Preparation method of atomic-scale sharp diamond cutting edge

Abstract

The invention belongs to the field of atomic precision machining, and discloses a preparation method of an atomic-scale sharp diamond cutting edge, which comprises the following steps: step 1, determining the geometrical shape of the atomic-scale sharp diamond cutting edge; 2, finishing a diamond surface with specific crystal orientation by using femtosecond laser; 3, designing a clamping device of the atomic-scale sharp diamond cutting edge; 4, preparing a nano-sized diamond micro-column by using a focused ion beam, and transferring the nano-sized diamond micro-column to a cutting edge clamping device; 5, the argon plasma polishing technology is used for enabling the surface of the diamond nanorod to reach atomic level flatness; step 6, atomic-scale cleavage of the diamond nanorod is realized by using an X-Nano multi-degree-of-freedom nano manipulation technology; and 7, representing and verifying the atomic-scale sharp diamond cutting edge by using a spherical aberration electron microscope. The sharp diamond cutting edge with the cutting edge blunt circle radius reaching the atomic scale is prepared through a micro-nano machining and atomic scale controllable cleavage method.

Description

Technical Field

[0001] The invention belongs to the field of atomic precision processing, and in particular relates to a method for preparing an atomic-level sharp diamond cutting edge. Background Art

[0002] At present, the blunt radius of the highest level of diamond cutting edge is only 2~9 nm, which is still far from the sharpness at the atomic level. In addition, from a theoretical point of view, it is still unknown whether the atomic-level sharp diamond cutting edge can exist stably. This is because the extremely high specific surface area brought by the extremely high sharpness will produce a large number of dangling chemical bonds. Driven by the huge surface energy and surface stress, the atomic-level sharp diamond cutting edge may undergo surface reconstruction, which will change the cutting edge geometry and increase the blunt radius. Therefore, it is urgent to realize the preparation of atomic-level sharp cutting edges. Summary of the invention

[0003] The present invention aims to provide a method for preparing an atomic-level sharp diamond cutting edge to solve the above-mentioned technical problems.

[0004] In order to solve the above technical problems, the specific technical scheme of the method for preparing an atomic-level sharp diamond cutting edge of the present invention is as follows: A method for preparing an atomic-level sharp diamond edge comprises the following steps: Step 1: Define the geometry of the atomically sharp diamond edge; Step 2: Use femtosecond laser to trim the diamond surface with a specific crystal orientation; Step 3: Design a clamping device for the atomically sharp diamond edge; Step 4: Prepare nano-sized diamond micropillars using a focused ion beam and transfer them to a cutting edge holding device; Step 5: Use argon plasma polishing technology to make the surface of diamond nanorods atomically flat; Step 6: Use X-Nano multi-degree-of-freedom nanomanipulation technology to achieve atomic-level cleavage of diamond nanorods; Step 7: Characterize and verify the atomically sharp diamond edge using spherical aberration electron microscopy.

[0005] Furthermore, the step 1 comprises the following steps: The rake angle of the cutting edge is designed according to the different properties of the processed specimens. For hard and brittle specimens, a negative rake angle cutting edge is selected, and for plastic and soft specimens, a positive rake angle cutting edge is selected. Based on the rake angle of the cutting edge, the orientation of the subsequent nano-needle tip is determined. The negative rake angle cutting edge is used <111> Oriented needle tip as precursor, positive rake edge used <110> and <100> The oriented needle tip serves as a precursor.

[0006] Furthermore, the step 2 comprises the following steps: First, the corresponding crystal plane is trimmed on the artificial single crystal diamond. It is known that the initial surface of artificial single crystal diamond is generally {111} plane. <111> Oriented nanoneedle tips can be directly processed on the surface. If other oriented tips are to be prepared, a femtosecond laser is used to process a new surface with the corresponding orientation relative to the initial {111} surface, and the surface roughness is required to be within 100 nm.

[0007] Furthermore, the step 3 comprises the following steps: The atomically sharp diamond edge is driven by the X-Nano multi-degree-of-freedom in-situ transmission electron microscope sample rod with sub-nanometer displacement control accuracy to achieve atomic precision processing. The atomically sharp diamond edge is placed on a semi-copper mesh adapted to the X-Nano sample rod, and the diamond micron sheet and the semi-copper mesh contact finger are welded by melting metal platinum.

[0008] Furthermore, step 4 includes the following steps: Using focused ion beam micro-nano processing technology, firstly, a diamond micron sheet with a thickness of about 1μm, a height of about 3μm, and a length of about 5μm is processed on the diamond surface after femtosecond laser trimming, and then the micron sheet is transferred to the semi-copper mesh contact finger; then, a diamond microcolumn with a height of about 1μm and a diameter of about 200nm is processed on the diamond micron sheet through the focused ion beam.

[0009] Furthermore, the step 5 comprises the following steps: The semi-copper mesh with diamond micro-columns was placed in an ion thinning instrument, and the nano-needle tip was polished using argon plasma at a voltage of 0.8kV for 8 hours. Finally, the diamond nano-columns were polished into diamond nano-needle tips with a diameter of about 50nm and an atomically smooth surface.

[0010] Further, the step 6 comprises the following steps: The semi-copper mesh with the diamond nano-needle tip is installed on the X-Nano sample rod. The X-Nano sample rod adopts a piezoelectric ceramic design based on a stick-slip mechanism, which has sub-nanometer displacement control accuracy with five degrees of freedom and millimeter-level displacement stroke. It enables the diamond nano-needle tip to continuously press against the pressure head and become unstable in the transmission electron microscope, realizes the bending of the diamond nano-needle tip, and finally causes cleavage fracture.

[0011] Furthermore, the step 7 comprises the following steps: The fracture surface of the diamond nanotip after cleavage fracture was characterized using a spherical aberration electron microscope. The cleavage surface and the surface of the nanotip intersect to form an atomically sharp cutting edge. The corresponding cleavage surface is the front cutting edge, and the surface is the back cutting edge. The cutting edge is composed of only a few atoms, and both the front and rear cutting edges are atomically flat.

[0012] Furthermore, by designing different nanotip orientations and adjusting the angle between the nanotip surface and the cleavage plane, the preparation of atomically sharp edges of different shapes can be achieved.

[0013] The method for preparing an atomic-level sharp diamond edge of the present invention has the following advantages: the present invention realizes the preparation of an atomic-level sharp diamond edge with a blunt radius of the edge through micro-nano processing and atomic-scale controllable cleavage, lays the foundation for the realization and theoretical research of atomic precision processing, and clarifies that an atomic-level sharp diamond edge can exist stably; in addition, the shape of the diamond edge prepared by the present invention is controllable, and edges with different rake angles can be stably produced to meet the atomic precision processing requirements of processed specimens with different mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram of the present invention for transferring and rough processing diamond using a focused ion beam; Figure 2 This is a schematic diagram of the atomically flat diamond nano-tip structure of the present invention; Figure 3 A schematic diagram of the bending deformation and cleavage fracture of a diamond nanoneedle in a transmission electron microscope according to the present invention; Figure 4 A schematic diagram of using a spherical aberration corrected transmission electron microscope to characterize an atomic-level sharp diamond edge according to the present invention; Figure 5 Schematic diagram of the preparation of atomic-level sharp edges of different shapes according to the present invention. DETAILED DESCRIPTION

[0015] In order to better understand the purpose, structure and function of the present invention, the following is a further detailed description of a method for preparing an atomic-level sharp diamond edge of the present invention in conjunction with the accompanying drawings.

[0016] A method for preparing an atomic-level sharp diamond cutting edge of the present invention comprises the following steps: Step 1: Determine the geometry of the atomic-level sharp diamond edge: Design the rake angle of the edge according to the different properties of the processed specimens. For hard and brittle specimens (ceramics, semiconductor materials), choose a negative rake angle edge, and for plastic and soft specimens (metal materials), choose a positive rake angle edge. Based on the rake angle of the edge, determine the orientation of the subsequent nano-needle tip. The negative rake angle edge is used <111> orientation( <111> is the crystallographic direction, which means that the axis of the needle tip is parallel to <111> direction) as the precursor, and the positive rake edge is used <110> and <100> The oriented needle tip serves as a precursor.

[0017] Step 2: Use femtosecond laser to trim the diamond surface with a specific crystal orientation: After determining the orientation of the nanotip, it is necessary to trim the corresponding crystal surface on the synthetic single crystal diamond. It is known that the initial surface of the synthetic single crystal diamond is generally the {111} surface ({111} is a crystal surface, and the normal direction of this crystal surface is <111> ), if the preparation <111> Oriented nanoneedle tips can be directly processed on this surface. If other oriented tips are to be prepared, a femtosecond laser is required to process a new surface with the corresponding orientation relative to the initial {111} surface, and the surface roughness is required to be within 100 nm.

[0018] Step 3: Design a clamping device for atomically sharp diamond edges: Atomic-sharp diamond edges will be processed with atomic precision under the drive of the X-Nano multi-degree-of-freedom in-situ transmission electron microscope sample holder with sub-nanometer displacement control accuracy. The atomically sharp diamond edge will be placed on a semi-copper mesh adapted to the X-Nano sample holder, and the diamond micron sheet and the semi-copper mesh contact finger will be welded by melting metal platinum.

[0019] Step 4: Prepare nano-sized diamond micropillars using a focused ion beam and transfer them to the edge holding device: Figure 1 As shown in the figure, using the focused ion beam micro-nano processing technology, a diamond micron sheet with a thickness of about 1μm, a height of about 3μm, and a length of about 5μm is first processed on the diamond surface after femtosecond laser trimming, and the micron sheet is transferred to the semi-copper mesh contact finger. Then, a diamond micro-column with a height of about 1μm and a diameter of about 200nm is processed on the diamond micron sheet by continuing to use the focused ion beam. Figure 2 As shown, after being processed by focused ion beam processing, argon plasma polishing and other processes, the surface of the diamond nano-needle tip is close to the atomic level. The diamond nano-needle tip is the precursor of the atomic level diamond edge.

[0020] Step 5: Use argon plasma polishing technology to make the surface of the diamond nanocolumns atomically flat: Place the semi-copper mesh with diamond microcolumns in an ion thinning instrument, and use argon plasma to polish the nanotip at a voltage of 0.8kV for 8 hours. Finally, the diamond nanocolumns are polished into diamond nanotip with a diameter of about 50nm and an atomically flat surface.

[0021] Step 6: Use X-Nano multi-degree-of-freedom nanomanipulation technology to achieve atomic-level cleavage of diamond nanopillars: Install the semi-copper mesh with diamond nanotip onto the X-Nano sample rod. The X-Nano sample rod adopts a piezoelectric ceramic design based on a stick-slip mechanism, which has sub-nanometer displacement control accuracy of five degrees of freedom and millimeter-level displacement travel. It can achieve continuous pressure of the diamond nanotip against the pressure head in the transmission electron microscope and cause instability, realize the bending of the diamond nanotip, and finally cause cleavage and fracture. Figure 3 As shown, through multi-degree-of-freedom nanomanipulation technology, the bending deformation and cleavage fracture of the diamond nanoneedle are realized in a transmission electron microscope. The atomically flat cleavage plane and the atomically flat needle tip surface intersect to form an atomically sharp cutting edge, and the corresponding cleavage plane and surface become the rake face and flank face of the cutting edge, respectively.

[0022] Step 7: Characterize and verify the atomic-level sharp diamond edge using spherical aberration electron microscopy: Use spherical aberration electron microscopy to characterize the fracture of the diamond nano-needle tip after cleavage fracture. The cleavage surface and surface of the nano-needle tip intersect to form an atomic-level sharp edge. The corresponding cleavage surface is the front blade surface of the edge, and the surface is the back blade surface of the edge. In the spherical aberration electron microscope, it can be observed that the edge is composed of only a few atoms, and the front and rear blade surfaces are both atomically flat. Figure 4 As shown, the atomically sharp diamond edge is characterized by aberration-corrected transmission electron microscopy and appears as a discrete number of atoms.

[0023] like Figure 5 As shown, by designing different nanotip orientations and adjusting the angle between the nanotip surface (corresponding to the back face of the cutting edge) and the cleavage surface (corresponding to the front face of the cutting edge), the preparation of atomically sharp cutting edges of different shapes can be achieved.

[0024] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A method for preparing an atomic-level sharp diamond edge, characterized in that: The steps include: Step 1: Define the geometry of the atomically sharp diamond edge; Step 2: Use femtosecond laser to trim the diamond surface with a specific crystal orientation; Step 3: Design a clamping device for the atomically sharp diamond edge; Step 4: Prepare nano-sized diamond micropillars using a focused ion beam and transfer them to a cutting edge holding device; Step 5: Use argon plasma polishing technology to make the surface of diamond nanorods atomically flat; Step 6: Use X-Nano multi-degree-of-freedom nanomanipulation technology to achieve atomic-level cleavage of diamond nanorods; Step 7: Characterize and verify the atomically sharp diamond edge using spherical aberration electron microscopy.

2. The method for preparing an atomic-level sharp diamond cutting edge according to claim 1, characterized in that: The step 1 comprises the following steps: The rake angle of the cutting edge is designed according to the different properties of the processed specimens. For hard and brittle specimens, a negative rake angle cutting edge is selected, and for plastic and soft specimens, a positive rake angle cutting edge is selected. Based on the rake angle of the cutting edge, the orientation of the subsequent nano-needle tip is determined. The negative rake angle cutting edge is used <111> Oriented needle tip as precursor, positive rake edge used <110> and <100> The oriented needle tip serves as a precursor.

3. The method for preparing an atomic-level sharp diamond cutting edge according to claim 1, characterized in that: The step 2 comprises the following steps: First, the corresponding crystal plane is trimmed on the artificial single crystal diamond. It is known that the initial surface of artificial single crystal diamond is generally {111} plane. <111> Oriented nanoneedle tips can be directly processed on the surface. If other oriented tips are to be prepared, a femtosecond laser is used to process a new surface with the corresponding orientation relative to the initial {111} surface, and the surface roughness is required to be within 100 nm.

4. The method for preparing an atomic-level sharp diamond cutting edge according to claim 1, characterized in that: The step 3 comprises the following steps: The atomically sharp diamond edge is driven by the X-Nano multi-degree-of-freedom in-situ transmission electron microscope sample rod with sub-nanometer displacement control accuracy to achieve atomic precision processing. The atomically sharp diamond edge is placed on a semi-copper mesh adapted to the X-Nano sample rod, and the diamond micron sheet and the semi-copper mesh contact finger are welded by melting metal platinum.

5. The method for preparing an atomic-level sharp diamond cutting edge according to claim 1, characterized in that: The step 4 comprises the following steps: Using focused ion beam micro-nano processing technology, firstly, a diamond micron sheet with a thickness of about 1μm, a height of about 3μm, and a length of about 5μm is processed on the diamond surface after femtosecond laser trimming, and then the micron sheet is transferred to the semi-copper mesh contact finger; then, a diamond microcolumn with a height of about 1μm and a diameter of about 200nm is processed on the diamond micron sheet through the focused ion beam.

6. The method for preparing an atomic-level sharp diamond cutting edge according to claim 1, characterized in that: The step 5 comprises the following steps: The semi-copper mesh with diamond micro-columns was placed in an ion thinning instrument, and the nano-needle tip was polished using argon plasma at a voltage of 0.8kV for 8 hours. Finally, the diamond nano-columns were polished into diamond nano-needle tips with a diameter of about 50nm and an atomically smooth surface.

7. The method for preparing an atomic-level sharp diamond edge according to claim 1, characterized in that: The step 6 comprises the following steps: The semi-copper mesh with the diamond nano-needle tip is installed on the X-Nano sample rod. The X-Nano sample rod adopts a piezoelectric ceramic design based on a stick-slip mechanism, which has sub-nanometer displacement control accuracy with five degrees of freedom and millimeter-level displacement stroke. It enables the diamond nano-needle tip to continuously press against the pressure head and become unstable in the transmission electron microscope, realizes the bending of the diamond nano-needle tip, and finally causes cleavage fracture.

8. The method for preparing an atomic-level sharp diamond cutting edge according to claim 1, characterized in that: The step 7 comprises the following steps: The fracture surface of the diamond nanotip after cleavage fracture was characterized using a spherical aberration electron microscope. The cleavage surface and the surface of the nanotip intersect to form an atomically sharp cutting edge. The corresponding cleavage surface is the front cutting edge, and the surface is the back cutting edge. The cutting edge is composed of only a few atoms, and both the front and rear cutting edges are atomically flat.

9. The method for preparing an atomic-level sharp diamond edge according to claim 1, characterized in that: By designing different nanotip orientations and adjusting the angle between the nanotip surface and the cleavage plane, the preparation of atomically sharp edges of different shapes can be achieved.

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