A method for controllable preparation of bubbles in two-dimensional materials based on ionizing radiation

Abstract

The application discloses a controllable preparation method of a two-dimensional material bubble based on ionizing radiation. First, a single-layer two-dimensional material sample is prepared through mechanical exfoliation and dry transfer process, then the sample is irradiated by using a low-energy alpha source, and subsequently, the sample is placed in a temperature control platform and annealed according to a preset program. After irradiation, small bubbles appear on the surface of the two-dimensional material, and after annealing, the small bubbles in the material gradually merge into larger bubbles under the action of heat and finally stabilize. The treated sample can be characterized by using an atomic force microscope and a photoluminescence spectrum, the size, shape and distribution of the bubbles are analyzed, and the influence of the local strain introduced by the bubbles on the spectral properties of the two-dimensional material is analyzed. The application provides a new method for introducing strain in a two-dimensional material, and through ionizing radiation technology and annealing treatment of the two-dimensional material, the size and shape of the bubbles are accurately controlled, and the optical properties of the material are significantly changed.

Description

Technical Field

[0001] This invention belongs to the field of materials science and nanotechnology, and relates to a method for preparing controllable bubbles in two-dimensional materials by combining irradiation technology with annealing process, which is particularly suitable for atomically thin two-dimensional semiconductor materials such as TMDCs. Background Technology

[0002] In recent years, monolayer two-dimensional transition metal sulfides (TMDCs) have attracted much attention due to their unique electrical, mechanical, and optical properties. They hold significant practical implications for controlling the properties of two-dimensional materials, expanding their application range, and opening up new areas of exploration in materials science and engineering. However, achieving this goal requires overcoming many practical challenges, including obtaining favorable mechanical, optical, and electromagnetic properties in two-dimensional materials.

[0003] Studies have shown that the thermal, electrical, mechanical, and optical properties of TMDCs can be effectively controlled through intrinsic structural factors such as the number of layers and stacking order, as well as external means such as voltage, strain, defects, and doping. However, existing control methods still have certain limitations due to difficulties in achieving active control and the introduction of contaminants, hindering the development and application of TMDCs in optoelectronic devices. To further meet the application needs of two-dimensional TMDCs materials and expand their application fields, finding effective means to control their physical properties has become a key scientific problem that urgently needs to be solved.

[0004] Traditional control methods, such as doping and setting fixed patterned substrates, limit their application in the field of two-dimensional material property control due to drawbacks such as introducing contamination or lack of real-time control. Ionizing radiation (IR), as a widely used irradiation method, has been extensively used to control the properties of various nanomaterials. It has advantages such as no chemical doping, no contact, controllability, and reversibility. Studying the interaction mechanism between radiation and two-dimensional materials and its application in property control is crucial. Currently, most research focuses on the impact of defects on two-dimensional materials after high-energy particle irradiation, while research on the non-destructive control of two-dimensional material properties by ionizing radiation is lacking. Meanwhile, optoelectronic devices based on two-dimensional TMDCs have broad application prospects in the aerospace field due to their advantages of small size, light weight, and low power consumption. Investigating the changes or damage of radiation conditions to the properties of two-dimensional materials is also of great application value for evaluating the working performance of related devices under operating conditions. Summary of the Invention

[0005] The purpose of this invention is to address the problems of contamination or lack of real-time control in traditional methods for controlling the properties of two-dimensional materials, and to provide a controllable preparation method for bubbles in two-dimensional materials based on ionizing radiation. This method involves preparing monolayer TMDCs, followed by twelve days of irradiation using a 5 MeV exempt-level α-plane source, and finally annealing to further achieve controllable bubble growth. The stress field generated by these bubbles can significantly alter the exciton luminescence intensity distribution and emission energy in the monolayer TMDCs, while simultaneously reducing the local roughness of the material. This method is applicable to a variety of two-dimensional materials, offering advantages of high efficiency and wide applicability, and providing a new avenue for the application of high-performance devices.

[0006] The technical solution of the present invention is as follows:

[0007] A controllable preparation method for bubbles in two-dimensional materials based on ionizing radiation, the method using an apparatus including an exemption-level alpha plane source, a temperature control console, and a computer; the preparation method includes:

[0008] Step 1: Prepare monolayer transition metal chalcogenides (TMDCs) on a reflective substrate by mechanical exfoliation and dry transfer;

[0009] Step 2: The prepared monolayer sample is placed on an exemption-level α-plane source for irradiation treatment. After irradiation treatment, microbubbles are generated on the surface of the material. These microbubbles are used as seed sources and their morphology is controlled by annealing.

[0010] Step 3: Place the irradiated sample in a computer-controlled temperature control console and anneal it according to the preset temperature and time program. After annealing, the tiny bubbles on the surface of the material will coalesce into larger bubbles under the action of heat.

[0011] Step 4: The irradiated sample can be characterized by atomic force microscopy and photoluminescence spectroscopy. The local strain introduced by the bubble can change the photoluminescence spectrum of monolayer TMDCs.

[0012] In the above method, the mechanical peeling step includes repeatedly sticking and peeling bulk crystal material with tape until a single layer of TMDCs is obtained.

[0013] In the above method, the single-layer TMDCs are single-layer WSe2, MoS2, WS2 or MoSe2.

[0014] In the above method, the dry transfer step involves transferring a single-layer TMDCs thin film onto a reflective substrate.

[0015] In the above method, the reflective substrate is a silicon dioxide / silicon substrate.

[0016] In the above method, the specific parameters of the exemption-level α-plane source are: energy 5 MeV, surface emissivity in the 2π direction: 5.71 × 10⁻⁶. 4 / min.

[0017] In the above method, the temperature control console is controlled by a computer and its functions include:

[0018] (1) A heating unit for providing the required heat;

[0019] (2) A cooling unit for controlling the cooling process;

[0020] (3) A temperature sensor for real-time temperature monitoring;

[0021] (4) A controller for controlling the heating and cooling units according to a preset temperature and time program.

[0022] In the above method, the temperature and time program for the annealing process specifically includes:

[0023] (1) Gradually increase the temperature from room temperature to 400K at a rate of 40K / min;

[0024] (2) Hold at 400K for 3 minutes;

[0025] (3) Cool down at a rate of 30 K / min, and stabilize for 3 minutes every 20 K decrease, until it reaches 80 K;

[0026] (4) After stabilizing at 80K for 3 minutes, restore to room temperature at a rate of 40K / min to complete one cycle;

[0027] In the above method, after the irradiated sample is annealed, the initial microbubbles existing in the monolayer gradually merge into larger bubbles under the action of heat, and eventually stabilize to form controllable bubbles.

[0028] In the above method, the characteristics of the bubble include:

[0029] (1) The bottom radius is 0.1 to 2 μm and the height is 10 to 100 nm;

[0030] (2) Its shape is spherical;

[0031] (3) Random distribution;

[0032] In the above method, the size, morphology, and distribution of bubbles in the two-dimensional material can be precisely measured using an atomic force microscope, and the photoluminescence signal of the material sample before and after irradiation is measured using photoluminescence spectroscopy, specifically including:

[0033] (1) Atomic force microscopes are used to measure the height, radius, and distribution of bubbles;

[0034] (2) Photoluminescence spectroscopy is used to analyze the effect of local strain introduced by bubbles on the photoluminescence properties of materials.

[0035] Advantages and beneficial effects of the present invention:

[0036] The present invention describes a method for preparing bubbles in controllable two-dimensional materials based on ionizing radiation. This method provides a novel approach to introducing strain into two-dimensional materials, enabling effective control over the size and morphology of bubbles. Annealing further improves the quality of the two-dimensional material crystals and reduces defects. Compared to traditional stress-introducing methods, this method eliminates the need for pre-prepared substrate patterns and cumbersome steps. Precise control of bubble growth can be achieved through simple irradiation and annealing processes. Furthermore, it overcomes the limitation of traditional methods where stress cannot be controlled due to the inability to modify the substrate, reducing preparation costs and increasing efficiency. This method is suitable for large-scale production and application, offering advantages such as non-contact, doping-free, and reversible controllability. It also significantly alters the optical properties of the material. In addition, this method is applicable to various two-dimensional materials, exhibiting broad applicability and versatility, providing a new avenue for developing novel high-performance devices, and possessing the advantages of high efficiency and high applicability. Attached Figure Description

[0037] Figure 1 The diagram shows a schematic of an irradiation and annealing treatment apparatus in a specific embodiment of the present invention, wherein: 1 is a computer, 2 is a temperature control console, 3 is a two-dimensional material monolayer sample, 4 is an alpha particle, and 5 is an exemption-level alpha standard source.

[0038] Figure 2 The left figure shows the trajectory of a monolayer irradiated with 5 MeV alpha particles, simulated using SRIM simulation software. The right figure shows the formation of defects in the sample, revealing that every 10 5 One vacancy is created by bombardment of one alpha particle.

[0039] Figure 3 The diagram shows the bubble generation before and after irradiation according to the present invention, wherein (a) is a single-layer sample without irradiation treatment, and (b) is a single-layer sample with bubbles generated after irradiation treatment. Helium gas was generated between the sample and the silicon substrate after irradiation.

[0040] Figure 4 The images show atomic force microscopy (AFM) scanning images of two-dimensional materials before and after irradiation in a specific embodiment of the present invention. (a) is a two-dimensional AFM scanning image of the two-dimensional material before irradiation, and (b) is an AFM scanning image after irradiation. It can be clearly observed that a large number of tiny protrusions are generated on the sample surface at the same location after irradiation.

[0041] Figure 5 Showing Figure 4 The bubble outline diagram in the white area is shown in (a) and (b), which are statistical diagrams of the height and width of different bubbles in this area. It can be seen that the bubbles are approximately semi-circular. (c) is the fitted curve of bubble height and width in (b), which shows that the bubble height and width have a linear relationship.

[0042] Figure 6 Atomic force microscopy (AFM) scanning images of two-dimensional materials before and after annealing are shown, where (a) and (b) are atomic force images before and after annealing, respectively, and (c) is a bubble profile before and after annealing.

[0043] Figure 7 The photoluminescence spectra of the samples before and after irradiation, as measured in Example 1 of the present invention, are shown. (b) shows the extraction of the peak positions of the photoluminescence spectrum in (a) to facilitate better observation of the redshift phenomenon in the spectrum. Detailed Implementation

[0044] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, so that those skilled in the art can more clearly understand the present invention.

[0045] This invention proposes a technique for generating seed bubbles using ionizing radiation and combining it with annealing to recombine microbubbles into controllable bubbles. This method involves multiple irradiations to initially accumulate microbubbles, followed by annealing to further control the size and morphology of the bubbles, providing a new approach for optimizing the performance of two-dimensional materials and their device applications. Specifically, theoretically, this invention has been demonstrated through SRIM simulations as a non-destructive irradiation technique. Experiments show that ionizing radiation generates microbubbles, and annealing causes the initial microbubbles in a monolayer of two-dimensional material to gradually merge into larger bubbles and eventually stabilize, thus forming a controllable artificial potential field on the surface of the two-dimensional material, thereby achieving effective control of two-dimensional exciton flow. This method not only improves the crystallinity of the material but also provides a new means to modulate the electronic and optical properties of two-dimensional materials.

[0046] The present invention proposes a controllable preparation method for bubbles in two-dimensional materials based on ionizing radiation, and the schematic diagram of the preparation apparatus used is shown below. Figure 1 As shown in the figure, 1 represents a computer, 2 a temperature control console, 3 a two-dimensional material monolayer sample, 4 alpha particles, and 5 an exemption-grade alpha standard source. The preparation method includes the following steps:

[0047] Step 1: Mechanically peel off monolayer TMDCs (such as WSe2) from the bulk crystal, using tape to repeatedly stick and peel until monolayer TMDCs material is obtained.

[0048] Step 2: Transfer the stripped monolayer TMDCs onto a polydimethylsiloxane (PDMS) substrate.

[0049] Step 3: Transfer the monolayer TMDCs on the PDMS substrate to the silicon dioxide / silicon substrate.

[0050] Step 4: Place the transferred monolayer TMDCs on an exemption-level α-plane source with an energy of 5 MeV for irradiation treatment over a period of twelve days.

[0051] Step 5: Place the prepared TMDCs thin-layer sample in a computer-controlled temperature control console (e.g., ...). Figure 1 As shown in the figure, the temperature control console includes a heating unit, a cooling unit, a temperature sensor, and a controller.

[0052] Step Six: Perform multiple annealing processes according to the preset temperature and time program. Specific steps include:

[0053] (1) Gradually increase the temperature from room temperature to 400K at a rate of 40K / min;

[0054] (2) Hold at 400K for 3 minutes;

[0055] (3) Cool down at a rate of 30 K / min, and stabilize for 3 minutes every 20 K decrease, until it reaches 80 K;

[0056] (4) After stabilizing at 80K for 3 minutes, restore to room temperature at a rate of 40K / min to complete one cycle;

[0057] Finally, a two-dimensional material bubble sample was obtained, such as... Figure 4 As shown in the scanning image obtained by atomic force microscopy.

[0058] The following describes the characterization method for the controllable two-dimensional material bubbles based on ionizing radiation technology and annealing treatment: In this invention, the height and radius of the controllable two-dimensional material bubbles based on ionizing radiation are measured using an atomic force microscope, and the changes in the size and morphology of the bubbles are analyzed, such as... Figure 5 and Figure 6 As shown; the photoluminescence spectra of the samples before and after irradiation were measured using a spectrometer to analyze the effect of local strain introduced by bubbles on the spectral properties of the material, such as... Figure 7 As shown.

[0059] Example 1

[0060] First, SRIM software was used to simulate the 5 MeV alpha particle irradiation of a two-dimensional material monolayer. It was found that every 10 5 One vacancy is created by bombardment with one alpha particle, thus proving that this technology is a non-destructive irradiation method.

[0061] Then, following the steps described above, a monolayer WSe2 sample is prepared, consisting of a silicon dioxide / silicon substrate and a monolayer WSe2, from bottom to top. Figure 3 As shown in (a).

[0062] The prepared WSe2 monolayer sample was first irradiated multiple times on an exemption-grade α-plane source, and the photoluminescence spectrum was measured after each irradiation using a spectrometer. The specific parameters of the exemption-grade α-plane source used here were: energy 5 MeV, and surface emissivity in the 2π direction: 5.71 × 10⁻⁶. 4 / min.

[0063] After the irradiation experiment, place it in a computer-controlled temperature control console (e.g., Figure 1 As shown in the figure, the temperature control console used here is a Linkam THMS600, which includes a heating unit, a cooling unit, a temperature sensor, and a controller.

[0064] Annealing is performed according to a preset temperature and time program, and the specific steps include:

[0065] (1) Gradually increase the temperature from room temperature to 400K at a rate of 40K / min;

[0066] (2) Hold at 400K for 3 minutes;

[0067] (3) Cool down at a rate of 30 K / min, and stabilize for 3 minutes every 20 K decrease, until it reaches 80 K;

[0068] (4) After stabilizing at 80K for 3 minutes, restore to room temperature at a rate of 40K / min to complete one cycle;

[0069] Finally, a two-dimensional material bubble sample was obtained. Figure 3 (a) and 3(b) record atomic force microscopy scanning images of monolayer WSe2 samples before and after irradiation.

[0070] Sample area ( Figure 3 The white dashed box in the image shows significant changes. A comparison of atomic force microscopy (AFM) scans before and after irradiation reveals the formation of numerous microbubbles. Further analysis using AFM to measure the bubble height and radius, and to examine the changes in bubble size and morphology in the monolayer WSe2 sample before and after annealing, is shown in the image. Figure 4 As shown, fitting the bubble height and width demonstrates a linear relationship. Comparison of atomic force microscopy scans before and after annealing reveals that the initial microbubbles gradually merge into larger bubbles under thermal action, such as... Figure 5 As shown in (a) and 5(b), Figure 5 (c) This phenomenon can be observed more intuitively.

[0071] The photoluminescence spectra of the samples before and after irradiation were measured using a spectrometer, such as... Figure 6 As shown, the spectral intensity first increases and then tends to stabilize with the increase of irradiation time, and the spectrum shows a redshift of about 0.7 meV. This indicates that the controllable two-dimensional material bubbles based on ionizing radiation treatment significantly changed the luminescence intensity and photoluminescence spectral position of the sample. This is due to the change in the band structure of the monolayer TMDCs caused by strain engineering.

[0072] This invention presents, for the first time, a controllable two-dimensional material bubble preparation method based on ionizing radiation. The method generates initial bubbles through a single layer of ionizing radiation. Repeated irradiation continuously alters the optical properties of the two-dimensional material, and annealing further allows for the control of bubble size and morphology. This method provides a novel approach to introducing strain into two-dimensional materials, significantly changing their electronic and optical properties. Specifically, helium gas is generated through ionizing radiation, followed by annealing. The initial microbubbles gradually merge into larger bubbles under thermal influence and eventually stabilize, forming a controllable artificial potential field, thereby enabling active manipulation of exciton flow. This method offers advantages such as being contactless, doped-free, reversible, and controllable, and is applicable to various two-dimensional materials, including WSe2, MoS2, WS2, and MoSe2. Besides exciton flow manipulation, this method is also suitable for optimizing the properties of other materials, such as in electronic devices, optoelectronic devices, and quantum information processing. The increasing demand for high-performance two-dimensional materials in materials science and nanotechnology provides strong support and reference value for the development of these fields.

[0073] Finally, it should be noted that the purpose of disclosing the embodiments is to help further understand the present invention. Those skilled in the art should understand that various substitutions and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the content disclosed in the embodiments, and the scope of protection of the present invention is defined by the claims.

Claims

1. A controllable preparation method for bubbles in a two-dimensional material based on ionizing radiation, characterized in that, include: Step 1: Prepare a monolayer of transition metal chalcogenide on a reflective substrate by mechanical exfoliation and dry transfer; Step 2: The prepared monolayer sample is placed on an exemption-grade α-plane source for irradiation. The specific parameters of the exemption-grade α-plane source are: energy 5 MeV, surface emissivity in the 2π direction: 5.71 × 10⁻⁶. 4 / min, after irradiation treatment, tiny bubbles are generated on the surface of the material; Step 3: Place the irradiated sample in a computer-controlled temperature control console and perform annealing according to the preset temperature and time program. The specific temperature and time program for annealing includes: (1) Gradually increase the temperature from room temperature to 400 K at a rate of 40 K / min; (2) Hold at 400 K for 3 minutes; (3) Cool at a rate of 30 K / min and stabilize for 3 minutes every 20 K decrease until it reaches 80 K; (4) After stabilizing at 80 K for 3 minutes, restore to room temperature at a rate of 40 K / min to complete one cycle; After annealing, the tiny bubbles on the material surface coalesce into larger bubbles under heat, and eventually stabilize to form controllable bubbles; the characteristics of these bubbles include: (1) The bottom radius is 0.1~2 μm and the height is 10~100 nm; (2) Its shape is spherical; (3) Random distribution.

2. The method as described in claim 1, characterized in that, The monolayer transition metal chalcogenide is a monolayer tungsten diselenide, a monolayer molybdenum disulfide, a monolayer tungsten disulfide, or a monolayer molybdenum diselenide.

3. The method as described in claim 1, characterized in that, The reflective substrate is a silicon dioxide / silicon substrate.

4. The method as described in claim 1, characterized in that, The size, morphology, and distribution of bubbles in the two-dimensional material were precisely measured using atomic force microscopy. The photoluminescence signals of the material samples before and after irradiation were measured using photoluminescence spectroscopy, specifically including: (1) The height and radius of the bubble were measured using an atomic force microscope; (2) Photoluminescence spectroscopy analysis of the effect of local strain introduced by bubbles on the photoluminescence properties of materials.

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