A gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer

Abstract

This invention proposes a gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer. The fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the effective mass distribution of light holes, and the fitting function of the electron affinity distribution obtained from SIMS testing of the graded electron affinity upper and lower waveguide layers satisfy any one of the following function distributions: Cubic function, Rational0 function, Rational1 function, Rational2 function, and Rational3 function. This invention can effectively improve laser performance.

Description

Technical Field

[0001] This application relates to the field of semiconductor optoelectronic devices, and more particularly to a gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer. Background Technology

[0002] Lasers are widely used in laser displays, laser TVs, laser projectors, communications, medical applications, weaponry, guidance, ranging, spectral analysis, cutting, precision welding, and high-density optical storage. There are many types of lasers, and they can be classified in various ways, mainly including solid-state, gas, liquid, semiconductor, and dye lasers. Compared with other types of lasers, all-solid-state semiconductor lasers have advantages such as small size, high efficiency, light weight, good stability, long lifespan, simple and compact structure, and miniaturization.

[0003] Lasers and nitride semiconductor light-emitting diodes (LEDs) differ significantly:

[0004] 1) Lasers are generated by stimulated emission of charge carriers. They have a small half-width at half-maximum and very high brightness. The output power of a single laser can be in the W range. In contrast, nitride semiconductor light-emitting diodes are generated by spontaneous emission. The output power of a single light-emitting diode is in the mW range.

[0005] 2) The operating current density of lasers reaches KA / cm2, which is more than two orders of magnitude higher than that of nitride light-emitting diodes. This results in stronger electron leakage, more severe Auger recombination, stronger polarization effect, and more severe electron-hole mismatch, leading to more severe efficiency degradation and the Droop effect.

[0006] 3) Light-emitting diodes emit spontaneous transition radiation, which is incoherent light that transitions from a high energy level to a low energy level without external influence. In contrast, lasers emit stimulated transition radiation, where the energy of the induced photon should be equal to the energy difference of the electron transition, producing coherent light that is identical to the induced photon.

[0007] 4) Different principles: Light emission diodes emit light by electrons and holes jumping to the active layer or pn junction under the action of external voltage to generate radiative recombination, while lasers require certain lasing conditions to be met before they can emit light. This requires the carriers in the active region to be reversed, the stimulated emission light to oscillate back and forth in the resonant cavity, and the propagation in the gain medium to amplify the light. When the threshold condition is met, the gain is greater than the loss, and finally, laser light is output.

[0008] Nitride semiconductor lasers have the following problems: traditional waveguide layers have uniform electron affinity, and the conduction band and valence band are step barriers, making it easy for electrons and holes to bounce, accumulate, leak, and overflow at the interface; the biggest pain points of GaN-based devices are poor hole injection, low mobility, and low activation efficiency. Summary of the Invention

[0009] To address one of the aforementioned technical problems, this invention provides a gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer.

[0010] This invention provides a gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer, comprising, from bottom to top, a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer, an upper confinement layer, and a contact layer. The lower waveguide layer includes a first lower waveguide layer and a second lower waveguide layer, with the first lower waveguide layer located below the second lower waveguide layer. The first lower waveguide layer is a constant electron affinity lower waveguide layer, the second lower waveguide layer is a graded electron affinity lower waveguide layer, and the upper waveguide layer is a graded electron affinity upper waveguide layer.

[0011] The fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the effective mass distribution of light holes, and the fitting function of the electron affinity distribution of the SIMS test of the gradient electron affinity waveguide layer satisfy any one of the following function distributions: Cubic function, Rational0 function, Rational1 function, Rational2 function, and Rational3 function.

[0012] The fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the effective mass distribution of light holes, and the fitting function of the electron affinity distribution of the waveguide layer under the gradient electron affinity test in SIMS satisfy any one of the following function distributions: Cubic function, Rational0 function, Rational1 function, Rational2 function, and Rational3 function.

[0013] Preferably, when the fitting curve of the In ion intensity distribution or In atom concentration distribution measured by SIMS on the graded electron affinity waveguide layer satisfies the Cubic function, the Cubic function is y1=A+B*x1+C*x1^2+D*x1^3, where y1 is the In ion intensity or In atom concentration measured by SIMS on the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, A is the zero bias parameter, B is the coefficient of the first term, C is the coefficient of the second term, and D is the coefficient of the third term, wherein: -5E25≤A≤0, 3E17≤B≤3E27, -5E27≤C≤0, and 3E17≤D≤3E27.

[0014] Preferably, when the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under graded electron affinity measured by SIMS satisfies the Cubic function, the Cubic function is y2=F+G*x2+H*x2^2+J*x2^3, where y1 is the In ion intensity or In atom concentration of the waveguide layer under graded electron affinity measured by SIMS, x2 is the thickness of the waveguide layer under graded electron affinity, F is the zero bias parameter, G is the coefficient of the first term, H is the coefficient of the second term, and J is the coefficient of the third term, wherein: 1E12≤F≤1E32, -3E32≤G≤0, 8E12≤H≤8E32, -3E32≤J≤0.

[0015] Preferably, when the fitting curve of the effective mass distribution of light holes in the graded electron affinity waveguide layer satisfies the Cubic function, the Cubic function is y3=K+L*x1+M*x1^2+N*x1^3, where y3 is the effective mass of light holes in the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, K is the zero-bias parameter, L is the coefficient of the first term, M is the coefficient of the second term, and N is the coefficient of the third term, wherein: 0.002≤K≤2000, -3000≤L≤0, 0.006≤M≤6000, -3000≤N≤0.

[0016] Preferably, when the fitting curve of the effective mass distribution of light holes in the waveguide layer under graded electron affinity satisfies the Cubic function, the Cubic function is y4=P+Q*x2+R*x2^2+S*x2^3, where y4 is the effective mass of light holes in the waveguide layer under graded electron affinity, x2 is the thickness of the waveguide layer under graded electron affinity, P is the zero-bias parameter, Q is the coefficient of the first term, R is the coefficient of the second term, and S is the coefficient of the third term, wherein: -1000≤P≤0, 0.007≤Q≤7000, -10000≤R≤0, and 0.004≤S≤4000.

[0017] Preferably, when the fitting curve of the electron affinity distribution of the graded electron affinity waveguide layer satisfies the Cubic function, the Cubic function is y5=T+U*x1+V*x1^2+W*x1^3, where y5 is the electron affinity of the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, T is the zero bias parameter, U is the coefficient of the first term, V is the coefficient of the second term, and W is the coefficient of the third term, wherein: -8000≤T≤0, 0.0003≤U≤30000, -50000≤V≤0, and 0.003≤W≤30000.

[0018] Preferably, when the fitting curve of the electron affinity distribution of the waveguide layer under the graded electron affinity satisfies the Cubic function, the Cubic function is y6=a+b*x2+c*x2^2+d*x2^3, where y6 is the electron affinity of the waveguide layer under the graded electron affinity, x2 is the thickness of the waveguide layer under the graded electron affinity, a is the zero-bias parameter, b is the coefficient of the first term, c is the coefficient of the second term, and d is the coefficient of the third term, wherein: 0.0002≤a≤20000, -60000≤b≤0, 0.0009≤c≤90000, -400000≤d≤0.

[0019] Preferably, when the fitting curve of the In ion intensity distribution or In atom concentration distribution measured by SIMS on the graded electron affinity waveguide layer satisfies the Rational0 function, the Rational0 function is y7 = (g + h * x1) / (1 + f * x1), where y7 is the In ion intensity or In atom concentration measured by SIMS on the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, f is the coefficient of the first-order term in the denominator, g is the constant term in the numerator, and h is the coefficient of the first-order term in the numerator, wherein: -40000 ≤ f ≤ 4000, 7E10 ≤ g ≤ 7E30, -2E31 ≤ h ≤ 2E11;

[0020] When the fitting curve of the effective mass distribution of light holes in the graded electron affinity waveguide layer satisfies the Rational0 function, the Rational0 function is y8 = (k + m * x1) / (1 + j * x1), where y8 is the effective mass of light holes in the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, j is the coefficient of the first-order term in the denominator, k is the constant term in the numerator, and m is the coefficient of the first-order term in the numerator, where: -40000 ≤ j ≤ 4000, 0.0001 ≤ k ≤ 10000, -70000 ≤ m ≤ 700;

[0021] When the fitting curve of the electron affinity distribution of the graded electron affinity waveguide layer satisfies the Rational0 function, the Rational0 function is y9=(p+q*x1) / (1+n*x1), where y9 is the electron affinity of the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, n is the coefficient of the first-order term in the denominator, p is the constant term in the numerator, and q is the coefficient of the first-order term in the numerator, where: -40000≤n≤4000, 0.0004≤p≤4000, -20000≤q≤2000.

[0022] Preferably, when the fitting curve of the In ion intensity distribution or In atom concentration distribution obtained by SIMS testing of the graded electron affinity waveguide layer satisfies the Rational1 function, the Rational1 function is y. 10=(1+r*x1) / (s+t*x1),y 10 x1 represents the In ion strength or In atom concentration measured by SIMS on the graded electron affinity waveguide layer, r represents the coefficient of the first-order term in the numerator, s represents the constant term in the denominator, and t represents the coefficient of the first-order term in the denominator, where: -20000≤r≤200, 1E-31≤s≤1E-11, -5E11≤t≤0;

[0023] When the fitted curves of the In ion intensity distribution or In atom concentration distribution obtained by SIMS testing of the graded electron affinity waveguide layer satisfy the Rational2 function, where the Rational2 function is y 11 =(u+v*x1) / (w+x1,y 11 x1 represents the In ion strength or In atom concentration measured by SIMS on the graded electron affinity waveguide layer, x1 represents the thickness of the graded electron affinity waveguide layer, u represents the numerator constant, v represents the coefficient of the first-order numerator term, and w represents the denominator constant, where: -1E30≤u≤0, 4E10≤v≤4E30, -20000≤w≤2000;

[0024] When the fitted curves of the In ion intensity distribution or In atom concentration distribution obtained by SIMS testing of the graded electron affinity waveguide layer satisfy the Rational3 function, where the Rational3 function is y 12 = (z+x1) / (i+Z*x1), y 12 x1 represents the In ion strength or In atom concentration measured by SIMS on the graded electron affinity waveguide layer, z represents the numerator constant, i represents the denominator constant, and Z represents the coefficient of the first-order term in the denominator, where: -30000≤z≤0, -5E-12≤i≤0, and 2E-31≤Z≤2E-11.

[0025] Preferably, the substrate is a GaN single crystal substrate;

[0026] The lower waveguide layer is any one or any combination of InGaN or GaN / InGaN or GaN / InGaN / GaN or InGaN / GaN or GaN or InN or AlInGaN, with a thickness of 300 angstroms to 8000 angstroms.

[0027] The active layer is an InGaN / GaN quantum well;

[0028] The upper waveguide layer is any one or any combination of InGaN or GaN / InGaN or GaN / InGaN / GaN or InGaN / GaN or GaN or InN or AlInGaN, with a thickness of 300 angstroms to 8000 angstroms.

[0029] The electron blocking layer is any one or any combination of AlGaN, GaN, InGaN, AlInGaN, and AlN, with a thickness of 5 angstroms to 800 angstroms;

[0030] The lower confinement layer is any one or any combination of AlGaN, GaN, InGaN, AlInGaN, AlN, and InN, with a thickness of 500 angstroms to 80,000 angstroms.

[0031] The upper confinement layer is any one or any combination of AlGaN, GaN, InGaN, AlInGaN, AlN, and InN, with a thickness of 500 angstroms to 9000 angstroms.

[0032] The beneficial effects of the present invention are as follows: The lower waveguide layer of the gallium nitride-based semiconductor laser in the present invention includes a first lower waveguide layer and a second lower waveguide layer, wherein the first lower waveguide layer is a constant electron affinity lower waveguide layer, the second lower waveguide layer is a graded electron affinity lower waveguide layer, and the upper waveguide layer is a graded electron affinity upper waveguide layer. The fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curves of the effective mass distribution of light holes, and the fitting functions of the electron affinity distribution of the SIMS test of the graded electron affinity upper waveguide layer satisfy any one of the following function distributions: Cubic function, Rational0 function, Rational1 function, Rational2 function, and Rational3 function. In a waveguide layer with graded electron affinity, the effective mass of light holes is small, resulting in rapid hole transport and low-impedance injection. Closer to the active region, the effective mass of light holes gradually increases, reducing hole velocity and ensuring precise confinement within the quantum well. This prevents hole carriers from overflowing, diffusing, or being lost, keeping holes in a low-effective-mass, high-mobility channel. Overall hole mobility is increased by 20%–60%, reducing valence band edge scattering and further enhancing hole mobility. The gradual change in electron affinity smoothly decreases the valence band peak Ev, eliminating steep potential barriers during hole transitions from the P-covered region to the upper waveguide and then to the active region, significantly improving hole injection efficiency. Simultaneously, the gradual change in electron affinity provides a continuous driving potential field, precisely pushing holes into the center of the quantum well. This increases the overlap integral of the electron-hole wavefunction, |⟨ψe|ψh>|², improving laser gain and reducing the threshold current. The gradual electron affinity can partially compensate for the polarization electric field, making the energy band flatter, bringing electrons and holes closer together, and enhancing stimulated recombination. The fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the effective mass distribution of light holes, and the fitting function of the electron affinity distribution in the waveguide layer under the gradual electron affinity, as measured by SIMS, satisfy any one of the following function distributions: Cubic function, Rational0 function, Rational1 function, Rational2 function, and Rational3 function. Enhancing the LH→CB transition intensity improves the TE mode gain (the dominant mode required by the laser), improves the valence band state density, and enhances optical gain. The conduction band smoothly rises from the N layer to the active region, allowing for non-reflective electron injection and preventing electron accumulation at the interface, thus reducing Joule heating and series resistance. The gradually changing electron affinity between the electrons and the lower energy waveguide layer creates a weak well or gentle barrier in the conduction band, gradually confining and compressing electrons into the quantum well, preventing leakage through the waveguide layer into the P region, thereby enhancing electron confinement and preventing electron leakage to the P side. Attached Figure Description

[0033] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0034] Figure 1 This is a schematic diagram of the structure of a gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to an embodiment of the present invention;

[0035] Figure 2 The above are the SIMS secondary ion mass spectra and x, y coordinate diagrams of the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer as described in the embodiments of the present invention.

[0036] Figure 3 The image shows the SIMS secondary ion mass spectrum of the graded electron affinity upper waveguide layer and its Cubic function fitting curve of the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to the embodiments of the present invention.

[0037] Figure 4 The image shows the SIMS secondary ion mass spectrum of the waveguide layer with graded electron affinity and its Cubic function fitting curve for the gallium nitride-based semiconductor laser with graded electron affinity waveguide layer described in the embodiments of the present invention.

[0038] Figure 5 The diagram shows the effective mass distribution of light holes in the graded electron affinity upper waveguide layer of the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to an embodiment of the present invention, and its Cubic function fitting curve.

[0039] Figure 6 The diagram shows the electron affinity distribution of the graded electron affinity upper waveguide layer and its Cubic function fitting curve of the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to an embodiment of the present invention.

[0040] Figure 7 The diagram shows the effective mass distribution of light holes in the waveguide layer under graded electron affinity and its Cubic function fitting curve for the gallium nitride-based semiconductor laser with graded electron affinity waveguide layer described in the embodiments of the present invention.

[0041] Figure 8 The diagram shows the electron affinity distribution of the waveguide layer under graded electron affinity and its Cubic function fitting curve for the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer as described in the embodiments of the present invention.

[0042] Figure 9 The image shows the SIMS secondary ion mass spectrum of the graded electron affinity upper waveguide layer of the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to an embodiment of the present invention, and its Rational O function fitting curve.

[0043] Figure 10The image shows the SIMS secondary ion mass spectrum of the graded electron affinity upper waveguide layer of the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to an embodiment of the present invention, and its Rational1 function fitting curve.

[0044] Figure 11 The image shows the SIMS secondary ion mass spectrum of the graded electron affinity upper waveguide layer of the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to an embodiment of the present invention, and its Rational2 function fitting curve.

[0045] Figure 12 The image shows the SIMS secondary ion mass spectrum of the graded electron affinity upper waveguide layer of the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to an embodiment of the present invention, and its Rational3 function fitting curve.

[0046] Figure 13 The effective mass distribution of light holes in the graded electron affinity upper waveguide layer of the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to an embodiment of the present invention is shown in the figure, along with its Rational0 function fitting curve.

[0047] Figure 14 The diagram shows the electron affinity distribution of the graded electron affinity upper waveguide layer and its Rational0 function fitting curve of the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to an embodiment of the present invention.

[0048] Figure 15 The image shows the In ion intensity distribution and Cubic function fitting curve of the waveguide layer composed of the graded electron affinity upper waveguide layer and the graded electron affinity lower waveguide layer of the gallium nitride-based semiconductor laser with graded electron affinity waveguide layer described in the embodiment of the present invention, as determined by SIMS testing.

[0049] Figure 16 The diagram shows the effective mass distribution of light holes in the waveguide layer composed of the graded electron affinity upper waveguide layer and the graded electron affinity lower waveguide layer of the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to an embodiment of the present invention, and its Cubic function fitting curve.

[0050] Figure 17 The diagram shows the electron affinity distribution of the waveguide layer, composed of the upper and lower graded electron affinity waveguide layers, and its Cubic function fitting curve for the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer as described in the embodiments of the present invention.

[0051] Figure label:

[0052] 100. Substrate; 101. Lower confinement layer; 102. Lower waveguide layer; 103. Active layer; 104. Upper waveguide layer; 105. Electron blocking layer; 106. Upper confinement layer; 107. Contact layer.

[0053] 102a, First lower waveguide layer; 102b, Second lower waveguide layer. Detailed Implementation

[0054] To make the technical solutions and advantages of the embodiments of this application clearer, the exemplary embodiments of this application will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0055] like Figure 1 and Figure 2 As shown, this embodiment proposes a gallium nitride-based semiconductor laser with a gradient electron affinity waveguide layer, comprising a substrate 100, a lower confinement layer 101, a lower waveguide layer 102, an active layer 103, an upper waveguide layer 104, a first upper confinement layer 106, an electron blocking layer 105, a second upper confinement layer 106, and a contact layer 107 arranged sequentially from bottom to top.

[0056] Specifically, in this embodiment, the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer is provided from bottom to top as follows: a substrate 100, a lower confinement layer 101, a lower waveguide layer 102, an active layer 103, an upper waveguide layer 104, a first upper confinement layer 106, an electron blocking layer 105, a second upper confinement layer 106, and a contact layer 107. The lower waveguide layer 102 includes a first lower waveguide layer 102a and a second lower waveguide layer 102b, with the first lower waveguide layer 102a located below the second lower waveguide layer 102b. The first lower waveguide layer 102a is a constant electron affinity lower waveguide layer, the second lower waveguide layer 102b is a graded electron affinity lower waveguide layer, and the upper waveguide layer 104 is a graded electron affinity upper waveguide layer.

[0057] Both the upper and lower graded electron affinity waveguide layers exhibit the In ion intensity distribution or In atom concentration distribution characteristics, light hole effective mass distribution characteristics, and electron affinity distribution characteristics as measured by SIMS, specifically as follows:

[0058] The fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the effective mass distribution of light holes, and the fitting function of the electron affinity distribution of the SIMS test of the waveguide layer with graded electron affinity satisfy any one of the following function distributions: Cubic function, Rational0 function, Rational1 function, Rational2 function, and Rational3 function.

[0059] The fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the effective mass distribution of light holes, and the fitting function of the electron affinity distribution of the waveguide layer under SIMS testing under graded electron affinity satisfy any one of the following function distributions: Cubic function, Rational0 function, Rational1 function, Rational2 function, and Rational3 function.

[0060] The Cubic function is a third-order polynomial (cubic function), belonging to one of the most basic nonlinear fitting models. It is used to fit the physical process in which the independent and dependent variables have a continuous and smooth cubic nonlinear relationship.

[0061] The Rational0 function is a zero-order rational fraction (often simplified to Rational0), with a numerator of a first-order polynomial and a denominator of a first-order polynomial with a constant term. It is the simplest model among rational functions that can describe the trend of change. This form is perfectly suited to the physical process of "single inflection point, linear-saturation transition" in GaN-based laser research.

[0062] The Rational1 function is a standard first-order rational fraction (Rational1), with both the numerator and denominator being first-order polynomials (the numerator contains a constant term 1, which is a simplified engineering form). Its core is adapted to the physical processes of "linear-asymptotic transition, single inflection point, and unbounded / bounded decay" in GaN-based laser research.

[0063] The Rational2 function is a second-order rational fraction (Rational2). The denominator is a first-order polynomial containing only linear and constant terms (without quadratic terms; the simplified form is commonly used in engineering), and the numerator is a first-order polynomial. Its core is adapted to the physical process of "linear-asymptotic fast convergence" in GaN-based laser research.

[0064] The Rational3 function is a simplified form of a third-order rational fraction (often simply called Rational3 in engineering). The numerator is a first-order polynomial containing a constant term and a linear term, and the denominator is a first-order polynomial containing a constant term and a linear term with coefficients. It is primarily adapted to the "linear-asymptotic saturation" physical process in GaN-based laser research.

[0065] Electron affinity is the energy difference between the vacuum level and the conduction band bottom (Ec), representing the ease with which electrons escape from the material surface and interface. A higher electron affinity results in a lower conduction band bottom, making it harder for electrons to escape and easier to confine them within the active region. Conversely, a lower electron affinity results in a higher conduction band bottom, making electrons more prone to overflow and leakage. A smaller effective mass of light holes leads to higher hole mobility, faster velocity, and stronger diffusion. Gradual electron affinity creates a smooth, continuous band slope, causing the conduction band bottom (Ec) to rise and fall smoothly with the gradual change in electron affinity. Simultaneously, the valence band top (Ev) follows, forming a smooth potential field, resulting in smoother electron injection and reduced interface reflection and accumulation. Gradual electron affinity also allows for a smooth rise in the conduction band of the laser, reducing electron leakage, reflection, and accumulation. Gradual effective mass of light holes optimizes valence band symmetry, optical field, and polarization, achieving electron confinement, smooth injection, and optical field constraint. In GaN… In a basic laser, graded electron affinity is used to continuously adjust the positions of the conduction band and valence band edges along the waveguide layer thickness, forming a smooth band slope. This enables unobstructed, low-loss, and highly confined injection of electrons and holes, while suppressing interface accumulation, leakage, and polarization field distortion. Graded light hole effective mass, on the other hand, achieves "high migration in the front end and strong confinement in the back end" for hole transport by continuously adjusting the dynamic behavior of holes in the valence band. This improves hole injection efficiency, wavefunction overlap integral, and optical gain. The synergistic effect of these two technologies can significantly reduce threshold current, improve slope efficiency, and enhance high-temperature characteristics and reliability.

[0066] Specifically, in this embodiment, the fitting curves of the In ion intensity distribution or In atom concentration distribution obtained by SIMS testing of the graded electron affinity upper waveguide layer and the graded electron affinity lower waveguide layer both satisfy the Cubic function, so that the fitting curves of the In ion intensity distribution or In atom concentration distribution obtained by SIMS testing of the waveguide layer composed of the graded electron affinity upper waveguide layer and the graded electron affinity lower waveguide layer both satisfy the Cubic function distribution. Figure 15 As shown, the specific manifestation is as follows:

[0067] When the fitting curves of the In ion intensity distribution or In atom concentration distribution measured by SIMS on a waveguide layer with graded electron affinity satisfy the Cubic function, the Cubic function is y1=A+B*x1+C*x1^2+D*x1^3, where y1 is the In ion intensity or In atom concentration measured by SIMS on a waveguide layer with graded electron affinity, x1 is the thickness of the waveguide layer with graded electron affinity, A is the zero-bias parameter, which is a constant term corresponding to the initial state of the physical process and its core function is to correct the zero-point shift of the dependent variable, B is the coefficient of the first term, which determines the linear trend of the dependent variable with respect to the independent variable, C is the coefficient of the second term, which determines the curvature and inflection point position of the dependent variable, and D is the coefficient of the third term, which determines the higher-order nonlinear trend of the dependent variable. Where: -5E25≤A≤0, 3E17≤B≤3E27, -5E27≤C≤0, 3E17≤D≤3E27. Figure 3 As shown, the fitting curves of the In ion intensity distribution or In atom concentration distribution of the waveguide layer measured by SIMS can satisfy the Cubic function as: y1=-5.05472E21+2.94341E22*x1-5.50166E22*x1^2+3.20221E22*x1^3.

[0068] When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer measured by SIMS under graded electron affinity satisfies the Cubic function, the Cubic function is y2=F+G*x2+H*x2^2+J*x2^3, where y1 is the In ion intensity or In atom concentration of the waveguide layer measured by SIMS under graded electron affinity, x2 is the thickness of the waveguide layer under graded electron affinity, F is the zero-bias parameter, G is the coefficient of the first term, H is the coefficient of the second term, and J is the coefficient of the third term, where: 1E12≤F≤1E32, -3E32≤G≤0, 8E12≤H≤8E32, -3E32≤J≤0. Figure 4 As shown, the fitting curves of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under SIMS testing at graded electron affinity can satisfy the Cubic function as: y2=1.52495E22-6.08078E22*x2+8.33598E22*x2^2-3.85865E22*x2^3.

[0069] In this embodiment, the fitting curves of the effective mass distribution of light holes in both the graded electron affinity upper waveguide layer and the graded electron affinity lower waveguide layer satisfy the Cubic function, so that the fitting curves of the effective mass distribution of light holes in the waveguide layer composed of the graded electron affinity upper waveguide layer and the graded electron affinity lower waveguide layer satisfy the Cubic function distribution as shown below. Figure 16 As shown, the specific manifestation is as follows:

[0070] When the fitted curve of the effective mass distribution of light holes in a graded electron affinity waveguide layer satisfies the Cubic function, the Cubic function is y3=K+L*x1+M*x1^2+N*x1^3, where y3 is the effective mass of light holes in the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, K is the zero-bias parameter, L is the coefficient of the first term, M is the coefficient of the second term, and N is the coefficient of the third term, where: 0.002≤K≤2000, -3000≤L≤0, 0.006≤M≤6000, -3000≤N≤0. Figure 5 As shown, the fitting curve of the effective mass distribution of light holes in the waveguide layer with graded electron affinity can satisfy the Cubic function: y3=2.33554-3.3514*x1+6.26435*x1^2-3.9877*x1^3.

[0071] The gradient electron affinity waveguide layer is close to the upper confinement layer 106, resulting in a small effective mass of light holes, rapid hole transport, and low-impedance injection. Close to the active region, the effective mass of light holes gradually increases, the hole velocity decreases, and they are precisely confined in the quantum well, preventing hole carriers from overflowing, diffusing, or being lost. Holes are always in a low effective mass, high mobility channel, resulting in an overall increase in hole mobility of 20%–60%, reducing valence band edge scattering, and improving hole mobility.

[0072] When the fitted curve of the effective mass distribution of light holes in a waveguide layer under graded electron affinity satisfies the Cubic function, the Cubic function is y4=P+Q*x2+R*x2^2+S*x2^3, where y4 is the effective mass of light holes in the waveguide layer under graded electron affinity, x2 is the thickness of the waveguide layer under graded electron affinity, P is the zero-bias parameter, Q is the coefficient of the first term, R is the coefficient of the second term, and S is the coefficient of the third term, where: -1000≤P≤0, 0.007≤Q≤7000, -10000≤R≤0, and 0.004≤S≤4000. Figure 7 As shown, the fitting curve of the effective mass distribution of light holes in the waveguide layer under the graded electron affinity can satisfy the Cubic function: y4=-0.16901+7.69201*x2-10.54477*x2^2+4.88108*x2^3.

[0073] The effective mass distribution of light holes in the waveguide layer under graded electron affinity can enhance the LH→CB transition intensity, increase the TE mode gain (the dominant mode required by the laser), improve the valence band state density, and enhance the optical gain.

[0074] In this embodiment, the fitting curves of the electron affinity distributions of both the upper and lower graded electron affinity waveguide layers satisfy the Cubic function, so that the fitting curves of the electron affinity distribution of the waveguide layer composed of the upper and lower graded electron affinity layers satisfy the Cubic function distribution as shown below. Figure 17 As shown, the specific manifestation is as follows:

[0075] When the fitted curve of the electron affinity distribution of the graded electron affinity waveguide layer satisfies the Cubic function, the Cubic function is y5=T+U*x1+V*x1^2+W*x1^3, where y5 is the electron affinity of the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, T is the zero-bias parameter, U is the coefficient of the first term, V is the coefficient of the second term, and W is the coefficient of the third term, where: -8000≤T≤0, 0.0003≤U≤30000, -50000≤V≤0, and 0.003≤W≤30000. Figure 6 As shown, the fitting curve of the electron affinity distribution of the waveguide layer with graded electron affinity can satisfy the Cubic function: y5=-0.79213+28.48732*x1-53.24696*x1^2+33.89557*x1^3.

[0076] The gradient electron affinity distribution in the waveguide layer smoothly decreases the valence band peak Ev, eliminating steep potential barriers during hole transitions from the P-covered layer to the waveguide and then to the active region, significantly improving hole injection efficiency. Simultaneously, the gradient electron affinity provides a continuous driving potential field, precisely pushing holes into the center of the quantum well. This increases the overlap integral of the electron-hole wavefunction, |⟨ψe|ψh>|², improving laser gain and reducing the threshold current. Furthermore, the gradient electron affinity can partially compensate for the polarization electric field, making the energy band flatter, bringing electrons and holes closer together, and enhancing stimulated recombination.

[0077] When the fitted curve of the electron affinity distribution of the waveguide layer under graded electron affinity satisfies the Cubic function, the Cubic function is y6=a+b*x2+c*x2^2+d*x2^3, where y6 is the electron affinity of the waveguide layer under graded electron affinity, x2 is the thickness of the waveguide layer under graded electron affinity, a is the zero-bias parameter, b is the coefficient of the first term, c is the coefficient of the second term, and d is the coefficient of the third term, where: 0.0002≤a≤20000, -60000≤b≤0, 0.0009≤c≤90000, -400000≤d≤0. Figure 8 As shown, the fitting curve of the electron affinity distribution of the waveguide layer under the graded electron affinity can satisfy the Cubic function: y6=20.4966-65.38205*x2+89.63056*x2^2-41.48916*x2^3.

[0078] The electron affinity distribution of the waveguide layer under the graded electron affinity causes the conduction band to rise smoothly from the N layer to the active region. Electrons are injected without reflection and do not accumulate at the interface, reducing Joule heating and series resistance. The electron affinity of the waveguide layer 102 under the graded electron affinity gradually changes, and the conduction band forms a weak well or a gentle barrier. Electrons are gradually confined and compressed into the quantum well and will not leak through the waveguide layer into the P region, thereby enhancing electron confinement and preventing electron leakage to the P side.

[0079] In some optional embodiments, when the fitting curves of the In ion intensity distribution or In atom concentration distribution measured by SIMS on the graded electron affinity waveguide layer satisfy the Rational0 function, the Rational0 function is y7 = (g + h * x1) / (1 + f * x1), where y7 is the In ion intensity or In atom concentration measured by SIMS on the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, f is the coefficient of the first-order term in the denominator, which determines the saturation and decay trends in the high independent variable segment, g is the constant term in the numerator, which determines the initial value when the independent variable is zero, and h is the coefficient of the first-order term in the numerator, which determines the linear change rate in the low independent variable segment, where: -40000 ≤ f ≤ 4000, 7E10 ≤ g ≤ 7E30, -2E31 ≤ h ≤ 2E11. Figure 9 As shown, the fitting curves of the In ion intensity distribution or In atom concentration distribution of the SIMS test on the graded electron affinity waveguide layer can satisfy the Rational0 function: y7 = (7.01392E20 - 2.0081E21 * x1) / (1 - 4.10256 * x1).

[0080] In some optional embodiments, when the fitting curve of the effective mass distribution of light holes in the graded electron affinity waveguide layer satisfies the Rational0 function, the Rational0 function is y8 = (k + m * x1) / (1 + j * x1), where y8 is the effective mass of light holes in the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, j is the coefficient of the first-order term in the denominator, k is the constant term in the numerator, and m is the coefficient of the first-order term in the numerator, where: -40000 ≤ j ≤ 4000, 0.0001 ≤ k ≤ 10000, -70000 ≤ m ≤ 700. Figure 13 As shown, the fitting curve of the effective mass distribution of light holes in the waveguide layer with graded electron affinity can satisfy the Rational0 function: y8 = (1.68014 - 6.99186 * x1) / (1 - 4.10256 * x1).

[0081] In some optional embodiments, when the fitted curve of the electron affinity distribution of the graded electron affinity waveguide layer satisfies the Rational0 function, the Rational0 function is y9 = (p + q * x1) / (1 + n * x1), where y9 is the electron affinity of the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, n is the coefficient of the first-order term in the denominator, p is the constant term in the numerator, and q is the coefficient of the first-order term in the numerator, where: -40000 ≤ n ≤ 4000, 0.0004 ≤ p ≤ 4000, -20000 ≤ q ≤ 2000. Figure 14 As shown, the fitting curve of the electron affinity distribution of the waveguide layer with graded electron affinity can satisfy the Rational0 function: y9 = (4.77883 - 18.76401 * x1) / (1 - 4.10256 * x1).

[0082] In some optional embodiments, when the fitting curves of the In ion intensity distribution or In atom concentration distribution measured by SIMS on the graded electron affinity waveguide layer satisfy the Rational1 function, the Rational1 function is y. 10 =(1+r*x1) / (s+t*x1),y 10 The in ion strength or in atom concentration is the SIMS measurement of the waveguide layer with graded electron affinity, x1 is the thickness of the waveguide layer with graded electron affinity, r is the coefficient of the first-order term in the numerator, which determines the linear rate of change in the low independent variable segment, s is the constant term in the denominator, which determines the initial reference value when the independent variable is zero, and t is the coefficient of the first-order term in the denominator, which determines the asymptotic trend in the high independent variable segment. Where: -20000≤r≤200, 1E⁻³¹≤s≤1E⁻¹¹, -5E¹¹≤t≤0. Figure 10 As shown, the fitting curves of the In ion intensity distribution or In atom concentration distribution obtained by SIMS testing of the graded electron affinity waveguide layer can satisfy the Rational1 function: y 10 = (1+(-2.86303)*x1) / ((1.42574E-21)+(-5.84917E-21)*x1).

[0083] In some optional embodiments, when the fitting curves of the In ion intensity distribution or In atom concentration distribution obtained by SIMS testing of the graded electron affinity waveguide layer satisfy the Rational2 function, the Rational2 function is y. 11 =(u+v*x1) / (w+x1,y 11x1 represents the In ion strength or In atom concentration measured by SIMS on the graded electron affinity waveguide layer, x1 represents the thickness of the graded electron affinity waveguide layer, u represents the molecule constant term, which determines the initial value when the independent variable is zero, v represents the coefficient of the first-order molecule term, which determines the asymptotic value in the high independent variable segment, and w represents the denominator constant term, which determines the transition rate between the linear segment and the saturation segment, where: -1E30≤u≤0, 4E10≤v≤4E30, -20000≤w≤2000. Figure 11 As shown, the fitting curves of the In ion intensity distribution or In atom concentration distribution obtained by SIMS testing of the graded electron affinity waveguide layer can satisfy the Rational2 function: y 11 =((-1.70965E20)+(4.89476E20)*x1) / (-0.54375+x1).

[0084] In some optional embodiments, when the fitting curves of the In ion intensity distribution or In atom concentration distribution measured by SIMS on the graded electron affinity waveguide layer satisfy the Rational3 function, the Rational3 function is y. 12 = (z+x1) / (i+Z*x1), y 12 The values ​​represent the In ion strength or In atom concentration in the SIMS-measured waveguide layer with graded electron affinity, x1 represents the thickness of the waveguide layer with graded electron affinity, z represents the numerator constant, which determines the initial reference value when the independent variable is zero, i represents the denominator constant, which determines the reference coefficient in the lower independent variable segment, and Z represents the coefficient of the first-order denominator term, which determines the asymptotic convergence rate in the higher independent variable segment. Where: -30000 ≤ z ≤ 0, -5E⁻¹² ≤ i ≤ 0, 2E⁻³¹ ≤ Z ≤ 2E⁻¹¹. Figure 12 As shown, the fitting curves of the In ion intensity distribution or In atom concentration distribution obtained by SIMS testing of the graded electron affinity waveguide layer can satisfy the Rational3 function: y 12 =(-0.34928+x1) / ((-4.97982E-22)+(2.043E-21)*x1).

[0085] In some alternative embodiments, substrate 100 is a GaN single-crystal substrate.

[0086] The lower waveguide layer 102 is any one or any combination of InGaN or GaN / InGaN or GaN / InGaN / GaN or InGaN / GaN or GaN or InN or AlInGaN, preferably a combination of GaN and InGaN, and has a thickness of 300 angstroms to 8000 angstroms.

[0087] The active layer 103 is an InGaN / GaN quantum well.

[0088] The upper waveguide layer 104 is any one or any combination of InGaN or GaN / InGaN or GaN / InGaN / GaN or InGaN / GaN or GaN or InN or AlInGaN, preferably InGaN material, and has a thickness of 300 angstroms to 8000 angstroms.

[0089] The electron blocking layer 105 is any one or any combination of AlGaN, GaN, InGaN, AlInGaN, and AlN, preferably AlGaN, and has a thickness of 5 angstroms to 800 angstroms.

[0090] The lower confinement layer 101 is any one or any combination of AlGaN, GaN, InGaN, AlInGaN, AlN, and InN, preferably AlGaN / AlGaN or AlGaN / InGaN / AlGaN combination, and has a thickness of 500 angstroms to 80,000 angstroms.

[0091] The upper confinement layer 106 is any one or any combination of AlGaN, GaN, InGaN, AlInGaN, AlN, and InN, preferably an AlGaN / AlGaN combination, and has a thickness of 500 angstroms to 9000 angstroms.

[0092] The table below compares the performance of the gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer proposed in this embodiment with that of a conventional laser. The comparison is mainly based on several aspects, including hole injection efficiency, electron injection efficiency, threshold current, slope efficiency, internal optical loss, electron leakage current ratio, hole mobility, effective mass of light holes, and electron-hole wavefunction overlap.

[0093] Traditional lasers Laser in this embodiment Performance improvement Hole injection efficiency η_inj 60%-75% 85%-95% Increase by 15%-25% Electron injection efficiency 80%-88% 92%-98% Increase by 8%-12% Threshold current I_th (typical cavity length) 40-80mA 25-50mA Decrease of 25%-45% Slope efficiency η_d 0.8-1.2W / A 1.2-1.8W / A Increase by 30%-60% Internal optical loss α_i <![CDATA[15-25cm -1 ]]> <![CDATA[8-15cm -1 ]]> Decrease of 30%-50% Electron leakage current ratio 12%-25% 4%-10% Decrease of 50%-70% Hole mobility μ_h <![CDATA[30-60cm 2 / (V·s)]]> <![CDATA[60-100cm 2 / (V·s)]]> Increase by 50%-80% Effective mass of light cavities m_lh* <![CDATA[0.25-0.30m0]]> <![CDATA[0.15-0.22m0]]> Decrease of 20%-35% Electron-hole wavefunction overlap 0.70-0.80 0.85-0.92 Increase by 10%-25%

[0094] As can be seen from the table above, the gallium nitride-based semiconductor laser with a gradient electron affinity waveguide layer proposed in this embodiment improves hole injection efficiency, electron injection efficiency, slope efficiency, hole mobility, and electron-hole wave function overlap compared to traditional lasers, while reducing threshold current, internal optical loss, electron leakage current ratio, and effective mass of light holes. Its performance is significantly better than that of traditional lasers.

[0095] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer, comprising, from bottom to top, a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer, an upper confinement layer, and a contact layer, characterized in that, The lower waveguide layer includes a first lower waveguide layer and a second lower waveguide layer. The first lower waveguide layer is located below the second lower waveguide layer. The first lower waveguide layer is a constant electron affinity lower waveguide layer, the second lower waveguide layer is a graded electron affinity lower waveguide layer, and the upper waveguide layer is a graded electron affinity upper waveguide layer. The fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the effective mass distribution of light holes, and the fitting function of the electron affinity distribution of the SIMS test of the gradient electron affinity waveguide layer satisfy any one of the following function distributions: Cubic function, Rational0 function, Rational1 function, Rational2 function, and Rational3 function. The fitting curves of the In ion intensity distribution or In atom concentration distribution, the fitting curve of the effective mass distribution of light holes, and the fitting function of the electron affinity distribution of the waveguide layer under the gradient electron affinity test in SIMS satisfy any one of the following function distributions: Cubic function, Rational0 function, Rational1 function, Rational2 function, and Rational3 function.

2. The gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to claim 1, characterized in that, When the fitting curve of the In ion intensity distribution or In atom concentration distribution measured by SIMS on the graded electron affinity waveguide layer satisfies the Cubic function, the Cubic function is y1=A+B*x1+C*x1^2+D*x1^3, where y1 is the In ion intensity or In atom concentration measured by SIMS on the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, A is the zero bias parameter, B is the coefficient of the first term, C is the coefficient of the second term, and D is the coefficient of the third term, where: -5E25≤A≤0, 3E17≤B≤3E27, -5E27≤C≤0, and 3E17≤D≤3E27.

3. The gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to claim 1, characterized in that, When the fitting curve of the In ion intensity distribution or In atom concentration distribution of the waveguide layer under the graded electron affinity test in SIMS satisfies the Cubic function, the Cubic function is y2=F+G*x2+H*x2^2+J*x2^3, where y1 is the In ion intensity or In atom concentration of the waveguide layer under the graded electron affinity test in SIMS, x2 is the thickness of the waveguide layer under the graded electron affinity, F is the zero bias parameter, G is the coefficient of the first term, H is the coefficient of the second term, and J is the coefficient of the third term, where: 1E12≤F≤1E32, -3E32≤G≤0, 8E12≤H≤8E32, -3E32≤J≤0.

4. The gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to claim 1, characterized in that, When the fitting curve of the effective mass distribution of light holes in the graded electron affinity waveguide layer satisfies the Cubic function, the Cubic function is y3=K+L*x1+M*x1^2+N*x1^3, where y3 is the effective mass of light holes in the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, K is the zero-bias parameter, L is the coefficient of the first term, M is the coefficient of the second term, and N is the coefficient of the third term, wherein: 0.002≤K≤2000, -3000≤L≤0, 0.006≤M≤6000, -3000≤N≤0.

5. The gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to claim 1, characterized in that, When the fitting curve of the effective mass distribution of light holes in the waveguide layer under graded electron affinity satisfies the Cubic function, the Cubic function is y4=P+Q*x2+R*x2^2+S*x2^3, where y4 is the effective mass of light holes in the waveguide layer under graded electron affinity, x2 is the thickness of the waveguide layer under graded electron affinity, P is the zero bias parameter, Q is the coefficient of the first term, R is the coefficient of the second term, and S is the coefficient of the third term, where: -1000≤P≤0, 0.007≤Q≤7000, -10000≤R≤0, and 0.004≤S≤4000.

6. The gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to claim 1, characterized in that, When the fitting curve of the electron affinity distribution of the graded electron affinity waveguide layer satisfies the Cubic function, the Cubic function is y5=T+U*x1+V*x1^2+W*x1^3, where y5 is the electron affinity of the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, T is the zero bias parameter, U is the coefficient of the first term, V is the coefficient of the second term, and W is the coefficient of the third term, where: -8000≤T≤0, 0.0003≤U≤30000, -50000≤V≤0, and 0.003≤W≤30000.

7. The gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to claim 1, characterized in that, When the fitting curve of the electron affinity distribution of the waveguide layer under the graded electron affinity satisfies the Cubic function, the Cubic function is y6=a+b*x2+c*x2^2+d*x2^3, where y6 is the electron affinity of the waveguide layer under the graded electron affinity, x2 is the thickness of the waveguide layer under the graded electron affinity, a is the zero bias parameter, b is the coefficient of the first term, c is the coefficient of the second term, and d is the coefficient of the third term, where: 0.0002≤a≤20000, -60000≤b≤0, 0.0009≤c≤90000, -400000≤d≤0.

8. The gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to claim 1, characterized in that, When the fitting curve of the In ion intensity distribution or In atom concentration distribution measured by SIMS on the graded electron affinity waveguide layer satisfies the Rational0 function, the Rational0 function is y7=(g+h*x1) / (1+f*x1), where y7 is the In ion intensity or In atom concentration measured by SIMS on the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, f is the coefficient of the first-order term in the denominator, g is the constant term in the numerator, and h is the coefficient of the first-order term in the numerator, where: -40000≤f≤4000, 7E10≤g≤7E30, -2E31≤h≤2E11; When the fitting curve of the effective mass distribution of light holes in the graded electron affinity waveguide layer satisfies the Rational0 function, the Rational0 function is y8 = (k + m * x1) / (1 + j * x1), where y8 is the effective mass of light holes in the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, j is the coefficient of the first-order term in the denominator, k is the constant term in the numerator, and m is the coefficient of the first-order term in the numerator, where: -40000 ≤ j ≤ 4000, 0.0001 ≤ k ≤ 10000, -70000 ≤ m ≤ 700; When the fitting curve of the electron affinity distribution of the graded electron affinity waveguide layer satisfies the Rational0 function, the Rational0 function is y9=(p+q*x1) / (1+n*x1), where y9 is the electron affinity of the graded electron affinity waveguide layer, x1 is the thickness of the graded electron affinity waveguide layer, n is the coefficient of the first-order term in the denominator, p is the constant term in the numerator, and q is the coefficient of the first-order term in the numerator, where: -40000≤n≤4000, 0.0004≤p≤4000, -20000≤q≤2000.

9. The gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to claim 1, characterized in that, When the fitted curves of the In ion intensity distribution or In atom concentration distribution obtained by SIMS testing of the graded electron affinity waveguide layer satisfy the Rational1 function, where the Rational1 function is y 10 =(1+r*x1) / (s+t*x1),y 10 x1 represents the In ion strength or In atom concentration measured by SIMS on the graded electron affinity waveguide layer, r represents the coefficient of the first-order term in the numerator, s represents the constant term in the denominator, and t represents the coefficient of the first-order term in the denominator, where: -20000≤r≤200, 1E-31≤s≤1E-11, -5E11≤t≤0; When the fitted curves of the In ion intensity distribution or In atom concentration distribution obtained by SIMS testing of the graded electron affinity waveguide layer satisfy the Rational2 function, where the Rational2 function is y 11 =(u+v*x1) / (w+x1,y 11 x1 represents the In ion strength or In atom concentration measured by SIMS on the graded electron affinity waveguide layer, x1 represents the thickness of the graded electron affinity waveguide layer, u represents the numerator constant, v represents the coefficient of the first-order numerator term, and w represents the denominator constant, where: -1E30≤u≤0, 4E10≤v≤4E30, -20000≤w≤2000; When the fitted curves of the In ion intensity distribution or In atom concentration distribution obtained by SIMS testing of the graded electron affinity waveguide layer satisfy the Rational3 function, where the Rational3 function is y 12 = (z+x1) / (i+Z*x1), y 12 x1 represents the In ion strength or In atom concentration measured by SIMS on the graded electron affinity waveguide layer, z represents the numerator constant, i represents the denominator constant, and Z represents the coefficient of the first-order term in the denominator, where: -30000≤z≤0, -5E-12≤i≤0, and 2E-31≤Z≤2E-11.

10. The gallium nitride-based semiconductor laser with a graded electron affinity waveguide layer according to claim 1, characterized in that, The substrate is a GaN single crystal substrate; The lower waveguide layer is any one or any combination of InGaN or GaN / InGaN or GaN / InGaN / GaN or InGaN / GaN or GaN or InN or AlInGaN, with a thickness of 300 angstroms to 8000 angstroms. The active layer is an InGaN / GaN quantum well; The upper waveguide layer is any one or any combination of InGaN or GaN / InGaN or GaN / InGaN / GaN or InGaN / GaN or GaN or InN or AlInGaN, with a thickness of 300 angstroms to 8000 angstroms. The electron blocking layer is any one or any combination of AlGaN, GaN, InGaN, AlInGaN, and AlN, with a thickness of 5 angstroms to 800 angstroms; The lower confinement layer is any one or any combination of AlGaN, GaN, InGaN, AlInGaN, AlN, and InN, with a thickness of 500 angstroms to 80,000 angstroms. The upper confinement layer is any one or any combination of AlGaN, GaN, InGaN, AlInGaN, AlN, and InN, with a thickness of 500 angstroms to 9000 angstroms.

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