A gallium nitride-based semiconductor laser with a hole burning suppression layer

Abstract

This invention proposes a gallium nitride-based semiconductor laser with a hole-burning suppression 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, and an upper confinement layer. This invention sets the distribution and variation trend of Al or In element concentrations in the hole-burning suppression layer, the upper confinement layer, the upper waveguide layer, and the lower waveguide layer, thereby controlling the uniformity of interface strain, the uniformity of interface Al element concentration distribution, and the interface quality of the laser structure. This improves the quantization of injected carrier energy, increases the carrier utilization rate in the injected active region, reduces the coupling time constant between electrons and photons in the active layer, reduces the number of interface states, and reduces the standing wave reduction caused by stimulated emission and the interaction between defects and interface states, as well as the population inversion distribution of standing wave interference particles excited by the laser resonator. This suppresses abrupt drops in the gain curve at any frequency position, suppresses the hole-burning effect, and improves slope efficiency.

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 hole burning suppression 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 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 suffer from the following problems: The number of inverted particles generated by the laser exhibits a frequency distribution. Due to non-uniform broadening and saturation intensity issues, the particle number drops sharply at a certain frequency. The particle number in local resonant cavity spaces (antinodes) is consumed, while local spaces (nodes) still exist. This phenomenon is called the "hole burning effect" in the particle number or gain curve. The inversion of the particle number distribution in the active layer is spatially non-uniform, as is the spatial distribution of radiative recombination carrier concentration. The inversion of the number of interfering particles excited within the resonant cavity further reduces the number of inverted particles, causing frequency hole burning in the local gain spectrum and resulting in spatial hole burning. The gain curve decreases at that laser frequency, making the laser spectrum wider and containing several modes in the emitted light wave. As the current increases, stimulated emission intensifies, and the carrier concentration at the center of the active region decreases, also causing spatial hole burning in the local gain distribution and reducing the gain-guided waveguide effect. Summary of the Invention

[0009] To address one of the aforementioned technical problems, the present invention provides a gallium nitride-based semiconductor laser with a hole burning suppression layer.

[0010] This invention provides a gallium nitride-based semiconductor laser with a hole-burning suppression 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, and an upper confinement layer. The Al element concentration of the electron blocking layer is greater than or equal to the Al element concentration of the upper confinement layer. The upper confinement layer includes a first upper confinement layer and a second upper confinement layer, with the first upper confinement layer located between the electron blocking layer and the upper waveguide layer, and the second upper confinement layer located above the electron blocking layer. The upper waveguide layer includes a first upper waveguide layer and a second upper waveguide layer, with the first upper waveguide layer located below the second upper waveguide layer. The In element concentration of the first upper waveguide layer is greater than or equal to the In element concentration of the second upper waveguide 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 upper waveguide layer. Below the second lower waveguide layer, the In element concentration of the first lower waveguide layer is less than or equal to the In element concentration of the second lower waveguide layer. A first hole-hole suppression layer is disposed between the first lower waveguide layer and the lower confinement layer, and a second hole-hole suppression layer is disposed between the second upper waveguide layer and the first upper confinement layer. The peak position of the Al element concentration in the first hole-hole suppression layer decreases at an angle of 60° to 90° towards the active layer. The peak position of the Al element concentration in the second hole-hole suppression layer decreases at an angle of 60° to 90° towards the active layer. The peak position of the Al element concentration in the first lower waveguide layer decreases at an angle of 15° to 60° towards the active layer. The peak position of the Al element concentration in the second upper waveguide layer decreases at an angle of 15° to 60° towards the active layer. The angles are tangent angles along the curve.

[0011] Preferably, the angle at which the peak position of the Al element concentration in the first lower waveguide layer decreases towards the active layer is less than the angle at which the peak position of the Al element concentration in the second upper waveguide layer decreases towards the active layer is less than the angle at which the peak position of the Al element concentration in the first hole burning suppression layer decreases towards the active layer is less than the angle at which the peak position of the Al element concentration in the second hole burning suppression layer decreases towards the active layer.

[0012] Preferably, the first upper confinement layer is an unintentionally doped layer, and the Mg doping concentration of the second upper confinement layer is 1E18cm⁻¹. -3 Up to 1E19cm -3 The Mg doping concentration of the electron blocking layer is 1E18cm⁻¹. -3 Up to 1E19cm -3 The Mg doping concentration of the electron blocking layer is greater than or equal to the Mg doping concentration of the second upper confinement layer and greater than or equal to the Mg doping concentration of the first upper confinement layer.

[0013] Preferably, the first hole burning suppression layer, the second hole burning suppression layer, the first lower waveguide layer, and the second upper waveguide layer all have refractive index characteristics;

[0014] The angle of increase of the refractive index valley position of the first hole burning suppression layer towards the active layer is α, 60°≤α≤90°;

[0015] The angle of increase of the refractive index valley position of the second hole burning suppression layer towards the active layer is β, 60°≤β≤90°;

[0016] The angle of increase of the refractive index valley of the first lower waveguide layer toward the active layer is γ, 10°≤γ≤60°;

[0017] The angle of increase of the refractive index valley of the second upper waveguide layer toward the active layer is θ, where 15°≤θ≤60°;

[0018] Where γ≤θ≤α≤β.

[0019] Preferably, the first hole burning suppression layer, the second hole burning suppression layer, the first lower waveguide layer, and the second upper waveguide layer all have elastic coefficient characteristics;

[0020] The angle of ascent from the valley of the elastic coefficient of the first hole burning suppression layer towards the active layer is:

[0021] The angle of rise of the valley position of the elastic coefficient of the second hole burning suppression layer towards the active layer is ω, 60°≤ω≤90°;

[0022] The angle of ascent of the valley position of the elastic coefficient of the first lower waveguide layer toward the active layer is δ, where 10°≤δ≤60°;

[0023] The angle of increase of the valley position of the elastic coefficient of the second upper waveguide layer towards the active layer is ψ, where 15°≤ψ≤60°;

[0024] in,

[0025] Preferably, the first hole burning suppression layer, the second hole burning suppression layer, the first lower waveguide layer, and the second upper waveguide layer all have thermal expansion coefficient characteristics;

[0026] The peak position of the thermal expansion coefficient of the first hole burning suppression layer decreases by an angle ε towards the active layer, where 60°≤ε≤90°;

[0027] The peak position of the thermal expansion coefficient of the second hole burning suppression layer decreases at an angle σ towards the active layer, where 60°≤σ≤90°;

[0028] The peak position of the thermal expansion coefficient of the first lower waveguide layer decreases by an angle μ towards the active layer, where 10°≤μ≤60°;

[0029] The peak position of the thermal expansion coefficient of the second upper waveguide layer decreases at an angle ρ towards the active layer, where 15°≤ρ≤60°.

[0030] Where μ≤ρ≤ε≤σ.

[0031] Preferably, the first hole burning suppression layer, the second hole burning suppression layer, the first lower waveguide layer, and the second upper waveguide layer all have thermal conductivity characteristics.

[0032] The peak position of the thermal conductivity of the first hole burning suppression layer decreases at an angle ζ towards the active layer, where 60°≤ζ≤90°;

[0033] The peak position of the thermal conductivity of the second hole burning suppression layer decreases at an angle χ towards the active layer, where 60°≤χ≤90°;

[0034] The peak position of the thermal conductivity of the first lower waveguide layer decreases at an angle τ towards the active layer, where 10°≤τ≤60°;

[0035] The peak position of the thermal conductivity of the second upper waveguide layer decreases at an angle κ towards the active layer, where 15°≤κ≤60°.

[0036] Where τ≤κ≤ζ≤χ.

[0037] Preferably, the first hole burning suppression layer, the second hole burning suppression layer, the first lower waveguide layer, and the second upper waveguide layer all have transverse sound velocity characteristics.

[0038] The peak position of the transverse sound velocity of the first hole burning suppression layer decreases at an angle υ towards the active layer, where 60°≤υ≤90°;

[0039] The peak position of the transverse sound velocity of the second hole burning suppression layer decreases at an angle of π towards the active layer, where 60°≤π≤90°;

[0040] The peak position of the transverse sound velocity in the first lower waveguide layer decreases by an angle λ towards the active layer, where 10°≤λ≤60°.

[0041] The peak position of the transverse sound velocity in the second upper waveguide layer decreases by an angle ν towards the active layer, where 15°≤ν≤60°.

[0042] Where λ≤ν≤υ≤π, 60°≤ω≤β≤π≤σ≤χ≤90°.

[0043] Preferably, both the first hole burning suppression layer and the second hole burning suppression layer have light hole effective mass distribution characteristics, peak velocity electric field distribution characteristics, conduction band effective state density distribution characteristics, electron effective mass distribution characteristics, and separation energy distribution characteristics.

[0044] The effective mass of light holes in the first hole-burning suppression layer has a curve distribution of function y1 = A + B * lnx1 / x1, and the effective mass of light holes in the second hole-burning suppression layer has a function y2 = C + D * e x2 / lnx2 curve distribution;

[0045] The peak velocity electric field of the first hole burning suppression layer has a function y3 = F + G * lnx1 / x1 curve distribution, and the peak velocity electric field of the second hole burning suppression layer has a function y4 = H + J * e x2 / lnx2 curve distribution;

[0046] The effective density of states in the conduction band of the first hole-burning suppression layer has a function y5 = K + L * lnx1 / x1, and the effective density of states in the conduction band of the second hole-burning suppression layer has a function y6 = M + N * e x2 / lnx2 curve distribution;

[0047] The effective electron mass of the first hole-burning suppression layer has a function y7 = P + Q * lnx1 / x1 curve distribution, and the effective electron mass of the second hole-burning suppression layer has a function y8 = R + S * e x2 / lnx2 curve distribution;

[0048] The separation energy of the first hole-burning suppression layer has a function y9 = T + U*lnx1 / x1 curve distribution, and the separation energy of the second hole-burning suppression layer has a function y 10 =V+W*e x2 / lnx2 curve distribution;

[0049] Where x1 is the depth of the first hole-burning suppression layer towards the second lower waveguide layer, x2 is the depth of the second hole-burning suppression layer towards the first upper confinement layer, P≤A≤T≤F≤K, R≤C≤V≤H≤M.

[0050] Preferably, the first hole burning suppression layer and the second hole burning suppression layer are any one or any combination of InGaN, InN, AlInGaN, GaN, AlGaN, InGaN / GaN superlattice, InGaN / AlInN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, GaN / AlInGaN superlattice, GaN / AlInGaN superlattice, GaN / AlGaN superlattice, InGaN / InGaN superlattice, AlInGaN / AlInGaN superlattice, or any combination with GaN.

[0051] 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, BN, and diamond. Combinations with a thickness of 10 angstroms to 150 angstroms; 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, BN, and diamond, with a thickness of 10 angstroms to 200 angstroms.

[0052] Preferably, the lower confinement layer, lower waveguide layer, upper waveguide layer, electron blocking 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, BN, and diamond.

[0053] Preferably, the substrate is a single-crystal substrate, such as sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, Mo, TiW, CuW, Cu, sapphire / AlN composite substrate, diamond, or sapphire / SiN composite substrate. x Sapphire / SiO2 / SiN x Composite substrate, sapphire / SiN x Any one of the following: SiO2 composite substrate, magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

[0054] The beneficial effects of this invention are as follows: This invention sets a hole burning suppression layer in a gallium nitride-based semiconductor laser, and sets the distribution state and trend of Al or In element concentration in the hole burning suppression layer, upper confinement layer, upper waveguide layer, and lower waveguide layer. This controls the uniformity of interface strain, the uniformity of interface Al element concentration distribution, and interface quality of the laser structure, improves the quantization of injected carrier energy, improves the carrier utilization rate of injected active region, reduces the coupling time constant of electrons and photons in active layer, reduces the number of interface states, reduces the reduction of standing wave caused by stimulated emission and interaction with defects and interface states, and reduces the population inversion distribution of standing wave interference particles excited by laser resonator. This suppresses the abrupt drop at any frequency position of the gain curve, suppresses the hole burning effect, and improves slope efficiency. Attached Figure Description

[0055] 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:

[0056] Figure 1 This is a schematic diagram of the structure of a gallium nitride-based semiconductor laser with a hole burning suppression layer according to an embodiment of the present invention;

[0057] Figure 2 This is a SIMS secondary ion mass spectrum of a gallium nitride-based semiconductor laser with a hole burning suppression layer as described in an embodiment of the present invention.

[0058] Figure label:

[0059] 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. Hole burning suppression layer.

[0060] 102a, First lower waveguide layer; 102b, Second lower waveguide layer; 104a, First upper waveguide layer; 104b, Second upper waveguide layer; 106a, First upper confinement layer; 106b, Second upper confinement layer; 107a, First hole burning suppression layer; 107b, Second hole burning suppression layer. Detailed Implementation

[0061] 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.

[0062] like Figure 1 and Figure 2 As shown, this embodiment proposes a gallium nitride-based semiconductor laser with a hole-hole suppression layer, comprising, 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, an electron blocking layer 105, and an upper confinement layer 106. A hole-hole suppression layer 107 is also provided in this gallium nitride-based semiconductor laser with a hole-hole suppression layer.

[0063] Specifically, in this embodiment, the gallium nitride-based semiconductor laser with a hole-burning suppression layer is provided from bottom to top as follows: substrate 100, lower confinement layer 101, lower waveguide layer 102, active layer 103, upper waveguide layer 104, electron blocking layer 105, and upper confinement layer 106. The upper confinement layer 106 includes a first upper confinement layer 106a and a second upper confinement layer 106b, with the first upper confinement layer 106a located below the second upper confinement layer 106b. The electron blocking layer 105 is located between the first upper confinement layer 106a and the second upper confinement layer 106b. The upper waveguide layer 104 includes a first upper waveguide layer 104a and a second upper waveguide layer 104b, with the first upper waveguide layer 104a located below the second upper waveguide layer 104b. A first hole-burning suppression layer 107a is disposed between the first lower waveguide layer 102a and the lower confinement layer 101. A second hole burning suppression layer 107b is disposed between the second upper waveguide layer 104b and the first upper confinement layer 106a. The first hole burning suppression layer 107a and the second hole burning suppression layer 107b constitute the hole burning suppression layer 107.

[0064] In this embodiment, the lower waveguide layer 102, the upper waveguide layer 104, the electron blocking layer 105, the upper confinement layer 106, and the hole burning suppression layer 107, as well as the layers among them, all have certain Al element concentration distribution characteristics or In element concentration distribution characteristics.

[0065] Specifically, between the electron blocking layer 105 and the upper confinement layer 106, the Al element concentration of the electron blocking layer 105 is greater than or equal to the Al element concentration of the upper confinement layer 106. Between the first upper waveguide layer 104a and the second upper waveguide layer 104b, the In element concentration of the first upper waveguide layer 104a is greater than or equal to the In element concentration of the second upper waveguide layer 104b. Between the first lower waveguide layer 102a and the second lower waveguide layer 102b, the In element concentration of the first lower waveguide layer 102a is less than or equal to the In element concentration of the second lower waveguide layer 102b.

[0066] The peak positions of Al element concentration in the first hole hole burning suppression layer 107a, the second hole hole burning suppression layer 107b, the first lower waveguide layer 102a, and the second upper waveguide layer 104b show a certain trend of change towards the active layer 103, specifically as follows:

[0067] The peak position of Al element concentration in the first hole burning suppression layer 107a shows an abrupt decreasing trend towards the active layer 103.

[0068] The peak position of Al element concentration in the second hole burning suppression layer 107b shows an abrupt decreasing trend towards the active layer 103.

[0069] The peak position of Al element concentration in the first lower waveguide layer 102a shows a gradual decreasing trend towards the active layer 103.

[0070] The peak position of Al element concentration in the second upper waveguide layer 104b shows a gradual decreasing trend towards the active layer 103.

[0071] More specifically, the peak position of the Al element concentration in the first hole burning suppression layer 107a decreases by an angle of 60° to 90° towards the active layer 103; the peak position of the Al element concentration in the second hole burning suppression layer 107b decreases by an angle of 60° to 90° towards the active layer 103; the peak position of the Al element concentration in the first lower waveguide layer 102a decreases by an angle of 15° to 60° towards the active layer 103; and the peak position of the Al element concentration in the second upper waveguide layer 104b decreases by an angle of 15° to 60° towards the active layer 103. Here, the angle is the tangent tilt angle along the curve.

[0072] In this embodiment, a hole burning suppression layer 107 is provided in a gallium nitride-based semiconductor laser, and the distribution and trend of Al or In element concentration in the hole burning suppression layer 107, upper confinement layer 106, upper waveguide layer 104, and lower waveguide layer 102 are set. This controls the uniformity of interface strain, the uniformity of interface Al element concentration distribution, and interface quality of the laser structure, improves the quantization of injected carrier energy, improves the carrier utilization rate of injected active region, reduces the coupling time constant of electrons and photons in active layer 103, reduces the number of interface states, reduces the standing wave reduction caused by stimulated emission and the interaction of defects and interface states, and reduces the population inversion distribution of standing wave interference particles excited by laser resonator, thereby suppressing the abrupt drop at any frequency position of the gain curve, suppressing the hole burning effect, and improving slope efficiency.

[0073] Furthermore, in this embodiment, the following relationships also exist between the falling angle of the peak position of the Al element concentration in the first lower waveguide layer 102a towards the active layer 103, the falling angle of the peak position of the Al element concentration in the second upper waveguide layer 104b towards the active layer 103, the falling angle of the peak position of the Al element concentration in the first hole burning suppression layer 107a towards the active layer 103, and the falling angle of the peak position of the Al element concentration in the second hole burning suppression layer 107b towards the active layer 103:

[0074] The angle at which the peak position of the Al element concentration in the first lower waveguide layer 102a decreases towards the active layer 103 is less than the angle at which the peak position of the Al element concentration in the second upper waveguide layer 104b decreases towards the active layer 103 is less than the angle at which the peak position of the Al element concentration in the first hole burning suppression layer 107a decreases towards the active layer 103 is less than the angle at which the peak position of the Al element concentration in the second hole burning suppression layer 107b decreases towards the active layer 103.

[0075] In some optional embodiments, the first upper confinement layer 106a, the second upper confinement layer 106b, and the electron blocking layer 105 also have a certain Mg doping concentration relationship. Specifically, the first upper confinement layer 106a is an unintentionally doped layer, and the Mg doping concentration of the second upper confinement layer 106b is 1E18cm⁻¹. -3 Up to 1E19cm -3 The Mg doping concentration of electron blocking layer 105 is 1E18cm. -3 Up to 1E19cm -3 The Mg doping concentration of the electron blocking layer 105 is greater than or equal to the Mg doping concentration of the second upper confinement layer 106b, which is greater than or equal to the Mg doping concentration of the first upper confinement layer 106a.

[0076] In some optional embodiments, the first hole burning suppression layer 107a, the second hole burning suppression layer 107b, the first lower waveguide layer 102a, and the second upper waveguide layer 104b all have refractive index characteristics, and the first hole burning suppression layer 107a, the second hole burning suppression layer 107b, the first lower waveguide layer 102a, and the second upper waveguide layer 104b also have a certain refractive index variation trend, specifically manifested as follows:

[0077] The refractive index of the first hole burning suppression layer 107a shows an abrupt upward trend towards the active layer 103, with the valley position of the refractive index increasing abruptly.

[0078] The refractive index valley of the second hole burning suppression layer 107b shows an abrupt upward trend toward the active layer 103.

[0079] The refractive index of the first lower waveguide layer 102a shows a gradual upward trend towards the active layer 103.

[0080] The refractive index of the second upper waveguide layer 104b shows a gradual upward trend towards the active layer 103, with the valley position gradually increasing.

[0081] Specifically, the angle of increase from the refractive index valley of the first hole burning suppression layer 107a towards the active layer 103 is α, 60°≤α≤90°; the angle of increase from the refractive index valley of the second hole burning suppression layer 107b towards the active layer 103 is β, 60°≤β≤90°; the angle of increase from the refractive index valley of the first lower waveguide layer 102a towards the active layer 103 is γ, 10°≤γ≤60°; and the angle of increase from the refractive index valley of the second upper waveguide layer 104b towards the active layer 103 is θ, 15°≤θ≤60°; where γ≤θ≤α≤β.

[0082] In some optional embodiments, the first hole burning suppression layer 107a, the second hole burning suppression layer 107b, the first lower waveguide layer 102a, and the second upper waveguide layer 104b all possess elastic coefficient characteristics. Furthermore, the first hole burning suppression layer 107a, the second hole burning suppression layer 107b, the first lower waveguide layer 102a, and the second upper waveguide layer 104b also exhibit a certain elastic coefficient variation trend, specifically manifested as follows:

[0083] The valley position of the elastic coefficient of the first hole burning suppression layer 107a shows an abrupt upward trend toward the active layer 103.

[0084] The valley position of the elastic coefficient of the second hole burning suppression layer 107b shows an abrupt upward trend toward the active layer 103.

[0085] The location of the valley of the elastic coefficient of the first lower waveguide layer 102a shows a gradual upward trend toward the active layer 103.

[0086] The location of the valley of the elastic coefficient of the second upper waveguide layer 104b shows a gradual upward trend towards the active layer 103.

[0087] Specifically, the angle of ascent from the valley of the elastic modulus of the first hole burning suppression layer 107a toward the active layer 103 is... The angle of increase of the valley position of the elastic coefficient of the second hole burning suppression layer 107b towards the active layer 103 is ω, 60°≤ω≤90°; the angle of increase of the valley position of the elastic coefficient of the first lower waveguide layer 102a towards the active layer 103 is δ, 10°≤δ≤60°; the angle of increase of the valley position of the elastic coefficient of the second upper waveguide layer 104b towards the active layer 103 is ψ, 15°≤ψ≤60°; where,

[0088] In some optional embodiments, the first hole burning suppression layer 107a, the second hole burning suppression layer 107b, the first lower waveguide layer 102a, and the second upper waveguide layer 104b all have thermal expansion coefficient characteristics. Furthermore, the first hole burning suppression layer 107a, the second hole burning suppression layer 107b, the first lower waveguide layer 102a, and the second upper waveguide layer 104b also exhibit a certain trend in the variation of their thermal expansion coefficients, specifically manifested as follows:

[0089] The peak position of the thermal expansion coefficient of the first hole burning suppression layer 107a shows an abrupt decreasing trend toward the active layer 103.

[0090] The peak position of the thermal expansion coefficient of the second hole burning suppression layer 107b shows an abrupt decreasing trend toward the active layer 103.

[0091] The peak position of the thermal expansion coefficient of the first lower waveguide layer 102a shows a gradual decreasing trend towards the active layer 103.

[0092] The peak position of the thermal expansion coefficient of the second upper waveguide layer 104b shows a gradual decreasing trend towards the active layer 103.

[0093] Specifically, the peak position of the thermal expansion coefficient of the first hole burning suppression layer 107a decreases by an angle ε towards the active layer 103, where 60°≤ε≤90°; the peak position of the thermal expansion coefficient of the second hole burning suppression layer 107b decreases by an angle σ towards the active layer 103, where 60°≤σ≤90°; the peak position of the thermal expansion coefficient of the first lower waveguide layer 102a decreases by an angle μ towards the active layer 103, where 10°≤μ≤60°; and the peak position of the thermal expansion coefficient of the second upper waveguide layer 104b decreases by an angle ρ towards the active layer 103, where 15°≤ρ≤60°; where μ≤ρ≤ε≤σ.

[0094] In some optional embodiments, the first hole burning suppression layer 107a, the second hole burning suppression layer 107b, the first lower waveguide layer 102a, and the second upper waveguide layer 104b all possess thermal conductivity characteristics. Furthermore, the first hole burning suppression layer 107a, the second hole burning suppression layer 107b, the first lower waveguide layer 102a, and the second upper waveguide layer 104b also exhibit a certain trend in thermal conductivity variation, specifically manifested as follows:

[0095] The peak position of the thermal conductivity of the first hole burning suppression layer 107a shows an abrupt decreasing trend toward the active layer 103.

[0096] The peak position of the thermal conductivity of the second hole burning suppression layer 107b shows an abrupt decreasing trend toward the active layer 103.

[0097] The peak position of the thermal conductivity of the first lower waveguide layer 102a shows a gradual decreasing trend towards the active layer 103.

[0098] The peak position of the thermal conductivity of the second upper waveguide layer 104b shows a gradual decreasing trend towards the active layer 103.

[0099] Specifically, the peak position of the thermal conductivity of the first hole burning suppression layer 107a decreases by an angle ζ towards the active layer 103, where 60°≤ζ≤90°; the peak position of the thermal conductivity of the second hole burning suppression layer 107b decreases by an angle χ towards the active layer 103, where 60°≤χ≤90°; the peak position of the thermal conductivity of the first lower waveguide layer 102a decreases by an angle τ towards the active layer 103, where 10°≤τ≤60°; and the peak position of the thermal conductivity of the second upper waveguide layer 104b decreases by an angle κ towards the active layer 103, where 15°≤κ≤60°; where τ≤κ≤ζ≤χ.

[0100] In some optional embodiments, the first hole burning suppression layer 107a, the second hole burning suppression layer 107b, the first lower waveguide layer 102a, and the second upper waveguide layer 104b all have transverse sound velocity characteristics. Furthermore, the first hole burning suppression layer 107a, the second hole burning suppression layer 107b, the first lower waveguide layer 102a, and the second upper waveguide layer 104b also exhibit a certain transverse sound velocity variation trend, specifically manifested as follows:

[0101] The peak position of the transverse sound velocity of the first hole burning suppression layer 107a shows an abrupt decreasing trend towards the active layer 103.

[0102] The peak position of the transverse sound velocity in the second hole burning suppression layer 107b shows an abrupt decreasing trend towards the active layer 103.

[0103] The peak position of the transverse sound velocity in the first lower waveguide layer 102a shows a gradually decreasing trend towards the active layer 103.

[0104] The peak position of the transverse sound velocity in the second upper waveguide layer 104b shows a gradual decreasing trend towards the active layer 103.

[0105] Specifically, the peak position of the transverse sound velocity of the first hole burning suppression layer 107a decreases by an angle υ towards the active layer 103, where 60°≤υ≤90°; the peak position of the transverse sound velocity of the second hole burning suppression layer 107b decreases by an angle π towards the active layer 103, where 60°≤π≤90°; the peak position of the transverse sound velocity of the first lower waveguide layer 102a decreases by an angle λ towards the active layer 103, where 10°≤λ≤60°; and the peak position of the transverse sound velocity of the second upper waveguide layer 104b decreases by an angle ν towards the active layer 103, where 15°≤ν≤60°; where λ≤ν≤υ≤π. 60°≤ω≤β≤π≤σ≤χ≤90°.

[0106] In this embodiment, by setting the distribution changes of refractive index, elastic coefficient, thermal expansion coefficient, thermal conductivity, and transverse sound velocity in the first hole burning suppression layer 107a, the second hole burning suppression layer 107b, the first lower waveguide layer 102a, and the second upper waveguide layer 104b, the thermal conductivity of the laser and the interfaces of each epitaxial layer is improved, the internal heat accumulation is reduced, the temperature rise effect of the active layer 103 is reduced, the Stokes frequency shift loss caused by the photon energy difference between the pump light and the oscillating light is suppressed, and the phonon transport efficiency is enhanced. This improves the uniformity of the interface thermal stress distribution of the spatial burning suppression layer and reduces waste heat accumulation. It also reduces the spatial burning effect caused by the large reduction in the number of inverted particles due to the temperature rise and thermal stress of the active layer 103, which causes frequency burning in the local gain spectrum, and improves the linearity of the laser gain curve.

[0107] In some optional embodiments, both the first hole burning suppression layer 107a and the second hole burning suppression layer 107b possess light hole effective mass distribution characteristics, peak velocity electric field distribution characteristics, conduction band effective density of states distribution characteristics, electron effective mass distribution characteristics, and separation energy distribution characteristics, as specifically manifested below:

[0108] (1) Effective mass distribution of light holes

[0109] The effective mass of light holes in the first hole burning suppression layer 107a has a function y1=A+B*lnx1 / x1 curve distribution;

[0110] The effective mass of light holes in the second hole burning suppression layer 107b has a function y2 = C + D*e x2 / lnx2 curve distribution;

[0111] (2) Peak velocity electric field distribution

[0112] The peak velocity electric field of the first hole burning suppression layer 107a has a function y3=F+G*lnx1 / x1 curve distribution;

[0113] The peak velocity electric field of the second hole burning suppression layer 107b has the function y4=H+J*e x2 / lnx2 curve distribution;

[0114] (3) Characteristics of effective state density distribution in conduction band

[0115] The effective density of states in the conduction band of the first hole burning suppression layer 107a has a function y5=K+L*lnx1 / x1 curve distribution;

[0116] The effective density of states in the conduction band of the second hole burning suppression layer 107b has the function y6=M+N*e x2 / lnx2 curve distribution;

[0117] (4) Effective electron mass distribution

[0118] The effective electron mass of the first hole burning suppression layer 107a has a function y7=P+Q*lnx1 / x1 curve distribution;

[0119] The effective electron mass of the second hole-burning suppression layer 107b has the function y8=R+S*e x2 / lnx2 curve distribution;

[0120] (5) Separation energy distribution

[0121] The separation energy of the first hole burning suppression layer 107a has a function y9=T+U*lnx1 / x1 curve distribution;

[0122] The separation energy of the second hole burning suppression layer 107b has a function y 10 =V+W*e x2 / lnx2 curve distribution;

[0123] Where x1 is the depth of the first hole burning suppression layer 107a toward the second lower waveguide layer 102b, x2 is the depth of the second hole burning suppression layer 107b toward the first upper confinement layer 106a, P≤A≤T≤F≤K, R≤C≤V≤H≤M.

[0124] This embodiment designs the effective mass distribution of light holes, peak velocity electric field distribution, effective density of states distribution of conduction band, effective mass distribution of electrons, and separation energy distribution in the first hole burning suppression layer 107a and the second hole burning suppression layer 107b. This design can improve the symmetry of conduction band and hole band, enhance the stability of population inversion and the uniformity of electron-hole wave function distribution, reduce the spatial and interface non-uniformity of population inversion in the active layer 103, and improve the spatial and interface non-uniformity of carrier concentration distribution of radiative recombination. As the laser's stimulated emission increases with rising current, the carrier concentration at the center of the active region remains continuously stable, suppressing the problem of sudden decrease in carrier concentration, thereby suppressing the spatial burning effect of the laser.

[0125] In some optional embodiments, the first hole burning suppression layer 107a and the second hole burning suppression layer 107b are any one or any combination of InGaN, InN, AlInGaN, GaN, AlGaN, InGaN / GaN superlattice, InGaN / AlInN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, GaN / AlInGaN superlattice, GaN / AlInN superlattice, GaN / AlGaN superlattice, InGaN / InGaN superlattice, AlInGaN / AlInGaN superlattice, or any combination of GaN.

[0126] In some alternative embodiments, the active layer 103 is a periodic structure composed of a well layer and a barrier layer, with the number of periods being 3≥m≥1, where m can be 1, 2, or 3.

[0127] Specifically, 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, BN, and diamond, with a thickness of 10 angstroms to 150 angstroms.

[0128] 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, BN, and diamond, with a thickness of 10 angstroms to 200 angstroms.

[0129] Preferably, the lower confinement layer 101, the lower waveguide layer 102, the upper waveguide layer 104, the electron blocking layer 105, and the upper confinement layer 106 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, BN, and diamond.

[0130] Preferably, the substrate 100 is a single-crystal substrate, which is sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, Mo, TiW, CuW, Cu, sapphire / AlN composite substrate, diamond, or sapphire / SiN composite substrate. x Sapphire / SiO2 / SiN x Composite substrate, sapphire / SiN x Any one of the following: SiO2 composite substrate, magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

[0131] The table below compares the parameters of a conventional semiconductor laser and the gallium nitride-based semiconductor laser with a hole-burning suppression layer proposed in this embodiment, including hole-burning current, hole-burning probability, and slope efficiency, showing the differences between the conventional semiconductor laser and the gallium nitride-based semiconductor laser with a hole-burning suppression layer proposed in this embodiment:

[0132]

[0133] As can be seen, the gallium nitride-based semiconductor laser with a hole burning suppression layer proposed in this embodiment improves the hole burning current and slope efficiency and reduces the hole burning probability compared with traditional semiconductor lasers, showing significant advantages over traditional semiconductor lasers.

[0134] 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 having a hole burning suppression 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, and an upper confinement layer, characterized in that, The Al element concentration of the electron blocking layer is greater than or equal to the Al element concentration of the upper limiting layer, the upper limiting layer includes a first upper limiting layer and a second upper limiting layer, the first upper limiting layer is located between the electron blocking layer and the upper waveguide layer, the second upper limiting layer is located above the electron blocking layer, the upper waveguide layer includes a first upper waveguide layer and a second upper waveguide layer, the first upper waveguide layer is located below the second upper waveguide layer, the In element concentration of the first upper waveguide layer is greater than or equal to the In element concentration of the second upper waveguide layer, 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 In element concentration of the first lower waveguide layer is less than or equal to the In element concentration of the second lower waveguide layer, a first hole burning inhibition layer is arranged between the first lower waveguide layer and the lower limiting layer, a second hole burning inhibition layer is arranged between the second upper waveguide layer and the first upper limiting layer, the falling angle of the peak position of the Al element concentration of the first hole burning inhibition layer to the active layer direction is 60° to 90°, the falling angle of the peak position of the Al element concentration of the second hole burning inhibition layer to the active layer direction is 60° to 90°, the falling angle of the peak position of the Al element concentration of the first lower waveguide layer to the active layer direction is 15° to 60°, the falling angle of the peak position of the Al element concentration of the second upper waveguide layer to the active layer direction is 15° to 60°, and the angle is the inclination angle of the tangent line along the curve.

2. The gallium nitride-based semiconductor laser having a hole burning suppression layer according to claim 1, characterized by, The falling angle of the peak position of the Al element concentration of the first lower waveguide layer to the active layer direction is less than or equal to the falling angle of the peak position of the Al element concentration of the second upper waveguide layer to the active layer direction, which is less than or equal to the falling angle of the peak position of the Al element concentration of the first hole burning inhibition layer to the active layer direction, which is less than or equal to the falling angle of the peak position of the Al element concentration of the second hole burning inhibition layer to the active layer direction.

3. The gallium nitride-based semiconductor laser having a hole burning suppression layer according to claim 1, characterized by, The first upper confinement layer is an unintentionally doped layer, and the Mg doping concentration of the second upper confinement layer is 1E18 cm -3 to 1E19 cm -3 The Mg doping concentration of the electron blocking layer is 1E18 cm -3 to 1E19 cm -3 The Mg doping concentration of the electron blocking layer is ≥ the Mg doping concentration of the second upper confinement layer ≥ the Mg doping concentration of the first upper confinement layer.

4. The gallium nitride-based semiconductor laser having a hole burning suppression layer according to claim 1, characterized by The first hole burning inhibition layer, the second hole burning inhibition layer, the first lower waveguide layer, and the second upper waveguide layer all have refractive index characteristics; The rising angle of the valley position of the refractive index of the first hole burning inhibition layer to the active layer direction is α, 60°≤α≤90°; The rising angle of the valley position of the refractive index of the second hole burning inhibition layer to the active layer direction is β, 60°≤β≤90°; The rising angle of the valley position of the refractive index of the first lower waveguide layer to the active layer direction is γ, 10°≤γ≤60°; The rising angle of the valley position of the refractive index of the second upper waveguide layer to the active layer direction is θ, 15°≤θ≤60°; Wherein, γ≤θ≤α≤β.

5. The gallium nitride-based semiconductor laser having a hole burning suppression layer according to claim 4, characterized by The first hole burning inhibition layer, the second hole burning inhibition layer, the first lower waveguide layer, and the second upper waveguide layer all have elastic coefficient characteristics; The angle of rise of the valley position of the elastic coefficient of the first hole burning inhibition layer in the direction of the active layer is The rising angle of the valley position of the elastic coefficient of the second hole burning inhibition layer to the active layer direction is ω, 60°≤ω≤90°; The rising angle of the valley position of the elastic coefficient of the first lower waveguide layer to the active layer direction is δ, 10°≤δ≤60°; An ascending angle of a valley position of the elastic coefficient of the second upper waveguide layer to the active layer direction is ψ, 15°≤ψ≤60°; wherein, 6. The gallium nitride-based semiconductor laser having a hole burning suppression layer according to claim 5, characterized by, The first hole burning inhibition layer, the second hole burning inhibition layer, the first lower waveguide layer, and the second upper waveguide layer all have a thermal expansion coefficient characteristic; A descending angle of a peak position of the thermal expansion coefficient of the first hole burning inhibition layer to the active layer direction is ε, 60°≤ε≤90°; A descending angle of a peak position of the thermal expansion coefficient of the second hole burning inhibition layer to the active layer direction is σ, 60°≤σ≤90°; A descending angle of a peak position of the thermal expansion coefficient of the first lower waveguide layer to the active layer direction is μ, 10°≤μ≤60°; A descending angle of a peak position of the thermal expansion coefficient of the second upper waveguide layer to the active layer direction is ρ, 15°≤ρ≤60°; μ≤ρ≤ε≤σ.

7. The gallium nitride-based semiconductor laser having a hole burning suppression layer according to claim 6, characterized by, The first hole burning inhibition layer, the second hole burning inhibition layer, the first lower waveguide layer, and the second upper waveguide layer all have a thermal conductivity characteristic; A descending angle of a peak position of the thermal conductivity of the first hole burning inhibition layer to the active layer direction is ζ, 60°≤ζ≤90°; A descending angle of a peak position of the thermal conductivity of the second hole burning inhibition layer to the active layer direction is χ, 60°≤χ≤90°; A descending angle of a peak position of the thermal conductivity of the first lower waveguide layer to the active layer direction is τ, 10°≤τ≤60°; A descending angle of a peak position of the thermal conductivity of the second upper waveguide layer to the active layer direction is κ, 15°≤κ≤60°; τ≤κ≤ζ≤χ.

8. The gallium nitride-based semiconductor laser having a hole burning suppression layer according to claim 7, characterized by, The first hole burning inhibition layer, the second hole burning inhibition layer, the first lower waveguide layer, and the second upper waveguide layer all have a transverse acoustic speed characteristic; A descending angle of a peak position of the transverse acoustic speed of the first hole burning inhibition layer to the active layer direction is υ, 60°≤υ≤90°; A descending angle of a peak position of the transverse acoustic speed of the second hole burning inhibition layer to the active layer direction is π, 60°≤π≤90°; A descending angle of a peak position of the transverse acoustic speed of the first lower waveguide layer to the active layer direction is λ, 10°≤λ≤60°; A descending angle of a peak position of the transverse acoustic speed of the second upper waveguide layer to the active layer direction is ν, 15°≤ν≤60°; where λ < v < u < π, 60° < ω < β < π < σ < χ < 90°.

9. The gallium nitride-based semiconductor laser having a hole burning suppression layer according to Claim 1, characterized by, The first hole burning inhibition layer and the second hole burning inhibition layer both have a light hole effective mass distribution characteristic, a peak rate electric field distribution characteristic, a conduction band effective state density distribution characteristic, an electron effective mass distribution characteristic, and a separation energy distribution characteristic; The light hole effective mass of the first hole burning inhibition layer has a function y1=A+B*lnx1 / x1 curve distribution, and the light hole effective mass of the second hole burning inhibition layer has a function y2=C+D*e x2 / lnx2 curve distribution. The peak rate electric field of the first hole burn hole suppression layer has a function y3=F+G*lnx1 / x1 curve distribution, the peak rate electric field of the second hole burn hole suppression layer has a function y4=H+J*e x2 / lnx2 curve distribution; The conduction band effective state density of the first hole burning inhibition layer has a curve distribution of function y5=K+L*lnx1 / x1, and the conduction band effective state density of the second hole burning inhibition layer has a curve distribution of function y6=M+N*e x2 lnx2; The effective mass of the electrons of the first hole burning inhibition layer has a curve distribution of function y7 = P + Q*lnx1 / x1, and the effective mass of the electrons of the second hole burning inhibition layer has a curve distribution of function y8 = R + S*e x2 / lnx2; The separation energy of the first hole burn hole suppression layer has a function y9 = T + U * In x1 / x1 curve distribution, and the separation energy of the second hole burn hole suppression layer has a function y 10 = V + W * e x2 / ln x2 curve distribution; Wherein, x1 is the depth of the first hole burning inhibition layer to the second lower waveguide layer direction, x2 is the depth of the second hole burning inhibition layer to the first upper limiting layer direction, P≤A≤T≤F≤K, R≤C≤V≤H≤M.

10. The gallium nitride-based semiconductor laser having a hole burning suppression layer according to Claim 1, characterized by, The first and second hole burning inhibition layers are any one or any combination of InGaN, InN, AlInGaN, GaN, AlGaN, InGaN / GaN superlattice, InGaN / AlInN superlattice, InGaN / AlGaN superlattice, InGaN / AlInGaN superlattice, GaN / AlInGaN superlattice, GaN / AlInN superlattice, GaN / AlGaN superlattice, InGaN / InGaN superlattice, AlInGaN / AlInGaN superlattice, or any combination with GaN; 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, BN, diamond, and the thickness is 10 angstrom meters to 150 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, BN, diamond, and the thickness is 10 angstrom meters to 200 angstrom meters; The lower confinement layer, lower waveguide layer, upper waveguide layer, electron blocking 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, BN, diamond. The substrate is a single crystal substrate, which is any one of sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, Mo, TiW, CuW, Cu, sapphire / AlN composite substrate, diamond, sapphire / SiN x , sapphire / SiO2 / SiN x composite substrate, sapphire / SiN x / SiO2 composite substrate, magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2, and LiGaO2 composite substrate.

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