Two-dimensional atomic crystals and methods of growing the same

Abstract

The disclosure provides a two-dimensional atomic crystal and a growth method thereof. The method comprises: growing a solid source film on a first substrate; placing a second substrate on the first substrate in a heating furnace, wherein the solid source film is located between the first substrate and the second substrate; heating the heating furnace to a reaction temperature under a protective gas atmosphere, maintaining the reaction temperature for a time T, and then reducing to room temperature to grow a two-dimensional atomic crystal on the second substrate. The two-dimensional atomic crystal growth method is simple in process, and the hexagonal boron nitride two-dimensional atomic crystal lattice is single in orientation and extremely high in crystalline quality when directly grown on a dielectric substrate. The growth process is clean and environmentally friendly, has low requirements for production equipment, is low in cost, and is convenient for industrialization.

Description

Technical Field

[0001] This disclosure relates to the field of materials preparation technology, and in particular to a two-dimensional atomic crystal and its growth method. Background Technology

[0002] As research on graphene deepens, other two-dimensional atomic crystals such as hexagonal boron nitride (h-BN), transition metal dichalcogenides (TMDs), black phosphorus, silicene, and germanene are gradually coming into the view of researchers. Among them, hexagonal boron nitride, as a two-dimensional material, has an atomically flat surface, very few surface dangling bonds and trapped charges, and a low dielectric constant, making it an ideal substrate, gate dielectric, and cladding layer for other two-dimensional material devices. On the other hand, as a wide bandgap semiconductor, it has good insulation, high absorption coefficient, and high thermal conductivity. These properties make it promising for applications in high-temperature, high-frequency, high-power electronic devices and deep-ultraviolet optoelectronic devices.

[0003] Currently, substrates for growing h-BN are divided into metal substrates and dielectric substrates. Metal substrates possess catalytic properties, allowing for the formation of single crystal domains with high crystal quality. However, when h-BN covers the entire substrate, the catalytic activity of the metal is severely limited, resulting in a self-limiting effect. Therefore, h-BN grown on metal substrates is typically thin, restricting its application in high-power devices. Furthermore, h-BN grown on metal substrates needs to be transferred to a dielectric substrate before subsequent testing and device fabrication. This transfer process introduces impurities and defects, leading to a decrease in sample quality and hindering the improvement of h-BN-based device performance. Dielectric substrates, lacking catalytic activity, generally produce h-BN of lower quality. Published papers indicate that BN grown directly on dielectric substrates exhibits a larger full width at half maximum (FWHM) in its Raman spectrum compared to samples grown on metal substrates, and continuous layered structures are barely visible in HRTEM, suggesting that samples grown directly on dielectric substrates are of lower quality. Furthermore, large-area growth of h-BN on dielectric substrates typically employs MOCVD equipment, but MOCVD precursors are toxic, produce numerous byproducts, and have interdependent growth parameters that are difficult to control. Therefore, further research is needed to achieve the growth of large-area, high-quality hexagonal boron nitride two-dimensional atomic crystals. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the existing technical problems, this disclosure provides a two-dimensional atomic crystal and its growth method, which at least partially solves the above-mentioned technical problems.

[0006] (II) Technical Solution

[0007] This disclosure provides a method for growing a two-dimensional atomic crystal, comprising: growing a solid source thin film on a first substrate; stacking a second substrate and the first substrate together and placing them in a heating furnace, wherein the solid source thin film is located between the first substrate and the second substrate; heating the heating furnace to a reaction temperature under a protective gas atmosphere, maintaining the reaction temperature for a time T, and then cooling it to room temperature to grow a two-dimensional atomic crystal on the second substrate.

[0008] Optionally, the first substrate is a metal substrate or a dielectric substrate, and the second substrate is a dielectric substrate.

[0009] Alternatively, the dielectric substrate may be made of alumina or zirconium oxide.

[0010] Alternatively, the solid-state source film may be boron nitride or elemental boron.

[0011] Optionally, the boron nitride is hexagonal boron nitride.

[0012] Optionally, a solid source thin film may be grown on the first substrate using any one of physical vapor deposition, chemical vapor deposition, molecular beam epitaxy, or liquid phase deposition.

[0013] Optionally, under a protective gas atmosphere, the furnace is heated to the reaction temperature, and after maintaining the reaction temperature for a time T, it is cooled to room temperature to grow a two-dimensional atomic crystal on the second substrate. This process includes: evacuating the furnace to below 1 Pa, introducing argon or nitrogen gas at a first rate to atmospheric pressure, repeating the evacuation and protective gas introduction 4-6 times, then heating the furnace to 1350℃-1750℃ at a second rate; maintaining the gas flow rate constant and holding the reaction temperature for 0.5h-4h, then cooling to 500℃ at a third rate, and finally allowing it to cool naturally to room temperature to obtain the two-dimensional atomic crystal. The first rate is 40sccm-400sccm, the second rate is less than or equal to 5℃ / min, and the third rate is less than or equal to 3℃ / min.

[0014] Optionally, a solid source film with a thickness of 30 nm or more is grown on the first substrate.

[0015] Optionally, before growing a solid source thin film on the first substrate, the two-dimensional atomic crystal growth method further includes: ultrasonically cleaning the first substrate and the second substrate in acetone, isopropanol, ethanol and deionized water in sequence and drying them with nitrogen gas.

[0016] Another aspect of this disclosure provides a two-dimensional atomic crystal, which is prepared using the two-dimensional atomic crystal growth method of any embodiment of this disclosure.

[0017] (III) Beneficial Effects

[0018] This disclosure provides a method for growing two-dimensional atomic crystals. By stacking a dielectric substrate on another substrate containing a solid boron source on its surface, and then evaporating the solid boron source in a heated furnace, a high-quality hexagonal boron nitride two-dimensional atomic crystal can be grown on the surface of the dielectric substrate. This method is simple, directly growing high-quality hexagonal boron nitride two-dimensional atomic crystals on the dielectric substrate, reducing impurities and defects that may be introduced during the transfer process. The resulting hexagonal boron nitride two-dimensional atomic crystal has a single crystal orientation and extremely high crystal quality. The growth process is clean and environmentally friendly, requires minimal production equipment, is low-cost, and is easy to industrialize. Attached Figure Description

[0019] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0020] Figure 1 A flowchart illustrating a method for growing a two-dimensional atomic crystal according to an embodiment of the present disclosure is shown schematically.

[0021] Figure 2 A schematic diagram illustrating the structure of a two-dimensional atomic crystal growth apparatus according to an embodiment of the present disclosure is shown.

[0022] Figure 3 An SEM image of a two-dimensional atomic crystal according to an embodiment of the present disclosure is shown schematically.

[0023] Figure 4 An AFM diagram of a two-dimensional atomic crystal according to an embodiment of the present disclosure is illustrated schematically;

[0024] Figure 5 A TEM image of a two-dimensional atomic crystal according to an embodiment of the present disclosure is shown schematically.

[0025] Figure 6 The Raman spectrum of a two-dimensional atomic crystal according to an embodiment of the present disclosure is illustrated schematically.

[0026] Figure 7 The XRD pattern of a two-dimensional atomic crystal according to an embodiment of the present disclosure is illustrated schematically.

[0027] Figure 8 The Raman spectrum of a two-dimensional atomic crystal according to another embodiment of the present disclosure is schematically shown;

[0028] Figure 9 The Raman spectrum of a two-dimensional atomic crystal according to yet another embodiment of the present disclosure is schematically shown;

[0029] Figure 10 The Raman spectrum of a two-dimensional atomic crystal according to yet another embodiment of the present disclosure is schematically shown.

[0030] [Explanation of Labels in the Attached Image]

[0031] 1-Protective gas source

[0032] 2-First substrate

[0033] 3-Solid-state source thin film

[0034] 4-Second substrate

[0035] 5-Heating Furnace

[0036] 6-Vacuum Pump

[0037] 7- Vent valve

[0038] 8-Platinum Protective Layer

[0039] 9-h-BN two-dimensional atomic crystal Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0041] It should be noted that similar or identical parts are referred to by the same reference numerals in the accompanying drawings or description. The technical features of the various embodiments exemplified in the specification can be freely combined to form new solutions without conflict. Furthermore, each claim can stand alone as an embodiment, or the technical features in the various claims can be combined to form new embodiments. In the drawings, the shape or thickness of the embodiments may be enlarged and indicated in a simplified or convenient manner. Moreover, elements or implementations not shown or described in the drawings are those known to those skilled in the art. Additionally, although this document provides examples of parameters containing specific values, it should be understood that the parameters need not be exactly equal to the corresponding values, but can approximate the corresponding values ​​within acceptable error tolerances or design constraints.

[0042] Unless there are technical obstacles or contradictions, the various embodiments described above in this disclosure can be freely combined to form other embodiments, all of which are within the protection scope of this disclosure.

[0043] Although this disclosure has been described in conjunction with the accompanying drawings, the embodiments disclosed in the drawings are intended to illustrate preferred embodiments of this disclosure and should not be construed as limiting the disclosure. The dimensions in the drawings are merely illustrative and should not be construed as limiting the disclosure.

[0044] While some embodiments of the general concept of this disclosure have been shown and described, those skilled in the art will understand that changes may be made to these embodiments without departing from the principles and spirit of the general concept of this disclosure, the scope of which is defined by the claims and their equivalents.

[0045] Figure 1 A flowchart illustrating a method for growing a two-dimensional atomic crystal according to an embodiment of the present disclosure is shown.

[0046] According to embodiments of this disclosure, such as Figure 1 As shown, methods for growing two-dimensional atomic crystals include, for example:

[0047] S110, a solid source thin film is grown on the first substrate.

[0048] According to embodiments of this disclosure, to ensure the cleanliness of the relevant substrates and avoid introducing impurities, a step S100 can be added before step S110, in which the first substrate and the second substrate are sequentially ultrasonically cleaned in acetone, isopropanol, ethanol, and deionized water and then dried with nitrogen gas to obtain clean first and second substrates. The first substrate is a carrier for providing a solid source (e.g., hexagonal boron nitride), and can be a metal substrate or a dielectric substrate. The metal substrate can be, for example, Cu, Ni, Pt, etc., and the dielectric substrate can be, for example, alumina (e.g., sapphire) or zirconium oxide, etc. The second substrate is a carrier for growing two-dimensional atomic crystals. One of the purposes of this disclosure is to directly grow two-dimensional atomic crystals on a dielectric substrate to avoid introducing impurities by transferring the two-dimensional atomic crystal to the substrate. Therefore, the second substrate is, for example, a dielectric substrate.

[0049] According to embodiments of this disclosure, after obtaining a clean dielectric substrate, a hexagonal boron nitride (h-BN) or B thin film is grown on the dielectric substrate, for example, by physical or chemical deposition methods. These physical or chemical deposition methods include, but are not limited to, physical vapor deposition, chemical vapor deposition, molecular beam epitaxy, and liquid phase deposition. The thickness of the h-BN or B thin film grown on the dielectric substrate is, for example, not less than 30 nm, serving as a solid-state source to provide the raw materials required for growing two-dimensional atomic crystals on another clean substrate (i.e., the second substrate).

[0050] S120, the second substrate and the first substrate are stacked and placed in a heating furnace, wherein the solid source film is located between the first substrate and the second substrate.

[0051] Figure 2 A schematic diagram of a structure for a two-dimensional atomic crystal growth apparatus according to an embodiment of the present disclosure is shown.

[0052] According to embodiments of this disclosure, a blank clean dielectric substrate (i.e., the second substrate) is stacked face-to-face with a solid-state source on the first substrate and then placed in a heating furnace, such as a tube furnace. Figure 2 As shown, the two-dimensional atomic crystal growth apparatus includes, for example, a protective gas source 1, a heating furnace 5, and a vacuum pump 6. A first substrate 2 and a second substrate 4, stacked together, are placed in the furnace chamber of the heating furnace 5. A solid source thin film 3 is grown on the first substrate 2 and located between the first substrate 2 and the second substrate 4. Figure 2 The relative positions of the first substrate 2 and the second substrate 4 are only schematic. The first substrate can also be stacked on the second substrate 4, or other arrangements. As long as the two are stacked, the solid source film 3 is located between the first substrate 2 and the second substrate 4.

[0053] It is understandable that, in order to improve the growth quality of the two-dimensional atomic crystal on the second substrate 4, the second substrate 4 and the first substrate 2 can be bonded as tightly as possible. For example, they can be placed in a crucible and pressed tightly by the pressure of the crucible lid to form a relatively stable reaction space, thereby reducing the evaporation of the solid source and the influence of airflow disturbance on the condensation and deposition on the second substrate 4, so as to obtain a high-quality hexagonal boron nitride two-dimensional atomic crystal.

[0054] S130, under a protective gas atmosphere, the furnace is heated to the reaction temperature, held at the reaction temperature for a time T, and then cooled to room temperature to grow a two-dimensional atomic crystal on the second substrate.

[0055] According to embodiments of this disclosure, a protective gas atmosphere is formed in a tube furnace, for example, by evacuating and then introducing a protective gas. Specifically, the operation involves: using a vacuum pump to evacuate the pressure inside the tube furnace to below 1 Pa, then turning off the vacuum pump and introducing argon or nitrogen to atmospheric pressure. This evacuation is repeated 4-6 times to remove other gaseous impurities from the furnace tube, ensuring both substrates are in a high-purity protective gas atmosphere. The flow rate of argon or nitrogen is, for example, 40-400 sccm. Maintaining a constant flow rate, the tube furnace is heated to the reaction temperature at a rate, for example, no greater than 5°C / min. The reaction temperature range is, for example, 1350-1750°C. Then, maintaining a constant reaction temperature, the solid source evaporates and continuously adsorbs onto the surface of the second substrate, or reacts with nitrogen and then adsorbs onto the surface of the second substrate. The reaction temperature is maintained for, for example, 0.5-4 hours, allowing the two-dimensional atomic crystal growth surface of the second substrate to fully adsorb boron nitride gas and ensuring the growth surface of the two-dimensional atomic crystal is in a high-concentration boron nitride gas atmosphere. Subsequently, the tube furnace is cooled from the reaction temperature to 500°C at a rate not exceeding 3°C / min, allowing hexagonal boron nitride two-dimensional atomic crystals to slowly condense and deposit (crystallize) on the two-dimensional atomic crystal growth surface of the second substrate. Finally, it is naturally cooled to room temperature, completing the direct growth of high-quality hexagonal boron nitride two-dimensional atomic crystals on the dielectric substrate. Compared to technologies such as MBE, the two-dimensional atomic crystal growth method disclosed herein does not require the provision of toxic precursors, the growth process is clean and environmentally friendly, the growth process is simple and easy to operate, there are no other toxic byproducts, no toxic or harmful exhaust gases, and high-quality hexagonal boron nitride two-dimensional atomic crystals can be directly grown on the dielectric substrate without complex chemical reactions, laying the foundation for the further application of high-quality hexagonal boron nitride two-dimensional atomic crystals.

[0056] The two-dimensional atomic crystal growth method of this disclosure will be described in detail below with reference to specific embodiments.

[0057] Example 1

[0058] First, a 2-inch sapphire substrate was ultrasonically cleaned sequentially in acetone, isopropanol, ethanol, and deionized water for 20 minutes each, and then dried with a nitrogen gun. An h-BN thin film, approximately 100 nm thick, was grown on the sapphire substrate as a solid-state source using pulsed laser deposition. Another blank sapphire substrate was stacked face-to-face on top of the h-BN solid-state source, and this stack was placed in a tube furnace. The pressure inside the tube furnace was evacuated to below 1 Pa from one end using a vacuum pump. Then, the vacuum pump was turned off, and argon gas was introduced from the other end of the tube furnace to raise the pressure to atmospheric pressure. After repeating this evacuation and purging process 4-6 times, the temperature of the tube furnace was raised to 1600 °C in stages at a heating rate of no more than 5 °C / min under an argon gas flow of 400 sccm, and held at 1600 °C for 1 hour. Then, the temperature was lowered to 500 °C in stages at a rate of no more than 3 °C / min, and finally allowed to cool naturally to room temperature. This resulted in a high-quality hexagonal boron nitride two-dimensional atomic crystal on the blank sapphire substrate.

[0059] Figure 3 An SEM image of a two-dimensional atomic crystal according to an embodiment of the present disclosure is shown schematically.

[0060] Figure 4 An AFM diagram of a two-dimensional atomic crystal according to an embodiment of the present disclosure is shown schematically.

[0061] According to embodiments of this disclosure, the surface morphology of the hexagonal boron nitride two-dimensional atomic crystal sample obtained in Example 1 above was tested. Please refer to [link to relevant documentation]. Figure 3 and Figure 4 The images shown are typical SEM (scanning electron microscope) and AFM (atomic force microscope) images of the h-BN two-dimensional atomic crystal grown on a sapphire substrate in Example 1 above. Analysis combining the SEM and AFM images revealed that the surface roughness of the sample is approximately 1 nm. This indicates that the hexagonal boron nitride two-dimensional atomic crystal grown using the method provided in this disclosure exhibits very small surface undulations and good uniformity.

[0062] Figure 5 A schematic TEM image of a two-dimensional atomic crystal according to an embodiment of the present disclosure is shown.

[0063] According to embodiments of this disclosure, in order to further analyze the crystallinity of the sample obtained in Example 1 above, cross-sectional high-resolution TEM (Transmission Electron Microscope) testing was performed on it. Please refer to [link to relevant documentation]. Figure 5Before TEM sample preparation, a platinum protective layer is required. The resulting layered sample includes, for example, a platinum protective layer 8, an h-BN two-dimensional atomic crystal 9, and a second substrate 4. Figure 5 As can be seen, approximately 10 layers of hexagonal boron nitride two-dimensional atomic crystals, about 3.5 nm thick, were obtained on the sapphire substrate (i.e., the second substrate 4). Cross-sectional TEM analysis shows that the hexagonal boron nitride two-dimensional atomic crystal sample grown by the method disclosed in this paper exhibits a distinct layered structure and high crystal quality. By controlling the growth conditions, the growth thickness of the hexagonal boron nitride two-dimensional atomic crystal can be obtained, for example, between 3 nm and 100 nm.

[0064] Figure 6 The Raman spectrum of a two-dimensional atomic crystal according to an embodiment of the present disclosure is schematically shown.

[0065] According to embodiments of this disclosure, from Figure 6 The sample can be seen to be 1366.62 cm. -1 There is a characteristic peak at that point, corresponding to the E of h-BN. 2g The vibrational mode has a full width at half maximum (FWHM) of 13.1 cm. -1 The full width at half maximum (FWHM) of the Raman characteristic peaks is comparable to that of the h-BN sample grown on a metal substrate, indicating that the two-dimensional atomic crystal sample grown in Example 1 of this disclosure has extremely high crystallinity and does not require a transfer process, reducing the introduction of impurities and defects and further ensuring the high crystallinity of the sample.

[0066] Figure 7 The XRD pattern of a two-dimensional atomic crystal according to an embodiment of the present disclosure is illustrated schematically.

[0067] According to embodiments of this disclosure, in order to further determine the lattice orientation of the sample obtained on the sapphire substrate in Embodiment 1 above, XRD (diffraction of x-rays) tests were performed on it. Please refer to [link to relevant documentation]. Figure 7 The diffraction peak at 26.7° corresponds to the (002) plane of h-BN, and the diffraction peak at 55.1° corresponds to the (004) plane of h-BN. No other peaks appear. The half-width at half-maximum (WHM) of the characteristic peak at the (002) plane is 0.43°. XRD test results show that the hexagonal boron nitride two-dimensional atomic crystal grown on the sapphire substrate provided in this disclosure has a high-quality single lattice orientation, which is beneficial to the further application of hexagonal boron nitride.

[0068] Example 2

[0069] First, a 2-inch sapphire substrate was ultrasonically cleaned sequentially in acetone, isopropanol, ethanol, and deionized water for 20 minutes each, and then dried with a nitrogen gun. An h-BN thin film, approximately 40 nm thick, was grown on the sapphire substrate as a solid-state source using pulsed laser deposition. Another blank zirconia substrate was stacked face-to-face on the h-BN solid-state source, and this stack was placed in a tube furnace. The pressure inside the tube furnace was evacuated to below 1 Pa from one end using a vacuum pump. Then, the vacuum pump was turned off, and nitrogen gas was introduced from the other end of the tube furnace to raise the pressure to atmospheric pressure. This evacuation and purging process was repeated 4-6 times. The temperature of the tube furnace was then raised to 1350 °C in stages at a nitrogen flow rate of no more than 5 °C / min, under a nitrogen flow of 200 sccm, and held at 1350 °C for 4 hours. The temperature was then lowered to 500 °C in stages at a rate of no more than 3 °C / min, and finally allowed to cool naturally to room temperature. High-quality hexagonal boron nitride two-dimensional atomic crystals were finally grown on the blank zirconia substrate.

[0070] Figure 8 The Raman spectrum of a two-dimensional atomic crystal according to another embodiment of the present disclosure is schematically shown.

[0071] According to embodiments of this disclosure, the Raman spectrum of the hexagonal boron nitride two-dimensional atomic crystal sample grown in Example 2 above is as follows: Figure 8 As shown, the characteristic peak of this h-BN two-dimensional atomic crystal is located at 1368.71 cm⁻¹. -1 The peak half-height and width are 17.5cm. -1 It can be seen that the hexagonal boron nitride two-dimensional atomic crystal sample obtained on the zirconium oxide substrate in this embodiment has extremely high crystal quality, which provides a strong guarantee for its further application.

[0072] Example 3

[0073] First, a 2-inch sapphire substrate was ultrasonically cleaned sequentially in acetone, isopropanol, ethanol, and deionized water for 20 minutes each, and then dried with a nitrogen gun. An h-BN thin film with a thickness of approximately 200 nm was grown on the sapphire substrate as a solid-state source using pulsed laser deposition. Another blank sapphire substrate was stacked face-to-face on the h-BN solid-state source, and this stacked structure was placed in a tube furnace. The pressure inside the tube furnace was evacuated to below 1 Pa from one end using a vacuum pump. Then, the vacuum pump was turned off, and argon gas was introduced from the other end of the tube furnace to raise the pressure to atmospheric pressure. After repeating this evacuation and purging process 4-6 times, the temperature of the tube furnace was raised to 1750 °C in stages at a heating rate of no more than 5 °C / min under an argon gas flow of 100 sccm, and held at 1750 °C for 0.5 h. Then, the temperature was lowered to 500 °C in stages at a rate of no more than 3 °C / min, and allowed to cool naturally to room temperature. Finally, a high-quality hexagonal boron nitride two-dimensional atomic crystal was obtained on the blank sapphire substrate.

[0074] Figure 9 The Raman spectrum of a two-dimensional atomic crystal according to yet another embodiment of the present disclosure is schematically shown.

[0075] According to embodiments of this disclosure, the Raman spectrum of the hexagonal boron nitride two-dimensional atomic crystal sample grown in Example 3 above is as follows: Figure 9 As shown, the characteristic peak of this h-BN two-dimensional atomic crystal is located at 1367.45 cm⁻¹. -1 The peak half-height and width are 12.5cm. -1 It can be seen that the hexagonal boron nitride two-dimensional atomic crystal sample obtained on the sapphire substrate in this embodiment also has extremely high crystal quality.

[0076] Example 4

[0077] First, a 2-inch sapphire substrate was ultrasonically cleaned sequentially in acetone, isopropanol, ethanol, and deionized water for 20 minutes each, and then dried with a nitrogen gun. A boron (B) thin film, approximately 50 nm thick, was grown on the sapphire substrate as a solid-state source using pulsed laser deposition. Another blank sapphire substrate was stacked face-to-face on the B solid-state source, and this stack was placed in a tube furnace. The pressure inside the tube furnace was evacuated to below 1 Pa from one end using a vacuum pump. Then, the vacuum pump was turned off, and nitrogen gas was introduced from the other end of the tube furnace to raise the pressure to atmospheric pressure. This evacuation and purging process was repeated 4-6 times. The temperature was then raised to 1600 °C in stages at a nitrogen flow rate of no more than 5 °C / min, under a nitrogen flow of 400 sccm, and held at 1600 °C for 1 hour. The temperature was then lowered to 500 °C in stages at a rate of no more than 3 °C / min, and allowed to cool naturally to room temperature. Finally, a high-quality hexagonal boron nitride two-dimensional atomic crystal was obtained on the blank sapphire substrate.

[0078] Figure 10 The Raman spectrum of a two-dimensional atomic crystal according to yet another embodiment of the present disclosure is schematically shown.

[0079] According to embodiments of this disclosure, the Raman spectrum of the hexagonal boron nitride two-dimensional atomic crystal sample grown in Example 4 above is as follows: Figure 10 As shown, the characteristic peak of this h-BN two-dimensional atomic crystal is located at 1366.92 cm⁻¹. -1 The peak half-height and width are 9.8cm. -1 It can be seen that the hexagonal boron nitride two-dimensional atomic crystal sample obtained on the sapphire substrate in this embodiment also has extremely high crystal quality.

[0080] In summary, this disclosure presents a method for growing two-dimensional atomic crystals. By stacking a dielectric substrate on another substrate containing a solid boron source on its surface, and then evaporating the solid boron source in a heating furnace, a high-quality hexagonal boron nitride two-dimensional atomic crystal can be grown on the surface of the dielectric substrate. This method is simple, produces hexagonal boron nitride two-dimensional atomic crystals with a single lattice orientation and extremely high crystal quality. The growth process is clean and environmentally friendly, requires minimal production equipment, is low-cost, and facilitates industrial-scale application.

[0081] In another aspect, this disclosure provides a two-dimensional atomic crystal, which is prepared using the two-dimensional atomic crystal growth method of any of the above embodiments of this disclosure.

[0082] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to a specific order or hierarchy.

[0083] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of this disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted when they may cause confusion in understanding this disclosure. Furthermore, the shapes, sizes, and positional relationships of the components in the drawings do not reflect their actual size, scale, or actual positional relationships.

[0084] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, this disclosure is in a state of having fewer features than all of the features of the single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, with each claim representing a separate preferred embodiment of this disclosure.

[0085] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified. The term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," as "including" is used as a conjunction in the claims. The use of any term "or" in the specification or claims is intended to mean "non-exclusive or."

[0086] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A method for growing a two-dimensional atomic crystal, comprising: A solid source thin film is grown on a first substrate, wherein the first substrate is a metal substrate or a dielectric substrate, and the solid source thin film is hexagonal boron nitride or elemental boron. The second substrate is stacked with the first substrate and then placed in a heating furnace, wherein the solid source film is located between the first substrate and the second substrate, and the second substrate is a dielectric substrate; Under a protective gas atmosphere, the furnace is heated to the reaction temperature, held at the reaction temperature for a time T, and then cooled to room temperature to grow a two-dimensional hexagonal boron nitride atomic crystal on the second substrate. When the solid source film is hexagonal boron nitride, the protective gas atmosphere is nitrogen or argon. When the solid source film is elemental boron, the protective gas atmosphere is nitrogen.

2. The two-dimensional atomic crystal growth method according to claim 1, wherein the solid source film is grown on the first substrate using any one of physical vapor deposition, chemical vapor deposition, molecular beam epitaxy, or liquid phase deposition.

3. The two-dimensional atomic crystal growth method according to claim 1, wherein heating the furnace to the reaction temperature under a protective gas atmosphere, maintaining the reaction temperature for a time T, and then cooling to room temperature to grow the two-dimensional atomic crystal on the second substrate comprises: The heating furnace is evacuated to below 1 Pa, and argon or nitrogen is introduced at a first rate to atmospheric pressure. After repeating the evacuation and protective gas introduction 4-6 times, the heating furnace is heated to 1350℃-1750℃ at a second rate. With the ventilation rate kept constant, the reaction temperature was maintained for 0.5h-4h, and then cooled to 500℃ at a third rate, followed by natural cooling to room temperature to obtain the two-dimensional atomic crystal. The first rate is 40 sccm-400 sccm, the second rate is less than or equal to 5 ℃ / min, and the third rate is less than or equal to 3 ℃ / min.

4. The two-dimensional atomic crystal growth method according to claim 1, wherein a solid source thin film with a thickness greater than or equal to 30 nm is grown on the first substrate.

5. The two-dimensional atomic crystal growth method according to claim 1, wherein before growing the solid source film on the first substrate, the two-dimensional atomic crystal growth method further comprises: The first substrate and the second substrate were sequentially ultrasonically cleaned in acetone, isopropanol, ethanol and deionized water and then dried with nitrogen gas.

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