Gallium nitride-based semiconductor purple light laser with low fast axis divergence angle lower waveguide layer

Abstract

The invention discloses a gallium nitride-based semiconductor purple light laser with a low fast axis divergence angle lower waveguide layer, which sequentially comprises a substrate, a lower coating layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper coating layer from bottom to top, and is characterized in that the lower waveguide layer is the low fast axis divergence angle lower waveguide layer; the low fast axis divergence angle lower waveguide layer is any one or any combination of InGaN, GaN, InN and AlInGaN; and the peak rate electric field distribution of the waveguide layer under the low fast axis divergence angle has broken line type distribution. The thickness and refractive index change curve of the lower waveguide layer is modulated, so that the light beam is close to the Gaussian beam, the fast axis divergence angle and the cavity surface power density are reduced, the cavity surface load and the substrate mode leakage are reduced, and the optical power, coherence and far-field FFP image quality of the laser are improved.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor optoelectronic devices, and in particular to a gallium nitride-based semiconductor violet laser with a waveguide layer having a low fast-axis divergence angle. 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 significant differences between lasers and nitride semiconductor light-emitting diodes. 1) Lasers are generated by stimulated radiation from carriers, with a small half-width spectrum 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. 2) The current density of the laser is as high as KA / cm 2 , 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; 3) Light-emitting diodes spontaneously radiate incoherent light from high energy levels to low energy levels without external effects, while lasers radiate stimulated transitions. The energy of induced photons should be equal to the difference in energy levels of electron transitions, generating photons and induced photons that are completely coherent light; 4) Different principles: light-emitting diodes produce radiation recombination and luminescence under the action of external voltage when electron holes transition to quantum wells or pn junctions, while lasers require lasing conditions to be met before they can be lased. The carrier inversion distribution in the active region must be met. The stimulated radiation light oscillates back and forth in the resonant cavity, and the propagation in the gain medium amplifies the light. The threshold condition is met so that the gain is greater than the loss, and finally the laser is output.

[0004] Nitride semiconductor lasers have the following problems: the fast axis divergence angle of the violet laser is too large, which causes the cavity surface power density to be too high, increases the cavity surface load, and thus reduces the optical power output of the violet light. At the same time, the refractive index dispersion and light field dissipation cause the light beam to deviate from the Gaussian beam, causing the light field substrate mode to leak, and the substrate mode suppression efficiency is low, which reduces the far-field FFP image quality and laser coherence. Summary of the invention

[0005] The present invention proposes a gallium nitride-based semiconductor violet laser with a lower waveguide layer with a low fast-axis divergence angle, modulates the thickness and refractive index change curve of the lower waveguide layer, makes the light beam close to a Gaussian beam, reduces the fast-axis divergence angle and cavity surface power density, reduces the cavity surface load and substrate mode leakage, and improves the optical power, coherence and far-field FFP image quality of the laser.

[0006] The present invention provides a gallium nitride-based semiconductor violet laser with a low fast-axis divergence angle lower waveguide layer, which comprises, from bottom to top, a substrate, a lower cladding layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper cladding layer, wherein the lower waveguide layer is a low fast-axis divergence angle lower waveguide layer; the low fast-axis divergence angle lower waveguide layer is any one or any combination of InGaN, GaN, InN, and AlInGaN; and the peak rate electric field distribution of the low fast-axis divergence angle lower waveguide layer has a zigzag distribution.

[0007] Preferably, the peak rate electric field distribution of the waveguide layer under the low fast axis divergence angle shows an upward trend toward the lower cladding layer, and the rising angle is 40 to 90°.

[0008] Preferably, the peak velocity electric field distribution of the waveguide layer at the low fast axis divergence angle is approximately an inverse "L" type distribution, and the approximate function y=e x / x 2 Second quadrant curve distribution.

[0009] Preferably, the polarization optical phonon energy distribution of the waveguide layer at the low fast axis divergence angle has a zigzag distribution and increases toward the lower cladding layer, and the increase angle is 40 to 90 degrees.

[0010] Preferably, the polari-optical phonon energy distribution of the waveguide layer at the low fast axis divergence angle is approximately an inverse "L" type distribution, and the approximate function y=e x / x 2 Second quadrant curve distribution.

[0011] Preferably, the separation energy distribution of the waveguide layer at the low fast axis divergence angle is approximately an inverse "L" type distribution, and the approximate function y=e x / x 2 Second quadrant curve distribution.

[0012] Preferably, the heavy hole effective mass distribution of the waveguide layer at the low fast axis divergence angle is approximately an inverse "L" type distribution, and the approximate function y=e x / x 2 Second quadrant curve distribution.

[0013] Preferably, the active layer is a periodic structure composed of a well layer and a barrier layer, the number of periods is 3≥m≥1, and the well layer is any one 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 or the like. Any combination, with a thickness of 10 to 150 angstroms, and 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 to 200 angstroms.

[0014] Preferably, the lower cladding layer, the upper waveguide layer and the upper cladding 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.

[0015] Preferably, the substrate comprises 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 Any one of a / SiO2 composite substrate, a magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

[0016] Compared with the prior art, the gallium nitride-based semiconductor violet laser with a lower waveguide layer with a low fast-axis divergence angle provided by an embodiment of the present invention has the following beneficial effects: the present invention forms a lower waveguide layer with a low fast-axis divergence angle, modulates the thickness and refractive index change curve of the lower waveguide layer, makes the light beam close to a Gaussian beam, reduces the fast-axis divergence angle and cavity surface power density, reduces the cavity surface load and substrate mode leakage, and improves the optical power, coherence and far-field FFP image quality of the laser; at the same time, reduces the Auger recombination of the lower waveguide layer, the recombination of carriers with heterojunction interface states and surface states, reduces internal optical absorption losses, reduces the temperature rise of the laser, and improves the reliability and aging light attenuation of the laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of a gallium nitride-based semiconductor violet laser having a lower waveguide layer with a low fast-axis divergence angle according to an embodiment of the present invention;

[0018] Figure 2 It is a SIMS secondary ion mass spectrum of a gallium nitride-based semiconductor violet laser with a lower waveguide layer with a low fast-axis divergence angle according to an embodiment of the present invention;

[0019] Figure 3 This is a SIMS secondary ion mass spectrum of a gallium nitride-based semiconductor violet laser with a waveguide layer having a low fast-axis divergence angle according to an embodiment of the present invention (partially enlarged view);

[0020] Reference numerals: 100: substrate; 101: lower cladding layer; 102: lower waveguide layer; 103: active layer; 104: upper waveguide layer, 105: upper cladding layer. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In order to solve the above problems, a gallium nitride-based semiconductor violet laser with a lower waveguide layer with a low fast-axis divergence angle provided in an embodiment of the present application will be introduced and explained in detail through the following specific embodiments.

[0023] Reference Figure 1-3The present invention provides a gallium nitride-based semiconductor violet laser with a low fast-axis divergence angle lower waveguide layer, which includes, from bottom to top, a substrate 100, a lower cladding layer 101, a lower waveguide layer 102, an active layer 103, an upper waveguide layer 104, and an upper cladding layer 105. The lower waveguide layer 102 is a low fast-axis divergence angle lower waveguide layer 102; the low fast-axis divergence angle lower waveguide layer 102 is any one or any combination of InGaN, GaN, InN, and AlInGaN; the peak rate electric field distribution of the low fast-axis divergence angle lower waveguide layer 102 has a zigzag distribution.

[0024] In the present invention, the peak rate electric field distribution of the waveguide layer 102 at the low fast axis divergence angle shows an upward trend toward the lower cladding layer 101, and the rising angle is 40 to 90 degrees. The peak rate electric field distribution of the waveguide layer 102 at the low fast axis divergence angle is approximately a reverse "L" type distribution, and the approximate function y=e x / x 2 Second quadrant curve distribution.

[0025] In the present invention, the polarization optical phonon energy distribution of the waveguide layer 102 at the low fast axis divergence angle has a zigzag distribution and rises toward the lower cladding layer 101, with an upward change angle of 40 to 90°. The polarization optical phonon energy distribution of the waveguide layer 102 at the low fast axis divergence angle is approximately a reverse "L" type distribution, and the approximate function y=e x / x 2 Second quadrant curve distribution.

[0026] In the present invention, the separation energy distribution of the waveguide layer 102 at the low fast axis divergence angle is approximately an inverse "L" type distribution, and the approximate function y=e x / x 2 The second quadrant curve distribution. The heavy hole effective mass distribution of the waveguide layer 102 at the low fast axis divergence angle is approximately an inverse "L" type distribution, and the approximate function y=e x / x 2 Second quadrant curve distribution.

[0027] The present invention forms a lower waveguide layer with a low fast-axis divergence angle, modulates the thickness and refractive index change curve of the lower waveguide layer 102, makes the light beam close to a Gaussian beam, reduces the fast-axis divergence angle and cavity surface power density, reduces the cavity surface load and substrate mode leakage, and improves the optical power, coherence and far-field FFP image quality of the laser. The specific data are shown in the following table:

[0028] UV laser project Conventional laser Laser of the present invention Range of change 1000H aging light decay 21％ 2.7％ -87％ Optical power(W) 3.01 4.17 39％ <![CDATA[Internal optical loss (cm -1 )]]> 17.2 7.6 -56％

[0029] In the present invention, the active layer 103 is a periodic structure composed of a well layer and a barrier layer, the number of periods is 3≥m≥1, and the well layer is any one 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. 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 to 200 angstroms.

[0030] In the present invention, the lower cladding layer 101, the upper waveguide layer 104, and the upper cladding 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, BN, and diamond.

[0031] In the present invention, the substrate 100 includes 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 Any one of a / SiO2 composite substrate, a magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

[0032] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A gallium nitride-based semiconductor violet laser having a lower waveguide layer with a low fast axis divergence angle, comprising, from bottom to top, a substrate (100), a lower cladding layer (101), a lower waveguide layer (102), an active layer (103), an upper waveguide layer (104), and an upper cladding layer (105), characterized in that: The lower waveguide layer (102) is a low fast axis divergence angle lower waveguide layer (102); the low fast axis divergence angle lower waveguide layer (102) is any one or any combination of InGaN, GaN, InN, and AlInGaN; the peak rate electric field distribution of the low fast axis divergence angle lower waveguide layer (102) has a zigzag distribution.

2. The gallium nitride-based semiconductor violet laser with a waveguide layer having a low fast axis divergence angle according to claim 1, characterized in that: The peak rate electric field distribution of the waveguide layer (102) at the low fast axis divergence angle shows an upward trend toward the lower cladding layer (101), and the upward change angle is 40 to 90 degrees.

3. The gallium nitride-based semiconductor violet laser with a waveguide layer having a low fast axis divergence angle according to claim 2, characterized in that: The peak velocity electric field distribution of the waveguide layer (102) at the low fast axis divergence angle is approximately an inverse "L" type distribution, and the approximate function y=e x / x 2 Second quadrant curve distribution.

4. The gallium nitride-based semiconductor violet laser with a waveguide layer having a low fast axis divergence angle according to claim 1, characterized in that: The polarized optical phonon energy distribution of the waveguide layer (102) at the low fast axis divergence angle has a zigzag distribution and shows an upward trend toward the lower cladding layer (101), and the upward change angle is 40 to 90 degrees.

5. The gallium nitride-based semiconductor violet laser with a waveguide layer having a low fast axis divergence angle according to claim 4, characterized in that: The polarized optical phonon energy distribution of the waveguide layer (102) at the low fast axis divergence angle is approximately an inverse "L" type distribution, and the approximate function y=e x / x 2 Second quadrant curve distribution.

6. The gallium nitride-based semiconductor violet laser with a waveguide layer having a low fast axis divergence angle according to claim 1, characterized in that: The separation energy distribution of the waveguide layer (102) at the low fast axis divergence angle is approximately an inverse "L" type distribution, and the approximate function y=e x / x 2 Second quadrant curve distribution.

7. The gallium nitride-based semiconductor violet laser with a waveguide layer having a low fast axis divergence angle according to claim 1, characterized in that: The heavy hole effective mass distribution of the waveguide layer (102) at the low fast axis divergence angle is approximately an inverse "L" type distribution, and the approximate function y=e x / x 2 Second quadrant curve distribution.

8. The gallium nitride-based semiconductor violet laser with a waveguide layer having a low fast axis divergence angle according to claim 1, characterized in that: The active layer (103) is a periodic structure composed of a well layer and a barrier layer, the number of periods is 3≥m≥1, and the well layer is any one 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 or the like. Any combination, with a thickness of 10 to 150 angstroms, and 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 to 200 angstroms.

9. The gallium nitride-based semiconductor violet laser with a waveguide layer having a low fast axis divergence angle according to claim 1, characterized in that: The lower cladding layer (101), the upper waveguide layer (104), and the upper cladding 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, BN, and diamond.

10. The gallium nitride-based semiconductor violet laser with a waveguide layer having a low fast axis divergence angle according to claim 1, characterized in that: The substrate (100) includes 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 Any one of a / SiO2 composite substrate, a magnesium aluminum spinel MgAl2O4, MgO, ZnO, ZrB2, LiAlO2 and LiGaO2 composite substrate.

Images