Preparation method of high-quality hexagonal boron nitride film with economy and environmental friendliness

Abstract

The present application relates to the hexagonal boron nitride film preparation field, concretely to an economic, environment-friendly high-quality hexagonal boron nitride film preparation method, which is suitable for the large-scale preparation of high-quality hexagonal boron nitride film. The method uses nitrogen-containing gas as the nitrogen source, provides boron source through the high-defect boron nitride material, and places the high-defect boron nitride material and the substrate in the high-temperature zone. The nitrogen atoms generated by the high-temperature cracking of the nitrogen-containing precursor react with the boron atoms generated by the high-defect boron nitride to grow the hexagonal boron nitride film on the substrate surface. By changing the type of growth substrate, growth temperature and time, the thickness, grain size and crystallinity of the hexagonal boron nitride film can be controlled. The preparation process of the present application is simple and easy to scale up, and can batch produce large-size high-quality hexagonal boron nitride film. The present application lays the foundation for the application of ultra-thin / atomic-level thickness hexagonal boron nitride film in electronic devices, corrosion and oxidation resistant coatings, thermal management and ion transport fields.

Description

Technical fields:

[0001] This invention relates to the field of hexagonal boron nitride thin film preparation, specifically to an economical and environmentally friendly method for preparing high-quality hexagonal boron nitride thin films, suitable for large-scale preparation of high-quality hexagonal boron nitride thin films. Background technology:

[0002] Hexagonal boron nitride, due to its graphite-like crystal structure, is known as "white graphite" and is composed of strongly polar boron-nitrogen bonds. It has a high melting point of 3000℃, is resistant to high temperatures, corrosion, and oxidation, and also possesses electrical insulation, high thermal conductivity, and good lubricity. Therefore, it is widely used in refractory materials, high-temperature lubricants, and mold release agents. Hexagonal boron nitride's excellent radiation resistance and neutron absorption properties make it suitable for use as a structural material in nuclear reactors and as a neutron shielding material.

[0003] Two-dimensional hexagonal boron nitride, as one of the most widely studied two-dimensional layered materials besides graphene, has broad application prospects in deep ultraviolet detection, encapsulation layers, gate insulating layers, thermal management, high-temperature oxidation and corrosion resistant protective layers, and proton transport due to its wide bandgap (~6.0 eV), atomically flat surface, high thermal conductivity, high mechanical strength and excellent thermal stability.

[0004] The preparation of hexagonal boron nitride (HNB) thin films is crucial to their applications. However, because HNB is composed of only boron and nitrogen, its chemical preparation process is more difficult to control compared to that of elemental graphene. Currently, methods for preparing HNB thin films include chemical vapor deposition (CVD), magnetron sputtering, molecular beam epitaxy (MBE), and metal-organic vapor deposition (MOV). Overall, CVD is widely used due to its advantages such as precise control over the number of layers, simple operation, low equipment cost, and ease of obtaining large-size, high-quality films. However, the mainstream CVD method for preparing two-dimensional HNB thin films currently uses expensive and toxic precursors such as ammonia borane to provide the boron and nitrogen sources, resulting in high preparation costs, environmental unfriendliness, and safety hazards. Other CVD methods, such as those using boron oxide and ammonia as raw materials, and transition metal borides (which also serve as substrates) and nitrogen as raw materials, generally suffer from poor control over the number of film layers, complex preparation methods, and difficulty in scale-up. Therefore, there is an urgent need to develop a low-cost, safe, environmentally friendly, and controllable method for the large-scale preparation of high-quality hexagonal boron nitride thin films. Summary of the Invention:

[0005] The purpose of this invention is to provide an economical and environmentally friendly method for preparing high-quality hexagonal boron nitride thin films, which solves the problems of high cost, high toxicity, and poor controllability of current chemical vapor deposition methods, and provides a material basis for studying the intrinsic properties of hexagonal boron nitride thin films and realizing their large-scale application.

[0006] The technical solution of this invention is:

[0007] An economical and environmentally friendly method for preparing high-quality hexagonal boron nitride thin films is disclosed. The method uses nitrogen, ammonia, urea vapor, or a mixture thereof as the nitrogen source and provides the boron source through a boron nitride material with high surface defects. The boron source is placed together with the substrate in a high-temperature zone. The nitrogen atoms generated by the high-temperature cracking of nitrogen, ammonia, or urea vapor react with the boron atoms generated by the boron nitride material with high surface defects, thereby growing a hexagonal boron nitride thin film on the substrate surface.

[0008] The method for preparing the economical and environmentally friendly high-quality hexagonal boron nitride thin film, wherein the boron nitride material is hexagonal boron nitride (h-BN), rhombohedral boron nitride (r-BN), cubic boron nitride (c-BN) or wurtzite boron nitride (w-BN) according to its crystal structure, and the boron nitride material is in the form of tubular, plate, porous foam, nanosheet or powder, or a combination of two or more of these.

[0009] The method for preparing the economical and environmentally friendly high-quality hexagonal boron nitride thin film uses a substrate that is one or more alloy substrates selected from copper, nickel, gold, platinum, iron, and cobalt with high catalytic activity, or a substrate that is one or more non-metallic substrates selected from sapphire, silicon wafer, mica, and quartz.

[0010] The method for preparing high-quality hexagonal boron nitride thin films that is economical and environmentally friendly involves using a carrier gas that is a mixture of inert gas and hydrogen or pure hydrogen. The inert gas is one or more of helium, neon, and argon, and the inert gas and hydrogen are used in any volume ratio; or, no carrier gas is required.

[0011] The method for preparing high-quality hexagonal boron nitride thin films that are economical and environmentally friendly involves treating boron nitride material at 800–1050°C for 5 hours to 1 minute in an air or oxygen atmosphere, or by high-energy ball milling for 1–12 hours, or by plasma treatment with one or more of hydrogen, oxygen, and nitrogen to obtain boron nitride material with high surface defects. The boron nitride material with high surface defects is located upstream or below the growth substrate in a horizontal quartz tube. The horizontal quartz tube is inserted into the inner cavity of a heating furnace for heating. The growth temperature of the hexagonal boron nitride thin film is not lower than 600°C and does not exceed the boiling point of the substrate. The growth time is 1 minute to 24 hours.

[0012] The economical and environmentally friendly method for preparing high-quality hexagonal boron nitride thin films obtained by this method determines the maximum size of the hexagonal boron nitride thin film by the size of the substrate.

[0013] The method for preparing high-quality hexagonal boron nitride thin films that is economical and environmentally friendly can control the thickness, grain size and crystallinity of the hexagonal boron nitride thin films by changing the type of growth substrate, growth temperature and time.

[0014] The method for preparing the economical and environmentally friendly high-quality hexagonal boron nitride thin film has the following technical parameters: thickness range of 0.4 nm to 10 μm, and grain size of 100 nm to 1 m.

[0015] The method for preparing high-quality hexagonal boron nitride thin films that are economical and environmentally friendly involves using an etching method or an electrochemical bubbling method to separate the hexagonal boron nitride thin film grown on the substrate surface from the growth substrate surface; or, the hexagonal boron nitride thin film is used together with the growth substrate.

[0016] The method described above is an economical and environmentally friendly method for preparing high-quality hexagonal boron nitride thin films. The hexagonal boron nitride thin films have excellent crystallinity and can be used as ultra-thin / atomic-level thickness hexagonal boron nitride thin films in electronic devices, anti-corrosion and anti-oxidation coatings, thermal management, and ion transport fields.

[0017] The design principle of this invention is:

[0018] This invention uses solid boron nitride material with high surface defects as the boron source. The boron source is slowly released through high-temperature hydrogen etching. A metal or non-metal substrate and the boron nitride material with high defects are placed together in a furnace and heated to the reaction temperature. Nitrogen, ammonia, and urea vapors are introduced and decomposed at high temperature to release nitrogen atoms. The nitrogen atoms react with the boron atoms decomposed from the high-defect parts of the boron nitride material on the substrate surface to form hexagonal boron nitride crystal nuclei. As the growth time increases, the crystal nuclei density increases. Due to the continuous supply of nitrogen, ammonia, urea vapor, or a mixture of gases in any proportion and the continuous decomposition of the boron nitride with high surface defects, the crystal nuclei also grow. When the growth time is long enough, the hexagonal boron nitride domains assemble into a complete thin film, thereby achieving the controllable, low-cost, safe, and environmentally friendly large-scale preparation of high-quality hexagonal boron nitride thin films.

[0019] The advantages and beneficial effects of this invention are:

[0020] 1. This invention proposes a novel, economical, and environmentally friendly method for preparing high-quality hexagonal boron nitride thin films. The growth of hexagonal boron nitride thin films is well controllable, and the boron source is a cheap and readily available boron nitride material with high surface defects. It has the advantages of simple process, low equipment requirements, convenient operation, low cost, easy performance control, and safety and environmental protection.

[0021] 2. This invention can control the growth rate and thickness of hexagonal boron nitride films by adjusting the degree of oxidation on the surface of the hexagonal boron nitride material.

[0022] 3. The hexagonal boron nitride obtained by this invention has a thickness of 0.4 nm to 10 μm and a grain size of 10 nm to 1 m. The morphology and size depend on the shape and size of the substrate used. Attached image description:

[0023] Figure 1 Schematic diagram of an experimental setup for growing hexagonal boron nitride thin films using the CVD method. In the diagram, 1 is the gas inlet; 2 is the quartz tube; 3 is the boron nitride substrate with high surface defects; 4 is the growth substrate; 5 is the heating furnace; and 6 is the gas outlet.

[0024] Figure 2 Figure a shows an optical microscope image of a single-layer hexagonal boron nitride crystal grown on a copper foil substrate for 0.5 hours. Figure b shows an optical microscope image of a hexagonal boron nitride thin film grown on a copper foil substrate for 2 hours.

[0025] Figure 3 Figure a shows an optical microscope image of a single hexagonal boron nitride crystal transferred from a copper foil substrate to a SiO2 / Si substrate after 0.5 hours of growth. Figure b shows an atomic force microscope image of a single hexagonal boron nitride crystal transferred from a copper foil substrate to a SiO2 / Si substrate after 0.5 hours of growth (the inset shows the boron nitride height curve).

[0026] Figure 4 Figures a and b show the XPS spectra of Bs1 and Ns1 hexagonal boron nitride grown on copper, respectively. In the figures, the horizontal axis represents the binding energy (eV), and the vertical axis represents the relative intensity (au).

[0027] Figure 5 Figure a shows the transmission electron microscope image of the single-layer hexagonal boron nitride film grown on copper foil transferred to a microgrid; Figure b shows the corresponding selected electron diffraction pattern in Figure a.

[0028] Figure 6 Raman spectra of a single hexagonal boron nitride crystal transferred to a SiO2 / Si substrate after 1 hour of growth on a copper foil substrate; in the figure, the horizontal axis Raman Shift represents the Raman shift (cm). -1 The vertical axis Intensity represents the relative intensity (au).

[0029] Figure 7 A 2-inch hexagonal boron nitride film was transferred onto a 4-foot SiO2 / Si wafer. Detailed implementation method:

[0030] In the specific implementation process, the present invention first places the growth substrate and the boron nitride plate with high surface defects together in a quartz tube and heats it to a predetermined temperature under a reducing atmosphere. Then, a certain flow rate of nitrogen, ammonia, urea vapor or a mixture of gases in any proportion is introduced to carry out the reaction. Hexagonal boron nitride nucleates and grows on the surface of the growth substrate and finally forms a film. Hexagonal boron nitride can be transferred to the target substrate or used directly on the growth substrate.

[0031] The present invention will now be described in further detail with reference to embodiments and accompanying drawings.

[0032] Example 1

[0033] First, such as Figure 1 As shown, this invention uses a horizontal heating furnace to grow a single-layer hexagonal boron nitride thin film. A horizontal quartz tube 2, inserted within the furnace 5, has a gas inlet 1 and a gas outlet 6 at both ends. A boron nitride substrate (20mm × 10mm × 2mm) is treated in air at 1000℃ for 2 hours to form a boron nitride substrate 3 with high surface defects. A copper foil substrate 4 (25μm thick, 99.5wt% purity) of the same dimensions is then stacked with the boron nitride substrate 3 with a 1mm gap, placed in the central region of the quartz tube 2. The temperature is raised to 1050℃ in a hydrogen atmosphere of 200 sccm, followed by the introduction of ammonia gas at 5 sccm for reaction. After 1 hour of growth, the copper foil and boron nitride substrate are removed from the high-temperature zone and cooled to room temperature, thus obtaining a single-layer hexagonal boron nitride crystal on the copper foil. The crystal is then transferred to a target substrate by etching the copper substrate, allowing for detailed structural characterization.

[0034] Using an optical microscope ( Figure 2 Atomic force microscope (AFM) Figure 3 X-ray photoelectron spectroscopy (XPS) Figure 4 ), transmission electron microscope ( Figure 5 ) and Raman spectrometer ( Figure 6 The uniformity, number of layers, and domain size of the hexagonal boron nitride thin film were characterized, showing that the obtained hexagonal boron nitride domains were monolayers with an average thickness of 0.4 nm and an average domain size of 60 μm, and the crystal quality within the domains was good.

[0035] Example 2

[0036] First, such as Figure 1 As shown, this invention uses a horizontal heating furnace to grow a single-layer hexagonal boron nitride thin film. A horizontal quartz tube 2, inserted within the heating furnace 5, has a gas inlet 1 and a gas outlet 6 at both ends. A boron nitride substrate (20mm × 10mm × 2mm) is treated in air at 1000°C for 2 hours to form a boron nitride substrate 3 with high surface defects. A nickel foil substrate 4 (25mm thick, 99.5wt% purity) of the same dimensions is then stacked with the boron nitride substrate 3 with a 1mm gap, placed in the central region of the quartz tube 2. The temperature is raised to 1080°C in a hydrogen atmosphere of 200 sccm, followed by a nitrogen gas flow of 5 sccm for reaction. After 2 hours of growth, the nickel foil and boron nitride substrate are removed from the high-temperature zone and cooled to room temperature, thus obtaining a few-layer hexagonal boron nitride thin film on the nickel foil. The film can then be transferred to a target substrate by etching the nickel substrate, allowing for detailed structural characterization.

[0037] The uniformity, number of layers, and domain size of the hexagonal boron nitride thin film were characterized using optical microscopy, atomic force microscopy, and Raman spectroscopy. The results showed that the obtained hexagonal boron nitride thin film was a few-layer film with an average thickness of 1.2 nm and an average domain size of 20 μm, and the crystal quality within the domains was good.

[0038] Example 3

[0039] First, such as Figure 1 As shown, this invention uses a horizontal heating furnace to grow a single-layer hexagonal boron nitride thin film. A horizontal quartz tube 2, inserted within the furnace 5, has a gas inlet 1 and a gas outlet 6 at both ends. A boron nitride substrate (20mm × 10mm × 2mm) is treated in air at 1000℃ for 2 hours to form a boron nitride substrate 3 with high surface defects. A gold foil growth substrate 4 (100μm thick, 99.5wt% purity) of the same dimensions is then stacked with the boron nitride substrate 3 with a 1mm gap, placed in the central region of the quartz tube 2. The temperature is raised to 1030℃ in a hydrogen atmosphere of 200 sccm, followed by a nitrogen gas flow of 5 sccm for reaction. After 2 hours of growth, the gold foil and boron nitride substrate are removed from the high-temperature zone and cooled to room temperature, thus obtaining a single-layer hexagonal boron nitride thin film on the gold foil. This film can then be transferred to a target substrate via electrochemical bubbling for detailed structural characterization.

[0040] The uniformity, number of layers, and domain size of the hexagonal boron nitride thin film were characterized using optical microscopy, atomic force microscopy, and Raman spectroscopy. The results showed that the obtained hexagonal boron nitride thin film was a monolayer film with an average thickness of 0.4 nm and an average domain size of 50 μm, and the crystal quality within the domains was good.

[0041] Example 4

[0042] First, such as Figure 1 As shown, this invention uses a horizontal heating furnace to grow a single-layer hexagonal boron nitride thin film. A horizontal quartz tube 2, inserted within the furnace 5, has a gas inlet 1 and a gas outlet 6 at both ends. A boron nitride substrate (20mm × 10mm × 2mm) is treated in air at 1000°C for 2 hours to form a boron nitride substrate 3 with high surface defects. A platinum foil substrate 4 (150μm thick, 99.5wt% purity) of the same dimensions is then stacked with the boron nitride substrate 3 with a 1mm gap, placed in the central region of the quartz tube 2. The temperature is raised to 1100°C in a hydrogen atmosphere of 200 sccm, followed by the introduction of ammonia gas at 5 sccm for reaction. After 2 hours of growth, the platinum foil and boron nitride substrate are removed from the high-temperature zone and cooled to room temperature, thus obtaining a single-layer hexagonal boron nitride thin film on the platinum foil. This film is then transferred to a target substrate via electrochemical bubbling for detailed structural characterization.

[0043] The uniformity, number of layers, and domain size of the hexagonal boron nitride thin film were characterized using optical microscopy, atomic force microscopy, and Raman spectroscopy. The results showed that the obtained hexagonal boron nitride thin film was a monolayer film with an average thickness of 0.4 nm and an average domain size of 100 μm, and the crystal quality within the domains was good.

[0044] Example 5

[0045] First, such as Figure 1 As shown, this invention uses a horizontal heating furnace to grow a single-layer hexagonal boron nitride thin film. A horizontal quartz tube 2, inserted within the furnace 5, has a gas inlet 1 and a gas outlet 6 at both ends. A boron nitride substrate (20mm × 10mm × 2mm) is treated at 1000℃ for 2 hours in air to form a boron nitride substrate 3 with high surface defects. A mica growth substrate 4 (0.5mm thick, 99.5wt% purity) of the same dimensions is then stacked with the boron nitride substrate 3 with a 1mm gap, placed in the central region of the quartz tube 2. The temperature is raised to 1300℃ in a hydrogen atmosphere of 200 sccm, followed by the introduction of 5 sccm of ammonia gas for reaction. After 2 hours of growth, the mica and boron nitride substrate are removed from the high-temperature zone and cooled to room temperature, thus obtaining a single-layer hexagonal boron nitride thin film on a platinum foil. This film can then be transferred to a target substrate via electrochemical bubbling for detailed structural characterization.

[0046] The uniformity, number of layers, and domain size of the hexagonal boron nitride thin film were characterized using optical microscopy, atomic force microscopy, and Raman spectroscopy. The results showed that the obtained hexagonal boron nitride thin film was a monolayer film with an average thickness of 0.4 nm and an average domain size of 100 μm, and the crystal quality within the domains was good.

[0047] Example 6

[0048] First, such as Figure 1 As shown, this invention uses a horizontal heating furnace to grow a single-layer hexagonal boron nitride thin film. A horizontal quartz tube 2, inserted within the heating furnace 5, has a gas inlet 1 and a gas outlet 6 at both ends. Hexagonal boron nitride powder (400 mesh, 99.5% purity) is treated at 1000°C for 2 hours in air to form boron nitride powder with high surface defects. A copper foil substrate (25 μm thick, 99.5 wt% purity, 100 mm × 100 mm) is placed above a quartz boat containing the high-defect boron nitride powder, spaced 1 mm apart, in the central region of the quartz tube 2. The temperature is raised to 1000°C in a hydrogen atmosphere of 200 sccm, followed by the introduction of ammonia gas at 5 sccm for reaction. After 2 hours of growth, the copper foil and boron nitride substrate are removed from the high-temperature zone and cooled to room temperature, thus obtaining a complete single-layer hexagonal boron nitride thin film on the copper foil. This film can be transferred to a target substrate by electrochemical bubbling or etching for detailed structural characterization. Figure 7As shown, hexagonal boron nitride films can reach a size of 2 inches.

[0049] The uniformity, number of layers, and domain size of the hexagonal boron nitride thin film were characterized using optical microscopy, atomic force microscopy, and Raman spectroscopy. The results showed that the obtained hexagonal boron nitride thin film was a monolayer film with an average thickness of 0.4 nm and an average domain size of 100 μm, and the crystal quality within the domains was good.

[0050] Example 7

[0051] First, such as Figure 1 As shown, this invention uses a horizontal heating furnace to grow a single-layer hexagonal boron nitride thin film. A horizontal quartz tube 2, inserted within the heating furnace 5, has a gas inlet 1 and a gas outlet 6 at both ends. A boron nitride tube (R20mm×50mm, purity 99.5%) is treated at 1000℃ for 2 hours in air to form a boron nitride tube with high surface defects. A copper foil substrate (thickness 25μm, purity 99.5wt%, 20mm×20mm) is then placed in the center of the high-defect boron nitride tube and within the central region of the quartz tube 2. The temperature is raised to 1000℃ in a hydrogen atmosphere of 100 sccm, followed by the introduction of a 1:1 mixture of nitrogen and ammonia gas at 5 sccm for reaction. After 2 hours of growth, the copper foil and boron nitride tube are removed from the high-temperature zone and cooled to room temperature, resulting in a complete few-layer hexagonal boron nitride thin film on the copper foil. This film can then be transferred to a target substrate via electrochemical bubbling or etching for detailed structural characterization.

[0052] The uniformity, number of layers, and domain size of the hexagonal boron nitride thin film were characterized using optical microscopy, atomic force microscopy, and Raman spectroscopy. The results showed that the obtained hexagonal boron nitride thin film was a monolayer film with an average thickness of 1.5 nm and an average domain size of 10 μm, and the crystal quality within the domains was good.

[0053] like Figure 1 As shown, the experimental apparatus for growing high-quality hexagonal boron nitride thin films by CVD of the present invention mainly includes a gas inlet 1, a quartz tube 2, a boron nitride plate with high surface defects 3, a growth substrate 4, a heating furnace 5, and a gas outlet 6. The horizontal quartz tube 2 is inserted into the inner cavity of the heating furnace 5. The boron nitride plate with high surface defects 3 and the growth substrate 4 are stacked one on top of the other inside the quartz tube 2 with a spacing of 1 mm. The carrier gas enters the quartz tube 2 of the heating furnace 5 from the gas inlet 1 and exits from the gas outlet 6.

[0054] like Figure 2 As shown, this preparation method yields a single-layer hexagonal boron nitride crystal and a complete thin film on copper.

[0055] like Figure 3As shown, the single-layer hexagonal boron nitride crystal on copper obtained by this preparation method can be completely transferred to the SiO2 / Si substrate. The transferred film has uniform optical contrast and consistent thickness.

[0056] like Figure 4 As shown, XPS results indicate that the hexagonal boron nitride film obtained by this method is composed of N and B in a ratio close to 1:1.

[0057] like Figure 5 As shown, transmission electron microscopy results indicate that the monolayer hexagonal boron nitride film obtained by this method is a high-quality crystal.

[0058] like Figure 6 As shown, Raman spectroscopy results indicate that the monolayer hexagonal boron nitride film obtained by this method has typical Raman characteristic peaks of hexagonal boron nitride and is of uniform quality.

[0059] like Figure 7 As shown, a rectangular hexagonal boron nitride thin film with a diagonal length of 2 inches is placed on a 4-inch SiO2 / Si wafer.

[0060] The above results demonstrate that this invention uses nitrogen, ammonia, urea vapor, or a mixture of gases in any proportion as the nitrogen source, and provides the boron source through a boron nitride material with high surface defects. This boron source is placed together with a substrate such as copper in a high-temperature zone. Nitrogen atoms generated from the high-temperature decomposition of nitrogen, ammonia, or urea vapor react with boron atoms generated from the boron nitride material with high surface defects, growing a hexagonal boron nitride thin film on the substrate surface. By changing the type of substrate and growth parameters, hexagonal boron nitride thin films of different thicknesses and grain sizes can be obtained. This invention features a simple preparation process, low cost, good controllability, and a non-toxic, environmentally friendly boron source. It enables the mass production of large-size, high-quality hexagonal boron nitride thin films, laying the foundation for the application of ultrathin / atomic-level thickness hexagonal boron nitride thin films in electronic devices, anti-corrosion and anti-oxidation coatings, thermal management, and ion transport.

[0061] The embodiments provided above are merely illustrative and should not be considered as limiting the scope of the present invention. Any method that makes equivalent substitutions or changes to the technical solutions and inventive concepts of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a high-quality hexagonal boron nitride thin film, characterized in that, Using nitrogen, ammonia, urea vapor or a mixture thereof as the nitrogen source and hydrogen as the carrier gas, a boron source is provided by a boron nitride material with high surface defects. The boron source is placed together with the substrate in a high-temperature zone with a 1 mm gap between the substrate and the boron nitride material with high surface defects. Nitrogen atoms generated by high-temperature cracking of nitrogen, ammonia or urea vapor react with boron atoms generated by the boron nitride material with high surface defects to grow a hexagonal boron nitride film on the substrate surface. Boron nitride material is treated at 800~1050℃ in air or oxygen atmosphere for 2 to 5 hours to obtain boron nitride material with high surface defects. The boron nitride material with high surface defects is located upstream or below the growth substrate in a horizontal quartz tube. The horizontal quartz tube is inserted into the inner cavity of the heating furnace for heating. The growth temperature of the hexagonal boron nitride film is not lower than 600℃ and does not exceed the boiling point of the substrate. The growth time is 1 minute to 24 hours.

2. The method for preparing a high-quality hexagonal boron nitride thin film according to claim 1, characterized in that, Boron nitride materials are classified by crystal structure as hexagonal boron nitride (h-BN), rhombohedral boron nitride (r-BN), cubic boron nitride (c-BN), or wurtzite boron nitride (w-BN). Boron nitride materials are classified by morphology as tubular, plate, porous foam, nanosheet, or powder, or as one or more combinations thereof.

3. The method for preparing a high-quality hexagonal boron nitride thin film according to claim 1, characterized in that, The substrate is one or more alloy substrates of copper, nickel, gold, platinum, iron, and cobalt with high catalytic activity, or one or more non-metallic substrates of sapphire, silicon wafer, mica, and quartz.

4. The method for preparing a high-quality hexagonal boron nitride thin film according to claim 1, characterized in that, The maximum size of the obtained hexagonal boron nitride thin film is determined by the size of the substrate.

5. The method for preparing a high-quality hexagonal boron nitride thin film according to claim 1, characterized in that, By changing the type of growth substrate, growth temperature, and time, the thickness, grain size, and crystallinity of hexagonal boron nitride films can be controlled.

6. The method for preparing a high-quality hexagonal boron nitride thin film according to claim 5, characterized in that, The technical parameters for hexagonal boron nitride thin films are: thickness range of 0.4 nm to 10 μm.

7. The method for preparing a high-quality hexagonal boron nitride thin film according to claim 1, characterized in that, The hexagonal boron nitride film grown on the substrate surface is separated from the substrate surface by etching or electrochemical bubbling; or the hexagonal boron nitride film is used together with the substrate.

8. The method for preparing a high-quality hexagonal boron nitride thin film according to claim 1, characterized in that, Hexagonal boron nitride thin films are used in electronic devices, corrosion and oxidation protection coatings, thermal management, and ion transport.

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