Deep ultraviolet photonic crystal surface emitting laser

Abstract

The invention discloses a deep ultraviolet photonic crystal surface emitting laser, and relates to the technical field of semiconductor photoelectricity. The deep ultraviolet photonic crystal surface emitting laser comprises a substrate layer, an aluminum nitride template layer, a first Bragg reflection layer, an epitaxial structure and a second Bragg reflection layer, the aluminum nitride template layer is arranged between the first Bragg reflection layer and the substrate layer, and the epitaxial structure is arranged between the second Bragg reflection layer and the first Bragg reflection layer; wherein the first Bragg reflection layer comprises a periodically arranged pore type photonic crystal structure, a plurality of first sub-layers and a plurality of second sub-layers, the first sub-layers comprise an Alx1Ga1-x1N material, the second sub-layers comprise an Alx2Ga1-x2N material, 0.3 < = x1 < = 0.4, and 0.45 < = x2 < = 0.55. According to the deep ultraviolet photonic crystal surface emitting laser, the lasing threshold of the deep ultraviolet photonic crystal surface emitting laser is reduced, and the lasing power of the deep ultraviolet photonic crystal surface emitting laser is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor optoelectronic technology, and in particular to a deep ultraviolet photonic crystal surface emitting laser. Background Art

[0002] With the development of technology and practical needs, ultra-low threshold and extremely small size on-chip lasers have become the core components of modern highly integrated photonic chips. Surface-emitting lasers are the smallest and most energy-efficient of all types of lasers, and are the best solution for realizing small on-chip coherent light sources. However, existing surface-emitting lasers have technical problems such as high lasing threshold and low lasing power. Summary of the invention

[0003] The embodiment of the present application provides a deep ultraviolet photonic crystal surface emitting laser, which is used to solve the technical problems of high lasing threshold and low lasing power in the prior art.

[0004] According to a first aspect of an embodiment of the present application, a deep ultraviolet photonic crystal surface emitting laser is provided, comprising:

[0005] A substrate layer, an aluminum nitride template layer, a first Bragg reflection layer, an epitaxial structure, and a second Bragg reflection layer;

[0006] The aluminum nitride template layer is arranged between the first Bragg reflection layer and the substrate layer, and the epitaxial structure is arranged between the second Bragg reflection layer and the first Bragg reflection layer;

[0007] The first Bragg reflection layer includes a periodically arranged pore-type photonic crystal structure, a plurality of first sublayers and a plurality of second sublayers, wherein the first sublayer includes Al x1 Ga 1-x1 N material, the second sublayer includes Al x2 Ga 1-x2 N material, 0.3≤x1≤0.4, 0.45≤x2≤0.55.

[0008] The deep ultraviolet photonic crystal surface emitting laser in this embodiment reduces the lasing threshold of the deep ultraviolet photonic crystal surface emitting laser and improves the lasing power of the deep ultraviolet photonic crystal surface emitting laser through a periodically arranged air hole type photonic crystal structure, a plurality of first sublayers and a plurality of second sublayers consisting of a first Bragg reflection layer.

[0009] In some embodiments, the epitaxial structure includes an N-type cladding layer, a quantum well active layer, an electron blocking layer, and a hole injection layer;

[0010] The N-type cladding layer is arranged between the first Bragg reflection layer and the quantum well active layer, and the electron blocking layer is arranged between the quantum well active layer and the hole injection layer.

[0011] In some embodiments, the N-type cladding layer includes an N-type doped AlGaN material, the Al component content of the N-type cladding layer is 55% to 65%, the thickness of the N-type cladding layer is 800nm ​​to 2000nm, and the doping concentration of the N-type cladding layer is 6×10 18 cm -3 Up to 6×10 19 cm -3 .

[0012] In some embodiments, the quantum well active layer includes a periodic arrangement structure, the periodic arrangement structure includes at least one potential well layer and at least two potential barrier layers, the potential well layer is arranged between two adjacent potential barrier layers, and the period number of the quantum well active layer is 4 to 6;

[0013] Among them, the potential well layer includes Al y Ga 1-y N material, 0.45≤y≤0.6, y>x1, y>x2, the thickness of the potential well layer is 1nm to 3nm;

[0014] The barrier layer includes Al z Ga 1-z N material, 0.55≤z≤0.7, the thickness of the barrier layer is 6nm to 8nm.

[0015] In some embodiments, the electron blocking layer includes a P-type doped AlGaN material, the Al component content of the electron blocking layer is 75% to 80%, the thickness of the electron blocking layer is 1 nm to 2 nm, and the doping concentration of the electron blocking layer is 2×10 18 cm -3 Up to 5×10 18 cm -3 .

[0016] In some embodiments, the hole injection layer includes a P-type doped AlGaN material, the Al component content of the hole injection layer is 60% to 70%, the thickness of the hole injection layer is 30nm to 50nm, and the doping concentration of the hole injection layer is 2×10 18 cm -3 Up to 5×10 18 cm -3 .

[0017] In some embodiments, the period of the air hole type photonic crystal structure is 20 nm to 300 nm, the depth is 200 nm to 1000 nm, and the duty cycle is 0 to 1.

[0018] In some embodiments, a plurality of first sub-layers and a plurality of second sub-layers are alternately stacked along a first direction, wherein the first direction is a direction from the substrate layer to the second Bragg reflection layer.

[0019] In some embodiments, the second Bragg reflective layer includes a plurality of third sub-layers and a plurality of fourth sub-layers, and the plurality of third sub-layers and the plurality of fourth sub-layers are alternately stacked along the first direction;

[0020] The third sublayer includes SiO2 material, and the fourth sublayer includes HfO2 material.

[0021] In some embodiments, the thickness of the first sublayer is 0.25λ / n1, the thickness of the second sublayer is 0.25λ / n2, the thickness of the third sublayer is 0.25λ / n3, and the thickness of the fourth sublayer is 0.25λ / n4;

[0022] Wherein, λ is the central wavelength corresponding to the quantum well active layer, n1 is the average refractive index of the first sublayer, n2 is the average refractive index of the second sublayer, n3 is the average refractive index of the third sublayer, and n4 is the average refractive index of the fourth sublayer. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0024] Figure 1 A schematic diagram of the structure of a deep ultraviolet photonic crystal surface emitting laser provided in an embodiment of the present application;

[0025] Figure 2 A flow chart for preparing a deep ultraviolet photonic crystal surface emitting laser provided in an embodiment of the present application;

[0026] Figure 3 A cross-sectional view of a photonic crystal structure provided in an embodiment of the present application;

[0027] in, Figure 1 The corresponding relationship between the reference numerals and the component names is as follows:

[0028] 100 deep ultraviolet photonic crystal surface emitting laser, 101 substrate layer, 102 aluminum nitride template layer, 103 first Bragg reflection layer, 104 epitaxial structure, 105 second Bragg reflection layer, 106 air hole type photonic crystal structure, 107 first sublayer, 108 second sublayer, 109 N-type cladding layer, 110 quantum well active layer, 111 electron blocking layer, 112 hole injection layer, 113 potential well layer, 114 potential barrier layer, 115 third sublayer, 116 fourth sublayer. DETAILED DESCRIPTION

[0029] In order to better understand the technical solutions provided by the embodiments of this specification, the technical solutions of the embodiments of this specification are described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of this specification and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of this specification, rather than limitations on the technical solutions of this specification. In the absence of conflict, the embodiments of this specification and the technical features in the embodiments can be combined with each other.

[0030] In this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements limited by the statement "comprise one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. The term "more than two" includes two or more than two situations.

[0031] In some embodiments, Figure 1 The schematic diagram of the structure of the deep ultraviolet photonic crystal surface emitting laser 100 provided in the embodiment of the present application is as follows: Figure 1 As shown, in an embodiment of the present application, a deep ultraviolet photonic crystal surface emitting laser 100 is provided, comprising:

[0032] A substrate layer 101, an aluminum nitride template layer 102, a first Bragg reflection layer 103, an epitaxial structure 104, and a second Bragg reflection layer 105; the aluminum nitride template layer 102 is disposed between the first Bragg reflection layer 103 and the substrate layer 101, and the epitaxial structure 104 is disposed between the second Bragg reflection layer 105 and the first Bragg reflection layer 103; wherein the first Bragg reflection layer 103 includes a periodically arranged pore-type photonic crystal structure 106, a plurality of first sublayers 107, and a plurality of second sublayers 108, and the first sublayer 107 includes Al x1 Ga 1-x1 N material, the second sub-layer 108 includes Al x2 Ga 1-x2 N material, 0.3≤x1≤0.4, 0.45≤x2≤0.55.

[0033] In this embodiment, a deep ultraviolet photonic crystal surface emitting laser 100 is proposed. The deep ultraviolet photonic crystal surface emitting laser 100 includes a substrate layer 101 , an aluminum nitride template layer 102 , a first Bragg reflection layer 103 , an epitaxial structure 104 and a second Bragg reflection layer 105 .

[0034] Exemplarily, the substrate layer 101 can be a substrate for an epitaxial surface emitting laser, the aluminum nitride template layer 102 is a template layer of AlN material, the epitaxial structure 104 is a component structure extending outward from the deep ultraviolet photonic crystal surface emitting laser 100, the first Bragg reflection layer 103 and the second Bragg reflection layer 105 are optical structures capable of reflecting light, and the materials of the first Bragg reflection layer 103 and the second Bragg reflection layer 105 are different.

[0035] The aluminum nitride template layer 102 is disposed between the first Bragg reflective layer 103 and the substrate layer 101 , and the epitaxial structure 104 is disposed between the second Bragg reflective layer 105 and the first Bragg reflective layer 103 .

[0036] Exemplarily, the substrate layer 101 , the aluminum nitride template layer 102 , the first Bragg reflection layer 103 , the epitaxial structure 104 , and the second Bragg reflection layer 105 are stacked in sequence along one direction.

[0037] The first Bragg reflective layer 103 includes a periodically arranged pore-type photonic crystal structure 106 , a plurality of first sublayers 107 , and a plurality of second sublayers 108 , wherein the first sublayer 107 and the second sublayer 108 are structural sublayers in the first Bragg reflective layer 103 .

[0038] Exemplarily, multiple first sublayers 107 and multiple second sublayers 108 are alternately stacked to form a first reflective layer structure, and the periodically arranged pore-type photonic crystal structure 106 is used as a second reflective layer structure. The second reflective layer structure is arranged above the first reflective layer structure to obtain a first Bragg reflective layer 103.

[0039] The first sub-layer 107 includes Al x1 Ga 1-x1 N material, the second sub-layer 108 includes Al x2 Ga 1-x2 N material, where 0.3≤x1≤0.4, 0.45≤x2≤0.55.

[0040] For example, the material of the first sub-layer 107 is unintentionally doped Al x1 Ga 1-x1 N material.

[0041] For example, the material of the second sub-layer 108 is unintentionally doped Al x2 Ga1-x2 N material.

[0042] It should be noted that, in the first Bragg reflection layer 103, a plurality of first sublayers 107 and a plurality of second sublayers 108 are alternately stacked, and a periodically arranged pore-type photonic crystal structure 106 is arranged in the first Bragg reflection layer 103, which can produce a photon bandgap effect, thereby reducing the leakage of light in the optical path of the resonant cavity. The reflectivity of the deep ultraviolet photonic crystal surface emitting laser 100 can be improved through the above-mentioned first Bragg reflection layer 103, and stronger light confinement in the resonant cavity can be achieved, thereby reducing the lasing threshold of the deep ultraviolet photonic crystal surface emitting laser 100 and improving the lasing power of the deep ultraviolet photonic crystal surface emitting laser 100.

[0043] The deep ultraviolet photonic crystal surface emitting laser 100 in this embodiment reduces the lasing threshold of the deep ultraviolet photonic crystal surface emitting laser 100 and improves the lasing power of the deep ultraviolet photonic crystal surface emitting laser 100 through the first Bragg reflection layer 103 composed of a periodically arranged pore-type photonic crystal structure 106, multiple first sublayers 107 and multiple second sublayers 108.

[0044] In some embodiments, a deep ultraviolet photonic crystal surface emitting laser 100 is provided in an embodiment of the present application, and the epitaxial structure 104 includes an N-type cladding layer 109, a quantum well active layer 110, an electron blocking layer 111 and a hole injection layer 112; wherein the N-type cladding layer 109 is arranged between the first Bragg reflection layer 103 and the quantum well active layer 110, and the electron blocking layer 111 is arranged between the quantum well active layer 110 and the hole injection layer 112.

[0045] In this embodiment, the epitaxial structure 104 includes an N-type cladding layer 109 , a quantum well active layer 110 , an electron blocking layer 111 and a hole injection layer 112 , wherein the N-type cladding layer 109 , the quantum well active layer 110 , the electron blocking layer 111 and the hole injection layer 112 are components of the epitaxial structure 104 .

[0046] The N-type cladding layer 109 is disposed between the first Bragg reflective layer 103 and the quantum well active layer 110 , the electron blocking layer 111 is disposed between the quantum well active layer 110 and the hole injection layer 112 , and the hole injection layer 112 is disposed between the electron blocking layer 111 and the second Bragg reflective layer 105 .

[0047] Exemplarily, the N-type cladding layer 109 , the quantum well active layer 110 , the electron blocking layer 111 and the hole injection layer 112 are stacked in sequence along one direction to form the epitaxial structure 104 .

[0048] In some embodiments, a deep ultraviolet photonic crystal surface emitting laser 100 is provided in an embodiment of the present application, wherein the N-type cladding layer 109 comprises an N-type doped AlGaN material, the Al component content of the N-type cladding layer 109 is 55% to 65%, the thickness of the N-type cladding layer 109 is 800nm ​​to 2000nm, and the doping concentration of the N-type cladding layer 109 is 6×10 18 cm -3 Up to 6×10 19 cm -3 .

[0049] In this embodiment, the N-type cladding layer 109 includes N-type doped AlGaN material.

[0050] Exemplarily, the N-type cladding layer 109 may be a cladding layer made of N-type doped AlGaN material.

[0051] The Al component content of the N-type cladding layer 109 is 55% to 65%, the thickness of the N-type cladding layer 109 is 800nm ​​to 2000nm, and the doping concentration of the N-type cladding layer 109 is 6×10 18 cm -3 Up to 6×10 19 cm -3 .

[0052] In some embodiments, a deep ultraviolet photonic crystal surface emitting laser 100 is provided in an embodiment of the present application, wherein the quantum well active layer 110 comprises a periodic arrangement structure, wherein the periodic arrangement structure comprises at least one potential well layer 113 and at least two potential barrier layers 114, wherein the potential well layer 113 is disposed between two adjacent potential barrier layers 114, and the period number of the quantum well active layer 110 is 4 to 6; wherein the potential well layer 113 comprises Al y Ga 1-y N material, 0.45≤y≤0.6, y>x1, y>x2, the thickness of the potential well layer 113 is 1nm to 3nm; the barrier layer 114 includes Al z Ga 1-z N material, 0.55≤z≤0.7, the thickness of the barrier layer 114 is 6nm to 8nm.

[0053] In this embodiment, the quantum well active layer 110 includes a periodic arrangement structure, and the periodic arrangement structure includes at least one potential well layer 113 and at least two potential barrier layers 114 .

[0054] At least one potential well layer 113 and at least two potential barrier layers 114 are stacked, and each potential well layer 113 is disposed between two adjacent potential barrier layers 114 .

[0055] The number of periods of the quantum well active layer 110 is 4 to 6.

[0056] Exemplarily, when the period number of the quantum well active layer 110 is 4, the quantum well active layer 110 includes 4 potential well layers 113 and 5 potential barrier layers 114 .

[0057] Exemplarily, when the period number of the quantum well active layer 110 is 6, the quantum well active layer 110 includes 6 potential well layers 113 and 7 potential barrier layers 114 .

[0058] The potential well layer 113 includes Al y Ga 1-y N material, 0.45≤y≤0.6, y>x1, y>x2, the thickness of the potential well layer 113 is 1nm to 3nm. In addition, the barrier layer 114 includes Al z Ga 1-z N material, 0.55≤z≤0.7, the thickness of the barrier layer 114 is 6nm to 8nm.

[0059] In some embodiments, a deep ultraviolet photonic crystal surface emitting laser 100 is provided in an embodiment of the present application, wherein the electron blocking layer 111 comprises a P-type doped AlGaN material, the Al component content of the electron blocking layer 111 is 75% to 80%, the thickness of the electron blocking layer 111 is 1 nm to 2 nm, and the doping concentration of the electron blocking layer 111 is 2×10 18 cm -3 Up to 5×10 18 cm -3 .

[0060] In this embodiment, the electron blocking layer 111 includes a P-type doped AlGaN material.

[0061] Exemplarily, the electron blocking layer 111 is made of P-type doped AlGaN material.

[0062] The Al component content of the electron blocking layer 111 is 75% to 80%, the thickness of the electron blocking layer 111 is 1 nm to 2 nm, and the doping concentration of the electron blocking layer 111 is 2×10 18 cm -3 Up to 5×10 18 cm -3 .

[0063] In some embodiments, a deep ultraviolet photonic crystal surface emitting laser 100 is provided in an embodiment of the present application, wherein the hole injection layer 112 comprises a P-type doped AlGaN material, the Al component content of the hole injection layer 112 is 60% to 70%, the thickness of the hole injection layer 112 is 30nm to 50nm, and the doping concentration of the hole injection layer 112 is 2×10 18 cm -3 Up to 5×10 18 cm-3 .

[0064] In this embodiment, the hole injection layer 112 includes a P-type doped AlGaN material.

[0065] Exemplarily, the hole injection layer 112 is prepared by using a P-type doped AlGaN material.

[0066] In some embodiments, a deep ultraviolet photonic crystal surface emitting laser 100 is provided in the embodiments of the present application, and the period of the air hole type photonic crystal structure 106 is 20nm to 300nm, the depth is 200nm to 1000nm, and the duty cycle is 0 to 1.

[0067] In this embodiment, the period of the air hole type photonic crystal structure 106 is 20 nm to 300 nm, the depth is 200 nm to 1000 nm, and the duty cycle is 0 to 1.

[0068] Exemplarily, the pore type photonic crystal structure 106 includes a plurality of periodically arranged pores, wherein the plurality of pores are arranged laterally, the period of the plurality of pores is 20nm to 300nm, the depth of the pores is 200nm to 1000nm, and the pore duty ratio in the pore type photonic crystal structure 106 is 0 to 1.

[0069] In some embodiments, a deep ultraviolet photonic crystal surface emitting laser 100 is provided in an embodiment of the present application, wherein a plurality of first sublayers 107 and a plurality of second sublayers 108 are alternately stacked along a first direction, wherein the first direction is the direction from the substrate layer 101 to the second Bragg reflection layer 105 .

[0070] In this embodiment, the direction from the substrate layer 101 to the second Bragg reflective layer 105 is determined as a first direction, wherein a plurality of first sub-layers 107 and a plurality of second sub-layers 108 are alternately stacked along the first direction.

[0071] Exemplarily, the number of first sub-layers 107 in the first Bragg reflective layer 103 ranges from 20 to 50.

[0072] Exemplarily, the number of the second sub-layers 108 in the first Bragg reflective layer 103 ranges from 20 to 50.

[0073] Exemplarily, a plurality of first sublayers 107 and a plurality of second sublayers 108 are alternately stacked along a first direction, and a pore-type photonic crystal structure 106 is disposed above the plurality of first sublayers 107 and the plurality of second sublayers 108 to form a first Bragg reflection layer 103 .

[0074] In some embodiments, a deep ultraviolet photonic crystal surface emitting laser 100 is provided in an embodiment of the present application, and the second Bragg reflection layer 105 includes a plurality of third sublayers 115 and a plurality of fourth sublayers 116, and the plurality of third sublayers 115 and the plurality of fourth sublayers 116 are alternately stacked along a first direction; wherein the third sublayer 115 includes SiO2 material, and the fourth sublayer 116 includes HfO2 material.

[0075] In this embodiment, the second Bragg reflection layer 105 includes a plurality of third sub-layers 115 and a plurality of fourth sub-layers 116, which are alternately stacked along a first direction, wherein the third sub-layer 115 includes SiO2 material, and the fourth sub-layer 116 includes HfO2 material.

[0076] Exemplarily, the number of the third sub-layers 115 in the second Bragg reflective layer 105 ranges from 20 to 50.

[0077] Exemplarily, the number of the fourth sublayer 116 in the second Bragg reflective layer 105 ranges from 20 to 50.

[0078] In some embodiments, a deep ultraviolet photonic crystal surface emitting laser 100 is provided in an embodiment of the present application, wherein the thickness of the first sublayer 107 is 0.25λ / n1, the thickness of the second sublayer 108 is 0.25λ / n2, the thickness of the third sublayer 115 is 0.25λ / n3, and the thickness of the fourth sublayer 116 is 0.25λ / n4; wherein λ is the central wavelength corresponding to the quantum well active layer 110, n1 is the average refractive index of the first sublayer 107, n2 is the average refractive index of the second sublayer 108, n3 is the average refractive index of the third sublayer 115, and n4 is the average refractive index of the fourth sublayer 116.

[0079] In this embodiment, the thickness of the first sublayer 107 is defined as 0.25λ / n1, the thickness of the second sublayer 108 is defined as 0.25λ / n2, the thickness of the third sublayer 115 is defined as 0.25λ / n3, and the thickness of the fourth sublayer 116 is defined as 0.25λ / n4.

[0080] Among them, λ is the central wavelength corresponding to the quantum well active layer 110 , n1 is the average refractive index of the first sublayer 107 , n2 is the average refractive index of the second sublayer 108 , n3 is the average refractive index of the third sublayer 115 , and n4 is the average refractive index of the fourth sublayer 116 .

[0081] Exemplarily, λ is the central wavelength of light emitted from the quantum well active layer 110 .

[0082] For example, Figure 2 The preparation flow chart of the deep ultraviolet photonic crystal surface emitting laser 100 provided in the embodiment of the present application is as follows: Figure 2 As shown, a photonic crystal structure is formed in the first Bragg reflection layer 103 by using nano-ball etching technology, and the specific operation steps are as follows:

[0083] S1, epitaxially growing an AIN template layer and a first Bragg reflection layer on a substrate;

[0084] S2, depositing SiO2 on the first Bragg reflection layer;

[0085] S3, preparing a nanosphere self-assembly mask and transferring it to the surface of the epitaxial wafer;

[0086] S4, dry etching SiO2 and removing the nanosphere mask;

[0087] S5, dry etching the first Bragg reflective layer and removing the SiO2 mask;

[0088] S6, continue to epitaxially grow other epitaxial structures.

[0089] In this embodiment, first, SiO 2 with a thickness of about 100 nm is deposited on the first Bragg reflective layer as a hard mask for subsequent etching.

[0090] Next, prepare the nanosphere self-assembly mask as follows:

[0091] A polystyrene (PS) nanosphere solution with a concentration of 5 wt.% was diluted with anhydrous ethanol.

[0092] Specifically, when the diameter of the PS nanosphere is 300 nm, the dilution ratio is: PS nanosphere solution: anhydrous ethanol = 1:4.

[0093] For example, the diameter of the nanosphere can be selected according to the required period of the photonic crystal, and the dilution ratio also needs to be adjusted according to the diameter of the nanosphere.

[0094] Afterwards, put an appropriate amount of deionized water in the culture dish, and insert a glass slide obliquely into the culture dish so that it is partially immersed in the water surface; then, add an appropriate amount of diluted PS ball solution drop by drop along the obliquely inserted glass slide onto the water surface. Due to the effect of surface tension, the nanospheres on the air-water interface will self-assemble to form a layer of tightly arranged nanosphere film.

[0095] Finally, the completed epitaxial wafer is placed underwater and pulled upward to transfer the nanosphere film on the water surface to the surface of the epitaxial wafer, and then naturally air-dried to ensure that the nanosphere film is firmly attached to the epitaxial wafer.

[0096] In some embodiments, after the epitaxial wafer is completely dried, it can be treated with O2 plasma to reduce the diameter of the nanospheres to prepare photonic crystals with different duty cycles.

[0097] After preparing the nanosphere self-assembly mask, the pattern was transferred to the SiO2 hard mask using an inductively coupled plasma (ICP) etching system with a CHF3 / Ar mixture as the etching gas, and then the nanosphere self-assembly mask was removed ultrasonically using toluene.

[0098] Afterwards, the DBR is etched using an ICP etching system with a BCl3 / Cl2 mixed gas as the etching gas and SiO2 as a hard mask, and the etching depth must be deep enough (greater than 200nm) so that the pores in the subsequent epitaxial growth process will not be completely filled to form the desired photonic crystal structure.

[0099] Finally, the SiO2 template was removed using a buffered oxide etchant (BOE), and the epitaxial wafer was cleaned in sequence using acetone, isopropanol, and deionized water to complete the preparation of the photonic crystal. Figure 3 The cross-sectional view of the photonic crystal structure provided in the embodiment of the present application is shown in FIG. Figure 3 As shown, where q is the air hole in the photonic crystal.

[0100] It should be noted that in the above embodiments, the description of each embodiment has its own emphasis, and for parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0101] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

[0102] Although the preferred embodiments of this specification have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of this specification.

[0103] Obviously, those skilled in the art can make various changes and modifications to this specification without departing from the spirit and scope of this specification. Thus, if these modifications and variations of this specification fall within the scope of the claims of this specification and their equivalents, this specification is also intended to include these modifications and variations.

Claims

1. A deep ultraviolet photonic crystal surface emitting laser, characterized in that: include: A substrate layer, an aluminum nitride template layer, a first Bragg reflection layer, an epitaxial structure, and a second Bragg reflection layer; The aluminum nitride template layer is disposed between the first Bragg reflection layer and the substrate layer, and the epitaxial structure is disposed between the second Bragg reflection layer and the first Bragg reflection layer; The first Bragg reflection layer includes a periodically arranged pore-type photonic crystal structure, a plurality of first sublayers and a plurality of second sublayers, wherein the first sublayer includes Al x1 Ga 1-x1 N material, the second sublayer includes Al x2 Ga 1-x2 N material, 0.3≤x1≤0.4, 0.45≤x2≤0.

55.

2. The deep ultraviolet photonic crystal surface emitting laser according to claim 1, characterized in that: The epitaxial structure includes an N-type cladding layer, a quantum well active layer, an electron blocking layer and a hole injection layer; The N-type cladding layer is disposed between the first Bragg reflection layer and the quantum well active layer, and the electron blocking layer is disposed between the quantum well active layer and the hole injection layer.

3. The deep ultraviolet photonic crystal surface emitting laser according to claim 2, characterized in that: The N-type cladding layer comprises an N-type doped AlGaN material, the Al component content of the N-type cladding layer is 55% to 65%, the thickness of the N-type cladding layer is 800nm ​​to 2000nm, and the doping concentration of the N-type cladding layer is 6×10 18 cm -3 Up to 6×10 19 cm -3 .

4. The deep ultraviolet photonic crystal surface emitting laser according to claim 2, characterized in that: The quantum well active layer comprises a periodic arrangement structure, the periodic arrangement structure comprises at least one potential well layer and at least two potential barrier layers, the potential well layer is arranged between two adjacent potential barrier layers, and the period number of the quantum well active layer is 4 to 6; Wherein, the potential well layer includes Al y Ga 1-y N material, 0.45≤y≤0.6, y>x1, y>x2, the thickness of the potential well layer is 1nm to 3nm; The barrier layer includes Al z Ga 1-z N material, 0.55≤z≤0.7, and the thickness of the barrier layer is 6nm to 8nm.

5. The deep ultraviolet photonic crystal surface emitting laser according to claim 2, characterized in that: The electron blocking layer comprises a P-type doped AlGaN material, the Al component content of the electron blocking layer is 75% to 80%, the thickness of the electron blocking layer is 1nm to 2nm, and the doping concentration of the electron blocking layer is 2×10 18 cm -3 Up to 5×10 18 cm -3 .

6. The deep ultraviolet photonic crystal surface emitting laser according to claim 2, characterized in that: The hole injection layer comprises a P-type doped AlGaN material, the Al component content of the hole injection layer is 60% to 70%, the thickness of the hole injection layer is 30nm to 50nm, and the doping concentration of the hole injection layer is 2×10 18 cm -3 Up to 5×10 18 cm -3 .

7. The deep ultraviolet photonic crystal surface emitting laser according to any one of claims 1 to 6, characterized in that: The period of the pore-type photonic crystal structure is 20nm to 300nm, the depth is 200nm to 1000nm, and the duty cycle is 0 to 1.

8. The deep ultraviolet photonic crystal surface emitting laser according to any one of claims 1 to 6, characterized in that: A plurality of the first sub-layers and a plurality of the second sub-layers are alternately stacked along a first direction, wherein the first direction is a direction from the substrate layer to the second Bragg reflection layer.

9. The deep ultraviolet photonic crystal surface emitting laser according to claim 8, characterized in that: The second Bragg reflection layer includes a plurality of third sub-layers and a plurality of fourth sub-layers, and the plurality of third sub-layers and the plurality of fourth sub-layers are alternately stacked along the first direction; Wherein, the third sub-layer includes SiO2 material, and the fourth sub-layer includes HfO2 material.

10. The deep ultraviolet photonic crystal surface emitting laser according to claim 9, characterized in that: The thickness of the first sublayer is 0.25λ / n1, the thickness of the second sublayer is 0.25λ / n2, the thickness of the third sublayer is 0.25λ / n3, and the thickness of the fourth sublayer is 0.25λ / n4; Among them, λ is the central wavelength corresponding to the quantum well active layer, n1 is the average refractive index of the first sublayer, n2 is the average refractive index of the second sublayer, n3 is the average refractive index of the third sublayer, and n4 is the average refractive index of the fourth sublayer.

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