A gallium nitride-based semiconductor blue laser

Abstract

The application provides a gallium nitride-based semiconductor blue laser, which comprises, from bottom to top, a substrate, a lower limiting layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper limiting layer, wherein a topological interface state layer is arranged between the upper waveguide layer and the upper limiting layer, and the topological interface state layer has breakdown field strength distribution characteristics and electron affinity energy distribution characteristics. Through the specific breakdown field strength distribution and electron affinity energy distribution of the topological interface state layer, a new body boundary energy band is formed, a strong spin center is formed at the interface, the coupling between adjacent interface states and the spin-splitting asymmetry of the electron band structure are enhanced, the spin-orbit torque effect is enhanced, the piezoelectric polarization and the thermal stress mismatch of the laser element are relieved, the valence band step is reduced, the uniformity of the valence band step is improved, the uniformity of the carrier injection into the active layer is improved, and the gain uniformity is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor optoelectronic devices, in particular to a gallium nitride-based semiconductor blue laser. BACKGROUND

[0002] Laser is widely used in laser display, laser television, laser projector, communication, medical treatment, weapon, guidance, ranging, spectrum analysis, cutting, precision welding, high-density optical storage and other fields. There are many types of lasers, and the classification methods are also various. The main types of lasers include solid, gas, liquid, semiconductor and dye 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 service life, simple and compact structure, and miniaturization.

[0003] There are great differences between laser and nitride semiconductor light-emitting diode:

[0004] 1) Laser is generated by stimulated radiation of carriers, with small spectral half-width and high brightness. The output power of a single laser can reach W level, while the output power of a single light-emitting diode is in mW level.

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

[0006] 3) Light-emitting diode is spontaneously transitioned and radiated without external action, and the incoherent light is transitioned from high energy level to low energy level. Laser is stimulated transition radiation, and the energy of induced photon should be equal to the difference between the energy levels of electron transition. The generated photon and induced photon are homophase coherent light.

[0007] 4) Different principles: Light-emitting diode is under the action of external voltage, and electron-hole is transitioned to quantum well or p-n junction to produce radiation recombination. Laser needs to meet the lasing conditions, and must meet the carrier inversion distribution in the active region. The stimulated radiation light oscillates back and forth in the resonant cavity, propagates in the gain medium to amplify the light, and finally outputs laser when the gain is greater than the loss and the threshold condition is met.

[0008] The nitride semiconductor laser has the following problems:

[0009] (1) Active layer lattice mismatch and large strain induced strong piezoelectric polarization effect, resulting in strong QCSE quantum confinement Stark effect, which limits the improvement of the electric excitation gain of the laser; the band gap difference of the laser increases, the hole transport in the quantum well is more difficult, the carrier injection is uneven, and the gain is uneven; after the laser is excited, the carrier concentration of the multi-quantum well active region is saturated, the bipolar conduction effect is weakened, the series resistance of the laser increases, and the voltage of the laser rises;

[0010] (2) Thermal loss: the Stokes shift loss formed by the photon energy difference between the pump light and the oscillation light is converted into heat, and the energy loss converted into heat due to the coupling rate of the pump level to the laser upper level not being 1, both of which together produce a large amount of waste heat, making the temperature distribution of the laser uneven, causing thermal expansion and thermal stress distribution to be uneven, producing stress birefringence effect, changing the polarization state of the incident light, and making the laser beam depolarization and distortion. SUMMARY

[0011] To solve one of the above technical problems, the application provides a gallium nitride-based semiconductor blue laser.

[0012] The gallium nitride-based semiconductor blue laser provided by the embodiment of the application comprises, 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, a topological interface state layer is arranged between the upper waveguide layer and the upper confinement layer, the topological interface state layer has breakdown field strength distribution characteristics and electron affinity energy distribution characteristics, the breakdown field strength of the topological interface state layer has a function y1=A+B*arccoshx curve distribution, and the electron affinity energy of the topological interface state layer has a function y2=C+E*e x / x first quadrant curve distribution, and x is the depth of the topological interface state layer in the direction of the upper confinement layer.

[0013] Preferably, the topological interface state layer also has valence band effective state density distribution characteristics, and the valence band effective state density of the topological interface state layer has a function y3=F+G*x 2 +H*sinx curve distribution.

[0014] Preferably, the topological interface state layer also has elastic coefficient distribution characteristics, and the elastic coefficient of the topological interface state layer has a function y4=J+K*ln(x+1)-L*e x curve distribution.

[0015] Preferably, the topological interface state layer also has In / Si element ratio distribution characteristics, and the In / Si element ratio of the topological interface state layer has a function y5=M+N*x-(a / x) first four-quadrant curve distribution, wherein 0

[0016] Preferably, the topological interface state 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.

[0017] Preferably, the active layer is a periodic structure composed of well layers and barrier layers, and the number of periods is 3≥m≥1.

[0018] Preferably, the well layer of the active layer is 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, and the thickness is 10 angstroms to 100 angstroms.

[0019] Preferably, the barrier layer of the active layer is 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, and the thickness is 10 angstroms to 200 angstroms.

[0020] Preferably, the lower confining layer, the lower waveguide layer, the upper waveguide layer, 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.

[0021] Preferably, the substrate comprises any one of sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2composite substrate, sapphire / AlN composite substrate, sapphire / SiN x x composite substrate, magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2and LiGaO2composite substrate.

[0022] The beneficial effects of the present application are as follows: the present application is provided with a topological interface state layer between the upper waveguide layer and the upper confining layer of the gallium nitride-based semiconductor blue laser, and the breakdown field strength distribution characteristics and the electron affinity energy distribution characteristics of the topological interface state layer are limited, the specific breakdown field strength distribution and the electron affinity energy distribution of the topological interface state layer cooperate together to form a new body boundary energy band, a strong spin center is formed at the interface, the coupling between adjacent interface states and the spin splitting asymmetry of the electron energy band structure are enhanced, the spin-orbit torque effect is enhanced, the piezoelectric polarization and the thermal stress mismatch of the laser element are relieved, the valence band step is reduced, the uniformity of the valence band step is improved, the uniformity of the carrier injection active layer is improved, and the gain uniformity is improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application. The illustrative embodiments of the present application and their descriptions serve to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0024] Figure 1 The structure schematic diagram of the gallium nitride-based semiconductor blue laser described in the embodiments of the present application;

[0025] Figure 2 The SIMS secondary ion mass spectrum of the gallium nitride-based semiconductor blue laser described in the embodiments of the present application.

[0026] Reference signs:

[0027] ​100, substrate, 101, lower confinement layer, 102, lower waveguide layer, 103, active layer, 104, upper waveguide layer, 105, upper confinement layer, 106, topological interface state layer. DETAILED DESCRIPTION

[0028] In order to make the technical solutions and advantages in the embodiments of the present application clearer, the exemplary embodiments of the present application are further described in detail below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, not 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.

[0029] As shown in Figure 1 and Figure 2 , the present embodiment proposes a gallium nitride-based semiconductor blue laser, which comprises, 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. The gallium nitride-based semiconductor blue laser further comprises a topological interface state layer 106.

[0030] Specifically, in the present embodiment, the gallium nitride-based semiconductor blue laser comprises, 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. The topological interface state layer 106 is arranged between the upper waveguide layer 104 and the upper confinement layer 105. The topological interface state layer 106 has specific breakdown field strength distribution characteristics and electron affinity energy distribution characteristics, which are specifically as follows:

[0031] (1) Breakdown field strength distribution of the topological interface state layer 106

[0032] The breakdown field strength of the topological interface state layer 106 has a function y1=A+B*arccoshx curve distribution;

[0033] (2) Electron affinity energy distribution of the topological interface state layer 106

[0034] The electron affinity energy of the topological interface state layer 106 has a function y2=C+E*e x / x first quadrant curve distribution;

[0035] Wherein, x is the depth of the topological interface state layer 106 in the direction of the upper confinement layer 105.

[0036] The embodiment sets the topological interface state layer 106 between the upper waveguide layer 104 and the upper confinement layer 105 of the gallium nitride-based semiconductor blue laser, and limits the breakdown field strength distribution characteristics and the electron affinity energy distribution characteristics of the topological interface state layer 106. The specific breakdown field strength distribution and the electron affinity energy distribution of the topological interface state layer 106 cooperate to form a new body boundary energy band, form a strong spin center at the interface, enhance the coupling between adjacent interface states and the spin splitting asymmetry of the electron energy band structure, enhance the spin-orbit torque effect, relieve the piezoelectric polarization and thermal stress mismatch of the laser element, reduce the valence band gap, improve the uniformity of the valence band gap, improve the uniformity of the carrier injection active layer 103, and improve the gain uniformity.

[0037] In some optional embodiments, the topological interface state layer 106 also has valence band effective state density distribution characteristics, specifically: the valence band effective state density of the topological interface state layer 106 has a function y3=F+G*x 2 +H*sinx curve distribution.

[0038] In some optional embodiments, the topological interface state layer 106 also has elastic coefficient distribution characteristics, specifically: the elastic coefficient of the topological interface state layer 106 has a function y4=J+K*ln(x+1)-L*e x curve distribution.

[0039] In some optional embodiments, the topological interface state layer 106 also has In / Si element ratio distribution characteristics, specifically: the In / Si element ratio of the topological interface state layer 106 has a function y5=M+N*x-(a / x) first fourth quadrant curve distribution, where 0

[0040] The embodiment can control the topological interface state by limiting the valence band effective state density distribution characteristics, the elastic coefficient distribution characteristics, and the In / Si element ratio distribution characteristics of the topological interface state layer 106, so that the spin of the topological interface state electron is locked in the momentum, the non-trivial Berry phase is generated by the time-reversal-protected self-intersection path of the active layer 103 in the quantum diffusion region, the phonon anharmonicity, phonon topological state, and phonon relaxation time are enhanced to improve the phonon transmission and lattice thermal conductivity, the coupling rate of the pump level to the laser upper level is improved, the piezothermally stressed mismatch is further reduced, the stress birefringence phenomenon is suppressed, and the depolarization and distortion of the laser beam are improved.

[0041] In some alternative embodiments, the topological interface state 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, BN.

[0042] In some alternative embodiments, the active layer 103 is a periodic structure composed of well layers and barrier layers, and the number of periods is 3≥m≥1.

[0043] Specifically, the well layer of the active layer 103 is 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, and the thickness is 10 angstroms to 100 angstroms.

[0044] The barrier layer of the active layer 103 is 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, and the thickness is 10 angstroms to 200 angstroms.

[0045] In some alternative embodiments, the lower cladding layer 101, the lower waveguide layer 102, the upper waveguide layer 104, the upper cladding layer 105 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.

[0046] In some alternative embodiments, the substrate 100 comprises any one of sapphire, silicon, Ge, SiC, AlN, GaN, GaAs, InP, InAs, GaSb, sapphire / SiO2 composite substrate, sapphire / AlN composite substrate, sapphire / SiN x x composite substrate, MgAl2O4, MgO, ZnO, ZrB2, LiAlO2and LiGaO2composite substrate.

[0047] Obviously, various modifications and changes can be made to the present application by those skilled in the art without departing from the spirit and scope of the application. Accordingly, it is intended that all such modifications and changes be included in the present application as long as they fall within the scope of the claims and their equivalents.​

Claims

1. A gallium nitride-based semiconductor blue laser, 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 order from bottom to top, characterized in that: A topological interface state layer is provided between the upper waveguide layer and the upper confinement layer. The topological interface state layer has a breakdown field strength distribution characteristic and an electron affinity energy distribution characteristic. The breakdown field strength of the topological interface state layer has a function y1=A+B*arccoshx curve distribution, and the electron affinity of the topological interface state layer has a function y2=C+E*e x / xThe first quadrant curve distribution, x is the depth of the topological interface state layer toward the upper limiting layer; The topological interface state layer also has a valence band effective state density distribution characteristic. The valence band effective state density of the topological interface state layer has a function y3=F+G*x 2 +H*sinx curve distribution; The topological interface state layer also has an elastic coefficient distribution characteristic. The elastic coefficient of the topological interface state layer has a function y4=J+K*ln(x+1)-L*e x Curve distribution; The topological interface state layer also has an In / Si element ratio distribution characteristic. The In / Si element ratio of the topological interface state layer has a first four-quadrant curve distribution of the function y5=M+N*x-(a / x), where a is a coefficient and 0<a<1.

2. The gallium nitride-based semiconductor blue laser according to claim 1, characterized in that: The topological interface state 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.

3. The gallium nitride-based semiconductor blue laser according to claim 1, characterized in that: The active layer is a periodic structure composed of a well layer and a barrier layer, and the number of periods is 3≥m≥1.

4. The gallium nitride-based semiconductor blue laser according to claim 3, characterized in that: The well layer of the active 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 100 angstroms.

5. The gallium nitride-based semiconductor blue laser according to claim 3, characterized in that: The barrier layer of the active 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 200 angstroms.

6. The gallium nitride-based semiconductor blue laser according to claim 1, characterized in that: 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.

7. The gallium nitride-based semiconductor blue laser 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 Composite substrate, any one of magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrates.

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