Photoelectric material heterostructure and preparation method and application thereof
The preparation of halide perovskite epitaxial films on perovskite epitaxial substrates through gas-phase epitaxial technology, which solves the instability and anion diffusion problems of perovskite heterojunctions, and realizes the preparation of high-quality and high-stability perovskite film heterostructures, which are suitable for the preparation of a variety of optoelectronic devices.
Patent Information
- Application Number
- CN202510189269.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-20
- Publication Date
- 2025-05-27
AI Technical Summary
It is difficult to prepare high-quality and stable perovskite heterojunctions in the prior art, and there is a problem of anion diffusion, which affects device performance.
The halide perovskite epitaxial film is prepared on the perovskite epitaxial substrate through gas-phase epitaxial technology. The solid crystal lattice of the perovskite epitaxial substrate is used to suppress anion diffusion, forming a high-quality and high-stability perovskite film heterostructure.
The preparation of a centimeter-level single crystal perovskite film heterojunction has been realized, with excellent crystallinity, flatness and exciton state, and the surface is smooth and uniform, and is suitable for the preparation of micro-nano lasers, polarized excitation components and electroluminescent devices.
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Figure CN120051180A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of optoelectronic materials, and relates to an optoelectronic material heterostructure, a preparation method thereof, and an application thereof. Background Art
[0002] Metal halide perovskites have the advantages of adjustable bandgap, long photocarrier lifetime and diffusion length, and are a semiconductor optoelectronic material with broad application prospects, having great potential in the field of optoelectronics such as photovoltaics, light emission, and light detection. The structure of metal halide perovskites is similar to the crystal structure of the natural mineral calcium titanate tungsten oxide CaTiO 3 . Perovskite heterojunctions are an important part of perovskite optoelectronics, and the separation of photo-generated carriers and the radiative recombination of injected carriers occurring at the semiconductor heterojunction interface are the main factors affecting device performance.
[0003] For the conductive semiconductor heterojunction technology, such as methods like liquid phase epitaxy, metalorganic chemical vapor deposition, and molecular beam epitaxy, most of these technologies use high temperature, solvent treatment, and bombardment of atoms or atomic groups to fabricate perovskite heterojunctions. Due to the instability of perovskites and anion interdiffusion, it has hindered their preparation and research. For example, under high temperature conditions, the ion diffusion in perovskite heterojunctions will increase sharply, and finally form perovskite alloying products.
[0004] Most of the reported perovskite heterostructures use liquid phase epitaxy and selective anion exchange, but the dispersion degree of the heterostructure interface is always in the range of dozens of micrometers or even several millimeters, and there is no possibility of practical application. In addition, the heterojunction is based on bulk crystals and is not suitable for optoelectronic chip integration. From the perspective of the basic principles of materials, constructing perovskite heterostructures is quite challenging. In addition, integrated optoelectronic technology also puts forward more requirements: first, high-quality single-crystalline perovskite thin films with large area, uniformity, and material stability are required; second, simplify the processing process, avoid damaging perovskites while achieving functional heterostructures; finally, eliminate anion diffusion to ensure the stability of the heterostructure.
[0005] In summary, there is currently no high-quality optoelectronic material heterostructure, a preparation method thereof, and an application thereof. Summary of the Invention
[0006] Aiming at the deficiencies existing in the prior art, the purpose of the present invention is to provide an optoelectronic material heterostructure, a preparation method thereof, and an application thereof. Aiming at the problems that the instability of perovskite optoelectronic materials and serious anion interdiffusion make it impossible to prepare perovskite heterojunctions, the preparation method can prepare a high-quality and high-stability perovskite thin film heterostructure through vapor phase epitaxy, providing new ideas for applying perovskite heterostructures in the preparation of micro-nano lasers, polariton devices, electroluminescent devices, and photodetection fields.
[0007] To achieve the object of the present invention, the following technical solutions are adopted in the present invention:
[0008] In a first aspect, the present invention provides a method for preparing a heterostructure of optoelectronic materials, and the preparation method includes the following steps:
[0009] Using a protective gas as a carrier gas, chemically vapor depositing a halide perovskite epitaxial film on the surface of a perovskite epitaxial substrate;
[0010] The material of the perovskite epitaxial substrate includes any one of SrTiO 3 , KTaO 3 or SrTaO 3 . Typical but non-limiting combinations include the combination of SrTiO 3 and KTaO 3 , the combination of SrTiO 3 and SrTaO 3 , the combination of KTaO 3 and SrTaO 3 , or the combination of SrTiO 3 , KTaO 3 and SrTaO 3 .
[0011] In the prior art, in the method for assembling a perovskite heterojunction, such as liquid phase epitaxy, there is serious anion interdiffusion, resulting in alloying of the heterojunction, which will reduce the performance of the perovskite heterojunction; molecular beam epitaxy uses atomic or atomic group bombardment to manufacture a perovskite heterojunction, and the quality of the prepared heterojunction is poor.
[0012] In the process of preparing the heterostructure of optoelectronic materials in the present invention, the halide perovskite material undergoes vapor phase epitaxy on the perovskite epitaxial substrate. Since the crystal lattices between perovskites are similar, a centimeter-scale single crystal perovskite thin film heterojunction can be prepared, which has excellent crystallinity, single crystal flatness, sub-wavelength thickness, and strong exciton states. Due to the lossless van der Waals epitaxial integration, the perovskite heterojunction has a highly smooth and uniform surface; at the same time, the strong crystal lattice of the perovskite epitaxial substrate organizes the diffusion of anions from the halide perovskite epitaxial film, forming a sharp and clean heterojunction interface. The combination of the halide perovskite epitaxial film and the perovskite epitaxial substrate makes full use of the unique optoelectronic properties of the halide perovskite and the stability of the perovskite epitaxial substrate material, expands the perovskite material library of functional heterojunctions, provides a new method for forming functional heterojunctions for optoelectronics, and is applicable to the preparation of micro-nano lasers, polariton devices, and electroluminescent devices.
[0013] Preferably, the chemical vapor deposition includes sequentially performing dry heat treatment, constant pressure heat treatment, and deposition heat treatment.
[0014] Preferably, the temperature of the deposition heat treatment is 560°C - 600°C. For example, it can be 560°C, 570°C, 580°C, 590°C or 600°C, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.
[0015] Preferably, the time of the deposition heat treatment is 10 min - 40 min. For example, it can be 10 min, 15 min, 20 min, 25 min, 30 min, 35 min or 40 min, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.
[0016] Preferably, the temperature of the drying heat treatment is 145°C - 155°C and the time is 15 min - 25 min.
[0017] The temperature of the drying heat treatment is 145°C - 155°C. For example, it can be 145°C, 148°C, 150°C, 152°C or 155°C, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.
[0018] The time of the drying heat treatment is 15 min - 25 min. For example, it can be 15 min, 18 min, 20 min, 22 min, 24 min or 25 min, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.
[0019] Preferably, the temperature of the pressure stabilization heat treatment is 280°C - 320°C and the time is 8 min - 12 min.
[0020] The temperature of the pressure stabilization heat treatment is 280°C - 320°C. For example, it can be 280°C, 290°C, 300°C, 310°C or 320°C, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.
[0021] The time of the pressure stabilization heat treatment is 8 min - 12 min. For example, it can be 8 min, 9 min, 10 min, 11 min or 12 min, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.
[0022] Preferably, the pressure during the pressure stabilization heat treatment is stabilized at 45 Torr - 55 Torr. For example, it can be 45 Torr, 48 Torr, 50 Torr, 52 Torr, 54 Torr or 55 Torr, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.
[0023] Preferably, the carrier gas is nitrogen with a purity above 5N, such as 99.999%, 99.9993%, 99.9995%, 99.9998% or 99.9999%, but not limited to the listed values. Other unlisted values within the numerical range are equally applicable.
[0024] Preferably, the flow rate of the carrier gas is 25 sccm - 30 sccm, such as 25 sccm, 27 sccm, 28 sccm, 29 sccm or 30 sccm, but not limited to the listed values. Other unlisted values within the numerical range are equally applicable.
[0025] Preferably, the material of the halide perovskite epitaxial film includes CsPbX 3 , where X includes any one or a combination of at least two of Cl, Br or I. Typical but non - restrictive combinations include the combination of Cl and Br, the combination of Cl and I, the combination of Br and I, or the combination of Cl, Br and I.
[0026] Preferably, the surface of the perovskite epitaxial substrate is cleaned and dried with nitrogen before chemical vapor deposition.
[0027] Preferably, the cleaning includes ultrasonic cleaning for 8 min - 12 min in acetone, ethanol and isopropanol solutions respectively, such as 8 min, 9 min, 10 min, 11 min or 12 min, but not limited to the listed values. Other unlisted values within the numerical range are equally applicable.
[0028] Preferably, the chemical vapor deposition is carried out in a tube furnace.
[0029] As a preferred technical solution of the preparation method provided by the present invention, the preparation method includes the following steps:
[0030] (1) The perovskite epitaxial substrate is ultrasonically cleaned for 8 min - 12 min in acetone, ethanol and isopropanol solutions respectively, and then dried with nitrogen;
[0031] (2) The perovskite powder is placed in a quartz boat and placed in the heating source area of the tube furnace, and the perovskite epitaxial substrate is placed in the low - temperature downstream area of the tube furnace;
[0032] The material of the perovskite epitaxial substrate includes SrTiO 3 , KTaO 3 or SrTaO 3 any one of them;
[0033] The material of the perovskite powder includes CsPbX 3 , where X includes any one or a combination of at least two of Cl, Br or I;
[0034] (3) Set up a gradient temperature control program. First, perform a drying heat treatment at a temperature of 145°C - 155°C for 15 min - 25 min; then perform a constant pressure heat treatment at a temperature of 280°C - 320°C for 8 min - 12 min. At the same time, keep the pressure of the system stable at 45 Torr - 55 Torr. Under the condition of stable gas pressure, introduce nitrogen with a flow rate of 25 sccm - 30 sccm as the carrier gas, and perform a deposition heat treatment at a temperature of 560°C - 600°C for 10 min - 40 min; cool to room temperature to achieve the growth of the halide perovskite epitaxial film.
[0035] In the second aspect, the present invention provides a photoelectric material heterostructure, which is prepared by using the preparation method described in the first aspect.
[0036] In the third aspect, the present invention provides an application of the photoelectric material heterostructure described in the second aspect, and the photoelectric material heterostructure is used for micro - nano lasers, polariton devices, electroluminescent devices or photodetector devices.
[0037] The numerical ranges described in the present invention not only include the point values exemplified above, but also include any point values between the above - mentioned numerical ranges not exemplified. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the ranges.
[0038] Compared with the prior art, the present invention has the following beneficial effects:
[0039] In the process of preparing the photoelectric material heterostructure of the present invention, the halide perovskite material undergoes vapor - phase epitaxy on the perovskite epitaxial substrate. Due to the similar crystal lattices between perovskites, a centimeter - scale single - crystal perovskite thin - film heterojunction can be prepared, which has excellent crystallinity, single - crystal flatness, sub - wavelength thickness, and strong exciton states. Due to the lossless van der Waals epitaxial integration, the perovskite heterojunction has a highly smooth and uniform surface; at the same time, the strong crystal lattice of the perovskite epitaxial substrate prevents the diffusion of anions from the halide perovskite epitaxial film, forming a sharp and clean heterojunction interface. The combination of the halide perovskite epitaxial film and the perovskite epitaxial substrate makes full use of the unique optoelectronic properties of the halide perovskite and the stability of the perovskite epitaxial substrate material, expands the perovskite material library of functional heterojunctions, provides a new method for forming functional heterojunctions for optoelectronics, and is applicable to the preparation of micro - nano lasers, polariton devices, and electroluminescent devices. Description of the Drawings
[0040] Figure 1 It is an atomic schematic diagram of the photoelectric material heterostructure obtained in Example 1.
[0041] Figure 2It is a physical diagram of the optoelectronic material heterostructure obtained in Example 1.
[0042] Figure 3 It is a microscope image of the optoelectronic material heterostructure obtained in Example 1.
[0043] Figure 4 It is a fluorescence microscope image of the optoelectronic material heterostructure obtained in Example 1.
[0044] Figure 5 It is a scanning electron microscope image of the optoelectronic material heterostructure obtained in Example 1.
[0045] Figure 6 It is the atomic force microscope height map and roughness map of the optoelectronic material heterostructure obtained in Example 1.
[0046] Figure 7 It is the X-ray diffraction pattern of the optoelectronic material heterostructure obtained in Example 1.
[0047] Figure 8 It is the absorption spectrum of the optoelectronic material heterostructure obtained in Example 1.
[0048] Figure 9 It is the fluorescence spectrum of the optoelectronic material heterostructure obtained in Example 1.
[0049] Figure 10 It is a microscope image of the optoelectronic material heterostructure obtained in Example 2.
[0050] Figure 11 It is a fluorescence microscope image of the optoelectronic material heterostructure obtained in Example 2.
[0051] Figure 12 It is a physical diagram of the optoelectronic material heterostructure obtained in Example 3.
[0052] Figure 13 It is a microscope image of the optoelectronic material heterostructure obtained in Example 4.
[0053] Figure 14 It is the atomic force microscope height map and roughness map of the optoelectronic material heterostructure obtained in Example 4.
[0054] Figure 15 It is the atomic force microscope height map and roughness map of the optoelectronic material heterostructure obtained in Example 5.
[0055] Figure 16 It is a physical diagram of the optoelectronic material structure obtained in Comparative Example 1.
[0056] Figure 17 It is a microscope image of the optoelectronic material structure obtained in Comparative Example 1. Detailed implementation manners
[0057] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.
[0058] Example 1
[0059] This embodiment provides a preparation method of a heterostructure of optoelectronic materials. The preparation method includes the following steps:
[0060] Prepare halide perovskite: Dissolve 10 mmol of PbBr 2 powder in 8 mL of hydrobromic acid and stir until completely dissolved to obtain solution A; dissolve 10 mmol of CsBr in 3 mL of water to obtain solution B; dropwise add solution B into solution A to form an orange precipitate; after filtration and washing with ethanol, the precipitate is dried in a vacuum oven at 60 °C for 12 h to obtain CsPbBr 3 perovskite powder;
[0061] (1) Ultrasonically clean the SrTiO 3 perovskite epitaxial substrate in acetone, ethanol, and isopropyl alcohol solutions for 10 min respectively, and then dry it with nitrogen gas;
[0062] (2) Place 100 mg of CsPbBr 3 perovskite powder in a quartz boat and place it in the heating source area of a tube furnace, and place the perovskite epitaxial substrate in the low-temperature downstream area of the tube furnace;
[0063] (3) Set a gradient temperature control program. First, perform drying heat treatment at a temperature of 150 °C for 20 min; then perform constant pressure heat treatment at a temperature of 300 °C for 10 min, and at the same time, keep the pressure of the system stable at 50 Torr. Under the condition of stable gas pressure, introduce nitrogen gas (purity 5N) with a flow rate of 30 sccm as the carrier gas, and perform deposition heat treatment at a temperature of 575 °C for 30 min; cool to room temperature to realize the growth of the halide perovskite epitaxial thin film and prepare the heterostructure of optoelectronic materials.
[0064] Figure 1 is the atomic schematic diagram of the heterostructure of optoelectronic materials obtained in this embodiment; Figure 2 is the physical diagram of the heterostructure of optoelectronic materials obtained in this embodiment; Figure 3 is the microscope image of the heterostructure of optoelectronic materials obtained in this embodiment; Figure 4 is the fluorescence microscope image of the heterostructure of optoelectronic materials obtained in this embodiment;
[0065] Figure 5 is the scanning electron microscope image of the heterostructure of optoelectronic materials obtained in this embodiment; Figure 6The atomic force microscope height map and roughness map of the optoelectronic material heterostructure obtained in this example; Figure 7 The X-ray diffraction pattern of the optoelectronic material heterostructure obtained in this example; Figure 8 The absorption spectrum of the optoelectronic heterostructure obtained in this example; Figure 9 The fluorescence spectrum of the optoelectronic heterostructure obtained in this example.
[0066] As Figure 1 shown, in the optoelectronic material heterostructure obtained in this example, the crystal parameters of the perovskite epitaxial substrate and the halide perovskite epitaxial thin film are similar. The physical picture is as Figure 2 shown, with an area of 1×1 cm 2 . From Figures 3 - 5 it can be seen that the surface of the optoelectronic material heterostructure obtained in this example is smooth and the luminescence is uniform. As Figure 6 shown, the halide perovskite epitaxial thin film has a certain uniform thickness, a smooth surface without grain boundaries, and a thickness of about 399 nm. From Figure 7 it can be seen that the crystal quality of the optoelectronic material heterostructure obtained in this example is good, the film orientation is consistent, the orientation of the halide perovskite epitaxial thin film is (101), and it has single crystal properties. From Figure 8 and Figure 9 it can be seen that the absorption spectrum peak and fluorescence spectrum peak of the optoelectronic material heterostructure are 518 nm and 542 nm respectively, with bright green fluorescence and strong exciton states, and are suitable for micro-nano lasers, polariton devices and electroluminescent devices.
[0067] Example 2
[0068] This example provides a preparation method of an optoelectronic material heterostructure. Except that the SrTiO 3 perovskite epitaxial substrate is replaced with a KTaO 3 perovskite epitaxial substrate, the rest are the same as in Example 1.
[0069] The steps and parameters for preparing the halide perovskite are the same as those in Example 1;
[0070] (1) The KTaO 3 perovskite epitaxial substrate is ultrasonically cleaned in acetone, ethanol and isopropanol solutions for 10 min respectively, and then dried with nitrogen;
[0071] (2) 100 mg of CsPbBr 3 perovskite powder is placed in a quartz boat and placed in the heating source area of a tube furnace, and the perovskite epitaxial substrate is placed in the low-temperature downstream area of the tube furnace;
[0072] (3) Set the gradient temperature control program. First, perform drying heat treatment at 150 °C for 20 min; then perform constant pressure heat treatment at 300 °C for 10 min. At the same time, stabilize the pressure of the system at 50 Torr. Under the condition of stable gas pressure, introduce nitrogen (purity 5N) with a flow rate of 30 sccm as the carrier gas, and perform deposition heat treatment at 575 °C for 30 min; cool to room temperature to achieve the growth of the halide perovskite epitaxial film and prepare the optoelectronic material heterostructure.
[0073] Figure 10 This is the micrograph of the optoelectronic material heterostructure obtained in this example; Figure 11 This is the fluorescence micrograph of the optoelectronic material heterostructure obtained in this example. From Figure 10 and Figure 11 it can be seen that the surface of the optoelectronic material heterostructure obtained in this example is smooth and the luminescence is uniform.
[0074] Example 3
[0075] This example provides a preparation method of an optoelectronic material heterostructure. Except that the SrTiO 3 perovskite epitaxial substrate is replaced with the SrTaO 3 perovskite epitaxial substrate, the rest are the same as in Example 1.
[0076] The steps and parameters for preparing the halide perovskite are the same as in Example 1;
[0077] (1) The SrTaO 3 perovskite epitaxial substrate is ultrasonically cleaned in acetone, ethanol and isopropanol solutions for 10 min respectively, and then dried with nitrogen;
[0078] (2) 100 mg of CsPbBr 3 perovskite powder is placed in a quartz boat and placed in the heating source area of the tube furnace, and the perovskite epitaxial substrate is placed in the low-temperature downstream area of the tube furnace;
[0079] (3) Set the gradient temperature control program. First, perform drying heat treatment at 150 °C for 20 min; then perform constant pressure heat treatment at 300 °C for 10 min. At the same time, stabilize the pressure of the system at 50 Torr. Under the condition of stable gas pressure, introduce nitrogen (purity 5N) with a flow rate of 30 sccm as the carrier gas, and perform deposition heat treatment at 575 °C for 30 min; cool to room temperature to achieve the growth of the halide perovskite epitaxial film and prepare the optoelectronic material heterostructure.
[0080] Figure 12 This is the physical picture of the optoelectronic material heterostructure obtained in this example. From Figure 12It can be seen that the area of the optoelectronic material heterostructure obtained in this embodiment is 2×2.5 cm 2 , with a smooth surface and uniform luminescence.
[0081] Example 4
[0082] This embodiment provides a method for preparing an optoelectronic material heterostructure, and the preparation method includes the following steps:
[0083] The steps and parameters for preparing the halide perovskite are the same as those in Example 1;
[0084] (1) SrTiO 3 The perovskite epitaxial substrate is ultrasonically cleaned in acetone, ethanol, and isopropanol solutions for 8 min, and then dried with nitrogen gas;
[0085] (2) 100 mg of CsPbBr 3 The perovskite powder is placed in a quartz boat and placed in the heating source area of the tube furnace, and the perovskite epitaxial substrate is placed in the low-temperature downstream area of the tube furnace;
[0086] (3) Set a gradient temperature control program. First, perform a drying heat treatment at a temperature of 145 °C for 25 min; then perform a pressure-stabilizing heat treatment at a temperature of 280 °C for 12 min, while stabilizing the pressure of the system at 45 Torr. Under the condition of stable gas pressure, introduce nitrogen gas (purity 5N) with a flow rate of 25 sccm as the carrier gas, and perform a deposition heat treatment at a temperature of 560 °C for 40 min; cool to room temperature to realize the growth of the halide perovskite epitaxial thin film and prepare the optoelectronic material heterostructure.
[0087] Figure 13 is the microscope image of the optoelectronic material heterostructure obtained in this embodiment; Figure 14 are the atomic force microscope height map and roughness map of the optoelectronic material heterostructure obtained in this embodiment. It can be seen from Figure 13 that the surface of the optoelectronic material heterostructure obtained in this embodiment is smooth and the luminescence is uniform. As Figure 14 shown, the halide perovskite epitaxial thin film has a certain uniform thickness, a smooth surface without grain boundaries, and the thickness is about 920 nm.
[0088] Example 5
[0089] This embodiment provides a method for preparing an optoelectronic material heterostructure, and the preparation method includes the following steps:
[0090] The steps and parameters for preparing the halide perovskite are the same as those in Example 1;
[0091] (1) SrTiO 3The perovskite epitaxial substrate was ultrasonically cleaned in acetone, ethanol, and isopropyl alcohol solutions for 12 min respectively, and then dried with nitrogen gas;
[0092] (2) 100 mg of CsPbBr 3 The perovskite powder was placed in a quartz boat and positioned in the heating source area of a tube furnace, and the perovskite epitaxial substrate was placed in the low-temperature downstream area of the tube furnace;
[0093] (3) A gradient temperature control program was set. First, it was dried and heat-treated at 155 °C for 15 min; then it was pressure-stabilized and heat-treated at 320 °C for 8 min. At the same time, the pressure of the system was stabilized at 55 Torr. Under the condition of stable gas pressure, nitrogen gas (purity 5N) with a flow rate of 28 sccm was introduced as the carrier gas, and it was deposited and heat-treated at 600 °C for 10 min; it was cooled to room temperature to achieve the growth of the halide perovskite epitaxial film, and a heterostructure of optoelectronic materials was prepared.
[0094] Figure 15 This is the atomic force microscope height map and roughness map of the heterostructure of optoelectronic materials obtained in this example. As can be seen from Figure 15 it, the halide perovskite epitaxial film obtained in this example has a certain thickness, about 135 nm.
[0095] Comparative Example 1
[0096] This comparative example provides a preparation method of an optoelectronic material structure, and the preparation method includes the following steps:
[0097] The steps and parameters for preparing the halide perovskite are the same as those in Example 1;
[0098] (1) The single-crystalline silicon substrate was ultrasonically cleaned in acetone, ethanol, and isopropyl alcohol solutions for 10 min respectively, and then dried with nitrogen gas;
[0099] (2) 100 mg of CsPbBr 3 The perovskite powder was placed in a quartz boat and positioned in the heating source area of a tube furnace, and the single-crystalline silicon substrate was placed in the low-temperature downstream area of the tube furnace;
[0100] (3) A gradient temperature control program was set. First, it was dried and heat-treated at 150 °C for 20 min; then it was pressure-stabilized and heat-treated at 300 °C for 10 min. At the same time, the pressure of the system was stabilized at 50 Torr. Under the condition of stable gas pressure, nitrogen gas (purity 5N) with a flow rate of 30 sccm was introduced as the carrier gas, and it was deposited and heat-treated at 575 °C for 30 min; it was cooled to room temperature to achieve the growth of the halide perovskite epitaxial structure.
[0101] Figure 16This is a physical picture of the photoelectric material structure obtained in this comparative example. Figure 17 This is a microscope image of the structure of the optoelectronic material obtained in this comparative example. Figure 16 and Figure 17 As shown, in the optoelectronic material structure obtained in this comparative example, the result obtained by growing halide perovskite on the perovskite epitaxial substrate is disordered island-shaped polycrystalline particles, indicating that the silicon substrate cannot be used as an epitaxial substrate for preparing the halide perovskite optoelectronic material heterojunction.
[0102] In summary, in the process of preparing the heterostructure of optoelectronic materials of the present invention, the halide perovskite material undergoes vapor phase epitaxy on the perovskite epitaxial substrate. Since the lattices between the perovskites are similar, a centimeter-level single crystal perovskite thin film heterojunction can be prepared, which has excellent crystallinity, single crystal flatness, subwavelength thickness and strong exciton state. Due to the lossless van der Waals epitaxial integration, the perovskite heterojunction has a highly smooth and uniform surface; at the same time, the solid lattice of the perovskite epitaxial substrate organizes the diffusion of anions from the halide perovskite epitaxial film, forming a sharp and clean heterojunction interface. The combination of the halide perovskite epitaxial film and the perovskite epitaxial substrate makes full use of the unique optoelectronic properties of the halide perovskite and the stability of the perovskite epitaxial substrate material, expands the perovskite material library of functional heterojunctions, and provides a new method for forming functional heterojunctions for optoelectronics, which is suitable for the preparation of micro-nano lasers, polaritons and electroluminescent devices.
[0103] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.
Claims
1. A method for preparing a heterostructure of optoelectronic materials, characterized in that: The preparation method comprises the following steps: The protective gas is used as a carrier gas to chemically vapor deposit a halide perovskite epitaxial film on the surface of the perovskite epitaxial substrate; The material of the perovskite epitaxial substrate includes any one of SrTiO3, KTaO3 or SrTaO3.
2. The preparation method according to claim 1, characterized in that: The chemical vapor deposition includes a drying heat treatment, a pressure stabilization heat treatment and a deposition heat treatment which are performed in sequence.
3. The preparation method according to claim 2, characterized in that: The temperature of the deposition heat treatment is 560°C-600°C, and the time is 10min-40min; And / or, the temperature of the drying heat treatment is 145°C-155°C, and the time is 15min-25min; And / or, the temperature of the pressure stabilization heat treatment is 280°C-320°C, and the time is 8min-12min; And / or, the pressure during the steady-pressure heat treatment is stabilized at 45 Torr-55 Torr.
4. The preparation method according to claim 1, characterized in that: The carrier gas is nitrogen with a purity of 5N or above; And / or, the flow rate of the carrier gas is 25 sccm-30 sccm.
5. The preparation method according to claim 1, characterized in that: The material of the halide perovskite epitaxial film includes CsPbX3, wherein X includes any one of Cl, Br or I or a combination of at least two of them.
6. The preparation method according to claim 1, characterized in that: The surface of the perovskite epitaxial substrate is cleaned and dried with nitrogen before chemical vapor deposition; And / or, the cleaning comprises ultrasonic cleaning in acetone, ethanol and isopropanol solutions for 8 min-12 min respectively.
7. The preparation method according to any one of claims 1 to 6, characterized in that: The chemical vapor deposition is carried out in a tube furnace.
8. The preparation method according to claim 1, characterized in that: The preparation method comprises the following steps: (1) The perovskite epitaxial substrate was ultrasonically cleaned in acetone, ethanol and isopropanol solutions for 8 min to 12 min respectively, and then dried with nitrogen; (2) placing the perovskite powder in a quartz boat, placing it in the heating source area of a tube furnace, and placing the perovskite epitaxial substrate in the low-temperature downstream area of the tube furnace; The material of the perovskite epitaxial substrate includes any one of SrTiO3, KTaO3 or SrTaO3; The material of the perovskite powder includes CsPbX3, wherein X includes any one of Cl, Br or I or a combination of at least two thereof; (3) Setting a gradient temperature control program, first performing a drying heat treatment at a temperature of 145°C-155°C for 15min-25min; then performing a constant pressure heat treatment at a temperature of 280°C-320°C for 8min-12min, while stabilizing the pressure of the system at 45Torr-55Torr. Under the condition of stable pressure, introducing nitrogen at a flow rate of 25sccm-30sccm as a carrier gas, and performing a deposition heat treatment at a temperature of 560°C-600°C for 10min-40min; cooling to room temperature to achieve the growth of a halide perovskite epitaxial film.
9. A photoelectric material heterostructure, characterized in that: The optoelectronic material heterostructure is prepared by the preparation method described in any one of claims 1 to 8.
10. An application of the optoelectronic material heterostructure as claimed in claim 9, characterized in that: The optoelectronic material heterostructure is used for micro-nano lasers, polaritons, electroluminescent devices or photoelectric detection devices.