Periodic hole array two-dimensional material and controllable preparation method and application thereof

Abstract

The application relates to the controllable etching field of two-dimensional materials, and particularly discloses a controllable preparation method of a two-dimensional material periodic hole array, which adopts laser to perform array etching on MX2 two-dimensional material to obtain a periodic point defect array MX2 two-dimensional material; M is a metal element, and X is at least one of S and Se; the point defect array MX2 two-dimensional material is annealed in a carrier gas, and different types of hole morphologies of the periodic hole array two-dimensional material are prepared by controlling the carrier gas type; the specific embodiments are as follows. The application can realize the controllable preparation of array holes, and the structure, morphology and interface of the prepared array holes are excellent.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of nanomaterials, and relates to a preparation method of a periodic pore array. TECHNICAL BACKGROUND

[0002] Since 2004, the discovery of graphene has triggered the rapid development of research on two-dimensional layered materials. Due to the many interesting properties provided by two-dimensional materials, they are expected to make a great contribution in the fields of electronics, optoelectronics, spintronics, catalysis, etc. [1-5] So far, the main difficulty in successfully integrating two-dimensional materials into practical applications is to realize large-scale growth of large-area and high-quality materials. Adopting chemical vapor deposition to obtain wafer-level two-dimensional nanosheets has become a general preparation strategy and is widely welcomed [6-12] . However, the growth mechanism of two-dimensional materials has not been fully revealed, and researchers urgently need to explore other reliable means to elucidate the growth process of two-dimensional materials.

[0003] Therefore, etching as a reverse growth process [13-14] is of great significance in studying the growth mechanism of materials. In the process of crystal growth, atoms are epitaxied at the front of the material, while etching removes atoms around the edges or defects of two-dimensional materials, which is different from the process of crystal growth. Since the edge structure of two-dimensional material crystals has a profound impact on their performance, studying the etching process, especially the etching parameters such as gas atmosphere, etching time, and temperature, will play an important role in the growth mechanism explanation. So far, the commonly used etching methods include wet etching

[15] and dry etching. In addition, laser etching [16-17] , thermal etching [18-19] , and atomic layer etching

[20] have also attracted people's attention, but it is still a great challenge for researchers to ensure that the quality of two-dimensional crystals remains unchanged and there is no residue at the etching interface after the etching process is completed.

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[0022]

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[0023] In view of the problem that the array hole of the existing two-dimensional material is difficult to be controllably prepared, the first object of the present application is to provide a controllable preparation method of a periodic hole array of a two-dimensional material, aiming to realize controllable high-quality construction of the array hole structure and morphology.

[0024] The second object of the present application is to provide a periodic hole array two-dimensional material prepared by the preparation method and an application thereof.

[0025] The existing etching hole array method for two-dimensional materials is relatively scarce, and the few etching methods have problems of poor controllability of hole structure and morphology, and non-ideal etching interface morphology, etc.

[0026] A controllable preparation method of a two-dimensional material periodic hole array, comprising the following steps:

[0027] Step (1):

[0028] The MX2 two-dimensional material is arrayed and etched by laser to obtain a periodic point defect array MX2 two-dimensional material; M is a metal element, and X is at least one of S and Se;

[0029] Step (2):

[0030] The point defect array MX2 two-dimensional material is annealed in a carrier gas, and different types of hole morphologies of the periodic hole array two-dimensional material are prepared by controlling the type of carrier gas; the specific embodiments include the following:

[0031] Method a: the carrier gas in the annealing stage is a hydrogen-containing atmosphere, and the annealing treatment obtains a MX2 two-dimensional material with a periodic positive triangular hole array;

[0032] Method b: the carrier gas in the annealing stage is a protective atmosphere, and the annealing treatment obtains a MX2 two-dimensional material with a periodic hexagonal hole array;

[0033] Method c: the carrier gas in the annealing stage is an X source-containing atmosphere, and the annealing treatment obtains a MX2 two-dimensional material with a periodic inverse triangular hole array.

[0034] The present application innovatively provides a laser-annealing combined etching scheme, and further based on the combined control of the atmosphere of annealing etching, different etching behaviors are induced to obtain array materials with different etching hole morphology structures, not only that, the method of the present application can effectively improve the etching hole uniformity, morphology and interface smoothness, and has excellent preparation effect.

[0035] In the present application, the technical scheme theoretically applies to any two-dimensional material, for example, the MX2 two-dimensional material can also be replaced by at least one of halides, oxyhalides, carbides or nitrides of transition metals.

[0036] In the present application, in the MX2 two-dimensional material, M is a metal element which can be any transition metal, preferably at least one of W and Mo.

[0037] In the present application, the MX2 two-dimensional material can be prepared based on existing methods, for example, the MX2 two-dimensional material is prepared on a substrate based on a PVD or CVD method. The substrate is, for example, a Si / SiO2 substrate, a sapphire substrate or a mica substrate; further preferably a Si / 285nm SiO2 substrate.

[0038] Preferably, the MX2 two-dimensional material is prepared by PVD deposition of MX2 raw material under a protective carrier gas;

[0039] Further preferably, the MX2 two-dimensional material is WS2, the PVD deposition temperature is 1150-1250℃, the PVD deposition time is 2-10min, and the protective carrier gas flow is 45-100sccm; more preferably, the PVD deposition temperature is 1195-1200℃, the PVD deposition time is 2-7min, and the protective carrier gas flow is 45-75sccm;

[0040] Further preferably, the MX2 two-dimensional material is WSe2, the PVD deposition temperature is 1120-1200℃, the PVD deposition time is 2-8min, and the protective carrier gas flow is 80-150sccm; more preferably, the PVD deposition temperature is 1120-1190℃, the PVD deposition time is 2-5min, and the protective carrier gas flow is 80-120sccm;

[0041] Further preferably, the MX2 two-dimensional material is MoS2, the PVD deposition temperature is 1180-1250℃, the PVD deposition time is 10-40min, and the protective carrier gas flow is 60-120sccm; more preferably, the PVD deposition temperature is 1180-1200℃, the PVD deposition time is 10-30min, and the protective carrier gas flow is 80-120sccm;

[0042] Preferably, the protective carrier gas is an inert gas;

[0043] Preferably, the PVD deposition process is carried out using a variable gas technique, that is, a reverse gas flow is used during the temperature rising PVD deposition temperature stage, and when the temperature reaches the PVD deposition temperature, the gas flow is changed to a forward gas flow. The reverse carrier gas flow refers to the direction of the substrate blowing towards the MX2 solid powder sample; the forward carrier gas flow refers to the direction of the MX2 solid powder sample blowing towards the substrate;

[0044] In the present application, the two-dimensional material can be subjected to dot pattern processing based on known laser equipment.

[0045] In step (1), the laser ablation is carried out using a fixed-point laser irradiation device;

[0046] Preferably, the device for the site-specific laser irradiation is a laser confocal microscopic Raman spectrometer.

[0047] Preferably, the MX2 two-dimensional material is irradiated by the focused laser radiation in a raster scanning mode to form a periodic array of point defects.

[0048] Preferably, the wavelength of the laser is 300-650 nm.

[0049] Preferably, the power of the laser is 10-60 mw.

[0050] Preferably, the laser scanning mode is a Raman point-by-point scanning mode and a Raman direct whole scanning mode, preferably the Raman point-by-point scanning mode; the Raman point-by-point scanning mode is a point-to-point point-by-point scanning mode and a line focusing scanning mode, preferably the point-to-point point-by-point scanning mode.

[0051] Preferably, the single-point irradiation time of the laser is 0.1-10 s, further preferably 4-6 s.

[0052] Preferably, the magnification of the objective lens is 5-100 times.

[0053] Preferably, the spacing of each point defect is 5-20 μm.

[0054] In the present application, the laser point arraying and annealing process are combined innovatively, and the etching morphology and interface are controlled by the carrier gas atmosphere. In step (2), the temperature of the annealing stage is 950-1100 ℃, further preferably 1000-1050 ℃; preferably, the annealing time is 30-60 s.

[0055] According to the type of the carrier gas, the technical solution can be divided into the following three main embodiments, for example:

[0056] In scheme a, the point defect array MX2 two-dimensional material prepared in step (1) is placed on a carrier with the surface facing upward, and is subjected to annealing treatment in a hydrogen-containing atmosphere to obtain a forward triangular hole array material. The forward triangle refers to that the three sides of the triangle are parallel to the three sides of the geometric triangle of the MX2 two-dimensional material.

[0057] Preferably, the hydrogen-containing atmosphere is a mixture of hydrogen gas and a protective atmosphere.

[0058] Preferably, in the hydrogen-containing atmosphere, the content of hydrogen is greater than or equal to 1 v%, preferably 1-3 v%.

[0059] Preferably, in scheme a, the protective atmosphere is an inert gas.

[0060] Preferably, in scheme a, the annealing temperature is 1000-1050 ℃.

[0061] Preferably, in scheme a, the annealing time is 35-45 s.

[0062] In scheme b, the point defect array MX2 two-dimensional material prepared in step (1) is placed on a carrier with the surface facing upwards, and annealing treatment is performed in a protective atmosphere;

[0063] Preferably, in scheme b, the protective atmosphere is an inert gas.

[0064] Preferably, in scheme b, the annealing temperature is 1000-1050°C.

[0065] Preferably, in scheme b, the annealing time is 35-45 s.

[0066] Preferably, in scheme c of step (2), the X source is placed in a carrier, and the point defect array MX2 two-dimensional material prepared in step (1) is erected above it in the direction of the X source, and annealing treatment is performed to obtain an array material of reverse triangular pores. The reverse triangle refers to three edges that are alternately and reversely parallel to the three edges of the triangular shape of the MX2 two-dimensional material, that is, the forward triangle is flipped 180° in the vertical direction;

[0067] Preferably, the point defect array MX2 two-dimensional material is inserted obliquely (MX2 two-dimensional material and carrier contact at one edge) into the carrier, or placed flat on the surface of the carrier, forming a microcavity reaction structure.

[0068] Preferably, the carrier is an alumina boat, a quartz boat or a porcelain boat.

[0069] Preferably, the carrier gas in the annealing stage also contains a protective gas.

[0070] Preferably, the ratio of the X source to the point defect array MX2 two-dimensional material is 2000 mg·cm -2 -6000 mg·cm -2 ; further preferably 2500-5500 mg·cm -2 , more preferably 2569 mg·cm -2 -5138 mg·cm -2 ; in the present application, at the preferred ratio, the morphology and interface of the reverse triangular pores are more controllable, and the preparation is more facilitated.

[0071] Preferably, the annealing treatment temperature is 1000-1050°C.

[0072] Preferably, the annealing time is 35-45 s.

[0073] The present application also provides a periodic pore array two-dimensional material prepared by the method.

[0074] The application also provides the application of the periodic pore array two-dimensional material prepared by the method, which is used for preparing a catalytic material, used as a template for epitaxial growth of other two-dimensional materials, and / or used for preparing optical, electrical and magnetic devices.

[0075] The application also provides materials and devices prepared from the periodic pore array two-dimensional material.

[0076] Advantages

[0077] The application innovatively provides a laser-annealing combined etching scheme, and further induces different etching behaviors based on the combined control of the atmosphere of annealing etching, so that an array material with different etching hole morphological structures is obtained.

[0078] The method of the application provides a new etching idea for researchers, and can explore the specific process of material growth. BRIEF DESCRIPTION OF DRAWINGS

[0079] Figure 1 Figure 1 is a confocal laser imaging single-layer WS2 point defect array of Example 1, (a) is an optical image of WS2 point defects formed after laser irradiation, (b) is an atomic force height image of an enlarged view of one of the point defects, and (c) is a STEM image of an enlarged view of one of the point defects. The scale of figure (a) is 5 μm, and the scale of figures (b, c) is 1 μm.

[0080] Figure 2 Figure 4 is a schematic diagram of a rapid high-temperature thermal etching process.

[0081] Figure 3 Figure 5 is a low-magnification optical image of a forward triangular etching hole array and a reverse triangular etching hole array of Example 1 and Example 3, (a) is a low-magnification optical image of WS2 with a forward triangular etching hole array, (b) is a low-magnification optical image of WS2 with a reverse triangular etching hole array, (c) is a low-magnification optical image of WSe2 with a forward triangular etching hole array, and (d) is a low-magnification optical image of WSe2 with a reverse triangular etching hole array. The scale of all figures is 20 μm.

[0082] Figure 4Figure 1 is an array of forward triangular etch pits on a monolayer of WS2of Example 1. (a) is an optical image of WS2with an array of forward triangular etch pits. (b) is a corresponding AFM image of WS2with an array of forward triangular etch pits. (c) is a scanning electron microscope image of WS2with an array of forward triangular etch pits. (d) is a Raman mapping of WS2with an array of forward triangular etch pits. The scale bar for (a, c) is 10 pm, and for (b, d) is 5 pm.

[0083] Figure 5 Figure 2 is an atomic resolution iDPC-STEM image of the boundary of a forward triangular etch pit of Example 1. (a) is a low magnification dark field image of a forward triangular etch pit. (b, c) are atomic resolution z-contrast iDPC-STEM images of two adjacent boundaries of a forward triangular etch pit. The scale bar for (a) is 1 pm, and for (b, c) is 1 nm.

[0084] Figure 6 Figure 3 is an array of hexagonal etch pits on a monolayer of WS2of Example 2. (a) is an optical image of WS2with an array of hexagonal etch pits. (b) is a corresponding AFM image of WS2with an array of hexagonal etch pits. (c) is a scanning electron microscope image of WS2with an array of hexagonal etch pits. (d) is a Raman mapping of WS2with an array of hexagonal etch pits. The scale bar for (a, c) is 10 pm, and for (b, d) is 5 pm.

[0085] Figure 7 Figure 4 is an atomic resolution iDPC-STEM image of the boundary of a hexagonal etch pit of Example 2. (a) is a low magnification dark field image of a hexagonal etch pit. (b, c) are atomic resolution z-contrast iDPC-STEM images of two adjacent boundaries of a hexagonal etch pit. The scale bar for (a) is 1 pm, and for (b, c) is 1 nm.

[0086] Figure 8 Figure 5 is an array of reverse triangular etch pits on a monolayer of WS2of Example 3. (a) is an optical image of WS2with an array of reverse triangular etch pits. (b) is a corresponding AFM image of WS2with an array of reverse triangular etch pits. (c) is a scanning electron microscope image of WS2with an array of reverse triangular etch pits. (d) is a Raman mapping of WS2with an array of reverse triangular etch pits. The scale bar for (a, c) is 10 pm, and for (b, d) is 5 pm.

[0087] Figure 9Atomic resolution iDPC-STEM images of the reverse triangular etched hole boundary of Example 3. (a) Low magnification dark field image of the reverse triangular etched hole. (b, c) Atomic resolution z-contrast iDPC-STEM images of two adjacent boundaries. The scale bar in (a) is 1 μm and in (b, c) is 1 nm.

[0088] Figure 10 Photoluminescence spectra of the forward triangular hole of monolayer WS2 of Example 1. (a) Optical image of the forward triangular hole. (b) Photoluminescence mapping of the forward triangular hole at 632 nm. (c) Photoluminescence spectra of the locations marked in (a). All scale bars in the figure are 5 μm.

[0089] Figure 11 Photoluminescence spectra of the reverse triangular hole of monolayer WS2 of Example 3. (a) Optical image of the reverse triangular hole. (b) Photoluminescence mapping of the reverse triangular hole at 632 nm. (c) Photoluminescence spectra of the locations marked in (a). All scale bars in the figure are 5 μm.

[0090] Figure 12 Etching of monolayer WS2 with different amounts of sulfur powder of Example 4. (a) Optical image of the etched hole array of monolayer WS2 with the ratio of sulfur powder to point defect array MX2 two-dimensional material of about 856 mg-cm -2 (b) Optical image of the etched hole array of monolayer WS2 with the ratio of sulfur powder to point defect array MX2 two-dimensional material of about 7707 mg-cm -2 (b) Optical image of the etched hole array of monolayer WS2 with the ratio of sulfur powder to point defect array MX2 two-dimensional material of about 7707 mg-cm

[0091] Figure 13 Reverse triangular etched hole array on monolayer WSe2 of Example 5. (a) Optical image of WSe2 with reverse triangular etched hole array. (b) Raman mapping of WSe2 with reverse triangular etched hole array. All scale bars in the figure are 10 μm.

[0092] Figure 14 Reverse triangular etched single hole on monolayer MoS2 of Example 6. (a) Optical image of MoS2 with reverse triangular etched single hole. (b) Raman mapping of MoS2 with reverse triangular etched single hole. All scale bars in the figure are 10 μm.

[0093] Figure 15Optical images of etched hole arrays of the single layer WS2 of Example 7 at different annealing temperatures (the etching time is 40 s). (a-c) are optical images of forward triangle etched hole arrays at different annealing temperatures. (d-f) are optical images of hexagon etched hole arrays at different annealing temperatures. (g-i) are optical images of reverse triangle etched hole arrays at different annealing temperatures. All the scales in the figures are 10 μm. DETAILED DESCRIPTION

[0094] The application is further illustrated by the following examples, but the application is not limited to the following content.

[0095] The method for controllable preparation of a periodic hole array of a two-dimensional material comprises the following steps:

[0096] Step (a): using material A powder as raw material, preheating to a deposition temperature under reverse gas flow, and then performing physical vapor deposition on the surface of a silicon / silicon dioxide substrate under forward gas flow to form a single-crystal nanosheet of material A;

[0097] Step (b): obtaining a material A nanosheet with an array of point defects by laser spot irradiation of the material A nanosheet; preferably, step (b) is performed using a laser confocal microscopic Raman spectrometer as a laser light source, i.e. an array of point defects is made on the material A nanosheet. Preferably, the array of point defects is prepared on the material A nanosheet by selecting conditions such as laser scanning mode, laser wavelength, laser power and laser irradiation time. Preferably, the wavelength of the laser is selected to be 488 nm; the power of the laser is selected to be 20 mw; the laser scanning mode is selected to be a Raman point-by-point scanning mode; the Raman point-by-point scanning mode is selected to be a point-to-point point-by-point scanning mode; the laser single-point irradiation time is selected to be 5 s; the magnification of the objective lens is selected to be 100 times; and the spacing of each point defect is selected to be 10 μm.

[0098] Step (c): placing the obtained material A nanosheet with periodic point defects in an alumina boat with the front face upward (or the front face downward), changing the gas composition in the annealing system, and annealing the material A nanosheet with the array of point defects into a nanosheet with three kinds of periodic hole arrays under the condition of high-temperature rapid annealing; the material A nanosheet placed in the alumina boat with the front face upward means that the silicon / silicon dioxide with the two-dimensional material sample is placed in the alumina boat, quartz boat or porcelain boat with the front face upward; the material A nanosheet placed in the alumina boat, quartz boat or porcelain boat with the front face downward means that the silicon / silicon dioxide with the two-dimensional material sample is inserted into the alumina boat, quartz boat or porcelain boat with the front face downward; preferably, the carrier is at least one of an alumina boat, a quartz boat or a porcelain boat, and preferably an alumina boat;

[0099] A reverse gas flow is introduced during the heating process of growing the material A nanosheet to stabilize the two-dimensional material that has been grown.

[0100] Further preferably, the atmosphere is an atmosphere of argon mixed with hydrogen or an atmosphere of pure argon, and the silicon / silicon dioxide with the two-dimensional material sample is placed in the alumina boat with the silicon / silicon dioxide face upwards;

[0101] Further preferably, the atmosphere is an atmosphere of argon mixed with hydrogen or an atmosphere of pure argon, and the silicon / silicon dioxide with the two-dimensional material sample is placed in the alumina boat with the silicon / silicon dioxide face upwards;

[0102] As a preference, the material A is selected to be WSe2.

[0103] As a preference, the atmosphere is an atmosphere of argon mixed with hydrogen or an atmosphere of pure argon, an atmosphere of argon mixed with selenium vapor;

[0104] Further preferably, the atmosphere is an atmosphere of argon mixed with hydrogen or an atmosphere of pure argon, and the silicon / silicon dioxide with the two-dimensional material sample is placed in the alumina boat with the silicon / silicon dioxide face upwards;

[0105] Further preferably, the atmosphere is an atmosphere of argon mixed with hydrogen or an atmosphere of pure argon, and the silicon / silicon dioxide with the two-dimensional material sample is placed in the alumina boat with the silicon / silicon dioxide face upwards;

[0106] As a preference, the material A is selected to be MoS2.

[0107] As a preference, the atmosphere is an atmosphere of argon mixed with hydrogen or an atmosphere of pure argon, an atmosphere of argon mixed with selenium vapor;

[0108] Further preferably, the atmosphere is an atmosphere of argon mixed with hydrogen or an atmosphere of pure argon, and the silicon / silicon dioxide with the two-dimensional material sample is placed in the alumina boat with the silicon / silicon dioxide face upwards;

[0109] Further preferably, the atmosphere is an atmosphere of argon mixed with hydrogen or an atmosphere of pure argon, and the silicon / silicon dioxide with the two-dimensional material sample is placed in the alumina boat with the silicon / silicon dioxide face upwards;

[0110] As a preference, the annealing temperature is selected to be 1000℃;

[0111] As a preference, the annealing time is selected to be 40s;

[0112] As a preference, the material A single-crystal nanosheet geometry is a triangular shape;

[0113] As a preference, the hydrogen flow rate is 3sccm;

[0114] As a preference, the selenium vapor is obtained by thermal evaporation of elemental selenium, and further preferably the mass of the elemental selenium is 1mg;

[0115] As a preference, the selenium vapor is obtained by thermal evaporation of elemental selenium, and further preferably the mass of the elemental selenium is 1mg;

[0116] The substrate is a Si / SiO2 substrate, a sapphire substrate or a mica substrate; further preferably a Si / 285nm SiO2 substrate.

[0117] The method of the application, wherein the device for implementing the nanosheet growth deposition of the material comprises a Tianjin Zhonghuan vacuum tube furnace, the heating device of the high-temperature constant-temperature zone of the tube furnace is located in the center of the furnace, and the powder solid of the two-dimensional material is loaded in an alumina boat or a quartz boat and placed in the high-temperature region in the middle of the quartz tube of the tube furnace; the environment for the growth of the two-dimensional material is a quartz tube with a length of 1 m and a tube diameter of 2 cm, and there is a variable-temperature deposition region at a position close to each end of the quartz tube through the non-insulation refractory cotton, and the variable-temperature region is free of heating devices; and the substrate is placed in the variable-temperature region at either end for convenient operation.

[0118] The ends of the quartz tube are respectively provided with flanges and rubber ring gaskets for sealing, two gas holes are respectively arranged on the two sides of the flange device, the two gas holes close to the substrate are marked as gas hole 1 and gas hole 2, and the two gas holes close to the raw material are marked as gas hole 3 and gas hole 4; the application considers that there is no essential difference between the gas hole 1 and the gas hole 2, and there is no essential difference between the gas hole 3 and the gas hole 4.

[0119] In the process of growing the nanosheet of the material A, in the application, in the stage before the powder solid sample in the center heating high-temperature zone is programmed to grow to the temperature, the gas hole 1 or 2 is the inlet of the carrier gas, and the gas hole 3 or 4 is the outlet of the carrier gas; after the powder solid sample in the center heating high-temperature zone is programmed to grow to the temperature, the gas hole 4 or 3 is the inlet of the carrier gas, and the gas hole 2 or 1 is the outlet of the carrier gas.

[0120] In the application, in step (a), in the stage from the start of the heating device of the tube furnace to the temperature of the high-temperature constant-temperature region reaching about 300 degrees Celsius, the gas hole 1 or 2 is the inlet of the carrier gas, and the gas hole 3 or 4 is the outlet of the carrier gas; a large argon flow is used to flush the pipeline to remove impurity gases and water in the tube, and the argon flow is adjusted to be small when the temperature reaches about 300 degrees Celsius; in the process of continuous blowing of the carrier gas, the powder solid of the two-dimensional material A is programmed to grow in the high-temperature constant-temperature region, and the nanosheet of the two-dimensional material A is prepared by depositing on the surface of the substrate in the variable-temperature region when the temperature reaches the growth temperature.

[0121] As preferred, the material A is WS2, the further preferred growth temperature is 1195-1200℃, the WS2 solid powder sample is 3g, the growth time is 2-7min, the large flow of the flushing pipeline carrier gas is 640sccm, and the growth condition carrier gas flow is 45-75sccm;

[0122] As the preferred material A, WSe2 is used, the growth temperature is preferably 1120-1190 DEG C, the solid powder sample of WSe2 is 3g, the growth time is 2-5min, the large flow of the flushing pipeline carrier gas is 640sccm, and the growth condition carrier gas flow is 80-120sccm;

[0123] As the preferred material A, MoS2 is used, the growth temperature is further preferably 1180-1200 DEG C, the solid powder sample of MoS2 is 3g, the growth time is 10-30min, the large flow of the flushing pipeline carrier gas is 640sccm, and the growth condition carrier gas flow is 80-120sccm;

[0124] The present application also includes a laser irradiation technology for implementing the preparation method, and the laser of the laser technology uses a laser confocal microscopic Raman spectrometer as a laser light source.

[0125] The present application also includes a rapid high-temperature annealing device for implementing the preparation method, and the annealing device is a single-temperature-zone tube furnace.

[0126] The present application is a kind of terminal atom control two-dimensional material on the preparation method of periodic hole array, comprising the following steps:

[0127] Step (1): the powder solid source of material A is loaded in an alumina boat, a quartz boat or a porcelain boat, and is placed in the middle high-temperature constant temperature area in the tube furnace quartz tube (2cm tube diameter).

[0128] The material A is WS2, the pipeline is cleaned by argon gas (for example, the flow of argon gas is 640sccm, and the time of input is 5min), argon gas is used as the carrier gas during the heating process, the growth temperature of WS2 is 1195 DEG C-1200 DEG C, the growth time is 2-7min, and the carrier gas flow is 45-75sccm.

[0129] The material A is WSe2; the pipeline is cleaned by argon gas in advance (the flow rate of argon gas is, for example, 640 sccm, and the time of being introduced is, for example, 5 min), argon gas is used as a carrier gas in the heating process, the growth temperature of WSe2 is 1120-1190℃, the growth time is 2-5 min, and the flow rate of the carrier gas is 80-120 sccm; after the growth is completed, the monolayer single-crystal WSe2 nanosheet is deposited on the surface of the substrate;

[0130] The material A is MoS2; the pipeline is cleaned by argon gas in advance (the flow rate of argon gas is, for example, 640 sccm, and the time of being introduced is, for example, 5 min), argon gas is used as a carrier gas in the heating process, the growth temperature of MoS2 is 1180-1200℃, the growth time is 10-30 min, and the flow rate of the carrier gas is 80-120 sccm; after the growth is completed, the monolayer single-crystal MoS2 nanosheet is deposited on the surface of the substrate;

[0131] Step (2): the material A nanosheet is placed on the object table under the lens of the Raman microscope, and is scanned in a point-to-point scanning mode to prepare a point defect array on the material A nanosheet.

[0132] Step (3): the material A nanosheet with the point defect array is placed in a rapid high-temperature annealing device to be annealed, so as to obtain the material A nanosheet with a hole structure of different shapes. The step includes the following steps:

[0133] Step (a): the tubular furnace is programmed to be heated to 1000℃, and the silicon / silicon dioxide with the two-dimensional material sample is placed in the alumina boat; the end of the quartz hook is fixed with a magnet, the alumina boat is hooked by the quartz hook, and the alumina boat can be moved forward and backward at will under the attraction of the inner and outer magnets, so as to control the position of the material sample in the quartz tube.

[0134] Step (b): the silicon / silicon dioxide with the two-dimensional material sample is placed in the alumina boat with the front face upward. The pipeline is cleaned by argon gas for 20 min, then the outer magnet is moved to drive the quartz hook to push the alumina boat and the two-dimensional material sample into the vicinity of the central heating zone. The carrier gas is changed to 200 sccm of argon gas and 3 sccm of hydrogen gas. After being annealed for a period of time, the alumina boat with the two-dimensional material sample is pulled out by the outer magnet, and the furnace is naturally cooled.

[0135] Step (c): the silicon / silicon dioxide with the two-dimensional material sample is placed in the alumina boat with the front face upward. The pipeline is cleaned by argon gas for 20 min, then the outer magnet is moved to drive the quartz hook to push the alumina boat and the two-dimensional material sample into the vicinity of the central heating zone. The carrier gas is changed to 200 sccm of argon gas. After being annealed for a period of time, the alumina boat with the two-dimensional material sample is pulled out by the outer magnet, and the furnace is naturally cooled.

[0136] Step (d): Put sulfur powder or selenium powder at the front end of the alumina boat, place the single-layer two-dimensional material sample with periodic defects (facing down) above the sulfur powder or selenium powder in the alumina boat, and place the sulfur solid or selenium solid evaporation to form a microcavity reaction chamber. First, purge the pipeline with argon for 20 min, then move the external magnet to drive the quartz hook to push the alumina boat and the two-dimensional material sample into the vicinity of the central heating zone. Change the carrier gas to 200 sccm of argon. Anneal for a period of time, move the external magnet to pull out the alumina boat containing the two-dimensional material sample, and naturally cool the furnace.

[0137] Example 1 - Preparation of WS2 controllable array hole mode a

[0138] (1) Preparation of single-layer tungsten sulfide

[0139] Weigh 3 g of WS2 solid powder sample and load it into an alumina boat, and place the alumina boat in the central high-temperature heating area of the quartz tube of the tube furnace (1 m long, 2 cm in diameter). Place an alumina boat loaded with a Si / 285 nm SiO2 substrate in the temperature zone of the tube furnace, and the substrate is used to deposit single-layer WS2 nanosheets.

[0140] First, purge the pipeline with argon (for example, the flow rate of argon is 640 sccm, and the purging time is 5 min). Use argon as the carrier gas during heating, and the carrier gas flow rate is 75 sccm. Before the growth temperature, the gas flow direction is always from the substrate to the WS2 solid powder raw material. When the program temperature is raised to the growth temperature of WS2, which is 1200°C (PVD deposition temperature), the gas flow direction is set to from the WS2 solid powder raw material to the substrate. The growth time is 7 min, and then the heating tube furnace is stopped for 3 h before cooling to room temperature to obtain single-layer WS2 nanosheets.

[0141] (2) Preparation of point defect array on WS2 nanosheet

[0142] Place the single-layer single-crystal WS2 nanosheet obtained in (1) on the object table under the lens of the Raman microscope, and select a focused laser (488 nm, 20 mw) to perform point-to-point scanning in point-to-point scanning mode. The single-point radiation of the single-layer WS2 is about 5 s, and a periodic point defect array of the single-layer WS2 is prepared (in this case, the distance between adjacent point defects is 10 μm).

[0143] (3) Annealing in a rapid high-temperature annealing device

[0144] Program the tube furnace to 1000°C, and after reaching 1000°C, place the silicon / silicon dioxide containing the single-layer WS2 sample with a point defect array in the alumina boat, with the silicon / silicon dioxide facing upwards. The end of the quartz hook is fixed with a magnet, the quartz hook hooks the tail hole of the alumina boat, and the alumina boat is placed away from the central heating zone.

[0145] The pipeline was purged with argon for 20 min at a flow rate of 640 seem, and then the external magnet was moved to push the alumina boat and the two-dimensional material sample into the vicinity of the central heating zone. The carrier gas was changed to 200 seem of argon and 3 seem of hydrogen. After annealing at 1000 °C for 40 s, the external magnet was moved to pull out the alumina boat containing the two-dimensional material sample, and the furnace was naturally cooled to obtain WS2nanosheets with the laser-etched hole defect region changed into a forward triangular hole array.

[0146] Figures 4-5 To prepare optical images, atomic force images, Raman mapping and iDPC-STEM images of the forward triangular hole array sample, it was proved that the obtained sample had a clear periodic hole array and excellent performance.

[0147] Example 2 - WS2 controllable array hole method b preparation

[0148] Compared with Example 1, the only difference is that in step (3), the gas introduced is 200 seem of pure argon (i.e., the carrier gas of 200 seem of argon and 3 seem of hydrogen is changed to 200 seem of pure argon).

[0149] Figures 6-7 To prepare optical images, atomic force images, Raman mapping and iDPC-STEM images of the hexagonal hole array sample, it was proved that the obtained sample had a clear periodic hole array and excellent performance.

[0150] Example 3 - WS2 controllable array hole method c preparation

[0151] Compared with Example 1, the only difference is that in step (3), the sulfur powder (2569 mg cm -2 ) is placed at the front end of the alumina boat, and the silicon / silicon dioxide with the two-dimensional material sample is placed obliquely in the alumina boat with the front face downward (facing the sulfur powder) (i.e., the silicon / silicon dioxide containing the point defect array monolayer WS2 sample is placed with the front face upward is changed to be placed with the front face downward and obliquely in the alumina boat), and the sulfur solid is evaporated to form a microcavity reaction chamber. The carrier gas during the annealing stage is changed to 200 seem of argon. Other operations and parameters are the same as those in Example 1.

[0152] Figures 8-9 To prepare optical images, atomic force images, Raman mapping and iDPC-STEM images of the reverse triangular hole array sample, it was proved that the obtained sample had a clear periodic hole array and excellent performance.

[0153] Example 4 - WS2 controllable array hole method c preparation

[0154] Compared with Example 3, the only difference is that the amount of sulfur powder is controlled, and the experimental groups are as follows: Group A: the ratio of sulfur powder to point defect array MX2 two-dimensional material is about 856 mg·cm-2; Group B: the ratio of sulfur powder to point defect array MX2 two-dimensional material is about 7707 mg·cm-2. Other operations and parameters are the same as those in Example 3. -2 -2

[0155] Figure 12 The optical images of etched array holes of monolayer WS2 under different amounts of sulfur powder are shown, which prove that when the amount of sulfur powder is too small, the shape of the array hole obtained is a blunt truncated triangular hole, and when the amount of sulfur powder is too large, the point defects generated by laser irradiation will be blocked, resulting in ineffective etching, so the amount of sulfur powder is preferably 2569 mg·cm-2 to 5138 mg·cm-2 relative to the point defect array MX2 two-dimensional material. -2 -2

[0156] Example 5 - Preparation of WSe2 Controllable Array Hole Method c

[0157] Compared with Example 3, the only difference is that the two-dimensional material is WSe2 two-dimensional material, and the sulfur powder is replaced with selenium powder, and the difference is in the following steps:

[0158] In step (1), the WSe2 growth temperature is 1180°C, the WSe2 solid powder sample is 3 g, the growth time is 3 min, and the carrier gas flow is 120 sccm; other conditions remain unchanged.

[0159] In step (3), the sulfur powder is replaced with selenium powder (5100 mg·cm-2 relative to the point defect array MX2 two-dimensional material), and other conditions remain unchanged. -2

[0160] Figure 13 The optical picture and Raman mapping of the prepared reverse triangular hole array sample prove that the obtained sample has a clear periodic hole array and excellent performance.

[0161] Example 6 - Preparation of MoS2 Controllable Array Hole Method c

[0162] Compared with Example 1, the only difference is that the raw material solid powder is replaced with MoS2.

[0163] In step (1), the MoS2 growth temperature is 1200°C, the MoS2 solid powder sample is 3 g, the growth time is 30 min, and the carrier gas flow is 80 sccm.

[0164] Figure 14 ​​​​​To prepare the optical picture and Raman mapping of the inverse triangular single-hole sample, it is proved that the sample has a clear periodic hole array and excellent performance.

[0165] Example 7 - Array hole preparation at different annealing temperatures

[0166] Compared with Example 1, the only difference is that the annealing temperature is changed to 950℃, 1050℃ and 1100℃ respectively. Other operations are the same as Example 1. The optical pictures are shown in Figs. a, b and c of Figure 15 respectively;

[0167] Compared with Example 2, the only difference is that the annealing temperature is changed to 950℃, 1050℃ and 1100℃ respectively. Other operations are the same as Example 1. The optical pictures are shown in Figs. d, e and f of Figure 15 respectively;

[0168] Compared with Example 3, the only difference is that the annealing temperature is changed to 950℃, 1050℃ and 1100℃ respectively. Other operations are the same as Example 1. The optical pictures are shown in Figs. g, h and i of Figure 15 respectively;

[0169] It can be seen from Figure 15 that under the combined process of laser and annealing, further controlling the annealing temperature to 1000-1050℃ can obtain better morphology coordination control effect, for example, improving the interface of the array hole, and can obtain 100% controllable effect.

Claims

1. A method for controllably preparing a two-dimensional material periodic hole array, characterized in that the steps include... include: Step (1): A laser is used to perform array etching on MX2 two-dimensional material to obtain a periodic point defect array MX2 two-dimensional material; where M is a metallic element and X is at least one of S and Se; Step (2): Two-dimensional point defect array MX2 material is annealed in a carrier gas, and periodic hole array two-dimensional materials with different pore morphologies are obtained by controlling the type of carrier gas; specifically, the following implementation methods are included: Method a: The carrier gas during the annealing stage is a hydrogen-containing atmosphere, and the annealing process yields an MX2 two-dimensional material with a periodic positive triangular hole array; Method b: During the annealing stage, the carrier gas is a protective atmosphere, and the annealing process yields an MX2 two-dimensional material with a periodic hexagonal pore array; Method c: The carrier gas in the annealing stage is an atmosphere containing an X source, and the annealing process yields an MX2 two-dimensional material with a periodic inverse triangular hole array.

2. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 1, characterized in that, M is a metallic element that is at least one of W and Mo.

3. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 1, characterized in that, The MX2 two-dimensional material is replaced by at least one of the transition metal halides, halide oxides, carbides, or nitrides.

4. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 2, characterized in that, The MX2 two-dimensional material was prepared using PVD or CVD methods.

5. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 4, characterized in that, The MX2 two-dimensional material is prepared by PVD deposition of MX2 raw material under a protective carrier gas.

6. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 5, characterized in that, The MX2 two-dimensional material is WS2, with a PVD deposition temperature of 1150-1250℃, a PVD deposition time of 2-10 min, and a protective carrier gas flow rate of 45-100 sccm; the protective carrier gas is an inert gas.

7. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 6, characterized in that, The MX2 two-dimensional material is WS2, the PVD deposition temperature is 1195-1200℃, the PVD deposition time is 2-7min, and the protective carrier gas flow rate is 45-75sccm.

8. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 5, characterized in that, The MX2 two-dimensional material is WSe2, the PVD deposition temperature is 1120-1200℃, the PVD deposition time is 2-8 min, and the flow rate of the protective carrier gas is 80-150 sccm; the protective carrier gas is an inert gas.

9. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 8, characterized in that, The MX2 two-dimensional material is WSe2, the PVD deposition temperature is 1120-1190℃, the PVD deposition time is 2-5 min, and the flow rate of the protective carrier gas is 80-120 sccm.

10. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 5, characterized in that, The MX2 two-dimensional material is MoS2, the PVD deposition temperature is 1180-1250℃, the PVD deposition time is 10-40 min, and the protective carrier gas flow rate is 60-120 sccm; the protective carrier gas is an inert gas.

11. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 10, characterized in that, The MX2 two-dimensional material is MoS2, the PVD deposition temperature is 1180-1200℃, the PVD deposition time is 10-30min, and the protective carrier gas flow rate is 80-120sccm.

12. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 5, characterized in that, The PVD deposition process employs a variable gas flow technique, which involves using a reverse airflow during the PVD deposition temperature rise stage and switching to a forward airflow once the PVD deposition temperature is reached.

13. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 1, characterized in that, In step (1), the array etching is performed using a device with fixed-point laser irradiation.

14. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 13, characterized in that, The device for point-to-point laser irradiation is a laser confocal micro Raman spectrometer.

15. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 13, characterized in that, A periodic array of point defects is formed by using a grating scanning focused laser to irradiate the MX2 two-dimensional material.

16. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 1, characterized in that, The wavelength of laser light is 300~650nm; The laser power is 10-60mw.

17. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 1, characterized in that, The laser scanning modes are Raman point-by-point scanning mode and Raman direct overall scanning mode; the Raman point-by-point scanning mode includes point-to-point point-by-point scanning mode and line focusing scanning mode.

18. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 17, characterized in that, The single-point laser radiation time is 0.1-10 seconds; Objective lens magnification 5-100x; The spacing between each point defect is 5-20µm.

19. The controllable fabrication method for a two-dimensional material periodic hole array as described in any one of claims 1 to 18, characterized in that, In step (2), the annealing temperature is 950-1100℃.

20. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 19, characterized in that, The annealing time is 30-60 seconds.

21. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 1, characterized in that, In step (2) in method a, the point defect array MX2 two-dimensional material obtained in step (1) is placed on the carrier with its surface facing upward and annealed in a hydrogen-containing atmosphere.

22. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 21, characterized in that, In step (2) method a, the hydrogen-containing atmosphere is a mixture of hydrogen and protective atmosphere; In the hydrogen-containing atmosphere, the hydrogen content is greater than or equal to 1% (v%). The protective atmosphere is an inert gas; The annealing temperature is 1000~1050℃; The annealing time is 35~45 seconds.

23. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 1, characterized in that, In step (2) in method b, the point defect array MX2 two-dimensional material obtained in step (1) is placed on the carrier with its surface facing upward, and annealed in a protective atmosphere; The protective atmosphere is an inert gas; The annealing temperature is 1000~1050℃; The annealing time is 35~45 seconds.

24. The controllable fabrication method for a two-dimensional material periodic hole array as described in claim 1, characterized in that, In step (2) in method c, the X source is placed in the carrier, and the point defect array MX2 two-dimensional material obtained in step (1) is placed on top of it with the X source in the direction of X source and then annealed. The point defect array MX2 two-dimensional material is obliquely inserted into the carrier or placed flat on the carrier surface to form a microcavity reaction structure; The carrier is an alumina boat, a quartz boat, or a ceramic boat; The carrier gas during the annealing stage also includes a protective gas; The ratio of the X source to the point defect array MX2 two-dimensional material is 2000 mg·cm⁻¹. -2 ~ 6000mg·cm -2 ; The annealing temperature is 1000~1050℃; The annealing time is 35~45 seconds.

25. A two-dimensional material with a periodic hole array prepared by the method of any one of claims 1 to 24.

26. An application of a two-dimensional material with a periodic aperture array prepared by the method according to any one of claims 1 to 24, characterized in that, It can be used to prepare catalytic materials, as a template for epitaxial growth of other two-dimensional materials, and / or for the preparation of optical, electronic, and magnetic devices.

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