A method of patterning thinned two-dimensional tellurene

Abstract

The application discloses a method for patterning and thinning two-dimensional tellurene, comprising the following steps: (1) transferring the prepared two-dimensional tellurene to a target substrate; (2) spin-coating electron beam resist on the surface of the two-dimensional tellurene in the target substrate, and then performing patterning on the electron beam resist by using an electron beam exposure method after baking; (3) placing the obtained two-dimensional tellurene with patterned electron beam resist in an oxidant solution for soaking, and performing selective etching and thinning on the exposed two-dimensional tellurene in the patterned area; (4) removing the electron beam resist on the surface of the two-dimensional tellurene by using an organic solvent, then washing with deionized water, and finally drying the washed two-dimensional tellurene at a certain temperature, so that the patterned and thinned two-dimensional tellurene is obtained. The thinning method is simple, green and economical, is suitable for the patterning and thinning of a large-area two-dimensional tellurium film, and avoids the material surface damage problem caused by high-energy particle bombardment in a traditional patterning and thinning method.

Description

Technical Field

[0001] This invention belongs to the technical field of two-dimensional nanomaterial preparation, specifically relating to a method for patterning and thinning two-dimensional tellurene. Background Technology

[0002] Two-dimensional tellurene, as a p-type single-element semiconductor, exhibits excellent room-temperature carrier mobility (>1000 cm⁻¹). 2 V -1 s -1 Two-dimensional tellurene (2D tellurene) exhibits great application potential in novel infrared photoelectric detection fields due to its high light absorption coefficient, continuously tunable bandgap (approximately 0.32-1.1 eV), good environmental stability, and significant in-plane anisotropy. Currently, the main methods for preparing 2D tellurene single crystals include chemical vapor deposition (CVD), physical vapor transport (PVT), hydrothermal synthesis, and molecular beam epitaxy (MBE). Among these, the hydrothermal method is the mainstream method for preparing 2D tellurene due to its simplicity, good controllability, and ease of large-area synthesis. However, tellurene synthesized using this method is generally quite thick and difficult to adjust by changing growth parameters. In photoelectric detection applications, a large material thickness can improve light absorption efficiency, but it also leads to increased dark current and weakened gate voltage tunability, thus reducing the device's detectivity. Patterning and thinning 2D tellurene with a certain thickness to achieve a balance between light absorption and dark current is an important means to improve the performance of tellurium-based photoelectric detection devices.

[0003] Traditional methods for patterning and thinning two-dimensional materials include plasma etching, focused ion beam etching, and laser ablation, which primarily utilize high-energy particle bombardment to physically thin the material. However, these patterning methods typically require expensive equipment such as plasma etching machines and focused ion beam systems, and must be performed in a high-vacuum environment, resulting in complex operations and low efficiency. Furthermore, the size of the thinned sample is limited by the working area of ​​the equipment. More importantly, high-energy particle bombardment can cause surface damage to the material, thereby affecting its electrical properties. Exploring new two-dimensional tellurene patterning and thinning techniques has become a crucial problem urgently needing to be solved in the current field of tellurium nanomaterials research. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for patterned thinning of two-dimensional tellurene. This thinning method uses an inorganic oxidant solution, is simple to operate, environmentally friendly and economical, and avoids the material surface damage problems caused by traditional methods such as plasma etching and focused ion beam etching.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for patterning and thinning two-dimensional tellurene, the method comprising the following steps:

[0007] (1) Transfer the pre-prepared two-dimensional tellurene to the target substrate;

[0008] (2) Spin-coat electron beam photoresist on the surface of the two-dimensional tellurene in the target substrate in step (1), bake after spin coating, and then use electron beam exposure method to pattern the electron beam photoresist on the surface of the two-dimensional tellurene.

[0009] (3) The two-dimensional tellurene with patterned electron beam photoresist obtained in step (2) is immersed in an oxidant solution for a certain period of time to selectively thin the two-dimensional tellurene exposed in the patterned area.

[0010] (4) First, remove the electron beam photoresist on the surface of the two-dimensional tellurene after step (3) with an organic solvent, then rinse with deionized water, and finally dry the cleaned two-dimensional tellurene at a certain temperature to obtain the patterned and thinned two-dimensional tellurene.

[0011] Furthermore, the two-dimensional tellurene in step (1) is prepared by hydrothermal method or thermal evaporation method.

[0012] Furthermore, the specific process of the hydrothermal method is as follows: First, weigh 0.5-3.0g of polyvinylpyrrolidone and 0.05-0.5g of sodium tellurite, dissolve them in 15-20ml of deionized water, and stir magnetically until the solution is clear; then, add 1-4ml of ammonia and 0.5-2.0ml of hydrazine hydrate to the clear solution in sequence, and continue to stir magnetically for 1min; finally, transfer the above solution to a 50ml hydrothermal reactor, and grow it in a constant temperature drying oven at 170℃-190℃ for 4-24h. After the reaction is completed, the product is centrifuged and washed multiple times to obtain the two-dimensional tellurene.

[0013] Furthermore, the specific process of the thermal evaporation method is as follows: First, the substrate is surface-treated using plasma; then, gold colloidal particles are spin-coated onto the substrate surface at a rotation speed of 500-5000 rpm, and the substrate with spin-coated gold particles is transferred into the evaporation chamber; finally, the evaporation chamber is evacuated to a vacuum level of 5 × 10⁻⁶. -4 Below Pa, thermal evaporation begins, using tellurium metal particles (purity > 99.999%) as the evaporation source for deposition. After deposition, the sample is removed to obtain the two-dimensional tellurene film.

[0014] Furthermore, the plasma power is 10-100W, the plasma treatment time is 0.5-5min; the diameter of the spin-coated gold colloidal particles is 10-100nm; the thermal evaporation deposition rate is 10-400nm / min, the deposition time is 5-120s, and the substrate rotation speed during the deposition process is 5-20rpm.

[0015] Furthermore, in step (1), the target substrate is any one of an insulating silicon substrate, a polyethylene terephthalate substrate, a polyimide substrate, a sapphire substrate, and a common glass substrate.

[0016] Furthermore, in step (2), the electron beam photoresist is polymethyl methacrylate with a molecular weight of 950K; the baking conditions are: baking at a temperature of 100℃-180℃ for 1-5 minutes.

[0017] Furthermore, in step (3), the oxidant is any one of nitrous acid, hydrogen peroxide, or potassium permanganate.

[0018] Furthermore, the soaking time in step (3) is 0.5-60 min.

[0019] Furthermore, the method for removing the electron beam photoresist from the surface of the two-dimensional tellurene in step (4) is as follows: the two-dimensional tellurene treated in step (3) is immersed in acetone, an organic solvent at a temperature of 60-100℃, for 0.5-2 hours.

[0020] Compared with the prior art, the positive and beneficial effects of this invention are as follows:

[0021] (1) This invention first spin-coates electron beam photoresist onto the surface of two-dimensional tellurene, then patterns the electron beam photoresist on the surface of the two-dimensional tellurene using electron beam exposure technology. Next, the patterned two-dimensional tellurene is immersed in an inorganic oxidant solution, and selectively and locally thins the two-dimensional tellurene through an oxidation-etching process. The pattern of the thinned region of the two-dimensional tellurene can be arbitrarily set as needed, and the thinning thickness can be precisely controlled by changing the oxidant concentration and immersion time.

[0022] (2) The present invention uses a combination of electron beam exposure process and inorganic solution to pattern thinning of two-dimensional tellurene, which avoids the material surface damage caused by high-energy particle bombardment in traditional plasma etching, focused ion beam etching and other methods. It provides a new idea for pattern thinning of two-dimensional tellurene and is conducive to promoting the application of two-dimensional tellurene in the field of new electronic and optoelectronic devices.

[0023] (3) The method for patterning and thinning two-dimensional tellurene provided by the present invention uses an aqueous solution of inorganic oxidant, which is green and economical, simple and convenient to operate, and suitable for patterning and thinning of large-area two-dimensional tellurene films. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the process of patterned thinning of two-dimensional tellurene in Embodiment 1 of the present invention;

[0025] Figure 2The images shown are optical microscope images (top left) of two-dimensional tellurene after patterning electron beam photoresist, atomic force microscope images (bottom left) of two-dimensional tellurene after patterning and thinning, and thickness measurement results (right) obtained in Embodiment 1 of the present invention.

[0026] Figure 3 The images shown are optical and atomic force microscope images (left) and Raman characterization spectrum (right) of the patterned and thinned two-dimensional tellurene obtained in Embodiment 2 of the present invention.

[0027] Figure 4 These are optical microscope images (left) of two-dimensional tellurene after patterning electron beam photoresist and (right) of two-dimensional tellurene after patterning and thinning, obtained in Embodiment 3 of the present invention.

[0028] in, Figure 1 The names of the substances represented by the superscript numbers are as follows:

[0029] 1. Silicon; 2. Silicon dioxide; 3. Two-dimensional tellurene; 4. Electron beam photoresist. Detailed Implementation

[0030] The technical solution of the present invention will be described in detail below with reference to examples. Obviously, the described examples are only a small part of the present invention, and not all examples. Based on the examples in the present invention, all other examples obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] A method for patterned thinning of two-dimensional tellurene, the flowchart of which is shown below. Figure 1 As shown, the specific steps are as follows:

[0033] (1) The two-dimensional tellurene single crystal prepared by hydrothermal method is transferred onto an insulating silicon (SiO2 / Si) substrate; wherein, the specific process of preparing two-dimensional tellurene by hydrothermal method is as follows: First, 0.11g of sodium tellurite and 0.6g of polyvinylpyrrolidone are weighed and dissolved in 16ml of deionized water, and magnetically stirred for 10min until the solution is clear; then, 2ml of ammonia water and 1ml of hydrazine hydrate are added to the above clear solution in sequence, and magnetic stirring is continued for 1min; finally, the above solution is transferred to a hydrothermal reactor with a capacity of 50ml and grown in an oven at 180℃ for 4.5h;

[0034] (2) In step (1), polymethyl methacrylate (950K) electron beam photoresist was spin-coated on the surface of the insulating silicon substrate on which two-dimensional tellurene was transferred at a speed of 3000 rpm for 50 s, and then the spin-coated insulating silicon substrate was placed on a hot plate at 160℃ and baked for 1 min.

[0035] (3) Using electron beam lithography, a "TE" patterned photoresist pattern was prepared on the two-dimensional tellurene surface baked in step (2). After development and fixing, it was dried with nitrogen gas. The optical microscope image is shown below. Figure 2 As shown in the top left image;

[0036] (4) The patterned substrate from step (3) is immersed in nitrous acid solution for 40 minutes, then rinsed with deionized water and dried with nitrogen gas; wherein, the preparation process of the nitrous acid solution is as follows: weigh 25 mg of sodium nitrite and mix it with 40 ml of hydrochloric acid solution with a concentration of 10 mmol / L.

[0037] (5) The substrate soaked in nitrous acid solution in step (4) is immersed in acetone solution at 85°C for 1 hour. After removal, it is cleaned with deionized water to obtain patterned and thinned two-dimensional tellurene. Its atomic force microscopy image and thickness measurement results are as follows: Figure 2 As shown in the lower left and right images.

[0038] Example 2

[0039] A method for patterning and thinning two-dimensional tellurene, which specifically includes the following steps:

[0040] (1) The two-dimensional tellurene single crystal prepared by hydrothermal method was transferred onto a polyethylene terephthalate substrate; wherein, the specific process of preparing two-dimensional tellurene by hydrothermal method is as follows: First, 0.05g of sodium tellurite and 1.5g of polyvinylpyrrolidone were weighed and dissolved in 16ml of deionized water, and the solution was magnetically stirred for 15min until the solution was clear and transparent; then, 1.6ml of ammonia water and 0.8ml of hydrazine hydrate were added to the above clear solution in sequence, and the solution was magnetically stirred for 1min; finally, the above solution was transferred to a hydrothermal reactor with a capacity of 50ml and grown in a constant temperature drying oven at 180℃ for 5h;

[0041] (2) In step (1), the surface of the polyethylene terephthalate substrate on which two-dimensional tellurene has been transferred is spin-coated with polymethyl methacrylate (950K) electron beam photoresist at a speed of 3000 rpm for 50 s, and then the spin-coated polyethylene terephthalate substrate is placed on a hot plate at 100℃ and baked for 2 min.

[0042] (3) A "strip" patterned photoresist pattern was prepared on the two-dimensional tellurene surface baked in step (2) using electron beam lithography. The "strip" was 3.5 μm wide. After development and fixing, it was dried with nitrogen gas. Its optical microscope image is shown below. Figure 3 As shown in the top left image;

[0043] (4) The patterned substrate in step (3) is immersed in hydrogen peroxide solution for 2 minutes, then rinsed with deionized water and dried with nitrogen gas; wherein, the preparation process of the hydrogen peroxide solution is as follows: 1 ml of 30% hydrogen peroxide is added to 1000 ml of deionized water and magnetically stirred for 1 minute to obtain the hydrogen peroxide solution.

[0044] (5) The substrate soaked in hydrogen peroxide solution in step (4) is immersed in acetone solution at 80°C for 0.5 h, then removed and cleaned with deionized water to obtain patterned and thinned two-dimensional tellurene; its atomic force microscopy image and Raman characterization results are as follows: Figure 3 The images are shown in the lower left and right sections.

[0045] Example 3

[0046] A method for patterning and thinning two-dimensional tellurene, which specifically includes the following steps:

[0047] (1) A large-area two-dimensional tellurene film was deposited on a sapphire substrate using a thermal evaporation method. The specific process of preparing the two-dimensional tellurene film by thermal evaporation is as follows: First, the surface of the sapphire substrate was treated with oxygen plasma to enhance its hydrophilicity; then, gold colloidal particles with a diameter of 10 nm were spin-coated on the surface of the sapphire substrate at a rotation speed of 2000 rpm. After spin-coating, the sapphire substrate was transferred to the evaporation chamber; finally, the vacuum of the evaporation chamber was evacuated to 5 × 10⁻⁶. -4 Below Pa, thermal evaporation begins, using high-purity tellurium metal particles (purity > 99.999%) as the evaporation source to deposit a two-dimensional tellurium film. The deposition rate is 300 nm / min, the deposition time is 15 s, and the substrate rotation speed is 10 rpm during the deposition process. After the deposition is completed, the sample is removed to obtain the two-dimensional tellurene film.

[0048] (2) In step (1), the surface of the sapphire substrate on which two-dimensional tellurene has been deposited is spin-coated with polymethyl methacrylate (950K) electron beam photoresist at a speed of 2000 rpm for 55s, and then the spin-coated polyethylene terephthalate substrate is placed on a hot plate at 180℃ and baked for 1min.

[0049] (3) A square patterned photoresist pattern was prepared on the two-dimensional tellurene surface baked in step (2) using electron beam lithography. After development and fixing, it was dried with nitrogen gas. The optical photograph of the two-dimensional tellurene after patterning photoresist is shown below. Figure 4 As shown in the left figure;

[0050] (4) Immerse the patterned substrate from step (3) in potassium permanganate solution for 3 minutes, then rinse with deionized water and dry with nitrogen gas; wherein, the preparation process of the potassium permanganate solution is as follows: weigh 10 mg of potassium permanganate and mix it with 400 ml of hydrochloric acid solution with a concentration of 30 mmol / L.

[0051] (5) The substrate soaked in potassium permanganate solution in step (4) is immersed in acetone solution at 80°C for 0.5 h. After removal, it is cleaned with deionized water to obtain patterned thinned two-dimensional tellurene. The optical microscope image of the patterned thinned two-dimensional tellurene film is shown below. Figure 4 As shown in the right figure.

[0052] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for patterned thinning of two-dimensional tellurene, characterized in that, The method includes the following steps: (1) Transfer the pre-prepared two-dimensional tellurene to the target substrate; (2) Spin-coat electron beam photoresist on the surface of the two-dimensional tellurene in the target substrate in step (1), bake after spin coating, and then use electron beam exposure method to pattern the electron beam photoresist on the surface of the two-dimensional tellurene. (3) The two-dimensional tellurene with patterned electron beam photoresist obtained in step (2) is immersed in an oxidant solution for a certain period of time to selectively thin the two-dimensional tellurene exposed in the patterned area. (4) First, use an organic solvent to remove the electron beam photoresist on the surface of the two-dimensional tellurene after step (3), then rinse with deionized water, and finally dry the cleaned two-dimensional tellurene at a certain temperature to obtain the patterned thinned two-dimensional tellurene. In step (3), the oxidant is any one of nitrous acid, hydrogen peroxide, or potassium permanganate. The soaking time in step (3) is 0.5-60 min; The method for removing the electron beam photoresist from the surface of the two-dimensional tellurene in step (4) is as follows: the two-dimensional tellurene treated in step (3) is immersed in acetone, an organic solvent at a temperature of 60-100℃, for 0.5-2 hours.

2. The method for patterned thinning of two-dimensional tellurene according to claim 1, characterized in that, The two-dimensional tellurene in step (1) is prepared by hydrothermal method or thermal evaporation method.

3. The method for patterned thinning of two-dimensional tellurene according to claim 2, characterized in that, The specific process of the hydrothermal method is as follows: First, weigh 0.5-3.0g of polyvinylpyrrolidone and 0.05-0.5g of sodium tellurite, dissolve them in 15-20ml of deionized water, and stir magnetically until the solution is clear; then, add 1-4ml of ammonia and 0.5-2.0ml of hydrazine hydrate to the clear solution in sequence, and continue to stir magnetically for 1min; finally, transfer the above solution to a 50ml hydrothermal reactor, and grow it in a constant temperature drying oven at 170℃-190℃ for 4-24h. After the reaction is completed, the product is centrifuged and washed multiple times to obtain the two-dimensional tellurene.

4. The method for patterned thinning of two-dimensional tellurene according to claim 2, characterized in that, The specific process of the thermal evaporation method is as follows: First, the substrate is surface-treated using plasma; then, gold colloidal particles are spin-coated onto the substrate surface at a rotation speed of 500-5000 rpm, and the substrate with spin-coated gold particles is transferred into the evaporation chamber; finally, the evaporation chamber is evacuated to a vacuum level of 5 × 10⁻⁶. -4 Below Pa, thermal evaporation begins, with tellurium metal particles used as the evaporation source for deposition. After deposition, the sample is removed to obtain the two-dimensional tellurene film.

5. The method for patterned thinning of two-dimensional tellurene according to claim 4, characterized in that, The plasma power is 10-100W, and the plasma treatment time is 0.5-5min; the diameter of the spin-coated gold colloidal particles is 10-100nm; the thermal evaporation deposition rate is 10-400nm / min, the deposition time is 5-120s, and the substrate rotation speed during the deposition process is 5-20rpm.

6. The method for patterned thinning of two-dimensional tellurene according to claim 1, characterized in that, In step (1), the target substrate is any one of the following: insulating silicon substrate, polyethylene terephthalate substrate, polyimide substrate, sapphire substrate, and ordinary glass substrate.

7. The method for patterned thinning of two-dimensional tellurene according to claim 1, characterized in that, In step (2), the electron beam photoresist is polymethyl methacrylate with a molecular weight of 950K; the baking conditions are: baking at a temperature of 100℃-180℃ for 1-5 minutes.

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