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CN-121976291-A - Method for preparing single-layer tungsten disulfide single-crystal film

CN121976291ACN 121976291 ACN121976291 ACN 121976291ACN-121976291-A

Abstract

The invention relates to a method for preparing a single-layer tungsten disulfide single-crystal film, which adopts a low-pressure chemical vapor deposition method, takes a sapphire substrate with a modification layer containing tungsten elements as a substrate, takes sulfur powder and tungsten trioxide powder as precursor sources, carries out the growth of single-layer single-orientation tungsten disulfide domain areas, and adjusts and controls the growth time of the single-layer single-orientation tungsten disulfide domain areas according to the required coverage degree so as to prepare the single-layer tungsten disulfide single-crystal film on the sapphire substrate. The invention can realize the batch preparation of large-area and high-quality single-layer tungsten disulfide monocrystal film samples by using a low-pressure chemical vapor deposition method.

Inventors

  • ZHANG YANFENG
  • WANG JIALONG

Assignees

  • 北京大学

Dates

Publication Date
20260505
Application Date
20260122

Claims (8)

  1. 1. The method adopts a low-pressure chemical vapor deposition method, takes a sapphire substrate with a modification layer containing tungsten as a substrate, takes sulfur powder and tungsten trioxide powder as precursor sources, carries out the growth of single-layer single-orientation tungsten disulfide domain areas, and adjusts and controls the growth time of the single-layer single-orientation tungsten disulfide domain areas according to the required coverage degree so as to prepare the single-layer tungsten disulfide single-crystal film on the sapphire substrate.
  2. 2. The method for producing a single-layer tungsten disulfide single-crystal thin film according to claim 1, comprising the steps of: 1) Cleaning the (0001) plane of the sapphire substrate; 2) Under argon atmosphere, the sapphire substrate and tungsten trioxide powder placed under the sapphire substrate are kept at 900-1050 ℃ for 1-2 hours, so that tungsten trioxide is deposited on the surface of the sapphire substrate, and the sapphire substrate deposited with tungsten trioxide is obtained; 3) Continuously heating the sapphire substrate deposited with the tungsten trioxide to 1200-1300 ℃ under the atmosphere, and preserving the temperature for 1-3 hours to form a modification layer containing tungsten element on the surface of the sapphire substrate; 4) Under argon atmosphere, in a low-pressure state of 60-80 Pa, heating the sapphire substrate with the modification layer containing tungsten element, tungsten trioxide powder placed below the sapphire substrate and sulfur powder placed upstream the sapphire substrate in a partitioning manner, and growing a single-layer single-orientation tungsten disulfide domain; 5) And regulating the growth time of the single-layer single-orientation tungsten disulfide domain region to 1-15 minutes according to the coverage, and cooling to room temperature after the growth is finished to obtain the single-layer tungsten disulfide single-crystal film on the sapphire substrate.
  3. 3. The method for producing a single-layer tungsten disulfide single-crystal thin film according to claim 2, wherein in the step 1), the cleaning of the sapphire substrate is treated in such a manner that the (0001) plane of the sapphire substrate is sequentially subjected to ultrasonic cleaning in deionized water and absolute ethanol for 30 minutes each, followed by blow-drying with an air gun.
  4. 4. The method for preparing a single-layer tungsten disulfide single-crystal thin film according to claim 2, wherein in the step 2), tungsten trioxide is deposited on a sapphire substrate, wherein the cleaned sapphire substrate is placed in a high-temperature tube furnace, 50-100 mg of tungsten trioxide powder is placed below the sapphire substrate, argon gas of 200-500 sccm is introduced for 30 minutes for gas cleaning, then the flow rate of the argon gas is adjusted to 100-200 sccm, the tube furnace is heated to 900-1050 ℃ and then is kept for 1-2 hours, and the tube furnace is naturally cooled after the heat preservation is finished, wherein sccm is the volume flow rate unit and is standard cubic centimeter per minute.
  5. 5. The method for preparing a single-layer tungsten disulfide single-crystal thin film according to claim 2, wherein in step 3), a modification layer containing tungsten element is formed on the surface of the sapphire substrate, the sapphire substrate deposited with tungsten trioxide is placed in a high-temperature muffle furnace, and the temperature is raised to 1200-1300 ℃ under the atmosphere, and then the temperature is maintained for 1-3 hours, so as to form the modification layer containing tungsten element.
  6. 6. The method for producing a single-layer tungsten disulfide single-crystal thin film according to claim 2, wherein in step 4), the growth of the single-layer single-orientation tungsten disulfide domains is treated by placing a sapphire substrate having the modification layer containing tungsten element in a three-temperature-zone high-temperature tube furnace, placing 1 to 3 mg of tungsten trioxide powder below the sapphire substrate, placing 800 to 1200 mg of sulfur powder in the tube furnace upstream with respect to the sapphire substrate, pumping the tube furnace to a low-pressure state of 1 to 5 pascals by using a mechanical pump, and introducing 80 to 150 sccm argon as a growth carrier gas, and adjusting the gas pressure in the furnace to a low-pressure state of 60 to 80 pascals.
  7. 7. The method for producing a single-layer tungsten disulfide single-crystal thin film according to claim 2, wherein in step 4), the zonal temperature increase includes heating the region where the sulfur powder is located to 100-200 ℃, and heating the region where the sapphire substrate and the tungsten trioxide powder are located to 950-980 ℃.
  8. 8. The method for producing a single-layer tungsten disulfide single-crystal thin film according to claim 2, wherein in step 5), the time for growth is 1 to 15 minutes.

Description

Method for preparing single-layer tungsten disulfide single-crystal film Technical Field The invention belongs to the field of materials, and particularly relates to a method for preparing a single-layer tungsten disulfide single-crystal film. Background The two-dimensional transition metal chalcogenide (TMDCs) is taken as an important low-dimensional functional material in the rear graphene era, and has a unique layered crystal structure and an adjustable electronic energy band structure, so that the two-dimensional transition metal chalcogenide has wide application prospect in the fields of nano electronic devices, optoelectronic devices, flexible electronics and the like, and becomes a research hot spot in the fields of material science and condensed state physics. Compared with the traditional three-dimensional bulk phase material, the two-dimensional TMDCs has the advantages of ultrahigh specific surface area, excellent optical response characteristic, good mechanical flexibility and function customization realized through interlayer regulation, breaks through various limitations of the traditional semiconductor material in miniaturized and integrated application, and promotes the development of a low-dimensional photoelectric device to the high-performance and low-power consumption directions. It is worth noting that the unique physicochemical characteristics of the monolayer TMDCs can be fully exhibited only by relying on the high-quality monocrystalline film, and the polycrystalline film is easy to be attenuated due to the grain boundary defect, so that the preparation of the high-quality monolayer TMDCs monocrystalline film is a core premise for realizing the industrial application of the high-end optoelectronic device, and has important research value and practical necessity. Tungsten disulfide is used as a typical two-dimensional TMDCs material, has excellent physical and chemical properties, a crystal structure is of a hexagonal layered structure, atoms in layers are combined through strong covalent bonds, weak van der Waals force is used between layers, a single-layer tungsten disulfide has direct band gap semiconductor characteristics, the band gap is about 1.98 electron volts, compared with indirect band gaps of bulk tungsten disulfide, the single-layer tungsten disulfide has more excellent light absorption and light emission performance, and has good chemical stability, the structure and performance of the tungsten disulfide can be kept stable under a complex environment, and meanwhile, the tungsten disulfide also has excellent carrier mobility, good mechanical strength and flexibility, so that the tungsten disulfide becomes an ideal candidate material for constructing devices such as high-performance field effect transistors, photodetectors, light emitting diodes and the like. In summary, the realization of the preparation of single-layer tungsten disulfide single-crystal thin films is a key premise for the development of the field. Disclosure of Invention The invention aims to provide a method for preparing single-layer tungsten disulfide monocrystal films in batches with large area and high quality. In order to achieve the above purpose, the invention adopts the following technical scheme: The invention provides a method for preparing a single-layer tungsten disulfide single-crystal film, which adopts a low-pressure chemical vapor deposition method, takes a sapphire substrate with a modification layer containing tungsten elements as a substrate, takes sulfur powder and tungsten trioxide powder as precursor sources, carries out the growth of single-layer single-orientation tungsten disulfide domain areas, and adjusts and controls the growth time of the single-layer single-orientation tungsten disulfide domain areas according to the required coverage degree so as to prepare the single-layer tungsten disulfide single-crystal film on the sapphire substrate. The method for preparing the single-layer tungsten disulfide single-crystal film can comprise the following steps: 1) Cleaning the (0001) plane of the sapphire substrate; 2) Under argon atmosphere, the sapphire substrate and tungsten trioxide powder placed under the sapphire substrate are kept at 900-1050 ℃ for 1-2 hours, so that tungsten trioxide is deposited on the surface of the sapphire substrate, and the sapphire substrate deposited with tungsten trioxide is obtained; 3) Continuously heating the sapphire substrate deposited with the tungsten trioxide to 1200-1300 ℃ under the atmosphere, and preserving the temperature for 2-4 hours to form a modification layer containing tungsten element on the surface of the sapphire substrate; 4) Under argon atmosphere, in a low-pressure state of 60-80 Pa, heating the sapphire substrate with the modification layer containing tungsten element, tungsten trioxide powder placed below the sapphire substrate and sulfur powder placed upstream the sapphire substrate in a partitioning manner, and growing a si