Electro-actuated devices for ultra-lubricated interface sliding, microelectromechanical system (MEMS) drive devices, MEMS and electro-actuated sliding methods

Abstract

This application discloses an electro-actuated device for superlubricated interface sliding, a microelectromechanical system (MEMS) drive device, a MEMS, and an electro-actuated sliding method, belonging to the field of MEMS technology. The electro-actuated device for superlubricated interface sliding provided by this invention includes a superlubricated van der Waals heterojunction, a first metal electrode, and a second metal electrode. The superlubricated van der Waals heterojunction includes a two-dimensional material platform with a conductive two-dimensional material layer on its surface, and a movable two-dimensional material stacked on the surface of the two-dimensional material platform. The lattice constant of the conductive two-dimensional material layer differs from that of the movable two-dimensional material by more than 1.8%. The electro-actuated device for superlubricated interface sliding provided by this invention can achieve nanoscale movement, and the frictional force during electro-actuated sliding is close to zero, effectively improving the sensitivity, accuracy, and service life of the MEMS drive device and MEMS based on it.

Description

Technical Field

[0001] This invention belongs to the field of microelectromechanical systems (MEMS) technology, and particularly relates to an electro-drive device for ultra-lubricated interface sliding, a MEMS drive device, a MEMS, and an electro-drive sliding method. Background Technology

[0002] Micro-Electro-Mechanical Systems (MEMS) are miniature systems fabricated using microfabrication techniques (such as photolithography, etching, and thin-film deposition). They are composed of micromechanical structures (such as cantilever beams, diaphragms, and gears), electronic components (such as electrodes and transistors), and functional parts (such as sensors and actuators). MEMS can sense, control, or drive physical quantities (such as force, displacement, and temperature), chemical quantities (such as gas concentration), or biological quantities (such as biomolecules), and transmit and process information through electrical signals. They are widely used in sensors, actuators, and other intelligent devices. Numerous material systems are suitable for MEMS, including polymers, metals, ceramics, silicon-based materials, and composite materials. These materials are widely used in different types of MEMS devices based on their properties and application requirements, with silicon-based materials currently being the mainstream material.

[0003] Silicon-based microelectromechanical systems (MEMS) devices typically have micrometer-scale dimensions, enabling them to operate in space-constrained environments. Due to their tiny mass and low inertia, silicon-based MEMS devices achieve rapid dynamic responses. Furthermore, silicon-based MEMS can be highly integrated with other electronic components, enabling functional integration. Silicon-based MEMS can measure displacement changes at the micrometer or even sub-micrometer scale. However, some properties of silicon also hinder the further expansion of its applications. For example, silicon is relatively brittle and prone to fracture upon impact; its high density also limits design flexibility. For example, in high-sensitivity sensors requiring low stiffness, silicon's high stiffness limits detection accuracy; in the field of MEMS actuators for micro-aircraft applications demanding lightweight design, silicon-based structures increase overall weight due to their high density; furthermore, silicon itself is not piezoelectric, non-magnetostrictive, or thermoelectric, and cannot directly achieve energy conversion such as "electromechanical" or "magnetic-mechanical" conversions, requiring integration with external functional materials. This introduces additional challenges: if actuation functions (such as micro-valve opening and closing) are needed, piezoelectric materials (such as AlN or PZT thin films) must be integrated, but the coefficient of thermal expansion of silicon differs from that of piezoelectric materials (silicon: 2.6 × 10⁻⁶). -6 / ℃;PZT:8×10 -6A mismatch in temperature (°C / ℃) can generate interfacial stress during temperature changes, leading to film cracking or performance drift. Furthermore, movable structures in silicon-based MEMS, such as gears and micromirrors, typically require gaps of at least 1 μm; otherwise, they are prone to adhesion. Additionally, due to etching residues, the surface roughness (Ra) of silicon-based materials is usually greater than 10 nm, resulting in severe friction and wear. For example, the lifespan of silicon-based microgears is typically less than 1 × 10⁻⁶. 6 Rotation speed, far lower than 1×10⁻⁶ for macroscopic metal gears. 9 change.

[0004] Therefore, considering the current shortcomings of microelectromechanical systems (MEMS) technology, the various influences of market demand and changes in application fields, there is an urgent need to achieve development goals such as further miniaturization, weight reduction, and improvement of device sensitivity, accuracy, and lifespan.

[0005] Currently, significant progress has been made in the miniaturization and performance improvement of microelectromechanical systems (MEMS), including the introduction of nanomaterials and photosensitive materials during fabrication to enhance microstructure strength and processing precision, as well as optimizing structural design to improve sensitivity. However, these improvements still have limitations. Taking MEMS containing functionalized materials and optical silicon-based MEMS as examples: Functionalized material MEMS incorporate graphene as a reinforcing material, which limits miniaturization and involves multi-interface processing, making fabrication difficult. Optical silicon-based MEMS (mirrors or micromirror arrays) can control nanoscale optical path movement through micro-adjustments, but the process is complex, and direct high-precision actuation of structural components is not yet possible.

[0006] Two-dimensional materials possess unique layered structures and surface properties, among which the weak interactions between the layers enable them to achieve a superlubricated state. This "superlubricity" is due to incommensurate contact resulting in a friction coefficient as low as 10. -3 Even lower levels of friction loss are significant for reducing frictional losses and energy consumption, but research on their application in the field of microelectromechanical systems (MEMS) remains limited. Chinese patent application CN114873555A discloses a method and device for modulating frictional force between superlubricated interfaces. However, its essence lies in using an external Coulomb force to change the electrical state of the two-dimensional material surface, achieving electrostatic attraction or repulsion between the first and second superlubricated material layers to modulate frictional force. The device structure requires an external conductive and dielectric layer, making it complex, and additional mechanical force is still needed for operation.

[0007] Therefore, from the perspective of "small size and integration requirements", especially in order to realize the fabrication of nanoscale microelectromechanical systems and the driving of nanoscale structural components, developing a reliable, low-loss, and high-precision microelectromechanical system and driving method has become an urgent technical challenge for the development of new microelectromechanical systems. Summary of the Invention

[0008] The technical problem that the invention aims to solve:

[0009] To address the above problems, the present invention provides an electrically driven device for ultra-lubricating interface slippage, and an electrically driven slippage method based thereon. The electrically driven device for ultra-lubricating interface slippage can realize reliable transport of micro- and nano-materials with nanoscale precision.

[0010] Meanwhile, the present invention further provides a microelectromechanical system (MEMS) drive device containing an electro-drive device with super-lubricated interface slippage, as well as a MEMS.

[0011] Technical solution:

[0012] To achieve the above-mentioned objectives of the present invention, the embodiments of the present invention adopt the following technical solutions:

[0013] The first aspect of the present invention provides an electrically driven device for ultra-lubricated interface slippage, comprising:

[0014] Superlubricated van der Waals heterojunction;

[0015] The first metal electrode and the second metal electrode are connected to the superlubricated van der Waals heterojunction;

[0016] The superlubricated van der Waals heterojunction includes a two-dimensional material platform and a movable two-dimensional material stacked on the surface of the two-dimensional material platform.

[0017] The two-dimensional material platform includes a conductive two-dimensional material layer on its surface, and the movable two-dimensional material is stacked on the surface of the conductive two-dimensional material layer.

[0018] The surface roughness of the conductive two-dimensional material layer is less than 2 nm, and the lattice constant of the conductive two-dimensional material layer differs from that of the movable two-dimensional material (110) by more than 1.8%.

[0019] The first metal electrode and the second metal electrode are respectively connected to the conductive two-dimensional material layer.

[0020] It should be noted that when the first and second metal electrodes, as described above, are electrically connected to the external excitation power supply, a current density can be generated on the conductive two-dimensional material layer. Furthermore, by adjusting the input voltage of the external excitation power supply, the magnitude of the current density generated on the conductive two-dimensional material layer can be adjusted, thereby enabling the movable two-dimensional material to slide on the surface of the conductive two-dimensional material layer through electrical drive.

[0021] As a preferred embodiment of any technical solution in the first aspect of the present invention, the lattice constant of the conductive two-dimensional material layer differs from the lattice constant of the movable two-dimensional material by 2.0% to 400%.

[0022] More preferably, the lattice constant of the conductive two-dimensional material layer differs from the lattice constant of the movable two-dimensional material by 5.0% to 300%.

[0023] More preferably, the lattice constant of the conductive two-dimensional material layer differs from the lattice constant of the movable two-dimensional material by 10% to 200%.

[0024] As a preferred embodiment of any technical solution in the first aspect of the present invention, the size of the movable two-dimensional material is smaller than the size of the conductive two-dimensional material layer.

[0025] As a preferred embodiment of any technical solution in the first aspect of the present invention, the surface roughness of the conductive two-dimensional material layer is less than 2 nm.

[0026] More preferably, the surface roughness of the conductive two-dimensional material layer is less than 1 nm.

[0027] It should be noted that the surface roughness in this invention is measured in terms of the surface arithmetic mean roughness (Ra).

[0028] More preferably, the surface roughness of the conductive two-dimensional material layer is 0~2 nm.

[0029] More preferably, the surface roughness of the conductive two-dimensional material layer is 0~1nm.

[0030] As a preferred embodiment of any technical solution in the first aspect of the present invention, the thickness of the two-dimensional material platform is not less than 10 nm;

[0031] More preferably, the thickness of the two-dimensional material platform is 10~200 nm;

[0032] More preferably, the thickness of the two-dimensional material platform is 30.3~100.3 nm.

[0033] As a preferred embodiment of any technical solution in the first aspect of the present invention, the thickness of the conductive two-dimensional material layer is 0.3~100 nm.

[0034] More preferably, the thickness of the conductive two-dimensional material layer is 0.3~30 nm;

[0035] More preferably, the thickness of the conductive two-dimensional material layer is 0.3~9.7 nm.

[0036] As a preferred embodiment of any technical solution in the first aspect of the present invention, the movable two-dimensional material is selected from one or more of hexagonal boron nitride, graphene, and transition metal compounds.

[0037] As a preferred embodiment of any technical solution in the first aspect of the present invention, the material of the conductive two-dimensional material layer is selected from one or more of graphene and transition metal compounds.

[0038] As a preferred embodiment of any technical solution in the first aspect of the present invention, the movable two-dimensional material and the conductive two-dimensional material layer are made of different materials.

[0039] As a preferred embodiment of any technical solution in the first aspect of the present invention, the two-dimensional material platform further includes a transitional two-dimensional material layer, which is disposed below the conductive two-dimensional material layer.

[0040] As a preferred embodiment of any technical solution in the first aspect of the present invention, the material of the transition two-dimensional material layer includes one or more of hexagonal boron nitride, graphene, and transition metal compounds.

[0041] It should be noted that, due to the "miniaturization and integration requirements" of electrically driven devices, the conductive two-dimensional material layer is typically nanometer-thick. In practical applications (such as bonding with silicon device surfaces, or adding a substrate layer below the conductive two-dimensional material layer to accommodate a gate), the smoothness of the surface of the nanometer-thick conductive two-dimensional material layer is easily affected, leading to increased resistance when the movable two-dimensional material slides on the surface of the conductive two-dimensional material layer. Therefore, a transition two-dimensional material layer can be placed below the conductive two-dimensional material layer to shield the conductive two-dimensional material layer from the roughness of external contacts, avoiding adverse effects caused by the application scenario on the sliding of the movable two-dimensional material on the surface of the conductive two-dimensional material layer.

[0042] As a preferred embodiment of any technical solution in the first aspect of the present invention, the area of ​​the transition two-dimensional material layer is larger than that of the conductive two-dimensional material layer.

[0043] As a preferred embodiment of any technical solution in the first aspect of the present invention, the thickness of the transition two-dimensional material layer is 9.7~100nm.

[0044] More preferably, the thickness of the transition two-dimensional material layer is 9.7~60 nm;

[0045] More preferably, the thickness of the transition two-dimensional material layer is 10~30 nm.

[0046] As a preferred embodiment of any technical solution in the first aspect of the present invention, the movable two-dimensional material is layered (hereinafter referred to as a movable two-dimensional material layer), and the thickness of the layer is 0.3 ~ 20 nm.

[0047] More preferably, the thickness of the movable two-dimensional material layer is 3~20 nm;

[0048] More preferably, the thickness of the movable two-dimensional material layer is 3~10 nm.

[0049] As a preferred embodiment of any technical solution of the first aspect of the present invention, the material of the first metal electrode includes one or more of titanium, chromium, gold, and platinum.

[0050] The material of the second metal electrode includes one or more of titanium, chromium, gold, and platinum.

[0051] As a preferred embodiment of any technical solution in the first aspect of the present invention, the thickness of the first metal electrode is 10 to 200 nm;

[0052] The thickness of the second metal electrode is 10 ~ 200 nm.

[0053] Furthermore, the thickness of the first metal electrode can be any value within the following range: 10~200, 10~60, 10~100, 60~100, 60~200, 100~200;

[0054] The thickness of the second metal electrode can be any value within the following range: 10~200, 10~60, 10~100, 60~100, 60~200, 100~200.

[0055] More preferably, the thickness of the first metal electrode is 60~100 nm; the thickness of the second metal electrode is 60~100 nm.

[0056] As a preferred embodiment of any technical solution in the first aspect of the present invention, the superlubricated van der Waals heterojunction further includes a substrate, which is placed below the two-dimensional material platform.

[0057] As a preferred embodiment of any technical solution in the first aspect of the present invention, the material of the substrate includes one or more of silicon wafers, sapphire, mica, and polydimethylsiloxane.

[0058] It should be noted that the silicon wafer is a silicon substrate with a silicon oxide layer on its surface, i.e., SiO2. x / Si substrate. When the substrate is SiO x When the substrate is Si, the surface is SiO x The insulating surface is in contact with a conductive two-dimensional material layer or a transitional two-dimensional material layer, and the Si surface can be selectively configured with a gate.

[0059] As a preferred embodiment of any technical solution in the first aspect of the present invention, the superlubricated van der Waals heterojunction further includes a gate disposed on the substrate.

[0060] As a preferred embodiment of any technical solution in the first aspect of the present invention, the gate is made of the same material as the first metal electrode and the second metal electrode, and also needs to be connected to an external circuit to realize the input of voltage signal.

[0061] A second aspect of the present invention provides a method for preparing an electrically driven device with superlubricated interface slippage, comprising:

[0062] Step 1: Prepare a movable two-dimensional material and a two-dimensional material platform, wherein the two-dimensional material platform includes a conductive two-dimensional material layer.

[0063] The movable two-dimensional material is then stacked on the surface of the conductive two-dimensional material layer of the two-dimensional material platform;

[0064] Step 2: Prepare the first metal electrode and the second metal electrode on the conductive two-dimensional material layer obtained in Step 1 using electron beam exposure and metal electrode deposition processes.

[0065] As a preferred embodiment of any technical solution in the second aspect of the present invention, step 1 employs a transfer technique to prepare a movable two-dimensional material and a two-dimensional material layer. The transfer technique can be a dry transfer technique, where the van der Waals interface does not come into contact with any solution reagents during the manufacturing process to ensure the interface is as clean as possible; or it can be a wet transfer technique, where contact with solution reagents is possible during the manufacturing process. Both dry and wet transfer techniques are conventional methods for preparing two-dimensional material heterostructures.

[0066] As a preferred embodiment of any technical solution in the second aspect of the present invention, in step 1, the two-dimensional material platform further includes a transitional two-dimensional material layer, wherein the transitional two-dimensional material layer, the conductive two-dimensional material layer, and the movable two-dimensional material are stacked sequentially from bottom to top.

[0067] As a preferred embodiment of any technical solution in the second aspect of the present invention, step 1 further includes preparing a substrate, wherein a substrate, a transitional two-dimensional material layer, a conductive two-dimensional material layer, and a movable two-dimensional material are stacked sequentially from bottom to top.

[0068] Based on the preparation method provided by any of the technical solutions of the second aspect of the present invention, an electric drive device with super-lubricated interface slippage as described in any of the technical solutions of the first aspect of the present invention can be prepared.

[0069] A third aspect of the present invention provides a microelectromechanical system (MEMS) drive device, the MEMS drive device comprising an electric drive device for superlubricated interface sliding provided by any of the technical solutions of the first aspect of the present invention, or an electric drive device for superlubricated interface sliding prepared by any of the technical solutions of the second aspect of the present invention;

[0070] In addition, an external excitation power supply is electrically connected to the first metal electrode and the second metal electrode of the electrically driven device that slides through the super-lubricated interface.

[0071] A fourth aspect of the present invention provides a microelectromechanical system, the microelectromechanical system comprising an electrically driven device for superlubricated interface sliding provided by any of the technical solutions of the first aspect of the present invention, or an electrically driven device for superlubricated interface sliding obtained by any of the technical solutions of the second aspect of the present invention.

[0072] Alternatively, the microelectromechanical system may include a microelectromechanical system drive device provided by any of the technical solutions of the third aspect of the present invention.

[0073] The fifth aspect of this invention provides an electrically driven sliding method for a superlubricated interface, comprising the steps of:

[0074] Step A: Prepare an electric drive device for super-lubricated interface slippage as described in any of the technical solutions of the first aspect of the present invention, or an electric drive device for super-lubricated interface slippage obtained by the method provided in any of the technical solutions of the second aspect of the present invention;

[0075] And connect the first and second metal electrodes of the electrically driven device that slides the super-lubricated interface to an external excitation power supply;

[0076] Step B: Adjust the external excitation power supply to make the current density of the conductive two-dimensional material layer greater than 0.1 mA / μm, and drive the sliding direction of the movable two-dimensional material (110) on the conductive two-dimensional material layer (121);

[0077] The output voltage of the external excitation power supply ranges from 1 to 200 V, and the voltage output time is from 1 μs to 100 s.

[0078] The angle between the sliding direction of the movable two-dimensional material on the conductive two-dimensional material layer and the current direction is 0° or 180°.

[0079] As a preferred embodiment of any technical solution in the fifth aspect of the present invention, the voltage input form of the external excitation power supply includes one or both of regulated continuous input and pulse voltage input.

[0080] It should be noted that the output form of the external excitation power supply determines the movement mode of the movable two-dimensional material on the conductive two-dimensional material layer: a constant voltage input can realize long-distance sliding of the van der Waals interface, the longest distance of which is determined by the length of the conductive two-dimensional material layer; a short-time pulse voltage input can realize step control of the sliding of the van der Waals interface. Due to measurement limitations, the shortest step distance that can be observed at present is 25nm, and the actual movement distance may be even smaller.

[0081] As a preferred embodiment of any technical solution in the fifth aspect of the present invention, the output voltage of the external excitation power supply is in the range of 5~100 V; the voltage output time is 1ms~1s.

[0082] More preferably, the output voltage of the external excitation power supply is in the range of 5~50 V.

[0083] It should be noted that the magnitude, direction, and duration of the external excitation power supply input voltage can regulate the movement of the movable two-dimensional material on the conductive two-dimensional material layer. Generally speaking, the larger the external excitation power supply input voltage and the longer the duration, the longer the sliding length of the movable two-dimensional material on the van der Waals interface. The direction of the external excitation power supply input voltage controls the current direction on the conductive two-dimensional material layer, while the movement direction of the movable two-dimensional material is controlled by both the current direction and the properties of the movable two-dimensional material itself. When the movable two-dimensional material remains unchanged, controlling the voltage direction (i.e., the current direction) can regulate the movement direction of the movable two-dimensional material.

[0084] As a preferred embodiment of any technical solution in the fifth aspect of the present invention, the electrically driven device for ultra-lubricated interface sliding further includes a gate; in step B, the range of adjusting the gate voltage is -100 ~ 100 V.

[0085] Furthermore, the gate voltage ranges from -50 to 50 V.

[0086] It should be noted that the gate voltage affects the movement state of the movable two-dimensional material on the conductive two-dimensional material layer. The sliding speed of the movable two-dimensional material can be adjusted by adjusting the gate voltage. When the gate voltage reaches a certain value, the sliding speed of the movable two-dimensional material is faster.

[0087] Beneficial effects

[0088] In summary, compared with the prior art, the electric drive method of the present invention has the following main technical advantages:

[0089] (1) The electric drive device for superlubricated interface sliding provided by the present invention uses a two-dimensional material to construct a superlubricated van der Waals heterojunction. Since the lattice constant of the conductive two-dimensional material layer is greater than 1.8% different from the lattice constant of the movable two-dimensional material, the friction coefficient between the movable two-dimensional material and the conductive two-dimensional material layer is low; and the surface roughness of the conductive two-dimensional material itself is less than 2nm. Therefore, the friction between the movable two-dimensional material and the conductive two-dimensional material layer is further reduced, and the friction can be close to zero, effectively avoiding the interface wear problem caused by the relative sliding of silicon-based interfaces in the prior art.

[0090] Based on this, applying the electro-actuated device for ultra-lubricated interface sliding provided by the present invention to the field of microelectromechanical systems (MEMS) technology can effectively improve the service life of MEMS based on van der Waals material systems.

[0091] (2) The electric drive device for ultra-lubricated interface sliding provided by the present invention can realize the driving of structural components with nanometer-level precision, thereby realizing the transport of micro-nano materials with nanometer-level precision and the assembly of devices in the horizontal direction.

[0092] Based on this, while meeting the sensitivity and accuracy requirements of microelectromechanical systems (MEMS), applying the electro-actuated device for ultra-lubricated interface sliding provided by this invention to the field of MEMS technology can further reduce the size of MEMS and achieve miniaturization of MEMS.

[0093] (3) The microelectromechanical system drive device and microelectromechanical system provided by the present invention can further reduce the size while meeting the sensitivity and accuracy requirements, realize the miniaturization of microelectromechanical system, meet the "small size and integration requirements"; and the microelectromechanical system prepared has a long service life.

[0094] (4) The superlubricating interface electro-driven sliding method provided by the present invention can control the sliding distance, direction and speed of the movable two-dimensional material by adjusting the form, direction and magnitude of the applied voltage on the superlubricating van der Waals heterojunction based on two-dimensional material, and achieve a minimum step distance of 25nm, providing the possibility for further technological innovation of micro-nano electromechanical drive system. Attached Figure Description

[0095] Figure 1 This is a schematic diagram of an electrically driven device structure for ultra-lubricated interface slippage in this invention;

[0096] Figure 2 This is a schematic diagram of the structure of the electrically driven device for the sliding of the super-lubricated interface in Example 1;

[0097] Figure 3 These are atomic force morphology diagrams and corresponding electrical excitation curves of electrically excited sliding on the superlubricated van der Waals heterojunction in Example 1; wherein:

[0098] Figure 3 (a) is the atomic force morphology of the heterojunction before the application of an external 30V-1s electrical excitation;

[0099] Figure 3 (b) shows the curves of the pulse voltage and current applied to the heterojunction for 30V-1s as a function of time;

[0100] Figure 3 (c) is the atomic force morphology of the heterojunction after being electrically excited by 30V-1s;

[0101] Figure 3 (d) is the atomic force morphology of the heterojunction before the application of an external 38V-0.1s electrical excitation;

[0102] Figure 3(e) shows the curves of the pulse voltage and current applied to the heterojunction for 38V-0.1s as a function of time;

[0103] Figure 3 (f) is the atomic force morphology of the heterojunction after being electrically excited by 38V for 0.1s;

[0104] Figure 4 This is a schematic diagram showing the movement position of the superlubricated van der Waals heterojunction under multiple electrical excitation drives in Example 2; wherein:

[0105] Figure 4 (a) is the atomic force morphology of the heterojunction before external electrical excitation;

[0106] Figure 4 (b) ~ Figure 4 (d) shows the location of the heterojunction after multiple electrical excitations;

[0107] Figure 5 This is a schematic diagram showing the movement of the heterojunction under electrical excitation after the electrode orientation is reversed in Example 2; wherein,

[0108] Figure 5 (a) is the atomic force morphology of the heterojunction before external electrical excitation;

[0109] Figure 5 (b) is the atomic force morphology of the heterojunction after external electrical excitation;

[0110] Figure 6 This is an image showing the electrically excited movement distance of the molybdenum disulfide / graphene / hexagonal boron nitride heterojunction in Example 3; wherein,

[0111] Figure 6 (a) is a schematic diagram of the field-effect transistor structure of this heterojunction;

[0112] Figure 6 (b) shows the resistance characteristics of the graphene channel as a function of the gate voltage and the distance the molybdenum disulfide moves as a function of the gate voltage under the same pulse voltage excitation.

[0113] Figure 7 The figures show the atomic force amplitude diagram, electron microscopy image, and corresponding electrical excitation curve of electrically excited sliding on the hexagonal boron nitride / graphene / hexagonal boron nitride heterojunction in Comparative Example 1; among them,

[0114] Figure 7 (a) is the atomic force amplitude diagram of the heterojunction before the application of an external 50V-0.1s electrical excitation;

[0115] Figure 7 (b) is an electron microscope image of the heterojunction after being electrically excited by 50V for 0.1s.

[0116] Explanation of the labels in the attached drawings:

[0117] 100. Superlubricated van der Waals heterojunction;

[0118] 110. Movable two-dimensional materials;

[0119] 120. Two-dimensional material platform; 121. Conductive two-dimensional material layer; 122. Transitional two-dimensional material layer;

[0120] 130. Base;

[0121] 210, First metal electrode; 220, Second metal electrode; 230, Gate electrode;

[0122] I. Current; A. Initial position; B. Final position. Detailed Implementation

[0123] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Embodiments of the present invention will be described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0124] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0125] It should be noted that terms such as "upper", "lower", "left", "right", and "middle" used in this specification are only for clarity of description and are not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as within the scope of this application.

[0126] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0127] As used herein, the term “about” is used to provide for the flexibility and imprecision associated with a given term, measure, or value. Those skilled in the art can readily determine the degree of flexibility for a particular variable.

[0128] As used herein, the term “at least one of…” is intended to be synonymous with “one or more of…”. For example, “at least one of A, B, and C” explicitly includes only A, only B, only C, and combinations thereof.

[0129] As used in this article, the definition of the term "layer" is not limited to "consistent thickness" or "having clear dividing lines." Its core is the relatively independent and orderly distribution based on properties such as matter, structure, and function. The specific meaning needs to be flexibly understood in conjunction with the context (such as geography, materials, biology, mathematics, etc.).

[0130] As used herein, the terms "two-dimensional material," "movable two-dimensional material," "conductive two-dimensional material layer," "transitional two-dimensional material layer," and "two-dimensional material platform" should be understood as materials with a layered structure and an atomically flat surface, which is the core characteristic that distinguishes them from three-dimensional materials. Therefore, unless otherwise specified, the surface roughness of the two-dimensional materials involved in this invention should be considered to have an atomically flat surface.

[0131] Concentration, amount, and other numerical data may be presented in range format herein. It should be understood that such range format is used solely for convenience and brevity and should be flexibly interpreted to include not only the values ​​explicitly stated as the limits of the range, but also all individual values ​​or subranges encompassed within the range, as if each value and subrange were explicitly stated. For example, a range of values ​​from about 1 to about 4.5 should be interpreted to include not only the explicitly stated limits of 1 to 4.5, but also individual numbers (such as 2, 3, 4) and subranges (such as 1 to 3, 2 to 4, etc.). The same principle applies to ranges that describe only a single value, such as "less than about 4.5," which should be interpreted to include all the values ​​and ranges described above. Furthermore, this interpretation should apply regardless of the breadth of the range or characteristic described.

[0132] 1. Structural description of the electrically driven device for ultra-lubricated interface slippage provided by the present invention:

[0133] like Figure 1 As shown in Figure 2, the electrically driven device for superlubricated interface slippage provided by the present invention includes a superlubricated van der Waals heterojunction 100, a first metal electrode 210 and a second metal electrode 220 connected to the superlubricated van der Waals heterojunction 100.

[0134] The superlubricated van der Waals heterojunction 100 includes a two-dimensional material platform 120 with a conductive two-dimensional material layer 121 on its surface, and a movable two-dimensional material 110 stacked on the surface of the two-dimensional material platform 120. A first metal electrode 210 and a second metal electrode 220 are respectively connected to the two ends of the conductive two-dimensional material layer 121. When the first metal electrode 210 and the second metal electrode 220 are electrically connected to an external excitation power supply, a certain current density is generated on the conductive two-dimensional material layer 121 by adjusting the input voltage of the external excitation power supply. This allows the movable two-dimensional material 110 to slide on the surface of the conductive two-dimensional material layer 121 via electrical drive.

[0135] Typically, it is required that the lattice constant of the conductive two-dimensional material layer 121 differs from that of the movable two-dimensional material 110 by more than 1.8%. This is because the movable two-dimensional material 110 and the conductive two-dimensional material layer 121 are bonded only by van der Waals forces, which are much weaker than covalent bonds. When the difference in lattice constants between the two two-dimensional materials exceeds 1.8%, lattice mismatch can occur, forming a non-common interface at the contact surface between the conductive two-dimensional material and the movable two-dimensional material 110. This interface has a low coefficient of friction, approaching zero, and is called a super-lubricating interface. Based on this, the sliding potential energy at this interface can also approach zero. Therefore, under the action of an external excitation voltage, the movable two-dimensional material 110 slides on the surface of the conductive two-dimensional material layer 121. Furthermore, due to the low interfacial friction and low mechanical wear, the lifespan of the electrically driven device with the super-lubricating interface sliding provided by this invention can be extended to hundreds of times or more than that of conventional materials. Furthermore, based on the foregoing, the difference between the lattice constant of the conductive two-dimensional material layer and the lattice constant of the movable two-dimensional material can be 2.0% to 400%, preferably 5.0% to 300%, and more preferably 10% to 200%.

[0136] In addition, in order to further ensure that the frictional force is as small as possible when the movable two-dimensional material 110 moves on the conductive two-dimensional material layer 121, the surface roughness (Ra) of the conductive two-dimensional material layer 121 on the side in contact with the movable two-dimensional material 110 is required to be less than 2 nm, preferably less than 1 nm.

[0137] Based on the above information, regarding the materials used, the conductive two-dimensional material layer 121 can be made of materials such as graphene, transition metal compounds, or one or more of these materials, and the movable two-dimensional material 110 can be made of materials such as hexagonal boron nitride, graphene, transition metal compounds, or one or more of these materials, and the movable two-dimensional material 110 is not made of the same material as the conductive two-dimensional material layer 121.

[0138] The thickness of the two-dimensional material platform 120 is required to be no less than 10 nm. To reduce interfacial friction during sliding while meeting the requirements of miniaturization and integration, a thickness of 10–200 nm is generally recommended, preferably 30.3–100.3 nm. A certain thickness of the two-dimensional material platform 120 prevents it from curling due to excessive thinness, which would affect the sliding path of the movable two-dimensional material 110 on its surface. In terms of size, the thickness of the conductive two-dimensional material layer 121 can range from 0.3–100 nm, preferably 0.3–30 nm, and even more preferably 0.3–9.7 nm. The movable two-dimensional material 110 is typically layered (i.e., a movable two-dimensional material layer), and the size of the movable two-dimensional material layer is typically smaller than the size of the conductive two-dimensional material layer 121. The thickness of the movable two-dimensional material layer is 0.3–20 nm, preferably 3–20 nm, and even more preferably 3–10 nm. Regarding the composition of the two-dimensional material platform 120, it may consist only of a conductive two-dimensional material layer 121, or it may include a conductive two-dimensional material layer 121 and a transitional two-dimensional material layer 122 disposed beneath the conductive two-dimensional material layer 121. Typically, if the thickness of the conductive two-dimensional material layer 121 meets the requirements, or if the operating environment no longer presents external contact roughness that could affect the roughness of the sliding surface provided by the conductive two-dimensional material layer, the two-dimensional material platform 120 may consist only of the conductive two-dimensional material layer 121. A second typical scenario is that, in certain situations, due to the "minimal size and integration requirements" of microelectromechanical systems (MEMS), the conductive two-dimensional material layer 121 is required to maintain a relatively low thickness within the range of 0.3~100 nm. In practical applications (such as bonding with silicon device surfaces, or adding a substrate 130 layer below the two-dimensional material to accommodate a gate 230), the smoothness of the conductive two-dimensional material layer 121's surface is easily affected by external contacts, leading to increased resistance when the movable two-dimensional material 110 slides on the surface of the conductive two-dimensional material layer 121. For example, when the conductive two-dimensional material layer 121 is 1 nm thick, if it needs to be placed on other silicon devices, the uneven surface of the silicon material will affect the smoothness of the conductive two-dimensional material layer 121's surface, thereby increasing the sliding resistance of the movable two-dimensional material 110 at the interface. In this case, as a preferred embodiment, the two-dimensional material platform 120 needs to simultaneously include the conductive two-dimensional material layer 121 and a transition two-dimensional material layer 122 disposed beneath the conductive two-dimensional material layer 121, i.e. Figure 2As shown, the two-dimensional material platform 120 includes a double-layer structure. In this case, the transitional two-dimensional material layer 122 can effectively shield the influence of external contact roughness on the conductive two-dimensional material layer 121. In terms of size, the area of ​​the transitional two-dimensional material layer 122 is greater than or equal to the area of ​​the conductive two-dimensional material layer 121, and the thickness of the transitional two-dimensional material layer 122 is typically 9.7~100 nm. Regarding materials, the transitional two-dimensional material layer 122 is made of one or more of hexagonal boron nitride, graphene, and transition metal compounds.

[0139] The first metal electrode 210 and the second metal electrode 220 are each independently made of one or more of titanium, chromium, gold, and platinum. In terms of size, the thickness of both the first metal electrode 210 and the second metal electrode 220 is 10-200 nm. Further, the thickness of the first metal electrode 210 and the second metal electrode 220 can be independently taken from any of the following numerical ranges: 10-200, 10-60, 10-100, 60-100, 60-200, 100-200. More preferably, the thickness of the first metal electrode 210 is 60-100 nm. Furthermore, as... Figure 2 As shown, the first metal electrode 210 and the second metal electrode 220 can also contact the conductive two-dimensional material layer 121 and the transition two-dimensional material layer 122 simultaneously. While conducting electricity, they can also fix the position between the conductive two-dimensional material layer 121 and the transition two-dimensional material layer 122.

[0140] Furthermore, such as Figure 2 As shown, in some specific embodiments, the superlubricated van der Waals heterojunction 100 further includes a substrate 130, which is disposed below the two-dimensional material layer. The material of the substrate 130 is selected from silicon wafers, sapphire, mica, and polydimethylsiloxane. The silicon wafer is a silicon substrate with a silicon oxide layer on its surface, i.e., SiO2. x / Si substrate. When the substrate is SiO x When the substrate is Si, the surface is SiO x One side of the material is in contact with the conductive two-dimensional material layer 121 or the transition two-dimensional material layer 122, and the other side, which is Si, can selectively have a gate 230. The gate 230 is the same as the first metal electrode 210 and the second metal electrode 220, and needs to be connected to an external circuit to realize the input of a voltage signal. When the gate voltage is input through an external excitation power supply, the sliding speed of the movable two-dimensional material 110 on the surface of the conductive two-dimensional material layer 121 can be adjusted.

[0141] Based on the above, the microelectromechanical system drive device of the present invention is formed by electrically connecting the external excitation power supply to the electrode of any of the above-described super-lubricated interface sliding electric drive devices.

[0142] A microelectromechanical system comprising any of the above-described electro-hydraulic interface sliding devices or microelectromechanical system drive devices constitutes the microelectromechanical system of the present invention.

[0143] 2. Explanation of the working principle of the electrically driven device for ultra-lubricated interface slippage provided by this invention:

[0144] The electrically driven device for superlubricated interface slippage provided by the present invention includes a superlubricated van der Waals heterojunction 100, a first metal electrode 210 and a second metal electrode 220 connected to the superlubricated van der Waals heterojunction 100.

[0145] First, when the first metal electrode 210 and the second metal electrode 220 are electrically connected to the external excitation power supply, current flows through the conductive two-dimensional material layer 121 in the superlubricated van der Waals heterojunction 100. Since the material of the conductive two-dimensional material layer 121 is selected from hexagonal boron nitride, graphene, transition metal compounds, and other two-dimensional materials with piezoelectric effects (i.e., these two-dimensional materials deform under the action of an applied electric field or mechanical stress, or undergo mechanical motion through changes in the electric field), it has been found that by adjusting the input voltage of the external excitation power supply, the movable two-dimensional material 110 can slide on the surface of the conductive two-dimensional material layer 121, such as... Figure 1 As shown in Figure 2, the movable two-dimensional material 110 moves from the initial position A to the final position B under voltage.

[0146] Secondly, since the movable two-dimensional material 110 and the conductive two-dimensional material layer 121 are bonded only by van der Waals forces, the force is much weaker than that of covalent bonds. When the lattice constant difference between the two two-dimensional materials is greater than 1.8%, a non-common interface is formed at the contact surface between the conductive two-dimensional material and the movable two-dimensional material 110 due to lattice mismatch. This interface has a low coefficient of friction, which can approach zero, and is called a superlubricating interface. Such two two-dimensional materials are also called a superlubricating van der Waals heterojunction 100. Since the frictional force can approach zero, the sliding potential energy on this superlubricating interface can also approach zero. Therefore, under the action of an external excitation voltage, the movable two-dimensional material 110 can slide on the surface of the conductive two-dimensional material layer 121. The movable two-dimensional material 110 can transport micro- and nano-materials and realize the precise assembly of devices in the horizontal direction as needed. Furthermore, due to the low interface friction and low mechanical wear, the lifespan of the electric drive device with the superlubricating interface sliding provided by this invention can be extended to hundreds of times or more than that of electric drive devices made of conventional materials.

[0147] Based on this, the movement state of the movable two-dimensional material 110 on the conductive two-dimensional material layer 121 can be adjusted by the magnitude, direction, and duration of the external excitation power supply input voltage. Generally, the larger the external excitation power supply input voltage and the longer the duration, the longer the sliding length of the movable two-dimensional material 110 on the van der Waals interface; the direction of the external excitation power supply input voltage controls the current direction on the conductive two-dimensional material layer 121, and thus the movement direction of the movable two-dimensional material 110 can be controlled by adjusting the voltage direction.

[0148] Furthermore, when the electrically driven device for sliding the super-lubricated interface is provided with a gate 230, the sliding speed of the movable two-dimensional material 110 can be adjusted by adjusting the gate voltage. When the gate voltage reaches a certain value, the sliding speed is faster.

[0149] 3. Description of the preparation method of the electrically driven device with super-lubricated interface slip provided by the present invention:

[0150] The method for preparing the electrically driven device for superlubricated interface slip provided by the present invention is as follows:

[0151] Step 1: Prepare a movable two-dimensional material 110 and a two-dimensional material platform 120, wherein the two-dimensional material platform 120 includes a conductive two-dimensional material layer 121;

[0152] The movable two-dimensional material 110 is then stacked on the surface of the conductive two-dimensional material layer 121 of the two-dimensional material platform 120;

[0153] Step 2: The first metal electrode 210 and the second metal electrode 220 are fabricated on the conductive two-dimensional material layer 121 obtained in Step 1 using electron beam lithography and metal electrode deposition processes.

[0154] In step 1, a transfer technique is used to prepare the movable two-dimensional material 110 and the two-dimensional material platform 120. This transfer technique can be either a dry transfer technique or a wet transfer technique. Both dry and wet transfer techniques are conventional methods for preparing two-dimensional material heterostructures. For example, the dry transfer process typically involves: adhering polydimethylsiloxane (PDMS) coated with a polycarbonate (PC) film onto a transparent glass slide; then, inverting and suspending the entire support onto an XYZR four-dimensional adjustable cantilever; under an optical microscope, lowering the cantilever height allows the PC film to adhere to the pre-mechanically peeled two-dimensional material (e.g., [missing information]). Figure 2 The conductive two-dimensional material layer 121 is bonded, adhered, and separated. If multi-layer two-dimensional materials are to be prepared, the bonding and separation are performed layer by layer. Then, it is brought into full contact with the substrate (e.g., substrate 130) (SiO2 / Si) to which the two-dimensional material is to be transferred, and pressed. The temperature is increased to melt and detach the PC film, thus obtaining a supporting substrate (e.g., a two-dimensional material heterostructure) with a two-dimensional material heterostructure. Figure 2The substrate 130 in the middle). Subsequently, the polymer film is removed to obtain a two-dimensional material heterostructure (e.g., substrate 130). Figure 2 (Superlubricated van der Waals heterojunction 100).

[0155] 4. Description of the electrically driven sliding method for the super-lubricated interface provided by this invention:

[0156] The electrically driven sliding method for a super-lubricated interface provided by this invention includes the following steps:

[0157] Step A: Prepare the electric drive device for super-lubricated interface sliding as described in any technical solution of the present invention, and electrically connect the first metal electrode 210 and the second metal electrode 220 of the electric drive device for super-lubricated interface sliding to an external excitation power supply.

[0158] Step B: Adjust the external excitation power supply to make the current density of the conductive two-dimensional material layer 121 greater than 0.1 mA / μm;

[0159] The output voltage of the external excitation power supply ranges from 1 to 200 V, and the voltage output time is from 1 μs to 100 s.

[0160] The sliding direction of the movable two-dimensional material 110 on the conductive two-dimensional material layer 121 forms an angle of 0° or 180° with the current direction.

[0161] When the gate 230 is provided, the schematic diagram of the electric drive device structure for ultra-lubricated interface slippage is as follows. Figure 6 As shown in (a).

[0162] The input form of the external excitation power supply voltage specifically includes one or both of regulated continuous input and pulse voltage input. The output form of the external excitation power supply determines the movement mode of the movable two-dimensional material 110 on the conductive two-dimensional material layer 121: regulated continuous input can realize long-distance sliding of the van der Waals interface, the maximum distance of which is determined by the length of the conductive two-dimensional material layer 121; short-time pulse voltage input can realize step control of the van der Waals interface sliding. Due to measurement limitations, the shortest step distance that can be observed so far is 25nm, and the actual movement distance may be even smaller.

[0163] The magnitude, direction, and duration of the external excitation power supply input voltage can adjust the movement state of the movable two-dimensional material 110 on the conductive two-dimensional material layer 121. Generally, the larger the external excitation power supply input voltage and the longer the duration, the longer the sliding length of the movable two-dimensional material 110 on the van der Waals interface; the direction of the external excitation power supply input voltage controls the current direction on the conductive two-dimensional material layer 121. The movement direction of the movable two-dimensional material 110 is determined by the current direction (…). Figure 1 or Figure 2The movement direction is controlled by two factors: the current (I represents the electric current) and the properties of the movable two-dimensional material itself. For example, when the movable two-dimensional material 110 is molybdenum disulfide, the movement direction is opposite to the current direction; while when the movable two-dimensional material 110 is tungsten diselenide, its movement direction is the same as the current direction. It should be noted that because the interfacial friction coefficient between the movable two-dimensional material and the conductive two-dimensional material is very low, the surface roughness of the conductive two-dimensional material has a relatively greater impact on the slippage. Furthermore, the surface roughness of the conductive two-dimensional material cannot be guaranteed to be completely uniform across every part. Therefore, the movement direction of the movable two-dimensional material does not necessarily form a strictly 0° or 180° angle with the current direction for every small segment of displacement; the general direction of movement is either the same as or opposite to the current direction.

[0164] Furthermore, the gate voltage can adjust the sliding speed of the movable two-dimensional material 110. When the gate voltage reaches a certain value, such as... Figure 6 As shown in (b), the sliding speed increases when the gate voltage reaches 20V.

[0165] The output voltage of the external excitation power supply is in the range of 1 ~ 200 V; preferably, the voltage range is 5 ~ 100 V; more preferably, the voltage range is 5 ~ 50 V; the voltage output time is 1 μs ~ 100 s; preferably, the voltage output time is 1 ms ~ 1 s; the gate voltage is in the range of -100 ~ 100 V; preferably, the voltage range is -50 ~ 50 V.

[0166] Example 1

[0167] 1) In this embodiment, a dry transfer method was used to prepare the following... Figure 2 The superlubricated van der Waals heterojunction 100 shown contains a movable two-dimensional material 110 made of molybdenum disulfide. In this embodiment, three molybdenum disulfide fragments were prepared with thicknesses of 3, 4, and 6 nm, respectively. Figure 3 As shown in (a), the conductive two-dimensional material layer 121 is a single layer of graphene with a thickness of 0.34 nm, and its surface roughness is guaranteed to be less than 1 nm; the transition two-dimensional material layer 122 is made of hexagonal boron nitride with a thickness of 30 nm. This superlubricated van der Waals heterojunction 100 can be referred to as a "molybdenum disulfide / graphene / hexagonal boron nitride heterojunction", wherein the "conductive two-dimensional material layer 121" is conventionally referred to as the channel in the art, and specifically described as a graphene channel in this embodiment.

[0168] 2) Using a Zeiss Sigma 300 field emission electron microscope and a Raith pattern generator, electrode patterns were exposed on graphene. A Quorum 150T Plus high-vacuum ion sputtering system was then used to place the exposed heterojunction within the sputtering chamber. Titanium (3nm thick) and gold (57nm thick) metal targets were selected, and the sputtering was performed at a vacuum of 10... -5 Under the condition of mbar, a sputtering current of 20 mA and a sputtering time of 300 s were used to prepare a first metal electrode 210 and a second metal electrode 220 made of titanium and gold at both ends of graphene. The titanium coating is 3 nm thick and is in direct contact with the graphene. The gold coating is deposited on the titanium coating and has a thickness of 57 nm. Finally, the first metal electrode 210 and the second metal electrode 220 with a metal coating thickness of 60 nm are distributed at both ends of the graphene channel.

[0169] 3) Connect the first metal electrode 210 and the second metal electrode 220 at both ends of the graphene channel to the positive and negative terminals of a Keithley 2400 high-precision multimeter (which serves as an external excitation power source to provide a precise voltage and current source and can measure it) using silver paste wires, and place them in the atomic force sample chamber.

[0170] 4) The initial position of molybdenum disulfide on graphene / hexagonal boron nitride was characterized using an atomic force microscope (AFM) of Oxford University (model Cypher ES). After applying a pulse voltage of 30 V to the graphene channel for 1 s, the position distribution of molybdenum disulfide on it was characterized again to understand the movement of the molybdenum disulfide sheet. This voltage condition is denoted as 30 V - 1 s.

[0171] 5) Based on 4), try changing the voltage applied to the graphene channel to a pulse voltage of 38 V for a duration of 0.1 s, and observe the movement of the molybdenum disulfide sheet. This voltage is recorded as: 38V-0.1s.

[0172] Figure 3 (a) is an atomic force morphology diagram of the molybdenum disulfide / graphene / hexagonal boron nitride heterojunction in this embodiment before applying an external 30V-1s electrical excitation. The distribution of the heterojunction can be observed in the figure, where the thickness of molybdenum disulfide is marked in white, and the positions of molybdenum disulfide, graphene, the first metal electrode 210, and the second metal electrode 220 are marked with red, black, and green dashed lines, respectively. The specific image showing the distribution of molybdenum disulfide on the graphene / hexagonal boron nitride after applying an external 30V-1s electrical excitation to the graphene channel is shown below. Figure 3 As shown in (c), in comparison Figure 3 (c) and Figure 3(a) The results show that the moving distance of the three molybdenum disulfide sheets ranges from 200 nm to 3 μm, and their moving direction is opposite to the direction of the current. Figure 3 (b) shows the voltage and current changes in the graphene channel during the application of an external 30V-1s electrical excitation.

[0173] Figure 3 (d) is the atomic force morphology diagram of the molybdenum disulfide / graphene / hexagonal boron nitride heterojunction in this embodiment before the external 38V-0.1s electrical excitation. Two white parallel lines perpendicular to the current direction are drawn as the baseline. One of them intersects with the edge of the observed molybdenum disulfide sheet, which is used as the starting point of the movement of molybdenum disulfide. Figure 3 (f) is the atomic force morphology of the molybdenum disulfide / graphene / hexagonal boron nitride heterojunction in this embodiment after an external electrical excitation of 38V-0.1s. The edge of the molybdenum disulfide structure furthest from the starting point intersects with the red line, which is perpendicular to the current direction. (Comparison) Figure 3 (f) and Figure 3 (d) shows the position of the molybdenum disulfide sheet. The molybdenum disulfide sheet moves from the starting position (lower right white line) to the ending position (red line) in the opposite direction to the current. The measurement results show that the minimum moving distance of the molybdenum disulfide sheet can reach 25 nm. Figure 3 (e) shows the voltage and current changes in the graphene channel during the external 38V-0.1s electrical excitation process.

[0174] It should be noted again that due to limitations in characterization methods (the minimum detection limit of atomic force microscopy (cypher ES) regarding differences in surface morphology positions), this embodiment can only detect a minimum migration distance of 25 nm for molybdenum disulfide on the graphene / hexagonal boron nitride heterostructure (e.g., Figure 3 (d)- Figure 3 (f) does not represent that the actual minimum moving distance of the present invention is 25 nm. With the improvement of the sensitivity of the characterization method, it is possible to detect a smaller moving distance.

[0175] Example 2

[0176] 1) In this embodiment, a molybdenum disulfide / graphene / hexagonal boron nitride heterojunction is prepared using a dry transfer method. The heterojunction in this embodiment differs from the "molybdenum disulfide / graphene / hexagonal boron nitride heterojunction" in Example 1 only in that: ① only one molybdenum disulfide fragment is prepared, and the thickness of the molybdenum disulfide fragment is 5 nm; ② the thickness of the hexagonal boron nitride is 60 nm.

[0177] 2) Using a Zeiss Sigma 300 field emission electron microscope and a Raith pattern generator, electrode patterns were exposed on graphene. A Quorum 150T Plus high-vacuum ion sputtering system was then used to place the exposed heterojunction within the sputtering chamber. Titanium (3nm thick) and gold (57nm thick) metal targets were selected, and the sputtering was performed at a vacuum of 10... -5 Under the condition of mbar, a sputtering current of 20 mA and a sputtering time of 300 s were used to prepare a first metal electrode 210 and a second metal electrode 220 made of titanium and gold at both ends of graphene. The titanium coating is 3 nm thick and is in direct contact with the graphene. The gold coating is deposited on the titanium coating and has a thickness of 57 nm. Finally, the first metal electrode 210 and the second metal electrode 220 with a metal coating thickness of 60 nm are distributed at both ends of the graphene channel.

[0178] 3) Connect the first metal electrode 210 and the second metal electrode 220 at both ends of the graphene channel to the positive and negative terminals of a Keithley 2400 high-precision multimeter (which serves as an external excitation power source to provide a precise voltage and current source and can measure it) using silver glue wires, and place it in the atomic force sample chamber;

[0179] 4) The initial position of molybdenum disulfide on graphene / hexagonal boron nitride was characterized using an atomic force microscope (Cypher ES) from Oxford University. A voltage of 47 V was applied to the graphene channel multiple times for a duration of 0.1 s, and the position distribution of molybdenum disulfide on it was continuously characterized in between to understand the movement of the molybdenum disulfide sheet. During this period, the direction of the applied electric field was changed, and the movement of molybdenum disulfide on it was characterized again.

[0180] The specific image of the original molybdenum disulfide / graphene / hexagonal boron nitride heterostructure obtained in this embodiment is as follows: Figure 4 As shown in (a), the movement of the molybdenum disulfide sheet after applying pulse voltages sequentially is as follows. Figure 4 As shown in (b) to (d), the movement of molybdenum disulfide before and after pulse excitation after reversing the electric field direction is as follows. Figure 5 As shown in (a) and (b). In all the above figures, the white arrows indicate the direction of the current, the red marks indicate the position of the molybdenum disulfide at each movement, and the red arrows indicate the direction of movement of the molybdenum disulfide sheet. (Comparison) Figure 4 (b) and Figure 4 (a) Measurements show that the first movement distance of the molybdenum disulfide sheet in this embodiment is 149 nm; in comparison... Figure 4 (c) and Figure 4 (b) Measurements show that the second movement distance of the molybdenum disulfide sheet in this embodiment is 679 nm; in comparison... Figure 4 (d) and Figure 4 (c) Measurements show that the third movement distance of the molybdenum disulfide sheet in this embodiment is 62 nm. Since the graphene interface is difficult to guarantee that the entire surface is completely identical under laboratory conditions, that is, the frictional force of the graphene interface is difficult to guarantee that it is completely identical, the movement distance of molybdenum disulfide will vary slightly each time.

[0181] contrast Figure 5 (b) and Figure 5 (a) shows that after reversing the electric field direction, the movement direction of the molybdenum disulfide sheet also reversed, and its movement distance was 248 nm. This result indicates that the molybdenum disulfide sheet can move directionally under an applied voltage, and its movement direction can be controlled by the direction of the applied electric field. Furthermore, after several sliding tests, no significant damage to the graphene channels was observed throughout the process, indicating that the electro-actuated device with ultra-lubricated interface sliding provided by this invention has low friction and low mechanical wear, and has the potential to extend the lifespan of traditional microelectromechanical drive systems.

[0182] Example 3

[0183] 1) In this embodiment, a dry transfer method was used to prepare the following... Figure 6 (a) shows a superlubricated van der Waals heterojunction 100, in which the movable two-dimensional material 110 is made of molybdenum disulfide with a thickness of 5 nm; the conductive two-dimensional material layer 121 is a single layer of graphene with a thickness of 0.34 nm, and its surface roughness is guaranteed to be less than 1 nm; the transition two-dimensional material layer 122 is made of hexagonal boron nitride with a thickness of 100 nm. A substrate 130 is also provided on this basis. The substrate 130 is made of silicon wafer, which is a silicon substrate with a silicon oxide layer on its surface, i.e., SiO2. x / Si substrate, surface is SiO x One side of the silicon wafer is in contact with the transition two-dimensional material layer 122, and the side with the Si surface is provided with a gate 230. The prepared molybdenum disulfide / graphene / hexagonal boron nitride heterojunction is placed directly on the silicon wafer, and the bottom hexagonal boron nitride layer of the heterojunction is in contact with the side of the silicon wafer without the gate 230.

[0184] 2) Electrode patterns were exposed on graphene using a Zeiss Sigma 300 field emission electron microscope and a Raith pattern generator. The exposed heterojunction was placed in the sputtering chamber using a Quorum 150T Plus high-vacuum ion sputtering system. Titanium (3nm) and gold (97nm) metal targets were selected, and the sputtering was performed at a vacuum of 10... -5Under the condition of mbar, a sputtering current of 20 mA and a sputtering time of 600 s were used to prepare a first metal electrode 210 and a second metal electrode 220 made of titanium and gold at both ends of graphene. The titanium coating is 3 nm thick and is in direct contact with the graphene. The gold coating is deposited on the titanium coating and has a thickness of 97 nm. Finally, the first metal electrode 210 and the second metal electrode 220 with a metal coating thickness of 100 nm are distributed at both ends of the graphene channel.

[0185] 3) Connect the first metal electrode 210 and the second metal electrode 220 at both ends of the graphene channel with silver glue wires to the positive and negative terminals of a Keithley 2400 high-precision multimeter (which serves as an external excitation power supply to provide a precise voltage and current source and can measure it). Use another Keithley 2400 high-precision multimeter to perform gate modulation on the heterojunction sample and place it in the atomic force sample chamber.

[0186] 4) The resistance characteristics of the graphene channel as a function of gate voltage were tested at a low source-drain voltage (5 mV). Subsequently, the initial position of molybdenum disulfide on the graphene / hexagonal boron nitride was characterized using an atomic force microscope (Cypher ES) from Oxford University. The gate voltage was adjusted, and a single pulse voltage of 50 V for 0.1 s was applied to the graphene channel to characterize the position distribution of molybdenum disulfide on it. By repeating this step multiple times, the movement of molybdenum disulfide under the same electrical pulse excitation at different gate voltages can be obtained.

[0187] The resistance characteristics of the graphene channel as a function of gate voltage were tested at a low source-drain voltage (5 mV) as follows: Figure 6 As shown in (b), the purpose is to obtain the types and concentrations of charge carriers in the graphene channel under different gate voltages. The maximum resistance of the channel corresponds to the case where the graphene has no doping.

[0188] The field-effect transistor structure obtained in this embodiment is as follows: Figure 6 As shown in (a), the resistance characteristics of the graphene channel vary with the pulse voltage, and the statistical image of the migration distance of molybdenum disulfide under different gate voltages under the same pulse voltage excitation is shown in the figure. Figure 6 As shown in (b), the graphene channel exhibits drastically different resistance characteristics under different gate voltages. This indicates that the type and concentration of charge carriers in the graphene change significantly, directly affecting the movement of molybdenum disulfide under pulsed excitation. Figure 6As shown in (b), when the gate voltage is 7V, the electron concentration and hole concentration in graphene are equal, and the resistance of the graphene channel is the largest. Within the gate voltage range of -40V to 7V, the moving distance of molybdenum disulfide under a single pulse voltage of 0.1s is basically consistent. However, when the gate voltage is further increased to 20V, the moving distance of molybdenum disulfide under a single pulse voltage of 0.1s suddenly increases. This indicates that when the gate voltage reaches a certain range, it will significantly modulate the movement speed of molybdenum disulfide.

[0189] Example 4

[0190] 1) In this embodiment, a molybdenum disulfide / graphene / hexagonal boron nitride heterojunction is prepared using a dry transfer method. The heterojunction in this embodiment differs from the "molybdenum disulfide / graphene / hexagonal boron nitride heterojunction" in Example 1 only in that: ① only one molybdenum disulfide fragment is prepared, and the thickness of the molybdenum disulfide fragment is 20 nm; ② the thickness of the graphene is 100 nm; ③ the thickness of the hexagonal boron nitride is 100 nm.

[0191] 2) Electrode patterns were exposed on graphene using a Zeiss Sigma 300 field emission electron microscope and a Raith pattern generator. The exposed heterojunction was placed in the sputtering chamber using a Quorum 150T Plus high-vacuum ion sputtering system. Titanium (3 nm) and gold (197 nm) metal targets were selected, and the sputtering was performed at a vacuum of 10... -5 Under the condition of mbar, a sputtering current of 20 mA and a sputtering time of 1200 s were used to prepare a first metal electrode 210 and a second metal electrode 220 made of titanium and gold at both ends of graphene. The titanium coating is 3 nm thick and is in direct contact with the graphene. The gold coating is deposited on the titanium coating and has a thickness of 197 nm. Finally, the first metal electrode 210 and the second metal electrode 220 with a metal coating thickness of 200 nm are distributed at both ends of the graphene channel.

[0192] 3) Connect the metal electrodes at both ends of the graphene channel to the positive and negative terminals of a Keithley 2400 high-precision multimeter (which serves as an external excitation power source to provide a precise voltage and current source and can measure it) using silver paste wires, and place it in the atomic force sample chamber;

[0193] The initial positions of molybdenum disulfide (MoD) on graphene / hexagonal boron nitride were characterized using an atomic force microscope (AFM) from Oxford University. After applying a 50 V voltage to the graphene channel for 1 ms, the positional distribution of MoD on it was further characterized. The results showed that MoD migrated 300 nm in the direction opposite to the current.

[0194] Example 5

[0195] 1) In this embodiment, a dry transfer method was used to prepare the following... Figure 2 The superlubricating van der Waals heterojunction 100 shown includes a movable two-dimensional material 110 made of graphene with a thickness of 0.34 nm; a conductive two-dimensional material layer 121 made of conductive molybdenum disulfide with a thickness of 9.7 nm, ensuring a surface roughness of less than 1 nm; and no transition two-dimensional material layer 122. This superlubricating van der Waals heterojunction 100 can be referred to as a "graphene / molybdenum disulfide heterojunction".

[0196] 2) Using a Zeiss Sigma 300 field emission electron microscope and a Raith pattern generator, electrode patterns were exposed on the molybdenum disulfide channel. A Quorum 150T Plus high-vacuum ion sputtering system was then used to place the exposed heterojunction within the sputtering chamber. Titanium (1 nm) and gold (9 nm) metal targets were selected, and the sputtering was performed at a vacuum of 10... -5 Under the condition of mbar, a sputtering current of 20 mA and a sputtering time of 10 s were used to prepare a first metal electrode 210 and a second metal electrode 220 made of titanium and gold at both ends of the molybdenum disulfide channel. The titanium coating is 1 nm thick and is in direct contact with the molybdenum disulfide. The gold coating is deposited on the titanium coating and has a thickness of 9 nm. Finally, the first metal electrode 210 and the second metal electrode 220 with a metal coating thickness of 10 nm are distributed at both ends of the molybdenum disulfide channel.

[0197] 3) Connect the first metal electrode 210 and the second metal electrode 220 at both ends of the molybdenum disulfide channel to the positive and negative terminals of a Keithley 2400 high-precision multimeter (which serves as an external excitation power source to provide a precise voltage and current source and can measure it) using silver glue wires, and place it in the atomic force sample chamber;

[0198] The initial position of graphene on molybdenum disulfide was characterized using an atomic force microscope (Cypher ES) from Oxford University. After applying a voltage of 5 V to the molybdenum disulfide channel for 100 s, the positional distribution of graphene on it was characterized again. The graphene moved from one end of the molybdenum disulfide channel to the other end and stopped at the metal electrode, indicating that the length of the molybdenum disulfide channel determines the maximum sliding range of the graphene.

[0199] Comparative Example 1

[0200] 1) This comparative example utilizes a dry transfer method to prepare, as shown in the figure Figure 2 The superlubricated van der Waals heterostructure 100 shown contains a movable two-dimensional material 110 made of hexagonal boron nitride. Three hexagonal boron nitride fragments with thicknesses of 1, 6, and 8 nm were prepared in this comparative example. Figure 7As shown in (a), the conductive two-dimensional material layer 121 is a single layer of graphene with a thickness of 0.34 nm, and its surface roughness is guaranteed to be less than 1 nm; the transition two-dimensional material layer 122 is also made of hexagonal boron nitride with a thickness of 30 nm. This superlubricated van der Waals heterojunction 100 can be referred to as "hexagonal boron nitride / graphene / hexagonal boron nitride heterojunction". Among them, the lattice constant of hexagonal boron nitride is 2.504 Å, and the lattice constant of graphene is 2.46 Å, with a difference of 1.8% between the two.

[0201] 2) Using a Zeiss Sigma 300 field emission electron microscope and a Raith pattern generator, electrode patterns were exposed on graphene. A Quorum 150T Plus high-vacuum ion sputtering system was then used to place the exposed heterojunction within the sputtering chamber. Titanium (3nm thick) and gold (57nm thick) metal targets were selected, and the sputtering was performed at a vacuum of 10... -5 Under the condition of mbar, a sputtering current of 20 mA and a sputtering time of 300 s were used to prepare a first metal electrode 210 and a second metal electrode 220 made of titanium and gold at both ends of graphene. The titanium coating is 3 nm thick and is in direct contact with the graphene. The gold coating is deposited on the titanium coating and has a thickness of 57 nm. Finally, the first metal electrode 210 and the second metal electrode 220 with a metal coating thickness of 60 nm are distributed at both ends of the graphene.

[0202] 3) Connect the first metal electrode 210 and the second metal electrode 220 at both ends of the graphene channel to the positive and negative terminals of a Keithley 2400 high-precision multimeter (which serves as an external excitation power source to provide a precise voltage and current source and can measure it) using silver paste wires, and place them in the atomic force sample chamber.

[0203] 4) The initial positions of hexagonal boron nitride on graphene / boron nitride were characterized using an atomic force microscope (AFM) of Oxford University (model Cypher ES). After applying a pulse voltage of 50 V to the graphene channel for 0.1 s, the positional distribution of hexagonal boron nitride fragments on it was characterized using an electron microscope (EMB) of Zeiss (model Sigma 300). This voltage condition was denoted as 50 V - 0.1 s.

[0204] Figure 7 (a) is the atomic force amplitude image of the hexagonal boron nitride / graphene / hexagonal boron nitride heterojunction in this comparative example before the application of an external 50V-0.1s electrical excitation; Figure 7 (b) is an electron microscope image of the hexagonal boron nitride / graphene / hexagonal boron nitride heterojunction in this comparative example after being electrically excited by an external 50V for 0.1s. Figure 7 (a) and Figure 7(b) It can be seen that the hexagonal boron nitride fragments did not move under this voltage excitation. In addition, attempts were made to increase the external excitation voltage to drive the hexagonal boron nitride fragments, but even when the graphene channel was disconnected (reaching the maximum current density that the graphene channel could withstand), the hexagonal boron nitride fragments did not move.

[0205] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An electrically driven device with super-lubricated interface slippage, characterized in that, include: Superlubricated van der Waals heterojunction (100); A first metal electrode (210) and a second metal electrode (220) are connected to the superlubricated van der Waals heterojunction (100). The superlubricated van der Waals heterojunction (100) includes a two-dimensional material platform (120) and a movable two-dimensional material (110) stacked on the surface of the two-dimensional material platform (120). The two-dimensional material platform (120) includes a conductive two-dimensional material layer (121) on its surface, and the movable two-dimensional material (110) is stacked on the surface of the conductive two-dimensional material layer (121). The surface roughness of the conductive two-dimensional material layer (121) is less than 2 nm, and the lattice constant of the conductive two-dimensional material layer (121) differs from that of the movable two-dimensional material (110) by more than 1.8%. The movable two-dimensional material (110) is selected from one or more of hexagonal boron nitride, graphene, and transition metal compounds; the conductive two-dimensional material layer (121) is selected from one or more of graphene and transition metal compounds. The first metal electrode (210) and the second metal electrode (220) are respectively connected to the conductive two-dimensional material layer (121). When the first metal electrode (210) and the second metal electrode (220) are electrically connected to the external excitation power supply, a current density can be generated on the conductive two-dimensional material layer (121). The current density generated on the conductive two-dimensional material layer (121) is adjusted to be greater than 0.1 mA / μm, so as to realize that the movable two-dimensional material (110) can slide on the surface of the conductive two-dimensional material layer (121) by electric drive.

2. The electrically driven device for ultra-lubricated interface slippage according to claim 1, characterized in that, The thickness of the two-dimensional material platform (120) is 10~200 nm; The thickness of the conductive two-dimensional material layer (121) is 0.3~100 nm.

3. The electrically driven device for ultra-lubricated interface slippage according to claim 2, characterized in that, The two-dimensional material platform (120) further includes a transition two-dimensional material layer (122), which is located below the conductive two-dimensional material layer (121); The material of the transition two-dimensional material layer (122) includes one or more of hexagonal boron nitride, graphene, and transition metal compounds.

4. The electric drive device for super-lubricated interface slippage according to any one of claims 1 to 3, characterized in that, The superlubricated van der Waals heterojunction (100) further includes a substrate (130) which is placed below the two-dimensional material platform (120); The substrate (130) is made of one or more of silicon wafers, sapphire, mica, and polydimethylsiloxane.

5. The electrically driven device for ultra-lubricated interface slippage according to claim 4, characterized in that, The superlubricated van der Waals heterojunction (100) further includes a gate (230) disposed on the substrate (130).

6. A microelectromechanical system drive device, characterized in that, The microelectromechanical system drive device includes the electric drive device for ultra-lubricated interface sliding as described in any one of claims 1 to 5; And an external excitation power supply, which is connected to the first metal electrode (210) and the second metal electrode (220) of the electrically driven device that slides through the super-lubricated interface.

7. A microelectromechanical system, characterized in that, The microelectromechanical system includes the electro-actuated device for ultra-lubricated interface sliding as described in any one of claims 1 to 5; or the microelectromechanical system drive device as described in claim 6.

8. An electrically driven sliding method for a superlubricated interface, characterized in that, Including the following steps: A: Prepare an electric drive device for super-lubricated interface slippage as described in any one of claims 1 to 5, and connect the first metal electrode (210) and the second metal electrode (220) of the electric drive device for super-lubricated interface slippage to an external excitation power supply. B: Adjust the external excitation power supply to make the current density of the conductive two-dimensional material layer (121) greater than 0.1 mA / μm, thereby driving the sliding direction of the movable two-dimensional material (110) on the conductive two-dimensional material layer (121); wherein, The output voltage of the external excitation power supply ranges from 1 to 200 V, and the voltage output time is from 1 μs to 100 s. The angle between the sliding direction of the movable two-dimensional material (110) on the conductive two-dimensional material layer (121) and the current direction is 0° or 180°.

9. The electrically driven sliding method for a superlubricated interface according to claim 8, characterized in that, The electric drive device for ultra-lubricated interface slippage further includes a gate (230). In step B, the range of the gate voltage is adjusted to -100 ~ 100 V.

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