GaN-based semiconductor laser element

Abstract

The GaN-based semiconductor laser element comprises a substrate, a lower limiting layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper limiting layer which are sequentially arranged from bottom to top, and a Bloch-Flory oscillation layer is arranged between the lower waveguide layer and the active layer. The Bloch-Flokey oscillation layer has thermal conductivity distribution characteristics and dielectric constant distribution characteristics, the thermal conductivity of the Bloch-Flokey oscillation layer has a curve distribution of a function y1 = M + Uex + sinx, and the dielectric constant of the Bloch-Flokey oscillation layer has a curve distribution of a function y2 = N + Acos (Bx + C). According to the invention, the performance of the GaN-based semiconductor laser element can be improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor optoelectronic devices, and in particular to a GaN-based semiconductor laser element. Background Art

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

[0003] There are big differences between lasers and nitride semiconductor light-emitting diodes:

[0004] 1) Laser is generated by stimulated radiation of carriers, the spectrum half-width is small, the brightness is very high, and the output power of a single laser can be in the W level, while nitride semiconductor light-emitting diodes are spontaneously radiated, and the output power of a single light-emitting diode is in the mW level;

[0005] 2) The current density of the laser reaches KA / cm2, which is more than 2 orders of magnitude higher than that of nitride light-emitting diodes, resulting in stronger electron leakage, more serious Auger recombination, stronger polarization effect, more serious electron-hole mismatch, and more serious efficiency attenuation Droop effect;

[0006] 3) The spontaneous transition radiation of the light-emitting diode is incoherent light that transitions from a high energy level to a low energy level without any external influence, while the laser is stimulated transition radiation, and the energy of the induced photon should be equal to the difference in the energy level of the electron transition, producing the same coherent light as the photon and the induced photon;

[0007] 4) Different principles: When an external voltage is applied to a light-emitting diode, electron holes jump to a quantum well or a pn junction to generate radiative recombination light, while a laser can only emit when the lasing conditions are met. The carrier distribution in the active region must be reversed, and the stimulated radiation light oscillates back and forth in the resonant cavity. The propagation in the gain medium amplifies the light, and the threshold condition is met so that the gain is greater than the loss, and finally the laser is output.

[0008] Nitride semiconductor lasers have the following problems:

[0009] 1) The activation energy of the Mg acceptor of the p-type semiconductor is large, the ionization efficiency is low, the hole concentration is much lower than the electron concentration, the hole mobility is much lower than the electron mobility, and the quantum well polarization electric field increases the hole injection barrier, the holes overflow the active layer, and other problems. The hole injection is uneven and the efficiency is low, resulting in serious asymmetric mismatch between electrons and holes in the quantum well, electron leakage and carrier delocalization, more difficult hole transport in the quantum well, uneven carrier injection, uneven gain, and at the same time, the laser gain spectrum becomes wider and the peak gain decreases, resulting in an increase in the laser threshold current and a decrease in slope efficiency;

[0010] 2) The step difference of the laser valence band increases, the hole transport in the quantum well becomes more difficult, the carrier injection is uneven, and the gain is uneven;

[0011] 3) After the laser is lased, the carrier concentration in the multi-quantum well active region is saturated, the bipolar conductivity effect is weakened, and the series resistance of the laser increases, causing the laser voltage to rise. Summary of the invention

[0012] To solve one of the above technical problems, the present invention provides a GaN-based semiconductor laser element.

[0013] The embodiment of the present invention provides a GaN-based semiconductor laser element, comprising a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper confinement layer arranged in sequence from bottom to top, wherein a Bloch-Floquet oscillation layer is arranged between the lower waveguide layer and the active layer, wherein the Bloch-Floquet oscillation layer has a thermal conductivity distribution characteristic and a dielectric constant distribution characteristic, and the thermal conductivity of the Bloch-Floquet oscillation layer has a function y1=M+Ue x +sinx curve distribution, the dielectric constant of the Bloch-Floquet oscillation layer has a function y2=N+Acos(Bx+C) curve distribution, and x is the depth of the Bloch-Floquet oscillation layer toward the active layer.

[0014] Preferably, the Bloch-Floquet oscillator layer also has a refractive index coefficient distribution characteristic, and the refractive index coefficient of the Bloch-Floquet oscillator layer has a curve distribution of function y3=P+Dcos(Ex+F), and N≥P.

[0015] Preferably, the Bloch-Floquet oscillator layer also has a piezoelectric polarization coefficient distribution characteristic, and the piezoelectric polarization coefficient of the Bloch-Floquet oscillator layer has a function y4=Q+Ve x -cosx curve distribution, and M≥Q.

[0016] Preferably, the Bloch-Floquet oscillator layer also has an In / H element ratio distribution characteristic, and the In / H element ratio of the Bloch-Floquet oscillator layer has a curve distribution of function y5=R+Gcos(Hx+I).

[0017] Preferably, the Bloch-Floquet oscillation layer also has an In / O element ratio distribution characteristic, and the In / O element ratio of the Bloch-Floquet oscillation layer has a curve distribution of function y6=S+Jcos(Kx+L).

[0018] Preferably, the Bloch-Floquet oscillation layer also has an In / C element ratio distribution characteristic, and the In / C element ratio of the Bloch-Floquet oscillation layer has a function y7=T+We x +sinx curve distribution, and T≥S≥R.

[0019] Preferably, the Bloch-Floquet oscillator 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.

[0020] Preferably, the active layer is a periodic structure composed of a well layer and a barrier layer, and the number of periods is 3≥m≥1;

[0021] 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 has a thickness of 10 angstroms to 80 angstroms;

[0022] 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 to 120 angstroms.

[0023] Preferably, the lower limiting layer, the lower waveguide layer, the upper waveguide layer and the upper limiting 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.

[0024] Preferably, the substrate comprises sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, sapphire / AlN composite substrate, sapphire / SiN x , Sapphire / SiO2 / SiN x Any one of a composite substrate, a magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

[0025] The beneficial effects of the present invention are as follows: the present invention arranges a Bloch-Floquet oscillation layer between the lower waveguide layer and the active layer of the GaN-based semiconductor laser element, and designs specific thermal conductivity distribution characteristics and dielectric constant distribution characteristics in the Bloch-Floquet oscillation layer, so that the edge and surface of the Bloch-Floquet oscillation layer are topologically protected zero-gap Majorana fermions, a Dirac cone energy band with a spiral structure is generated at the Fermi level, Bloch-Floquet oscillation is induced, and coherent quantum transport is formed, so as to ensure that the quantization of the active layer of the laser element is not affected by the disorder and interaction in the tunnel coupling, and the active The quantum well interface degradation caused by the phase separation segregation of the layer In and thermal degradation improves the quality of the quantum well in the active layer, reduces the non-radiative recombination center, improves the periodic oscillation of the quantum particles in the quantum well, and reduces the threshold current; at the same time, the Bloch-Floquet oscillation layer produces strong interlayer coupling, forming a fractional Floquet tunneling effect, which flattens the energy band near the charge neutrality. Adding a small amount of carriers at half filling can greatly improve the conductivity, improve the transport and injection of electrons and holes in the active layer, reduce the series resistance and voltage of the laser, and improve the peak gain and gain uniformity, thereby improving the optical power and slope efficiency of the laser element. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0027] Figure 1 A schematic structural diagram of a GaN-based semiconductor laser element according to an embodiment of the present invention;

[0028] Figure 2 The SIMS secondary ion mass spectrum of the GaN-based semiconductor laser element according to the embodiment of the present invention;

[0029] Figure 3 This is a locally enlarged SIMS secondary ion mass spectrum of the GaN-based semiconductor laser element described in an embodiment of the present invention.

[0030] Reference numerals:

[0031] 100. substrate, 101. lower confinement layer, 102. lower waveguide layer, 103. active layer, 104. upper waveguide layer, 105. upper confinement layer, 106. Bloch-Floquet oscillation layer. DETAILED DESCRIPTION

[0032] In order to make the technical solutions and advantages in the embodiments of the present application more clearly understood, the exemplary embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0033] like Figures 1 to 3 As shown, this embodiment proposes a GaN-based semiconductor laser element, including 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 in sequence from bottom to top, and a Bloch-Floquet oscillation layer 106 is also arranged in the GaN-based semiconductor laser element.

[0034] Specifically, in this embodiment, the GaN-based semiconductor laser element is provided with 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 from bottom to top. A Bloch-Floquet oscillator layer 106 is also provided in the semiconductor laser element. The Bloch-Floquet oscillator layer 106 is provided between the lower waveguide layer 102 and the active layer 103. In the Bloch-Floquet oscillator layer 106, there are specific thermal conductivity distribution characteristics and dielectric constant distribution characteristics, which are specifically manifested as follows:

[0035] The thermal conductivity of the Bloch-Floquet oscillating layer 106 has the function y1=M+Ue x +sinx curve distribution;

[0036] The dielectric constant of the Bloch-Floquet oscillator layer 106 has a curve distribution of the function y2=N+Acos(Bx+C);

[0037] Wherein, x is the depth of the Bloch-Floquet oscillator layer 106 toward the active layer 103 .

[0038] In this embodiment, a Bloch-Floquet oscillator layer 106 is arranged between the lower waveguide layer 102 and the active layer 103 of the GaN-based semiconductor laser element, and specific thermal conductivity distribution characteristics and dielectric constant distribution characteristics are designed in the Bloch-Floquet oscillator layer 106, so that the edge and surface of the Bloch-Floquet oscillator layer 106 are topologically protected zero-gap Majorana fermions, and a Dirac cone energy band with a spiral structure is generated at the Fermi level, thereby inducing Bloch-Floquet oscillations and forming coherent quantum transport, thereby ensuring that the quantization of the active layer 103 of the laser element is not affected by the disorder and interaction in the tunnel coupling, and suppressing the active layer 1 03In phase separation segregation and thermal degradation cause quantum well interface degradation, improve the quality of the active layer 103 quantum well, reduce non-radiative recombination centers, improve the periodic oscillation of quantum particles in the quantum well, and reduce the threshold current; at the same time, the Bloch-Floquet oscillation layer 106 produces strong interlayer coupling, forming a fractional Floquet tunneling effect, which flattens the energy band near charge neutrality. Adding a small amount of carriers at half filling can greatly improve the conductivity, improve the transport and injection of electrons and holes in the active layer 103, reduce the laser series resistance and voltage, and improve the peak gain and gain uniformity, thereby improving the optical power and slope efficiency of the laser element.

[0039] In some optional embodiments, the Bloch-Floquet oscillator layer 106 also has a refractive index coefficient distribution characteristic. Specifically, the refractive index coefficient of the Bloch-Floquet oscillator layer 106 has a function y3=P+Dcos(Ex+F) curve distribution, and N≥P.

[0040] In some optional embodiments, the Bloch-Floquet oscillator layer 106 also has a piezoelectric polarization coefficient distribution characteristic. Specifically, the piezoelectric polarization coefficient of the Bloch-Floquet oscillator layer 106 has a function y4=Q+Ve x -cosx curve distribution, and M≥Q.

[0041] In some optional embodiments, Figure 2 and Figure 3 As shown, the Bloch-Floquet oscillator layer 106 also has an In / H element ratio distribution characteristic. Specifically, the In / H element ratio of the Bloch-Floquet oscillator layer 106 has a function y5=R+Gcos(Hx+I) curve distribution.

[0042] In some optional embodiments, the Bloch-Floquet oscillator layer 106 also has an In / O element ratio distribution characteristic. Specifically, the In / O element ratio of the Bloch-Floquet oscillator layer 106 has a function y6=S+Jcos(Kx+L) curve distribution.

[0043] In some optional embodiments, the Bloch-Floquet oscillator layer 106 also has an In / C element ratio distribution characteristic. Specifically, the In / C element ratio of the Bloch-Floquet oscillator layer 106 has a function y7=T+We x +sinx curve distribution, and T≥S≥R.

[0044] In some optional embodiments, the Bloch-Floquet oscillator layer 106 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.

[0045] In some optional embodiments, the active layer 103 is a periodic structure composed of a well layer and a barrier layer, and the number of periods is 3≥m≥1.

[0046] 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 to 80 angstroms.

[0047] 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 to 120 angstroms.

[0048] 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.

[0049] In some optional embodiments, the substrate 100 includes sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, sapphire / AlN composite substrate, sapphire / SiN x , Sapphire / SiO2 / SiN x Any one of a composite substrate, a magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

[0050] The following table is a parameter comparison between a conventional semiconductor laser element and the GaN-based semiconductor laser element proposed in this embodiment, including slope efficiency, threshold current density, optical power, voltage, and series resistance to show the difference between the conventional semiconductor laser element and the GaN-based semiconductor laser element proposed in this embodiment:

[0051]

[0052] It can be seen that the GaN-based semiconductor laser element proposed in this embodiment improves the slope efficiency and optical power, reduces the threshold current density, voltage and series resistance compared with traditional semiconductor laser elements, and has obvious advantages over traditional semiconductor laser elements.

[0053] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A GaN-based semiconductor laser element, comprising a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper confinement layer arranged in sequence from bottom to top, characterized in that: A Bloch-Floquet oscillation layer is arranged between the lower waveguide layer and the active layer. The Bloch-Floquet oscillation layer has a thermal conductivity distribution characteristic and a dielectric constant distribution characteristic. The thermal conductivity of the Bloch-Floquet oscillation layer has a function y1=M+Ue x +sinx curve distribution, the dielectric constant of the Bloch-Floquet oscillation layer has a function y2=N+Acos(Bx+C) curve distribution, and x is the depth of the Bloch-Floquet oscillation layer toward the active layer.

2. The GaN-based semiconductor laser element according to claim 1, characterized in that: The Bloch-Floquet oscillator layer also has a refractive index coefficient distribution characteristic. The refractive index coefficient of the Bloch-Floquet oscillator layer has a curve distribution of function y3=P+Dcos(Ex+F), and N≥P.

3. The GaN-based semiconductor laser element according to claim 1, characterized in that: The Bloch-Floquet oscillator layer also has a piezoelectric polarization coefficient distribution characteristic. The piezoelectric polarization coefficient of the Bloch-Floquet oscillator layer has a function y4=Q+Ve x -cosx curve distribution, and M≥Q.

4. The GaN-based semiconductor laser element according to claim 1, characterized in that: The Bloch-Floquet oscillation layer also has an In / H element ratio distribution characteristic. The In / H element ratio of the Bloch-Floquet oscillation layer has a function y5=R+Gcos(Hx+I) curve distribution.

5. The GaN-based semiconductor laser element according to claim 4, characterized in that: The Bloch-Floquet oscillation layer also has an In / O element ratio distribution characteristic. The In / O element ratio of the Bloch-Floquet oscillation layer has a function y6=S+Jcos(Kx+L) curve distribution.

6. The GaN-based semiconductor laser element according to claim 5, characterized in that: The Bloch-Floquet oscillation layer also has an In / C element ratio distribution characteristic. The In / C element ratio of the Bloch-Floquet oscillation layer has a function y7=T+We x +sinx curve distribution, and T≥S≥R.

7. The GaN-based semiconductor laser element according to claim 1, characterized in that: The Bloch-Floquet oscillator 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.

8. The GaN-based semiconductor laser element according to claim 1, characterized in that: The active layer is a periodic structure composed of a well layer and a barrier layer, and the number of periods 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 has a thickness of 10 angstroms to 80 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, and BN, with a thickness of 10 to 120 angstroms.

9. The GaN-based semiconductor laser element according to claim 1, characterized in that: The lower limiting layer, lower waveguide layer, upper waveguide layer and upper limiting 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.

10. The GaN-based semiconductor laser element according to claim 1, characterized in that: The substrate includes sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, sapphire / AlN composite substrate, sapphire / SiN x , Sapphire / SiO2 / SiN x Any one of a composite substrate, a magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

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