocity distribution of the saturated electrons of the graded polarization layer 107 has a curve distribution of the second quadrant of the function y = x -N2 a third quadrant curve distribution of the function y = x

[0115] In some embodiments, K2≤J2≤M2≤N2.

[0116] In some embodiments, the piezoelectric polarization coefficient distribution, the spontaneous polarization coefficient distribution, the Philips ionization degree distribution, the elastic coefficient distribution, the covalent bond energy distribution, the polar optical phonon energy distribution, the transverse sound velocity distribution, and the drift velocity distribution of the saturated electrons of the graded polarization layer 107 satisfy a third preset condition. In some embodiments, the piezoelectric polarization coefficient distribution, the spontaneous polarization coefficient distribution, the Philips ionization degree distribution, the elastic coefficient distribution, the covalent bond energy distribution, the polar optical phonon energy distribution, the transverse sound velocity distribution, and the drift velocity distribution of the saturated electrons of the graded polarization layer 107 have the following relationship: D2≤C2≤K2≤J2≤M2≤N2≤A2≤B2.

[0117] To achieve the above distribution, the following parameters can be used: Green laser - project Conventional laser Invention laser Variation amplitude threshold current density (kA / cm 2 ) 4.2 1.39 -67％ 1000H burnout lamp ratio 2％ 0.21％ -90％ Internal optical loss (cm -1 )]]> 44.2 10.3 -77％

[0118] The graded polarization layer 107 weakens the restriction of the abnormal potential barrier on the carriers by carrier diffusion, improves the symmetry of the conduction band and the heavy hole band, so that the respective quasi-Fermi levels enter the respective energy bands with equal probability under the same injection current, reduces the state density in the valence band and increases the transition probability to reduce the threshold carrier density, so as to easily meet the particle number inversion condition and reduce the threshold of the laser.

[0119] The conventional laser and the semiconductor laser provided by the embodiments of the present application are tested by a laser chip testing device, wherein the ridge width of the laser is designed as 45 um, the cavity length is 1200 um, the testing current is 0-4 A, the pulse or continuous mode is used for testing, and the testing environment temperature is 25℃. The light power signal of the laser is collected by an integrating sphere, so as to test the light power and the threshold current density (the threshold current density is the initial current density of the laser). The sample is placed into an oven for aging test, wherein the aging temperature is 65℃, the aging current is 3 A, and the light power attenuation of different aging time is tested. The laser in the embodiments of the present application can significantly improve the mode gain and the light emitting power of the semiconductor laser, and reduce the threshold current. The test results are as follows: Project Conventional laser Invention laser Variation amplitude Optical catastrophe ratio (PPM) 21 6 -71％ threshold current density (kA / cm 2 ) 2.14 0.87 -59％ Optical power (W) @ 3A 4.7 5.9 26％ Aging life (65°C @ 3A) 16000 23000 44％

[0120] In addition, Figure 2 and Figure 3 are structure secondary ion mass spectrometry (SIMS) diagrams of the nitride semiconductor laser according to the embodiments of the present application. Figure 4 and Figure 5 are transmission electron microscope (TEM) diagrams of the upper cladding layer 106 and the upper waveguide layer 104 of the nitride semiconductor laser according to the embodiments of the present application, respectively, under the scale of 100 nm. Figure 6 is a TEM diagram of the active layer 103 of the nitride semiconductor laser according to the embodiments of the present application, under the scale of 10 nm. Figure 7 is a TEM diagram of the lower waveguide layer 102 of the nitride semiconductor laser according to the embodiments of the present application, under the scale of 200 nm. Figure 8 is a TEM diagram of the electron blocking layer 105 of the nitride semiconductor laser according to the embodiments of the present application, under the scale of 20 nm.

[0121] Figure 9 is a structure SIMS diagram of the nitride semiconductor laser according to another embodiment of the present application.

[0122] Figure 10 is a SIMS diagram of the graded polarization layer 107 of the nitride semiconductor laser according to the embodiments of the present application; Figure 11 is a partial enlarged view of the SIMS diagram of the graded polarization layer 107 of the nitride semiconductor laser according to the embodiments of the present application.

[0123] Figure 12 and Figure 13 are SIMS diagrams of the strong coherent quantum well of the nitride semiconductor laser according to the embodiments of the present application.

Claims

1. A nitride semiconductor laser, characterized in that: include: A substrate, a lower cladding layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer, and an upper cladding layer are sequentially arranged from bottom to top; The lower waveguide layer is a lower waveguide layer with a gradient refractive index, wherein the refractive index decreases, and the decreasing trend curve has a function y=C1+D1*x -d1 The curve distribution in the third quadrant of , where d1 is an odd number and d1>1.

2. The laser according to claim 1, characterized in that The lower waveguide layer comprises any one or more combinations of InGaN, GaN, InN, AlInGaN, InGaN / GaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInN superlattice, and InGaN / AlInGaN superlattice; The peak velocity electric field distribution of the lower waveguide layer has an arc-shaped distribution.

3. The laser according to claim 2, characterized in that The peak velocity electric field distribution of the lower waveguide layer has a function y=log a1 Curve distribution of x, where a1>1; The drift velocity distribution of the saturated electrons in the lower waveguide layer has an arc-shaped distribution; the drift velocity distribution of the saturated electrons in the lower waveguide layer has a function y=E1+F1*x -b1 The curve distribution of the third quadrant, where b1 is an odd number and b1>1; The density distribution of the valence band effective state of the lower waveguide layer has the function y=G1+H1*(c1 x +1) / (c1 x -1) curve distribution in the third quadrant, where c1>1; The longitudinal sound velocity distribution of the lower waveguide layer has the function y=A1+B1*e x / x 2 The curve distribution of the second quadrant; The peak velocity electric field distribution of the lower waveguide layer, the drift velocity distribution of the saturated electrons, and the density distribution of the valence band effective state have the following relationship: 1<c1≤b1≤a1; The In element distribution of the lower waveguide layer has the function y=J1+K1*x -g1 The curve distribution of the third quadrant, where g1 is an odd number and g1>1; The In / H element ratio distribution of the lower waveguide layer has the function y=L1+M1*x -h1 The curve distribution of the third quadrant, where h1 is an odd number and h1>1; The In / C element ratio distribution of the lower waveguide layer has a function y=N1+P1*x -j1 The curve distribution of the third quadrant, where j1 is an odd number and j1>1; The In / O element ratio distribution of the lower waveguide layer has a function y=Q1+R1*x -k1 The curve distribution of the third quadrant, where k1 is an odd number and k1>1; Among them: h1≤k1≤j1≤g1.

4. The laser according to claim 1, characterized in that A graded polarization layer is provided between the substrate and the lower cladding layer; The graded polarization layer includes any one or more combinations of AlGaN, GaN, AlInN, AlInGaN, InGaN, InGaN / GaN superlattice, InGaN / AlInGaN superlattice, InGaN / AlInN superlattice, AlGaN / AlGaN superlattice, AlGaN / GaN superlattice, AlGaN / AlInGaN superlattice, and AlGaN / AlInN superlattice.

5. The laser according to claim 4, wherein The piezoelectric polarization coefficient distribution of the graded polarization layer has any one of an arc distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution; the piezoelectric polarization coefficient distribution of the graded polarization layer has a function y=P2+Q2*x -A2 The curve distribution of the third quadrant, where A2 is an odd number and A2>1; The spontaneous polarization coefficient distribution of the graded polarization layer has any one of an arc distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution; the spontaneous polarization coefficient distribution of the graded polarization layer has a function y=R2*S2*x -B2 The curve distribution of the second quadrant, where B2 is an even number and B2>1; The Philips ionization degree distribution of the graded polarization layer has any one of an arc distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution; the Philips ionization degree distribution of the graded polarization layer has a function y=T2+U2*x -C2 The curve distribution of the second quadrant, where C2 is an even number and C2>1; The elastic coefficient distribution of the graded polarization layer has any one of an arc distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution; the elastic coefficient distribution of the graded polarization layer has a function y=V2+W2*x -D2 The curve distribution of the second quadrant, where D2 is an even number and D2>1; Among them: D2≤C2≤A2≤B2; The Al element concentration distribution of the graded polarization layer has a function y=x -E2 The curve distribution of the third quadrant, where E2 is an odd number and E2>1; The C element concentration distribution of the graded polarization layer has a function y=x -F2 The curve distribution of the third quadrant, where F2 is an odd number and F2>1; The H element concentration distribution of the graded polarization layer has a function y=x -G2 The curve distribution of the third quadrant, where G2 is an odd number and G2>1; The O element concentration distribution of the graded polarization layer has a function y=x -H2 The curve distribution of the third quadrant, where H2 is an odd number and H2>1; Among them: H2≤F2≤G2≤E2; The thickness of the graded polarization layer is 30 to 30,000 angstroms.

6. The laser according to claim 4, wherein The covalent bond energy distribution of the graded polarization layer has any one of an arc distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution; the covalent bond energy distribution of the graded polarization layer has a function y=x -J2 The curve distribution of the third quadrant, where J2 is an odd number and J2>1; The polarimetric phonon energy distribution of the graded polarimetric layer has any one of an arc distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution; the polarimetric phonon energy distribution of the graded polarimetric layer has a function y=x -K2 The curve distribution of the third quadrant, where K2 is an odd number and K2>1; The transverse sound velocity distribution of the graded polarization layer has any one of an arc distribution, a circular arc distribution, a curved distribution, or an irregular curve distribution; the transverse sound velocity distribution of the graded polarization layer has a function y=x -M2 The curve distribution of the third quadrant, where M2 is an odd number and M2>1; The drift velocity distribution of the saturated electrons in the graded polarization layer has any one of an arc distribution, a circular arc distribution, a curved distribution, and an irregular curve distribution; the drift velocity distribution of the saturated electrons in the graded polarization layer has a function y=x -N2 The curve distribution of the second quadrant, where N2 is an even number and N2>1; Among them: K2≤J2≤M2≤N2; The piezoelectric polarization coefficient distribution, the spontaneous polarization coefficient distribution, the Philips ionization degree distribution, the elastic coefficient distribution, the covalent bond energy distribution, the polarimetric phonon energy distribution, the transverse sound velocity distribution, and the drift velocity distribution of the saturated electrons of the graded polarization layer have the following relationship: D2≤C2≤K2≤J2≤M2≤N2≤A2≤B2.

7. The laser according to claim 4, wherein The active layer is a strongly coherent quantum well; the strongly coherent quantum well includes a first strongly coherent quantum well and a second strongly coherent quantum well; The first strongly coherent quantum well and the second strongly coherent quantum well are periodically structured by a plurality of well layers and a plurality of barrier layers, the period number of the first strongly coherent quantum well is one pair, and the period number of the second strongly coherent quantum well is 1 to 3; The first strongly coherent quantum well and the second strongly coherent quantum well include any one or more combinations of InGaN, GaN, InN, AlInN, AlN, AlInGaN, and AlGaN; The polarization optical phonon energy distribution of the first strongly coherent quantum well has a curve distribution of function y=A3+sin(B3x+C3), and the polarization optical phonon energy distribution of the second strongly coherent quantum well has a curve distribution of function y=D3+cos(E3x+F3).

8. The laser according to claim 7, wherein The peak rate electric field distribution of the first strongly coherent quantum well has a curve distribution of function y=G3+sin(H3x+I3), and the peak rate electric field distribution of the second strongly coherent quantum well has a curve distribution of function y=J3+cos(K3x+L3); The density distribution of the valence band effective state of the first strongly coherent quantum well has a curve distribution of function y=M3+cos(N3x+O3), and the density distribution of the valence band effective state of the second strongly coherent quantum well has a curve distribution of function y=P3+sin(Q3x+R3); The absorption coefficient distribution of the photon energy of the first strongly coherent quantum well has a curve distribution of the function y=T3+sin(S3x+U3), and the absorption coefficient distribution of the photon energy of the second strongly coherent quantum well has a curve distribution of the function y=V3+cos(W3x+Z3); The polariton phonon energy distribution, the peak rate electric field distribution, the density distribution of the valence band effective state, and the absorption coefficient distribution of the photon energy of the first strongly coherent quantum well and the second strongly coherent quantum well have the following relationship: D3≤P3≤J3≤V3≤A3≤M3≤G3≤T3.

9. The laser according to claim 1, characterized in that The upper waveguide layer is a strain-modulated upper waveguide layer; the strain-modulated upper waveguide layer includes any one or more combinations of InGaN, GaN, InN, and AlInGaN; The peak electron drift velocity distribution of the strain-modulated upper waveguide layer has an arc-shaped distribution; the peak electron drift velocity distribution of the strain-modulated upper waveguide layer has a function y=a4+B4*log a4 The curve distribution of ((m4+x) / (m4-x)), where 0<a4<1, m4>0; The deformation potential distribution of the strain-modulated upper waveguide layer has an arc-shaped distribution; the deformation potential distribution of the strain-modulated upper waveguide layer has a function y=C4+D4*log b4 The curve distribution of ((n4+x) / (n4-x)), where b4>1, n4>0; The bulk elastic modulus distribution of the strain-modulated upper waveguide layer has the function y=E4+F4*log c4 The curve distribution of ((j4+x) / (j4-x)), where c4>1, j4>0; The polari-optical phonon energy distribution of the strain-modulated upper waveguide layer has the function y=G4+H4*log d4 The curve distribution of ((k4+x) / (k4-x)), where d4>1, k4>0; The peak electron drift velocity distribution, the deformation potential distribution, the bulk elastic modulus distribution, and the polari-optical phonon energy distribution of the strain-modulated upper waveguide layer have the following relationship: 0<a4<c4≤b4≤d4; The In element distribution of the strain-modulated upper waveguide layer has a function y=K4+J4*log f4 The curve distribution of ((l4+x) / (l4-x)), where 0<f4<1, l4>0; The In / C element ratio distribution of the strain-modulated upper waveguide layer has a function y=M4+N4*log g4 The curve distribution of ((u4+x) / (u4-x)), where 0<g4<1, u4>0; The In / H element ratio distribution of the strain-modulated upper waveguide layer has a function y=P4+Q4*log p4 The curve distribution of ((v4+x) / (v4-x)), where 0<p4<1, v4>0; The In / O element ratio distribution of the strain-modulated upper waveguide layer has a function y=R4+S4*log q4 The curve distribution of ((w4+x) / (w4-x)), where 0<q4<1, w4>0; Among them: 0<p4<g4<q4<f4<1.

10. The laser according to claim 1, characterized in that The active layer is a periodic structure composed of a well layer and a barrier layer, and the number of periods of the active layer is m, where 3≥m≥1; The well layer includes any one or more of GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAsN, AlInAs, AlInP, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga2O3, BN, and diamond, and the thickness of the well layer is 10 to 150 angstroms; The barrier layer comprises any one or more of GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAsN, AlInAs, AlInP, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga2O3, BN, and diamond, and the thickness of the barrier layer is 10 to 200 angstroms; The lower cladding layer, the upper waveguide layer, the electron blocking layer, and the upper cladding layer include any one or more combinations of GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAsN, AlInAs, AlInP, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga2O3, BN, and diamond; The substrate includes sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, Mo, TiW, CuW, Cu, sapphire / AlN composite substrate, diamond, sapphire / SiNx, sapphire / SiO2 / SiN x Composite substrate, sapphire / SiN x Any one of a / SiO2 composite substrate, a magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2, and a LiGaO2 composite substrate.

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