A method for processing an atomic-level edge structure of a van der waals layered material based on a vibration-assisted probe

Abstract

The application discloses a method for processing atom-level edge structure of van der Waals layered material based on vibration auxiliary probe, which comprises the following steps: step 1, mechanically exfoliating the van der Waals layered material and transferring it to a silicon oxide substrate, and fixing the silicon oxide substrate on a sample table of a one-dimensional normal piezoelectric ceramic actuator through vacuum grease adsorption; step 2, during the processing, a normal load is applied to an atomic force microscope probe, the one-dimensional normal piezoelectric ceramic drives the van der Waals layered material to vibrate in the vertical direction under the driving of a sine signal, and the atomic force microscope probe synchronously performs a feeding and scribing motion, and the processing of the atom-level edge structure is completed through the high-frequency intermittent contact between the atomic force microscope probe and the van der Waals layered material. The application changes the removal state of the probe processing van der Waals layered material through the intermittent contact between the probe and the sample material, improves the material removal efficiency, and significantly improves the processing quality of the atom-level edge structure.

Description

Technical Field

[0001] This invention belongs to the field of micro-nano fabrication technology and relates to a method for preparing edge nanostructures of van der Waals layered materials, specifically a method for fabricating atomic-level edge structures of van der Waals layered materials based on vibration-assisted probes. Background Technology

[0002] The atomic-level edge structures of van der Waals layered materials possess unsaturated bonds and abundant localized states, residing near the Fermi level. These edge regions exhibit strong charge transfer and chemisorption interactions with gas molecules, making them a preferred material for gas sensor fabrication. Compared to the basal surface, the edge regions significantly enhance the adsorption / desorption rates of gas molecules and strengthen the device's response amplitude and detection limit, thus demonstrating unique advantages in low-concentration gas detection and selective recognition. Therefore, the controllable fabrication of van der Waals layered material edge nanostructures is crucial.

[0003] Currently, methods for preparing atomic-level edge structures of van der Waals layered materials with exposed edges mainly include chemical vapor deposition (CVD), template-assisted synthesis (TAMS), and plasma processing and chemical etching (PET). However, these methods suffer from drawbacks such as complex preparation processes, poor controllability of structural dimensions, and stringent environmental requirements. Furthermore, due to the high reactivity of some van der Waals layered materials, traditional edge preparation methods can exacerbate the chemical activity, leading to structural and functional degradation. AFM probe scribing can be performed in an atmospheric environment, offering the advantage of not requiring strict environmental conditions. It does not require a mask during processing and can be used as a standalone process for direct writing of the desired nanostructures, making it well-suited for patterning. It has already been applied to scribing typical van der Waals layered materials. However, due to limitations in processing methods, current probe methods still cannot achieve edge structure processing with good edge consistency on single-layer or few-layer van der Waals layered materials. Moreover, in terms of processing efficiency and precision, it is still difficult to meet the demands of the gas sensing field for efficient and high-precision processing of van der Waals layered materials. Summary of the Invention

[0004] This invention provides a method for processing atomic-level edge structures of van der Waals layered materials based on a vibration-assisted probe. The method uses a commercial atomic force microscope system and a one-dimensional piezoelectric ceramic actuator as processing devices. The piezoelectric ceramic actuator drives the sample to vibrate at high frequency in the vertical direction under the drive of a sinusoidal signal, while the atomic force microscope probe synchronously performs a feeding and scribing motion to complete the processing. Through high-frequency intermittent contact between the probe and the sample, the processing quality of the atomic-level edge structures is effectively improved.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for fabricating atomic-level edge structures of van der Waals layered materials based on vibration-assisted probes includes the following steps:

[0007] Step 1: Mechanically peel off the van der Waals layered material and transfer it to the silica substrate. Then, fix the silica substrate onto the sample stage of the one-dimensional normal piezoelectric ceramic actuator using vacuum grease adsorption.

[0008] Step 2: During the processing, a normal load is applied to the atomic force microscope probe. Under the drive of a sinusoidal signal, the one-dimensional normal piezoelectric ceramic drives the van der Waals layered material to vibrate at high frequency in the vertical direction. The atomic force microscope probe synchronously performs a feeding and scribing motion. Through the high-frequency intermittent contact between the atomic force microscope probe and the van der Waals layered material, the processing of the atomic-level edge structure of the van der Waals layered material is completed.

[0009] Compared with the prior art, the present invention has the following advantages:

[0010] This invention alters the removal state of van der Waals layered materials processed by the probe through intermittent contact between the probe and the sample material, thereby significantly improving the processing quality of atomic-level edge structures while increasing material removal efficiency. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of vibration-assisted probe processing;

[0012] Figure 2 To drive the piezoelectric ceramic sinusoidal signal;

[0013] Figure 3 Scanning electron microscope images of the probe used for processing, (a) top view, (b) side view;

[0014] Figure 4 To create InSe topography using traditional AFM probes;

[0015] Figure 5 To etch InSe cross-sectional patterns using a conventional AFM probe;

[0016] Figure 6 Vibration-assisted AFM probe was used to etch InSe morphology images;

[0017] Figure 7 To etch an InSe cross-section using a vibration-assisted AFM probe. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0019] This invention provides a method for fabricating atomic-level edge structures of van der Waals layered materials using a vibration-assisted probe, the method comprising the following steps:

[0020] Step 1: Fix the silica substrate with mechanically exfoliated van der Waals layered material onto the sample stage of the one-dimensional normal piezoelectric ceramic actuator using vacuum grease adsorption. Set the driving voltage of the one-dimensional normal piezoelectric ceramic actuator to 5~10V and the driving frequency to 150~160kHz.

[0021] Step 2: During the processing, a normal load of 10~20μN is applied to the atomic force microscope probe. Under the drive of a sinusoidal signal, the one-dimensional normal piezoelectric ceramic drives the van der Waals layered material to vibrate at high frequency in the vertical direction. The atomic force microscope probe synchronously performs a feeding and scribing motion. Through the high-frequency intermittent contact between the atomic force microscope probe and the van der Waals layered material, the processing process of the atomic-level edge structure of the van der Waals layered material is completed. The processing depth is controlled to be 2~5nm, and the driving frequency of the sinusoidal signal is set to 150~160kHz.

[0022] Example:

[0023] This embodiment provides a method for obtaining high-quality atomic-level edge structures by using a vibration-assisted probe to scribing van der Waals layered materials. The specific implementation steps of the method are as follows:

[0024] (1) such as Figure 1 As shown, the vibration-assisted AFM probe scribing system mainly consists of a commercial atomic force microscope system and a one-dimensional normal piezoelectric ceramic actuator. During the processing, the piezoelectric ceramic... Figure 2 Driven by the sinusoidal signal shown, it vibrates at high frequency in the vertical direction, where the driving frequency of the sinusoidal signal is set to 155KHz.

[0025] (2) The probe used for processing was the Adama NM-RC diamond probe, with a tip radius of approximately 10 nm. The top and side views of the probe are shown below. Figure 3 As shown in (a) and (b), the stiffness coefficient of the probe cantilever is 350 N / m, and its natural resonant frequency is 750 kHz. Since the vibration frequency of the piezoelectric ceramic is far from the natural vibration frequency of the probe cantilever, the probe cantilever will not undergo elastic deformation due to the vibration of the piezoelectric ceramic during processing, thus ensuring high-frequency intermittent contact between the probe and the sample.

[0026] (3) Typical van der Waals layered material InSe is prepared by mechanical exfoliation, with silicon oxide as the substrate, and the thickness obtained by exfoliation is about 50 nm. The silicon oxide substrate is fixed on the sample stage of the piezoelectric ceramic actuator by vacuum grease adsorption to ensure that the vibration is not attenuated.

[0027] (4) The normal load applied by the processing probe is 15μN. The driving voltage and driving frequency of the piezoelectric ceramic are set to 5V and 155kHz, respectively. The vibration amplitude of the piezoelectric ceramic under this driving signal is about 5nm.

[0028] Figure 4 and Figure 5 To obtain morphological and cross-sectional images of the structure from InSe using traditional static scribing with an AFM probe, Figure 4 and Figure 5 It is known that the scribing process is unstable. In the initial stage, the sample is scratched but no obvious scratches are produced. Only some accumulation occurs at the edge of the scribing trajectory, so it is impossible to obtain a high-quality atomic-level edge structure.

[0029] Figure 6 and Figure 7 To obtain morphological and cross-sectional views of the InSe structure by vibration-assisted AFM probe scribing, Figure 6 It can be seen that this processing method can obtain high-quality atomic-level edge structures, from Figure 7 It can be seen that the depth of the etched structure is approximately 4 nm.

[0030] Therefore, compared with traditional static scribing, vibration-assisted probe scribing of van der Waals layered materials can improve the processing quality and help obtain atomic-level edge structures.

Claims

1. A method for processing an atomic-scale edge structure of a van der Waals layered material based on a vibration-assisted probe, characterized by The method includes the following steps: Step 1: Mechanically peel off the van der Waals layered material and transfer it to the silica substrate. Then, fix the silica substrate onto the sample stage of the one-dimensional normal piezoelectric ceramic actuator using vacuum grease adsorption. Step 2: During the processing, a normal load is applied to the atomic force microscope probe. Under the drive of a sinusoidal signal, the one-dimensional normal piezoelectric ceramic drives the van der Waals layered material to vibrate at high frequency in the vertical direction. The atomic force microscope probe synchronously performs a feeding and scribing motion. Through the high-frequency intermittent contact between the atomic force microscope probe and the van der Waals layered material, the processing of the atomic-level edge structure of the van der Waals layered material is completed.

2. The method for fabricating atomic-level edge structures of van der Waals layered materials based on vibration-assisted probes according to claim 1, characterized in that... In step 1, the driving voltage of the one-dimensional normal piezoelectric ceramic actuator is set to 5~10V and the driving frequency is set to 150~160kHz.

3. The method for fabricating atomic-level edge structures of van der Waals layered materials based on vibration-assisted probes according to claim 1, characterized in that... In step 2, the normal load is 10~20μN.

4. The method for fabricating atomic-level edge structures of van der Waals layered materials based on a vibration-assisted probe according to claim 1, characterized in that... In step 2, the processing depth is controlled to be 2~5nm.

5. The method for fabricating atomic-level edge structures of van der Waals layered materials based on a vibration-assisted probe according to claim 1, characterized in that... In step 2, the driving frequency of the sine wave signal is set to 150~160kHz.

6. The method for fabricating atomic-level edge structures of van der Waals layered materials based on a vibration-assisted probe according to claim 1, characterized in that... In step 2, the atomic force microscope probe is a diamond probe.

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