阅读说明：本技术 基于二维钙钛矿单晶的垂直腔面发射激光器及其制备方法 (Vertical-cavity surface-emitting laser based on two-dimensional perovskite single crystal and preparation method thereof ) 是由 蒋小强 何云 许剑 刘桂芝 于 2020-04-28 设计创作，主要内容包括：本发明提供一种基于二维钙钛矿单晶的垂直腔面发射激光器及其制备方法,利用二维钙钛矿单晶作为垂直腔面发射激光器的光增益材料,二维钙钛矿单晶包括N层二维钙钛矿单层,N≥2；二维钙钛矿单层包括n层共角卤化铅八面体、n-1层有机配体A及2层有机配体B,n≥1,且二维钙钛矿单层均具有相同的n值,有机配体A嵌入共角卤化铅八面体空隙,有机配体B分别位于共角卤化铅八面体的相对两侧,二维钙钛矿单层的化学式为B<Sub>2</Sub>A<Sub>n-1</Sub>Pb<Sub>n</Sub>X<Sub>3n+1</Sub>,X为卤族元素,且有机配体B的碳原子数大于有机配体A；本发明基于二维钙钛矿单晶的垂直腔面发射激光器具有环境稳定性高、发射波长随n值可调、激光阈值低和品质因子高的优点。(The invention provides a vertical-cavity surface-emitting laser based on two-dimensional perovskite single crystal and a preparation method thereof, wherein the two-dimensional perovskite single crystal is used as an optical gain material of the vertical-cavity surface-emitting laser, the two-dimensional perovskite single crystal comprises N layers of two-dimensional perovskite single layers, and N is more than or equal to 2; the two-dimensional perovskite single layer comprises n layers of common-angle lead halide octahedrons, n-1 layers of organic ligands A and 2 layers of organic ligands B, wherein n is more than or equal to 1, the two-dimensional perovskite single layers have the same n value, the organic ligands A are embedded into the gaps of the common-angle lead halide octahedrons, the organic ligands B are respectively positioned at two opposite sides of the common-angle lead halide octahedrons, and the chemical formula of the two-dimensional perovskite single layer is B 2 A n‑1 Pb n X 3n+1 X is a halogen element, and the carbon atom number of the organic ligand B is greater than that of the organic ligand A; the vertical-cavity surface-emitting laser based on the two-dimensional perovskite single crystal has the advantages of high environmental stability, adjustable emission wavelength along with n value, low laser threshold and qualityThe factor is high.)

1. A vertical cavity surface emitting laser based on a two-dimensional perovskite single crystal is characterized in that: the vertical cavity surface emitting laser comprises a substrate, a first reflector, a two-dimensional perovskite single crystal and a second reflector; wherein the two-dimensional perovskite single crystal comprises N two-dimensional perovskite single layers, and N is more than or equal to 2; the two-dimensional perovskite single layer comprises n layers of common-angle lead halide octahedrons, n-1 layers of organic ligands A and 2 layers of organic ligands B, n is more than or equal to 1, and the two-dimensional perovskiteThe monolayers have the same n value, the organic ligands A are embedded into the common angle lead halide octahedron gaps, the organic ligands B are respectively positioned at two opposite sides of the common angle lead halide octahedron, and the chemical formula of the two-dimensional perovskite monolayer is B₂A_n-1Pb_nX_3n+1And X is a halogen element, and the number of carbon atoms of the organic ligand B is greater than that of the organic ligand A.

2. The vertical-cavity surface-emitting laser based on a two-dimensional perovskite single crystal according to claim 1, characterized in that: the vertical-cavity surface-emitting laser further comprises a first adjusting layer located between the first reflector and the two-dimensional perovskite single crystal and a second adjusting layer located between the two-dimensional perovskite single crystal and the second reflector, and the optical thicknesses of the first adjusting layer and the second adjusting layer are equal.

3. The vertical-cavity surface-emitting laser based on a two-dimensional perovskite single crystal according to claim 2, characterized in that: the optical thickness of the two-dimensional perovskite single crystal is 1/6 of the resonant wavelength of the laser, and the total optical thickness of the first adjusting layer, the two-dimensional perovskite single crystal and the second adjusting layer is 1/2 of the resonant wavelength of the laser; the first adjusting layer includes a silicon dioxide layer, and the second adjusting layer includes a silicon dioxide layer.

4. The vertical-cavity surface-emitting laser based on a two-dimensional perovskite single crystal according to claim 1, characterized in that: the organic ligand A comprises CH₃NH₃ ⁺(ii) a The organic ligand B comprises C₄H₉NH₃ ⁺Or C₈H₉NH₃ ⁺(ii) a The X comprises one of I element, Cl element and Br element.

5. The vertical-cavity surface-emitting laser based on a two-dimensional perovskite single crystal according to claim 1, characterized in that: the value range of N comprises that N is more than or equal to 10; the value range of n is more than or equal to 1 and less than or equal to 5.

6. The vertical-cavity surface-emitting laser based on a two-dimensional perovskite single crystal according to claim 1, characterized in that: the two-dimensional perovskite single crystal has a horizontal plane away from the substrate surface.

7. The vertical-cavity surface-emitting laser based on a two-dimensional perovskite single crystal according to claim 1, characterized in that: the reflectivity of the first reflector is more than 99.5%, and the reflectivity of the second reflector is less than 99%.

8. The vertical-cavity surface-emitting laser based on a two-dimensional perovskite single crystal according to claim 1, characterized in that: the first reflector is a distributed Bragg reflector and comprises a titanium dioxide layer and a silicon dioxide layer which are sequentially overlapped, and the optical thicknesses of the titanium dioxide layer and the silicon dioxide layer are 1/4 of the resonant wavelength of the laser respectively; the second reflector is a distributed Bragg reflector, and comprises a zinc sulfide layer and a magnesium fluoride layer which are sequentially superposed, and the optical thicknesses of the zinc sulfide layer and the magnesium fluoride layer are 1/4 of the resonant wavelength of the laser respectively.

9. A preparation method of a vertical cavity surface emitting laser based on two-dimensional perovskite single crystal is characterized by comprising the following steps:

providing a substrate;

forming a first reflector on the substrate;

forming a two-dimensional perovskite single crystal on the first reflector, wherein the two-dimensional perovskite single crystal comprises N two-dimensional perovskite single layers, and N is more than or equal to 2; the two-dimensional perovskite single layer comprises n layers of common-angle lead halide octahedrons, n-1 layers of organic ligands A and 2 layers of organic ligands B, wherein n is more than or equal to 1, the two-dimensional perovskite single layers have the same n value, the organic ligands A are embedded into the gaps of the common-angle lead halide octahedrons, the organic ligands B are respectively positioned on two opposite sides of the common-angle lead halide octahedrons, and the chemical formula of the two-dimensional perovskite single layer is B₂A_n-1Pb_nX_3n+1X is a halogen element,and the number of carbon atoms of the organic ligand B is greater than that of the organic ligand A;

and forming a second mirror on the two-dimensional perovskite single crystal.

10. The method of claim 9, wherein: the method further comprises a step of forming a first adjusting layer between the first reflecting mirror and the two-dimensional perovskite single crystal by adopting an electron beam thermal evaporation method and a step of forming a second adjusting layer between the two-dimensional perovskite single crystal and the second reflecting mirror by adopting the electron beam thermal evaporation method, and the optical thicknesses of the first adjusting layer and the second adjusting layer are equal.

11. The method of manufacturing according to claim 10, wherein: the optical thickness of the two-dimensional perovskite single crystal is 1/6 of the resonant wavelength of the laser, and the total optical thickness of the first adjusting layer, the two-dimensional perovskite single crystal and the second adjusting layer is 1/2 of the resonant wavelength of the laser; the first adjusting layer includes a silicon dioxide layer, and the second adjusting layer includes a silicon dioxide layer.

12. The method of claim 9, wherein: the organic ligand A comprises CH₃NH₃ ⁺(ii) a The organic ligand B comprises C₄H₉NH₃ ⁺Or C₈H₉NH₃ ⁺(ii) a The X comprises one of I element, Cl element and Br element.

13. The production method according to claim 9, wherein the step of forming the two-dimensional perovskite single crystal on the first mirror includes:

forming a blocky two-dimensional perovskite single crystal by adopting a precursor solution self-assembly crystallization method;

stripping the blocky two-dimensional perovskite single crystal by adopting a mechanical stripping method to obtain a layered two-dimensional perovskite single crystal;

and transferring the layered two-dimensional perovskite single crystal onto the first reflecting mirror by adopting dry transfer.

14. The method of claim 9, wherein: obtaining the two-dimensional perovskite single crystal with N being more than or equal to 10 by adopting an atomic force microscope; the value range of n comprises that n is more than or equal to 1 and less than or equal to 5; the two-dimensional perovskite single crystal is formed to have a horizontal plane away from the substrate surface.

15. The method of claim 9, wherein: the method for forming the first and second mirrors includes an electron beam thermal evaporation method; the reflectivity of the first reflector is more than 99.5%, and the reflectivity of the second reflector is less than 99%.

16. The method of claim 9, wherein: the formed first reflector is a distributed Bragg reflector and comprises a titanium dioxide layer and a silicon dioxide layer which are sequentially overlapped, and the optical thicknesses of the titanium dioxide layer and the silicon dioxide layer are 1/4 of the resonant wavelength of the laser respectively; the second reflector is a distributed Bragg reflector and comprises a zinc sulfide layer and a magnesium fluoride layer which are sequentially stacked, and the optical thicknesses of the zinc sulfide layer and the magnesium fluoride layer are 1/4 of the resonant wavelength of the laser respectively.

Technical Field

The invention belongs to the field of semiconductor optoelectronic devices, and relates to a vertical cavity surface emitting laser based on two-dimensional perovskite single crystal and a preparation method thereof.

Background

Vertical Cavity Surface Emitting lasers (Vertical Cavity Surface Emitting L aser, VCSE L) are different from light Emitting diodes (L ED) and laser diodes (L D), have the advantages of small volume, low threshold value, low price, easy integration into large-area arrays and the like, and are widely applied to the fields of optical communication, optical interconnection, optical storage and the like.

Two-dimensional perovskite has better moisture resistance than three-dimensional perovskite, so that the environmental stability of the two-dimensional perovskite is far higher than that of the three-dimensional perovskite, and the two-dimensional perovskite has the characteristic of quantum well.

At present, L ED based on composite two-dimensional perovskite and a solar cell are successfully developed, but when the composite two-dimensional perovskite thin film prepared based on a spin coating method is applied to a vertical cavity surface emitting laser, the composite two-dimensional perovskite thin film has the defects of not single emission wavelength and a large number of interface defects, and the application of the composite two-dimensional perovskite thin film as a laser material is limited.

Therefore, it is necessary to provide a vertical cavity surface emitting laser based on a two-dimensional perovskite single crystal and a method for manufacturing the same.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present invention aims to provide a vertical cavity surface emitting laser based on a two-dimensional perovskite single crystal and a method for manufacturing the same, which are used to solve the problems of low environmental stability, non-uniform emission wavelength and interface defect of the perovskite vertical cavity surface emitting laser.

In order to achieve the above and other related objects, the present invention provides a vertical cavity surface emitting laser based on a two-dimensional perovskite single crystal, the vertical cavity surface emitting laser including a substrate, a first reflecting mirror, a two-dimensional perovskite single crystal, and a second reflecting mirror; wherein the two-dimensional perovskite single crystal comprises N two-dimensional perovskite single layers, and N is more than or equal to 2; the two-dimensional perovskite monolayer comprises n layers of common-angle lead halide octahedra, n-1 layers of organic ligand A and 2 layersThe organic ligand B is not less than 1, the two-dimensional perovskite single layers have the same n value, the organic ligand A is embedded into the co-angle lead halide octahedron gap, the organic ligand B is respectively positioned at two opposite sides of the co-angle lead halide octahedron, and the chemical formula of the two-dimensional perovskite single layer is B₂A_n-1Pb_nX_3n+1And X is a halogen element, and the number of carbon atoms of the organic ligand B is greater than that of the organic ligand A.

Optionally, the vcsel further includes a first adjustment layer located between the first mirror and the two-dimensional perovskite single crystal and a second adjustment layer located between the two-dimensional perovskite single crystal and the second mirror, and optical thicknesses of the first adjustment layer and the second adjustment layer are equal.

Optionally, the optical thickness of the two-dimensional perovskite single crystal is 1/6 of the laser resonance wavelength, and the total optical thickness of the first adjustment layer, the two-dimensional perovskite single crystal and the second adjustment layer is 1/2 of the laser resonance wavelength; the first adjusting layer includes a silicon dioxide layer, and the second adjusting layer includes a silicon dioxide layer.

Optionally, the organic ligand A comprises CH₃NH₃ ⁺(ii) a The organic ligand B comprises C₄H₉NH₃ ⁺Or C₈H₉NH₃ ⁺(ii) a The X comprises one of I element, Cl element and Br element.

Optionally, the value range of N includes N ≥ 10; the value range of n is more than or equal to 1 and less than or equal to 5.

Optionally, the two-dimensional perovskite single crystal has a horizontal plane away from the substrate surface.

Optionally, the reflectivity of the first mirror is greater than 99.5% and the reflectivity of the second mirror is less than 99%.

Optionally, the first mirror is a distributed bragg mirror, and includes a titanium dioxide layer and a silicon dioxide layer that are sequentially stacked, and optical thicknesses of the titanium dioxide layer and the silicon dioxide layer are 1/4 of the laser resonant wavelength respectively; the second reflector is a distributed Bragg reflector, and comprises a zinc sulfide layer and a magnesium fluoride layer which are sequentially superposed, and the optical thicknesses of the zinc sulfide layer and the magnesium fluoride layer are 1/4 of the resonant wavelength of the laser respectively.

The invention also provides a preparation method of the vertical cavity surface emitting laser based on the two-dimensional perovskite single crystal, which comprises the following steps:

providing a substrate;

forming a first reflector on the substrate;

forming a two-dimensional perovskite single crystal on the first reflector, wherein the two-dimensional perovskite single crystal comprises N two-dimensional perovskite single layers, and N is more than or equal to 2; the two-dimensional perovskite single layer comprises n layers of common-angle lead halide octahedrons, n-1 layers of organic ligands A and 2 layers of organic ligands B, wherein n is more than or equal to 1, the two-dimensional perovskite single layers have the same n value, the organic ligands A are embedded into the gaps of the common-angle lead halide octahedrons, the organic ligands B are respectively positioned on two opposite sides of the common-angle lead halide octahedrons, and the chemical formula of the two-dimensional perovskite single layer is B₂A_n-1Pb_nX_3n+1X is a halogen element, and the number of carbon atoms of the organic ligand B is greater than that of the organic ligand A;

and forming a second mirror on the two-dimensional perovskite single crystal.

Optionally, the method further comprises a step of forming a first adjusting layer between the first reflecting mirror and the two-dimensional perovskite single crystal by using an electron beam thermal evaporation method and a step of forming a second adjusting layer between the two-dimensional perovskite single crystal and the second reflecting mirror by using an electron beam thermal evaporation method, and the optical thicknesses of the first adjusting layer and the second adjusting layer are equal.

Optionally, the optical thickness of the two-dimensional perovskite single crystal is 1/6 of the laser resonance wavelength, and the total optical thickness of the first adjustment layer, the two-dimensional perovskite single crystal and the second adjustment layer is 1/2 of the laser resonance wavelength; the first adjusting layer includes a silicon dioxide layer, and the second adjusting layer includes a silicon dioxide layer.

Optionally, the organic ligand A comprises CH₃NH₃ ⁺(ii) a The organic ligand B comprises C₄H₉NH₃ ⁺Or C₈H₉NH₃ ⁺(ii) a The X comprises one of I element, Cl element and Br element.

Optionally, the step of forming the two-dimensional perovskite single crystal on the first mirror includes:

forming a blocky two-dimensional perovskite single crystal by adopting a precursor solution self-assembly crystallization method;

stripping the blocky two-dimensional perovskite single crystal by adopting a mechanical stripping method to obtain a layered two-dimensional perovskite single crystal;

and transferring the layered two-dimensional perovskite single crystal onto the first reflecting mirror by adopting dry transfer.

Optionally, obtaining the two-dimensional perovskite single crystal with N being more than or equal to 10 by adopting an atomic force microscope; the value range of n comprises that n is more than or equal to 1 and less than or equal to 5; the two-dimensional perovskite single crystal is formed to have a horizontal plane away from the substrate surface.

Optionally, the method of forming the first and second mirrors includes an electron beam thermal evaporation method; the reflectivity of the first reflector is more than 99.5%, and the reflectivity of the second reflector is less than 99%.

Optionally, the first mirror is a distributed bragg mirror, and includes a titanium dioxide layer and a silicon dioxide layer that are sequentially stacked, and optical thicknesses of the titanium dioxide layer and the silicon dioxide layer are 1/4 of the laser resonant wavelength respectively; the second reflector is a distributed Bragg reflector and comprises a zinc sulfide layer and a magnesium fluoride layer which are sequentially stacked, and the optical thicknesses of the zinc sulfide layer and the magnesium fluoride layer are 1/4 of the resonant wavelength of the laser respectively.

As described above, the vertical cavity surface emitting laser based on the two-dimensional perovskite single crystal and the preparation method thereof utilize the two-dimensional perovskite single crystal as the optical gain material of the vertical cavity surface emitting laser, wherein the two-dimensional perovskite single crystal comprises N layers of two-dimensional perovskite single layers, and N is more than or equal to 2; the two-dimensional perovskite single layer comprises n layers of common-angle lead halide octahedrons, n-1 layers of organic ligands A and 2 layers of organic ligands B, wherein n is more than or equal to 1, and the two-dimensional perovskite single layers have the same n value which isThe organic ligand A is embedded into the common-angle lead halide octahedron gap, the organic ligand B is respectively positioned at two opposite sides of the common-angle lead halide octahedron, and the chemical formula of the two-dimensional perovskite single layer is B₂A_n-1Pb_nX_3n+1And X is a halogen element, and the number of carbon atoms of the organic ligand B is greater than that of the organic ligand A. The large-volume organic ligand B in the two-dimensional perovskite single crystal can effectively isolate water molecules, so that the environmental stability of the vertical cavity surface emitting laser is improved; each two-dimensional perovskite single layer in the two-dimensional perovskite single crystal has the same n value, namely the two-dimensional perovskite single layers have the same number of lead halide single layers, so that the emission wavelength of the two-dimensional perovskite single crystal is unique, the emission wavelength can be adjusted along with the change of the n value in the two-dimensional perovskite single layer, and the threshold value of a laser is reduced; the interface defects of the two-dimensional perovskite single crystal are few, and the fluorescence quantum yield is high; the surface of the two-dimensional perovskite single crystal is smooth, so that a high-quality reflector can be grown on the two-dimensional perovskite single crystal to obtain a laser with a high-quality factor; therefore, the vertical cavity surface emitting laser based on the two-dimensional perovskite single crystal has the advantages of high environmental stability, adjustable emission wavelength along with the n value, low laser threshold and high quality factor.

Drawings

Fig. 1 shows a schematic two-dimensional structure of a three-dimensional perovskite.

Fig. 2a to 2c are schematic views showing two-dimensional structures of two-dimensional perovskite single layers of the present invention, in which N is 2 and N is 1, 2, and 3, respectively.

Fig. 3 is a schematic view showing a process flow of the fabrication of a two-dimensional perovskite single crystal-based vertical cavity surface emitting laser according to the present invention.

Fig. 4 is a schematic structural view of a two-dimensional perovskite single crystal-based vertical cavity surface emitting laser in the present invention.

Description of the element reference numerals

1 substrate

2 first reflecting mirror

201 titanium dioxide layer

202 silicon dioxide layer

3 silicon dioxide layer

4 two-dimensional perovskite single crystal

410. 420, 430 two-dimensional perovskite monolayers

5 silicon dioxide layer

6 second reflector

601 zinc sulfide layer

602 magnesium fluoride layer

Detailed Description

Referring to FIG. 1, the three-dimensional perovskite is formed from lead halide octahedra having common angles, such as PbI₆ ^4-、PbBr₆ ^4-And PbCl₆ ^4-And small volume organic ligands embedded in co-angular lead halide octahedral voids, e.g. CH₃NH³⁺. If bulky organic ligands which cannot intercalate into co-angular octahedral voids are used, e.g. C₄H₉NH³⁺And C₈H₉NH³⁺Instead of part of the small volume organic ligands, the three-dimensional perovskite can be separated into two-dimensional perovskites, see fig. 2 a-2 c. The two-dimensional perovskite has the characteristic of quantum well because the forbidden bandwidth of the bulky ligand is far larger than that of a perovskite layer, but the two-dimensional perovskite single layer in the two-dimensional perovskite single crystal is formed by small perovskite layers with different lead halide single layers due to the uneven distribution of the bulky ligand in the whole thin film of the composite two-dimensional perovskite thin film prepared by the spin coating method, so that the composite perovskite thin film has the advantages of single emission wavelength and a large number of interface defects and is not suitable for serving as a laser material.

The invention provides a method for preparing a two-dimensional perovskite single crystal by adopting a precursor solution self-assembly crystallization method, the two-dimensional perovskite single crystal can be transferred by using a mechanical stripping method and a dry method, and each two-dimensional perovskite single layer in the two-dimensional perovskite single crystal has the same n value, namely the same number of lead halide single layers, so that the emission wavelength of the two-dimensional perovskite single crystal is unique, and the emission wavelength can be adjusted along with the change of the n value in the two-dimensional perovskite single layer, and the threshold value of a laser is reduced; the interface defects of the two-dimensional perovskite single crystal are few, and the fluorescence quantum yield is high; the surface of the two-dimensional perovskite single crystal is smooth, so that a high-quality reflector can be grown on the two-dimensional perovskite single crystal to obtain a laser with a high-quality factor; therefore, the vertical cavity surface emitting laser based on the two-dimensional perovskite single crystal has the advantages of high environmental stability, adjustable emission wavelength along with the n value, low laser threshold and high quality factor.

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Please refer to fig. 2-4. It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.

Referring to fig. 4, the present embodiment provides a vertical cavity surface emitting laser based on a two-dimensional perovskite single crystal, which includes a substrate 1, a first reflecting mirror 2, a two-dimensional perovskite single crystal 4, and a second reflecting mirror 6; wherein the two-dimensional perovskite single crystal 4 comprises N two-dimensional perovskite single layers, and N is more than or equal to 2; the two-dimensional perovskite single layer comprises n layers of common-angle lead halide octahedrons, n-1 layers of organic ligands A and 2 layers of organic ligands B, wherein n is more than or equal to 1, the two-dimensional perovskite single layers have the same n value, the organic ligands A are embedded into the gaps of the common-angle lead halide octahedrons, the organic ligands B are respectively positioned on two opposite sides of the common-angle lead halide octahedrons, and the chemical formula of the two-dimensional perovskite single layer is B₂A_n-1Pb_nX_3n+1And X is a halogen element, and the number of carbon atoms of the organic ligand B is greater than that of the organic ligand A.

The two-dimensional perovskite single crystal 4 of the present embodiment has the organic ligand B of a large volume, so that water molecules can be effectively isolated to improve the environmental stability of the vertical cavity surface emitting laser; the energy gap of the large-volume organic ligand B is far larger than that of a perovskite layer, so that the two-dimensional perovskite single crystal 4 has the characteristic of a quantum well and the fluorescence quantum yield is high; the two-dimensional perovskite single crystal 4 is composed of the two-dimensional perovskite single layers with the same n value, so that the emission wavelength of the two-dimensional perovskite single crystal 4 is unique, the emission wavelength can be adjusted along with the change of the n value in the two-dimensional perovskite single layers, and the threshold value of a laser is reduced; the two-dimensional perovskite single crystal 4 has few interface defects and is suitable for being used as an optical gain material.

As an example, the vertical cavity surface emitting laser further includes a first adjustment layer between the first mirror 2 and the two-dimensional perovskite single crystal 4 and a second adjustment layer between the two-dimensional perovskite single crystal 4 and the second mirror 6, and the optical thicknesses of the first adjustment layer and the second adjustment layer are formed to be equal.

Specifically, the thickness of the two-dimensional perovskite single crystal 4 can be adjusted through the first adjusting layer and the second adjusting layer to meet the resonance condition of the laser, and the first adjusting layer and the second adjusting layer can also be used as protective layers to protect the first reflector 2 through the first adjusting layer, so that the damage to the first reflector 2 in the process is reduced, and similarly, the second adjusting layer can also be used as a protective layer of the two-dimensional perovskite single crystal 4 to reduce the damage to the two-dimensional perovskite single crystal 4 in the process; preferably, the first adjusting layer and the second adjusting layer have the same optical thickness and are made of the same material, that is, two symmetrical adjusting layers are formed, so that the standing wave field of the laser is distributed between the first reflector 2 and the second reflector 6, and the center of the standing wave field is strongest, so that the two-dimensional perovskite single crystal 4 is located at the strongest position of the standing wave field, and the threshold value of the laser is favorably reduced. In the present embodiment, as shown in fig. 4, the vcsel includes the first adjustment layer silicon dioxide layer 3 and the second adjustment layer silicon dioxide layer 5, wherein the optical thickness of the two-dimensional perovskite single crystal 4 is about 1/6 of the laser resonant wavelength, the total optical thickness of the silicon dioxide layer 3, the two-dimensional perovskite single crystal 4 and the silicon dioxide layer 5 can be 1/2 of the laser resonant wavelength by adjusting the thicknesses of the silicon dioxide layer 3 and the silicon dioxide layer 5, and the selection of the materials of the first adjustment layer and the second adjustment layer is not limited herein.

By way of example, the organic ligand A comprises CH₃NH₃ ⁺(ii) a The organic ligand B comprises C₄H₉NH₃ ⁺Or C₈H₉NH₃ ⁺(ii) a The X comprises one of I element, Cl element and Br element.

Specifically, the magnitude of the n value in the two-dimensional perovskite monolayer is determined by the ratio of the large volume of the organic ligand B to the small volume of the organic ligand a, and can be selected as needed. Due to the organic ligand B, water molecules can be effectively isolated, so that the environmental stability of the vertical cavity surface emitting laser can be improved. In this embodiment, the organic ligand A is CH₃NH₃ ⁺The organic ligand B adopts C₄H₉NH₃ ⁺The X is an element I, but is not limited to the element I, and the organic ligand B can also be C₈H₉NH₃ ⁺The X may also be Cl or Br, and is not limited herein.

As an example, the value range of N comprises N ≧ 10; the value range of n is more than or equal to 1 and less than or equal to 5.

Specifically, the value range of N includes N being greater than or equal to 10, such as 15, 20, etc.; the value range of n includes n is more than or equal to 1 and less than or equal to 5, such as any value of 1, 2, 3, 4 and 5; thereby providing said two-dimensional perovskite single crystal 4 with a certain thickness. Wherein the magnitude of the n value in the two-dimensional perovskite monolayer is determined by the ratio of the large volume of the organic ligand B and the small volume of the organic ligand A. Referring to fig. 2a to 2c, two-dimensional structural schematic diagrams of a two-dimensional perovskite single layer 410 with N-2 and N-1, a two-dimensional perovskite single layer 420 with N-2, and a two-dimensional perovskite single layer 430 with N-3 are shown, respectively. The two-dimensional perovskite single crystal 4 can be composed of any dozens of layers of the two-dimensional perovskite single layer with the same n value, so that the emission wavelength of the two-dimensional perovskite single crystal 4 is unique, and the emission wavelength of the two-dimensional perovskite single crystal 4 can be adjusted by adjusting the n value in the two-dimensional perovskite single layer, and the laser threshold value is reduced.

As an example, the two-dimensional perovskite single crystal 4 has a horizontal plane away from the surface of the substrate 1.

Specifically, the substrate 1 includes a quartz substrate, but is not limited thereto, and when the two-dimensional perovskite single crystal 4 has a horizontal surface far from the surface of the substrate 1, the surface of the two-dimensional perovskite single crystal 4 is flat, thereby facilitating the production of the second mirror 6 of high quality on the two-dimensional perovskite single crystal 4 to obtain a laser of high quality factor.

As an example, the reflectivity of the first mirror 2 is greater than 99.5% and the reflectivity of the second mirror 6 is less than 99%.

Specifically, in this embodiment, the vcsel adopts a top-emitting structure, so that the reflectivity of the first mirror 2 is preferably greater than 99.5% to provide the highest possible reflection for the resonant cavity, and the reflectivity of the second mirror 6 is less than 99% to provide partial reflection for the resonant cavity, and another part of light is emitted perpendicularly to the second mirror 6, but the vcsel is not limited to this structure, and may also be a bottom-emitting structure, and this is not limited too.

As an example, the first mirror 2 is a distributed bragg mirror, and includes a titanium dioxide layer 201 and a silicon dioxide layer 202 stacked in sequence, and optical thicknesses of the titanium dioxide layer 201 and the silicon dioxide layer 202 are 1/4 of the laser resonant wavelength respectively; the second reflector 6 is a distributed bragg reflector, and includes a zinc sulfide layer 601 and a magnesium fluoride layer 602 stacked in sequence, and the optical thicknesses of the zinc sulfide layer 601 and the magnesium fluoride layer 602 are 1/4 of the laser resonant wavelength respectively.

Specifically, in this embodiment, the first reflecting mirror 2 is formed by alternately stacking 7 titanium dioxide layers 201 and 6 silicon dioxide layers 202, optical thicknesses of the titanium dioxide layers 201 and the silicon dioxide layers 202 are 1/4 of the laser resonant wavelength, respectively, so that the laser resonant wavelength is located at the center of the reflection band of the first reflecting mirror 2, and the reflectivity of the first reflecting mirror 2 is greater than 99.5% to provide the highest reflection as possible for the resonant cavity. Said second mirror 6 is formed by 6 said zinc sulfide layers 601 and 5 said magnesium fluoride layers 602 stacked alternately, said zinc sulfide layers 601 and magnesium fluoride layers 602 each having an optical thickness of 1/4 of the laser resonance wavelength, so that the laser resonance wavelength is located at the center of the reflection band of said second mirror 6, said second mirror 6 having a reflectivity of less than 99% to provide partial reflection of the cavity, and another part of the light exiting perpendicularly to said second mirror 6. The selection of the structure and the material of the first reflecting mirror 2 and the second reflecting mirror 6 is not limited to this, and can be adaptively selected according to the specific structure and the requirement of the vertical cavity surface emitting laser.

Referring to fig. 3 and 4, the embodiment further provides a method for manufacturing a vertical cavity surface emitting laser based on a two-dimensional perovskite single crystal, which specifically includes the following steps:

providing a substrate 1;

forming a first reflector 2 on the substrate 1;

forming a two-dimensional perovskite single crystal 4 on the first reflector 2, wherein the two-dimensional perovskite single crystal 4 comprises N two-dimensional perovskite single layers, and N is more than or equal to 2; the two-dimensional perovskite single layer comprises n layers of common-angle lead halide octahedrons, n-1 layers of organic ligands A and 2 layers of organic ligands B, wherein n is more than or equal to 1, the two-dimensional perovskite single layers have the same n value, the organic ligands A are embedded into the gaps of the common-angle lead halide octahedrons, the organic ligands B are respectively positioned on two opposite sides of the common-angle lead halide octahedrons, and the chemical formula of the two-dimensional perovskite single layer is B₂A_n-1Pb_nX_3n+1X is a halogen element, and the number of carbon atoms of the organic ligand B is greater than that of the organic ligand A;

a second mirror 6 is formed on the two-dimensional perovskite single crystal 4.

As an example, a step of forming a first adjustment layer between the first reflecting mirror 2 and the two-dimensional perovskite single crystal 4 by an electron beam thermal evaporation method and a step of forming a second adjustment layer between the two-dimensional perovskite single crystal 4 and the second reflecting mirror 6 by an electron beam thermal evaporation method are further included, and the optical thicknesses of the first adjustment layer and the second adjustment layer are preferably equal.

Specifically, the thickness of the two-dimensional perovskite single crystal 4 can be adjusted by the first adjusting layer and the second adjusting layer to satisfy the resonance condition of the laser, and the first adjusting layer and the second adjusting layer can also be used as a protective layer to protect the first reflector 2 by the first adjusting layer, so as to reduce the damage to the first reflector 2 in the process, and similarly, the second adjusting layer can also be used as a protective layer of the two-dimensional perovskite single crystal 4 to reduce the damage to the two-dimensional perovskite single crystal 4 in the process, and in order to further reduce the damage, the first adjusting layer and the second adjusting layer are preferably prepared by the electron beam thermal evaporation method at a low temperature, which includes 60 ℃, but is not limited thereto. Preferably, the first adjusting layer and the second adjusting layer have the same optical thickness and are made of the same material, that is, two symmetrical adjusting layers are formed, so that the standing wave field of the laser is distributed between the first reflector 2 and the second reflector 6, and the center of the standing wave field is strongest, so that the two-dimensional perovskite single crystal 4 is located at the strongest position of the standing wave field, and the threshold value of the laser is favorably reduced.

By way of example, the optical thickness of the two-dimensional perovskite single crystal 4 is about 1/6 of the laser resonance wavelength, and the total optical thickness of the first adjusting layer, the two-dimensional perovskite single crystal 4 and the second adjusting layer can be 1/2 of the laser resonance wavelength through the thickness adjustment of the first adjusting layer and the second adjusting layer; the first adjusting layer comprises a silicon dioxide layer 3 and the second adjusting layer comprises a silicon dioxide layer 5.

By way of example, the organic ligand A comprises CH₃NH₃ ⁺(ii) a The organic ligand B comprises C₄H₉NH₃ ⁺Or C₈H₉NH₃ ⁺(ii) a The X comprises one of I element, Cl element and Br element.

As an example, the step of forming the two-dimensional perovskite single crystal 4 on the first reflecting mirror 2 includes:

forming a blocky two-dimensional perovskite single crystal by adopting a precursor solution self-assembly crystallization method;

stripping the blocky two-dimensional perovskite single crystal by adopting a mechanical stripping method to obtain a layered two-dimensional perovskite single crystal 4;

and transferring the layered two-dimensional perovskite single crystal 4 onto the first reflecting mirror 2 by adopting dry transfer.

As an example, an atomic force microscope is adopted to obtain the two-dimensional perovskite single crystal 4 with N being more than or equal to 10; the value range of n comprises that n is more than or equal to 1 and less than or equal to 5; the two-dimensional perovskite single crystal 4 is formed to have a horizontal plane away from the surface of the substrate 1.

As an example, a method of forming the first reflecting mirror 2 and the second reflecting mirror 6 includes an electron beam thermal evaporation method; the reflectivity of the first reflector 2 is more than 99.5%, and the reflectivity of the second reflector 6 is less than 99%.

As an example, the first mirror 2 is formed as a distributed bragg mirror, and includes a titanium dioxide layer 201 and a silicon dioxide layer 202 stacked in sequence, and optical thicknesses of the titanium dioxide layer 201 and the silicon dioxide layer 202 are 1/4 of a laser resonant wavelength respectively; the second mirror 6 is a distributed bragg mirror, and includes a zinc sulfide layer 601 and a magnesium fluoride layer 602 stacked in sequence, and the optical thicknesses of the zinc sulfide layer 601 and the magnesium fluoride layer 602 are 1/4 of the laser resonant wavelength respectively.

For the structure and material of the vertical cavity surface emitting laser, reference may be made to the above description of the vertical cavity surface emitting laser, and details are not described here. The following description is provided with reference to the fabrication of the vcsel by way of specific examples, but is not limited thereto, and may be selected according to specific needs, and may include the following steps:

with lead iodide (PbI)₂) Methylamine hydroiodide (CH)₃NH₂HI), butylamine hydroiodide (C)₄H₉NH₂HI) is taken as a precursor, and a precursor solution self-assembly crystallization method is utilized to prepare the blocky two-dimensional perovskite single crystal, wherein the value of the number n of lead iodide single layers in the subsequently formed two-dimensional perovskite single layer is controlled by the proportion of methylamine hydroiodide and butylamine hydroiodide;

peeling off the layered two-dimensional perovskite single crystal 4 consisting of dozens of two-dimensional perovskite single layers from the obtained bulk two-dimensional perovskite single crystal by using an adhesive tape by using a mechanical peeling method, and determining the thickness of the peeled two-dimensional perovskite single crystal 4 by using an atomic force microscope;

alternately depositing 7 titanium dioxide layers 201 and 6 silicon dioxide layers 202 on a quartz substrate in sequence by an electron beam thermal evaporation method to obtain the first reflecting mirror 2;

depositing said silicon dioxide layer 3 on said first mirror 2 by means of electron beam thermal evaporation to obtain said first conditioning layer;

transferring the two-dimensional perovskite single crystal 4 peeled off onto the silicon dioxide layer 3 by dry transfer;

depositing the silicon dioxide layer 5 on the two-dimensional perovskite single crystal 4 at 60 ℃ using an electron beam thermal evaporation method to obtain the second adjustment layer;

alternately depositing 6 of the zinc sulfide layers 601 and 5 of the magnesium fluoride layers 602 on the silicon dioxide layer 5 at 60 ℃ by an electron beam thermal evaporation method to obtain the second mirror 6.

In summary, the vertical cavity surface emitting laser based on the two-dimensional perovskite single crystal and the preparation method thereof utilize the two-dimensional perovskite single crystal as the optical gain material of the vertical cavity surface emitting laser, wherein the two-dimensional perovskite single crystal comprises N layers of two-dimensional perovskite single layers, and N is more than or equal to 2; the two-dimensional perovskite single layer comprises n layers of common-angle lead halide octahedrons, n-1 layers of organic ligands A and 2 layers of organic ligands B, wherein n is more than or equal to 1, and the two-dimensional perovskite single layer has phasesThe same n value, the organic ligand A is embedded into the common-angle lead halide octahedron gap, the organic ligand B is respectively positioned at the two opposite sides of the common-angle lead halide octahedron, and the chemical formula of the two-dimensional perovskite single layer is B₂A_n-1Pb_nX_3n+1And X is a halogen element, and the number of carbon atoms of the organic ligand B is greater than that of the organic ligand A. The large-volume organic ligand B in the two-dimensional perovskite single crystal can effectively isolate water molecules, so that the environmental stability of the vertical cavity surface emitting laser is improved; each two-dimensional perovskite single layer in the two-dimensional perovskite single crystal has the same n value, namely the two-dimensional perovskite single layers have the same number of lead halide single layers, so that the emission wavelength of the two-dimensional perovskite single crystal is unique, the emission wavelength can be adjusted along with the change of the n value in the two-dimensional perovskite single layer, and the threshold value of a laser is reduced; the interface defects of the two-dimensional perovskite single crystal are few, and the fluorescence quantum yield is high; the surface of the two-dimensional perovskite single crystal is smooth, so that a high-quality reflector can be grown on the two-dimensional perovskite single crystal to obtain a laser with a high-quality factor; therefore, the vertical cavity surface emitting laser based on the two-dimensional perovskite single crystal has the advantages of high environmental stability, adjustable emission wavelength along with the n value, low laser threshold and high quality factor.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.