Preparation Method of Two-Dimensional Single-Crystalline Rare Earth Compound Nanosheets

Abstract

The present invention provides a method for preparing two-dimensional single-crystalline rare-earth compound nanosheets, which relates to the technical field of nanomaterials. Among them, the method for preparing two-dimensional single-crystalline rare-earth compound nanosheets includes: placing a substrate material into a reaction chamber; introducing reactant gases into the reaction chamber through a carrier gas, and controlling the flow rate and proportion of the carrier gas; simultaneously heating the reaction chamber and controlling the heating rate and temperature; the reactants include a source material and a catalyst, the source material is a rare-earth element compound, and the catalyst is a non-metal catalyst; the mass ratio of the source material to the catalyst is 7:1 to 9:1; the solid substance generated by the reaction is deposited on the surface of the substrate material to form a film or a coating, thereby obtaining two-dimensional single-crystalline rare-earth compound nanosheets. The present invention can efficiently prepare single-crystalline rare-earth compound nanomaterials with high quality and high rare-earth element concentration.

Description

Technical Field

[0001] The present invention relates to the technical field of nanomaterials, and particularly to a method for preparing two-dimensional single-crystalline rare earth compound nanosheets. Background Art

[0002] The 1.5-μm band, as the best window for optical fiber communication, plays a crucial role in optical communication systems due to its low loss and high transmission efficiency characteristics. Rare earth elements, such as erbium (Er) element, have become a hot research material in the field of optical communication because of their excellent luminescence characteristics in the 1.5-μm communication band. Among them, the unique 4f electronic structure of erbium endows it with rich magnetic, electrical, and optical properties, providing the possibility for the preparation of high-performance electronic devices such as field-effect transistors, magnetic memories, and sensors. At the same time, erbium also shows extensive application potential in the fields of biomedicine, energy storage catalysis, etc. The quality of the material ultimately determines the performance of the device. Therefore, in the research and development of related devices, it is crucial to obtain high crystal quality and high erbium concentration.

[0003] In the field of optoelectronic devices, traditional erbium-doped materials have a low Er ion concentration, which limits the optical gain per unit length, making the devices based on erbium-doped materials large in size and difficult to integrate. This not only increases the preparation cost of the devices but also limits their application in high-integration optoelectronic systems. Recent research has found that due to the regular periodic arrangement of Er compounds, the Er ion concentration is increased by 2-3 orders of magnitude compared with traditional erbium-doped materials, and the concentration quenching phenomenon is effectively alleviated, providing higher gain. This high-concentration Er ion distribution brings significant advantages to Er compounds in optoelectronic devices such as optical amplifiers and lasers. Therefore, the synthesis and preparation of Er compounds and related devices that are easy to integrate with silicon-based materials have become a hot issue in silicon-based optoelectronics research.

[0004] Two-dimensional rare earth compound nanosheets refer to two-dimensional layered materials composed of rare earth elements and other elements, and their thickness is usually between several atomic layers and dozens of nanometers. Since the layers of the material are connected by van der Waals forces, it provides a new idea for silicon-based heterogeneous integration. In addition, due to their unique electronic structure and quantum confinement effect, these two-dimensional materials exhibit many novel physical phenomena, such as the quantum spin Hall effect, topological insulators, superconductivity, etc. The preparation of single-crystalline two-dimensional rare earth compound nanosheets provides an ideal platform for studying the structure-property relationship of materials. By regulating the composition, structure, and dimension of the material, its physical and chemical properties can be systematically studied, providing theoretical guidance for the design of new functional materials.

[0005] Traditional methods for synthesizing Er compound materials include solvothermal method, hydrothermal method, atomic layer deposition method, etc. These methods often face problems such as complex growth process, metal catalysis, and difficulty in large-scale batch production. For example, solvothermal method and hydrothermal method usually need to be carried out under high temperature and high pressure conditions, and the growth process is difficult to control, resulting in unstable product quality. In addition, the sol-gel method reported in the prior art to grow Er2SiO5 is to synthesize Er2SiO5 solution by liquid phase reaction, and evaporate the liquid phase to form a thin film after spin coating the solution on the substrate surface. This method produces a polycrystalline thin film with many material defects and low luminescence efficiency. The method of growing Er2O3 by ALD method is to accurately control the dosage and supply gaseous precursor source materials in a high vacuum reaction chamber in steps, and grow Er2O3 thin film on the substrate surface at a deposition speed of atomic layer thickness, but this method has a slow growth rate and is not conducive to large-scale growth. At present, the preparation method of two-dimensional rare earth compound nanosheets is not mature enough, and it is difficult to obtain high-quality single crystal nanosheets. Therefore, it is urgent to develop new preparation methods to improve the crystallization quality and size of nanosheets.

[0006] Chemical vapor deposition (CVD) is a technology widely used in the preparation of nanomaterials. It deposits nanomaterials on the surface of a substrate through a gas phase reaction. The principle of CVD technology is simple and has good controllability. It is suitable for the preparation of various nanomaterials, such as carbon nanotubes, graphene, transition metal sulfides (TMDs), etc. Although CVD has high growth control accuracy, it usually requires metal catalysts, which increases the cost and complexity of preparation. For example, the method of growing ECS ​​nanowires by CVD is to heat the precursor source in a tube furnace to vaporize it, transport it through a carrier gas, and chemically react in the gas state or near the substrate surface to grow Er3Cl(SiO4)2 nanowires. However, this method is difficult to operate, requires particle catalysis, and is costly.

[0007] Therefore, how to efficiently and low-cost prepare rare earth compound nanomaterials with high crystal quality and high rare earth element concentration is a technical problem that needs to be solved urgently. Summary of the invention

[0008] In view of the above problems existing in the prior art, the present invention provides a method for preparing a two-dimensional single-crystal rare earth compound nanosheet, so as to efficiently and low-cost prepare a rare earth nanomaterial with higher crystal quality and higher rare earth element concentration.

[0009] The invention provides a method for preparing a two-dimensional single crystal rare earth compound nanosheet, which adopts a chemical vapor deposition method to generate the rare earth compound nanosheet on a substrate material, and comprises the following steps.

[0010] (1) Placing the substrate material into the reaction chamber;

[0011] (2) The reactant gas enters the reaction chamber through the carrier gas, and the flow rate and proportion of the carrier gas are controlled; meanwhile, the reaction chamber is heated, and the heating rate and temperature are controlled; the reactants include a source material and a catalyst, the source material is a rare earth element compound, and the catalyst is a non-metal catalyst; the mass ratio of the source material to the catalyst is 7:1 to 9:1.

[0012] (3) The solid substance generated by the reaction is deposited on the surface of the substrate material to form a thin film or a coating, and a single-crystal rare earth compound nanosheet is obtained.

[0013] According to a method for preparing a two-dimensional single-crystal rare earth compound nanosheet provided by the present invention, the rare earth element compound is a compound with a high rare earth element ion content; preferably dysprosium compound, holmium compound, erbium compound, thulium compound, ytterbium compound, lutetium compound; preferably erbium compound. In the examples of the present invention, ErCl3 is selected as the source material. Those skilled in the art should understand that any erbium compound with a high Er ion content can be selected as the source material, not limited to ErCl3.

[0014] According to a method for preparing a single-crystal rare earth compound nanosheet provided by the present invention, the non-metal catalyst is sodium chloride, potassium chloride, or an alkali metal chloride. In the examples of the present invention, NaCl is selected as the catalyst to promote the growth of the Er compound. NaCl has good thermal stability and catalytic performance, can effectively promote the growth of the Er compound at high temperature, and avoids the use of metal catalysts.

[0015] According to a method for preparing a two-dimensional single-crystal rare earth compound nanosheet provided by the present invention, in step (1), the substrate material is selected from silicon, silicon carbide, quartz, metal foil, germanium, gallium arsenide, and / or gallium nitride materials; and / or

[0016] Before step (1), there is also a step of pre-treating the substrate material, and the pre-treatment is: using organic solvents (such as acetone, isopropyl alcohol) and deionized water to ultrasonically clean the substrate material to remove organic pollutants and impurities on the surface, drying the cleaned substrate material to remove residual moisture and solvents; and / or activating the surface of the substrate by plasma treatment, surface hydrophilic modification, physical vapor deposition, or chemical pickling treatment methods to improve the bonding force between the substrate material and the reactants.

[0017] In the specific implementation process, a suitable carrier gas and the flow rate of the carrier gas can be selected according to the reaction requirements of the rare earth compound and the non-metal catalyst.

[0018] In the method for preparing the above-mentioned two-dimensional single-crystalline rare-earth compound nanosheets provided by the present invention, the carrier gas in step (2) is a mixed gas of argon and hydrogen, and the mixing ratio of argon to hydrogen is 95:5; or the carrier gas in step (2) is one of argon and nitrogen; the flow rate of the carrier gas is 20-100 standard cubic centimeters per minute.

[0019] According to the method for preparing a two-dimensional single-crystalline rare-earth compound nanosheet provided by the present invention, the heating rate in step (2) is 18-21 °C per minute, and the temperature is 750 °C - 1000 °C; and / or the temperature is maintained for 20-60 minutes.

[0020] Under high-temperature conditions, the rare-earth compound and the non-metal catalyst as source materials undergo a chemical reaction on the surface of the substrate to grow two-dimensional single-crystalline rare-earth compound nanosheets. The reaction growth process usually requires a certain amount of time, and the specific reaction time depends on the type of single-crystalline rare-earth compound nanosheets to be grown and the growth conditions. In the examples of the present invention, the time for preparing the erbium compound nanomaterial starts from heating to the target temperature, and the temperature is maintained at 900 °C for 60 minutes.

[0021] After obtaining the single-crystalline rare-earth compound nanosheets in step (3) of the method for preparing a two-dimensional single-crystalline rare-earth compound nanosheet provided by the present invention, it further includes the steps of cooling the temperature of the reaction chamber, discharging the remaining reactant gases and the carrier gas, and transferring the grown nanomaterial from the substrate material through micro-nano transfer technology. Usually, it is cooled to room temperature. The cooling process is usually achieved by natural cooling or forced cooling to ensure that the nanomaterial does not undergo structural changes during the cooling process. The remaining reaction gases are discharged from the reaction chamber through a vacuum pump to ensure the cleanliness of the inside of the reaction chamber.

[0022] The high-quality single-crystalline compound obtained by growth in the present invention can be subsequently transferred from the substrate to the target substrate through micro-nano transfer technology, specifically dry transfer, to realize highly efficient coupling devices that can be integrated with silicon, such as silicon-based light sources and silicon-based optical amplifiers. Methods such as heat treatment, chemical treatment, or plasma treatment can be used to remove residual reactants and pollutants, improving the purity and stability of the nanomaterial.

[0023] The present invention also provides a two-dimensional single-crystalline rare-earth compound nanosheet, which is prepared by the preparation method as described above.

[0024] Furthermore, the two-dimensional single-crystalline rare-earth compound nanosheet provided by the present invention is a single-crystalline erbium compound nanosheet.

[0025] The method for preparing single-crystal erbium compound nanosheets provided by the present invention includes: (1) placing the substrate material silicon into the reaction chamber; (2) introducing the reactant gas into the reaction chamber through the carrier gas (the mixing ratio of argon and hydrogen is 95:5), controlling the carrier gas flow rate at 25 sccm (standard cubic centimeters per minute); simultaneously heating the reaction chamber, controlling the heating rate at 20 °C per minute and heating to 900 °C, and maintaining this temperature for 60 minutes; the reactants include the source material ErCl3 and the catalyst NaCl, and the mass ratio of ErCl3 to NaCl is 8:1; (3) depositing the solid substance generated by the reaction on the surface of the substrate material to obtain two-dimensional single-crystal rare-earth compound nanosheets.

[0026] The present invention also provides a product containing the single-crystal rare-earth compound nanosheets as described above; the product includes optical communication devices, coupling devices, field effect transistors, photodetectors, solar cells, magnetic memories, biosensors, gas sensors, biofluorescent labeling instruments, quantum information devices, solid lighting components, lasers, amplifiers, catalysts, fuel cells, or high-temperature superconducting materials.

[0027] The present invention also provides any one of the following applications of the above preparation method or the single-crystal rare-earth compound nanosheets as described above:

[0028] (1) Amplifying optical signals;

[0029] (2) Preparing fuel cells, lasers, catalysts, detectors, magnetic memories, sensors, transistors, high-temperature superconducting materials;

[0030] (3) Preparing a drug delivery system for targeted therapy;

[0031] (4) Improving the photoelectric conversion efficiency of solar cells.

[0032] The method for preparing single-crystal rare-earth compound nanosheets provided by the present invention uses the chemical vapor deposition method, and utilizes rare-earth compounds as source materials and non-metal catalysts to generate single-crystal rare-earth compound nanosheets on the substrate material. Since the reaction process does not require metal catalysis and the growth method is simple, it has the potential for large-scale batch production, and thus can efficiently prepare rare-earth nanomaterials with high crystal quality and high rare-earth element concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0034] Figure 1It is the process flow diagram of the preparation method of the single-crystal rare-earth compound nanosheets provided by the present invention.

[0035] Figure 2 It is the schematic diagram of the reaction process provided by the present invention.

[0036] Figure 3 It is the optical microscope photo of the single-crystal erbium compound nanosheets provided by the present invention.

[0037] Figure 4 It is the scanning electron microscope photo of the single-crystal erbium compound nanosheets provided by the present invention.

[0038] Figure 5 It is the schematic diagram of the XRD result of the single-crystal erbium compound nanosheets provided by the present invention.

[0039] Figure 6 It is the high-resolution atomic arrangement of the single-crystal erbium compound under the transmission electron microscope provided by the present invention.

[0040] Figure 7 It is the emission spectrum of the single-crystal erbium compound nanosheets in the 1.5 μm band at room temperature provided by the present invention. Detailed implementation manners

[0041] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0042] The following combines Figure 1 to describe the preparation method of the single-crystal rare-earth compound nanosheets of the present invention.

[0043] Figure 1 It is the process flow diagram of the preparation method of the single-crystal rare-earth compound nanosheets provided by the present invention. As Figure 1 shown, the method includes the following steps:

[0044] Step S1: Place the substrate material into the reaction chamber.

[0045] In the specific implementation process, the substrate can be selected according to the properties and application requirements of the nanomaterials to be prepared. The substrate material is selected from materials such as silicon, silicon carbide, quartz, metal foil, germanium, gallium arsenide, and / or gallium nitride materials.

[0046] The reaction chamber is a reaction chamber for chemical vapor deposition. Before this step, there is also a step of pre-treating the substrate material. The pre-treatment is as follows: ultrasonically cleaning the substrate material with organic solvents (such as acetone, isopropyl alcohol) and deionized water to remove organic pollutants and impurities on the surface, drying the cleaned substrate material to remove residual moisture and solvents; and / or activating the substrate surface by means of plasma treatment, surface hydrophilic modification, physical vapor deposition or chemical pickling treatment to improve the bonding force between the substrate material and the reactants.

[0047] Step S2: The reactant gas enters the reaction chamber through the carrier gas, and the flow rate and proportion of the carrier gas are controlled; at the same time, the reaction chamber is heated, and the heating rate and temperature are controlled; the reactants include a source material and a catalyst. The source material is a rare earth element compound, and the catalyst is a non-metal catalyst; the mass ratio of the source material to the catalyst is 7:1 to 9:1.

[0048] The rare earth element compound is a compound with a high rare earth element ion content; preferably dysprosium compound, holmium compound, erbium compound, thulium compound, ytterbium compound, lutetium compound; preferably erbium compound.

[0049] The non-metal catalyst is sodium chloride NaCl, potassium chloride, and alkali metal chlorides, etc.

[0050] The non-metal catalyst is used to promote the growth of rare earth compounds. Among them, NaCl has good thermal stability and catalytic performance, can effectively promote the growth of rare earth compounds at high temperatures, and at the same time avoids the use of metal catalysts, effectively reducing the production cost.

[0051] In the specific implementation process, a suitable carrier gas and the flow rate of the carrier gas can be selected according to the reaction requirements of the rare earth compound and the non-metal catalyst.

[0052] The carrier gas is injected into the reaction chamber through a gas injection system, and the flow rate and proportion of the carrier gas are precisely controlled. The flow rate control can be achieved by a mass flow controller (MFC) to ensure that the gas ratio and concentration meet the growth requirements of the rare earth compound. The size of the gas flow will affect the pressure inside the tube and the nucleation on the substrate surface, which needs to be adjusted according to the specific situation.

[0053] Exemplarily, the carrier gas is a mixed gas of argon and hydrogen, in which the mixing ratio of argon and hydrogen is 95:5, or the carrier gas is one of argon and nitrogen; the carrier gas flow rate is 20 to 100 standard cubic centimeters per minute.

[0054] In the specific implementation process, the reaction chamber can be heated by means of resistance heating or induction heating until the temperature inside the reaction chamber reaches the preset temperature.

[0055] The range of the reaction chamber temperature can be determined according to the characteristics of the rare earth compounds and non-metallic catalysts participating in the reaction. The heating rate and temperature control are crucial for the growth quality of rare earth nanomaterials. If the growth temperature is too low, the supply of source materials cannot be guaranteed, affecting the production efficiency; if the growth temperature is too high, the environmental concentration of rare earth elements will be too high, and they cannot be fully oxidized by the atmosphere in the tube, affecting the growth process and the quality of single crystals.

[0056] By precisely controlling the temperature, gas pressure, and carrier gas flow rate in the reaction chamber, high-quality single crystal growth of rare earth compounds can be ensured.

[0057] Exemplarily, the heating rate is 18 - 21 degrees Celsius per minute, the preset temperature is 750 °C - 1000 °C; and / or the temperature is maintained for 20 - 60 minutes.

[0058] Step S3: The solid substances generated by the reaction are deposited on the surface of the substrate material to form a thin film or coating, obtaining single crystal rare earth compound nanosheets.

[0059] In some embodiments, the single crystal rare earth compound nanosheets are single crystal erbium compound nanosheets.

[0060] Single crystal rare earth compound nanosheets refer to two-dimensional layered materials composed of rare earth elements and other elements, and their thickness is usually between several atomic layers and dozens of nanometers. Since the layers of the material are connected by van der Waals forces, it provides a new idea for silicon-based heterogeneous integration. In addition, due to their unique electronic structure and quantum confinement effect, these two-dimensional materials exhibit many novel physical phenomena, such as the quantum spin Hall effect, topological insulators, superconductivity, etc.

[0061] The preparation of single crystal rare earth compound nanosheets provides an ideal platform for studying the structure-property relationship of materials. By regulating the composition, structure, and dimension of the materials, their physical and chemical properties can be systematically studied, providing theoretical guidance for the design of new functional materials.

[0062] After obtaining the single crystal rare earth compound nanosheets, it also includes the steps of cooling the temperature of the reaction chamber, discharging the remaining reactant gases and carrier gas, and transferring the grown nanomaterials from the substrate material through micro-nano transfer technology.

[0063] The cooling process is usually achieved by natural cooling or forced cooling to ensure that the single crystal rare earth compound nanosheets do not undergo structural changes during the cooling process. The remaining reaction gases are discharged from the reaction chamber through a vacuum pump to ensure the cleanliness of the inside of the reaction chamber.

[0064] Through micro-nano transfer technology, for example, dry transfer, the grown single crystal rare earth compound nanosheets are transferred from the substrate to the target substrate, and high-efficiency coupling devices that can be silicon-based integrated, such as silicon-based light sources and silicon-based optical amplifiers, can be realized.

[0065] A specific embodiment of the present invention further provides a single-crystal rare-earth compound nanosheet prepared by the above method.

[0066] In some embodiments, the single-crystal rare-earth compound nanosheet is a single-crystal erbium compound nanosheet.

[0067] Example 1

[0068] Select a silicon wafer as the substrate material.

[0069] Use organic solvents (such as acetone, isopropanol, etc.) and deionized water to ultrasonically clean the substrate material to remove surface organic pollutants and impurities. Dry the cleaned substrate material at high temperature to remove residual moisture and solvents. Then, activate the surface of the substrate material through plasma treatment or chemical treatment (such as pickling) to improve its bonding force with the nanomaterials.

[0070] Select erbium trichloride ErCl3 as the source material to provide erbium ions. Select sodium chloride NaCl as the catalyst. NaCl has good thermal stability and catalytic performance, and can effectively promote the growth of erbium compounds at high temperature, while avoiding the use of metal catalysts.

[0071] As Figure 2 shown, the reactant gas composed of erbium compound and sodium chloride in a ratio of 8:1 enters the reaction chamber through the carrier gas obtained by mixing argon and hydrogen in a ratio of 95:5, and the carrier gas flow rate is controlled at standard cubic centimeters per minute; at the same time, the reaction chamber is heated at a rate of 20 °C per minute until the reaction chamber temperature reaches 900 °C. After maintaining at this temperature for 60 minutes, the solid substances generated by the reaction are deposited on the surface of the substrate material to form a thin film or coating, and single-crystal erbium compound nanosheets are obtained.

[0072] Figure 3 shows the optical microscope photograph of the single-crystal erbium compound nanosheet provided by the present invention, Figure 4 shows the scanning electron microscope photograph of the single-crystal erbium compound nanosheet provided by the present invention. As Figure 3 、 Figure 4 shown, the single-crystal erbium compound nanosheet provided by the present invention has a regular polygonal structure consistent with the lattice structure, and the edges are very smooth, proving that its growth follows the lattice arrangement rules and has the characteristics of small volume, thin thickness, high specific surface area, etc. Therefore, the single-crystal erbium compound nanosheet provided by the present invention has a high crystal quality.

[0073] Figure 5 shows the schematic diagram of the XRD (X-ray diffraction) results of the single-crystal erbium compound nanosheet provided by the present invention. Figure 5Among them, the red curve represents the grown sample (single-crystal erbium compound nanosheets), while the black curve represents the standard diffraction data (PDF-ErOCI) of erbium oxohalide (ErOCI). By comparing the two curves, it can be observed that the positions of the diffraction peaks of the grown sample are basically the same as those of the standard peaks of PDF-ErOCI, and the main diffraction peaks appear at angles of approximately 10° and 30° respectively. This result indicates that the crystal structure of the synthesized single-crystal erbium compound nanosheets matches the known crystal structure of ErOCI, thus confirming that the sample is erbium oxohalide (for example, ErOCI). Since in erbium oxohalide, the theoretical concentration of Er particles is 1.7×10²² cm⁻³, which is 2-3 orders of magnitude higher than the concentration of erbium-doped materials. Therefore, the single-crystal erbium compound nanosheets provided by the present invention have a high erbium ion concentration, can effectively alleviate the concentration quenching phenomenon, and can provide higher gain for optoelectronic devices such as optical amplifiers and lasers. And Figure 5 Among them, the diffraction peaks are sharp and there are no impurity peaks, proving that the single-crystal erbium compound nanosheets provided by the present invention have no impurity phases and high growth purity.

[0074] Figure 6 Shows the high-resolution atomic arrangement of the single-crystal erbium compound provided by the present invention under a transmission electron microscope. As Figure 6 shown, the single-crystal erbium compound nanosheets have regular atomic arrangements, which also proves that the single-crystal erbium compound nanosheets provided by the present invention have high crystal quality.

[0075] Figure 7 Shows the emission spectrum of the single-crystal erbium compound nanosheets provided by the present invention in the 1.5-μm band at room temperature. As Figure 7 shown, the single-crystal erbium compound nanosheets provided by the present invention exhibit obvious emission peaks in the 1.5-μm band, especially at 1537 nm and 1543 nm, indicating that they have strong emission ability; the full width at half maximum of the emission peaks is narrow, 2.5 nm and 3.8 nm respectively, which helps to improve the spectral resolution and signal quality. And, even at room temperature, the single-crystal erbium compound nanosheets can maintain stable emission characteristics without the need for a special low-temperature environment, and have broad application potential.

[0076] A specific embodiment of the present invention also provides a product containing the single-crystal rare-earth compound nanosheets as described above.

[0077] The product includes optical communication devices, coupling devices, field effect transistors, photodetectors, solar cells, magnetic memories, biosensors, gas sensors, biofluorescence labeling instruments, quantum information devices, solid lighting components, lasers, amplifiers, catalysts, fuel cells or high-temperature superconducting materials, etc.

[0078] A specific embodiment of the present invention further provides the following applications of using the preparation method of the single-crystalline rare earth compound nanosheets as described above or the single-crystalline rare earth compound nanosheets as described above:

[0079] (1) Amplify optical signals.

[0080] (2) Prepare fuel cells, lasers, catalysts, detectors, magnetic memories, sensors, transistors, high-temperature superconducting materials.

[0081] (3) Prepare a drug delivery system to achieve targeted therapy.

[0082] (4) Improve the photoelectric conversion efficiency of solar cells.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a two-dimensional single crystal rare earth compound nanosheet, characterized in that: A chemical vapor deposition method is used to generate rare earth compound nanosheets on a substrate material, comprising the steps of: (1) Placing the substrate material into the reaction chamber; (2) The reactant gas enters the reaction chamber through the carrier gas, and the carrier gas flow rate and ratio are controlled; the reaction chamber is heated at the same time, and the heating rate and temperature are controlled; the reactant includes a source material and a catalyst, the source material is a rare earth element compound, and the catalyst is an alkali metal chloride; the mass ratio of the source material to the catalyst is 7:1 to 9:1; the rare earth element compound is a dysprosium compound, a holmium compound, an erbium compound, a thulium compound, a ytterbium compound, or a lutetium compound; (3) The solid substance generated by the reaction is deposited on the surface of the base material to form a thin film or coating, thereby obtaining a two-dimensional single crystal rare earth compound nanosheet.

2. The preparation method according to claim 1, characterized in that: The catalyst is sodium chloride or potassium chloride.

3. The preparation method according to claim 1 or 2, characterized in that: The substrate material in step (1) is selected from silicon, silicon carbide, quartz, metal foil, germanium, gallium arsenide and / or gallium nitride; and / or Prior to step (1), the step of pre-treating the substrate material is also included, wherein the pre-treatment comprises: ultrasonically cleaning the substrate material using an organic solvent and deionized water to remove organic pollutants and impurities on the surface, drying the cleaned substrate material to remove residual moisture and solvent; and / or activating the substrate surface by plasma treatment, surface hydrophilic modification, physical vapor deposition or chemical pickling treatment to improve the bonding strength between the substrate material and the reactant.

4. The preparation method according to claim 3, characterized in that: The carrier gas in step (2) is an argon-hydrogen mixture, wherein the mixing ratio of argon to hydrogen is 95:5; or In step (2), the carrier gas is one of argon and nitrogen; and the carrier gas flow rate is 20 to 100 standard cubic centimeters per minute.

5. The preparation method according to claim 4, characterized in that: In step (2), the heating rate is 18-21°C / min, the temperature is 750°C-1000°C; and / or the temperature is maintained for 20-60 minutes.

6. A two-dimensional single crystal rare earth compound nanosheet, prepared by the preparation method according to any one of claims 1 to 5. The two-dimensional single-crystalline rare earth compound nanosheet according to claim 6 , which is a single-crystalline erbium compound nanosheet.

8. A product containing the two-dimensional single-crystalline rare earth compound nanosheet according to claim 6 or 7; the product includes optical communication devices, coupling devices, field effect transistors, photodetectors, solar cells, magnetic storage devices, biosensors, gas sensors, bioluminescent labeling instruments, quantum information devices, solid-state lighting components, lasers, amplifiers, catalysts, fuel cells or high-temperature superconducting materials.

9. Any of the following uses of the two-dimensional single crystal rare earth compound nanosheet according to any one of claims 6-7: (1) Amplify the optical signal; (2) Preparation of fuel cells, lasers, catalysts, detectors, magnetic storage, sensors, transistors, and high-temperature superconducting materials; (3) Preparation of drug delivery systems to achieve targeted therapy; (4) Improve the photoelectric conversion efficiency of solar cells.

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