Method for preparing centimeter-level molybdenum disulfide film at low pressure
By utilizing Na ions to catalyze the lateral growth of MoS2 thin films under low pressure, the problem of directly growing high-quality MoS2 thin films on SiO2/Si substrates has been solved, achieving large-area and uniform thin film preparation suitable for electrical devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-06
- Publication Date
- 2026-04-14
AI Technical Summary
Existing technologies make it difficult to directly grow high-quality MoS2 films on silicon dioxide/silicon substrates, and the introduction of Na ions to assist growth can lead to residual impurities or transfer processes that affect film performance.
A low-pressure preparation method was used to generate a MoS2 thin film on a soda-lime glass substrate and deposit it onto a SiO2/Si substrate by means of a carrier gas. The lateral growth of MoS2 was catalyzed by Na ions, and the evaporation and reaction of MoCl5 were controlled under low-pressure vacuum conditions to achieve the direct growth of the MoS2 thin film.
High-quality centimeter-scale MoS2 thin films with large area and uniformity were prepared on SiO2/Si substrates, making them suitable for applications in electrical devices.
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Figure CN121865856A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of semiconductor material preparation technology, and particularly relates to a method for preparing centimeter-scale molybdenum disulfide thin films under low pressure. Background Technology
[0002] Two-dimensional transition metal chalcogenides (TMDCs) are a class of layered materials connected in-plane by covalent bonds and interacting between layers by van der Waals forces. Molybdenum disulfide (MoS2), as one of the earliest studied TMDCs, is considered a promising candidate for next-generation semiconductor materials due to its unique electrical properties. Therefore, the study of MoS2 thin film preparation is of great significance for both basic research and practical applications.
[0003] Studies show that the presence of sodium (Na) ions effectively lowers the formation barrier of MoS2, promoting the lateral growth of its domains and thus obtaining MoS2 films with larger domains and fewer defects. Currently, there are two main ways to introduce Na ions to assist MoS2 growth: one is to add sodium chloride powder to the molybdenum source, but the prepared MoS2 film often has unreacted excess Na2S particles remaining on the surface, which affects the uniformity of the film's performance and its subsequent applications; the other is to directly grow MoS2 films on soda-lime glass, but the MoS2 film needs to be transferred to a silicon dioxide / silicon (SiO2 / Si) working substrate for further application. This transfer process obviously affects the film's performance. Therefore, how to introduce Na ions to assist in the direct growth of MoS2 films on silicon dioxide / silicon substrates remains a problem worth exploring. Summary of the Invention
[0004] The purpose of this invention is to provide a method for low-pressure preparation of centimeter-scale MoS2 thin films, which effectively introduces Na ions to assist in the growth process on silicon dioxide / silicon substrates, thereby obtaining high-quality MoS2 thin films and further promoting their application in electrical devices.
[0005] The technical solution adopted in this invention is as follows:
[0006] A method for preparing centimeter-scale MoS2 thin films by low pressure includes the following steps:
[0007] (1) Cleaning the graphite boat and substrate: Place the graphite boat, centimeter-sized soda-lime glass and heavily p-doped SiO2 / Si substrate into acetone and sonicate for 15 min, then into anhydrous ethanol for 15 min, then into deionized water for 15 min, and finally dry them with a nitrogen gun.
[0008] (2) Weigh sulfur powder (S) using an electronic scale and place it in a graphite boat; weigh molybdenum pentachloride powder (MoCl5) using an electronic scale, spread the weighed MoCl5 powder evenly in another graphite boat, and then cover it with soda-lime glass; sequentially place the two graphite boats and the SiO2 / Si substrate into a quartz tube, positioned outside the heating zone of the tube furnace, such as... Figure 1 As shown.
[0009] (3) Preparation of MoS2 thin films: a) Hold the argon gas at 500 sccm for 10 min to remove residual gas in the quartz tube; b) Adjust the argon gas and pressure to the growth flow rate and growth pressure, respectively, then raise the first, second, and third temperature zones to the growth temperature, and finally use a slide rail to move the tube furnace to the S powder, MoCl5, and SiO2 / Si substrate (e.g., ...). Figure 2 (as shown); c) Hold the temperature for growth time to grow the MoS2 film, and then let it cool naturally to room temperature to obtain a centimeter-scale MoS2 film.
[0010] Furthermore, in step (2), the mass of S powder is 30-2000 mg.
[0011] Furthermore, in step (2), the mass of MoCl5 powder is 1-50 mg.
[0012] Furthermore, in step (3), the argon growth flow rate is 10-200 sccm.
[0013] Furthermore, in step (3), the growth pressure is 50-1000 Pa.
[0014] Furthermore, in step (3), the temperature of the first temperature zone is 150-350℃.
[0015] Furthermore, in step (3), the temperature of the second temperature zone is 750-850℃.
[0016] Furthermore, in step (3), the temperature of the third temperature zone is 750-900℃.
[0017] Furthermore, in step (3), the growth time is 5-60 min.
[0018] In summary, by adopting the above technical solution, the beneficial effects of the present invention are:
[0019] (1) In this invention, in step (3), under the catalytic action of Na ions, S and MoCl5 react inside the molten soda-lime glass to generate MoS2; then, MoS2 diffuses to the surface of the molten glass; finally, driven by the carrier gas, a continuous thin film is deposited on the downstream SiO2 / Si substrate. The presence of Na ions will effectively reduce the formation barrier of MoS2, thereby promoting the lateral growth of crystal domains and suppressing the formation of defects, thus forming a high-quality thin film.
[0020] (2) In this invention, since the melting point of MoCl5 is lower than that of soda-lime glass, it is easy to evaporate before the soda-lime glass melts under low pressure vacuum conditions and be carried away by the carrier gas to be deposited on the SiO2 / Si substrate. Therefore, the method of shortening the heating time of MoCl5 is adopted (first heating to the growth temperature and then moving to the sample, step (3)), so that MoCl5 can be more easily integrated into the molten soda-lime glass as a Mo source, which is beneficial to the fact that the reaction of MoS2 in step (3) occurs in the molten soda-lime glass so that Na ions can play a catalytic role.
[0021] (3) In this invention, since the melting point of MoCl5 is lower than that of soda-lime glass, it is easy to evaporate and be carried away by the carrier gas and deposited on the SiO2 / Si substrate before the soda-lime glass melts under low pressure vacuum conditions. Therefore, the method of covering MoCl5 powder with soda-lime glass is adopted (step (2)), which makes it easier for MoCl5 to be incorporated into the molten soda-lime glass as a Mo source. This is beneficial to the fact that the reaction of MoS2 in step (3) occurs in the molten soda-lime glass so that Na ions can play a catalytic role.
[0022] (4) The low-pressure vacuum vapor deposition method (pressure 50-1000Pa) used in this invention is beneficial to the migration and growth of MoS2 molecules on SiO2 / Si substrate, so that the prepared MoS2 film has the advantages of large area and uniformity.
[0023] (5) In this invention, the number of layers of the MoS2 film can be controlled by the quality of MoCl5 in step (2) and the growth time in step (3).
[0024] (6) In this invention, high-quality centimeter-scale MoS2 thin films are directly synthesized on SiO2 / Si substrates, which is beneficial for their application in electrical devices. Attached Figure Description
[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 This is a schematic diagram of the apparatus for preparing MoS2 thin films according to the present invention.
[0027] Figure 2 This is a schematic diagram of the apparatus for preparing MoS2 thin films according to the present invention.
[0028] Figure 3 This is an optical photograph of the centimeter-scale bilayer MoS2 thin film prepared in Example 1.
[0029] Figure 4 This is an optical microscope image of the centimeter-scale bilayer MoS2 thin film prepared in Example 1;
[0030] Figure 5 This is the Raman spectrum of the bilayer MoS2 thin film prepared in Example 1. Detailed Implementation
[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the 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 only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0032] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.
[0033] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0034] The features and performance of the present invention will be further described in detail below with reference to embodiments.
[0035] Example 1
[0036] (1) Cleaning the graphite boat and substrate: Clean the graphite boat and substrate respectively (1×1cm). 2 Sodium-calcium glass and heavily p-doped SiO2 / Si substrates were placed in acetone and sonicated for 15 min, then in anhydrous ethanol for 15 min, then in deionized water for 15 min, and finally dried with a nitrogen gun.
[0037] (2) Weigh 200 mg of S powder using an electronic scale and place it in a graphite boat; weigh 5 mg of MoCl5 powder using an electronic scale, spread the weighed MoCl5 powder evenly in another graphite boat, and then cover it with soda-lime glass; sequentially place the two graphite boats and the SiO2 / Si substrate into a quartz tube, positioned outside the heating zone of the tube furnace, such as... Figure 1 As shown.
[0038] (3) Preparation of MoS2 thin film: a) Hold at argon gas at 500 sccm for 10 min to remove residual gas in the quartz tube; b) Adjust the argon gas and pressure to 100 sccm and 200 Pa respectively, then raise the first, second and third temperature zones to 200℃, 800℃ and 850℃ respectively, and finally use a slide rail to move the tube furnace to the S powder, MoCl5 and SiO2 / Si substrate (e.g. Figure 2 (as shown); c) Keep warm for 10 min to grow MoS2 film, then cool naturally to room temperature to obtain centimeter-scale bilayer MoS2 film.
[0039] Optical photographs and optical microscope images of the centimeter-scale MoS2 thin films grown in Example 1 are shown below. Figure 3 and Figure 4 As shown, the film exhibits centimeter-scale dimensions and optical uniformity. Figure 5 The Raman spectra of the prepared centimeter-scale MoS2 films showed that they had a bilayer structure, typical of A 1g and E 2g 1 The difference between the peaks is approximately 21.6 cm. -1 .
[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing centimeter-scale molybdenum disulfide (MoS2) thin films under low pressure, comprising the following steps: (1) Cleaning the graphite boat and substrate: Place the graphite boat, centimeter-sized soda-lime glass and heavily p-doped SiO2 / Si substrate into acetone and sonicate for 15 min, then into anhydrous ethanol for 15 min, then into deionized water for 15 min, and finally dry them with a nitrogen gun. (2) Weigh 30-2000 mg of sulfur powder (S) using an electronic scale and place it in a graphite boat; weigh 1-50 mg of molybdenum pentachloride powder (MoCl5) using an electronic scale, spread the weighed MoCl5 powder evenly in another graphite boat, and then cover it with soda-lime glass; send the two graphite boats and the SiO2 / Si substrate into the quartz tube in sequence, which is located outside the heating zone of the tube furnace, as shown in Figure 1. (3) Preparation of MoS2 thin film: a) Hold at 500 sccm of argon for 10 min to remove residual gas in the quartz tube; b) Adjust the argon flow rate and pressure to 10-200 sccm and the growth pressure to 50-1000 Pa, respectively. Then, raise the first, second and third temperature zones to the growth temperatures of 150-350℃, 750-850℃ and 750-900℃, respectively. Finally, use a slide rail to move the tube furnace to the S powder, MoCl5 and SiO2 / Si substrate (as shown in Figure 2); c) Hold at the temperature for 5-60 min to grow MoS2 thin film, and then cool naturally to room temperature to obtain centimeter-scale MoS2 thin film.
2. The method for preparing centimeter-scale MoS2 thin films under low pressure according to claim 1, characterized in that: In step (3), under the catalysis of Na ions, S and MoCl5 react inside the molten soda-lime glass to generate MoS2; then, MoS2 diffuses to the surface of the molten glass; finally, driven by the carrier gas, a continuous thin film is deposited on the downstream SiO2 / Si substrate. The presence of Na ions effectively reduces the formation barrier of MoS2, thereby promoting the lateral growth of crystal domains and suppressing the formation of defects, thus forming a high-quality thin film.
3. The method for preparing centimeter-scale MoS2 thin films under low pressure according to claim 1, characterized in that: Since the melting point of MoCl5 is lower than that of soda-lime glass, it is easy to evaporate before the soda-lime glass melts under low-pressure vacuum conditions and be carried away by the carrier gas to deposit on the SiO2 / Si substrate. Therefore, the method of shortening the heating time of MoCl5 is adopted (first heating to the growth temperature and then moving to the sample, step (3)), which makes it easier for MoCl5 to be incorporated into the molten soda-lime glass as a Mo source. This is beneficial because the reaction of MoS2 in step (3) occurs in the molten soda-lime glass, so that Na ions can play a catalytic role.
4. The method for low-pressure two-step preparation of centimeter-scale MoS2 thin films according to claim 1, characterized in that: Since the melting point of MoCl5 is lower than that of soda-lime glass, it is easy to evaporate before the soda-lime glass melts under low-pressure vacuum conditions and be carried away by the carrier gas to deposit on the SiO2 / Si substrate. Therefore, the method of covering the MoCl5 powder with soda-lime glass is adopted (step (2)). This makes it easier for MoCl5 to be incorporated into the molten soda-lime glass as a Mo source, which is beneficial to the fact that the reaction of MoS2 in step (3) occurs in the molten soda-lime glass so that Na ions can play a catalytic role.
5. The method for preparing centimeter-scale MoS2 thin films under low pressure according to claim 1, characterized in that: The low-pressure vacuum vapor deposition method (pressure 50-1000Pa) is beneficial to the migration and growth of MoS2 molecules on SiO2 / Si substrate, resulting in MoS2 films with advantages of large area and uniformity.
6. The method for preparing centimeter-scale MoS2 thin films under low pressure according to claim 1, characterized in that: The number of layers in the MoS2 film can be controlled by the mass of MoCl5 in step (2) and the growth pressure and growth time in step (3).