A GaN-based compound semiconductor laser element

Abstract

This invention proposes a GaN-based compound semiconductor laser device, comprising, from bottom to top, a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper confinement layer. An electron spin state modulation layer is disposed between the lower confinement layer and the lower waveguide layer. The invention designs the piezoelectric polarization coefficient distributions of the first and second electron spin state modulation layers within the electron spin state modulation layer, as well as the relationship between the piezoelectric polarization coefficients of the lower confinement layer, the lower waveguide layer, the first electron spin state modulation layer, and the second electron spin state modulation layer. This invention can improve the performance of semiconductor laser devices.

Description

Technical Field

[0001] This application relates to the field of semiconductor optoelectronic devices, and more particularly to a GaN-based compound semiconductor laser element. 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 spontaneously emitted, and 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 quantum wells or pn junctions under the action of external voltage, generating radiative recombination. Lasers, on the other hand, 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:

[0009] 1) Large internal lattice mismatch and strain lead to strong polarization effect, and strong QCSE quantum confinement Stark effect limits the improvement of laser electro-lasing gain;

[0010] 2) The optical waveguide has high absorption loss. The inherent carbon impurities in the p-type semiconductor will compensate for the acceptor and destroy the p-type. The ionization rate of p-type doping is low. A large number of unionized Mg acceptor impurities will lead to an increase in internal optical loss. In addition, the refractive index dispersion and confinement factor of the laser decrease with increasing wavelength, resulting in a decrease in the mode gain of the laser.

[0011] 3) Increasing the thickness of the lower confinement layer can reduce the refractive index of the confinement layer, but increasing the thickness of the lower confinement layer will also limit the range of composition control, and easily cause problems such as cracking, bending and quality degradation; at the same time, the leakage of the light field mode to the substrate to form a standing wave will lead to low substrate mode suppression efficiency and poor far-field image FFP quality.

[0012] 4) The Mg acceptor activation energy of p-type semiconductors is large and the ionization efficiency is low. The hole concentration is much lower than the electron concentration and the hole mobility is much lower than the electron mobility. This leads to a severe asymmetric mismatch between electrons and holes in the quantum well, electron leakage and carrier delocalization. Hole transport in the quantum well is more difficult, carrier injection is non-uniform, gain is non-uniform, the laser gain spectrum is broadened, and the peak gain decreases.

[0013] 5) The increase in the valence band step difference of the laser makes it more difficult for holes to transport in the quantum well, resulting in non-uniform carrier injection and non-uniform gain. After laser lasing, the carrier concentration in the active region of the multi-quantum well becomes saturated, the bipolar conductivity effect weakens, the series resistance of the laser increases, and the laser voltage rises. Summary of the Invention

[0014] To address one of the aforementioned technical problems, this invention provides a GaN-based compound semiconductor laser element.

[0015] This invention provides a GaN-based compound semiconductor laser device, comprising, from bottom to top, a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper confinement layer. An electron spin state modulation layer is disposed between the lower confinement layer and the lower waveguide layer. The electron spin state modulation layer includes a first electron spin state modulation layer and a second electron spin state modulation layer, with the first electron spin state modulation layer located below the second electron spin state modulation layer. The lower confinement layer, the lower waveguide layer, the first electron spin state modulation layer, and the second electron spin state modulation layer all exhibit piezoelectric polarization coefficient distribution characteristics, and the piezoelectric polarization coefficient of the lower waveguide layer is greater than or equal to the piezoelectric polarization coefficient of the second electron spin state modulation layer, greater than or equal to the piezoelectric polarization coefficient of the first electron spin state modulation layer, and greater than or equal to the piezoelectric polarization coefficient of the lower confinement layer. The piezoelectric polarization coefficient of the first electron spin state modulation layer has a function y1 = A + Bx1. -a The curve distribution is such that a is an odd number greater than 1, x1 is the depth from the first electron spin state control layer to the second electron spin state control layer, and the piezoelectric polarization coefficient of the second electron spin state control layer has the function y2 = bx2.2 The +cx2+d curve distribution, where b < 0, and x2 is the depth of the second electron spin state control layer towards the lower waveguide layer.

[0016] Preferably, the lower confinement layer, the lower waveguide layer, the first electron spin state modulation layer, and the second electron spin state modulation layer all have spontaneous polarization coefficient distribution characteristics, and the spontaneous polarization coefficient of the lower waveguide layer ≤ the spontaneous polarization coefficient of the second electron spin state modulation layer ≤ the spontaneous polarization coefficient of the first electron spin state modulation layer ≤ the spontaneous polarization coefficient of the lower confinement layer, and the spontaneous polarization coefficient of the first electron spin state modulation layer has the function y3=C+D*k x1 The curve distribution, and k > 1, indicates that the spontaneous polarization coefficient of the second electron spin state control layer is y4 = hx2. 2 The curve distribution is +fx2+g, and h>0.

[0017] Preferably, the lower confinement layer, the lower waveguide layer, the first electron spin state modulation layer, and the second electron spin state modulation layer all have thermal expansion coefficient distribution characteristics, and the thermal expansion coefficient of the lower waveguide layer ≤ the thermal expansion coefficient of the second electron spin state modulation layer ≤ the thermal expansion coefficient of the first electron spin state modulation layer ≤ the thermal expansion coefficient of the lower confinement layer, and the thermal expansion coefficient of the first electron spin state modulation layer has a function y5=E+F*x1e x1 The curve distribution shows that the thermal expansion coefficient of the second electron spin state modulation layer has the function y6 = G + e x2 +e -x2 Curve distribution.

[0018] Preferably, the lower confinement layer, the lower waveguide layer, the first electron spin state modulation layer, and the second electron spin state modulation layer all have conduction band effective state density distribution characteristics, and the conduction band effective state density of the lower waveguide layer ≤ the conduction band effective state density of the second electron spin state modulation layer ≤ the conduction band effective state density of the first electron spin state modulation layer ≤ the conduction band effective state density of the lower confinement layer, and the conduction band effective state density distribution of the first electron spin state modulation layer has the function y7=H+J*x1 2 e x1 Curve distribution, the effective state density distribution of the conduction band of the second electron spin state control layer, y8=K+L*e x2 +M*x2 2 Curve distribution.

[0019] Preferably, in the distribution of spontaneous polarization coefficient, piezoelectric polarization coefficient, thermal expansion coefficient, and conduction band effective state density distribution function of the first electron spin state control layer, C≤A≤E≤H;

[0020] In the distribution of spontaneous polarization coefficient, piezoelectric polarization coefficient, thermal expansion coefficient, and conduction band effective density of states of the first electron spin state control layer, g≤d≤G≤K.

[0021] Preferably, the first and second electron spin state control layers are any one or any combination of GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, InGaN / GaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, InGaN / AlInGaN superlattice, InGaN / AlInGaN superlattice, GaN / AlGaN superlattice, GaN / AlInGaN superlattice, GaN / AlN superlattice, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAsN, AlInAs, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga2O3, and BN.

[0022] Preferably, the thickness of the electron spin state modulation layer is from 0.5 nm to 5000 nm.

[0023] Preferably, the active layer is a periodic structure composed of a well layer and a barrier layer, with a period number of 3 ≥ m ≥ 1. The well layer is any one or any 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, and BN. Combinations with a thickness of 10 angstroms to 100 angstroms, wherein the barrier layer is any one or any 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, and BN, with a thickness of 10 angstroms to 150 angstroms.

[0024] Preferably, the lower confinement layer, lower waveguide layer, upper waveguide layer, and upper confinement layer are any one or any 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, and BN.

[0025] Preferably, the substrate comprises sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, sapphire / AlN composite substrate, or sapphire / SiN composite substrate. x Sapphire / SiO2 / SiN x The composite substrate, or any one of the following: magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2, and LiGaO2 composite substrate.

[0026] The beneficial effects of the present invention are as follows: The present invention sets an electron spin state modulation layer between the lower confinement layer and the lower waveguide layer of a GaN-based compound semiconductor laser element, designs the piezoelectric polarization coefficient distribution of the first electron spin state modulation layer and the second electron spin state modulation layer in the electron spin state modulation layer, and the relationship between the piezoelectric polarization coefficients of the lower confinement layer, the lower waveguide layer, the first electron spin state modulation layer and the second electron spin state modulation layer. The electron spin state modulation layer enables electrons and ions to undergo spin-flip relaxation through spin conservation, generating additional electron-hole pairs from carrier kinetic energy. This relaxation leads to spin carrier multiplication, increasing the exciton generation rate of the active layer, reducing the phonon-assisted relaxation rate, enhancing the Coulomb collision rate, improving hole injection efficiency and carrier injection uniformity, accelerating the population inversion critical current of the laser, reducing the threshold current density, and suppressing electron spin polarization. This reduces the ratio of electrons and holes to opposite polarization states during spin polarization, increases the probability of electrons and holes sharing the same polarization spin direction, reduces the polarization effect and quantum confinement Stark effect of the active layer, and enhances the recombination probability of photogenerated carriers. Simultaneously, it forms tilted electron spins in interlayer electron hybridization, inducing ultralong-lifetime interlayer exciton transitions through direct momentum transitions, reducing bipolar conductivity, improving carrier saturation after lasing, improving gain uniformity, lowering the excitation threshold of the laser element, enhancing the confinement factor and peak gain, and improving the optical power and slope efficiency of the laser element. Attached Figure Description

[0027] 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:

[0028] Figure 1 This is a schematic diagram of the structure of the GaN-based compound semiconductor laser element according to an embodiment of the present invention;

[0029] Figure 2 This is a SIMS secondary ion mass spectrum of the GaN-based compound semiconductor laser device described in an embodiment of the present invention.

[0030] Figure label:

[0031] 100. Substrate; 101. Lower confinement layer; 102. Lower waveguide layer; 103. Active layer; 104. Upper waveguide layer; 105. Upper confinement layer; 106. Electron spin state modulation layer.

[0032] 106a, First electron spin state control layer; 106b, Second electron spin state control layer. Detailed Implementation

[0033] 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.

[0034] like Figure 1 and Figure 2 As shown, this embodiment proposes a GaN-based compound semiconductor laser device, which includes a substrate 100, a lower confinement layer 101, a lower waveguide layer 102, an active layer 103, an upper waveguide layer 104 and an upper confinement layer 105 arranged sequentially from bottom to top. An electron spin state modulation layer 106 is also provided in the GaN-based compound semiconductor laser device.

[0035] Specifically, in this embodiment, the GaN-based compound semiconductor laser element is provided with, from bottom to top, a substrate 100, a lower confinement layer 101, a lower waveguide layer 102, an active layer 103, an upper waveguide layer 104, and an upper confinement layer 105. An electron spin state modulation layer 106 is also provided in this semiconductor laser element. The electron spin state modulation layer 106 is disposed between the lower confinement layer 101 and the lower waveguide layer 102. The electron spin state modulation layer 106 has a two-layer structure, including a first electron spin state modulation layer 106a and a second electron spin state modulation layer 106b, wherein the first electron spin state modulation layer 106a is located below the second electron spin state modulation layer 106b.

[0036] In this embodiment, the lower confinement layer 101, the lower waveguide layer 102, the first electron spin state control layer 106a, and the second electron spin state control layer 106b all exhibit piezoelectric polarization coefficient distribution characteristics, and the piezoelectric polarization coefficients in the lower confinement layer 101, the lower waveguide layer 102, the first electron spin state control layer 106a, and the second electron spin state control layer 106b have the following relationship:

[0037] The piezoelectric polarization coefficient of the lower waveguide layer 102 is greater than or equal to the piezoelectric polarization coefficient of the second electron spin state control layer 106b, which is greater than or equal to the piezoelectric polarization coefficient of the first electron spin state control layer 106a, which is greater than or equal to the piezoelectric polarization coefficient of the lower confinement layer 101.

[0038] Furthermore, this embodiment also designs the piezoelectric polarization coefficient distribution in the first electron spin state control layer 106a and the second electron spin state control layer 106b, specifically as follows:

[0039] The piezoelectric polarization coefficient of the first electron spin state control layer 106a has the function y1=A+Bx1 -a The curve distribution is such that a is an odd number greater than 1, and x1 is the depth from the first electron spin state control layer 106a to the second electron spin state control layer 106b.

[0040] The piezoelectric polarization coefficient of the second electron spin state control layer 106b has the function y² = bx². 2 The +cx2+d curve distribution, and b<0, where x2 is the depth of the second electron spin state control layer 106b in the direction of the lower waveguide layer 102.

[0041] In this embodiment, an electron spin state modulation layer 106 is disposed between the lower confinement layer 101 and the lower waveguide layer 102 of the GaN-based compound semiconductor laser element. The piezoelectric polarization coefficient distribution of the first electron spin state modulation layer 106a and the second electron spin state modulation layer 106b in the electron spin state modulation layer 106 is designed, as well as the relationship between the piezoelectric polarization coefficients of the lower confinement layer 101, the lower waveguide layer 102, the first electron spin state modulation layer 106a and the second electron spin state modulation layer 106b. The electron spin state control layer 106 enables electrons and ions to undergo spin-flip relaxation through a spin-conservation pathway. This generates additional electron-hole pairs from carrier kinetic energy, leading to spin carrier multiplication. This increases the exciton generation rate of the active layer 103, reduces the phonon-assisted relaxation rate, enhances the Coulomb collision rate, improves hole injection efficiency and carrier injection uniformity, accelerates the population inversion critical current of the laser, reduces the threshold current density, and suppresses the degree of electron spin polarization, reducing the opposite polarization of electrons and holes during spin polarization. The ratio of states increases the probability of electrons and holes having the same polarization spin direction, reduces the polarization effect and quantum confinement Stark effect of active layer 103, enhances the recombination probability of photogenerated carriers, and simultaneously forms tilted electron spins that form interlayer electron hybridization, induces ultralong lifetime interlayer exciton transitions with direct momentum transitions, reduces bipolar conductivity, improves carrier saturation problems after lasing, improves gain uniformity, lowers the excitation threshold of laser elements, enhances confinement factor and peak gain, and improves the optical power and slope efficiency of laser elements.

[0042] In some optional embodiments, the lower confinement layer 101, the lower waveguide layer 102, the first electron spin state control layer 106a, and the second electron spin state control layer 106b also have spontaneous polarization coefficient distribution characteristics, and the spontaneous polarization coefficients in the lower confinement layer 101, the lower waveguide layer 102, the first electron spin state control layer 106a, and the second electron spin state control layer 106b have the following relationship:

[0043] The spontaneous polarization coefficient of the lower waveguide layer 102 is less than or equal to the spontaneous polarization coefficient of the second electron spin state control layer 106b, which is less than or equal to the spontaneous polarization coefficient of the first electron spin state control layer 106a, which is less than or equal to the spontaneous polarization coefficient of the lower confinement layer 101.

[0044] Furthermore, this embodiment also designs the spontaneous polarization coefficient distribution in the first electron spin state control layer 106a and the second electron spin state control layer 106b, specifically as follows:

[0045] The spontaneous polarization coefficient of the first electron spin-state modulation layer 106a has the function y3=C+D*k x1 The curve distribution is such that k > 1;

[0046] The spontaneous polarization coefficient of the second electron spin state control layer 106b is y₄ = hx₂. 2The curve distribution is +fx2+g, and h>0.

[0047] In some optional embodiments, the lower confinement layer 101, the lower waveguide layer 102, the first electron spin state control layer 106a, and the second electron spin state control layer 106b also have thermal expansion coefficient distribution characteristics, and the thermal expansion coefficients of the lower confinement layer 101, the lower waveguide layer 102, the first electron spin state control layer 106a, and the second electron spin state control layer 106b have the following relationship:

[0048] The thermal expansion coefficient of the lower waveguide layer 102 is less than the thermal expansion coefficient of the second electron spin state control layer 106b, which is less than the thermal expansion coefficient of the first electron spin state control layer 106a and less than the thermal expansion coefficient of the lower confinement layer 101.

[0049] Furthermore, this embodiment also designs the thermal expansion coefficient distribution in the first electron spin state control layer 106a and the second electron spin state control layer 106b, specifically as follows:

[0050] The thermal expansion coefficient of the first electron spin-state modulation layer 106a is given by the function y5=E+F*x1e x1 Curve distribution;

[0051] The thermal expansion coefficient of the second electron spin state modulation layer 106b has the function y6 = G + e x2 +e -x2 Curve distribution.

[0052] In some optional embodiments, the lower confinement layer 101, the lower waveguide layer 102, the first electron spin state modulation layer 106a, and the second electron spin state modulation layer 106b also have conduction band effective state density distribution characteristics, and the conduction band effective state densities in the lower confinement layer 101, the lower waveguide layer 102, the first electron spin state modulation layer 106a, and the second electron spin state modulation layer 106b have the following relationship:

[0053] The effective density of states in the conduction band of the lower waveguide layer 102 is less than or equal to the effective density of states in the conduction band of the second electron spin state control layer 106b, which is less than or equal to the effective density of states in the conduction band of the first electron spin state control layer 106a, which is less than or equal to the effective density of states in the conduction band of the lower confinement layer 101.

[0054] Furthermore, this embodiment also designs the effective state density distribution of the thermal conduction band in the first electron spin state control layer 106a and the second electron spin state control layer 106b, specifically as follows:

[0055] The effective state density distribution of the conduction band of the first electron spin-controlled layer 106a has the function y7=H+J*x1 2 e x1 Curve distribution;

[0056] The effective state density distribution of the conduction band of the second electron spin state control layer 106b is y8=K+L*e x2 +M*x2 2 Curve distribution.

[0057] In the spontaneous polarization coefficient distribution, piezoelectric polarization coefficient distribution, thermal expansion coefficient distribution, and conduction band effective density of states distribution function of the first electron spin state control layer 106a, C≤A≤E≤H. In the spontaneous polarization coefficient distribution, piezoelectric polarization coefficient distribution, thermal expansion coefficient distribution, and conduction band effective density of states distribution function of the first electron spin state control layer 106a, g≤d≤G≤K.

[0058] In some optional embodiments, the first electron spin state control layer 106a and the second electron spin state control layer 106b are any one or any combination of GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, InGaN / GaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, InGaN / AlInGaN superlattice, GaN / AlGaN superlattice, GaN / AlInGaN superlattice, GaN / AlN superlattice, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAsN, AlInAs, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga2O3, and BN.

[0059] In some alternative embodiments, the thickness of the electron spin state modulation layer 106 is from 0.5 nm to 5000 nm.

[0060] In some alternative embodiments, the active layer 103 is a periodic structure composed of a well layer and a barrier layer, with a period number of 3 ≥ m ≥ 1.

[0061] The well layer is any one or any 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, and BN, with a thickness of 10 angstroms to 100 angstroms.

[0062] The barrier layer is any one or any 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, and BN, with a thickness of 10 angstroms to 150 angstroms.

[0063] In some optional embodiments, the lower confinement layer 101, the lower waveguide layer 102, the upper waveguide layer 104, and the upper confinement layer 105 are any one or any 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, and BN.

[0064] In some alternative embodiments, substrate 100 includes sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, sapphire / AlN composite substrate, and sapphire / SiN composite substrate. x Sapphire / SiO2 / SiN x The composite substrate, or any one of the following: magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2, and LiGaO2 composite substrate.

[0065] The table below compares the parameters of a conventional semiconductor laser device with the GaN-based compound semiconductor laser device proposed in this embodiment, including slope efficiency, threshold current density, optical power, and limiting factor, highlighting the differences between the two devices:

[0066]

[0067]

[0068] As can be seen, the GaN-based compound semiconductor laser element proposed in this embodiment improves slope efficiency, optical power and confinement factor, and reduces threshold current density compared with traditional semiconductor laser elements, showing significant advantages over traditional semiconductor laser elements.

[0069] 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 GaN-based compound semiconductor laser element comprising, in order from the bottom, a substrate, a lower cladding layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper cladding layer, characterized in that, The electronic spin state regulating layer is arranged between the lower limiting layer and the lower waveguide layer, and includes a first electronic spin state regulating layer and a second electronic spin state regulating layer, the first electronic spin state regulating layer is below the second electronic spin state regulating layer, the lower limiting layer, the lower waveguide layer, the first electronic spin state regulating layer and the second electronic spin state regulating layer all have piezoelectric polarization coefficient distribution characteristics, and the piezoelectric polarization coefficient of the lower waveguide layer is greater than the piezoelectric polarization coefficient of the second electronic spin state regulating layer, which is greater than the piezoelectric polarization coefficient of the first electronic spin state regulating layer, which is greater than the piezoelectric polarization coefficient of the lower limiting layer, the piezoelectric polarization coefficient of the first electronic spin state regulating layer has a function y1=A+Bx1 -a Curvilinear distribution, and a is an odd number greater than 1, x1 is the depth of the first electronic spin state regulating layer in the direction of the second electronic spin state regulating layer, the piezoelectric polarization coefficient of the second electronic spin state regulating layer has a function y2=bx2 2 +cx2+d curvilinear distribution, and b<0, x2 is the depth of the second electronic spin state regulating layer in the direction of the lower waveguide layer.

2. The GaN-based compound semiconductor laser device according to claim 1, characterized by The lower limiting layer, the lower waveguide layer, the first electron spin state regulation layer and the second electron spin state regulation layer all have spontaneous polarization coefficient distribution characteristics, and the spontaneous polarization coefficient of the lower waveguide layer is less than the spontaneous polarization coefficient of the second electron spin state regulation layer, which is less than the spontaneous polarization coefficient of the first electron spin state regulation layer, which is less than the spontaneous polarization coefficient of the lower limiting layer, the spontaneous polarization coefficient of the first electron spin state regulation layer has a function y3=C+D*k x1 Curvilinear distribution, and k>1, the spontaneous polarization coefficient of the second electron spin state regulation layer has a function y4=h*x2 2 +fx2+g curvilinear distribution, and h>0.

3. The GaN-based compound semiconductor laser device according to claim 2, characterized by The lower confining layer, the lower waveguide layer, the first electron spin state control layer and the second electron spin state control layer all have a thermal expansion coefficient distribution characteristic, and the thermal expansion coefficient of the lower waveguide layer ≤ the thermal expansion coefficient of the second electron spin state control layer ≤ the thermal expansion coefficient of the first electron spin state control layer ≤ the thermal expansion coefficient of the lower confining layer, the thermal expansion coefficient of the first electron spin state control layer has a function y5=E+F*x1e x1 curve distribution, the thermal expansion coefficient of the second electron spin state control layer has a function y6=G+e x2 +e -x2 curve distribution.

4. The GaN-based compound semiconductor laser device according to claim 3, characterized by The lower confinement layer, the lower waveguide layer, the first electron spin state regulation layer and the second electron spin state regulation layer all have conduction band effective state density distribution characteristics, and the conduction band effective state density of the lower waveguide layer is less than the conduction band effective state density of the second electron spin state regulation layer, which is less than the conduction band effective state density of the first electron spin state regulation layer, which is less than the conduction band effective state density of the lower confinement layer, and the conduction band effective state density distribution of the first electron spin state regulation layer has a function y7=H+J*x1 2 e x1 curve distribution, and the conduction band effective state density distribution of the second electron spin state regulation layer has a function y8=K+L*e x2 +M*x2 2 curve distribution.

5. The GaN-based compound semiconductor laser device according to claim 4, wherein In the spontaneous polarization coefficient distribution, piezoelectric polarization coefficient distribution, thermal expansion coefficient distribution, and conduction band effective state density distribution function of the first electronic spin state regulation layer, C≤A≤E≤H; In the spontaneous polarization coefficient distribution, piezoelectric polarization coefficient distribution, thermal expansion coefficient distribution, and conduction band effective state density distribution function of the second electronic spin state regulation layer, g≤d≤G≤K.

6. The GaN-based compound semiconductor laser device according to claim 1, characterized by The first electronic spin state regulation layer and the second electronic spin state regulation layer are any one or any combination of any one or any combination of GaN, InGaN, InN, AlInN, AlGaN, AlInGaN, AlN, InGaN / GaN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, InGaN / AlInN superlattice, GaN / AlGaN superlattice, GaN / AlInGaN superlattice, GaN / AlN superlattice, GaAs, GaP, InP, AlGaAs, AlInGaAs, AlGaInP, InGaAs, InGaAsN, AlInAs, AlInP, AlGaP, InGaP, GaSb, InSb, InAs, InAsSb, AlGaSb, AlSb, InGaSb, AlGaAsSb, InGaAsSb, SiC, Ga2O3, and BN.

7. The GaN-based compound semiconductor laser device according to claim 1, wherein The thickness of the electronic spin state regulation layer is 0.5 nm to 5000 nm.

8. The GaN-based compound semiconductor laser device according to claim 1, characterized by The active layer is a periodic structure composed of a well layer and a barrier layer, the number of periods is 3≥m≥1, the well layer is any one or any 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, and BN, and the thickness is 10 angstrom meters to 100 angstrom meters, the barrier layer is any one or any 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, and BN, and the thickness is 10 angstrom meters to 150 angstrom meters.

9. The GaN-based compound semiconductor laser device according to claim 1, wherein The lower confining layer, the lower waveguide layer, the upper waveguide layer, and the upper confining layer are any one or any combination of any one or any 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.

10. The GaN-based compound semiconductor laser device according to claim 1, characterized by The substrate comprises any one of sapphire, silicon, Ge, SiC, AIN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, sapphire / AIN composite substrate, sapphire / SiN x composite substrate, sapphire / SiO2 / SiN x composite substrate, magnesium-aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2, and LiGaO2 composite substrate.

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