Method for the gold catalyst particle assisted preparation of transition metal chalcogenide heterostructure nanotubes

Abstract

The application provides a gold catalyst particle assisted chemical vapor deposition method for realizing controllable growth of transition metal chalcogenide heterojunction nanotubes, gold nanometer particle modified silicon wafers with adjustable and uniform distribution diameters can be obtained through magnetron sputtering of gold nanometer films and high temperature annealing treatment, and the silicon wafers are used as growth substrates. In the high temperature reaction process of the chemical vapor deposition, the ratio and evaporation rate of transition metal oxide powder, sulfur powder and selenium powder and the flow and ratio of hydrogen and argon are further precisely controlled through a single / two-temperature zone high temperature furnace, and finally controllable growth of high crystal quality transition metal chalcogenide heterojunction nanotubes can be realized. Further, by controlling the temperature of the growth substrate, the type of the evaporation precursor and the evaporation rate, the growth process of the transition metal chalcogenide nanotubes can be significantly affected, and transition metal chalcogenide heterojunction nanotubes with different structural characteristics such as composition and chirality can be obtained, that is, controllable growth and directional regulation of the physical properties of the transition metal chalcogenide heterojunction nanotubes are realized.

Description

Technical Field

[0001] This invention relates to a method for preparing transition metal chalcogenide heterojunction nanotubes. The controlled growth of transition metal chalcogenide heterojunction nanotubes is achieved via a chemical vapor deposition method catalyzed by gold nanoparticles. Background Technology

[0002] With the continuous development of the preparation and structural control of two-dimensional transition metal chalcogenide (TMD) materials, the study of heterojunctions has attracted increasing attention. These heterojunctions, composed of stacked TMDs of different types, exhibit rich physical properties, further promoting the research on TMD properties and the exploration of novel device applications. Against this backdrop, breaking through traditional TMD structure construction and control strategies and finding new research approaches has become key to advancing the research of transition metal chalcogenide heterojunctions.

[0003] Transition metal chalcogenide heterojunction nanotubes can be viewed as one-dimensional TMD heterostructures formed by nesting different TMD nanotubes. Compared to two-dimensional TMD heterojunctions, one-dimensional TMD heterojunction nanotubes have lower dimensionality, smaller Coulomb shielding effect, additional bending degrees of freedom, and richer chiral structures, which will enrich the structural control mechanisms of TMD heterojunctions and generate more novel physical properties and applications.

[0004] In 2021, scientists at the University of Tokyo in Japan successfully constructed TMD heterojunction nanotubes using a chemical vapor deposition method based on carbon nanotubes as templates [Science 367, 537–542 (2020)]. However, this preparation method has two drawbacks: 1. The preparation process uses carbon nanotubes as templates, increasing the difficulty and uncertainty of controllable preparation; 2. In the prepared TMD heterojunction nanotubes, carbon nanotubes are relatively stable and are good conductive materials, making them difficult to remove, which limits further optical and electrical research on TMD heterojunction nanotubes. How to obtain relatively pure TMD heterojunction nanotubes through a simpler and more controllable preparation process is fundamental to further research.

[0005] Therefore, developing a simple and effective method for preparing pure TMD heterojunction nanotubes, and gaining a deeper understanding of their physical mechanisms to achieve targeted control over the structure of TMD heterojunction nanotubes, will open new avenues for the research and practical application of transition metal chalcogenide heterojunctions. This will promote the widespread application of transition metal chalcogenide heterojunctions in future electronic and optoelectronic devices, providing an important foundation for the exploration of novel functional materials. Summary of the Invention

[0006] The technical problem this invention aims to solve is to provide a gold catalyst-assisted chemical vapor deposition method for the controllable growth of various transition metal chalcogenide (TMD) heterojunction nanotubes and the fine control over parameters such as composition, number of layers, and diameter of these nanotubes. This preparation method utilizes a gold catalyst-assisted chemical vapor deposition process. A gold nanoparticle catalyst is obtained by depositing a gold film on a silicon substrate using magnetron sputtering and then annealing it. This catalyst is then used as the growth substrate, and TMD heterojunction nanotubes are grown under an inert atmosphere and at a specific temperature (as shown in the figure). This yields TMD heterojunction nanotubes with uniform diameter, controllable diameter, and adjustable composition and number of layers for both internal and external TMD nanotubes, meeting the requirements for high crystal quality, high yield, and controllable chirality.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] This invention provides a gold catalyst particle-assisted preparation method for the controllable growth of heterojunction nanotubes of various transition metal chalcogenides. The catalyst is composed of gold particles. By controlling the thickness of the magnetron sputtering coating and the annealing temperature and time, gold nanoparticle catalysts with high catalytic activity of different diameters can be formed after annealing. The preparation steps are as follows:

[0009] S1: Using high-purity gold as the sputtering target and silicon wafer as the sputtering substrate, sputtering was performed for 35 seconds at 100°C and DC power of 50W to obtain a gold film with a uniform thickness of 10nm.

[0010] S2: The gold film obtained by magnetron sputtering is placed in a high-temperature tube furnace for annealing. During the heating stage, the temperature is increased from 25°C to 750°C in 40 minutes. During the isothermal stage, the temperature is maintained at 750°C for 10 minutes. During the cooling stage, the temperature is reduced to 25°C in 10 minutes to obtain a gold nanoparticle catalyst with high catalytic activity and uniform particle diameter. The silicon wafer with gold nanoparticles is then placed on a cuboid sample stage.

[0011] S3: Weigh the transition metal oxide and the two chalcogen element powders separately using a quartz boat. Spread the transition metal oxide evenly on the quartz boat and place the chalcogen element powder on the feeding device.

[0012] S4: Place the transition metal oxides and chalcogenide powders obtained in S3 into specific areas of a high-temperature tube furnace, and set specific heating zones and heating temperatures.

[0013] S5: Set a specific heating zone and heating temperature. When the temperature reaches a certain specific temperature, a certain amount of hydrogen and nitrogen mixed gas is introduced. At the same time, the chalcogen element powder is slowly fed into the heating zone by the feeding device to make it reach the initial melting state. The chalcogen element powder is then uniformly pushed forward within a certain time until it is completely evaporated.

[0014] S6: After the heat preservation time is over, stop the heat preservation and allow it to cool naturally to 25°C. Remove the sample stage to obtain the finished product.

[0015] Furthermore, the feeding device includes a magnetic base and a magnet. Chalcogen element powder is placed on the magnetic base, and the magnet is located outside the high-temperature tube furnace. By moving the magnet, the magnetic base inside the high-temperature tube furnace is moved.

[0016] Furthermore, the metal oxide is tungsten trioxide or molybdenum trioxide, and the chalcogenide powder is one of S and Se.

[0017] Compared with the prior art, this application has the following beneficial effects:

[0018] This invention presents a gold catalyst-assisted preparation method for the controllable growth of transition metal chalcogenide (TMC) heterojunction nanotubes. The method utilizes magnetron sputtering and annealing to prepare highly active gold nanoparticle catalysts with excellent high-temperature stability. The preparation method is simple, achieving controllable growth of TMC heterojunction nanotubes and yielding relatively uniform TMC heterojunction nanotubes. Furthermore, the ability to control the growth substrate temperature allows for precise adjustment of the TMC heterojunction nanotube diameter and number of layers. These novel TMC heterojunction nanotubes hold immense research and application potential in electronic and optoelectronic devices. Attached Figure Description

[0019] Figure 1 SEM image of gold nanoparticles formed on a silicon wafer provided by the present invention;

[0020] Figure 2 SEM image of transition metal chalcogenide heterojunction nanotubes provided by the present invention; Detailed Implementation

[0021] The invention will now be described in further detail with reference to specific examples. However, the scope of implementation is not limited to the examples provided.

[0022] Example 1:

[0023] A method for preparing heterojunction nanotubes with an inner tube of tungsten selenide and an outer tube of tungsten sulfide is provided. This method consists of two parts: the preparation of a gold nanoparticle catalyst and chemical vapor deposition growth. The preparation steps are as follows:

[0024] S1: Using high-purity gold as the sputtering target and silicon wafer as the sputtering substrate, sputtering was performed for 35 seconds at 100°C and DC power of 50W to obtain a gold film with a uniform thickness of 10nm.

[0025] S2: The gold film obtained by magnetron sputtering is placed in a high-temperature tube furnace for annealing. The temperature is first raised from 25°C to 750°C over 40 minutes, then held at 750°C for 10 minutes, and finally lowered to 25°C over 10 minutes to obtain gold nanoparticle catalysts with high catalytic activity and uniform particle diameter on the silicon wafer. The silicon wafer with gold nanoparticles is then placed on a cuboid sample stage.

[0026] S3: Weigh 0.45g of nano tungsten trioxide (Nanopower<200nm, 99.9% metal-based), 0.3g of sublimed sulfur (>99.5%), and 0.4g of selenium powder (>99.5%) using a quartz boat (15*100). Spread the tungsten trioxide evenly on the quartz boat, place the sulfur powder on the sulfur powder feeding device, and place the selenium powder on the selenium powder feeding device.

[0027] S4: Place the quartz boat containing tungsten trioxide in the center of the single-temperature zone high-temperature tube furnace, place the sample stage in the heating zone of the tube furnace, and place the sulfur powder feeding device and selenium powder feeding device in the non-heating zone on the left side of the high-temperature tube furnace.

[0028] S5: Heat the high-temperature tubular furnace, raising the temperature from 25℃ to 900℃ within 40 minutes. When the temperature reaches 900℃, introduce 10 sccm of hydrogen and 150 sccm of argon gas from the left side of the high-temperature tubular furnace, and adjust the gas pressure of the high-temperature tubular furnace to maintain a constant low pressure. Then continue to raise the temperature to 985℃ within 4 minutes, and maintain it at 985℃ for 15 minutes. When the temperature reaches 900℃, use the selenium powder feeding device to slowly feed the selenium powder into the left side of the heating zone of the tubular furnace to make it reach the initial melting state. When the temperature reaches 985℃, start to push the selenium powder evenly into the heating zone within 7 minutes, and then push the sulfur powder evenly into the heating zone. In the next 8 minutes, evaporate all the sulfur powder.

[0029] S6: After the heat preservation time is over, stop the heat preservation and allow it to cool naturally to 25°C. Remove the sample stage to obtain the finished product.

[0030] Example 2

[0031] A method for preparing heterojunction nanotubes with an inner molybdenum sulfide tube and an outer molybdenum selenide tube is provided. This method consists of two parts: the preparation of gold nanoparticle catalysts and chemical vapor deposition growth. The preparation steps are as follows:

[0032] S1: Using high-purity gold as the sputtering target and silicon wafer as the sputtering substrate, sputtering was performed for 35 seconds at 100°C and DC power of 50W to obtain a gold film with a uniform thickness of 10nm.

[0033] S2: The gold film obtained by magnetron sputtering is placed in a high-temperature tube furnace for annealing. The temperature is first raised from 25°C to 750°C over 40 minutes, then held at 750°C for 10 minutes, and finally lowered to 25°C over 10 minutes to obtain gold nanoparticle catalysts with high catalytic activity and uniform particle diameter on the silicon wafer. The silicon wafer with gold nanoparticles is then placed on a cuboid sample stage.

[0034] S3: Weigh 0.5g of nano molybdenum trioxide (Nanopower<200nm, 99.9% metal-based), 0.3g of selenium powder (>99.5%), and 0.4g of sublimed sulfur (>99.5%) using a quartz boat (15*100). Spread tungsten trioxide evenly on the quartz boat, place the selenium powder at the front of the feeding device, and place the sulfur powder at the rear of the feeding device, with a certain distance between the sulfur powder and the selenium powder.

[0035] S4: Place the quartz boat containing molybdenum trioxide in the center of the left temperature zone of the high-temperature tube furnace, place the sample stage in the right temperature zone of the tube furnace, and place the feeding device in the non-heating zone on the right side of the high-temperature tube furnace.

[0036] S5: First, heat the right temperature zone of the high-temperature tubular furnace from 25°C to 900°C within 40 minutes. After 20 minutes of heating the right zone, start heating the left zone, raising the center temperature of the left zone from 25°C to 510°C within 20 minutes. When the left zone reaches 510°C and the right zone reaches 900°C, introduce 13 sccm of hydrogen and 150 sccm of argon gas from the left side of the furnace, adjusting the furnace pressure to maintain a constant low pressure. Then continue heating the left and right zones within 4 minutes. The left temperature zone is heated to 580℃ and maintained at 580℃ for 15 minutes. Simultaneously, the right temperature zone is heated to 985℃ within 5 minutes and maintained at 985℃ for 15 minutes. When the temperature of the right temperature zone reaches 900℃, the selenium powder is slowly fed into the right side of the right temperature zone using a feeding device to bring it to an initial melting state. When the temperature reaches 985℃, the selenium powder on the feeding device is evenly fed into the right temperature zone within 7 minutes. When the selenium powder has evaporated completely, the sulfur powder on the feeding device is continued to be fed into the right temperature zone. The sulfur powder is then completely evaporated within the next 8 minutes.

[0037] S6: After the left temperature zone's heat preservation time ends, stop the heat preservation and allow it to cool naturally to 25℃. After the right temperature zone's heat preservation time ends, stop the heat preservation and allow it to cool naturally to 25℃. Remove the sample stage to obtain the finished product.

[0038] The finished product was taken out, and the SEM and TEM test results showed that the grown heterojunction nanotubes had uniform diameter and controllable number of layers, meeting the requirements for high-quality and large-scale growth.

Claims

1. A method for preparing an inner tube tungsten selenide / outer tube tungsten sulfide heterojunction nanotube, the method comprising two parts: preparation of a gold nanoparticle catalyst and chemical vapor deposition growth, characterized in that, The preparation steps are as follows: S1: Using high-purity gold as the sputtering target and silicon wafer as the sputtering substrate, sputtering was performed for 35 seconds at 100°C and DC power of 50W to obtain a gold film with a uniform thickness of 10nm. S2: The gold film obtained by magnetron sputtering is placed in a high-temperature tube furnace for annealing. The temperature is first raised from 25°C to 750°C over 40 minutes, then held at 750°C for 10 minutes, and finally lowered to 25°C over 10 minutes to obtain gold nanoparticle catalysts with high catalytic activity and uniform particle diameter on the silicon wafer. The silicon wafer with gold nanoparticles is then placed on a cuboid sample stage. S3: Weigh 0.45g of nano tungsten trioxide, 0.3g of sublimed sulfur, and 0.4g of selenium powder using a quartz boat. Spread the tungsten trioxide evenly on the quartz boat, place the sulfur powder on the sulfur powder feeding device, and place the selenium powder on the selenium powder feeding device. S4: Place the quartz boat containing tungsten trioxide in the center of the single-temperature zone high-temperature tube furnace, place the sample stage in the heating zone of the tube furnace, and place the sulfur powder feeding device and selenium powder feeding device in the non-heating zone on the left side of the high-temperature tube furnace. S5: Heat the high-temperature tubular furnace, raising the temperature from 25℃ to 900℃ within 40 minutes. When the temperature reaches 900℃, introduce 10 sccm of hydrogen and 150 sccm of argon gas from the left side of the high-temperature tubular furnace, and adjust the gas pressure of the high-temperature tubular furnace to maintain a constant low pressure. Then continue to raise the temperature to 985℃ within 4 minutes, and maintain it at 985℃ for 15 minutes. When the temperature reaches 900℃, use the selenium powder feeding device to slowly feed the selenium powder into the left side of the heating zone of the tubular furnace to make it reach the initial melting state. When the temperature reaches 985℃, start to push the selenium powder evenly into the heating zone within 7 minutes, and then push the sulfur powder evenly into the heating zone. In the next 8 minutes, evaporate all the sulfur powder. S6: After the heat preservation time is over, stop the heat preservation and allow it to cool naturally to 25°C. Remove the sample stage to obtain the finished product.

2. A method for preparing an inner molybdenum sulfide / outer molybdenum selenide heterojunction nanotube, characterized in that, The preparation method consists of two parts: the preparation of gold nanoparticle catalysts and chemical vapor deposition growth. The preparation steps are as follows: S1: Using high-purity gold as the sputtering target and silicon wafer as the sputtering substrate, sputtering was performed for 35 seconds at 100°C and DC power of 50W to obtain a gold film with a uniform thickness of 10nm. S2: The gold film obtained by magnetron sputtering is placed in a high-temperature tube furnace for annealing. The temperature is first raised from 25°C to 750°C over 40 minutes, then held at 750°C for 10 minutes, and finally lowered to 25°C over 10 minutes to obtain gold nanoparticle catalysts with high catalytic activity and uniform particle diameter on the silicon wafer. The silicon wafer with gold nanoparticles is then placed on a cuboid sample stage. S3: Weigh 0.5g of nano molybdenum trioxide, 0.3g of selenium powder, and 0.4g of sublimed sulfur using a quartz boat. Spread the molybdenum trioxide evenly on the quartz boat, place the selenium powder at the front of the feeding device, and place the sulfur powder at the rear of the feeding device, with a certain distance between the sulfur powder and the selenium powder. S4: Place the quartz boat containing molybdenum trioxide in the center of the left temperature zone of the high-temperature tube furnace, place the sample stage in the right temperature zone of the tube furnace, and place the feeding device in the non-heating zone on the right side of the high-temperature tube furnace. S5: First, heat the right temperature zone of the high-temperature tubular furnace from 25°C to 900°C within 40 minutes. After 20 minutes of heating in the right zone, start heating the left zone, raising the center temperature of the left zone from 25°C to 510°C within 20 minutes. When the left zone reaches 510°C and the right zone reaches 900°C, introduce 13 sccm of hydrogen and 150 sccm of argon gas from the left side of the furnace, adjusting the furnace pressure to maintain a constant low pressure. Then continue heating the left and right zones, increasing the temperature by 4 minutes... The left heating zone is heated to 580℃ and maintained at 580℃ for 15 minutes. While the left heating zone is heating up, the right heating zone is heated to 985℃ within 5 minutes and maintained at 985℃ for 15 minutes. When the temperature of the right heating zone reaches 900℃, the selenium powder is slowly fed into the right heating zone using a feeding device to bring it to an initial melting state. When the temperature reaches 985℃, the selenium powder on the feeding device is evenly fed into the heating zone within 7 minutes. When the selenium powder has evaporated completely, the sulfur powder on the feeding device is continued to be fed into the heating zone. The sulfur powder is completely evaporated within the next 8 minutes. S6: After the left temperature zone's heat preservation time ends, stop the heat preservation and allow it to cool naturally to 25℃. After the right temperature zone's heat preservation time ends, stop the heat preservation and allow it to cool naturally to 25℃. Remove the sample stage to obtain the finished product.

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