Device capable of accurately controlling stacking angle of two-dimensional material in ultrahigh vacuum environment

Abstract

The utility model discloses a device capable of accurately controlling the stacking angle of two-dimensional materials in an ultrahigh vacuum environment. The device comprises an ultra-vacuum cavity one-dimensional linear conveying rod and a rotatable sample frame, the rotatable sample frame comprises a sample table and a driving assembly, and the driving assembly is in transmission connection with the sample table and used for driving the sample table to rotate around the z axis of a three-dimensional coordinate system in the x-y plane of the three-dimensional coordinate system; the one-dimensional linear conveying rods are in sealing fit with the ultra-vacuum cavity, the working end of at least one one-dimensional linear conveying rod is arranged in the ultra-vacuum cavity, the working end of each one-dimensional linear conveying rod can fix a viscous material, the working end of each one-dimensional linear conveying rod points to the sample table, and in addition, the working end of each one-dimensional linear conveying rod is arranged in the sample table. And the working end of the at least one-dimensional linear transmission rod can move along the z axis of the three-dimensional coordinate system. According to the utility model, the in-situ cleavage and controllable stacking of the two-dimensional material in the ultrahigh vacuum environment can be realized, and by combining with the ultrahigh vacuum high-resolution characterization technology, the sample stacking angle is accurately controlled, meanwhile, the pollution of the sample in the atmospheric environment is avoided, and the cleanliness of the surface of the sample is ensured.

Description

Technical Field

[0001] The utility model particularly relates to a device capable of realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment, and belongs to the technical field of two-dimensional material cleavage. Background Art

[0002] The first discovery of graphene has opened up the exploration and research of atomically thin two-dimensional materials. With their rich electronic structures and excellent performance, two-dimensional materials have shown broad application prospects in electronic devices, photoelectrocatalysis, and energy storage. Two-dimensional materials provide an excellent platform for creating heterostructures with multiple properties. When two or more two-dimensional materials are stacked at a certain angle, many novel heterostructures can be formed due to the action of van der Waals forces. Two-dimensional heterojunctions do not rely on chemical bonds or are not limited by lattice matching. They can flexibly stack and assemble multiple materials together and are considered to be the most promising materials for exploring novel physical phenomena and realizing multifunctional devices. However, it is still very difficult to prepare two-dimensional materials with highly clean surfaces and two-dimensional heterojunctions with atomically smooth and clean interfaces, especially for surface-sensitive two-dimensional materials.

[0003] At present, the cleavage of two-dimensional materials is usually completed by mechanical cleavage in an atmospheric environment. Mechanical cleavage has the advantages of simple preparation process, strong flexibility, and high sample quality, which has made it a great success in the research of two-dimensional materials and has been widely used in the preparation process of heterojunction materials. However, this method also has many shortcomings: (1) Environmental pollution will introduce a large number of impurities or defects. Even for two-dimensional materials with stable surfaces, after the samples prepared by this method are introduced into the vacuum, due to the adsorption of a large number of molecules on the surface, it is difficult to measure them using surface-sensitive techniques such as scanning tunneling microscopy (STM) and angle-resolved photoelectron spectroscopy (ARPES) without annealing. High-temperature annealing may introduce more impurities or defects. (2) Many single crystal surfaces cannot exist stably in an atmospheric environment or even a low vacuum environment. This method will inevitably cause the sample surface to oxidize and adsorb a large number of impurities. Therefore, this method cannot prepare heterostructures constructed by two-dimensional materials and such substrates. (3) The stacking angle of heterojunction materials prepared in an atmospheric environment is often uncontrollable. Even if the stacking angle is effectively controlled by a special device, the angle is still very different from the actual angle, and high-resolution characterization in an ultra-high vacuum environment is still required to further confirm the true angle.

[0004] In addition, cleaving two-dimensional materials in an ultra-high vacuum environment mainly involves mounting the sample on a sample holder through a special instrument and cutting it with a knife parallel to the sample surface in an ultra-high vacuum chamber. This cleavage method avoids the introduction of impurities or defects in the atmospheric environment, but does not have the ability of controlled stacking. Utility Model Content

[0005] The main purpose of the utility model is to provide a device that can achieve precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment. While avoiding surface contamination of the two-dimensional materials, the device can simultaneously achieve two-dimensional material cleavage and controllable stacking in an ultra-high vacuum environment. In addition, when used in conjunction with ultra-high vacuum high-resolution characterization technology, the stacking angle of the two-dimensional material can be precisely controlled, thereby overcoming the shortcomings of the prior art.

[0006] In order to achieve the above-mentioned utility model purpose, the technical solution adopted by the utility model includes:

[0007] The first aspect of the utility model provides a device capable of realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment, comprising: an ultra-vacuum chamber one-dimensional linear transmission rod and a rotatable sample holder,

[0008] The rotatable sample holder is arranged in an ultra-vacuum chamber, and comprises a sample stage and a driving assembly, wherein the sample stage is used to carry a two-dimensional material, and the driving assembly is connected to the sample stage in a transmission manner and is used to drive the sample stage to rotate around the z-axis of a three-dimensional coordinate system in an xy plane of the three-dimensional coordinate system;

[0009] The one-dimensional linear transmission rod is sealed with the ultra-vacuum chamber, at least the working end of the one-dimensional linear transmission rod is arranged inside the ultra-vacuum chamber, the working end of the one-dimensional linear transmission rod can fix the viscous material, the working end of the one-dimensional linear transmission rod points to the sample stage, and at least the working end of the one-dimensional linear transmission rod can move along the z-axis of the three-dimensional coordinate system.

[0010] The second aspect of the utility model provides a method for cleaving and controllably stacking two-dimensional materials in an ultra-high vacuum environment, comprising:

[0011] Provide a device capable of achieving precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment;

[0012] forming an ultra-vacuum environment in the ultra-vacuum chamber, fixing the two-dimensional material on the sample stage, and repeatedly performing the following steps S1 and S2, thereby completing controllable stacking of the two-dimensional material;

[0013] S1: at least move the working end of the one-dimensional linear transmission rod closer to the sample stage along the z-axis until it is in close contact with the surface of the two-dimensional material in the first area of ​​the sample stage, and then move the working end of the one-dimensional linear transmission rod away from the sample stage along the z-axis, thereby completing the mechanical cleavage of the two-dimensional material;

[0014] S2 uses the driving component to drive the sample stage to rotate a specified angle around the z-axis, and again makes the working end of the one-dimensional linear transmission rod approach the sample stage along the z-axis until it is in close contact with the second area of ​​the sample stage or the surface of the two-dimensional material in the second area of ​​the sample stage.

[0015] Compared with the prior art, the advantages of the present invention include: an embodiment of the present invention provides a device that can realize precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment, and adopts a piezoelectric ceramic group to realize controllable rotation of two-dimensional materials in an ultra-high vacuum environment, and by controlling the voltage applied to the piezoelectric ceramic group, the rotation angle can be precisely controlled; and, the rotatable sample holder and the one-dimensional linear transmission rod can realize in-situ cleavage and controllable stacking of two-dimensional materials in an ultra-high vacuum environment, and all operations are completed in an ultra-high vacuum environment, avoiding contamination of the sample in the atmospheric environment and ensuring the cleanliness of the sample surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of a device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment, provided in a typical implementation case of the utility model;

[0017] Figure 2 It is a structural schematic diagram of a one-dimensional linear transmission rod in a typical implementation case of the utility model;

[0018] Figure 3a and Figure 3b All of them are structural schematic diagrams of a rotatable sample holder in a typical implementation case of the utility model;

[0019] Figure 4 It is a structural schematic diagram of a single piezoelectric ceramic group in a typical implementation case of the utility model;

[0020] Figure 5a It is a structural schematic diagram of a base in a rotatable sample holder in a typical implementation case of the utility model;

[0021] Figure 5b It is a partial structural schematic diagram of a rotatable sample holder in a typical implementation case of the utility model;

[0022] Figure 6a It is a partial structural schematic diagram of a rotatable sample holder in a typical implementation case of the utility model;

[0023] Figure 6b It is a structural schematic diagram of a rotatable sample holder in a typical implementation case of the utility model;

[0024] Figure 7 It is a structural schematic diagram of a sample stage in a typical implementation case of the utility model. DETAILED DESCRIPTION

[0025] In view of the deficiencies in the prior art, the inventor of this case has proposed the technical solution of the utility model after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.

[0026] The first aspect of the utility model provides a device capable of realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment, comprising: an ultra-vacuum chamber one-dimensional linear transmission rod and a rotatable sample holder,

[0027] The rotatable sample holder is arranged in an ultra-vacuum chamber, and comprises a sample stage and a driving assembly, wherein the sample stage is used to carry a two-dimensional material, and the driving assembly is connected to the sample stage in a transmission manner and is used to drive the sample stage to rotate around the z-axis of a three-dimensional coordinate system in an xy plane of the three-dimensional coordinate system;

[0028] The one-dimensional linear transmission rod is sealed with the ultra-vacuum chamber, at least the working end of the one-dimensional linear transmission rod is arranged inside the ultra-vacuum chamber, the working end of the one-dimensional linear transmission rod can fix the viscous material, the working end of the one-dimensional linear transmission rod points to the sample stage, and at least the working end of the one-dimensional linear transmission rod can move along the z-axis of the three-dimensional coordinate system.

[0029] Furthermore, the driving assembly includes a piezoelectric ceramic group, and the rotation angle of the sample stage corresponds to the bias voltage applied to the piezoelectric ceramic group.

[0030] Furthermore, the rotatable sample holder also includes a base, the piezoelectric ceramic group is fixedly arranged on the base, the sample table is arranged on the piezoelectric ceramic group and is in active contact with the top surface of the piezoelectric ceramic group, and the base is also provided with an external electrode, the piezoelectric ceramic group is electrically connected to the external electrode, and the external electrode is used to be electrically connected to a power supply.

[0031] Furthermore, the driving component includes a plurality of piezoelectric ceramic groups, the plurality of piezoelectric ceramic groups are arranged at circumferential intervals along the sample stage, the sample stage is arranged on the plurality of piezoelectric ceramic groups along the z-axis direction and is in active contact with the top end surfaces of the plurality of piezoelectric ceramic groups, and the base is provided with a plurality of external electrodes, and the plurality of piezoelectric ceramic groups are electrically connected to the plurality of external electrodes respectively.

[0032] Furthermore, the piezoelectric ceramic group includes multiple piezoelectric ceramic sheet assemblies, each of which includes a piezoelectric ceramic sheet and an upper electrode and a lower electrode electrically connected to the piezoelectric ceramic sheet. The piezoelectric ceramic is stacked between the upper electrode and the lower electrode along the z-axis direction, and multiple piezoelectric ceramic sheet assemblies are connected in series.

[0033] Furthermore, the plurality of piezoelectric ceramic sheet assemblies are stacked in sequence along the z-axis direction, the upper electrode in the piezoelectric ceramic sheet assembly is arranged above the piezoelectric ceramic sheet along the z-axis direction, and the lower electrode is arranged below the piezoelectric ceramic sheet along the z-axis direction, and the piezoelectric ceramic group also includes a plurality of insulating isolation pads, and the plurality of isolation pads are respectively arranged between two adjacent piezoelectric ceramic sheet assemblies and between the piezoelectric ceramic sheet assembly and the base, and between the piezoelectric ceramic sheet assembly and the sample stage. An upper electrode and a lower electrode of two adjacent piezoelectric ceramic sheet assemblies are electrically isolated by the isolation pad located between the two piezoelectric ceramic sheet assemblies, and the piezoelectric ceramic sheet assembly is also electrically isolated from the sample stage and the base by the isolation pad.

[0034] Furthermore, the isolation pad between two adjacent piezoelectric ceramic sheet assemblies is arranged between an upper electrode and a lower electrode of the two piezoelectric ceramic sheet assemblies.

[0035] Furthermore, the relative position relationship between the upper electrode, the lower electrode and the piezoelectric ceramic sheet in any two of the piezoelectric ceramic groups is the same.

[0036] Furthermore, the base is provided with a plurality of first positioning grooves, and the bottom of each of the piezoelectric ceramic groups is correspondingly arranged in one of the first positioning grooves.

[0037] In a more specific embodiment, the sample stage is a ferromagnet or a ferromagnet is arranged in the sample stage, and the rotatable sample holder also includes a magnet, and the magnet is fixedly arranged on the base, and the magnet is magnetically adsorbed to the sample stage or the ferromagnet in the sample stage, and the magnetic adsorption force between the magnet and the sample stage or the ferromagnet in the sample stage ensures that the sample stage always maintains contact with the top surface of the piezoelectric ceramic group.

[0038] Furthermore, the rotatable sample holder includes a plurality of magnets, and the plurality of magnets and the plurality of piezoelectric ceramic groups are alternately arranged in sequence along the circumference of the sample stage.

[0039] Furthermore, in the z-axis direction, the position of the top surface of the piezoelectric ceramic group is higher than the position of the top surface of the magnet.

[0040] Furthermore, the magnet and the sample stage are clearance-fitted.

[0041] Furthermore, the base is provided with a plurality of second positioning grooves, and the bottom of each of the magnets is correspondingly arranged in one of the second positioning grooves.

[0042] In a more specific embodiment, the device that can achieve precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment also includes: a limiting structure, which is fixedly arranged on the base, and is used to limit the translational movement of the sample stage along its own radial direction and limit the separation of the sample stage from the piezoelectric ceramic group.

[0043] Furthermore, the sample stage has a limiting hole that penetrates along its own axial direction, and the limiting structure includes a first limiting mechanism, the first limiting mechanism is fixed on the base, and the axial direction of the first limiting mechanism is parallel to the z-axis, the first limiting mechanism is partially arranged in the limiting hole, the first limiting mechanism and the limiting hole are gap-matched, and in the z-axis direction, the position of the top end surface of the first limiting mechanism is lower than the position of the table top of the sample stage for supporting the two-dimensional material.

[0044] Furthermore, the limiting structure includes a plurality of second limiting mechanisms, which are fixedly arranged on the base and spaced apart along the circumference of the sample stage, and the second limiting mechanism has a first limiting portion and a second limiting portion, the first limiting portion is arranged on the outer side of the sample stage along the radial direction of the sample stage, the second limiting portion is arranged above the sample stage along the axial direction of the sample stage, and the second limiting portion has no direct contact with the sample stage.

[0045] Furthermore, the one-dimensional linear transmission rod is movably coordinated with the ultra-vacuum chamber, and the one-dimensional linear transmission rod as a whole can move linearly along the z-axis.

[0046] The second aspect of the utility model provides a method for cleaving and controllable stacking of two-dimensional materials in an ultra-high vacuum environment, comprising:

[0047] Provide a device capable of achieving precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment;

[0048] forming an ultra-vacuum environment in the ultra-vacuum chamber, fixing the two-dimensional material on the sample stage, and repeatedly performing the following steps S1 and S2, thereby completing controllable stacking of the two-dimensional material;

[0049] S1: at least move the working end of the one-dimensional linear transmission rod closer to the sample stage along the z-axis until it is in close contact with the surface of the two-dimensional material in the first area of ​​the sample stage, and then move the working end of the one-dimensional linear transmission rod away from the sample stage along the z-axis, thereby completing the mechanical cleavage of the two-dimensional material;

[0050] S2 uses the driving component to drive the sample stage to rotate a specified angle around the z-axis, and again makes the working end of the one-dimensional linear transmission rod approach the sample stage along the z-axis until it is in close contact with the second area of ​​the sample stage or the surface of the two-dimensional material in the second area of ​​the sample stage.

[0051] In a more specific embodiment, the method for cleaving and controllable stacking of two-dimensional materials in an ultra-high vacuum environment further includes:

[0052] S3 uses in-situ scanning tunneling microscopy in an ultra-high vacuum environment to obtain atomic-level resolution images of the stacking area on the sample surface. The actual stacking angle is calculated based on the period of the moiré structure formed in the stacking area, which is used to calibrate the bias voltage applied by the drive component to accurately control the stacking angle of the two-dimensional material.

[0053] The technical solution, its implementation process and principle will be further explained below in conjunction with the accompanying drawings.

[0054] See also Figure 1-Figure 7 In order to realize the cleavage and controllable stacking of two-dimensional materials in an ultra-high vacuum environment, an embodiment of the utility model provides a device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment, which includes two parts: a one-dimensional linear transmission rod 100 and a rotatable sample holder, the rotatable sample holder is arranged in an ultra-vacuum chamber, the rotatable sample holder includes a sample table 200 and a driving component 300, the sample table 200 is used to carry the two-dimensional material, the driving component 300 is transmission-connected to the sample table 200, the sample table 200 can only rotate around its own central axis in the xy surface of a three-dimensional coordinate system, the one-dimensional linear transmission rod 100 is movable and sealed with the ultra-vacuum chamber, the center of the one-dimensional linear transmission rod 100 is aligned with the center of the sample table 200 of the rotatable sample holder, the one-dimensional linear transmission rod 100 can only move along the z-axis of the three-dimensional coordinate system, and the central axis of the sample table 200 is parallel to or coincides with the z-axis.

[0055] Figure 1 The overall picture of the one-dimensional linear transmission rod is as follows Figure 2As shown, the front end of the one-dimensional linear transmission rod 100 serves as a working end, and the one-dimensional linear transmission rod 100 can fix viscous materials. Specifically, the one-dimensional linear transmission rod 100 can be installed on an ultra-high vacuum chamber through a flange plate and the like and can be movably and sealedly matched with the ultra-vacuum chamber. The specific structure for realizing the movement and sealing of the one-dimensional linear transmission rod 100 and the ultra-vacuum chamber is known to those skilled in the art and will not be described in detail here. More specifically, the working end of the one-dimensional linear transmission rod 100 is directly opposite to the center position of the sample stage 200 of the rotatable sample holder, and the working end of the front end of the one-dimensional linear transmission rod 100 fixes the viscous material. By moving the one-dimensional linear transmission rod 100 and bringing it close to and then away from the two-dimensional material on the sample stage, the mechanical cleavage of the two-dimensional material can be achieved. By bringing the one-dimensional linear transmission rod 100 with the two-dimensional material stuck to it close to the sample stage 200 again, the controllable stacking of the two-dimensional material can be completed under the action of the van der Waals force.

[0056] Figure 1 The overall view of the rotatable sample holder in Figure 3a and Figure 3b As shown, the rotatable sample holder also includes a base 400, the driving assembly 300 includes a plurality of piezoelectric ceramic groups 310, the plurality of piezoelectric ceramic groups 310 are fixedly mounted on the base 400, the sample stage 200 is arranged on the top surfaces of the plurality of piezoelectric ceramic groups 310 along the z-axis and is in active contact with the top surfaces of the plurality of piezoelectric ceramic groups 310, and the sample stage 200 rotates in situ driven by the plurality of piezoelectric ceramic groups 310. It can be understood that the piezoelectric ceramic groups 310 not only serve as a power source for driving the sample stage 200 to rotate, but the plurality of piezoelectric ceramic groups 310 also serve as a supporting structure for supporting the sample stage 200.

[0057] Specifically, the plurality of piezoelectric ceramic groups 310 are fixed on the base 400 at intervals in sequence along the circumferential direction of the sample stage 200 . Figure 3a and Figure 3b It is shown that three piezoelectric ceramic groups 310 are used as driving components for driving the sample stage 200. Four independent external electrodes 500 are arranged on the base 400. The external electrodes 500 can be connected to the electrodes of the piezoelectric ceramic group 310 (i.e., the upper electrode and the lower electrode hereinafter) by using enameled wire (to avoid contact with other parts of the rotatable sample holder) to apply bias to the piezoelectric ceramic group 310 in situ. By controlling the magnitude of the applied voltage, the rotation angle of the sample stage can be precisely controlled.

[0058] Figure 4The figure is a schematic diagram of the structure of the piezoelectric ceramic group. In order to realize a large range of rotation of the sample, each piezoelectric ceramic group 310 includes a plurality of piezoelectric ceramic sheet assemblies stacked and connected in series along the z-axis. Each piezoelectric ceramic sheet assembly includes a piezoelectric ceramic sheet 311 and an upper electrode 312 and a lower electrode 313. The piezoelectric ceramic sheet 311 is arranged between the upper electrode 312 and the lower electrode 313 along the z-axis. The upper and lower ends of the piezoelectric ceramic sheet 311 are electrically connected to the upper electrode 312 and the lower electrode 313 respectively. The metal electrodes between the plurality of piezoelectric ceramic sheet assemblies (the upper electrode 312 of one piezoelectric ceramic sheet assembly and the lower electrode 313 of another piezoelectric ceramic sheet assembly) are isolated by an insulating isolation pad 314. At the same time, thicker insulating isolation pads 314 are also arranged at the upper and lower ends of each piezoelectric ceramic group 310. The piezoelectric ceramic group 310 is electrically isolated from the sample stage 200 and the base 400 via the isolation pads 314 located at the upper and lower ends respectively.

[0059] For details, please refer to Figure 4 A portion of the upper electrode 312 included in each piezoelectric ceramic sheet component is arranged at the upper end of the piezoelectric ceramic sheet 31.1, and another portion is arranged at the first side of the piezoelectric ceramic sheet 311; a portion of the lower electrode 313 is arranged at the lower end of the piezoelectric ceramic sheet 311, and another portion is arranged at the second side of the piezoelectric ceramic sheet 311; a plurality of upper electrodes 312 of a plurality of piezoelectric ceramic sheet components included in each piezoelectric ceramic group 310 are located on the same side and are electrically connected; a plurality of lower electrodes 313 are located on the same side and are electrically connected, that is, a plurality of piezoelectric ceramic sheet components included in each piezoelectric ceramic group 310 are connected in series; Figure 4 The figure shows three piezoelectric ceramic plates connected in series and working together.

[0060] For details, please refer to Figure 5a and Figure 5b , a plurality of magnets 700 are also arranged on the base 400, the sample stage 200 is a ferromagnet or a ferromagnet is arranged inside the sample stage 200, and the sample stage 200 maintains contact with the top surface of the piezoelectric ceramic group 310 through the magnetic adsorption force of the three or more magnets 700 below the sample stage 200. More specifically, the plurality of magnets 700 are arranged in sequence along the circumference of the sample stage 200. More specifically, the plurality of magnets 700 and the plurality of piezoelectric ceramic groups 310 are arranged alternately at intervals, and the height of the top surface of the magnet 700 is lower than the height of the top surface of the piezoelectric ceramic group 310, and the magnet 700 does not directly contact the sample stage 200 to ensure the rotation of the sample and the sample stage above it.

[0061] More specifically, the base 400 is further provided with a plurality of first positioning grooves 410, and the bottom of each of the piezoelectric ceramic groups 310 is correspondingly arranged in one of the first positioning grooves 410. The base 400 is further provided with a plurality of second positioning grooves 420, and the bottom of each of the magnets 700 is correspondingly arranged in one of the second positioning grooves 420. More specifically, the piezoelectric ceramic group 310 can be fixed on the base 400 by insulating glue. During the installation process, attention should be paid to the electrode polarity of the piezoelectric ceramic sheet assembly included in the piezoelectric ceramic group 310, and the upper electrode and the lower electrode should be kept in the same direction, for example, arranged clockwise or counterclockwise ( Figure 5b More specifically, the magnet 700 can also be fixed on the base 400 by insulating glue. Exemplarily, the magnet can be a cylindrical magnet.

[0062] For details, please refer to Figure 1 A plurality of limiting structures 600 are also provided on the base 400, and the limiting structures 600 are used to limit the translational movement of the sample stage along its own radial direction and to limit the separation of the sample stage from the piezoelectric ceramic group, that is, the sample stage 200 can only rotate in the xy plane.

[0063] For details, please refer to Figure 6a , Figure 6b as well as Figure 7 The central area of ​​the sample stage 200 has a limiting hole 201 that penetrates along its own axial direction. The limiting structure includes a first limiting mechanism 610 and a plurality of second limiting mechanisms 620. The first limiting mechanism 610 and the plurality of second limiting mechanisms 620 are fixed on the base 400. The plurality of second limiting mechanisms 620 are arranged at intervals along the circumference of the sample stage 200 and are distributed around the periphery of the first limiting mechanism 610. More specifically, the plurality of second limiting mechanisms 620 are distributed around the periphery of the plurality of magnets 700 and the plurality of piezoelectric ceramic groups 310. Specifically, the axial direction of the first limiting mechanism 610 is parallel to the z-axis, a part of the first limiting mechanism 610 is arranged in the limiting hole, the first limiting mechanism 610 is in clearance with the limiting hole, and in the z-axis direction, the position of the top surface of the first limiting mechanism 610 is lower than the position of the table surface at the top of the sample stage 200 for carrying the two-dimensional material. Specifically, the second limiting mechanism 620 has a first limiting portion 621 and a second limiting portion 622. The first limiting portion 621 is arranged on the outside of the sample stage 200 along the radial direction of the sample stage, and the second limiting portion 622 is arranged above the sample stage 200 along the axial direction of the sample stage. Moreover, the second limiting portion 622 has no direct contact with the sample stage 200. Exemplarily, the first limiting mechanism 610 can be a limiting column, etc.

[0064] Specifically, the first limiting mechanism 610 can ensure that the sample stage 200 can only rotate around the z-axis without radial movement, and the limiting devices around it do not directly contact the sample stage. Specifically, the second limiting mechanism 620 keeps a distance of about 1mm from the side and top surfaces of the sample stage 200, and the sample stage is fixed by the magnetic force of the magnet. The function of the second limiting mechanisms 620 around it is to assist the installation of the sample stage and prevent the sample stage from detaching in an accident.

[0065] For details, please refer to Figure 7 The sample stage 200 can be an annular structure as a whole. Specifically, the sample stage 200 includes an annular metal component 210 and an annular sapphire component 220. The back of the annular metal component 210 and the sapphire component 220 are connected by insulating glue. The sapphire component 220 is in direct contact with the top surface of the piezoelectric ceramic group to reduce friction and wear during the rotation of the sample stage. A square limiting groove 211 is opened on the surface of the annular metal component 210. The limiting groove 211 is used to fix the sample. The sample is connected to the metal component 210 by conductive glue.

[0066] Specifically, the sapphire component 220 at the bottom of the sample stage is in contact with the top of the piezoelectric ceramic group 310, the bottom of the sample stage 200 is not in contact with the top of the magnet 700, the center hole 201 of the sample stage 200 is in coaxial contact with the vertical first limiting mechanism 610 without force, and the top of the sample stage 200 is not in contact with the second limiting part 622 of the second limiting mechanism 620 at the upper end, and a distance of about 1 mm is retained. The external electrode 500 on the base 400 is in contact with the electrode of the piezoelectric ceramic group 310, but is insulated from the two-dimensional material on the sample stage 200 and the rotatable sample holder. The external electrode on the base can be in direct contact with the electrode in the ultra-high vacuum cavity, so as to realize direct voltage application from the outside of the cavity.

[0067] Specifically, a device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment provided by the embodiment of the utility model is used to complete the cleavage and controllable stacking operation of two-dimensional materials in an ultra-high vacuum chamber. The specific operation is as follows: fix the two-dimensional material on the sample stage of the rotatable sample holder, make the one-dimensional linear transmission rod approach the two-dimensional material along the z-axis direction until it is close to the surface of the two-dimensional material, and complete the mechanical cleavage of the two-dimensional material, and then apply a specific bias voltage to the piezoelectric ceramic group on the rotatable sample holder to complete the rotation of the sample stage at a specified angle, and again make the one-dimensional linear transmission rod approach the two-dimensional material along the z-axis direction until it is close to the surface of the two-dimensional material, thereby completing the controllable stacking of the two-dimensional material, and finally, with the help of an optical microscope, select a suitable sample area, and then use scanning tunneling microscopy (STM), angle-resolved photoelectron spectroscopy (ARPES) and other surface-sensitive technologies to characterize the homojunction angle-rotated two-dimensional materials. If the two-dimensional material is replaced after the mechanical cleavage of the two-dimensional material is completed, the preparation and characterization of the heterojunction angle-rotated sample can be achieved.

[0068] The embodiment of the utility model provides a device that can realize precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment. A piezoelectric ceramic group is used to realize controllable rotation of the two-dimensional material in an ultra-high vacuum environment, and the rotation angle can be precisely regulated by controlling the voltage applied to the piezoelectric ceramic group. In addition, a rotatable sample holder and a one-dimensional linear transmission rod can realize in-situ cleavage and controllable stacking of two-dimensional materials in an ultra-high vacuum environment. All operations are completed in an ultra-high vacuum environment, avoiding contamination of the sample in the atmospheric environment and ensuring the cleanliness of the sample surface.

[0069] It should be understood that the above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A device capable of realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment, characterized in that: include: Ultra-vacuum chamber one-dimensional linear transmission rod, rotatable sample holder, The rotatable sample holder is arranged in an ultra-vacuum chamber, and comprises a sample stage and a driving assembly, wherein the sample stage is used to carry a two-dimensional material, and the driving assembly is connected to the sample stage in a transmission manner and is used to drive the sample stage to rotate around the z-axis of a three-dimensional coordinate system in an xy plane of the three-dimensional coordinate system; The one-dimensional linear transmission rod is sealed with the ultra-vacuum chamber, at least the working end of the one-dimensional linear transmission rod is arranged inside the ultra-vacuum chamber, the working end of the one-dimensional linear transmission rod can fix the viscous material, the working end of the one-dimensional linear transmission rod points to the sample stage, and at least the working end of the one-dimensional linear transmission rod can move along the z-axis of the three-dimensional coordinate system.

2. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 1, characterized in that: The driving assembly includes a piezoelectric ceramic group, and the rotation angle of the sample stage corresponds to the bias voltage applied to the piezoelectric ceramic group.

3. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 2, characterized in that: The rotatable sample holder also includes a base, the piezoelectric ceramic group is fixedly arranged on the base, the sample stage is arranged on the piezoelectric ceramic group and is in active contact with the top surface of the piezoelectric ceramic group, and the base is also provided with an external electrode, the piezoelectric ceramic group is electrically connected to the external electrode, and the external electrode is used to be electrically connected to a power supply.

4. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 3, characterized in that: The driving component includes a plurality of piezoelectric ceramic groups, the plurality of piezoelectric ceramic groups are arranged at intervals along the circumference of the sample stage, the sample stage is arranged on the plurality of piezoelectric ceramic groups along the z-axis direction and is in active contact with the top surfaces of the plurality of piezoelectric ceramic groups, and the base is provided with a plurality of external electrodes, and the plurality of piezoelectric ceramic groups are electrically connected to the plurality of external electrodes respectively.

5. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 3 or 4, characterized in that: The piezoelectric ceramic group includes a plurality of piezoelectric ceramic sheet assemblies, each of which includes a piezoelectric ceramic sheet and an upper electrode and a lower electrode electrically connected to the piezoelectric ceramic sheet. The piezoelectric ceramic is stacked between the upper electrode and the lower electrode along the z-axis direction, and a plurality of the piezoelectric ceramic sheet assemblies are connected in series.

6. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 5, characterized in that: The plurality of piezoelectric ceramic sheet assemblies are stacked in sequence along the z-axis direction, the upper electrode in the piezoelectric ceramic sheet assembly is arranged above the piezoelectric ceramic sheet along the z-axis direction, and the lower electrode is arranged below the piezoelectric ceramic sheet along the z-axis direction, and the piezoelectric ceramic group also includes a plurality of insulating isolation pads, which are respectively arranged between two adjacent piezoelectric ceramic sheet assemblies, between the piezoelectric ceramic sheet assembly and the base, and between the piezoelectric ceramic sheet assembly and the sample stage. An upper electrode and a lower electrode of two adjacent piezoelectric ceramic sheet assemblies are electrically isolated via the isolation pad located between the two piezoelectric ceramic sheet assemblies, and the piezoelectric ceramic sheet assembly is also electrically isolated from the sample stage and the base via the isolation pad.

7. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 6, characterized in that: The isolation pad between two adjacent piezoelectric ceramic sheet assemblies is arranged between an upper electrode and a lower electrode of the two piezoelectric ceramic sheet assemblies.

8. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 7, characterized in that: The relative position relationship between the upper electrode, the lower electrode and the piezoelectric ceramic sheet in any two of the piezoelectric ceramic groups is the same.

9. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 6, characterized in that: The base is also provided with a plurality of first positioning grooves, and the bottom of each of the piezoelectric ceramic groups is correspondingly arranged in one of the first positioning grooves.

10. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 4, characterized in that: The sample stage is a ferromagnet or a ferromagnet is arranged in the sample stage, and the rotatable sample holder also includes a magnet, and the magnet is fixedly arranged on the base. The magnet is magnetically attracted to the sample stage or the ferromagnet in the sample stage, and the magnetic attraction force between the magnet and the sample stage or the ferromagnet in the sample stage ensures that the sample stage always maintains contact with the top surface of the piezoelectric ceramic group.

11. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 10, characterized in that: The rotatable sample holder comprises a plurality of magnets, and the plurality of magnets and the plurality of piezoelectric ceramic groups are alternately arranged in sequence along the circumference of the sample stage.

12. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 10, characterized in that: In the z-axis direction, the position of the top end surface of the piezoelectric ceramic group is higher than the position of the top end surface of the magnet.

13. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 10, characterized in that: The magnet and the sample stage are clearance-fitted.

14. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 10, characterized in that: The base is also provided with a plurality of second positioning grooves, and the bottom of each of the magnets is correspondingly arranged in one of the second positioning grooves.

15. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 4, characterized in that: Also includes: A limiting structure, wherein the limiting structure is fixedly arranged on the base, and the limiting structure is used to limit the translational movement of the sample stage along its own radial direction and to limit the separation of the sample stage from the piezoelectric ceramic group.

16. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 15, characterized in that: The sample stage has a limiting hole that penetrates along its own axial direction, and the limiting structure includes a first limiting mechanism, the first limiting mechanism is fixed on the base, and the axial direction of the first limiting mechanism is parallel to the z-axis, the first limiting mechanism is partially arranged in the limiting hole, the first limiting mechanism and the limiting hole are gap-matched, and in the z-axis direction, the position of the top end surface of the first limiting mechanism is lower than the position of the table top of the sample stage for supporting the two-dimensional material.

17. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 16, characterized in that: The limiting structure includes a plurality of second limiting mechanisms, which are fixedly arranged on the base and spaced apart along the circumference of the sample stage, and the second limiting mechanism has a first limiting portion and a second limiting portion, the first limiting portion is arranged on the outer side of the sample stage along the radial direction of the sample stage, the second limiting portion is arranged above the sample stage along the axial direction of the sample stage, and the second limiting portion has no direct contact with the sample stage.

18. The device for realizing precise control of the stacking angle of two-dimensional materials in an ultra-high vacuum environment according to claim 1, characterized in that: The one-dimensional linear transmission rod is movably matched with the ultra-vacuum chamber, and the one-dimensional linear transmission rod as a whole can move linearly along the z-axis.

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