A multilayer corner transition metal chalcogenide and preparation method thereof

Abstract

The present invention relates to a multilayer corner transition metal chalcogenide and a preparation method thereof, comprising the following steps: in an argon / hydrogen atmosphere, heating a sulfur source, a transition metal oxide and a 300nm silicon oxide / silicon substrate spin-coated with silicon oxide nanospheres respectively to generate gaseous sulfur and gaseous transition metal oxide, reacting the gaseous sulfur and the gaseous transition metal oxide, and depositing the multilayer corner transition metal chalcogenide on the 300nm silicon oxide / silicon substrate by using the silicon oxide nanospheres as nucleation points at the initial stage of the reaction. Compared with the prior art, in the multilayer corner transition metal chalcogenide prepared by the present invention, each adjacent two layers of the transition metal chalcogenide have an interlayer corner angle of any angle within the range of 0° to 60°, and at least two interlayer corner angles are unequal in angle, and the multilayer corner transition metal chalcogenide with more layers and more random corners has novel physical phenomena, and can provide samples and test possibilities for studying corner systems.

Description

Technical Field

[0001] The invention relates to the technical field of two-dimensional layered nanomaterial preparation, and in particular to a multilayer corner transition metal sulfide compound and a preparation method thereof. Background Art

[0002] As a new type of nanomaterial, two-dimensional materials not only have inherent advantages in size and structure, but also are affected by the type of atoms and lattice arrangement, which makes different two-dimensional materials show different properties. As a type of two-dimensional material, transition metal dichalcogenides (TMDs) have attracted much attention. They show a wide range of unique electrical, optical, thermal and mechanical properties; electronic and optoelectronic components made of TMDs materials, such as field effect transistors, sensors and photodetectors, are potential substitutes for silicon in traditional electronics and potential substitutes for organic semiconductors in wearable and flexible systems. Multilayer corner TMDs are a type of material composed of multiple layers of transition metal dichalcogenides stacked vertically by rotating a certain angle. In this structure, the stacking angle between multilayer TMDs is usually different from the ideal structure of vertical stacking, but there is a certain rotation angle. This non-ideal multilayer structure will cause significant changes in the electronic structure and optical properties of the material, and has unique physical properties. At a specific rotation angle, the interaction between electrons will increase, causing the electronic behavior and properties of the material to be strongly affected by the correlation effect, resulting in novel physical states such as correlated insulating state, quantum spin liquid state, anomalous quantum Hall state, and spin Hall state. At the same time, due to its special structure and properties, multilayer angle-rotated TMDs can exhibit excellent optical absorption and emission properties, and are suitable for optoelectronic devices, sensors, and photocatalysis.

[0003] At present, the methods for preparing multilayer corner TMDs are mainly mechanical exfoliation and chemical vapor deposition. Among them, the mechanical exfoliation method requires first obtaining a single layer of transition metal sulfide by mechanical exfoliation, and then stacking the single layer of transition metal sulfide by fixed-point transfer. Its preparation process is complicated and the yield is low. During the stacking process, stress or gaps will be formed between the layers of the multilayer corner TMDs, which limits the research on multilayer corner TMDs. Therefore, chemical vapor deposition is usually used to directly prepare multilayer corner TMDs, but due to the influence of interlayer interactions, the multilayer corner TMDs prepared by chemical vapor deposition are usually double-layer, and the interlayer angle is usually thermodynamically stable 0° (AA stacking) or 60° (AB stacking). It is almost difficult to achieve stacking at other angles, which limits the structure of multilayer corner TMDs and thus limits the research on corner systems. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing a multilayer corner transition metal chalcogenide compound, so as to provide samples and testing possibilities for studying corner systems.

[0005] A method for preparing a multilayer corner transition metal chalcogenide compound comprises the following steps:

[0006] In an argon / hydrogen atmosphere, a sulfur source, a transition metal oxide, and a 300nm silicon oxide / silicon substrate silicon oxide nanosphere spin-coated with silicon oxide nanospheres are heated respectively to generate gaseous sulfur and gaseous transition metal oxides, and the gaseous sulfur and gaseous transition metal oxides are reacted with the silicon oxide nanospheres, and the silicon oxide nanospheres are used as nucleation points in the initial stage of the reaction to deposit on the 300nm silicon oxide / silicon substrate to obtain a multilayer corner transition metal chalcogenide. Compared with the prior art, in the multilayer corner transition metal chalcogenide prepared by the method of the present invention, each adjacent two layers of the transition metal chalcogenide have an interlayer corner angle of any angle within the range of 0° to 60°, and at least two interlayer corner angles are unequal, and the multilayer corner transition metal chalcogenide with more layers and more random corners has novel physical phenomena, which can provide samples and test possibilities for studying corner systems.

[0007] Furthermore, the particle size of the silicon oxide nanospheres is 10nm~500nm.

[0008] Furthermore, the sulfur source is sulfur powder; and the transition metal oxide includes tungsten trioxide and sodium chloride.

[0009] Furthermore, the pressure of the argon atmosphere is 120-180 Pa.

[0010] Furthermore, the sulfur source is heated to 140-200° C., the transition metal oxide is heated to 650-750° C., and the SiO 2 / Si substrate spin-coated with silicon oxide nanospheres is heated to 800-900° C.

[0011] Furthermore, the mass ratio of the sulfur source, tungsten trioxide and sodium chloride is 7~10:5:5~1.

[0012] Furthermore, the reaction time is 5 to 20 minutes, and the carrier gases used to react the gaseous sulfur and the gaseous transition metal oxide with the silicon oxide nanospheres are argon and hydrogen, and the flow ratio of argon to hydrogen is 10:1.

[0013] The present invention also provides a multilayer corner transition metal sulfide compound, which is formed by stacking at least three layers of transition metal sulfide compounds, wherein a corner exists between every two adjacent layers of transition metal sulfide compounds, and the torsion angles of at least two corners are different.

[0014] Furthermore, the torsion angle of the corner is any angle between 0° and 60°.

[0015] Furthermore, the transition metal chalcogenide is tungsten disulfide.

[0016] Furthermore, the tungsten disulfide contains silicon oxide nanospheres. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the equipment used in the present invention and its operation.

[0018] Figure 2 Schematic diagram of the multilayer corner tungsten disulfide prepared in Example 1 of the present invention and its number of layers.

[0019] Figure 3 This is an optical image of the multilayer corner tungsten disulfide prepared in Example 1 of the present invention.

[0020] Figure 4 for Figure 3 Second harmonic imaging of multilayer corner tungsten disulfide.

[0021] Figure 5 This is a single layer of tungsten disulfide prepared in the comparative example of the present invention. DETAILED DESCRIPTION

[0022] In order to solve the problem that the multilayer corner TMDs material prepared by the existing chemical vapor deposition method has a small number of layers, a fixed angle between layers, and the angle is usually 0° or 60° which is thermodynamically stable, the present invention uses different reagents and different nanoparticles to pretreat the SiO2 / Si substrate, and finally finds that silicon oxide nanoparticles are helpful for the formation of multilayer corner transition metal chalcogenides. Based on this, the present invention provides a method for preparing a multilayer corner transition metal chalcogenide, comprising the following steps:

[0023] In an argon / hydrogen atmosphere, a sulfur source, a transition metal oxide, and a 300nm silicon oxide / silicon substrate silicon oxide nanospheres spin-coated with silicon oxide nanospheres are heated respectively to generate gaseous sulfur and gaseous transition metal oxides, which are reacted with the silicon oxide nanospheres, and multilayer corner transition metal chalcogenides are deposited on the 300nm silicon oxide / silicon substrate using the silicon oxide nanospheres as nucleation points at the initial stage of the reaction. In which, with argon / hydrogen as carriers, the sulfur source, transition metal oxide, and the SiO2 / Si substrate spin-coated with silicon oxide nanospheres are placed in sequence from upstream to downstream along the carrier gas route, and the carrier gas transports the sulfur source and transition metal oxide heated to the gaseous state to the surface of the SiO2 / Si substrate spin-coated with silicon oxide nanospheres for reaction.

[0024] Each two adjacent layers of the multilayer transition metal sulfide compound prepared by the method have an interlayer rotation angle of any angle within the range of 0° to 60°, and at least two interlayer rotation angles are unequal.

[0025] Specifically, the present invention adopts a three-temperature-zone high-temperature tube furnace to prepare the above-mentioned multilayer corner transition metal chalcogenide compound. The sulfur powder, transition metal oxide powder, and SiO2 / Si substrate spin-coated with silicon oxide nanospheres are placed in sequence from the air inlet end to the air outlet end of the tube furnace. By adjusting the temperature in different temperature zones, multilayer corner transition metal chalcogenide compounds of different sizes can be prepared in one time, which more efficiently provides more samples and more testing possibilities for studying corner systems.

[0026] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0028] The reagents used in the following examples, unless otherwise specified, are all commercially available; the methods used in the following examples, unless otherwise specified, are all achievable by conventional methods.

[0029] Example 1

[0030] This embodiment uses a three-temperature zone high-temperature tube furnace, please refer to Figure 1 The three-zone high-temperature tube furnace includes a first temperature zone, a second temperature zone, and a third temperature zone arranged in sequence in the middle and downstream of the three-zone high-temperature tube furnace, and a heating belt arranged in the upstream of the three-zone high-temperature tube furnace. This embodiment adopts a chemical vapor deposition method to deposit a multilayer corner transition metal chalcogenide, including the following steps:

[0031] S0. Disperse silicon oxide nanospheres with a diameter of 100 nm in ethanol solvent, and after sufficient ultrasonication, spin-coat them on a 300 nm SiO2 / Si substrate.

[0032] S1. Take 0.2g of sulfur powder and place it in No. 1 alumina boat, and place the No. 1 alumina boat upstream of the high-temperature tube furnace, close to the air inlet end of the high-temperature tube furnace, and about 15cm away from the first temperature zone; take a mixture of 0.1g of tungsten trioxide powder and 0.02g of sodium chloride powder and place it in No. 2 alumina boat, and place the No. 2 alumina boat in the first temperature zone of the high-temperature tube furnace, and place the SiO2 / Si substrate with spin-coated silicon oxide nanospheres facing up in the second and third temperature zones of the high-temperature tube furnace.

[0033] S2. Use a vacuum pump to maintain the pressure in the tube furnace at about 150 Pa, and introduce argon as a carrier gas at a flow rate of 50 sccm to exhaust all air.

[0034] S3. Heat the No. 2 alumina boat in the first temperature zone of the tubular furnace, the SiO2 / Si substrate in the second temperature zone, and the SiO2 / Si substrate in the third temperature zone. When the temperature of the No. 2 alumina boat in the first temperature zone rises to 500°C, turn on the heating belt to heat the sulfur powder to 160°C and maintain the temperature.

[0035] S4. While heating the sulfur powder, continue to heat the No. 2 alumina boat in the first temperature zone, the SiO2 / Si substrate in the second temperature zone, and the SiO2 / Si substrate in the third temperature zone until their temperatures simultaneously rise to 700°C, 800°C, and 900°C. Introduce hydrogen at a flow rate of 5 sccm and maintain this growth condition for 10 min.

[0036] S5. After the growth is completed, the heating belt is turned off, the hydrogen is stopped, and the argon gas flow rate is adjusted to 150 sccm. After the tube furnace is naturally cooled to room temperature, a multilayer corner tungsten disulfide is obtained on the SiO2 / Si substrate.

[0037] Among them, 300nm silicon oxide / silicon substrate means that a layer of silicon oxide with a thickness of 300nm is oxidized on a silicon wafer to form a silicon oxide / silicon substrate. In addition, the heating rate of the three-temperature zone high-temperature tube furnace is maintained within 20°C / min. In this embodiment, the three-temperature zone high-temperature tube furnace can simultaneously obtain multilayer corner tungsten disulfide of different sizes, thereby improving the preparation efficiency and providing more samples and test possibilities for the study of the corner system. Among them, the size and number of corners of the multilayer corner tungsten disulfide obtained in the second temperature zone are greater than those of the multilayer corner tungsten disulfide in the third temperature zone.

[0038] In other embodiments, a double-temperature-zone tubular furnace can also be used to prepare multilayer corner tungsten disulfide. In the double-temperature-zone tubular furnace, a mixture of tungsten trioxide powder and sodium chloride powder is placed in a first temperature zone and the temperature of the first temperature zone is controlled to be 700°C, and a SiO2 / Si substrate is placed in a second temperature zone and the temperature of the second temperature zone is controlled to be 800-900°C.

[0039] See also Figures 2~4In this embodiment, a multilayer corner tungsten disulfide is obtained on a SiO2 / Si substrate. The compound has an obvious layered structure with more than two layers. There is an interlayer corner between every two adjacent layers of transition metal sulfide compounds. The angle of the interlayer corner is 0°~60°, and the angle of at least one interlayer corner is not equal to the angles of other interlayer corners.

[0040] Example 2

[0041] In this embodiment, a multilayer corner transition metal chalcogenide is prepared according to the following steps:

[0042] S0. Disperse silicon oxide nanospheres with a diameter of 200 nm in ethanol solvent, and after sufficient ultrasonication, spin-coat them on a quartz plate with a SiO2 / Si substrate.

[0043] S1. Take 0.2g of sulfur powder and place it in No. 1 alumina boat, and place the No. 1 alumina boat upstream of the high-temperature tube furnace, about 15cm away from the first temperature zone; take a mixture of 0.1g of tungsten trioxide powder and 0.02g of sodium chloride powder and place it in No. 2 alumina boat, and place the No. 2 alumina boat in the first temperature zone of the high-temperature tube furnace, and place the SiO2 / Si substrate with spin-coated silicon oxide nanospheres facing up in the second and third temperature zones of the high-temperature tube furnace.

[0044] S2. Use a vacuum pump to maintain the pressure in the tube furnace at about 150 Pa, and introduce argon as a carrier gas at a flow rate of 50 sccm to exhaust all air.

[0045] S3. Heat the No. 2 alumina boat in the first temperature zone, the SiO2 / Si substrate in the second temperature zone, and the SiO2 / Si substrate in the third temperature zone of the tubular furnace. When the temperature of the No. 2 alumina boat in the first temperature zone rises to 500°C, turn on the heating belt to heat the sulfur powder to 150°C and maintain this temperature.

[0046] S4. While heating the sulfur powder, continue to heat the No. 2 alumina boat in the first temperature zone, the SiO2 / Si substrate in the second temperature zone, and the SiO2 / Si substrate in the third temperature zone until their temperatures simultaneously rise to 700°C, 800°C, and 900°C. Introduce hydrogen at a flow rate of 5 sccm and maintain this growth condition for 10 min.

[0047] S5. After the growth is completed, the heating belt is turned off, the hydrogen is stopped, and the argon gas flow rate is adjusted to 150 sccm. After the tube furnace is naturally cooled to room temperature, a multilayer corner tungsten disulfide is obtained on the SiO2 / Si substrate.

[0048] Compared with Example 1, the multilayer corner tungsten disulfide prepared in this example has more layers.

[0049] Example 3

[0050] In this embodiment, a multilayer corner transition metal chalcogenide is prepared according to the following steps:

[0051] S0. Disperse silicon oxide nanospheres with a diameter of 500 nm in ethanol solvent and spin-coat them on a quartz plate with a SiO2 / Si substrate after sufficient ultrasonication.

[0052] S1. Take 0.2g of sulfur powder and place it in No. 1 alumina boat, and place the No. 1 alumina boat upstream of the high-temperature tube furnace, about 15cm away from the first temperature zone; take a mixture of 0.1g of tungsten trioxide powder and 0.02g of sodium chloride powder and place it in No. 2 alumina boat, and place the No. 2 alumina boat in the first temperature zone of the high-temperature tube furnace, and place the SiO2 / Si substrate with spin-coated silicon oxide nanospheres facing up in the second and third temperature zones of the high-temperature tube furnace.

[0053] S2. Use a vacuum pump to maintain the pressure in the tube furnace at about 150 Pa, and introduce argon as a carrier gas at a flow rate of 50 sccm to exhaust all air.

[0054] S3. Heat the No. 2 alumina boat in the first temperature zone of the tubular furnace, the SiO2 / Si substrate in the second temperature zone, and the SiO2 / Si substrate in the third temperature zone. When the temperature of the No. 2 alumina boat in the first temperature zone rises to 500°C, turn on the heating belt to heat the sulfur powder to 160°C and maintain this temperature.

[0055] S4. While heating the sulfur powder, continue to heat the No. 2 alumina boat in the first temperature zone, the SiO2 / Si substrate in the second temperature zone, and the SiO2 / Si substrate in the third temperature zone until their temperatures simultaneously rise to 700°C, 800°C, and 900°C. Introduce hydrogen at a flow rate of 5 sccm and maintain this growth condition for 10 min.

[0056] S5. After the growth is completed, the heating belt is turned off, the hydrogen is stopped, and the argon gas flow rate is adjusted to 150 sccm. After the tube furnace is naturally cooled to room temperature, a multilayer corner tungsten disulfide is obtained on the SiO2 / Si substrate.

[0057] Compared with Examples 1 and 2, the number of layers of the multilayer corner tungsten disulfide prepared in this example is significantly increased, up to 10 layers.

[0058] Comparative Example

[0059] The transition metal chalcogenides were prepared as follows:

[0060] S1. Take 0.2g of sulfur powder and place it in No. 1 alumina boat, and place the No. 1 alumina boat upstream of the high-temperature tube furnace, about 15cm away from the first temperature zone; take a mixture of 0.1g of tungsten trioxide powder and 0.02g of sodium chloride powder and place it in No. 2 alumina boat, and place the No. 2 alumina boat in the first temperature zone of the high-temperature tube furnace, and place the SiO2 / Si substrate face up in the second and third temperature zones of the high-temperature tube furnace.

[0061] S2. Use a vacuum pump to maintain the pressure in the tube furnace at about 150 Pa, and introduce argon as a carrier gas at a flow rate of 50 sccm to exhaust all air.

[0062] S3. Heat the No. 2 alumina boat in the first temperature zone of the tubular furnace, the SiO2 / Si substrate in the second temperature zone, and the SiO2 / Si substrate in the third temperature zone. When the temperature of the No. 2 alumina boat in the first temperature zone rises to 500°C, turn on the heating belt to heat the sulfur powder to 160°C and maintain this temperature.

[0063] S4. While heating the sulfur powder, continue to heat the No. 2 alumina boat in the first temperature zone, the SiO2 / Si substrate in the second temperature zone, and the SiO2 / Si substrate in the third temperature zone until their temperatures simultaneously rise to 700°C, 800°C, and 900°C. Introduce hydrogen at a flow rate of 5 sccm and maintain this growth condition for 10 min.

[0064] S5. After the growth is completed, the heating belt is turned off, the hydrogen is stopped, and the argon gas flow rate is adjusted to 150 sccm. After the tube furnace is naturally cooled to room temperature, a single layer of tungsten disulfide is obtained on the SiO2 / Si substrate.

[0065] The difference between the comparative example and Examples 1 to 3 is that the silicon oxide nanospheres are not spin-coated on the SiO2 / Si substrate, and the other raw materials and steps are the same as those of Examples 1 to 3.

[0066] See also Figure 5 The comparative example can only obtain a single layer of tungsten disulfide compound, which proves that spin coating of silicon oxide nanospheres on SiO2 / Si substrate is helpful to obtain multilayer corner transition metal chalcogenide compounds. In addition, the size of silicon oxide nanospheres affects the torsion angle and the number of layers of the multilayer corner transition metal chalcogenide compounds. The addition of silicon oxide nanospheres can bring random torsion angles to the multilayer corner transition metal chalcogenide compounds. The larger the size of the silicon oxide nanospheres spin coated on the SiO2 / Si substrate, the more random corner layers of the multilayer corner transition metal chalcogenide compounds obtained.

[0067] In summary, the multilayer corner transition metal sulfide prepared by the method for preparing a multilayer corner transition metal sulfide of the present invention can reach up to 10 layers, and the angle range of the corner between the layers is 0°~60°, and the torsion angle between each layer is random, and at least two torsion angles are different. There is no report in the current literature on multilayer corner transition metal sulfide with random corners between each layer. Since the introduction of different numbers of layers and different stacking angles in the multilayer corner transition metal sulfide directly determines the symmetry and interlayer coupling behavior of the two-dimensional atomic crystal, the multilayer corner transition metal sulfide produces various novel physical properties. Therefore, the present invention provides more samples and test possibilities for studying the corner system, and the method of the present invention can synthesize multilayer corner transition metal sulfide of different sizes at one time, with high preparation efficiency, which is conducive to efficiently obtaining more samples and improving the efficiency of testing.

[0068] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a multilayer corner transition metal chalcogenide compound, characterized in that: The steps include: In an argon / hydrogen atmosphere, a sulfur source, a transition metal oxide, and a silicon oxide / silicon substrate spin-coated with silicon oxide nanospheres are heated respectively to generate gaseous sulfur and gaseous transition metal oxides, and the gaseous sulfur and the gaseous transition metal oxides are reacted, and multilayer corner transition metal chalcogenides are deposited on the silicon oxide / silicon substrate by using the silicon oxide nanospheres as nucleation points in the initial stage of the reaction, wherein the particle size of the silicon oxide nanospheres spin-coated on the silicon oxide / silicon substrate is 10nm~500nm.

2. The preparation method according to claim 1, characterized in that: The sulfur source is sulfur powder; the transition metal oxide includes tungsten trioxide and sodium chloride.

3. The preparation method according to claim 2, characterized in that: The pressure of the argon atmosphere is 120~180Pa.

4. The preparation method according to claim 3, characterized in that: The sulfur source is heated to 140-200° C., the transition metal oxide is heated to 650-750° C., and the silicon oxide / silicon substrate spin-coated with silicon oxide nanospheres is heated to 800-900° C.

5. The preparation method according to claim 2, characterized in that: The mass ratio of the sulfur source, tungsten trioxide and sodium chloride is 7-10:5:5-1.

6. The preparation method according to claim 4, characterized in that: The reaction time is 5 to 20 minutes, the carrier gases used are argon and hydrogen, and the flow ratio of argon to hydrogen is 10:

1.

7. The preparation method according to claim 1, characterized in that: The multi-layer corner transition metal sulfide compound is formed by stacking at least three layers of transition metal sulfide compounds, a corner exists between every two adjacent layers of transition metal sulfide compounds, and the torsion angles of at least two corners are different.

8. The preparation method according to claim 7, characterized in that: The torsion angle of the corner is any angle between 0° and 60°.

9. The preparation method according to claim 8, characterized in that: The transition metal chalcogenide is tungsten disulfide.

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