Group III nitride semiconductor laser

Abstract

The III-nitride semiconductor laser comprises a substrate, a lower limiting layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer and an upper limiting layer which are sequentially arranged from bottom to top. A non-reciprocal topology laser oscillation layer is arranged between an upper limiting layer and an electron blocking layer of the semiconductor laser. Specific conduction band effective state density distribution, dielectric constant distribution and peak rate electric field distribution of the nonreciprocal topology laser oscillation layer, a photonic structure formed by interfaces of the upper limiting layer, the upper waveguide layer and / or the lower limiting layer and the lower waveguide layer, and a one-way photonic band gap edge state between specific topology invariants; the magneto-optical effect is regulated and controlled through a non-diagonal dielectric tensor to enhance nonreciprocity, circularly polarized light propagating in the chiral displacement direction obtains different phases and attenuation, stimulated radiation laser of an active layer is regulated and controlled to be coupled to a specific waveguide to be output, internal optical loss is restrained, the mode gain of a laser element is improved, and the optical power and slope efficiency of the laser element are improved.

Description

Technical Field

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

[0002] Lasers are widely used in laser displays, laser televisions, laser projectors, communications, medical treatment, weaponry, guidance, rangefinders, spectral analysis, cutting, precision welding, high-density optical storage, and other fields. There are many different types of lasers, classified in various ways, including solid-state, gas, liquid, semiconductor, and dye lasers. Compared with other types of lasers, all-solid-state semiconductor lasers offer advantages such as small size, high efficiency, light weight, excellent stability, long life, simple and compact structure, and miniaturization.

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

[0004] 1) Laser is generated by stimulated radiation of carriers, with a small spectral half-width and high brightness. The output power of a single laser can be in the W level, while nitride semiconductor light-emitting diodes emit spontaneous radiation, 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. The energy of the induced photon should be equal to the difference in the energy level of the electron transition, and the photon and the induced photon are completely coherent light;

[0007] 4) Different principles: Light-emitting diodes generate radiative recombination light when electrons and holes jump to quantum wells or pn junctions under the action of external voltage, while lasers require that lasing conditions be met before lasing. The carrier inversion distribution in the active region must be met, 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 optical waveguide has high absorption loss. Intrinsic carbon impurities in p-type semiconductors will compensate for acceptors and destroy the p-type. The ionization rate of p-type doping is low, and a large amount of unionized Mg acceptor impurities will lead to increased internal optical losses. In addition, the refractive index dispersion of the laser and the limiting factor decrease with increasing wavelength, resulting in a decrease in the mode gain of the laser.

[0010] 2) Increasing the thickness of the lower confinement layer can reduce the refractive index of the confinement layer, but this will limit the composition control range and easily cause problems such as cracking, bending, and quality degradation. At the same time, the light field mode leaks into the substrate to form standing waves, resulting in low substrate mode suppression efficiency and poor far-field image FFP quality.

[0011] 3) The Mg acceptor activation energy of p-type semiconductors is large and the ionization efficiency is low. The hole concentration is much lower than the electron concentration, the hole mobility is much smaller than the electron mobility, and the quantum well polarization electric field increases the hole injection barrier, 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, making it more difficult for holes to be transported in the quantum well, uneven carrier injection, and uneven gain. 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. Summary of the Invention

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

[0013] An embodiment of the present invention provides a III-nitride semiconductor laser, comprising 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, arranged in sequence from bottom to top. A non-reciprocal topological laser oscillation layer is provided between the upper confinement layer and the electron blocking layer. The non-reciprocal topological laser oscillation layer has conduction band effective state density distribution characteristics, dielectric constant distribution characteristics, and peak rate electric field distribution characteristics.

[0014] The conduction band effective state density of the non-reciprocal topological laser oscillation layer has a function y1=A+B*log a x curve distribution, 0<a<1;

[0015] The dielectric constant of the non-reciprocal topological laser oscillation layer has the function y2=C+D*(b x +1) / (b x -1) curve distribution, 0<b<1;

[0016] The peak rate electric field of the non-reciprocal topological laser oscillation layer has a function y3=E+F*(e x +e -x ) / (e x -e -x ) first quadrant curve distribution;

[0017] Where x is the depth from the non-reciprocal topological laser oscillation layer to the upper confinement layer.

[0018] Preferably, the non-reciprocal topological laser oscillation layer also has a covalent bond energy distribution characteristic, and the covalent bond energy of the non-reciprocal topological laser oscillation layer has a function y4=G+H*(e x +e -x ) / (e x -e -x )First quadrant curve distribution.

[0019] Preferably, the non-reciprocal topological laser oscillation layer also has a heavy hole effective mass distribution characteristic, and the heavy hole effective mass of the non-reciprocal topological laser oscillation layer has a function y5=I+J*(e x +e -x ) / (e x -e -x )First quadrant curve distribution.

[0020] Preferably, the non-reciprocal topological laser oscillation layer further has a Philips ionization distribution characteristic, and the Philips ionization of the non-reciprocal topological laser oscillation layer has a function y6=K+L*log c ((m+x) / (mx)) The fourth quadrant curve distribution, 0<c<1, m>0.

[0021] Preferably, the non-reciprocal topological laser oscillation layer further has an In / C element ratio distribution characteristic, and the In / C element ratio of the non-reciprocal topological laser oscillation layer has a function y7=M+N*(d x +1) / (d x -1) curve distribution, 0<d<1.

[0022] Preferably, the non-reciprocal topological laser oscillation layer further has an In / O element ratio distribution characteristic, and the In / O element ratio of the non-reciprocal topological laser oscillation layer has a function y8=P+Q*log f ((n+x) / (nx)) The fourth quadrant curve distribution, 0<f<1, n>0.

[0023] Preferably, the non-reciprocal topological laser oscillation 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.

[0024] Preferably, the active layer is a periodic structure consisting of a well layer and a barrier layer, with the number of periods being 1 to 3, the well layer being any one or any combination of InGaN, InN, AlInN, and GaN, with a thickness of 10 angstroms to 10 angstroms, and the barrier layer being any one or any combination of GaN, AlGaN, AlInGaN, AlN, and AlInN, with a thickness of 10 angstroms to 120 angstroms.

[0025] Preferably, the lower confinement layer, the lower waveguide layer, the upper waveguide layer, the electron blocking layer and the 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.

[0026] Preferably, 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.

[0027] The beneficial effects of the present invention are as follows: The present invention provides a non-reciprocal topological laser oscillation layer between the upper confinement layer and the electron blocking layer of the semiconductor laser, and defines the conduction band effective state density distribution characteristics, dielectric constant distribution characteristics and peak rate electric field distribution characteristics of the non-reciprocal topological laser oscillation layer, so that the specific conduction band effective state density distribution, dielectric constant distribution and peak rate electric field distribution of the non-reciprocal topological laser oscillation layer and the photonic structure formed at the interface of the upper confinement layer, the upper waveguide layer and / or the lower confinement layer, the lower waveguide layer, and the unidirectional photonic band gap edge state between the specific topological invariants, enhance the non-reciprocity by regulating the magneto-optical effect through the non-diagonal dielectric tensor, obtain different phases and attenuations of the circularly polarized light propagating along the chiral displacement direction, regulate the stimulated emission laser coupling of the active layer to the specific waveguide output, suppress internal optical loss, improve the mode gain of the laser element, and improve the optical power and slope efficiency of the laser element. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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:

[0029] Figure 1 Schematic diagram of the structure of a III-nitride semiconductor laser according to an embodiment of the present invention;

[0030] Figure 2 This is a SIMS secondary ion mass spectrum of the III-nitride semiconductor laser according to an embodiment of the present invention.

[0031] Reference numerals:

[0032] 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. Non-reciprocal topological laser oscillation layer. DETAILED DESCRIPTION

[0033] In order to make the technical solutions and advantages of the embodiments of the present application more clearly understood, the exemplary embodiments of the present application are further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, and are not an exhaustive list of all the embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other unless they conflict.

[0034] like Figure 1 and Figure 2 As shown, this embodiment provides a III-nitride semiconductor laser, comprising, arranged in order 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 non-reciprocal topological laser oscillation layer 107 is also provided in the III-nitride semiconductor laser.

[0035] Specifically, in this embodiment, the III-nitride semiconductor laser 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, an electron blocking layer 105, and an upper confinement layer 106 in order from bottom to top. The non-reciprocal topological laser oscillation layer 107 is located between the upper confinement layer 106 and the electron blocking layer 105. The non-reciprocal topological laser oscillation layer 107 has some specific physical property distributions, including but not limited to the conduction band effective state density distribution characteristics, the dielectric constant distribution characteristics, and the peak rate electric field distribution characteristics. Among them, the specific manifestations of the conduction band effective state density distribution characteristics, the dielectric constant distribution characteristics, and the peak rate electric field distribution characteristics in the non-reciprocal topological laser oscillation layer 107 are as follows:

[0036] Conduction band effective state density distribution:

[0037] The conduction band effective state density of the non-reciprocal topological laser oscillation layer 107 has the function y1=A+B*log a x curve distribution, 0<a<1;

[0038] Dielectric constant distribution:

[0039] The dielectric constant of the non-reciprocal topological laser oscillation layer 107 has the function y2=C+D*(b x +1) / (b x -1) curve distribution, 0<b<1;

[0040] Peak rate electric field distribution:

[0041] The peak rate electric field of the non-reciprocal topological laser oscillation layer 107 has a function y3=E+F*(e x +e -x ) / (e x -e -x ) first quadrant curve distribution;

[0042] Here, x is the depth from the non-reciprocal topological laser oscillation layer 107 to the upper confinement layer 106 .

[0043] In this embodiment, a non-reciprocal topological laser oscillation layer 107 is provided between the upper confinement layer 106 and the electron blocking layer 105 of the semiconductor laser, and the conduction band effective state density distribution characteristics, dielectric constant distribution characteristics, and peak rate electric field distribution characteristics of the non-reciprocal topological laser oscillation layer 107 are defined. The photonic structure formed at the interface between the specific conduction band effective state density distribution, dielectric constant distribution, and peak rate electric field distribution of the non-reciprocal topological laser oscillation layer 107 and the upper confinement layer 106, the upper waveguide layer 104, and / or the lower confinement layer 101, and the lower waveguide layer 102, and the unidirectional photonic band gap edge state between the specific topological invariants, is enhanced by regulating the magneto-optical effect through the non-diagonal dielectric tensor, and the circularly polarized light propagating along the chiral displacement direction obtains different phases and attenuations, and the stimulated emission laser of the active layer 103 is regulated to couple to a specific waveguide output, thereby suppressing internal optical losses, improving the mode gain of the laser element, and improving the optical power and slope efficiency of the laser element.

[0044] In some optional embodiments, the non-reciprocal topological laser oscillation layer 107 further has a covalent bond energy distribution characteristic, specifically: the covalent bond energy of the non-reciprocal topological laser oscillation layer 107 has a function y4=G+H*(e x +e -x ) / (e x -e -x )First quadrant curve distribution.

[0045] In some optional embodiments, the non-reciprocal topological laser oscillation layer 107 further has a heavy hole effective mass distribution characteristic, specifically: the heavy hole effective mass of the non-reciprocal topological laser oscillation layer 107 has a function y5=I+J*(e x +e -x ) / (e x -e -x )First quadrant curve distribution.

[0046] In some optional embodiments, the non-reciprocal topological laser oscillation layer 107 further has a Philips ionization distribution characteristic, specifically: the Philips ionization of the non-reciprocal topological laser oscillation layer 107 has a function y6=K+L*log c ((m+x) / (mx)) The fourth quadrant curve distribution, 0<c<1, m>0.

[0047] In some optional embodiments, the non-reciprocal topological laser oscillation layer 107 further has an In / C element ratio distribution characteristic, specifically: the In / C element ratio of the non-reciprocal topological laser oscillation layer 107 has a function y7=M+N*(d x +1) / (d x -1) curve distribution, 0<d<1.

[0048] In some optional embodiments, the non-reciprocal topological laser oscillation layer 107 further has an In / O element ratio distribution characteristic, specifically: the In / O element ratio of the non-reciprocal topological laser oscillation layer 107 has a function y8=P+Q*log f ((n+x) / (nx)) The fourth quadrant curve distribution, 0<f<1, n>0.

[0049] In this embodiment, the specific covalent bond energy distribution, specific heavy hole effective mass distribution, specific Philips ionization degree distribution and specific element ratio distribution (including In / C element ratio distribution and In / O element ratio distribution) of the non-reciprocal topological laser oscillation layer 107 regulate the laser coupling intensity, enhance the polarization intensity through exciton emission, induce hole ionization and hybridization, form a polariton pumped laser effect, enhance the laser pumping efficiency, suppress light field mode leakage, enhance the far-field image FFP quality, enhance the beam quality factor, thereby enhancing the radiation recombination efficiency of the laser element active layer 103, reducing the excitation threshold of the laser element, and further enhancing the optical power and slope efficiency of the laser element.

[0050] In some optional embodiments, the non-reciprocal topological laser oscillation layer 107 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.

[0051] In some optional embodiments, the active layer 103 is a periodic structure consisting of a well layer and a barrier layer, with the number of periods being 1 to 3. The well layer is any one or any combination of InGaN, InN, AlInN, and GaN, with a thickness of 10 angstroms to 10 angstroms. The barrier layer is any one or any combination of GaN, AlGaN, AlInGaN, AlN, and AlInN, with a thickness of 10 angstroms to 120 angstroms.

[0052] In some optional embodiments, 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, and BN.

[0053] 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 Composite substrate, any one of magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrates.

[0054] The following table compares the parameters of a conventional semiconductor laser device and the III-nitride semiconductor laser proposed in this embodiment, including beam quality factor, slope efficiency, threshold current density, optical power, and internal optical loss, showing the differences between the conventional semiconductor laser device and the III-nitride semiconductor laser proposed in this embodiment:

[0055]

[0056] It can be seen that the III-nitride semiconductor laser proposed in this embodiment has improved beam quality factor, slope efficiency and optical power, reduced threshold current density and internal optical loss compared with traditional semiconductor laser elements, and has obvious advantages over traditional semiconductor laser elements.

[0057] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A III-nitride semiconductor laser comprising, arranged in order 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: A non-reciprocal topological laser oscillation layer is provided between the upper confinement layer and the electron blocking layer, wherein the non-reciprocal topological laser oscillation layer has conduction band effective state density distribution characteristics, dielectric constant distribution characteristics and peak rate electric field distribution characteristics; The conduction band effective state density of the non-reciprocal topological laser oscillation layer has a function y1=A+B*log a x curve distribution, 0<a<1; The dielectric constant of the non-reciprocal topological laser oscillation layer has the function y2=C+D*(b x +1) / (b x -1) curve distribution, 0<b<1; The peak rate electric field of the non-reciprocal topological laser oscillation layer has a function y3=E+F*(e x +e -x ) / (e x -e -x ) first quadrant curve distribution; Where x is the depth from the non-reciprocal topological laser oscillation layer to the upper confinement layer.

2. The III-nitride semiconductor laser according to claim 1, wherein The non-reciprocal topological laser oscillation layer also has a covalent bond energy distribution characteristic. The covalent bond energy of the non-reciprocal topological laser oscillation layer has a function y4=G+H*(e x +e -x ) / (e x -e -x )First quadrant curve distribution.

3. The III-nitride semiconductor laser according to claim 1, wherein The non-reciprocal topological laser oscillation layer also has a heavy hole effective mass distribution characteristic. The heavy hole effective mass of the non-reciprocal topological laser oscillation layer has a function y5=I+J*(e x +e -x ) / (e x -e -x )First quadrant curve distribution.

4. The III-nitride semiconductor laser according to claim 1, wherein The non-reciprocal topological laser oscillation layer also has a Philips ionization distribution characteristic. The Philips ionization of the non-reciprocal topological laser oscillation layer has a function y6=K+L*log c ((m+x) / (mx)) The fourth quadrant curve distribution, 0<c<1, m>0.

5. The III-nitride semiconductor laser according to claim 1, wherein The non-reciprocal topological laser oscillation layer also has an In / C element ratio distribution characteristic. The In / C element ratio of the non-reciprocal topological laser oscillation layer has a function y7=M+N*(d x +1) / (d x -1) curve distribution, 0<d<1.

6. The III-nitride semiconductor laser according to claim 1, wherein The non-reciprocal topological laser oscillation layer also has an In / O element ratio distribution characteristic. The In / O element ratio of the non-reciprocal topological laser oscillation layer has a function y8=P+Q*log f ((n+x) / (nx)) The fourth quadrant curve distribution, 0<f<1, n>0.

7. The III-nitride semiconductor laser according to claim 1, wherein The non-reciprocal topological laser oscillation 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 III-nitride semiconductor laser according to claim 1, wherein The active layer is a periodic structure consisting of a well layer and a barrier layer, with the number of periods being 1 to 3. The well layer is any one or any combination of InGaN, InN, AlInN, and GaN, with a thickness of 10 angstroms to 10 angstroms. The barrier layer is any one or any combination of GaN, AlGaN, AlInGaN, AlN, and AlInN, with a thickness of 10 angstroms to 120 angstroms.

9. The III-nitride semiconductor laser according to claim 1, wherein 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, and BN.

10. The III-nitride semiconductor laser according to claim 1, wherein 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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