A method for preparing atomically sharp diamond cutting edges

Abstract

The present invention belongs to the field of atomic precision machining and discloses a method for preparing an atomically sharp diamond edge, comprising the following steps: Step 1: determining the geometry of the atomically sharp diamond edge; Step 2: using a femtosecond laser to trim the diamond surface to a specific crystal orientation; Step 3: designing a clamping device for the atomically sharp diamond edge; Step 4: using a focused ion beam to prepare nanometer-sized diamond micropillars and transfer them to the edge clamping device; Step 5: using argon plasma polishing technology to achieve atomic-level flatness on the surface of the diamond nanopillars; Step 6: using X-Nano multi-degree-of-freedom nanomanipulation technology to achieve atomic-level cleavage of the diamond nanopillars; Step 7: using a spherical aberration electron microscope to characterize and verify the atomically sharp diamond edge. The present invention achieves the preparation of an atomically sharp diamond edge with an edge blunt radius through micro-nano machining and atomic-scale controllable cleavage methods.

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] The current state-of-the-art diamond edge blunt radius only reaches 2–9 nm, a significant gap from atomic-level sharpness. Furthermore, from a theoretical perspective, it remains unknown whether atomically sharp diamond edges can be stably achieved. This is because the extremely high surface area resulting from extreme sharpness will generate a large number of dangling chemical bonds. Driven by the enormous surface energy and surface stress, the atomically sharp diamond edge may undergo surface reconstruction, altering the edge geometry and increasing the blunt radius. Therefore, the fabrication of atomically sharp edges is urgently needed. 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 solution of the method for preparing an atomic-level sharp diamond cutting edge of the present invention is as follows:

[0005] A method for preparing an atomically sharp diamond cutting edge comprises the following steps:

[0006] Step 1: Define the geometry of the atomically sharp diamond edge;

[0007] Step 2: Use a femtosecond laser to trim the diamond surface to a specific crystal orientation;

[0008] Step 3: Design a clamping device for the atomically sharp diamond edge;

[0009] Step 4: Nano-sized diamond micropillars are prepared using a focused ion beam and transferred to a cutting edge holding device;

[0010] Step 5: Use argon plasma polishing technology to make the surface of diamond nanopillars flat at the atomic level;

[0011] Step 6: Atomic-scale cleavage of diamond nanopillars using X-Nano multi-degree-of-freedom nanomanipulation technology;

[0012] Step 7: Characterize and verify the atomically sharp diamond edge using spherical aberration electron microscopy.

[0013] Furthermore, the step 1 includes the following steps:

[0014] 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.

[0015] Furthermore, the step 2 includes the following steps:

[0016] First, the corresponding crystal surface is trimmed on the artificial single crystal diamond. It is known that the initial surface of the artificial single crystal diamond is generally {111} surface. <111> Oriented nanoneedle tips can be directly processed on this surface. If tips with other orientations are 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.

[0017] Furthermore, the step 3 includes the following steps:

[0018] The atomically sharp diamond cutting edge is driven by the X-Nano multi-degree-of-freedom in-situ transmission electron microscope sample holder with sub-nanometer displacement control accuracy to achieve atomic precision processing. The atomically sharp diamond cutting edge is placed on a semi-copper mesh that fits the X-Nano sample holder, and the diamond micron sheet and the semi-copper mesh contact finger are welded by melting metal platinum.

[0019] Furthermore, step 4 includes the following steps:

[0020] Using 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 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.

[0021] Furthermore, the step 5 includes the following steps:

[0022] The semi-copper mesh with diamond micropillars 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 nanopillars were polished into diamond nano-needle tips with a diameter of about 50nm and an atomically smooth surface.

[0023] Furthermore, the step 6 includes the following steps:

[0024] A semi-copper mesh with a diamond nanotip was mounted on an X-Nano sample holder. The X-Nano sample holder utilizes a piezoelectric ceramic design based on a stick-slip mechanism, combining sub-nanometer displacement control accuracy with five degrees of freedom and millimeter-scale displacement travel. This allows the diamond nanotip to continuously press against the indenter in a transmission electron microscope, causing instability, bending the diamond nanotip, and ultimately causing cleavage fracture.

[0025] Furthermore, the step 7 includes the following steps:

[0026] 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 rake face of the cutting edge, and the surface is the flank face of the cutting edge. The cutting edge is composed of only a few atoms, and both the front and rear cutting edges are atomically flat.

[0027] 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.

[0028] 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, laying the foundation for the realization and theoretical research of atomic precision processing, and clarifying 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

[0029] Figure 1 Schematic diagram of the present invention for transferring and rough processing diamond using a focused ion beam;

[0030] Figure 2 Schematic diagram of the atomically flat diamond nanotip structure of the present invention;

[0031] Figure 3 Schematic diagram of the bending deformation and cleavage fracture of diamond nanoneedles in a transmission electron microscope according to the present invention;

[0032] Figure 4 Schematic diagram of the present invention for characterizing atomically sharp diamond edges using a spherical aberration-corrected transmission electron microscope;

[0033] Figure 5 Schematic diagram of the preparation of atomically sharp edges of different shapes according to the present invention. DETAILED DESCRIPTION

[0034] 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 cutting edge of the present invention in conjunction with the accompanying drawings.

[0035] The present invention provides a method for preparing an atomic-level sharp diamond cutting edge, comprising the following steps:

[0036] Step 1: Define the geometry of the atomic-level sharp diamond edge: Design the rake angle of the edge according to the different properties of the processed specimen. 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-tip. The negative rake angle edge is used. <111> orientation( <111> It is the crystallographic direction, which means 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.

[0037] 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} plane ({111} is a crystal plane, and the normal direction of this crystal plane is <111> ), if the preparation <111> Oriented nanoneedle tips can be processed directly on this surface. If tips with other orientations 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.

[0038] Step 3: Design a Clamping Device for the Atomically Sharp Diamond Edge: Atomically sharp diamond edges will be machined with atomic precision using an X-Nano multi-degree-of-freedom in-situ transmission electron microscope (TEM) sample holder with sub-nanometer displacement control. The atomically sharp diamond edges will be placed on a semi-copper mesh that fits within the X-Nano sample holder. Melting platinum will weld the diamond micronized blade to the semi-copper mesh contact fingers.

[0039] 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 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. The micron sheet is then transferred to the semi-copper mesh contact finger. Then, a diamond micro-pillar with a height of about 1μm and a diameter of about 200nm is processed on the diamond micron sheet using the focused ion beam. Figure 2As shown in the figure, after being processed by focused ion beam processing and argon plasma polishing, the surface of the diamond nanotip is nearly atomically flat. The diamond nanotip is the precursor of the atomic-level diamond edge.

[0040] Step 5: Use argon plasma polishing technology to make the surface of diamond nanopillars atomically flat: Place the semi-copper mesh with diamond micropillars 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 nanopillars are polished into diamond nanotips with a diameter of about 50nm and an atomically flat surface.

[0041] Step 6: Use X-Nano multi-degree-of-freedom nanomanipulation technology to achieve atomic-level cleavage of diamond nanopillars: Install the half-copper mesh with the diamond nanotip onto the X-Nano sample holder. The X-Nano sample holder adopts a piezoelectric ceramic design based on a stick-slip mechanism, which combines sub-nanometer displacement control accuracy of five degrees of freedom with millimeter-level displacement travel. It can achieve the continuous pressure of the diamond nanotip against the indenter in the transmission electron microscope and cause instability, thus achieving the bending of the diamond nanotip and eventually cleavage 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 the transmission electron microscope. The atomically flat cleavage surface and the atomically flat needle tip surface intersect to form an atomically sharp cutting edge, and the corresponding cleavage surface and surface become the rake and flank faces of the cutting edge, respectively.

[0042] Step 7: Use spherical aberration electron microscopy to characterize and verify the atomic-level sharp diamond edge: Use spherical aberration electron microscopy to characterize the diamond nanotip fracture after cleavage. The cleavage surface and the surface of the nanotip intersect to form an atomic-level sharp edge. The corresponding cleavage surface is the rake face of the edge, and the surface is the flank face of the edge. In the spherical aberration electron microscope, it can be observed that the edge is composed of only a few atoms, and both the front and rear blades are atomically flat. Figure 4 As shown, the atomically sharp diamond edge is characterized by several discrete atoms using spherical aberration-corrected transmission electron microscopy.

[0043] 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.

[0044] It will be understood that the present invention is described by way of some embodiments, and it will be appreciated by 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 to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. A method for preparing an atomic-level sharp diamond edge, characterized in that: The steps include: Step 1: Design the rake angle of the cutting edge according to the different properties of the processed specimen. For hard and brittle specimens, choose a negative rake angle cutting edge, and for plastic and soft specimens, choose a positive rake angle cutting edge. Based on the rake angle of the cutting edge, determine the orientation of the subsequent nano-tip. 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; Step 2: Select an artificial single crystal diamond with an initial surface of {111} face. If <111> The oriented nanotip is directly processed on the initial surface. If the tip is prepared with other orientations, 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 100nm. Step 3: Design a clamping device for the atomically sharp diamond edge; Step 4: Processing a diamond micron sheet on the diamond surface obtained in step 2 using focused ion beam micro-nano processing technology, transferring the diamond micron sheet to the clamping device; and then continuing to process a diamond micro-pillar on the diamond micron sheet using the focused ion beam; Step 5: placing the clamping device with the diamond micropillars in an ion thinning instrument, and polishing the diamond micropillars using argon plasma, and finally polishing the diamond micropillars into diamond nanoneedle tips with atomically smooth surfaces; Step 6: Mounting the clamping device with the diamond nanotip onto the X-Nano multi-degree-of-freedom in-situ transmission electron microscope sample holder. The sample holder has five degrees of freedom, sub-nanometer displacement control accuracy, and millimeter-scale displacement travel. The diamond nanotip is controlled to continuously press against the indenter in the transmission electron microscope, causing instability, bending the diamond nanotip, and ultimately cleavage fracture. 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 edge according to claim 1, characterized in that: The diamond micron sheet in step 4 has a thickness of about 1 μm, a height of about 3 μm, and a length of about 5 μm. The diamond microcolumn has a height of about 1 μm and a diameter of about 200 nm.

3. The method for preparing an atomic-level sharp diamond cutting edge according to claim 1, characterized in that: In step 3, the clamping device is a half-copper mesh adapted to the X-Nano sample rod, and the diamond micron sheet and the half-copper mesh contact finger are welded by melting metal platinum.

4. The method for preparing an atomic-level sharp diamond edge according to claim 3, characterized in that: The step 5 comprises the following steps: The semi-copper mesh with diamond micropillars was placed in an ion thinning instrument. The diamond micropillars were polished using argon plasma at a voltage of 0.8kV for 8 hours. Finally, the diamond micropillars were polished into diamond nanoneedle tips with a diameter of about 50nm and an atomically flat surface.

5. The method for preparing an atomic-level sharp diamond 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 rake face of the cutting edge, and the surface is the flank face of the cutting edge. The cutting edge is composed of only a few atoms, and both the front and rear cutting edges are atomically flat.

6. 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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