A method for preparing two-dimensional TMDCs by surfactant-assisted molten salt CVD
Patent Information
- Application Number
- CN202610804867.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-05
- Publication Date
- 2026-09-08
AI Technical Summary
[0006]现有熔盐CVD方法在生长二维TMDCs过程中，旋涂负载于生长衬底表面的含熔盐前驱体液滴容易出现分布不均和局部堆积现象，进而导致覆盖率不足、多层生长以及晶界缺陷等问题，限制了二维TMDCs的大面积高质量制备
[0024] This invention significantly reduces the surface tension of precursor droplets by adding surfactants (SDS and/or Triton X-100) to the molten salt precursor solution, thereby improving its wettability with the growth substrate (such as sapphire, silicon oxide/silicon). This results in uniformly sized and densely distributed molten salt precursor particles after spin coating and baking, avoiding localized accumulation and droplet agglomeration.
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Abstract
Description
Technical Field
[0001] This invention relates to a method for preparing two-dimensional TMDCs (Transition Metal Dichalcogenides) by surfactant-assisted molten salt CVD (Chemical Vapor Deposition), belonging to the field of two-dimensional semiconductor material preparation technology. Background Technology
[0002] Since the successful preparation of graphene, two-dimensional TMDCs, such as MoS2 and WSe2, with atomic-level thickness and excellent electrical and optical properties, have attracted widespread attention and are considered important candidate materials for next-generation semiconductor electronic devices. Currently, the main methods for preparing two-dimensional TMDCs include mechanical exfoliation, liquid-phase exfoliation, physical vapor deposition (PVD), and CVD. Among these, CVD is considered an important technical route for achieving large-area, controllable preparation of two-dimensional TMDCs due to its better controllability and higher yield. However, when using conventional CVD methods to prepare two-dimensional TMDCs, problems remain, such as the difficulty in further improving the monolayer coverage and the difficulty in effectively suppressing vertical multilayer growth.
[0003] In recent years, molten salt CVD has attracted widespread attention due to its ability to improve the controllability of two-dimensional TMDC growth processes, based on a vapor-liquid-solid (VLS) growth mechanism. Molten salt CVD refers to the direct growth of two-dimensional TMDCs on the growth substrate surface of a molten, non-volatile molten salt precursor via a VLS mechanism after reacting with sulfur or selenium vapor. To achieve molten salt CVD growth, the molten salt precursor typically needs to have a suitable melting point, be able to form a stable melt with low vapor pressure at the growth temperature, and be soluble in water to facilitate the preparation of the precursor solution and its loading onto the substrate surface. Molten salt CVD typically achieves large-area TMDC growth by increasing the domain size and promoting the splicing of adjacent domains. While existing molten salt CVD methods can increase the domain size of individual TMDCs at lower temperatures, thereby improving material coverage to some extent, achieving high coverage and high monolayer percentage in the growth of TMDCs remains a significant challenge.
[0004] Furthermore, during molten salt CVD growth, uneven droplet distribution and localized accumulation often occur after the precursor solution is loaded onto the substrate surface. This leads to localized overfeeding during subsequent growth, resulting in problems such as multilayer growth, increased grain boundary defects, and insufficient film continuity, which limits its application in large-area devices. Surfactants can reduce liquid surface tension, improve droplet wetting behavior on the substrate surface, and enhance droplet distribution uniformity. However, current technologies lack systematic applications that introduce surfactants into the molten salt precursor system to improve the precursor distribution during molten salt CVD growth and enhance the growth quality of two-dimensional TMDCs. Summary of the Invention
[0005] Technical issues:
[0006] In existing molten salt CVD methods for growing two-dimensional metamorphic digital structures (TMDCs), the molten salt-containing precursor droplets spin-coated onto the growth substrate surface are prone to uneven distribution and localized accumulation, leading to insufficient coverage, multilayer growth, and grain boundary defects, thus limiting the large-area, high-quality fabrication of TMDCs. The purpose of this invention is to provide a surfactant-assisted molten salt CVD method for preparing 2D TMDCs. By introducing a surfactant into the molten salt precursor solution, the wettability between the precursor droplets and the growth substrate during spin-coating is improved, and the uniformity of the molten salt-containing precursor droplet distribution is enhanced, reducing localized precursor accumulation. This, in turn, improves the single-layer coverage and overall growth quality of molten salt CVD-grown 2D TMDCs.
[0007] Technical solution:
[0008] To address the aforementioned technical problems, this invention provides a method for preparing two-dimensional TMDCs using a surfactant-assisted molten salt CVD method, comprising the following steps:
[0009] (1) Dissolve the molten salt precursor in water to obtain a precursor solution, wherein the molten salt precursor is at least one of Na2MoO4 and Na2WO4;
[0010] (2) A surfactant is added to the precursor solution to obtain a mixed solution, wherein the surfactant is at least one of sodium dodecyl sulfate (SDS) and Triton X-100;
[0011] (3) Load the mixed solution onto the surface of the growth substrate;
[0012] (4) The growth substrate loaded with the mixed solution is baked to remove moisture and fix the position of the molten salt precursor particles.
[0013] (5) Place the baked growth substrate in a reaction furnace, and introduce a sulfur source or selenium source at a reaction temperature of 700℃~1000℃ under an inert or reducing atmosphere, so that the molten salt precursor undergoes a chemical reaction on the surface of the growth substrate to form two-dimensional transition metal chalcogenides (TMDCs).
[0014] Preferably, the amount of surfactant added is 0.001% to 5% of the total mass of the precursor solution.
[0015] Preferably, the growth substrate is a sapphire substrate or a silicon oxide / silicon substrate.
[0016] Preferably, in step (3), the mixed solution is loaded onto the surface of the growth substrate by spin coating.
[0017] Preferably, the inert atmosphere in step (5) is argon, and the reducing atmosphere is a mixture of argon and hydrogen.
[0018] Preferably, the sulfur source in step (5) is one or more of elemental sulfur, inorganic sulfur-containing compounds, or organic sulfur-containing compounds that can provide active sulfur species under growth conditions; the selenium source is one or more of elemental selenium, inorganic selenium-containing compounds, or organic selenium-containing compounds that can provide active selenium species under growth conditions.
[0019] More preferably, the sulfur source is solid sulfur, and the selenium source is solid selenium.
[0020] Preferably, the two-dimensional transition metal chalcogenide is at least one of MoS2, MoSe2, WS2 and WSe2.
[0021] Preferably, in step (5), a dual-temperature zone tube furnace is used, in which the sulfur source or selenium source is placed in the first temperature zone and the growth substrate is placed in the second temperature zone. Gaseous sulfur or gaseous selenium is transported to the second temperature zone to participate in the reaction through a carrier gas.
[0022] The present invention also provides a two-dimensional transition metal chalcogenide prepared by the above method.
[0023] Beneficial effects:
[0024] This invention significantly reduces the surface tension of precursor droplets by adding surfactants (SDS and / or Triton X-100) to the molten salt precursor solution, thereby improving its wettability with the growth substrate (such as sapphire, silicon oxide / silicon). This results in uniformly sized and densely distributed molten salt precursor particles after spin coating and baking, avoiding localized accumulation and droplet agglomeration.
[0025] Uniformly distributed precursor particles can react synchronously and splice well during subsequent CVD growth to form a continuous monolayer film. Examples show that the addition of surfactants significantly improves the monolayer coverage of MoS2 and WSe2, and significantly reduces multilayer stacking at grain boundaries, which can be essentially eliminated under certain conditions.
[0026] The amount of surfactant added is extremely small (0.001% to 5% by mass), and there is no need to change the original molten salt CVD equipment and main process parameters, making it easy to promote.
[0027] The method of this invention is applicable to the growth of various two-dimensional TMDCs (MoS2, MoSe2, WS2, WSe2) and is effective on various substrates such as sapphire and silicon oxide / silicon, and has good versatility. Attached Figure Description
[0028] Figure 1 Schematic diagram of molten salt CVD process: In the first temperature zone, solid S or Se is heated until it becomes gaseous S or Se. The carrier gas transports the gaseous S or Se to the second temperature zone, where it reacts chemically with the Na2MoO4 or Na2WO4 molten salt on the surface of the sapphire substrate to generate the corresponding TMDCs material.
[0029] Figure 2 (a) SEM image of the distribution of Na2MoO4 molten salt particles after spin-coating a pure Na2MoO4 solution onto a sapphire surface and baking; (b) SEM image of the distribution of Na2MoO4 molten salt particles after spin-coating a mixed solution of Na2MoO4 and SDS onto a sapphire surface and baking; (c) SEM image of the distribution of Na2MoO4 molten salt particles after spin-coating a mixed solution of Na2MoO4 and Triton X-100 onto a sapphire surface and baking; (a), (b), and (c) demonstrate that the Na2MoO4 molten salt precursor particles are more uniform in size and more densely distributed after adding SDS or Triton X-100.
[0030] Figure 3 Comparison of MoS2 growth by molten salt CVD method: For the same concentration of Na2MoO4, (a) after adding SDS, a continuous monolayer MoS2 film can be obtained; (b) without adding SDS, only a low coverage of MoS2 can be obtained.
[0031] Figure 4 Comparison of MoS2 growth by molten salt CVD: For the same concentration of Na2MoO4, (a) adding Triton X-100 can obtain a continuous monolayer MoS2 film; (b) without adding Triton X-100, only a low coverage of MoS2 can be obtained.
[0032] Figure 5 Comparison of WSe2 growth by molten salt CVD: For the same concentration of Na2WO4, (a) adding SDS can obtain a continuous monolayer WSe2 film; (b) without adding SDS, only WSe2 with a lower coverage can be obtained.
[0033] Figure 6 Comparison of WSe2 growth by molten salt CVD: For the same concentration of Na2WO4, (a) with the addition of Triton X-100, a continuous monolayer WSe2 film can be obtained with almost no multilayer WSe2 at the grain boundaries; (b) without the addition of Triton X-100, although a high coverage WSe2 film is also obtained, a large number of multilayer WSe2 appear at the grain boundaries. Detailed Implementation
[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments. The following embodiments use solid sulfur and solid selenium as specific examples of sulfur / selenium sources, but the present invention is not limited thereto; other sulfur / selenium-containing compounds that can provide active sulfur / selenium species under growth conditions may also be applied.
[0035] Example 1: Preparation of MoS2 crystals by SDS-assisted molten salt CVD
[0036] (1) Substrate treatment:
[0037] Sapphire substrate was used as the growth substrate. First, the surface of the sapphire substrate was cleaned with nitrogen gas, and then it was cleaned with oxygen plasma to obtain a hydrophilic sapphire substrate.
[0038] (2) Solution spin coating and baking treatment:
[0039] A mixed solution containing Na₂MoO₄ and SDS was prepared, with Na₂MoO₄ concentrations of 14 mM / L and SDS concentrations of 0.1 mM / L. The mixed solution was spin-coated onto the surface of a pre-treated sapphire substrate at 6000 rpm for 30 s. Subsequently, the spin-coated sapphire substrate was placed on a heating stage for baking to remove surface moisture, fix the position of the Na₂MoO₄ molten salt particles, and inhibit the agglomeration of Na₂MoO₄ droplets within a short period. After the addition of SDS, the distribution of Na₂MoO₄ molten salt particles on the sapphire surface was as follows: Figure 2 As shown in (b), the particle size difference is small and the distribution is relatively uniform; without the addition of SDS, the distribution of Na2MoO4 molten salt particles is as follows. Figure 2 As shown in (a), the particle size difference is obvious and the distribution is uneven.
[0040] (3) Dual-temperature zone heating growth:
[0041] Solid sulfur was placed in the first temperature zone of a dual-temperature tube furnace, and the sapphire substrate treated in step (2) was placed in the second temperature zone of the tube furnace. The first temperature zone was heated to 160 ℃ at a heating rate of 40 ℃ / min, and the second temperature zone was heated to 760 ℃ at a heating rate of 20 ℃ / min. Under an argon protective atmosphere, the solid sulfur in the first temperature zone melted and volatilized, and was then transported to the second temperature zone to react chemically with Na2MoO4 on the surface of the sapphire substrate to form MoS2.
[0042] (4) Result characterization:
[0043] Figure 3 Image (a) shows the optical image of MoS2 prepared in this embodiment. The results indicate that the obtained sample essentially forms a continuous monolayer of MoS2 within the field of view, with only a small amount of multilayer MoS2 present. Compared to the sample without SDS... Figure 3 Compared to (b), the addition of SDS significantly improved the monolayer coverage of the MoS2 film, and the crystal domains were able to be well spliced together.
[0044] Example 2: Preparation of MoS2 crystals by Triton X-100-assisted molten salt CVD
[0045] (1) Substrate treatment:
[0046] Sapphire substrate was used as the growth substrate. First, the surface of the sapphire substrate was cleaned with nitrogen gas, and then it was cleaned with oxygen plasma to obtain a hydrophilic sapphire substrate.
[0047] (2) Solution spin coating and baking treatment:
[0048] A mixed solution containing Na₂MoO₄ and Triton X-100 was prepared, wherein the concentration of Na₂MoO₄ was 13 mM / L and the mass fraction of Triton X-100 in the entire precursor mixture was 0.05%. The mixed solution was spin-coated onto the surface of a pre-treated sapphire substrate at 10,000 rpm for 30 s. Subsequently, the spin-coated sapphire substrate was placed on a heating stage for baking to remove moisture from the substrate surface, fix the position of the Na₂MoO₄ molten salt particles, and inhibit the agglomeration of Na₂MoO₄ droplets in a short period. After the addition of Triton X-100, the distribution of Na₂MoO₄ molten salt particles on the sapphire surface was as follows. Figure 2 As shown in (c), the particle size difference is small and the distribution is relatively uniform; without the addition of Triton X-100, the distribution of Na2MoO4 molten salt particles is as follows. Figure 2 As shown in (a), the particle size difference is obvious and the distribution is uneven.
[0049] (3) Dual-temperature zone heating growth:
[0050] Solid sulfur was placed in the first temperature zone of a dual-temperature zone tube furnace, and the sapphire substrate treated in step (2) was placed in the second temperature zone of the tube furnace. The first temperature zone was heated to 180 ℃ at a heating rate of 40 ℃ / min, and the second temperature zone was heated to 760 ℃ at a heating rate of 20 ℃ / min. Under an argon protective atmosphere, the solid sulfur in the first temperature zone melted and volatilized, and was then transported to the second temperature zone to react chemically with Na2MoO4 on the surface of the sapphire substrate to form MoS2.
[0051] (4) Result characterization:
[0052] Figure 4 Image (a) shows the optical image of MoS2 prepared in this embodiment. The results indicate that the obtained sample essentially forms a continuous monolayer of MoS2 within the field of view, with only a small amount of multilayer MoS2 present. This is in contrast to the sample without Triton X-100. Figure 4 Compared to (b), under the same Na2MoO4 concentration, the addition of Triton X-100 resulted in a continuous monolayer MoS2 film, while the absence of Triton X-100 resulted in only a MoS2 film with a lower coverage.
[0053] Example 3: Preparation of WSe2 crystals by SDS-assisted molten salt CVD
[0054] (1) Substrate treatment:
[0055] Sapphire substrate was used as the growth substrate. First, the surface of the sapphire substrate was cleaned with nitrogen gas, and then it was cleaned with oxygen plasma to obtain a hydrophilic sapphire substrate.
[0056] (2) Solution spin coating and baking treatment:
[0057] A mixed solution containing Na₂WO₄ and SDS was prepared, with Na₂WO₄ concentrations of 16 mM / L and SDS concentrations of 0.1 mM / L. The mixed solution was spin-coated onto the surface of a pre-treated sapphire substrate at 8000 rpm for 30 s. Subsequently, the spin-coated sapphire substrate was placed on a heating stage for baking to remove surface moisture, fix the position of the Na₂WO₄ molten salt particles, and inhibit the agglomeration of Na₂WO₄ droplets within a short period. The distribution of Na₂WO₄ molten salt particles on the sapphire substrate surface after the addition of SDS can be referenced. Figure 2 The distribution characteristics of the molten salt particles shown in (b) are that the particle size difference is small and the distribution is relatively uniform.
[0058] (3) Dual-temperature zone heating growth:
[0059] Solid selenium was placed in the first temperature zone of a dual-temperature zone tube furnace, and the sapphire substrate treated in step (2) was placed in the second temperature zone of the tube furnace. The first temperature zone was heated to 325 ℃ at a heating rate of 40 ℃ / min, and the second temperature zone was heated to 825 ℃ at a heating rate of 20 ℃ / min. Under the protective atmosphere of argon-hydrogen mixture, the solid selenium in the first temperature zone melted and volatilized, and was then transported to the second temperature zone, where it reacted chemically with Na2WO4 on the surface of the sapphire substrate and hydrogen in the tube to form WSe2.
[0060] (4) Result characterization:
[0061] Figure 5 Image (a) shows the optical image of WSe2 prepared in this embodiment. The results indicate that individual WSe2 domains can be spliced together to form a continuous thin film, and only a very small amount of multilayered WSe2 exists at the grain boundaries. Compared with film without SDS... Figure 5 Compared to (b) (single-layer coverage less than 70%), under the same Na2WO4 concentration, the addition of SDS resulted in a continuous single-layer WSe2 film, while without the addition of SDS, only a low coverage WSe2 film was obtained.
[0062] Example 4: Preparation of WSe2 crystals by Triton X-100-assisted molten salt CVD
[0063] (1) Substrate treatment:
[0064] Sapphire substrate was used as the growth substrate. First, the surface of the sapphire substrate was cleaned with nitrogen gas, and then it was cleaned with oxygen plasma to obtain a hydrophilic sapphire substrate.
[0065] (2) Solution spin coating and baking treatment:
[0066] A mixed solution containing Na₂WO₄ and Triton X-100 was prepared, wherein the concentration of Na₂WO₄ was 16 mM / L and the mass fraction of Triton X-100 in the entire precursor mixture was 0.1%. The mixed solution was spin-coated onto the surface of a pre-treated sapphire substrate at 6000 rpm for 30 s. Subsequently, the spin-coated sapphire substrate was placed on a heating stage for baking to remove moisture from the substrate surface, fix the position of the Na₂WO₄ molten salt particles, and inhibit the agglomeration of Na₂WO₄ droplets within a short period. The distribution of Na₂WO₄ molten salt particles on the sapphire substrate surface after the addition of Triton X-100 can be referenced. Figure 2 The distribution characteristics of Na2MoO4 molten salt particles shown in (c) are that the particle size difference is small and the distribution is relatively uniform.
[0067] (3) Dual-temperature zone heating growth:
[0068] Solid selenium was placed in the first temperature zone of a dual-temperature zone tube furnace, and the sapphire substrate treated in step (2) was placed in the second temperature zone of the tube furnace. The first temperature zone was heated to 325 ℃ at a heating rate of 40 ℃ / min, and the second temperature zone was heated to 825 ℃ at a heating rate of 20 ℃ / min. Under the protective atmosphere of argon-hydrogen mixture, the solid selenium in the first temperature zone melted and volatilized, and was then transported to the second temperature zone, where it reacted chemically with Na2WO4 on the surface of the sapphire substrate and hydrogen in the tube to form WSe2.
[0069] (4) Result characterization:
[0070] Figure 6 Image (a) shows the optical image of WSe2 prepared in this embodiment. The results indicate that individual WSe2 domains can be spliced together to form a continuous thin film, and only a very small amount of multilayered WSe2 exists at the grain boundaries. This is in contrast to the film without Triton X-100. Figure 6 Compared to (b) (which has a high coverage but a large number of multilayer WSe2 at the grain boundaries), under the same Na2WO4 concentration, adding Triton X-100 can obtain a film with continuous single-layer coverage and almost no multilayer WSe2 at the grain boundaries. However, without the addition of Triton X-100, although a film with a high coverage of WSe2 can also be obtained, a large number of multilayer WSe2 will appear at the grain boundaries.
[0071] Example 5: Preparation of MoS2 crystals by molten salt CVD without SDS
[0072] A Na₂MoO₄ solution with a concentration of 14 mM / L was used as the molten salt precursor solution, and no SDS was added. The remaining substrate treatment, solution loading, baking treatment, and dual-temperature zone heating growth conditions were the same as in Example 1.
[0073] Figure 3 Image (b) shows the optical image of MoS2 prepared in this embodiment. The results show that the obtained sample exhibits significant multilayer stacking at the grain boundaries, and a small amount of multilayer MoS2 also appears in the central region of the grain domains. Furthermore, the grain domains failed to successfully splice together to form a continuous film. Compared with Example 1, it can be seen that the introduction of SDS is beneficial to improving the coverage of monolayer MoS2 and reducing multilayer stacking at the grain boundaries.
[0074] Example 6: Preparation of MoS2 crystals by molten salt CVD without the addition of Triton X-100
[0075] A Na₂MoO₄ solution was used as the molten salt precursor solution, with a Na₂MoO₄ concentration of 13 mM / L, and Triton X-100 was not added. The remaining substrate treatment, solution loading, baking treatment, and dual-temperature zone heating growth conditions were the same as in Example 2.
[0076] Figure 4 Image (b) shows the optical image of MoS2 prepared in this embodiment. The results indicate that a small amount of multilayer MoS2 appears in the central region of the crystal domains of the obtained sample, and the crystal domains failed to successfully splice together to form a continuous film. Compared with Example 2, it can be seen that the introduction of Triton X-100 is beneficial to improving the coverage of monolayer MoS2.
[0077] Example 7: Preparation of WSe2 crystals by molten salt CVD without SDS
[0078] A Na₂WO₄ solution was used as the molten salt precursor solution, with a Na₂WO₄ concentration of 16 mM / L, and no SDS was added. The remaining substrate treatment, solution loading, baking treatment, and dual-temperature zone heating growth conditions were the same as in Example 3.
[0079] Figure 5 Image (b) shows the WSe2 optical image prepared in this embodiment. The results show that the single-layer coverage of WSe2 is less than 70%. Compared with Example 3, it can be seen that the introduction of SDS is beneficial to improving the single-layer coverage of WSe2.
[0080] Example 8: Preparation of WSe2 crystals by molten salt CVD without the addition of Triton X-100
[0081] A Na₂WO₄ solution was used as the molten salt precursor solution, with a Na₂WO₄ concentration of 16 mM / L, and Triton X-100 was not added. The remaining substrate treatment, solution loading, baking treatment, and dual-temperature zone heating growth conditions were the same as in Example 4.
[0082] Figure 6 Image (b) shows the optical image of WSe2 prepared in this embodiment. The results show that although individual WSe2 domains can be spliced together to form a continuous thin film, a large number of multilayer WSe2 layers appear at the grain boundaries. Compared with Example 4, it can be seen that the introduction of Triton X-100 is beneficial to reduce the multilayer accumulation of WSe2 at the grain boundaries.
Claims
1. A method for preparing two-dimensional TMDCs by surfactant-assisted molten salt CVD, characterized in that, Includes the following steps: (1) Dissolve the molten salt precursor in water to obtain a precursor solution, wherein the molten salt precursor is at least one of Na2MoO4 and Na2WO4; (2) A surfactant is added to the precursor solution to obtain a mixed solution, wherein the surfactant is at least one of sodium dodecyl sulfate (SDS) and Triton X-100; (3) Load the mixed solution onto the surface of the growth substrate; (4) The growth substrate loaded with the mixed solution is baked to remove moisture and fix the position of the molten salt precursor particles. (5) Place the baked growth substrate in a reaction furnace, and introduce a sulfur source or selenium source at the reaction temperature under an inert or reducing atmosphere to allow the molten salt precursor to undergo a chemical reaction on the surface of the growth substrate to form two-dimensional transition metal chalcogenides (TMDCs).
2. The method according to claim 1, characterized in that, The amount of surfactant added is 0.001% to 5% of the total mass of the precursor solution.
3. The method according to claim 1, characterized in that, The growth substrate is a sapphire substrate or a silicon oxide / silicon substrate.
4. The method according to claim 1, characterized in that, In step (3), the mixed solution is loaded onto the surface of the growth substrate by spin coating.
5. The method according to claim 1, characterized in that, The inert atmosphere in step (5) is argon, and the reducing atmosphere is a mixture of argon and hydrogen.
6. The method according to claim 1, characterized in that, The sulfur source in step (5) is one or more of elemental sulfur, inorganic sulfur-containing compounds, or organic sulfur-containing compounds that can provide active sulfur species under growth conditions; the selenium source is one or more of elemental selenium, inorganic selenium-containing compounds, or organic selenium-containing compounds that can provide active selenium species under growth conditions.
7. The method according to claim 6, characterized in that, The sulfur source is solid sulfur, and the selenium source is solid selenium.
8. The method according to claim 1, characterized in that, The two-dimensional transition metal chalcogenide is at least one of MoS2, MoSe2, WS2 and WSe2.
9. The method according to claim 1, characterized in that, In step (5), a dual-temperature zone tube furnace is used. The sulfur source or selenium source is placed in the first temperature zone, and the growth substrate is placed in the second temperature zone. Gaseous sulfur or gaseous selenium is transported to the second temperature zone to participate in the reaction through a carrier gas.
10. A two-dimensional transition metal chalcogenide prepared by the method according to any one of claims 1 to 9.