CN112713507A - GaN-based echo wall laser based on porous DBR (distributed Bragg Reflector), and preparation method and application thereof - Google Patents
GaN-based echo wall laser based on porous DBR (distributed Bragg Reflector), and preparation method and application thereof Download PDFInfo
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
- H01S5/12—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region the resonator having a periodic structure, e.g. in distributed feedback [DFB] lasers
- H01S5/125—Distributed Bragg reflector [DBR] lasers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/30—Structure or shape of the active region; Materials used for the active region
- H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/30—Structure or shape of the active region; Materials used for the active region
- H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
- H01S5/3407—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers characterised by special barrier layers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/30—Structure or shape of the active region; Materials used for the active region
- H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
- H01S5/343—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser
- H01S5/34333—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser
Abstract
A GaN-based echo wall laser based on porous DBR, its preparation method and application, the GaN-based echo wall laser includes a substrate; the buffer layer is arranged on the substrate, and the periphery of the buffer layer is etched downwards to form a convex part; a porous DBR layer disposed on the convex portion for optical field confinement; an n-type doped GaN layer disposed on the porous DBR layer; an active layer disposed on the n-type doped GaN layer; an electron blocking layer disposed on the active layer; and a p-type doped GaN layer disposed on the electron blocking layer. The bottom porous DBR reflector adopted by the invention has good limiting effect in the vertical direction on the optical field of the echo wall microcavity, does not cause leakage of part of the optical field to the substrate direction, and the prepared echo wall laser has lower threshold power density.
Description
Technical Field
The invention belongs to the field of laser light sources, and particularly relates to a GaN-based echo wall laser based on a porous DBR (distributed Bragg reflector) and a preparation method and application thereof.
Background
With the rapid development of information, the integration degree of electronic chips is continuously improved, but the resulting interconnect parasitic effect can cause signal delay, which is a non-negligible bottleneck for further improving the information transmission processing. The photoelectron integration using light as carrier for information processing can perform information processing better and quickly because it is not affected by parasitic effect of electric interconnection. For the optoelectronic integration technology, the on-chip integrated laser can provide an efficient light source for an optical system to ensure normal transmission of signals, and in order to meet the requirements of high integration level and low power consumption of optoelectronic integration, a small-sized and low-power-consumption on-chip light source is required. The echo wall laser is an ideal light source due to the advantages of small volume, low threshold value, high quality factor, low power consumption and simple preparation.
At present, there are many problems to be solved when the distance of GaN (gallium nitride) -based echo wall laser becomes an on-chip integrated light source, and how to reduce the lasing threshold is one of the most important problems. Since the lasing threshold is directly related to the limiting capability of the device structure of the laser on the optical field of the active region, the lasing threshold is reduced due to the high optical field limiting capability. Therefore, the optimized design of the laser device structure and the improvement of the optical field limiting effect of the laser device structure are beneficial to the realization of a low-threshold optical pump and even an electric pump GaN-based echo wall laser. In order to improve the light limiting capability of the GaN-based echo wall resonant cavity, two technical approaches are mainly adopted: one is to use epitaxial growth of GaN/AlXGa1-xThe N (aluminum gallium nitrogen) superlattice is used as a bragg reflector, however, due to 2.4% lattice mismatch between GaN and AlN (aluminum nitride), the epitaxy difficulty is high, and the problem is more serious under high Al composition. Furthermore, to achieve high reflectivity of the mirror, the low index difference often needs to be compensated by increasing the number of periods of the DBR (aluminum nitride), while epitaxy of GaN/AlGaN DBRs for multiple periods would further increase the difficulty of epitaxy. In addition, the introduction of an air gap under the active region by gallium nitride selective etching to increase the refractive index difference at the vertical interface still presents some problems. Firstly, for the echo wall resonant cavity with sapphire substrate, an InGaN (indium gallium nitride) superlattice needs to be additionally designed below an active region, the superlattice needs to be designed with the stress effect brought by corrosion and epitaxy at the same time, and the epitaxy is increasedDifficulty. Secondly, the contact area between the support material for connecting the microdisk and the substrate and the microdisk is very small, and the electrical and thermal contact is poor, so that the later-stage realization of an electrical device is not facilitated. While some of the modes may also leak into the substrate along the support material.
In recent years, DBR based on lateral porous GaN material and its application in nitride optoelectronic devices have attracted attention. The porous GaN-DBR only needs to regulate and control the doping concentration of gallium nitride in different epitaxial periods, and then selective corrosion is carried out on the heavily doped region by utilizing an electrochemical method, so that transverse porous GaN is formed, and the refractive index is changed. Thus, larger refractive index difference can be formed with the non-corroded lightly doped GaN layer, so that a periodic porous GaN-DBR structure is obtained, and the GaN-based echo wall resonant cavity with high quality factor is expected to be realized. In addition, the novel echo wall resonant cavity only needs the GaN layer with the epitaxial doping concentration alternating between light and heavy, so that the problem of lattice mismatch does not exist, and the stress in an epitaxial structure is released. In addition, the bottom reflector of the porous GaN-DBR and the active region can form better electrical and thermal contact, and the electric pump device is favorably realized.
Disclosure of Invention
In view of the above, it is a primary objective of the present invention to provide a GaN-based whispering gallery laser based on porous DBR, its manufacturing method and its application, so as to at least partially solve at least one of the above-mentioned technical problems.
In order to achieve the above object, as one aspect of the present invention, there is provided a porous DBR-based GaN-based backwall laser including:
a substrate;
the buffer layer is arranged on the substrate, and the periphery of the buffer layer is etched downwards to form a convex part;
a porous DBR layer disposed on the convex portion for optical field confinement;
an n-type doped GaN layer disposed on the porous DBR layer for providing electrons;
an active layer disposed on the n-type doped GaN layer;
the electron blocking layer is arranged on the active layer and used for blocking electron overshoot and improving the radiation recombination uniformity of the quantum well; and
and a p-type doped GaN layer disposed on the electron blocking layer for providing holes.
As another aspect of the present invention, there is also provided a method for manufacturing the laser device as described above, including:
as a further aspect of the present invention, there is also provided an application of the laser device as described above or the laser device obtained by the preparation method as described above in the field of optoelectronic integration.
Based on the technical scheme, compared with the prior art, the GaN-based echo wall laser based on the porous DBR, the preparation method and the application thereof have at least one of the following advantages:
1. the bottom porous DBR reflector adopted by the invention has good limiting effect in the vertical direction on the optical field of the echo wall microcavity, and can not cause leakage of part of the optical field to the substrate direction, so that the threshold power density of the echo wall laser prepared by the invention is lower;
2. according to the invention, because the porous DBR lower reflector is embedded in the whole epitaxial structure, compared with a pillar structure, the porous DBR lower reflector has the advantages of larger contact area with an active layer, better mechanical property and better heat dissipation performance;
3. because the porous DBR comprises the n-type GaN laminated layer, the conductivity is better, and the realization of an electric pump echo wall laser is facilitated.
Drawings
Fig. 1 is a schematic structural diagram of an echo wall optical pump laser according to an embodiment of the present invention;
FIG. 2 is a flow chart of the preparation of an echo wall optical pump laser according to an embodiment of the present invention;
FIG. 3 is a top view of an echo wall optical pump laser according to an embodiment of the present invention;
fig. 4 is a scanning electron microscope picture of the porous DBR of the echo wall optical pump laser according to the embodiment of the present invention.
Description of reference numerals:
1-a substrate; 2-a buffer layer; a 3-DBR layer; a 4-n type doped GaN layer; 5-an active layer; 6-electron blocking layer; 7-p type doped GaN layer, 8-current spreading layer.
Detailed Description
In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.
It is an object of the present invention to provide a low threshold (less than 80 kw/cm) which facilitates optoelectronic integration2) The GaN-based echo wall optical pump laser also provides a method for preparing the device, and the light and heavy doped layers which are alternately stacked are directly grown in the epitaxial structure of the echo wall laser and are converted into a DBR structure with alternately stacked porous layers and non-porous layers through transverse electrochemical corrosion, so that the bottom reflector of the echo wall laser is embedded with high quality. On the basis, the device of the echo wall laser is prepared by adopting the processes of common photoetching, metal evaporation and plasma etching.
The invention discloses an echo wall optical pump laser, which comprises:
a substrate;
the buffer layer is arranged on the substrate, and the periphery of the buffer layer is etched downwards to form a convex part;
a porous DBR layer disposed on the convex portion for optical field confinement;
an n-type doped GaN layer disposed on the porous DBR layer for providing electrons;
an active layer disposed on the n-type doped GaN layer;
the electron blocking layer is arranged on the active layer and used for blocking electron overshoot and improving the radiation recombination uniformity of the quantum well; and
and a p-type doped GaN layer disposed on the electron blocking layer for providing holes.
Wherein the substrate is a planar substrate or a graphic substrate;
wherein, the substrate is made of any one of sapphire, silicon, gallium nitride or silicon carbide.
Wherein the buffer layer includes a GaN nucleation layer and an unintentionally doped GaN layer.
Wherein the height of the raised portion is less than the thickness of the buffer layer;
wherein, the convex part is a cylindrical or circular table surface.
The porous DBR layer forms a lower reflector of the GaN-based echo wall laser;
wherein the structure of the porous DBR layer comprises a DBR formed by alternately stacking a nitride porous layer and a non-porous layer;
wherein, the material that the porous DBR layer adopted includes any one or two combinations of GaN, AlGaN.
Wherein the laser further comprises a current spreading layer for electrochemically etching to form the porous DBR layer, the current spreading layer being disposed between the porous DBR layer and the buffer layer;
the current spreading layer is made of a material including n-type doped GaN.
Wherein the dopant of the n-type doped GaN layer comprises silane;
the active layer is made of materials including an InGaN/GaN multi-quantum well structure;
the electron blocking layer is made of undoped AlGaN or p-type doped AlGaN;
wherein the dopant of the p-type doped AlGaN comprises a magnesium metallocene.
The invention also discloses a preparation method of the laser, which comprises the following steps:
(1) sequentially growing a buffer layer, alternately stacked doping layers, an n-type doped GaN layer, an active layer, an electron blocking layer and a p-type doped GaN layer on a substrate;
(2) carrying out transverse corrosion on the alternately stacked doped layers to form a porous DBR layer;
(3) arranging a mask on the top of the device obtained in the step (2);
(4) etching the p-type doped GaN layer, the electron blocking layer, the active layer, the n-type doped layer and the porous DBR layer to the buffer layer by taking the mask obtained in the step (3) as a template;
(5) and (4) removing the mask in the step (4) to obtain the device, namely the laser.
Wherein, the etching method for etching to form the porous DBR layer in the step (2) comprises adopting an electrochemical etching method;
wherein, the pattern shape of the mask plate in the step (3) comprises a circle or a circular ring;
the preparation method of the mask in the step (3) comprises the following steps: spin-coating photoresist on the surface of the porous DBR layer obtained in the step (2), then defining a circular or annular pattern on the spin-coated photoresist layer by adopting a photoetching technology, then evaporating metal nickel on the photoresist, stripping metal by utilizing a blue film to form a disc or a ring of the metal nickel, and finally removing the residual photoresist;
wherein, the etching method in the step (4) comprises a plasma enhanced etching method.
The invention also discloses the application of the laser or the laser prepared by the preparation method in the field of photoelectron integration.
In an exemplary embodiment of the present invention, a porous DBR-based GaN-based whispering gallery optical pump laser includes:
a substrate, wherein the material of the substrate is sapphire, silicon, gallium nitride or silicon carbide;
the buffer layer is positioned on the upper surface of the substrate, a cylindrical or circular mesa is formed by etching downwards the periphery of the buffer layer, the depth of the mesa is smaller than the thickness of the buffer layer, and a convex part is arranged in the middle of the buffer layer;
a bottom porous DBR layer on the raised portion of the buffer layer;
the n-type doped GaN layer is positioned on the upper surface of the bottom porous DBR layer;
the active layer is positioned on the upper surface of the n-type doped GaN layer;
the electron blocking layer is positioned on the upper surface of the active layer;
and the p-type doped GaN layer is positioned on the upper surface of the electron blocking layer.
And the bottom porous DBR layer forms a lower reflector of the GaN-based echo wall laser.
Wherein, the structure of the bottom porous DBR layer is a DBR formed by alternately stacking a nitride porous layer and a non-porous layer.
The invention also provides a preparation method of the GaN-based echo wall optical pump laser based on the porous DBR, which comprises the following steps:
step 1: sequentially growing a buffer layer, alternately stacked light and heavy doping layers, an n-type doped GaN layer, an active layer, an electron blocking layer and a p-type doped GaN layer on a substrate, wherein the substrate is made of sapphire, silicon, gallium nitride or silicon carbide;
step 2: performing transverse corrosion on the alternately stacked light and heavy doped layers by adopting an electrochemical corrosion method, and converting the light and heavy doped layers into bottom porous DBR layers with alternately stacked porous layers and non-porous layers;
and step 3: spin-coating a photoresist on the surface of the porous DBR layer obtained in the step 2, defining a circular or annular pattern on the spin-coated photoresist layer by adopting a photoetching technology, then evaporating metal nickel on the photoresist, stripping metal by utilizing a blue film to form a circular or annular metal nickel layer, and finally removing the residual photoresist;
and 4, step 4: using a disc or a ring of metallic nickel as a mask, and adopting a plasma enhanced etching technology to etch the p-type doped GaN layer, the electron barrier layer, the active layer, the n-type doped layer, the bottom porous DBR layer and the buffer layer downwards in sequence, so that the pattern defined in the step 3 is transferred to other layers above the substrate;
and 5: and removing the metal mask to obtain a micro-cavity structure of a disc or a ring, namely the laser, and finishing the preparation of the device.
And the bottom porous DBR layer forms a lower reflector of the GaN echo wall laser.
Wherein, the structure of the bottom porous DBR layer is a DBR formed by alternately stacking a nitride porous layer and a non-porous layer.
The technical solution of the present invention is further illustrated by the following specific embodiments in conjunction with the accompanying drawings. It should be noted that the following specific examples are given by way of illustration only and the scope of the present invention is not limited thereto.
Referring to fig. 1, a GaN-based echo-wall optical pump laser based on a porous DBR of the present embodiment includes:
a substrate 1, which is a planar or graphic substrate, wherein the substrate 1 is made of sapphire, silicon, gallium nitride or silicon carbide;
and the buffer layer 2 is positioned on the upper surface of the substrate 1 and consists of a low-temperature (less than 750 ℃) GaN nucleation layer and an unintended doped GaN layer, the GaN nucleation layer grows at low temperature firstly and then the unintended doped GaN layer grows at high temperature (more than 800 ℃) by taking high-purity pure ammonia gas as a nitrogen source and trimethyl gallium or triethyl gallium as a Ga source. A cylindrical or circular mesa is formed on the periphery of the buffer layer in a downward etching mode, the depth of the mesa is smaller than the thickness of the buffer layer, and a convex part is arranged in the middle of the buffer layer;
a bottom porous DBR layer 3 positioned on the upper convex part of the buffer layer 2, wherein the material of the bottom porous DBR layer 3 is a multi-period DBR formed by alternately stacking porous layers and non-porous layers of GaN, AlGaN or a nitride material combination;
wherein the bottom porous DBR layer 3 is obtained by electrochemically etching alternately stacked lightly and heavily doped layers, wherein the typical doping concentration of the heavily doped layers is 1 x 1019cm-3Typical concentration of lightly doped layer 5 × 1016cm-3The number of cycles of the bottom porous DBR layer 3 is 20;
an n-type GaN layer is grown between the bottom porous DBR layer 3 and the buffer layer 2 and is used as a current expansion layer specially used for forming the bottom porous DBR layer 3 through electrochemical corrosion;
an n-type doped GaN layer 4, the dopant being silane, typically with a doping concentration of 1 × 1018cm-3On the upper surface of the bottom porous DBR layer 3;
the active layer 5 is manufactured on the upper surface of the n-type doped GaN layer 4, and the active layer 5 is of an InGaN/GaN multi-quantum well structure;
an electron blocking layer 6, located on the upper surface of the active layer 5, wherein the electron blocking layer 6 is made of AlGaN material and can be doped p-type, and the dopant is magnesium cyclopentadienyl;
the p-type doped GaN layer 7 is positioned on the upper surface of the electron blocking layer 6;
referring to fig. 2 in combination with fig. 1 and fig. 3, the present invention provides a method for manufacturing a GaN-based echo wall optical pump laser based on a porous DBR, which includes the following steps:
step 1: sequentially growing buffer layers 2 and alternately stacked light and heavy doped layers (light doping concentration is not more than 1 x 10) on a substrate 118cm-3Heavily doped at 5X 1018-1×1020cm-3) The GaN-based light-emitting diode comprises an n-type doped GaN layer 4, an active layer 5, an electron blocking layer 6, a p-type doped GaN layer 7 and a current expansion layer 8; as shown in a in fig. 2.
The substrate 1 is made of sapphire, silicon, gallium nitride or silicon carbide, and an n-type GaN layer is grown between the light and heavy doping layers and the buffer layer 2 which are alternately stacked and is used as a current expansion layer specially used for forming the porous DBR by electrochemical corrosion;
step 2: the alternately stacked lightly and heavily doped layers are etched laterally by electrochemical etching to convert them into the bottom porous DBR layer 3 with alternately stacked porous and non-porous layers, as shown in fig. 2 b.
The material of the bottom porous DBR layer 3 is a multi-period DBR formed by alternately stacking a nitride porous layer and a non-porous layer, the constituent material of the multi-period DBR is GaN, AlGaN, or a combination material of the above materials, and a scanning electron microscope image of the DBR layer is shown in fig. 4.
And step 3: and (3) spin-coating a photoresist on the surface of the porous GaN wafer obtained in the step (2), wherein the photoresist is a negative photoresist, then defining a circular or annular pattern on the spin-coated photoresist layer by adopting a photoetching technology, then evaporating metallic nickel on the wafer spin-coated with the photoresist by utilizing an electron beam evaporation technology, then pasting a blue film on metal, stripping unnecessary metal by utilizing the adhesive force of the blue film and the metal to form a disc or a ring of the metallic nickel, and finally removing the residual photoresist to form a mask plate, as shown in a diagram c in fig. 2.
And 4, step 4: and (2) etching the porous GaN epitaxial wafer obtained in the step (2) by using the metal pattern prepared in the step (3) as a hard mask by adopting a plasma enhanced etching technology, and sequentially etching the porous GaN epitaxial wafer from top to bottom to the buffer layer 2, wherein the porous GaN epitaxial wafer comprises a p-type doped GaN layer 7, an electronic barrier layer 6, an active layer 5, an n-type doped layer 4 and a bottom porous DBR layer 3, and the etching depth of the buffer layer 2 is smaller than the thickness of the buffer layer. After the etching is completed, the pattern defined in step 3 is transferred to other layers above the substrate, as shown in d of fig. 2.
And 5: attaching a blue film to the metal-evaporated surface of the wafer obtained in the step 4, forcibly tearing off the blue film, stripping most of the redundant metal except the defined pattern, and removing the redundant photoresist by using a film remover to finally obtain the GaN-based whispering gallery optical pump laser, as shown in a graph e in the figure 2; the p-type doped GaN layer 7 and the buffer layer 2 are exposed to air and have a circular shape (as shown in a in fig. 3) or a circular ring pattern (as shown in B in fig. 3) in a plan view.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. An echo-wall optical pump laser comprising:
a substrate;
the buffer layer is arranged on the substrate, and the periphery of the buffer layer is etched downwards to form a convex part;
a porous DBR layer disposed on the convex portion for optical field confinement;
an n-type doped GaN layer disposed on the porous DBR layer for providing electrons;
an active layer disposed on the n-type doped GaN layer;
the electron blocking layer is arranged on the active layer and used for blocking electron overshoot and improving the radiation recombination uniformity of the quantum well; and
and a p-type doped GaN layer disposed on the electron blocking layer for providing holes.
2. The laser of claim 1,
the substrate is a planar substrate or a pattern substrate;
the substrate is made of any one of sapphire, silicon, gallium nitride or silicon carbide.
3. The laser of claim 1,
the buffer layer includes a GaN nucleation layer and an unintentionally doped GaN layer.
4. The laser of claim 1,
the height of the convex part is smaller than the thickness of the buffer layer;
the convex part is a cylindrical or circular ring table surface.
5. The laser of claim 1,
the porous DBR layer forms a lower reflector of the GaN-based echo wall laser;
the structure of the porous DBR layer comprises a DBR formed by alternately stacking a nitride porous layer and a non-porous layer;
the material adopted by the porous DBR layer comprises any one or two combinations of GaN and AlGaN.
6. The laser of claim 1,
the laser further includes a current spreading layer for electrochemically etching to form the porous DBR layer, the current spreading layer being disposed between the porous DBR layer and the buffer layer;
the current spreading layer is made of a material including n-type doped GaN.
7. The laser of claim 1,
the dopant of the n-type doped GaN layer comprises silane;
the active layer is made of InGaN/GaN multi-quantum well structure;
the electron blocking layer is made of undoped AlGaN or p-type doped AlGaN;
the dopant of the p-type doped A1GaN includes a magnesium metallocene.
8. A method of making a laser as claimed in any one of claims 1 to 7, comprising:
(1) sequentially growing a buffer layer, alternately stacked doping layers, an n-type doped GaN layer, an active layer, an electron blocking layer and a p-type doped GaN layer on a substrate;
(2) carrying out transverse corrosion on the alternately stacked doped layers to form a porous DBR layer;
(3) arranging a mask on the top of the device obtained in the step (2);
(4) etching the p-type doped GaN layer, the electron blocking layer, the active layer, the n-type doped layer and the porous DBR layer to the buffer layer by taking the mask obtained in the step (3) as a template;
(5) and (4) removing the mask in the step (4) to obtain the device, namely the laser.
9. The method according to claim 8,
the etching method for etching to form the porous DBR layer in the step (2) comprises the steps of adopting an electrochemical etching method;
the pattern shape of the mask in the step (3) comprises a circle or a circular ring;
the preparation method of the mask in the step (3) comprises the following steps: spin-coating photoresist on the surface of the porous DBR layer obtained in the step (2), then defining a circular or annular pattern on the spin-coated photoresist layer by adopting a photoetching technology, then evaporating metal nickel on the photoresist, stripping metal by utilizing a blue film to form a disc or a ring of the metal nickel, and finally removing the residual photoresist;
the etching method in the step (4) comprises a plasma enhanced etching method.
10. Use of a laser according to any of claims 1 to 7 or a laser obtained by a method according to any of claims 8 to 9 in the field of optoelectronic integration.
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