Preparation method of two-dimensional transition metal disulfide film

Abstract

The invention discloses a preparation method of a two-dimensional transition metal disulfide film, and the preparation method comprises the following steps: providing a substrate, carrying out the surface treatment of the substrate, and forming a step which exposes uniform orientation on the surface of the substrate; dissolving a transition metal source and a doped metal source in a solvent to obtain a precursor solution; spin-coating a substrate with the precursor solution, and forming a precursor film on the substrate; and putting a non-metal source and the substrate with the precursor film prepared on the surface into a tubular furnace, heating the tubular furnace, and forming the metal-doped two-dimensional transition metal disulfide film on the surface of the substrate. According to the invention, the doped metal source and the transition metal source are mixed to prepare the precursor solution, and the precursor solution is spin-coated on the substrate with the step to grow the film, so that the stable supply of the doped metal source in the metal doping process of the two-dimensional transition metal disulfide film is ensured; and stable and controllable doping of the two-dimensional transition metal disulfide film is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of nanomaterials and semiconductor materials, and particularly relates to a method for preparing a two-dimensional transition metal dichalcogenide film. Background Art

[0002] Two-dimensional transition metal dichalcogenides (TMDs) are widely used in optical and electrical fields due to their unique semiconductor properties. To expand the physical and chemical properties of TMDs, various metal elements have been introduced into single-layer TMD films as dopants. For example, the p-type dopant F4-TCN greatly improves the photoluminescence intensity of single-layer MoS2 films; compared with native single-layer WS2 films, Nb doping into single-layer WS2 films can obtain different transport properties; co-doped single-layer MoS2 films exhibit excellent electrocatalytic performance, with significantly reduced overpotential and Tafel slope; single-layer MoS2 films doped with Fe, Mn, and Co induce the emergence of ferromagnetism at room temperature, while native single-layer MoS2 films do not have this property. All of the above studies show that doping technology is expected to break through the current research bottleneck of two-dimensional materials and may give two-dimensional materials more flexible application potential.

[0003] However, the main doping method for TMD materials is currently chemical vapor deposition (CVD), but the doping process of this method is uncontrollable. At the same time, due to the self-purification effect of the material during the doping process, it will cause the precipitation of dopants and make it difficult to dope the required elements into the main material. This situation is particularly difficult to control in single-layer thin film materials. Therefore, there is an urgent need for a universal method that can achieve controllable doping of TMD materials to solve the above technical problems, and it is expected to realize the industrial controllable preparation of doped materials in the future.

[0004] Therefore, in order to solve the above technical problems, it is necessary to provide a method for preparing a two-dimensional transition metal dichalcogenide thin film. Summary of the Invention

[0005] The object of the present invention is to provide a method for preparing a two-dimensional transition metal dichalcogenide thin film, which can achieve controllable metal doping in a single-layer two-dimensional transition metal dichalcogenide thin film.

[0006] In order to achieve the above-mentioned purpose, the technical solution provided by one embodiment of the present invention is as follows:

[0007] A method for preparing a two-dimensional transition metal dichalcogenide thin film, the method comprising the following steps:

[0008] Providing a substrate and performing surface treatment on the substrate to form steps with uniform orientation exposed on the surface of the substrate;

[0009] dissolving a transition metal source and a doping metal source in a solvent to obtain a precursor solution;

[0010] spin-coating the precursor solution onto the substrate to form a precursor film on the substrate;

[0011] A non-metallic source and a substrate with a precursor film prepared on the surface are placed in a tube furnace, and the tube furnace is heated to form a metal-doped two-dimensional transition metal dichalcogenide film on the surface of the substrate.

[0012] In one embodiment, the area of ​​the metal-doped two-dimensional transition metal dichalcogenide film is 0.1 cm 2 ~1cm 2 .

[0013] In one embodiment, the step height of the substrate surface is 0.5 nm to 1 nm.

[0014] In one embodiment, the transition metal element is one or more of W and Mo, the doping metal element is one or more of Yb, Fe, Co, Ni, Mn, and Cr, and the chalcogenide element in the chalcogenide is one or more of S, Se, and Te.

[0015] In one embodiment, the two-dimensional transition metal dichalcogenide film is a single-layer WS2 film, the transition metal source is sodium tungstate powder, the doping metal source is one or more of YbCl3, FeCl3, CoCl2, NiCl2, MnCl2, CrCl2, and the non-metallic source is sulfur powder.

[0016] In one embodiment, in the step of spin-coating the precursor solution onto the substrate, the spin-coating speed of the precursor solution is 7000 r / min to 9000 r / min.

[0017] In one embodiment, the tubular furnace is a multi-temperature zone tubular furnace, which includes a first temperature zone located upstream and a second temperature zone located downstream, wherein the temperature of the second temperature zone is greater than the temperature of the first temperature zone, the non-metallic source is placed in the first temperature zone, and the substrate with a precursor film prepared on the surface is placed in the second temperature zone.

[0018] In one embodiment, heating the tube furnace specifically includes:

[0019] Raise the temperature of the first temperature zone to 150°C to 300°C, and raise the temperature of the second temperature zone to 780°C to 820°C;

[0020] After heating, keep warm for 5 to 15 minutes;

[0021] Allow the multi-temperature zone tube furnace to cool naturally to room temperature.

[0022] In one embodiment, the heating process of the tube furnace further includes: continuously mixing and introducing argon and hydrogen as transport and protective gases.

[0023] In one embodiment, before heating the tube furnace, the method further comprises:

[0024] The tubular furnace was evacuated and argon gas was repeatedly introduced for purge to exhaust the air in the tubular furnace.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention mixes a doping metal source and a transition metal source to form a precursor solution, and uses a stepped substrate for thin film growth. This solves the problem of difficulty in doping due to the self-purification effect of the material during the doping process, ensures a stable supply of the doping metal source during the metal doping process of the two-dimensional transition metal dichalcogenide film, and achieves stable and controllable doping of the two-dimensional transition metal dichalcogenide film.

[0027] The present invention utilizes the high surface energy effect of the step edge on the substrate surface to promote the spontaneous movement, adsorption and nucleation of crystal seeds, thereby realizing the controllable growth of crystal nuclei. In addition, the orientation of the steps on the substrate surface can induce the oriented growth of metal-doped two-dimensional transition metal dichalcogenide films, thereby realizing the growth of centimeter-scale single-layer metal-doped two-dimensional transition metal dichalcogenide films. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 Schematic diagram of the process for preparing a two-dimensional transition metal dichalcogenide thin film according to the present invention;

[0030] Figure 2 This is an atomic force microscope image of the substrate surface after high-temperature annealing in Example 1 of the present invention;

[0031] Figures 3a-3b 1 is a process flow chart of the method for preparing a two-dimensional transition metal dichalcogenide thin film in Example 1 of the present invention;

[0032] Figure 4 This is an atomic force microscope image of the crystal nuclei being self-driven and directional attached to the substrate in Example 1 of the present invention;

[0033] Figure 5This is an optical microscope image of an oriented Yb-doped WS2 thin film grown on a substrate in Example 1 of the present invention;

[0034] Figure 6 This is an atomic force microscope image of the oriented Yb-doped WS2 thin film grown on the substrate in Example 1 of the present invention;

[0035] Figure 7 This is an optical microscope image of the oriented splicing of the Yb-doped WS2 thin film grown on the substrate in Example 1 of the present invention;

[0036] Figure 8 This is an optical microscope image of a Yb-doped WS2 film with scratches in Example 1 of the present invention;

[0037] Figure 9 This is a macroscopic photograph of the Yb-doped WS2 thin film grown on a sapphire substrate in Example 1 of the present invention;

[0038] Figure 10 The Raman E is obtained by randomly selecting points on the large-area Yb-doped WS2 film in Example 1 of the present invention. 2g Statistical graphs of peak half-width and photoluminescence peak position;

[0039] Figure 11 This is the photoluminescence mapping diagram of the Yb-doped WS2 thin film at room temperature in Example 1 of the present invention;

[0040] Figure 12 1 is a comparison chart of the Raman peak positions of the thin films prepared in Example 1 of the present invention and Comparative Example 1;

[0041] Figures 13a-13b A comparison of X-ray photoelectron spectrum peak positions of the thin films prepared in Example 1 of the present invention and Comparative Example 1 in different binding energy ranges;

[0042] Figure 14 The scanning transmission electron microscope image and atomic distribution of the thin film prepared in Comparative Example 1 of the present invention and the scanning transmission electron microscope image and atomic distribution of the thin film prepared in Example 1 are respectively;

[0043] Figure 15 These are optical microscope images of the films prepared in Examples 1, 2, 3, 4, 5, and 6 of the present invention;

[0044] Figure 16 1 is a comparison chart of Raman peak positions of the films prepared in Comparative Example 1, Example 2, Example 3, Example 4, Example 5, and Example 6 of the present invention;

[0045] Figure 17This is a comparison chart of the photoluminescence peak positions of the thin films prepared in Comparative Example 1, Example 2, Example 3, Example 4, Example 5, and Example 6 of the present invention. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0047] Ginseng Figure 1 As shown, the present invention discloses a method for preparing a two-dimensional transition metal dichalcogenide thin film, comprising the following steps:

[0048] Providing a substrate and performing surface treatment on the substrate to form steps with uniform orientation exposed on the surface of the substrate;

[0049] dissolving a transition metal source and a doping metal source in a solvent to obtain a precursor solution;

[0050] spin-coating the precursor solution onto the substrate to form a precursor film on the substrate;

[0051] A non-metallic source and a substrate with a precursor film prepared on the surface are placed in a tube furnace, and the tube furnace is heated to form a metal-doped two-dimensional transition metal dichalcogenide film on the surface of the substrate.

[0052] The present invention is further described below with reference to specific examples.

[0053] Example 1:

[0054] In the metal-doped two-dimensional transition metal dichalcogenide thin film of this embodiment, the transition metal element is one or more of W and Mo, the doping metal element is one or more of Yb, Fe, Co, Ni, Mn, and Cr, and the chalcogenide element in the chalcogenide is one or more of S, Se, and Te. Two-dimensional transition metal dichalcogenide thin films include, but are not limited to, WS2 thin films, MoS2 thin films, and WSe2 thin films.

[0055] As a typical member of TMD materials, WS2 single-layer film has higher direct band gap luminescence efficiency and higher carrier mobility than MoS2 film (the mobility of single-layer WS2 film reaches 214cm2V at room temperature). -1 s -1) and has an atomically flat interface, which makes its integration with other materials not restricted by lattice matching. It has a high degree of freedom in heterogeneous integration of optoelectronic chips and has received increasing attention in recent years.

[0056] In this embodiment, metal doping in a single-layer WS2 thin film is used as an example for description. The specific preparation method includes the following steps:

[0057] S1. Provide a substrate and perform surface treatment on the substrate to form steps with uniform orientation exposed on the surface of the substrate.

[0058] The substrate is a sapphire substrate, a mica substrate or a single crystal silicon substrate, preferably a commercial sapphire substrate.

[0059] For example, in this embodiment, high temperature annealing is used to treat the surface of the substrate to reconstruct the surface lattice, thereby causing the substrate surface to expose steps with uniform orientation. The step height on the substrate surface is 0.5nm to 1nm. Figure 2 As shown, in this embodiment, the step height of the substrate surface is about 0.77 nm.

[0060] S2. Dissolving the transition metal source and the doping metal source in a solvent to obtain a precursor solution.

[0061] In this embodiment, the transition metal source is sodium tungstate powder, the solvent is ultrapure water, and the doping metal source includes, but is not limited to, one or more of YbCl3, FeCl3, CoCl2, NiCl2, MnCl2, and CrCl2. For example, the doping metal source in this embodiment is YbCl3, and a single-layer WS2 film is doped with Yb.

[0062] It should be understood that the ratio of the transition metal source to the doping metal source can be adjusted accordingly according to specific needs and is not specifically limited in this embodiment. Furthermore, the doping metal source and solvent are not limited to the above materials. The doping metal sources listed above are water-soluble doping sources, so ultrapure water is selected as the solvent.

[0063] It should also be noted that there is no clear order between step S1 and step S2 in this embodiment, and the above steps only need to be completed before thin film growth.

[0064] S3. Combination Figure 3a As shown, the precursor solution is spin-coated onto the substrate to form a precursor film on the substrate.

[0065] In this step, the spin coating rate of the precursor solution is 7000 r / min to 9000 r / min.

[0066] Specifically, in this embodiment, a sapphire substrate with steps is first placed on a spin coater, and the precursor solution is spin-coated onto the sapphire substrate at a spin coating rate of 8000 r / min, so that the precursor solution is evenly dispersed on the sapphire substrate to form a precursor film.

[0067] S4. Combination Figure 3b As shown, a non-metallic source and a substrate with a precursor film prepared on the surface are placed in a tube furnace, and the tube furnace is heated to form a metal-doped two-dimensional transition metal dichalcogenide film on the surface of the substrate.

[0068] In this embodiment, the non-metallic source is sulfur powder, and the tube furnace is a multi-temperature-zone tube furnace. The multi-temperature-zone tube furnace includes a first temperature zone located upstream and a second temperature zone located downstream, with the temperature of the second temperature zone being higher than that of the first temperature zone. During the preparation process, the non-metallic source is placed in the first temperature zone, and the substrate with the precursor film prepared on its surface is placed in the second temperature zone.

[0069] Specifically, this step includes the following steps:

[0070] 1. Evacuate the multi-temperature zone tubular furnace and repeatedly introduce argon gas for purge to exhaust all the air in the multi-temperature zone tubular furnace.

[0071] In this embodiment, a vacuum pump is used to evacuate the vacuum degree in the multi-temperature zone tubular furnace to below 1 Pa, and 500 sccm of argon gas is repeatedly introduced for purge to exhaust all the air in the multi-temperature zone tubular furnace.

[0072] 2. The multi-temperature zone tubular furnace is heated, and argon and hydrogen are continuously mixed and introduced as transport and protective gases during the heating process to form a metal-doped single-layer two-dimensional transition metal dichalcogenide film on the substrate surface.

[0073] The heating of the multi-temperature zone tubular furnace specifically includes:

[0074] Raise the temperature of the first temperature zone to 150°C to 300°C, preferably to 200°C, and raise the temperature of the second temperature zone to 780°C to 820°C;

[0075] After heating, keep warm for 5 to 15 minutes, preferably 10 minutes;

[0076] Allow the multi-temperature zone tube furnace to cool naturally to room temperature.

[0077] During the entire heating process, 50 sccm of argon and 10 sccm of hydrogen were continuously introduced as transport and shielding gases.

[0078] Ginseng Figure 4 Combined with Figure 3bAs shown in the figure, as the temperature in the multi-zone tube furnace increases, we first see self-driven nucleation of seeds composed of doped metal Yb and transition metal W at the step edge. The nuclei then attach to the step edge of the sapphire substrate and spontaneously orientate and nucleate only at the step edge. These nuclei will be fixed to the steps of the sapphire substrate during the subsequent film growth process, providing a stable doping source for the subsequent growth of large-area Yb-doped single-layer WS2 thin films. This reduces the self-purification effect of the WS2 film during the Yb doping process and prevents the Yb-doped metal from sinking to the bottom, thereby enabling controllable and stable doping of the WS2 film. The above-mentioned oriented nucleation process is a spontaneous process. This is because the exposed step edge on the sapphire substrate surface breaks the energy degeneracy and reduces the symmetry of c-sapphire, making the step edge on the sapphire substrate surface have a higher surface energy. Therefore, during the heating process, the nuclei can be spontaneously adsorbed and promoted to move and attach to the step edge in an oriented manner.

[0079] Ginseng Figure 5 、 Figure 6 Combined with Figure 3b As shown in Figure 1, as the film growth continues, the crystal nuclei on the sapphire substrate with steps continue to grow along the edge of the steps. Figure 5 and Figure 6 It can be seen that the Yb-doped single-layer WS2 film grown on the sapphire substrate with steps shows a clear orientation distribution, which is mainly caused by the induction effect of the substrate with steps. Figure 6 The atomic force microscope (AFM) image shows that the growth of the WS2 film starts along the edge of the step.

[0080] In this embodiment, a stable and controllable Yb-doped WS2 film is achieved on the surface of a sapphire substrate with steps through seed self-driven nucleation. As the growth time is further extended, the Yb-doped WS2 film on the substrate surface will gradually grow. That is, the preparation method in this embodiment can achieve the preparation of large-area metal-doped two-dimensional transition metal dichalcogenide films. The area of ​​the metal-doped two-dimensional transition metal dichalcogenide film in this embodiment is 0.1 cm 2 ~1cm 2 .

[0081] Ginseng Figure 7 As shown in the figure, multiple crystal nuclei were observed on the surface of the sapphire substrate. The oriented growth of the crystal nuclei proceeded along the step edges of the substrate surface and eventually spliced ​​into a large-area Yb-doped WS2 film. This provides a new idea for realizing wafer-level controllable doping of two-dimensional transition metal dichalcogenide films in the future.

[0082] Ginseng Figure 8An optical microscope image of a single-layer Yb-doped WS2 film grown in this example is shown. A distinct scratch, several microns wide, can be observed in the center of the image, exposing the stepped sapphire substrate. This contrasts sharply with the surrounding Yb-doped WS2 film. Furthermore, no obvious multilayer formation was observed over a large area, demonstrating the excellent uniformity of the synthesized Yb-doped WS2 film.

[0083] Ginseng Figure 9 The macroscopic image of a Yb-doped WS2 thin film demonstrates the successful synthesis of a 1cm×1cm centimeter-scale Yb-doped WS2 thin film in this example. Compared to the clean white surface of the sapphire substrate, the Yb-doped WS2 thin film grown on the sapphire substrate exhibits a uniform light green color.

[0084] In this example, random points were taken on the large-area Yb-doped WS2 thin film grown, and statistical graphs of the Raman E2g peak half-width and photoluminescence (PL) peak position were obtained. Figure 10 As shown in the figure, by statistically analyzing 100 Raman spectra and 50 PL spectra, the average half-peak width of the E2g peak in the Raman spectrum is 0.3 cm -1 The ultra-low half-peak width proves that the synthesized large-area Yb-doped WS2 film has high crystalline properties, and the average PL peak position of the Yb-doped WS2 film is at 2.05eV. Figure 11 As shown in the figure, the synthesized Yb-doped WS2 film was subjected to a PL mapping test, and no obvious changes were observed in the mapping diagram, which proves that the synthesized Yb-doped WS2 film has good uniformity.

[0085] Example 2:

[0086] The preparation method of the two-dimensional transition metal dichalcogenide film in this embodiment is roughly the same as that in Example 1, except that Co is used to dope the single-layer WS2 film with metal in this embodiment, and the doping metal source is CoCl2.

[0087] Example 3:

[0088] The preparation method of the two-dimensional transition metal dichalcogenide film in this embodiment is roughly the same as that in Example 1, except that Fe is used to dope the single-layer WS2 film with metal in this embodiment, and the doping metal source is FeCl3.

[0089] Example 4:

[0090] The preparation method of the two-dimensional transition metal dichalcogenide film in this embodiment is roughly the same as that in Example 1, except that Ni is used to dope the single-layer WS2 film with metal in this embodiment, and the doping metal source is NiCl2.

[0091] Example 5:

[0092] The preparation method of the two-dimensional transition metal dichalcogenide film in this embodiment is roughly the same as that in Example 1, except that in this embodiment, Mn is used to metal-dope the single-layer WS2 film, and the doping metal source is MnCl2.

[0093] Example 6:

[0094] The preparation method of the two-dimensional transition metal dichalcogenide film in this embodiment is roughly the same as that in Example 1, except that in this embodiment, Cr is used to metal-dope the single-layer WS2 film, and the doping metal source is CrCl2.

[0095] Comparative Example 1:

[0096] In this comparative example, an intrinsic WS2 thin film was prepared by conventional methods without metal doping.

[0097] Ginseng Figure 12 As shown in the figure, compared with the intrinsic WS2 film, the Yb-doped single-layer WS2 film has a significant Raman characteristic peak shift. The Yb-doped WS2 film has a significant red shift compared with the intrinsic WS2 film, but the A1g peak has almost no red shift.

[0098] Ginseng Figure 13a As shown in Figure 1, a clear Yb peak was observed at 187eV, proving that the Yb metal element was successfully doped into the single-layer WS2 film in Example 1. Figure 13b As shown in Figure 3, the W peak after doping has an obvious red shift, indicating that Yb doping makes the Fermi level closer to the conduction band minimum.

[0099] The present invention uses a wet transfer method to transfer the intrinsic WS2 film in Comparative Example 1 and the Yb-doped WS2 film in Example 1 to a copper mesh and conducts a scanning transmission electron microscope (STEM) test to determine the doping status of metal atoms at the atomic level. Figure 14 As shown in the figure, no obvious atomic intensity fluctuations were observed in the undoped intrinsic WS2 film, which is significantly different from the Yb-doped WS2 film under doping conditions. Under Yb doping, the difference in atomic intensity will show a significant height difference, which also proves that the present invention successfully prepared the Yb-doped WS2 film. Figure 14As shown, no obvious defects were observed in the STEM image of the Yb-doped WS2 film, proving that the preparation method of the present invention can synthesize high-quality metal-doped single-layer two-dimensional transition metal dichalcogenide films.

[0100] In order to verify the universality of the preparation method of the two-dimensional transition metal dichalcogenide thin film in the present invention, the present invention uses different doping metal sources (CoCl2, FeCl3, NiCl2, MnCl2, CrCl2) to prepare precursor solutions doped with different metal types, and prepares single-layer WS2 thin films doped with different metals, namely, the metal-doped single-layer two-dimensional transition metal dichalcogenide thin films prepared in Example 2, Example 3, Example 4, Example 5, and Example 6. Figure 15 As shown, the single-layer WS2 films doped with different metals all exhibited step-induced oriented growth, and no multilayer regions were observed on the substrate surface, proving that the preparation method of the two-dimensional transition metal dichalcogenide film in the present invention can prepare high-quality single-layer doped WS2 films and is universal.

[0101] Ginseng Figure 16 As shown in Figure 1, the Raman spectra of the films prepared in Comparative Example 1, Example 2, Example 3, Example 4, Example 5, and Example 6 are compared. Compared with the intrinsic WS2 film in Comparative Example 1, the E2g peaks of the metal-doped single-layer WS2 films in Examples 2, 3, 4, 5, and 6 all show a significant red shift due to the introduction of doped metal atoms.

[0102] Ginseng Figure 17 As shown in Figure 1, the photoluminescence spectra of the thin films prepared in Comparative Example 1, Example 2, Example 3, Example 4, Example 5, and Example 6 are compared. Compared with the intrinsic WS2 thin film in Comparative Example 1, the metal-doped single-layer WS2 thin films in Examples 2, 3, 4, 5, and 6 all show a significant red shift due to the introduction of doped metal atoms. This may be due to the defect states and spin polarization induced between the conduction band and the valence band due to the introduction of doped metal atoms.

[0103] It can be seen from the above technical solution that the present invention has the following beneficial effects:

[0104] The present invention mixes a doping metal source and a transition metal source to form a precursor solution, and uses a stepped substrate for thin film growth. This solves the problem of difficulty in doping due to the self-purification effect of the material during the doping process, ensures a stable supply of the doping metal source during the metal doping process of the two-dimensional transition metal dichalcogenide film, and achieves stable and controllable doping of the two-dimensional transition metal dichalcogenide film.

[0105] The present invention utilizes the high surface energy effect of the step edge on the substrate surface to promote the spontaneous movement, adsorption and nucleation of crystal seeds, thereby realizing the controllable growth of crystal nuclei. In addition, the orientation of the steps on the substrate surface can induce the oriented growth of metal-doped two-dimensional transition metal dichalcogenide films, thereby realizing the growth of centimeter-scale single-layer metal-doped two-dimensional transition metal dichalcogenide films.

[0106] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0107] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for preparing a two-dimensional transition metal dichalcogenide thin film, characterized in that: The preparation method comprises the following steps: Providing a substrate and performing surface treatment on the substrate to form steps with uniform orientation exposed on the surface of the substrate; dissolving a transition metal source and a doping metal source in a solvent to obtain a precursor solution; spin-coating the precursor solution onto the substrate to form a precursor film on the substrate; A non-metallic source and a substrate with a precursor film prepared on the surface are placed in a tube furnace, and the tube furnace is heated to form a metal-doped two-dimensional transition metal dichalcogenide film on the surface of the substrate.

2. The method for preparing a two-dimensional transition metal dichalcogenide thin film according to claim 1, wherein: The area of ​​the metal-doped two-dimensional transition metal dichalcogenide film is 0.1 cm 2 ~1cm 2 .

3. The method for preparing a two-dimensional transition metal dichalcogenide thin film according to claim 1, wherein: The step height of the substrate surface is 0.5 nm to 1 nm.

4. The method for preparing a two-dimensional transition metal dichalcogenide thin film according to claim 1, wherein: The transition metal element is one or more of W and Mo, the doping metal element is one or more of Yb, Fe, Co, Ni, Mn, and Cr, and the chalcogenide element is one or more of S, Se, and Te.

5. The method for preparing a two-dimensional transition metal dichalcogenide thin film according to claim 4, characterized in that: The two-dimensional transition metal dichalcogenide film is a single-layer WS2 film, the transition metal source is sodium tungstate powder, the doping metal source is one or more of YbCl3, FeCl3, CoCl2, NiCl2, MnCl2, CrCl2, and the non-metallic source is sulfur powder.

6. The method for preparing a two-dimensional transition metal dichalcogenide thin film according to claim 1, wherein: In the step of spin-coating the precursor solution onto the substrate, the spin-coating rate of the precursor solution is 7000 r / min to 9000 r / min.

7. The method for preparing a two-dimensional transition metal dichalcogenide thin film according to claim 1, wherein: The tubular furnace is a multi-temperature zone tubular furnace, which includes a first temperature zone located upstream and a second temperature zone located downstream. The temperature of the second temperature zone is greater than the temperature of the first temperature zone. The non-metallic source is placed in the first temperature zone, and the substrate with a precursor film prepared on the surface is placed in the second temperature zone.

8. The method for preparing a two-dimensional transition metal dichalcogenide thin film according to claim 7, characterized in that: Heating the tube furnace specifically includes: Raise the temperature of the first temperature zone to 150°C to 300°C, and raise the temperature of the second temperature zone to 780°C to 820°C; After heating, keep warm for 5 to 15 minutes; Allow the multi-temperature zone tube furnace to cool naturally to room temperature.

9. The method for preparing a two-dimensional transition metal dichalcogenide thin film according to claim 1, wherein: The heating process of the tube furnace also includes: continuously mixing and introducing argon and hydrogen as transport and protective gases.

10. The method for preparing a two-dimensional transition metal dichalcogenide thin film according to claim 1, wherein: Before heating the tube furnace, it also includes: The tubular furnace was evacuated and argon gas was repeatedly introduced for purge to exhaust the air in the tubular furnace.

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