A device and method for preparing a crystal direction controllable two-dimensional material based on directional mechanical exfoliation

Abstract

The application belongs to the technical field of two-dimensional material preparation, and specifically discloses a preparation device and method of crystal direction controllable two-dimensional material based on directional mechanical exfoliation, which comprises a bearing platform, an XYZ three-axis electric displacement table, a rigid cantilever, a first exfoliation tape, a first clamping piece, an observation window, an XYR electric displacement table, a square bearing frame, a boss, a second exfoliation tape and a second clamping piece, the first exfoliation tape is arranged across the observation window of the rigid cantilever, the second exfoliation tape is arranged across the boss, the in-plane relative angle of the two exfoliation tapes is adjusted through the R axis, the position alignment of the two-dimensional material crystal is completed through the X axis and the Y axis, the horizontal and rotational degrees of freedom are locked after alignment, and the contact and separation are completed only through the Z axis. The application can reduce the influence of the bending, twisting and in-plane sliding of the exfoliation tape on the crystal direction of the two-dimensional material, inhibit the random in-plane rotation of the two-dimensional material in the mechanical exfoliation process, and realize the preparation of the crystal direction controllable two-dimensional material.

Description

Technical Field

[0001] This invention relates to the field of two-dimensional material preparation technology, and in particular to an apparatus and method for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation. Background Technology

[0002] Two-dimensional materials have been widely used in quantum devices, electronic devices, and optoelectronic devices due to their excellent electrical, optical, and mechanical properties. For two-dimensional materials with in-plane anisotropy (such as black phosphorus and ReS2), different crystal orientations exhibit different characteristics in terms of carrier transport, light absorption, and mechanical response. Therefore, the control of the crystal orientation and its relative angles of two-dimensional materials directly affects the material performance and device response.

[0003] Traditional mechanical exfoliation with adhesive tape is one of the most commonly used methods for preparing high-quality two-dimensional material thin layers. It utilizes the van der Waals forces between the adhesive tape and the layered crystalline material, repeatedly applying and separating the tape to thin the bulk crystal to atomic-level thickness. However, traditional methods typically rely on manual application and separation of the tape, making the process highly susceptible to human error. More importantly, during mechanical exfoliation, the bending and twisting of the tape, as well as the random in-plane rotation of the crystal during the process, can cause uncontrollable shifts in the crystal orientation of the resulting two-dimensional material relative to the original bulk crystal. Studies have shown that even within the same mechanically exfoliated sample, significant misalignment of the crystal axis can be observed in different regions.

[0004] While some improved mechanical peeling devices exist in the prior art, which can enhance the stability of the peeling process to some extent, their control over the crystal orientation of two-dimensional materials still needs improvement. Specifically, the maintenance of crystal orientation during the mechanical peeling of two-dimensional materials is closely related to the relative position, in-plane angle, and contact and separation processes of the two peeling tapes. Increasing the rigidity of the tape's supporting structure to reduce the effects of bending and torsion of the flexible tape, and precisely adjusting the position and relative in-plane angle of the two peeling tapes, while limiting the contact area and separation direction during the peeling process, will help reduce the random in-plane rotation of the two-dimensional material crystals during peeling, thus making it possible to achieve directional mechanical peeling of two-dimensional materials with controllable crystal orientation.

[0005] Therefore, adjusting the position and in-plane relative angle of the crystal during the mechanical exfoliation of two-dimensional materials, and restricting its in-plane movement after alignment, is a feasible method to obtain two-dimensional materials with controllable crystal orientation, but relevant technical means are currently lacking. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an apparatus and method for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation.

[0007] To achieve the above objectives, the present invention is implemented according to the following technical solution: The first technical solution provided by this invention is a device for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation, including a support platform and a first positioning component and a second positioning component disposed on the support platform; The first positioning component includes an XYZ three-axis electric displacement stage and a rigid cantilever assembly mounted on a bearing platform. The rigid cantilever assembly includes a rigid cantilever, a first release tape for supporting two-dimensional material crystals, and two first clamping members. The rigid cantilever is fixedly mounted on the Z-axis motion output bearing surface of the XYZ three-axis electric displacement stage. The rigid cantilever has an observation window. The first release tape spans across the observation window. The two first clamping members are respectively located on opposite sides of the observation window on the lower end face of the rigid cantilever, clamping and fixing the first release tape onto the rigid cantilever. The second positioning component includes an XYR electric displacement stage and a second peeling tape carrier component mounted on a support platform below a rigid cantilever. The second peeling tape carrier component includes a square support frame, a boss fixed to the center of the square support frame, a second peeling tape, and two second clamping members. The square support frame is fixedly mounted on the R-axis rotation output support surface of the XYR electric displacement stage. The second peeling tape spans across the boss, and the two second clamping members are respectively located on the upper surfaces of the square support frame on opposite sides of the boss, fixing the second peeling tape to the square support frame so that the second peeling tape covers the top of the boss and remains taut. The R-axis of the XYR electric displacement stage is used to adjust the in-plane relative angle between the first and second release tapes. The horizontal motion axes of the XYZ three-axis electric displacement stage and the XYR electric displacement stage are used to align the two-dimensional material crystals on the first release tape with the top of the boss. After the position and angle alignment is completed, the horizontal motion axes and R-axis of the XYZ three-axis electric displacement stage and the XYR electric displacement stage remain locked, and only the Z-axis of the XYZ three-axis electric displacement stage provides the contact displacement and separation displacement between the first and second release tapes.

[0008] Furthermore, both the first and second release tapes are formed by stacking at least two layers of transparent polymer tape, wherein the thickness of a single layer of the transparent polymer tape is 50-150 μm, and the thickness after stacking is not less than 150 μm.

[0009] Furthermore, the top of the boss is flat, and at least two opposite sides of the boss are inclined surfaces.

[0010] Furthermore, both of the first clamping members and the two second clamping members are parallel elongated pressure plates, which are mounted on the upper surfaces of the square support frames on opposite sides of the observation window or on opposite sides of the boss by screws.

[0011] Furthermore, the XYZ three-axis electric displacement stage and the XYR electric displacement stage are detachably attached to the support platform via switchable magnetic fixing seats.

[0012] Preferably, the R-axis rotation center of the XYR electric displacement stage coincides with the center of the boss. Of course, if the R-axis rotation center of the XYR electric displacement stage does not coincide with the center of the boss, the XYR electric displacement stage will compensate for its position using the X and Y axes based on the eccentricity between the R-axis rotation center and the boss center.

[0013] Furthermore, the apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation also includes a nitrogen glove box or an argon glove box. The apparatus is placed inside the nitrogen glove box or argon glove box for contacting and separating black phosphorus crystals. The glove box serves as the external operating environment for the apparatus. The oxygen and water content inside the glove box are not higher than 100 ppm, and the black phosphorus two-dimensional material sample is sealed inside the glove box after it is obtained.

[0014] The second technical solution provided by this invention is a method for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation. The method employs the aforementioned apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation to perform mechanical exfoliation of the two-dimensional material, and includes the following steps: S1. Place the two-dimensional material crystal on the surface of the first release tape and adhere and fix it; then place the first release tape across the observation window of the rigid cantilever and fix it by two first clamping members; S2. The second peeling tape is placed across the boss of the second tape carrying assembly and fixed by two second clamping members; S3. Determine the crystal orientation of the two-dimensional material crystal and record the crystal orientation angle of the determined crystal orientation relative to the first release tape; S4. Adjust the in-plane relative angle between the first and second peeling tapes by the R-axis of the XYR electric displacement stage, and align the two-dimensional material crystal, the observation window and the top of the boss with each other by at least one of the horizontal motion axes of the XYZ three-axis electric displacement stage and the XYR electric displacement stage. S5. After completing the position and angle alignment, lock the X and Y axes of the XYZ three-axis electric displacement stage and the X, Y and R axes of the XYR electric displacement stage, and drive only the Z axis of the XYZ three-axis electric displacement stage so that the two-dimensional material crystal on the first release tape contacts the second release tape at the top of the boss. S6. Keeping the in-plane relative angle and horizontal relative position between the first and second release tapes unchanged, drive the Z-axis to move in the opposite direction, so that the first and second release tapes separate in a direction perpendicular to the tape contact surface; repeat the position alignment, contact and separation process according to the required two-dimensional material thickness to obtain the two-dimensional material sample after peeling. S7. Release the clamping member corresponding to the release tape carrying the two-dimensional material sample, remove the release tape carrying the two-dimensional material sample from the orientation mechanical release device and install it to the substrate transfer station, so that the two-dimensional material sample comes into contact with the target substrate and then remove the release tape, transfer the two-dimensional material sample to the target substrate, and obtain a crystal orientation controllable two-dimensional material.

[0015] Furthermore, the target substrate includes a SiO2 / Si substrate, a sapphire substrate, a quartz substrate, a flexible polydimethylsiloxane substrate, a flexible polyimide substrate, and a flexible bisphenol A carbonate substrate. When the target substrate is a SiO2 / Si substrate, a release tape or a detachable tape clamping module carrying the two-dimensional material sample is installed at the SiO2 / Si substrate transfer station. After the two-dimensional material sample comes into contact with the SiO2 / Si substrate, the release tape is removed, and the two-dimensional material sample is transferred to the SiO2 / Si substrate.

[0016] Furthermore, the Z-axis of the XYZ triaxial electric displacement stage separates the first and second release tapes at a speed of 0.1-10 μm / s, and uses an acceleration lower than that of the constant speed separation stage during the start-up and stop phases.

[0017] Furthermore, when the two-dimensional material crystal is black phosphorus crystal, angle-resolved polarization Raman measurement is performed using a confocal Raman spectrometer outside the directional mechanical exfoliation device. The polarization direction of the incident light or the sample orientation is changed within the range of 0°-180°, and the black phosphorus crystal A is recorded. 2 The Raman intensity of at least one of the g-mode and B2g-mode varies with the polarization angle, and the relationship between the Raman intensity and the angle is fitted using a function with a period of 180° to determine the armchair orientation or zigzag orientation of the black phosphorus crystal and the corresponding crystal orientation angle. The determined crystal orientation is recorded relative to the first release tape. The contact and separation of the black phosphorus crystal are carried out in a nitrogen glove box or an argon glove box, wherein the oxygen content and water content in the glove box are not higher than 100 ppm, and the black phosphorus two-dimensional material sample is sealed in the glove box after obtaining the sample.

[0018] Compared with existing technologies, this invention constructs a directional mechanical peeling device comprising an XYZ triaxial electric displacement stage, an XYR electric displacement stage, a rigid cantilever assembly, and a second tape-bearing assembly. The rigid cantilever and clamping structure limit the bending and in-plane twisting of the first peeling tape, and the boss defines the local contact area between the first and second peeling tapes. Simultaneously, the XYZ triaxial electric displacement stage and the XYR electric displacement stage adjust the position of the two-dimensional material crystal and the in-plane relative angle between the two peeling tapes. After position and angle alignment, the horizontal and R axes are locked, retaining only the Z-axis motion to complete the contact and separation of the two peeling tapes. This reduces crystal orientation shift caused by tape bending, twisting, in-plane slippage, and random in-plane rotation of the two-dimensional material crystal during peeling, improving the stability of crystal orientation maintenance during the mechanical peeling of two-dimensional materials and enabling the preparation of crystal-oriented two-dimensional materials. Furthermore, by adjusting the peeling tape structure, the in-plane relative angle between the two peeling tapes, and the motion parameters during contact and separation, the crystal orientation deviation during the mechanical peeling of two-dimensional materials can be further controlled. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation according to the present invention.

[0020] Figure 2 This is a schematic diagram showing the positional relationship between the rigid cantilever assembly and the second peeling tape carrier assembly near the working height.

[0021] Figure 3 This is a front structural diagram of a rigid cantilever assembly.

[0022] Figure 4 This is a schematic diagram of the rear structure of a rigid cantilever assembly.

[0023] Figure 5 This is a schematic diagram of the structure of the second peeling tape carrier assembly.

[0024] Figure 6 A physical image of the bulk black phosphorus crystals used in the implementation method.

[0025] Figure 7 An optical microscope image of the black phosphorus crystal used in the embodiment.

[0026] Figure 8 Raman spectrum of black phosphorus crystal used in the implementation method.

[0027] Figure 9 Black phosphorus crystal A used in the implementation method 2 The result of the g-mode intensity varying with the polarization angle is shown in the figure.

[0028] In the figure, the following labels are used: 1-XYZ three-axis electric displacement stage; 2-XYR electric displacement stage; 3-rigid cantilever assembly; 31-rigid cantilever; 32-observation window; 33-first clamping member; 4-second peeling tape carrier assembly; 41-square carrier frame; 42-boss; 43-second clamping member. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0030] Unless otherwise specified, all materials and reagents used in the following examples are commercially available; and all techniques and methods used are conventional in the field unless otherwise specified.

[0031] Example 1: As Figures 1-5 As shown in the figure, this embodiment exemplarily demonstrates a fabrication apparatus for crystal orientation controllable two-dimensional materials based on directional mechanical exfoliation, including a support platform (not shown in the figure) and a first positioning component and a second positioning component disposed on the support platform. In this embodiment, the support platform is an optical platform with a hole array. The XYZ triaxial electric displacement stage 1 (commercially available) and the XYR electric displacement stage 2 (commercially available) are detachably adsorbed onto the support platform by switchable magnetic fixing seats and are staggered on the support platform. To improve the repeatability of the XYZ triaxial electric displacement stage 1 and the XYR electric displacement stage 2 after disassembly and assembly, the position and angle of the switchable magnetic fixing seats can be limited by the optical platform hole array, positioning pins, or limiting blocks. like Figure 1 , Figure 3 and Figure 4 As shown, the first positioning component includes an XYZ three-axis electric displacement stage 1 and a rigid cantilever assembly 3 mounted on a support platform. The rigid cantilever assembly 3 includes a rigid cantilever 31, a first release tape (not shown in the figure) for supporting two-dimensional material crystals, and two first clamping members 33. The rigid cantilever 31 is mounted to the Z-axis motion output bearing surface of the XYZ three-axis electric displacement stage 1 by screws. The rigid cantilever 31 has a circular observation window 32. The first release tape spans across the observation window 32. The two first clamping members 33 are respectively arranged on opposite sides of the observation window 32 on the lower end face of the rigid cantilever 31 to clamp and fix the first release tape on the rigid cantilever 31. The rigid cantilever 31 is used to limit the overall bending and in-plane torsion of the first release tape. The symmetrically arranged first clamping members 33 can reduce the uneven force on both sides of the first release tape. like Figure 1 and Figure 5As shown, the second positioning component includes an XYR electric displacement stage 2 and a second peeling tape carrier component 4 mounted on a bearing platform below the rigid cantilever 31. The second peeling tape carrier component 4 includes a square bearing frame 41, a boss 42 fixed to the center of the square bearing frame, a second peeling tape (not shown in the figure), and two second clamping members 43. The square bearing frame 41 is fixedly mounted on the R-axis rotation output bearing surface of the XYR electric displacement stage 2. In this embodiment, the R-axis rotation center of the XYR electric displacement stage 2 coincides with the center of the boss 42. The second release tape spans across the boss 42. The top of the boss 42 is flat, and at least two opposite sides of the boss 42 are inclined. Two second clamping members 43 are respectively located on the upper surface of the square support frame 41 on opposite sides of the boss 42, fixing the second release tape to the square support frame 41 so that the second release tape covers the top of the boss 42 and remains taut. The boss 42 is used to define the local contact area between the first release tape and the second release tape, thereby improving the stability of the tape structure and contact position during the mechanical peeling of two-dimensional material crystals. The X and Y axes of the XYZ three-axis electric displacement stage 1 are used to change the position of the two-dimensional material crystal on the first release tape relative to the observation window 32 and the boss 42, and the Z axis is used to change the vertical distance between the first release tape and the second release tape. The X and Y axes of the XYR electric displacement stage 2 are used to move the boss 42 below the observation window 32, and the R axis is used to adjust the in-plane angle of the second release tape relative to the first release tape. The in-plane relative angle between the first release tape and the second release tape is preset to be 0°, 90° or other preset non-zero angle. In this embodiment, the X and Y axes of the XYZ three-axis electric displacement stage 1 and the X, Y and R axes of the XYR electric displacement stage 2 are respectively provided with a motor braking structure, a mechanical locking structure or a holding drive structure (the motor braking structure, mechanical locking structure or holding drive structure is provided by the manufacturer) so that the horizontal motion axis and the R axis remain locked during the contact and separation process in the Z direction after the position and angle alignment is completed.

[0032] The R-axis of the XYR electric displacement stage 2 is used to adjust the in-plane relative angle between the first and second release tapes. The horizontal motion axes of the XYZ three-axis electric displacement stage 1 and the XYR electric displacement stage 2 are used to align the two-dimensional material crystals on the first release tape with the top of the boss 42. After the position and angle alignment is completed, the horizontal motion axes and R-axis of the XYZ three-axis electric displacement stage 1 and the XYR electric displacement stage 2 are locked. The separation of the first and second release tapes is completed only by the Z-axis of the XYZ three-axis electric displacement stage 1 at a speed of 0.1-10 μm / s, and the acceleration is lower than that of the constant speed separation stage during the start and stop phases. During the actual peeling process, the boss 42 is moved below the observation window 32, so that the first and second release tapes only form local contact within the observation window 32, and the separation front is generated from the edge of the contact area at the top of the boss 42.

[0033] In this embodiment, both the first and second release tapes are formed by stacking at least two layers of transparent polymer tape. The thickness of a single layer of transparent polymer tape is 50-150 μm, and the thickness after stacking is not less than 150 μm.

[0034] The two first clamping members 33 and the two second clamping members 43 are all parallel long strip-shaped pressure plates. The long strip-shaped pressure plates are installed on the upper surface of the square support frame 41 on the opposite sides of the observation window 32 or the opposite sides of the boss 42 by screws.

[0035] In some embodiments, when the two-dimensional material crystal is black phosphorus crystal, the apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation in this embodiment further includes a nitrogen glove box or an argon glove box. The apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation is placed inside the nitrogen glove box or argon glove box for contacting and separating the black phosphorus crystal. The glove box is the external operating environment of the apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation. Angle-resolved polarization Raman measurement is performed using a confocal Raman spectrometer outside the directional mechanical exfoliation apparatus. The polarization direction of the incident light or the orientation of the sample is changed within the range of 0°-180°, and the black phosphorus crystal A is recorded. 2 The Raman intensity of at least one of the g-mode and B2g-mode varies with the polarization angle. The relationship between the Raman intensity and the angle is fitted using a function with a period of 180° to determine the armchair orientation or zigzag orientation of the black phosphorus crystal and the corresponding crystal orientation angle. The determined crystal orientation is recorded relative to the first release tape. The contact and separation of the black phosphorus crystal are carried out in a nitrogen glove box or an argon glove box. The oxygen content and water content in the glove box are not higher than 100 ppm, respectively. After obtaining the two-dimensional black phosphorus material sample, it is sealed in the glove box.

[0036] Example 2: This example uses black phosphorus crystal as a two-dimensional material example to illustrate the method of crystal orientation measurement and R-axis angle setting in the preparation method of crystal orientation controllable two-dimensional materials based on directional mechanical exfoliation; the specific process is as follows: (1) Adhere the bulk black phosphorus crystal to the first release tape, and use a confocal Raman spectrometer outside the mechanical release device to perform angle-resolved polarization Raman measurement. Change the polarization direction of the incident light or the orientation of the sample within the range of 0°-180°, and record the black phosphorus crystal A. 2 Raman intensity of g-mode and / or B2g-mode as a function of polarization angle, and determine the armchair or zigzag orientation of black phosphorus crystals based on the polarization configuration adopted.

[0037] (2) Record the measured black phosphorus crystal orientation relative to the edge of the first release tape, and adjust the in-plane angle of the second release tape relative to the crystal orientation reference using the R-axis of the XYR electric displacement stage 2. When the center of rotation of the R-axis coincides with the center of the boss 42, the angle is adjusted directly; when there is an eccentricity between the center of rotation of the R-axis and the center of the boss 42, the positional change caused by the angle adjustment is compensated by the X-axis and Y-axis of the XYR electric displacement stage 2.

[0038] Figure 6 This is a photograph of the bulk black phosphorus crystals used in this embodiment. Figure 7 This is an optical microscope image of black phosphorus crystals. Figure 8 This is the Raman spectrum of the black phosphorus crystal used in this embodiment. (From...) Figure 8 It can be seen that the black phosphorus crystal used exhibits typical black phosphorus Raman characteristic peaks, which can be used for angle-resolved polarized Raman testing and crystal orientation determination.

[0039] Figure 9 The black phosphorus crystal A used in this embodiment 2 Test results of the g-peak intensity varying with polarization angle. Figure 9 It can be seen that A 2 The intensity of the g-peak changes significantly with the polarization angle, reaching a maximum value around 145° and a minimum value around 90°. The maximum value corresponds to the armrest direction of the black phosphorus crystal, and the minimum value corresponds to the zigzag direction. Based on this, the crystal orientation of the black phosphorus crystal is determined, and the in-plane relative angle between the second release tape and the black phosphorus crystal on the first release tape is set by the R-axis of the XYR electric displacement stage 2.

[0040] Example 3: This example uses black phosphorus crystals as a two-dimensional material example to illustrate the method for preparing two-dimensional materials with controllable crystal orientation using the apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation described in Example 1; the specific process is as follows: (1) Using the X-axis and Y-axis of the XYZ three-axis electric displacement stage 1, the target black phosphorus crystal on the first peeling tape is moved to the projection range of the top of the boss 42 through the observation window 32; if necessary, the position of the boss 42 is compensated by the X-axis and Y-axis of the XYR electric displacement stage 2, so that the target black phosphorus crystal, the observation window 32 and the top of the boss 42 are aligned with each other.

[0041] (2) After completing the alignment of the position and in-plane angle of the black phosphorus crystal, lock the X-axis and Y-axis of the XYZ three-axis electric displacement stage 1, and lock the X-axis, Y-axis and R-axis of the XYR electric displacement stage 2; then drive only the Z-axis of the XYZ three-axis electric displacement stage 1 to descend, so that the target black phosphorus crystal contacts the second stripping tape at the top of the boss 42.

[0042] (3) After the contact is held for a preset time, only the Z-axis of the XYZ three-axis electric displacement stage 1 is driven to move in the opposite direction at 0.1-10 μm / s to separate the first and second stripping tapes. During the separation process, the in-plane relative angle and horizontal relative position of the two stripping tapes remain unchanged. The Z-axis adopts an acceleration lower than that in the constant speed separation stage during the start-up and stop phases to reduce the vibration of the stripping tapes and the micro-slippage of the platform caused by inertial impact, thereby completing the directional mechanical stripping of the black phosphorus crystals.

[0043] The separation method described above is a Z-axis separation perpendicular to the contact surface of the first and second peeling tapes. After the position and angle alignment of the black phosphorus crystals are completed, the X, Y, and R axes are locked, and only the Z-axis movement is retained to maintain the in-plane crystal orientation relationship of the black phosphorus set before peeling. The Z-axis direction is only the direction of movement of the two peeling tapes in contact and separation, and does not mean that the Z-axis direction is parallel to the armrest direction or zigzag direction of the black phosphorus crystals.

[0044] Example 4: This example uses black phosphorus crystals as a two-dimensional material example to illustrate the glove box operation and the method of transferring two-dimensional materials to a substrate using a method for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation; the specific process is as follows: (1) The apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation is placed in a nitrogen glove box or an argon glove box for contacting and separating black phosphorus crystals. The glove box is the external operating environment of the apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation. The oxygen content and water content in the glove box are controlled to be below 100 ppm, respectively; in an embodiment that further reduces the influence of black phosphorus oxidation, the oxygen content and water content are controlled to be below 10 ppm, respectively.

[0045] (2) After separation, release the corresponding first clamping member 33 or second clamping member 43 according to the location of the black phosphorus stripping sample, remove the stripping tape carrying the black phosphorus stripping sample from the preparation device of crystal orientation controllable two-dimensional material based on directional mechanical stripping, and install the stripping tape or detachable tape clamping module to the SiO2 / Si substrate transfer station.

[0046] (3) Make the black phosphorus stripping sample contact with the SiO2 / Si substrate, keep it for a preset time, and then remove the stripping tape to transfer the black phosphorus stripping sample to the SiO2 / Si substrate; then encapsulate the transferred black phosphorus thin layer in the glove box, and then use the confocal Raman spectrometer outside the mechanical stripping device to verify the crystal orientation of the black phosphorus thin layer.

[0047] In summary, this invention employs a directional mechanical peeling method, combining a rigid tape support structure, an XYZ triaxial electric displacement stage, and an XYR electric displacement stage to adjust the position and in-plane relative angles of the two-dimensional material during the mechanical peeling process. After achieving position and crystal orientation alignment, the in-plane motion degrees of freedom are locked, retaining only the Z-axis motion to complete contact and separation. This reduces crystal orientation shifts caused by tape bending, twisting, and in-plane rotation during peeling, enabling the preparation of crystal orientation-controllable two-dimensional materials. Furthermore, by adjusting the peeling tape structure, crystal orientation angles, contact positions, and motion parameters during peeling, the stability and crystal orientation consistency of the directional mechanical peeling process of two-dimensional materials can be further improved.

[0048] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. An apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation, comprising a support platform and a first positioning component and a second positioning component disposed on the support platform; characterized in that: The first positioning component includes an XYZ three-axis electric displacement stage and a rigid cantilever assembly mounted on a bearing platform. The rigid cantilever assembly includes a rigid cantilever, a first release tape for supporting two-dimensional material crystals, and two first clamping members. The rigid cantilever is fixedly mounted on the Z-axis motion output bearing surface of the XYZ three-axis electric displacement stage. The rigid cantilever has an observation window. The first release tape spans across the observation window. The two first clamping members are respectively located on opposite sides of the observation window on the lower end face of the rigid cantilever, clamping and fixing the first release tape onto the rigid cantilever. The second positioning component includes an XYR electric displacement stage and a second peeling tape carrier component mounted on a support platform below a rigid cantilever. The second peeling tape carrier component includes a square support frame, a boss fixed to the center of the square support frame, a second peeling tape, and two second clamping members. The square support frame is fixedly mounted on the R-axis rotation output support surface of the XYR electric displacement stage. The second peeling tape spans across the boss, and the two second clamping members are respectively located on the upper surfaces of the square support frame on opposite sides of the boss, fixing the second peeling tape to the square support frame so that the second peeling tape covers the top of the boss and remains taut. The R-axis of the XYR electric displacement stage is used to adjust the in-plane relative angle between the first and second release tapes. The horizontal motion axes of the XYZ three-axis electric displacement stage and the XYR electric displacement stage are used to align the two-dimensional material crystals on the first release tape with the top of the boss. After the position and angle alignment is completed, the horizontal motion axes and R-axis of the XYZ three-axis electric displacement stage and the XYR electric displacement stage remain locked, and only the Z-axis of the XYZ three-axis electric displacement stage provides the contact displacement and separation displacement between the first and second release tapes.

2. The apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation according to claim 1, characterized in that: Both the first and second release tapes are formed by laminating at least two layers of transparent polymer tape, wherein the thickness of a single layer of the transparent polymer tape is 50-150 μm, and the thickness after lamination is not less than 150 μm.

3. The apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation according to claim 1, characterized in that: The top of the boss is flat, and at least two opposite sides of the boss are inclined surfaces.

4. The apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation according to claim 1, characterized in that: The two first clamping members and the two second clamping members are both parallel elongated pressure plates, which are installed on the upper surface of the square support frame on opposite sides of the observation window or on opposite sides of the boss by screws.

5. The apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation according to claim 1, characterized in that: The XYZ three-axis electric displacement stage and the XYR electric displacement stage are detachably attached to the support platform via switchable magnetic mounting bases.

6. The apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation according to claim 1, characterized in that: The R-axis rotation center of the XYR electric displacement stage coincides with the center of the boss.

7. The apparatus for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation according to claim 1, characterized in that: It also includes a nitrogen glove box or an argon glove box. The preparation device for the crystal orientation controllable two-dimensional material based on directional mechanical exfoliation is placed in the nitrogen glove box or argon glove box for contacting and separating black phosphorus crystals. The glove box is the external operating environment of the preparation device for the crystal orientation controllable two-dimensional material based on directional mechanical exfoliation. The oxygen content and water content in the glove box are not higher than 100 ppm, and the black phosphorus two-dimensional material sample is sealed in the glove box after it is obtained.

8. A method for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation, characterized in that, The mechanical exfoliation of two-dimensional materials using the apparatus for preparing crystal orientation controllable two-dimensional materials based on directional mechanical exfoliation as described in any one of claims 1-7 includes the following steps: S1. Place the two-dimensional material crystal on the surface of the first release tape and adhere and fix it; then place the first release tape across the observation window of the rigid cantilever and fix it by two first clamping members; S2. The second peeling tape is placed across the boss of the second tape carrying assembly and fixed by two second clamping members; S3. Determine the crystal orientation of the two-dimensional material crystal and record the crystal orientation angle of the determined crystal orientation relative to the first release tape; S4. Adjust the in-plane relative angle between the first and second peeling tapes by the R-axis of the XYR electric displacement stage, and align the two-dimensional material crystal, the observation window and the top of the boss with each other by at least one of the horizontal motion axes of the XYZ three-axis electric displacement stage and the XYR electric displacement stage. S5. After completing the position and angle alignment, lock the X and Y axes of the XYZ three-axis electric displacement stage and the X, Y and R axes of the XYR electric displacement stage, and drive only the Z axis of the XYZ three-axis electric displacement stage so that the two-dimensional material crystal on the first release tape contacts the second release tape at the top of the boss. S6. Keeping the in-plane relative angle and horizontal relative position between the first and second release tapes unchanged, drive the Z-axis to move in the opposite direction, so that the first and second release tapes separate in a direction perpendicular to the tape contact surface; repeat the position alignment, contact and separation process according to the required two-dimensional material thickness to obtain the two-dimensional material sample after peeling. S7. Release the clamping member corresponding to the release tape carrying the two-dimensional material sample, remove the release tape carrying the two-dimensional material sample from the orientation mechanical release device and install it to the substrate transfer station, so that the two-dimensional material sample comes into contact with the target substrate and then remove the release tape, transfer the two-dimensional material sample to the target substrate, and obtain a crystal orientation controllable two-dimensional material.

9. The method for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation according to claim 8, characterized in that: The target substrates include SiO2 / Si substrates, sapphire substrates, quartz substrates, flexible polydimethylsiloxane substrates, flexible polyimide substrates, and flexible polybisphenol A carbonate substrates.

10. The method for preparing two-dimensional materials with controllable crystal orientation based on directional mechanical exfoliation according to claim 1, characterized in that: The Z-axis of the XYZ triaxial electric displacement stage separates the first and second release tapes at a speed of 0.1-10 μm / s, and uses an acceleration lower than that of the constant speed separation stage during the start-up and stop phases.

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