Photonic crystal surface emitting laser and preparation method thereof

Abstract

The present application relates to the field of laser preparation technology and provides a photonic crystal surface emitting laser and its preparation method. The preparation method comprises: sequentially growing an n-type doping layer, a p-type separate confinement layer and a p-type confinement layer on a GaAs substrate. + / n + Tunnel junction; in p + / n + The tunnel junction is prepared by patterning a mask structure; the patterning mask structure includes a plurality of preset patterns; etching the p + / n + Tunnel junctions are formed to produce multiple photonic crystals; an n-type cladding layer, an undoped active layer, and a p-type cladding layer are sequentially grown on the photonic crystals; a p-type electrode is grown on the p-type cladding layer; and an n-type electrode is grown on the GaAs substrate. This preparation method effectively solves the SHB problem. Multiple photonic crystals can be arranged in different ways to form patterns that achieve the desired light emission method. This allows light to be emitted in various directions, meeting the different light emission characteristics required by photonic crystal surface emitting lasers and ensuring the laser's performance.

Description

Technical Field

[0001] The present application relates to the technical field of laser preparation, and in particular to a photonic crystal surface emitting laser and a preparation method thereof. Background Art

[0002] The photonic crystal surface emitting laser (PCSEL) is a new type of semiconductor laser based on a two-dimensional photonic crystal structure. It achieves in-plane resonance and perpendicular surface laser emission through periodic refractive index modulation. The photonic crystal structure in PCSELs is the main component that realizes the laser's performance.

[0003] Currently, the fabrication process for PCSEL lasers typically involves using photolithography and etching processes to form various patterns of "pores" on the surface of a semiconductor wafer to construct a photonic crystal structure. A secondary epitaxial growth process is then used to cover these "pores" with an epitaxial layer of appropriate composition and thickness, completing the laser heterostructure. However, the "pores" etched into the semiconductor surface make the wafer surface uneven, which greatly complicates secondary epitaxy. Furthermore, the shape of the "pores" can be severely distorted after secondary epitaxy. Furthermore, the buried "pores" can trap gases or liquids, which can rupture or explode during subsequent heat treatment, triggering spatial hole burning (SHB), which can severely impact the performance of the PCSEL laser.

[0004] Therefore, there is an urgent need for a PCSEL laser that can solve the SHB problem to ensure performance. Summary of the Invention

[0005] The present application provides a photonic crystal surface emitting laser and a preparation method thereof, so as to solve the technical problem of poor performance of PCSEL laser caused by SHB problem.

[0006] The first aspect of the present application provides a method for preparing a photonic crystal surface emitting laser, comprising: sequentially growing an n-type doped layer, a p-type separate confinement layer and a p-type confinement layer on a GaAs substrate; + / n + Tunnel junction; in p + / n + The tunnel junction is prepared by patterning a mask structure; the patterning mask structure includes a plurality of preset patterns; etching the p + / n + Tunnel junctions are formed to obtain multiple photonic crystals; wherein the multiple photonic crystals are arranged along at least two directions; an n-type cladding layer, an undoped active layer and a p-type cladding layer are sequentially grown on the photonic crystals; a p-type electrode is grown on the p-type cladding layer; and an n-type electrode is grown on a GaAs substrate.

[0007] In some feasible implementations, etching p according to a preset pattern + / n + Tunnel junction to obtain multiple photonic crystals, including: etching the p + / n + Tunnel junction; removing the patterned mask structure of the preset pattern to obtain a plurality of photonic crystals; wherein the photonic crystal includes the preset pattern.

[0008] In some feasible implementations, the preset graphics include one or more of a circle, a triangle, a square, an ellipse, or a pentagon.

[0009] In some feasible implementations, the multiple photonic crystals have the same shape and are arranged in an array.

[0010] In some feasible implementations, the width of the photonic crystal is 10 nm-200 nm; and the distance between the centers of any two adjacent photonic crystals is 50 nm-300 nm.

[0011] In some possible implementations, p + / n + The thickness of the tunnel junction is greater than or equal to 10 nm.

[0012] In some feasible implementations, the method for manufacturing a photonic crystal surface emitting laser further includes: patterning the p-type electrode and / or the n-type electrode.

[0013] In some feasible implementations, the material of the p-type electrode includes gold or aluminum; the material of the n-type electrode includes gold or aluminum.

[0014] In some possible implementations, p + / n + The doping level of the tunnel junction is heavily doped greater than or equal to 10 19 cm -3 .

[0015] The first aspect of the present application provides a method for preparing a photonic crystal surface emitting laser, which provides a method for preparing a photonic crystal by a coupling mechanism different from the etching "pore" method. + / n +Multiple photonic crystals are formed in a tunnel junction manner, and an n-type cladding layer is used to cover the photonic crystals to form a microcurrent injection zone, thereby obtaining a semiconductor heterostructure laser. The multiple photonic crystals in this preparation method can be arranged in different forms to form a pattern that can achieve the desired light emission method. Light can be emitted in all directions to meet the different light emission characteristics of the photonic crystal surface emitting laser and ensure the performance of the laser. It can also achieve the interaction of light waves in photonic crystals with different arrangements to produce lasers with different characteristics, thereby realizing functions such as beam shaping, beam steering, and high-power short pulse generation, and improving conversion efficiency.

[0016] The second aspect of the present application provides a photonic crystal surface emitting laser, comprising: a GaAs substrate; an n-type doping layer and a p-type separate confinement layer sequentially arranged on the GaAs substrate; a plurality of photonic crystals arranged on the p-type separate confinement layer; wherein the plurality of photonic crystals are arranged along at least two directions, and the cross-sectional shape of the photonic crystals is a preset pattern, and the plurality of photonic crystals are composed of p-type confinement layers grown on the p-type separate confinement layer. + / n + The tunnel junction is obtained by etching; the n-type cladding layer, the undoped active layer and the p-type cladding layer are sequentially arranged on multiple photonic crystals; the p-type electrode is arranged on the p-type cladding layer; and the n-type electrode is arranged on the GaAs substrate.

[0017] The photonic crystal surface emitting laser provided in the second aspect of the present application is prepared by the preparation method of the photonic crystal surface emitting laser provided in the first aspect. Therefore, its beneficial technical effects can be referred to the first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 This is a flow chart of a method for preparing a photonic crystal surface emitting laser provided in an embodiment of the present application;

[0020] Figure 2 This is one of the process flow charts for preparing a photonic crystal surface emitting laser provided in an embodiment of the present application;

[0021] Figure 3 1 is a structural diagram of a patterned mask structure provided in an embodiment of the present application;

[0022] Figure 4 This is a schematic structural diagram of a photonic crystal provided in an embodiment of the present application;

[0023] Figure 5 This is the second process flow chart of a preparation process of a photonic crystal surface emitting laser provided in an embodiment of the present application;

[0024] Figure 6 This is a partial schematic diagram of the light output path of a photonic crystal surface emitting laser provided in an embodiment of the present application.

[0025] Graphic mark:

[0026] 100, photonic crystal surface emitting laser; 10, GaAs substrate; 20, n-type doping layer; 30, p-type separate confinement layer; 40, p + / n + Tunnel junction; 41. Photonic crystal; 411. First photonic crystal; 412. Second photonic crystal; 413. Third photonic crystal; 414. Fourth photonic crystal; 415. Fifth photonic crystal; 416. Sixth photonic crystal; 417. Seventh photonic crystal; a1. Patterned mask structure; 50. N-type cladding layer; 60. Undoped active layer; 70. P-type cladding layer; 80. P-type electrode; 90. N-type electrode. DETAILED DESCRIPTION

[0027] The following will clearly describe the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, other embodiments obtained by ordinary technicians in this field without making any creative work are all within the scope of protection of this application.

[0028] Hereinafter, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified with "first," "second," etc., may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0029] In addition, in this application, directional terms such as "upper", "lower", "inner" and "outer" are defined relative to the orientation of the components in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, and they can change accordingly according to changes in the orientation of the components in the drawings.

[0030] In PCSEL lasers, photonic crystals are artificial materials with periodic dielectric structures that have unique control over the propagation behavior of light. By introducing photonic crystal structures into semiconductor materials, PCSELs can achieve precise control over key parameters such as laser mode, beam divergence angle, and wavelength. For example, in the field of optical communications, PCSELs can provide narrow-linewidth, single-mode output lasers, effectively improving the capacity and distance of signal transmission; in laser processing, they can generate high-power, high-energy-density beams, improving processing accuracy and efficiency. Compared to traditional lasers, the surface emission characteristics of PCSELs make it easier to implement two-dimensional array integration, greatly increasing output power and expanding the scope of application.

[0031] In the fabrication process of PCSEL lasers, photolithography and etching processes are typically used to form various patterns of "pores" on the surface of a semiconductor wafer to construct a photonic crystal structure. Then, through secondary epitaxial growth, these "pores" are covered with an epitaxial layer of appropriate composition and thickness to complete the laser heterostructure. This method attempts to utilize the periodic refractive index distribution formed by the "pores" to achieve coupling with light waves propagating in the heterostructure, thereby generating laser light with specific characteristics.

[0032] However, the "pores" etched into the semiconductor surface will make the wafer surface uneven, which brings great difficulties to the secondary epitaxy. The shape of the "pores" will be seriously distorted after the secondary epitaxy. In addition, the buried "pores" may capture gas or liquid. During the subsequent heat treatment process, these gases or liquids may rupture or explode, causing spatial hole burning (SHB), which seriously affects the performance of the PCSEL laser.

[0033] In order to solve the above technical problems, the embodiment of the present application provides a method for preparing a photonic crystal surface emitting laser, which can solve problems such as unevenness or distortion caused by "pores" in the epitaxial stage, and can effectively solve the SHB problem to ensure the performance of the photonic crystal surface emitting laser.

[0034] Figure 1 This is a flow chart of a method for preparing a photonic crystal surface emitting laser provided in an embodiment of the present application; Figure 2 This is one of the process flow charts for preparing a photonic crystal surface emitting laser provided in an embodiment of the present application.

[0035] Combine Figure 1 and Figure 2 As shown, the method for preparing the photonic crystal surface emitting laser provided in the embodiment of the present application can be implemented by the following steps S1 to S6.

[0036] Step S1: sequentially growing an n-type doped layer 20, a p-type separate confinement layer 30 and a p-type confinement layer 31 on a GaAs substrate 10. + / n + Tunnel junction 40.

[0037] The GaAs substrate 10 must meet cleanliness and flatness requirements to provide a good foundation for subsequent epitaxial growth.

[0038] In some feasible implementations, step S1 may include steps S11 to S14.

[0039] Step S11: cleaning and surface flattening the GaAs substrate 10.

[0040] The cleaning process may include using plasma water, alcohol or hydrogen peroxide to clean the surface of the GaAs substrate 10. The flatness process may include grinding or polishing the surface of the GaAs substrate 10.

[0041] Step S12 : growing an n-type doped layer 20 on the GaAs substrate 10 .

[0042] The n-type doped layer 20 may include one of n-type aluminum gallium arsenide (AlGaAs), n-type gallium arsenide (GaAs), or n-type gallium nitride (GaN). Of course, the n-type doped layer 20 may also have other structures. The growth quality of the n-type doped layer 20 can be controlled by growth parameters (such as temperature, gas flow rate, and time). The thickness of the n-type doped layer 20 is between 100 nanometers and 10 microns.

[0043] Step S13 : growing a p-type individual confinement layer 30 on the n-type doped layer 20 .

[0044] The p-type separate confinement layer 30 (Separate Confinement Heterostructure, SCH) can include one of p-type aluminum gallium arsenide (AlGaAs), p-type gallium nitride (GaN), p-type aluminum gallium nitride (AlGaN), or p-type InGaAsP (Indium Gallium Arsenide Phosphate). Of course, the p-type separate confinement layer 30 can also include other structures.

[0045] Step S14: growing p-type individual confinement layer 30 + / n + Tunnel junction 40.

[0046] Among them, p + / n + Tunnel junction 40 may include p + GaAs / n + Type InGaAsP, p + InGaAsP / n+ InP or p + AlGaN / n + One of the GaN types.

[0047] In some feasible implementations, the growth method in step S1 may include metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE), with a growth temperature in the range of 700°C to 800°C. The thickness and quality of the multiple structural layers can be controlled by controlling parameters such as the deposition temperature and gas flow rate.

[0048] In some possible implementations, p + / n + The doping level of the tunnel junction 40 is heavily doped to 10 19 cm -3 above, to enable electrons to tunnel through the thin boundary layer of the junction.

[0049] It is worth noting that precise control of p + / n + The thickness of the tunnel junction 40 and the specific doping level and the specific value of the heavy doping are used to form a refraction and gain composite distribution, thereby matching the use of the photonic crystal surface emitting laser.

[0050] In step S12 to step S14, the deposition techniques of different structural layers can be the same or different, and the deposition techniques can be adaptively adjusted according to the specific structure of the structural layer. Among them, different structural layers can be combined at will, for example, the n-type doped layer 20 can be n-type gallium arsenide (GaAs), the p-type separate confinement layer 30 can be p-type gallium nitride (GaN), p-type gallium nitride (GaN), etc. + / n + The tunnel junction 40 may include p+ type GaAs / n+ type InGaAsP. Alternatively, the n-type doped layer 20 may be n-type aluminum gallium nitride (AlGaN), the p-type separate confinement layer 30 may be p-type aluminum gallium nitride (AlGaN), p-type GaAs, and n-type InGaAsP. + / n + Tunnel junction 40 may include p + GaAs / n + Type InGaAsP. During the deposition process, the gases introduced to coordinate the reaction can be adjusted according to the specific structure of the structural layer.

[0051] That is to say, the specific structures of the n-type doped layer 20 and the p-type individual confinement layer 30 can be the same or different, and the n-type doped layer 20 and the p-type individual confinement layer 30 are different from each other. + / n +The specific structure of the tunnel junction 40 can be adjusted flexibly. After step S1 is completed, Figure 2 The structure shown in (a).

[0052] Step S2: In p + / n + The tunnel junction 40 is formed into a patterned mask structure a1, which includes a plurality of preset patterns.

[0053] In step S2, the patterned mask structure a1 may be a photoresist, and the photolithography technique is used to form a patterned mask structure a1 on the p + / n + The tunnel junction 40 is covered with a photoresist, and the designed preset pattern is transferred to the photoresist through processes such as exposure and development. The preset pattern can include one or more of a circle, a triangle, a square, an ellipse or a pentagon. In this way, photonic crystal structures with different filling factors can be realized. After step S2 is completed, the result is Figure 2 The structure shown in (b).

[0054] Figure 3 This is a structural schematic diagram of a graphic mask structure provided in an embodiment of the present application.

[0055] See also Figure 3 As shown, a plurality of preset patterns are arranged in an array, and the preset patterns are square. The preset patterns can be arranged in the form of three rows and four columns or four rows and three columns.

[0056] Step S3: Etching p according to the preset pattern + / n + The tunnel junction 40 is formed to obtain a plurality of photonic crystals 41 ; wherein the arrangement of the photonic crystals 41 is the same as the arrangement of the preset pattern.

[0057] In this implementation, step S3 can be implemented by the following steps S31 and S32.

[0058] Step S31: etching the p not covered by the preset pattern + / n + Tunnel junction 40.

[0059] In step S31, photolithography technology may be used to etch the non-preset pattern area, for example Figure 3 The dotted area shown has an etching depth of p + / n + The thickness of the tunnel junction 40. Thus, after the etching of the region indicated by the dotted line is completed, the top surface of the p-type individual confinement layer 30 is exposed.

[0060] Step S32: removing the patterned mask structure a1 of the preset pattern to obtain a plurality of photonic crystals 41; wherein the cross-sectional shape of the photonic crystals 41 includes the preset pattern.

[0061] In step S32, a removal agent may be used to remove the patterned mask structure a1. The selection of the removal agent may be adaptively adjusted according to the specific type of the patterned mask structure a1. For example, a sulfuric acid-hydrogen peroxide mixture, an ammonia-hydrogen peroxide mixture, or oxygen plasma may be used to remove the photoresist.

[0062] After the patterned mask structure a1 is removed, a plurality of photonic crystals 41 can be obtained. The photonic crystals 41 obtained by etching are three-dimensional structures, and the cross-sectional shape is a preset pattern, such as Figure 2 This method can solve the SHB problem caused by "air holes" in the epitaxial growth stage. The photonic crystal 41 prepared by this method is flat, free of air holes and distortion.

[0063] It is understandable that the shape of the photonic crystal 41 is related to a preset pattern. The preset pattern of the photonic crystal 41 to be prepared can be engraved on the patterned mask structure a1, and the photonic crystal 41 of the desired pattern can be obtained after etching.

[0064] Figure 4 This is a schematic structural diagram of a photonic crystal provided in an embodiment of the present application; Figure 4 (a) to (g) are schematic diagrams of the arrangement of different photonic structures.

[0065] See also Figure 4 As shown in (a), multiple photonic crystals 41 are arranged along two directions, and the multiple photonic crystals 41 have the same size and shape, and are all cubes.

[0066] See also Figure 4 As shown in (b), multiple photonic crystals 41 are arranged along two directions, and the multiple photonic crystals 41 have the same size and shape, and are all triangular prisms.

[0067] See also Figure 4As shown in (c), multiple photonic crystals 41 are arranged in two directions. The sizes and shapes of the multiple photonic crystals 41 are different. The photonic crystals 41 may include a first photonic crystal 411, a second photonic crystal 412, a third photonic crystal 413, a fourth photonic crystal 414, a fifth photonic crystal 415, and a sixth photonic crystal 416. Specifically, the first photonic crystal 411, the fifth photonic crystal 415, and the sixth photonic crystal 416 have the same size and shape, and are all cubes; the second photonic crystal 412, the third photonic crystal 413, and the fourth photonic crystal 414 have the same size and shape, and are all cuboids. The second photonic crystal 412 and the third photonic crystal 413 extend in the same direction, while the fourth photonic crystal 414 extends in a different direction than the second photonic crystal 412 and the third photonic crystal 413.

[0068] See also Figure 4 As shown in (d), multiple photonic crystals 41 are arranged in multiple directions. The multiple photonic crystals 41 have the same size and shape and are all cylindrical. The photonic crystals 41 may include a first photonic crystal 411, a second photonic crystal 412, a third photonic crystal 413, a fourth photonic crystal 414, a fifth photonic crystal 415, and a sixth photonic crystal 416. Specifically, the second photonic crystal 412, the third photonic crystal 413, the fourth photonic crystal 414, the fifth photonic crystal 415, and the sixth photonic crystal 416 may be arranged in a circular array with the first photonic crystal 411 as the center.

[0069] See also Figure 4 As shown in (e), multiple photonic crystals 41 are arranged in two directions. The sizes and shapes of the multiple photonic crystals 41 are different. The photonic crystals 41 may include a first photonic crystal 411, a second photonic crystal 412, a third photonic crystal 413, a fourth photonic crystal 414, a fifth photonic crystal 415, a sixth photonic crystal 416, and a seventh photonic crystal 417. Specifically, the first photonic crystal 411, the second photonic crystal 412, and the third photonic crystal 413 have the same size and shape, and are all triangular prisms; the fourth photonic crystal 414 and the fifth photonic crystal 415 have the same size and shape, and are all cubes; the sixth photonic crystal 416 is a cylinder; and the seventh photonic crystal 417 is a cuboid.

[0070] above Figure 4 As shown in (a) to (e), the p-type individual confinement layer 30 is circular in shape. In other examples, the p-type individual confinement layer 30 may also be square. The shape of the p-type individual confinement layer 30 is the same as that of the GaAs substrate 10 .

[0071] See also Figure 4 As shown in (f), multiple photonic crystals 41 are arranged in two directions, and the multiple photonic crystals 41 have the same size and shape, and are all cubes.

[0072] See also Figure 4 As shown in (g), the multiple photonic crystals 41 have the same size and shape. The photonic crystals 41 are cylindrical, and the multiple photonic crystals 41 can form the letter "A." In other words, the size, shape, and arrangement of the photonic crystals 41 can be flexibly adjusted. In other implementations, the multiple photonic crystals 41 can also be arranged in a non-array format to form a specific pattern.

[0073] In this way, the prepared photonic crystal 41 can be flexibly adjusted according to the use requirements of the photonic crystal surface emitting laser, and can form a special gain and refractive index modulation distribution to couple light waves in all directions, so that the laser emitted by the photonic crystal surface emitting laser can produce a variety of characteristics. The photonic crystal 41 is the key to the effective coupling of light waves propagating in the waveguide generated by the heterostructure, and can control parameters such as the laser mode and the beam divergence angle.

[0074] Specifically, etching p + / n + The method of forming the photonic crystal 41 by means of the tunnel junction 40 can minimize the height of the photonic crystal 41. In some feasible implementations, p + / n + The thickness of the tunnel junction 40 is greater than or equal to 10 nm, that is, p + / n + The minimum thickness of the tunnel junction 40 can be 10 nm. Thus, the minimum height of the prepared photonic crystal 41 can be 10 nm, thereby reducing the size of the photonic crystal 41 while ensuring the light extraction effect.

[0075] In some possible implementations, p + / n + The doping level of the tunnel junction 40 is heavily doped to 10 19 cm -3 above, to enable electrons to tunnel through the thin boundary layer of the junction.

[0076] It is worth noting that precise control of p + / n + The thickness of the tunnel junction 40 and the specific value of the doping level and the heavy doping level are adjusted to form a composite refraction and gain distribution, thereby matching the use requirements of the photonic crystal surface emitting laser.

[0077] In some possible implementations, see Figure 2In (c), the width d of the photonic crystal 41 can be in the range of 10 nm to 200 nm. The distance L between the centers of two adjacent photonic crystals 41 can be in the range of 50 nm to 300 nm. Properly setting the width of the photonic crystal 41 and the distance between two adjacent photonic crystals 41 can adjust the phase of the photonic crystal surface emitting laser and ensure the output power of the photonic crystal surface emitting laser.

[0078] For example, the width d of the photonic crystal 41 may be one of 10 nm, 75 nm, 100 nm, 125 nm, or 150 nm. Of course, the width d of the photonic crystal 41 may also be other sizes within a range of 10 nm to 200 nm.

[0079] For example, the distance L between the centers of two adjacent photonic crystals 41 may be 50 nm, 100 nm, 175 nm, 200 nm, 250 nm, or 300 nm. Of course, the distance L between the centers of two adjacent photonic crystals 41 may also be other sizes within the range of 50 nm to 300 nm.

[0080] It should be emphasized that the photonic crystal 41 obtained by this preparation method, in conjunction with the adjustment of size and position relationship, can realize the key to effective coupling of light waves propagating in the waveguide generated by the heterostructure, and can effectively achieve single-mode output.

[0081] Figure 5 This is the second process flow chart of a photonic crystal surface emitting laser preparation process provided in an embodiment of the present application.

[0082] Step S4 : sequentially growing an n-type cladding layer 50 , an undoped active layer 60 and a p-type cladding layer 70 on the photonic crystal 41 .

[0083] In some possible implementations, combined with Figure 1 、 Figure 2 and Figure 5 As shown, step S4 can be implemented by the following steps S41 to S43.

[0084] Step S41 : growing an n-type cladding layer 50 on the photonic crystal 41 .

[0085] In step S41, an n-type cladding layer 50 is grown synchronously on the surface of the photonic crystal 41 and the surface of the p-type individual confinement layer 30, so that the n-type cladding layer 50 can evenly cover the p-type individual confinement layer 30 and the photonic crystal 41. In this way, no pores or gaps are generated between the photonic crystal 41 and the n-type cladding layer 50, effectively improving the structural performance of the n-type cladding layer 50, thereby effectively ensuring the performance of the photonic crystal surface emitting laser. After the preparation in step S42 is completed, the photonic crystal 41 can be obtained. Figure 2The structure shown in (d) is shown in FIG. Here, the thickness of the n-type cladding layer 50 is greater than the height of the photonic crystal 41 .

[0086] In some feasible implementations, the n-type cladding layer 50 may include one of n-type gallium arsenide (GaAs), n-type gallium nitride (GaN), or n-type aluminum gallium nitride (AlGaN). Of course, the n-type cladding layer 50 may also include other structural layers with cladding functions.

[0087] Step S42 : growing an undoped active layer 60 on the n-type cladding layer 50 .

[0088] The undoped active layer 60 provides a location for subsequent electron-hole recombination and luminescence. The quality and performance of the undoped active layer 60 are directly related to the luminous efficiency and output power of the photonic crystal surface emitting laser (PCSEL). During the preparation process, various growth parameters, such as temperature, pressure, and gas composition, are strictly controlled to ensure that the undoped active layer 60 has a complete crystal structure, few defects, and a uniform thickness that meets the requirements of PCSELs.

[0089] The undoped active layer 60 may include one of indium gallium arsenide phosphide (InGaAsP), aluminum indium gallium arsenide (InGaAlAs), aluminum gallium arsenide (AlGaAs) or aluminum gallium indium phosphide (AlGaInP). Of course, the undoped active layer 60 may also include other structural layers.

[0090] After the preparation in step S42 is completed, Figure 5 The structure shown in (a).

[0091] Step S43 : growing a p-type cladding layer 70 on the undoped active layer 60 .

[0092] During the preparation process, the quality and thickness of the p-type cladding layer 70 are guaranteed by controlling growth parameters (such as temperature, time, etc.).

[0093] The p-type cladding layer 70 may include one of p-type gallium arsenide (GaAs), p-type gallium nitride (GaN), or p-type aluminum gallium nitride (AlGaN). Of course, the p-type individual confinement layer 30 may also include other structures.

[0094] It should be emphasized that the materials of the n-type cladding layer 50 and the p-type cladding layer 70 may or may not correspond to each other. The thickness and quality of the p-type cladding layer 70 can be controlled by growth parameters to ensure good lattice matching and electrical performance with the other structural layers.

[0095] After the preparation in step S43 is completed, Figure 5 The structure shown in (b).

[0096] Step S5 : growing a p-type electrode 80 on the p-type cladding layer 70 .

[0097] Step S6 : growing an n-type electrode 90 on the GaAs substrate 10 .

[0098] In step S5 and step S6, the p-type electrode 80 and the n-type electrode 90 can be deposited by evaporation or sputtering. The specific materials of the p-type electrode 80 and the n-type electrode 90 can be set accordingly, and the preparation processes of the p-type electrode 80 and the n-type electrode 90 can be the same or different. After the preparation is completed, the following can be obtained: Figure 5 The photonic crystal surface emitting laser 100 is shown in (c).

[0099] In some feasible implementations, the p-type electrode 80 is made of gold or aluminum, and the n-type electrode 90 is made of gold or aluminum. For example, the p-type electrode 80 and the n-type electrode 90 can both be made of gold; or, the p-type electrode 80 and the n-type electrode 90 can both be made of aluminum; or, one of the p-type electrode 80 and the n-type electrode 90 can be made of gold and the other of the p-type electrode 80 and the n-type electrode 90 can be made of aluminum.

[0100] In some feasible implementations, after the p-type electrode 80 and the n-type electrode 90 are prepared, the method for preparing the photonic crystal surface emitting laser 100 may further include step S7 and step S8.

[0101] Step S7 : performing patterning on the p-type electrode 80 and / or the n-type electrode 90 .

[0102] In step S7, a photolithography or etching process can be used to determine the shape and position of the p-type electrode 80 and / or the n-type electrode 90 to form a patterned p-type electrode 80 and / or a patterned n-type electrode 90. In this way, it can be ensured that there is good ohmic contact between the n-type electrode 90 and the GaAs substrate 10, and between the p-type electrode 80 and the p-type cladding layer 70, to achieve effective electrical injection.

[0103] When a photolithography method is used, the photolithography method may be the same as the method for preparing the photonic crystal 41 in step S3. When an etching process is used, the etching depth may be determined by controlling etching parameters.

[0104] It is worth noting that the p-type electrode 80 and the n-type electrode 90 can be patterned simultaneously, or one of the p-type electrode 80 and the n-type electrode 90 can be patterned while the other is not. Whether the p-type electrode 80 and the n-type electrode 90 are patterned can be adaptively adjusted according to usage requirements.

[0105] Step S8: performing annealing treatment.

[0106] Annealing treatment can repair lattice damage, optimize electrical properties, and reduce defect density.

[0107] In some feasible implementations, after the photonic crystal surface emitting laser 100 is prepared, it can be further processed, including cutting and packaging. Appropriate packaging materials and processes are used to protect the photonic crystal surface emitting laser 100 from external environmental influences while ensuring good heat dissipation and optical performance. The photonic crystal surface emitting laser 100 is fully tested, including laser performance testing (such as wavelength, power, mode, etc.) and electrical performance testing (such as resistance, current injection, etc.) to ensure that the device meets design requirements.

[0108] Figure 6 This is a partial schematic diagram of the light output path of a photonic crystal surface emitting laser provided in an embodiment of the present application.

[0109] See also Figure 6 As shown, the light emission direction of the photonic crystal surface emitting laser 100 of the embodiment of the present application is emitted from the GaAs substrate 10 toward the photonic crystal 41. Among them, the light emission path of the position covered by the photonic crystal 41 is along the path a11, and the light is emitted in a straight line. For the position not covered by the photonic crystal 41, the light emission paths converge toward the position of the photonic crystal 41 along the paths a21 and a31, and after passing through the photonic crystal 41, the light is emitted in the directions a22 and a32, respectively.

[0110] It is worth noting that the light output path can be achieved by adjusting the width d of the photonic crystal 41. For example, when the width dimension of the photonic crystal 41 is relatively small, the light output path may include a11. When the width dimension of the photonic crystal 41 is relatively large, the light output path may include a11, a22 and a32. Similarly, the light output direction can also be achieved by adjusting the positional relationship of the photonic crystal 41. For example, when multiple photonic crystals 41 are arranged in parallel, the light output path a22 in each photonic crystal 41 has the same direction, and the light output path a32 in each photonic crystal 41 has the same direction. For example, when multiple photonic crystals 41 are not arranged in parallel, the directions of the light output paths a22 in two non-parallel photonic crystals 41 are different, and the directions of the light output paths a32 are also different. In this way, the preparation method of the photonic crystal surface emitting laser 100 provided in the embodiment of the present application can adjust the light output direction by the structural size and positional relationship of the photonic crystal 41 to meet the light output requirements of different photonic crystal surface emitting lasers 100.

[0111] In the method for preparing the photonic crystal surface emitting laser 100 provided in the embodiment of the present application, a method for preparing the photonic crystal 41 using a coupling mechanism different from the etching "pore" method is provided. + / n+ A plurality of photonic crystals 41 are formed in the form of a tunnel junction 40, and an n-type cladding layer 50 is used to cover the photonic crystal 41 to form a micro-current injection zone, thereby obtaining a semiconductor heterostructure laser. The plurality of photonic crystals 41 in this preparation method can be arranged in different ways to form a pattern that can realize the desired light-emitting mode, and can realize light emission in all directions to meet the requirements of the different light-emitting characteristics of the photonic crystal surface emitting laser 100, so that light waves interact with each other in the photonic crystals 41 with different arrangements to produce lasers with different characteristics, so as to realize beam shaping, beam steering, high-power short pulse generation and other functions, and improve conversion efficiency. Moreover, this preparation method utilizes the refractive index and gain distribution formed by the tiny current injection zone formed by etching the covering tunneling interface to couple light waves in all directions, which can solve a series of problems related to refractive index coupling, suppress the dual-mode output caused by the AR coating, realize single-mode output, improve the performance of the threshold gain difference between modes, significantly improve the yield problem caused by phase uncertainty, and obtain lower feedback sensitivity.

[0112] Corresponding to the embodiment of the method for preparing the photonic crystal surface emitting laser 100, the present application also provides an embodiment of the photonic crystal surface emitting laser 100. The photonic crystal surface emitting laser 100 is prepared by the method for preparing the photonic crystal surface emitting laser 100 provided in the above embodiment.

[0113] Continue to see Figure 5 As shown in (c), the photonic crystal surface emitting laser 100 adopted in the embodiment of the present application includes a GaAs substrate 10, an n-type doped layer 20, a p-type separate confinement layer 30, a plurality of photonic crystals 41, an n-type cladding layer 50, an undoped active layer 60 and a p-type cladding layer 70, a p-type electrode 80 and an n-type electrode 90.

[0114] The n-type doping layer 20 is provided on the GaAs substrate 10 , and the n-type doping layer 20 can be prepared by step S12 provided in the above embodiment.

[0115] The p-type individual confinement layer 30 is provided on the n-type doping layer 20 . The p-type individual confinement layer 30 can be prepared by step S13 provided in the above embodiment.

[0116] The photonic crystal 41 is arranged in the p-type individual confinement layer 30, and a plurality of photonic crystals 41 are arranged in at least two directions. The cross-sectional shape of the photonic crystal 41 is a preset pattern. The photonic crystal 41 can be formed by the p-type individual confinement layer 30. + / n + The tunnel junction 40 is obtained by etching, and the photonic crystal 41 can be prepared by steps S2 and S3 provided in the above embodiment, wherein a plurality of photonic crystals 41 are in the same plane.

[0117] The n-type cladding layer 50 is provided on the photonic crystal 41 . The n-type cladding layer 50 can be prepared by step S41 provided in the above embodiment.

[0118] The undoped active layer 60 is provided on the n-type cladding layer 50 . The undoped active layer 60 can be prepared by step S42 provided in the above embodiment.

[0119] The p-type cladding layer 70 is provided on the undoped active layer 60 . The p-type cladding layer 70 can be prepared by step S43 provided in the above embodiment.

[0120] The p-type electrode 80 is provided on the p-type cladding layer 70 , and the p-type electrode 80 can be prepared by step S5 provided in the above embodiment.

[0121] The n-type electrode 90 is provided on the GaAs substrate 10 , and the n-type electrode 90 can be prepared by step S6 provided in the above embodiment.

[0122] It should be noted that those skilled in the art will readily conceive of other embodiments of the present application after considering the specification and practicing the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of this application and include common knowledge or customary techniques in the art that are not disclosed in this application.

[0123] It will be understood that the present application is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes may be made without departing from the scope thereof, the true scope being indicated by the present application.

Claims

1. A method for preparing a photonic crystal surface emitting laser, characterized in that: include: The n-type doped layer, p-type separate confinement layer and p-type confinement layer are grown on the GaAs substrate in sequence. + / n + Tunnel knot; In the p + / n + A patterned mask structure is prepared for the tunnel junction; the patterned mask structure includes a plurality of preset patterns; Etch the p according to the preset pattern + / n + Tunnel junctions are formed to obtain a plurality of photonic crystals; wherein the plurality of photonic crystals are arranged along at least two directions; sequentially growing an n-type cladding layer, an undoped active layer, and a p-type cladding layer on the photonic crystal; growing a p-type electrode on the p-type cladding layer; An n-type electrode is grown on the GaAs substrate.

2. The method for preparing a photonic crystal surface emitting laser according to claim 1, wherein: The p is etched according to the preset pattern + / n + Tunnel junctions to obtain multiple photonic crystals, including: Etching the p not covered by the preset pattern + / n + Tunnel knot; The patterned mask structure of the preset pattern is removed to obtain a plurality of photonic crystals; wherein the photonic crystals include the preset pattern.

3. The method for preparing a photonic crystal surface emitting laser according to claim 1, wherein: The preset shapes include one or more of a circle, a triangle, a square, an ellipse or a pentagon.

4. The method for preparing a photonic crystal surface emitting laser according to claim 3, wherein: The multiple photonic crystals have the same shape and are arranged in an array.

5. The method for preparing a photonic crystal surface emitting laser according to claim 1, wherein: The width of the photonic crystal is 10nm-200nm; The distance between the centers of any two adjacent photonic crystals is 50 nm to 300 nm.

6. The method for preparing a photonic crystal surface emitting laser according to claim 1, wherein: The p + / n + The thickness of the tunnel junction is greater than or equal to 10 nm.

7. The method for preparing a photonic crystal surface emitting laser according to claim 1, wherein: The preparation method of the photonic crystal surface emitting laser further comprises: The p-type electrode and / or the n-type electrode are patterned.

8. The method for preparing a photonic crystal surface emitting laser according to claim 7, characterized in that: The material of the p-type electrode includes gold or aluminum; the material of the n-type electrode includes gold or aluminum.

9. The method for preparing a photonic crystal surface emitting laser according to claim 1, wherein: The p + / n + The doping level of the tunnel junction is heavily doped greater than or equal to 10 19 cm -3 .

10. A photonic crystal surface emitting laser, characterized in that: The photonic crystal surface emitting laser is prepared by the method for preparing a photonic crystal surface emitting laser according to any one of claims 1 to 9, wherein the photonic crystal surface emitting laser comprises: GaAs substrate; An n-type doping layer and a p-type separate confinement layer are sequentially provided on the GaAs substrate; A plurality of photonic crystals are arranged in the p-type separate confinement layer; wherein the plurality of photonic crystals are arranged in at least two directions, and the cross-sectional shape of the photonic crystal is a preset pattern, and the plurality of photonic crystals are formed by p-type confinement layers grown on the p-type separate confinement layer. + / n + Tunnel junction etching is obtained; An n-type cladding layer, an undoped active layer and a p-type cladding layer are sequentially arranged on a plurality of the photonic crystals; A p-type electrode, disposed on the p-type cladding layer; The n-type electrode is provided on the GaAs substrate.

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