A method for preparing a molybdenum disulfide film

Abstract

The application discloses a preparation method of a molybdenum disulfide film and relates to the technical field of film growth. The preparation method of the molybdenum disulfide film comprises the following steps: S100, providing a substrate and placing the substrate in a reaction cavity; S200, alternately feeding a molybdenum source and a sulfur source into the reaction cavity at a first temperature, and making the molybdenum source and the sulfur source alternately chemisorb on the surface of the substrate through an adsorption reaction epitaxy process to obtain alternately-stacked molybdenum source molecular layers and sulfur source molecular layers; S300, reacting the molybdenum source molecular layers and the sulfur source molecular layers at a second temperature to form a molybdenum disulfide precursor film; and S400, crystallizing the molybdenum disulfide precursor film at a third temperature to form a molybdenum disulfide film, wherein the first temperature, the second temperature and the third temperature increase in sequence. The preparation method of the molybdenum disulfide film provided by the application is used for realizing the preparation of a high-quality and low-pollution molybdenum disulfide film.

Description

Technical Field

[0001] This invention relates to the field of thin film growth technology, and in particular to a method for preparing molybdenum disulfide thin films. Background Technology

[0002] Two-dimensional materials, with their atomic-level thickness and tunable bandgap characteristics, are considered potential materials for breaking through the physical limits of silicon-based electronics. Among them, molybdenum disulfide (MoS2) has attracted much attention due to its wide bandgap (1.84 eV) in monolayer or few-layer forms, which can effectively suppress short-channel effects. However, the practical application of molybdenum disulfide (MoS2) is limited by existing preparation techniques. The number of film layers grown by chemical vapor deposition (CVD) is difficult to control precisely. Although atomic layer deposition (ALD) technology can achieve uniform deposition with controllable layer number, the subsequent high-temperature annealing and crystallization process usually requires transferring the film to other equipment, which can easily introduce contaminants and affect the film's performance. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing molybdenum disulfide thin films, which can be used to prepare high-quality, low-pollution molybdenum disulfide thin films.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a molybdenum disulfide thin film, comprising: S100, a substrate is provided and the substrate is placed in the reaction chamber; S200, at a first temperature, a molybdenum source and a sulfur source are alternately introduced into the reaction chamber, and the molybdenum source and the sulfur source are alternately chemically adsorbed onto the substrate surface through an adsorption reaction epitaxial process, resulting in alternating layers of molybdenum source molecular layers and sulfur source molecular layers. S300, at the second temperature, the molybdenum source molecular layer and the sulfur source molecular layer react to form a molybdenum disulfide precursor film; S400, at the third temperature, the molybdenum disulfide precursor film crystallizes to form a molybdenum disulfide film, wherein the first temperature, the second temperature, and the third temperature increase sequentially.

[0005] Optionally, in step S200, after each of the molybdenum source and the sulfur source precursors is chemically adsorbed onto the substrate surface, an inert gas is purged into the reaction chamber to remove any excess precursor source from the reaction chamber.

[0006] Optionally, in the step of purging the inert gas into the reaction chamber to remove excess precursor source from the reaction chamber, the time for purging the inert gas to remove the molybdenum source is 22s-28s; and / or; The time for purging the inert gas to remove the sulfur source is 28s-32s.

[0007] Optionally, the number of alternating cycles in step S200 may be one or more.

[0008] Optionally, steps S200, S300, and S400 constitute a total loop, and the total loop may be repeated once or multiple times.

[0009] Optionally, after completing one total cycle and before performing the next total cycle, an inert gas is purged into the reaction chamber to cool it down to the first temperature.

[0010] Optionally, in step S200, the molybdenum source introduction time is 0.2s-0.4s, the molybdenum source introduction flow rate is 8SCCM-12SCCM, and the molybdenum source adsorption time is 8s-12s; and / or; The sulfur source is introduced for 0.01s-0.03s, the sulfur source flow rate is 8SCCM-12SCCM, and the sulfur source adsorption time is 8s-12s.

[0011] Optionally, the first temperature is 80℃-120℃; and / or; The second temperature is 180℃-220℃; and / or; The third temperature is 850℃-950℃.

[0012] Optionally, in step S300, the reaction time is 2 min-3 min; and / or; In step S400, the crystallization time is 8s-12s.

[0013] Optionally, the molybdenum source is an organic molybdenum source and / or an inorganic molybdenum source; and / or; The sulfur source is an organic sulfur source and / or an inorganic sulfur source.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The method for preparing molybdenum disulfide thin films provided by this invention involves matching specific temperatures at different stages within the same reaction chamber. Through an adsorption-reaction epitaxy process, the adsorption, reaction, and crystallization steps are seamlessly integrated, and each step is carried out in its optimal thermal environment. This eliminates the problems of interface contamination and impurity adsorption introduced by transferring the film to another location for annealing in traditional processes, ensuring the cleanliness and integrity of the film. The first temperature ensures the stable adsorption of precursor molecules on the substrate surface; the second temperature drives the reaction of the adsorption layer; and the third temperature directly promotes in-situ crystallization of the film within the same reaction chamber, avoiding the risk of contamination from exposure to the atmosphere or transfer. By achieving precise and uniform control of the number of film layers through the adsorption-reaction epitaxy process, this invention prepares molybdenum disulfide thin films with clean interfaces, complete structures, and superior performance without relying on transfer annealing. Attached Figure Description

[0015] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart provided for an embodiment of the present invention; Figure 2 This is a flowchart illustrating step S200 provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the overall loop process provided in an embodiment of the present invention; Figure 4 A schematic diagram of nine sites used for characterization testing of the MoS2 thin film prepared in an embodiment of the present invention; Figure 5 Raman characterization results at nine sites of the MoS2 thin film prepared in the embodiments of the present invention; Figure 6 XPS characterization results of the MoS2 thin film prepared in the embodiments of the present invention. Detailed Implementation

[0016] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0017] 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0018] Please see Figure 1 The present invention provides a method for preparing a molybdenum disulfide thin film, comprising: Step S100: Provide a substrate and place the substrate inside the reaction chamber.

[0019] In this step, the vacuum level of the reaction chamber is: For example, the vacuum level of the reaction chamber can be... , , or The substrate can be a sapphire substrate.

[0020] In S200, at the first temperature, a molybdenum source and a sulfur source are alternately introduced into the reaction chamber. Through an adsorption reaction epitaxial process, the molybdenum source and the sulfur source are alternately chemically adsorbed onto the substrate surface to obtain alternating layers of molybdenum source molecules and sulfur source molecules.

[0021] In this step, the vacuum level of the reaction chamber is 0.12 Torr-0.18 Torr. For example, the vacuum level of the reaction chamber can be 0.12 Torr, 0.13 Torr, 0.15 Torr, 0.17 Torr, or 0.18 Torr. The specific sequence of alternately introducing the molybdenum source and the sulfur source into the reaction chamber is as follows: first, the molybdenum source is introduced, and after it completes surface chemisorption, the sulfur source is introduced. Alternating the introduction of the molybdenum source and the sulfur source into the reaction chamber ensures that only a monolayer is formed in each cycle, thereby achieving precise control of the film thickness; at the same time, the alternating chemisorption of the molybdenum source and the sulfur source on the substrate surface provides an ideal precursor structure for the subsequent formation of a molybdenum disulfide film with a stoichiometric ratio of 1:2, laying a key foundation for obtaining high-quality, uniform crystalline films.

[0022] In S300, at the second temperature, the molybdenum source molecular layer and the sulfur source molecular layer react to form a molybdenum disulfide precursor film.

[0023] This step involves raising the temperature from a first temperature to a second temperature, driving a full reaction between the molybdenum source monolayer and the sulfur source monolayer that have been alternately adsorbed on the substrate surface, thereby achieving a transition from chemisorption to chemibonding and generating a disordered stacked molybdenum disulfide transition layer with a stoichiometric ratio of 1:2.

[0024] In S400, at the third temperature, the molybdenum disulfide precursor film crystallizes to form a molybdenum disulfide film, wherein the first temperature, the second temperature, and the third temperature increase sequentially.

[0025] For example, during the temperature rise from the second temperature to the third temperature in the reaction chamber, the heating rate is 10℃ / s-15℃ / s. For example, the heating rate can be 10℃ / s, 12℃ / s, 13℃ / s, 14℃ / s, or 15℃ / s. A heating rate of 10℃ / s-15℃ / s minimizes the residence time of the precursor film in the intermediate temperature range, suppresses unfavorable reactions and component loss, and ensures that the precursor film quickly enters the high-temperature range suitable for high-quality crystallization. Based on the formation of the molybdenum disulfide precursor film in step S300, the third temperature in S400 provides sufficient energy to achieve long-range ordered epitaxial growth of the film, ultimately obtaining a high-quality molybdenum disulfide film. The sequential increase in the first, second, and third temperatures creates optimal process conditions for the three steps with different thermodynamic requirements: adsorption, reaction, and crystallization.

[0026] The method for preparing molybdenum disulfide thin films provided by this invention achieves the preparation of high-quality molybdenum disulfide thin films within the same reaction chamber through a three-step stepped heating process of adsorption-reaction-crystallization. First, the use of a single reaction chamber eliminates interfacial contamination and damage caused by annealing elsewhere, ensuring the cleanliness and integrity of the film. Second, the first, second, and third temperatures provide optimal thermodynamic conditions for the adsorption, reaction, and crystallization of the precursor, respectively. The synergistic effect of these two factors provides a stable foundation for preparing molybdenum disulfide thin films with clean interfaces, high crystallinity, and excellent performance. Figure 4 Prepared for embodiments of the present invention A schematic diagram of nine points used for characterization testing of the thin film, with ellipsometric and Raman characterization performed at each of the nine points. Figure 5 Prepared for embodiments of the present invention Raman characterization results at nine sites on the thin film showed that the characteristic peak positions and intensities remained consistent across different sites, with only slight fluctuations in the baseline. This indicates that the crystal structure, number of layers, and distribution of the thin film within the test area exhibit good spatial uniformity, with no local structural anomalies. Furthermore, the high intensity and sharp peak shape of the characteristic peaks indicate good crystallinity of molybdenum disulfide. In addition, the thin film prepared in the embodiments of this invention... The thin film was characterized by XPS. Figure 6 Prepared for embodiments of the present invention XPS characterization results of the thin film. XPS characterization results show obvious characteristic peaks of Mo and S orbitals in the spectrum, directly proving that the main constituent elements of the thin film are Mo and S, consistent with the chemical composition of molybdenum disulfide. Furthermore, the thin film prepared in the embodiments of this invention... The thin film was characterized by ellipsometry, and the characterization results are detailed in Table 1. Calculations based on the data in Table 1 show that the thin film prepared in the embodiments of this invention... The average thickness of the film at nine sites was 53.22 nm, with a range of 2.35 nm, indicating that the thickness fluctuation at the nine different sites was very small, demonstrating that the molybdenum disulfide film prepared by adsorption reaction epitaxy has excellent thickness uniformity.

[0027] Table 1. Preparations made in the examples Ellipsometry characterization results at nine points on the thin film Please see Figure 2 In some embodiments, in step S200, after each precursor source (molybdenum source or sulfur source) is chemically adsorbed onto the substrate surface, an inert gas is purged into the reaction chamber to remove excess precursor source. This purging step removes excess precursor source that did not participate in adsorption, ensuring that only a single chemically adsorbed monolayer remains on the substrate surface before the next precursor source is introduced. This guarantees that the film grows layer by layer, effectively ensuring the uniformity of the film composition and laying the technological foundation for obtaining a high-quality, stoichiometric molybdenum disulfide film.

[0028] Please see Figure 2 In some embodiments, during the step of purging the reaction chamber with inert gas to remove excess precursor sources, the time for purging the molybdenum source with inert gas is 22-28 seconds. For example, the purging time can be 22, 24, 25, 27, or 28 seconds. If the purging time is less than 22 seconds, incomplete removal of the molybdenum source may occur, disrupting the stoichiometry and uniformity of the film. If the purging time is greater than 28 seconds, excessive purging may lead to partial desorption of the adsorbed molybdenum source molecules, and also wastes unnecessary process time. Therefore, considering all factors, a purging time of 22-28 seconds is chosen. This time range ensures process efficiency while achieving the removal of residual molybdenum source, creating a clean reaction interface for subsequent sulfur source adsorption.

[0029] Please see Figure 2In some embodiments, during the step of purging the reaction chamber with inert gas to remove excess precursor sources, the time for purging the sulfur source with inert gas is 28-32 seconds. For example, the purging time can be 28, 29, 30, 31, or 32 seconds. If the purging time is less than 28 seconds, incomplete removal of the sulfur source may occur, leading to a high sulfur content in the film. If the purging time is greater than 32 seconds, excessive purging may cause partial desorption of the sulfur source chemically adsorbed on the substrate surface under the continuous action of a strong gas flow, disrupting the uniform growth of the film. Therefore, considering all factors, a purging time of 28-32 seconds is chosen to ensure that excess sulfur source is removed while avoiding over-purging.

[0030] Please see Figure 1 , Figure 2 and Figure 3 In some embodiments, the alternating cycle in step S200 is one or more times. Alternating the introduction of a molybdenum source and a sulfur source once constitutes one alternating cycle. For example, the alternating cycle in step S200 can be one, two, three, four, or more times. Performing one cycle can prepare a single-layer molybdenum disulfide film. Performing multiple cycles can obtain a multilayer molybdenum disulfide film, thereby adapting to the diverse material thickness requirements of different application scenarios.

[0031] Please see Figure 1 In some embodiments, steps S200, S300, and S400 constitute a total cycle, which may be repeated once or multiple times. For example, the total number of cycles may be one, two, three, four, or more. Performing one total cycle completes one adsorption-reaction-crystallization process, yielding a high-quality, fully crystalline molybdenum disulfide film suitable for ultrathin monolayer material applications. Repeating multiple total cycles allows for the stacking of multilayer films. Each film layer completes adsorption, reaction, and crystallization independently and at optimized temperatures, with clear boundaries between layers and each layer possessing complete crystalline quality, thus obtaining a multilayer molybdenum disulfide film with controllable thickness and clear interlayer interfaces.

[0032] Please see Figure 3 In some embodiments, after completing one total cycle and before starting the next total cycle, an inert gas is purged into the reaction chamber to cool it to a first temperature, i.e., step [step name missing]. For example, the time for purging the reaction chamber with inert gas is 1300s-1350s, specifically 1300s, 1320s, 1325s, 1340s, or 1350s. After completing one cycle, purging the reaction chamber with inert gas can quickly and uniformly lower the temperature of the substrate and the reaction chamber to a first temperature, creating a stable initial temperature environment for starting the next cycle, so that the cycle reaction can proceed normally.

[0033] Please see Figure 1 and Figure 3 In some embodiments, in step S200, the molybdenum source introduction time is 0.2s-0.4s, the molybdenum source flow rate is 8SCCM-12SCCM, and the molybdenum source adsorption time is 8s-12s. For example, the molybdenum source introduction time can be 0.2s, 0.25s, 0.3s, 0.35s, or 0.4s, etc.; the molybdenum source flow rate can be 8SCCM, 9SCCM, 10SCCM, 11SCCM, or 12SCCM, etc.; and the molybdenum source adsorption time can be 8s, 9s, 10s, 11s, or 12s. If the molybdenum source introduction time is less than 0.2s, insufficient molybdenum source precursor may enter the reaction chamber, preventing saturated chemisorption on the substrate surface and resulting in an incomplete adsorption layer. If the molybdenum source introduction time is greater than 0.4s, unnecessary waste of the precursor will increase raw material costs, and excess molybdenum source precursor may remain in the reaction chamber due to failure to be purged in time. Therefore, considering all factors, the molybdenum source introduction time should be selected between 0.2s and 0.4s. If the molybdenum source flow rate is less than 8 SCCM, the transport rate of the precursor source to the substrate surface may be insufficient, making it difficult to achieve the target surface concentration within the set time, potentially leading to incomplete adsorption. If the molybdenum source flow rate is greater than 12 SCCM, the excessive flow rate may interfere with the already formed adsorption layer. Therefore, considering all factors, the molybdenum source flow rate should be selected between 8 SCCM and 12 SCCM. If the molybdenum source adsorption time is less than 8s, the surface adsorption may not reach saturation, resulting in defects in the adsorption layer. If the molybdenum source adsorption time is greater than 12s, after chemical adsorption has been completed, the excessively long adsorption time will not increase the adsorption amount but will instead prolong the process time of a single cycle, reducing production efficiency. Therefore, considering all factors, the molybdenum source adsorption time should be selected between 8s and 12s.

[0034] Please see Figure 1 and Figure 3In some embodiments, in step S200, the sulfur source introduction time is 0.01s-0.03s, the sulfur source flow rate is 8SCCM-12SCCM, and the sulfur source adsorption time is 8s-12s. For example, the sulfur source introduction time can be 0.01s, 0.015s, 0.02s, 0.025s, or 0.03s, etc.; the sulfur source flow rate can be 8SCCM, 9SCCM, 10SCCM, 11SCCM, or 12SCCM; and the sulfur source adsorption time can be 8s, 9s, 10s, 11s, or 12s, etc. If the sulfur source introduction time is less than 0.01s, insufficient sulfur source precursor may enter the reaction chamber, failing to fully react with the adsorbed molybdenum source layer; if the sulfur source introduction time is greater than 0.03s, an excess of sulfur source will occur, making it difficult to remove the excess sulfur source during subsequent purging. Therefore, considering all factors, a sulfur source introduction time of 0.01s-0.03s is selected. If the sulfur source flow rate is less than 8 SCCM, the transport rate of the sulfur source precursor to the reaction chamber will be insufficient, making it difficult to achieve the target surface concentration within the set time, potentially leading to incomplete adsorption. If the sulfur source flow rate is greater than 12 SCCM, the excessive flow rate may damage the already formed adsorption layer. Therefore, considering all factors, the sulfur source flow rate should be selected between 8 SCCM and 12 SCCM. If the sulfur source adsorption time is less than 8 seconds, the sulfur source cannot diffuse sufficiently, affecting the uniformity of the film. If the sulfur source adsorption time is greater than 12 seconds, after the reaction has reached saturation, the excess adsorption time will prolong the cycle and reduce production efficiency. Therefore, considering all factors, the sulfur source adsorption time should be selected between 8 seconds and 12 seconds.

[0035] Please see Figure 1 and Figure 3 In some embodiments, the first temperature is 80℃-120℃. For example, the first temperature can be 80℃, 90℃, 100℃, 110℃, or 120℃. If the first temperature is less than 80℃, the substrate temperature is too low, and the migration rate of the precursor molecules on the substrate surface is insufficient, making it difficult to fully diffuse to all active sites, potentially leading to uneven adsorption and unsaturation. If the first temperature is greater than 120℃, the excessively high temperature will significantly increase the migration rate of the precursor on the substrate surface, potentially triggering unfavorable side reactions. Therefore, considering all factors, the first temperature is chosen to be 80℃-120℃.

[0036] Please see Figure 1 and Figure 3In some embodiments, the second temperature is 180℃-220℃. For example, the second temperature can be 180℃, 190℃, 200℃, 210℃, or 220℃. If the second temperature is less than 180℃, it is difficult to drive the adsorbed molybdenum and sulfur sources to undergo a sufficient chemical reaction. Incomplete reactions will result in a large number of unreacted molybdenum and sulfur source precursors or intermediate states in the film, ultimately leading to poor film crystallinity. If the second temperature is greater than 220℃, the high temperature may cause excessive desorption of the sulfur source or decomposition of the precursor, causing the film to deviate from the preset stoichiometric ratio and disrupting the uniformity and continuity of the film. Therefore, considering all factors, the second temperature is selected as 180℃-220℃.

[0037] Please see Figure 1 and Figure 3 In some embodiments, the third temperature is 850℃-950℃. For example, the third temperature can be 850℃, 870℃, 900℃, 920℃, or 950℃. If the third temperature is below 850℃, the crystallization process may be incomplete, making it difficult to obtain a high-quality thin film; if the third temperature is above 950℃, maintaining the excessively high temperature requires higher energy consumption, placing higher demands on the thermal stability of the substrate and reaction chamber, and reducing the economics of the process. Therefore, considering all factors, the third temperature is selected as 850℃-950℃.

[0038] Please see Figure 1 and Figure 3 In some embodiments, the reaction time in step S300 is 2-3 minutes. For example, the reaction time can be 2 minutes, 2.2 minutes, 2.5 minutes, 2.8 minutes, or 3 minutes. If the reaction time is less than 2 minutes, the reaction process may be incomplete, and unreacted precursor molecules or unstable intermediate phases may remain in the precursor film, affecting the final film quality. If the reaction time is greater than 3 minutes, continuing to extend the reaction time after reaching thermodynamic equilibrium will prolong the overall process cycle and reduce production efficiency. Therefore, considering all factors, a reaction time of 2-3 minutes is chosen.

[0039] Please see Figure 1 and Figure 3 In some embodiments, the crystallization time in step S400 is 8s-12s. For example, the crystallization time can be 8s, 9s, 10s, 11s, or 12s. If the crystallization time is less than 8s, the crystallization process may be incomplete, leaving a large number of amorphous regions in the film, severely degrading the film's performance. If the crystallization time is greater than 12s, extending the high-temperature processing time after the crystallization process is complete will directly lead to increased energy consumption and exacerbate substrate loss, reducing the economics of the process. Therefore, considering all factors, a crystallization time of 8s-12s is chosen.

[0040] Please see Figure 1 , Figure 2 and Figure 3 In some embodiments, the molybdenum source is an organic molybdenum source and / or an inorganic molybdenum source. For example, the molybdenum source can be molybdenum hexacarbonyl, molybdenum pentachloride, bis(cyclopentadienyl)dicarbonylmolybdenum, etc., with molybdenum hexacarbonyl being preferred. After the reaction of molybdenum hexacarbonyl with the sulfur source, the main reaction byproducts are carbon dioxide and water. These byproducts are clean and environmentally friendly, and are easily and completely removed by purging with an inert gas, preventing the introduction of other metals into the film, which is beneficial for obtaining high-purity molybdenum disulfide films.

[0041] Please see Figure 1 , Figure 2 and Figure 3 In some embodiments, the sulfur source is an organic sulfur source and / or an inorganic sulfur source. For example, the sulfur source can be diethyl disulfide, tert-butanethiol, di-tert-butyl disulfide, hydrogen sulfide, etc., with diethyl disulfide being preferred. Compared to highly toxic and corrosive sulfur sources, diethyl disulfide is safer to use and handle, significantly reducing process hazards and equipment corrosion requirements. Furthermore, the reaction byproducts are clean and easily discharged, contributing to the acquisition of high-purity, high-quality molybdenum disulfide films.

[0042] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0043] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a molybdenum disulfide thin film, characterized in that, include: S100, a substrate is provided and the substrate is placed in the reaction chamber; S200, at a first temperature, a molybdenum source and a sulfur source are alternately introduced into the reaction chamber, and the molybdenum source and the sulfur source are alternately chemically adsorbed onto the substrate surface through an adsorption reaction epitaxial process, resulting in alternating layers of molybdenum source molecular layers and sulfur source molecular layers. S300, at the second temperature, the molybdenum source molecular layer and the sulfur source molecular layer react to form a molybdenum disulfide precursor film; S400, at the third temperature, the molybdenum disulfide precursor film crystallizes to form a molybdenum disulfide film, wherein the first temperature, the second temperature, and the third temperature increase sequentially.

2. The method for preparing a molybdenum disulfide thin film according to claim 1, characterized in that, In step S200, after each of the precursor sources, the molybdenum source and the sulfur source, is chemically adsorbed onto the substrate surface, an inert gas is blown into the reaction chamber to remove any excess precursor source from the reaction chamber.

3. The method for preparing molybdenum disulfide thin film according to claim 2, characterized in that, In the step of purging the inert gas into the reaction chamber to remove excess precursor source from the reaction chamber, the time for purging the inert gas to remove the molybdenum source is 22s-28s; and / or The time for purging the inert gas to remove the sulfur source is 28s-32s.

4. The method for preparing a molybdenum disulfide thin film according to claim 1, characterized in that, The alternation cycle in step S200 can be one or more times.

5. The method for preparing a molybdenum disulfide thin film according to claim 1, characterized in that, Steps S200, S300, and S400 constitute a total loop, and the total loop may be repeated once or multiple times.

6. The method for preparing a molybdenum disulfide thin film according to claim 5, characterized in that, After completing one total cycle and before starting the next total cycle, inert gas is purged into the reaction chamber to cool it down to the first temperature.

7. The method for preparing a molybdenum disulfide thin film according to claim 1, characterized in that, In step S200, the molybdenum source introduction time is 0.2s-0.4s, the molybdenum source flow rate is 8SCCM-12SCCM, and the molybdenum source adsorption time is 8s-12s; and / or The sulfur source is introduced for 0.01s-0.03s, the sulfur source flow rate is 8SCCM-12SCCM, and the sulfur source adsorption time is 8s-12s.

8. The method for preparing a molybdenum disulfide thin film according to claim 1, characterized in that, The first temperature is 80℃-120℃; and / or The second temperature is 180℃-220℃; and / or The third temperature is 850℃-950℃.

9. The method for preparing a molybdenum disulfide thin film according to claim 1, characterized in that, In step S300, the reaction time is 2 min-3 min; and / or In step S400, the crystallization time is 8s-12s.

10. The method for preparing a molybdenum disulfide thin film according to claim 1, characterized in that, The molybdenum source is an organic molybdenum source and / or an inorganic molybdenum source; and / or The sulfur source is an organic sulfur source and / or an inorganic sulfur source.

Images