CN115480077B - Atomic force microscope control method for cooperative work of non-contact mode and contact mode - Google Patents

Abstract

An atomic force microscope control method for cooperative work of a non-contact mode and a contact mode solves the problem that the existing two working mode combination modes cannot be characterized in situ, and belongs to the atomic force microscope technology. The cantilever beam of the atomic force microscope drives the probe to be above the sample, and the method comprises the following steps: s1, a cantilever beam of an atomic force microscope drives a probe to be at a set distance above a sample, an excitation sensor excites the cantilever beam to drive the probe to resonate, and long-range performance is tested; s2, the excitation sensor stops excitation, the sample is driven to move upwards or the probe is driven to move downwards so that the surface of the sample is closely attached to the probe above the sample, the excitation sensor generates an excitation signal to act on the sample and/or the probe, and the physicochemical characteristics of the sample are tested; s3, the excitation sensor stops generating an excitation signal, and simultaneously the sample or the probe returns to the original position, and the sample or the probe is driven to move so that the cantilever beam of the atomic force microscope drives the probe to move to the next test position point, and the S1 is shifted.

Description

Atomic force microscope control method with cooperative operation of non-contact mode and contact mode

Technical Field

The invention relates to an atomic force microscope control method for cooperative working of a non-contact mode and a contact mode, belonging to the atomic force microscope technology.

Background Art

Atomic force microscope is an important equipment for characterizing the surface of nanoscale materials. It is widely used in materials, chemistry, biology, medicine, semiconductors and other fields. Atomic force microscope is mainly divided into contact mode and non-contact mode according to its working mode. Among them, contact mode is the most typical static mode. During the scanning process, the probe is close to the surface of the sample, and the attractive or repulsive force will directly act on the cantilever beam, thereby realizing the measurement of the physical and chemical properties of the surface. The non-contact mode can be divided into amplitude modulation mode, frequency modulation mode, force modulation mode, high-order harmonic modulation mode and dissipative signal mode, etc. according to the different types of physical signals used.

Contact mode is the simplest way for atomic force microscopy to obtain the surface morphology of a sample. The Z-axis scanner ensures that the deflection of the cantilever on the sample surface remains unchanged, and the morphology signal is also generated according to its position signal. Conductive atomic force microscopy, piezoelectric force microscopy, and stress-strain testing technology in contact mode have become indispensable and important characterization technologies in the field of scanning probe microscopy.

In the non-contact mode, the tip of the probe never contacts the surface of the sample. The probe resonates within a certain distance from the sample surface. The physical signal of the sensor resonance corresponds to the distance between the sample and the probe. The parameters are brought into a specific physical model to obtain the corresponding physical properties. This method can protect the sample surface from damage by the probe to the greatest extent, while having extremely high morphological resolution.

Atomic force microscopes can achieve excellent performance characterization in any single working mode, contact mode or non-contact mode, but how to effectively combine the two working modes still faces many challenges. The current method is to first perform non-contact mode to obtain the corresponding physical properties of all test positions on the sample surface. After the probe returns to the starting test position, it contacts the sample again and performs contact mode testing in the order of each test position in the non-contact mode to continue to obtain other physical properties of the sample and complete the sample surface characteristic test; for the same test position, two modes of scanning will cause drift, and the secondary scanning or the intervention of multiple external devices cannot determine the multi-field performance characterization of a fixed test position in space. Therefore, the existing combination of the two working modes has the problem that it is inevitable that the in-situ characterization cannot be performed due to mechanical operation and other reasons in space, and it will also cause the problem of not having instantaneous characterization of various physical and chemical properties in time, so that it cannot objectively reflect the true relationship between the interactions between various physical fields at the same time.

Summary of the invention

In view of the problem that the existing combination of the two working modes cannot be characterized in situ and cannot objectively reflect the true relationship between the interactions between the physical fields at the same time, the present invention provides an atomic force microscope control method that cooperates with the contact mode and the non-contact mode.

The present invention provides a control method for an atomic force microscope in which a non-contact mode and a contact mode work in coordination, wherein a cantilever beam of the atomic force microscope drives a probe above a sample, and the method comprises:

S1. The cantilever of the atomic force microscope drives the probe to a set distance above the sample, and the exciting sensor excites the cantilever to drive the probe to resonate to test the long-range performance. It can also switch from one non-contact mode to another non-contact mode to excite the sensor in another non-contact mode to test the long-range performance.

S2. The excitation sensor stops exciting, driving the sample to move upward or the probe to move downward so that the sample surface is close to the probe above. The excitation sensor generates an excitation signal to act on the sample and/or the probe to test the physical and chemical properties of the sample. It is also possible to switch from one contact mode to another contact mode, so that the excitation sensor of another contact mode generates an excitation signal to test the physical and chemical properties of the sample.

S3, the excitation sensor stops generating the excitation signal, and the sample or probe returns to its original position, driving the sample or probe to move so that the cantilever beam of the atomic force microscope drives the probe to move to the next test position point, and then goes to S1.

The present invention can also be in contact mode first and then in non-contact mode, specifically including:

S1. The cantilever beam of the atomic force microscope drives the probe to a set distance above the sample, drives the sample to move upward or the probe to move downward so that the sample surface is close to the probe above, and the excitation sensor generates an excitation signal to act on the sample and/or the probe to test the physical and chemical properties of the sample; it can also switch from one contact mode to another contact mode, so that the excitation sensor of another contact mode generates an excitation signal to test the physical and chemical properties of the sample.

S2. The excitation sensor stops generating excitation signals, and the sample or probe returns to its original position. The excitation sensor excites the cantilever beam to drive the probe to resonate and test the long-range performance. It can also switch from one non-contact mode to another non-contact mode to excite another non-contact mode sensor and image the sample surface.

S3, the excitation sensor stops exciting, drives the sample or probe to move so that the cantilever beam of the atomic force microscope drives the probe to move to the next test position point, and then goes to S1.

Preferably, the physicochemical properties include the sample's morphology, mechanical properties, thermal properties, electrical properties, optical properties, magnetic properties, piezoelectric properties, and electrochemical properties.

Preferably, the excitation signal includes an electrical signal, a magnetic signal, a thermal signal, an optical signal and a mechanical signal.

Preferably, the testing of long-range performance includes: imaging of sample morphology, magnetic field force imaging and electrostatic force imaging.

The beneficial effects of the present invention are as follows: the present invention adopts an in-situ rapid switching method to adjust the vertical distance between the probe and the sample at the same position point to successively realize in-situ measurement of short-range and long-range performances, so that the atomic force microscope can use the contact mode to measure the physical and chemical properties of the sample while scanning in the non-contact mode. The present invention has instantaneous characterization of various physical and chemical properties, and the obtained test performance can objectively reflect the true relationship of the interaction between various physical fields at the same time. The present invention can solve the problem of incompatibility between the non-contact mode and the contact mode of the atomic force microscope.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the signal timing of a time-sharing excitation control system;

FIG2 is a schematic diagram of the hardware structure of an atomic force microscope for testing performance according to a first specific embodiment of the present invention, wherein 1 represents the position of the probe in a non-contact mode, 2 represents the position of the probe in a contact mode; 3 represents a sample; and 4 represents a piezoelectric scanning tube;

Figure 3 is a real-time signal of switching between non-contact mode, contact mode and non-contact mode in Example 1. Signal 1 is a real-time position signal of the cantilever beam driven by the time-sharing excitation control system, and signal 2 is a current signal of contact conduction between the probe and the sample;

FIG4 is a diagram showing the stress-strain relationship between the probe and the sample in Example 2;

FIG5 is a morphology diagram of the HOPG sample scanned by atomic force microscopy in Example 3;

FIG. 6 is a current diagram of the HOPG sample scanned by an atomic force microscope in Example 3.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

The control method of an atomic force microscope in which the non-contact mode and the contact mode work in coordination in the present application, wherein the cantilever beam of the atomic force microscope drives the probe above the sample, comprises:

Step 1, the cantilever beam of the atomic force microscope drives the probe to a set distance above the sample, and the excitation sensor excites the cantilever beam to drive the probe to resonate, and the long-range performance is tested;

Step 2: The excitation sensor stops exciting, drives the sample to move upward or the probe to move downward so that the sample surface is close to the probe above, and the excitation sensor generates an excitation signal to act on the sample and/or the probe to test the physical and chemical properties of the sample;

Step 3: The excitation sensor stops generating the excitation signal, and the sample or probe returns to its original position. The sample or probe is driven to move so that the cantilever beam of the atomic force microscope drives the probe to move to the next test position, and then the process goes to step 1.

In the present application, when testing the same test position point, a time-sharing excitation control method is used to first perform a non-contact mode test, then a contact mode test, and then move to the next test position point to perform a non-contact mode test. At the same test position point, the vertical distance between the probe and the sample is adjusted to successively achieve in-situ measurement of long-range and short-range performances, so that the atomic force microscope can use the contact mode to measure the physical and chemical properties of the sample while scanning in the non-contact mode. Since the present embodiment performs the acquisition and performance characterization of non-contact mode and contact mode parameters at a determined test position point, it can ensure that the force, heat, electricity, light, magnetism and other properties of the sample itself at the same test position point can be truly characterized. The present embodiment can realize the combined application of the two scanning technologies of non-contact mode and contact mode, thereby solving the problem of incompatibility between non-contact mode and contact mode.

In the present application, when testing the same test position point, a time-sharing excitation control method can be used to first perform a contact mode test, then a non-contact mode test, and then move to the next test position point to perform a contact mode test. At the same test position point, the vertical distance between the probe and the sample is adjusted to sequentially achieve in-situ measurement of process and remote performance, allowing the atomic force microscope to measure the physical and chemical properties of the sample using a non-contact mode while scanning in contact mode.

The switching of the operating mode in the present application includes switching from non-contact mode to contact mode, switching from contact mode to non-contact mode, and also includes switching from non-contact mode to another non-contact mode or from contact mode to another contact mode. The combined application of the two scanning technologies of non-contact mode and contact mode is any permutation and combination of any number of non-contact modes and any number of contact modes. For example, non-contact mode-contact mode-non-contact mode-non-contact mode, or contact mode-contact mode-non-contact mode-non-contact mode-contact mode, and so on. After assigning specific functions to the atomic force microscope operating mode, the specific switching scheme is illustrated by example: imaging mode (non-contact mode)-conductive force mode (contact mode)-electrostatic force mode (non-contact mode)-imaging mode (non-contact mode).

The physicochemical properties in this application include the morphology, mechanical properties, thermal properties, electrical properties, optical properties, magnetic properties, piezoelectric properties, and electrochemical properties of the sample.

In the present application, the excitation signal includes electrical signal, magnetic signal, thermal signal, optical signal and mechanical signal.

The long-range performance testing in this application includes: imaging of sample morphology, magnetic field force imaging, and electrostatic force imaging.

Specific implementation method one:

The hardware structure of this embodiment is shown in FIG2 . The cantilever beam of the atomic force microscope drives the probe above the sample 3, and the sample 3 is placed on the piezoelectric scanning tube 4. The hardware structure of this embodiment also includes an excitation sensor for exciting the cantilever beam to drive the probe to resonate, a position sensor for driving the piezoelectric scanning tube to move upward, an excitation sensor in contact mode, an excitation sensor in non-contact mode, and a sensor for driving the piezoelectric scanning tube to move horizontally.

The specific control process includes: first, the parameters to be set are transmitted to the time-sharing excitation control system through the host computer, and the time-sharing excitation control system is loaded into the corresponding sensor through the corresponding signal generation and digital-to-analog conversion. At the same time, the hardware structure transmits the feedback signal back to the time-sharing excitation control system through the analog-to-digital conversion module during operation, and then realizes the time-sharing cooperative excitation technology of non-contact mode and contact mode under the control of control methods such as phase-locked loop and negative feedback.

When the working mode is set to non-contact mode-contact mode-non-contact mode, the time-sharing excitation control system acts on the hardware structure through the excitation signal sent by each sensor after digital-to-analog conversion. Taking Figure 2 as an example, when the atomic force microscope is in the non-contact mode, the cantilever beam drives the probe to maintain a certain distance from the sample 3 at position 1, and the excitation sensor excites the cantilever beam to resonate, and the negative feedback loop is coordinated to keep the probe and the sample in a non-contact state. The feedback parameter signal can be set to various physical parameters such as frequency, amplitude, phase, current, etc. according to the specific physical and chemical properties to be characterized. The amplitude modulation mode atomic force microscope realizes imaging of the sample surface and uses the non-contact mode to characterize the long-range performance of the sample, such as: sample morphology imaging, magnetic field force imaging and electrostatic force imaging; after completing the above-mentioned non-contact mode operation steps, when the atomic force microscope is switched to the contact mode, the piezoelectric scanning tube 4 is displaced by the driving signal of the position signal sensor to move the sample upward, so that the cantilever beam drives the probe to be in position 2 to contact with the sample 3, so that the excitation sensor can perform corresponding contact mode characterization on the sample 3. At this time, the negative feedback loop with amplitude as the set parameter is in a closed state;

Finally, after completing the test task in the contact mode, when the atomic force microscope switches to the non-contact mode, the piezoelectric scanning tube 4 will produce a reverse displacement, moving the sample 3 downward and returning to its original position, so that the cantilever beam returns to position 1 away from the sample 3 to maintain the non-contact mode. At this time, the negative feedback loop will be reopened to maintain the dynamic non-contact state between the probe and the sample.

In the above working mode, it is assumed that the additional determined performance is characterized by conductive performance. When the clock signal reaches the switching moment set by the time-sharing excitation control system, the excitation signal used to drive the cantilever beam to resonate in the non-contact mode is immediately turned off. At this time, the system drives the piezoelectric scanning tube forward to make the probe contact the sample, so an obvious current signal can be seen. When the current signal test is completed, the atomic force microscope switches to the non-contact mode, the probe leaves the sample surface to make the current disappear, and the excitation sensor excitation signal is restored to excite the cantilever beam to maintain the resonant state. At the two mode switching points, the changes in the excitation signal and the current signal can be clearly corresponded.

The signal timing diagram of the time-sharing excitation control system is shown in FIG1 . The atomic force microscope operates in the non-contact mode before time t ₀ , the excitation sensor excitation signal is turned off at time t ₀ , and the position sensor sends a driving signal to the piezoelectric scanning tube 4 to drive the sample to move upward, so that the probe and the sample are in contact state, and the excitation sensor applies an additional excitation signal to the probe and/or the sample to start the detection of specific parameters. After completing the relevant detection instructions of the contact mode, the excitation sensor excitation signal is reopened at time t ₁ , and the driving signal of the position sensor is adjusted to the piezoelectric scanning tube 4. The piezoelectric scanning tube 4 drives the sample to move downward, so that the sample surface returns to its original position, and the excitation sensor excitation signal in the contact mode is turned off. That is, the atomic force microscope completes the switch from the non-contact mode to the contact mode at time t ₀ , maintains the contact state during the period from t ₀ to t ₁ , and then returns to the non-contact mode at time t ₁ .

Specific implementation method 2: The difference between the hardware structure of this implementation method and that of FIG2 is that the sample is fixed, the cantilever beam of the atomic force microscope drives the probe above the sample 3, the piezoelectric scanning tube is fixed to the cantilever beam, and the cantilever beam drives the probe to move vertically and horizontally above the sample 3 by driving the piezoelectric scanning tube. The sensors in the hardware structure include an excitation sensor for exciting the cantilever beam to drive the probe to resonate, a position sensor for driving the piezoelectric scanning tube to move downward, an excitation sensor in contact mode, an excitation sensor in non-contact mode, and a sensor for driving the piezoelectric scanning tube to move horizontally;

The specific process includes: first, the parameters to be set are transmitted to the time-sharing excitation control system through the host computer, and the time-sharing excitation control system is loaded into the corresponding sensor through the corresponding signal generation and digital-to-analog conversion. At the same time, the hardware structure transmits the feedback signal back to the time-sharing excitation control system through the analog-to-digital conversion module during operation, and then realizes the time-sharing cooperative excitation technology of non-contact mode and contact mode under the control of control methods such as phase-locked loop and negative feedback.

When the working mode is set to non-contact mode-contact mode-non-contact mode, the time-sharing excitation control system acts on the hardware structure through the excitation signal sent by each sensor after digital-to-analog conversion. When the atomic force microscope is in the non-contact mode, the cantilever beam drives the probe to maintain a certain distance from the sample, the excitation sensor excites the cantilever beam to resonate, and the negative feedback loop is coordinated to keep the probe and the sample in a non-contact state. The feedback parameter signal can be set to various physical parameters such as frequency, amplitude, phase, current, etc. according to the specific physical and chemical properties to be characterized. The amplitude modulation mode atomic force microscope realizes imaging of the sample surface and uses the non-contact mode to characterize the long-range performance of the sample, such as: sample morphology imaging, magnetic field force imaging and electrostatic force imaging; after completing the above non-contact mode operation steps, when the atomic force microscope is switched to the contact mode, the piezoelectric scanning tube is displaced by the driving signal of the position signal sensor so that the cantilever beam drives the probe to move downward, so that the probe contacts the sample, so that the excitation sensor can perform corresponding contact mode characterization on the sample. At this time, the negative feedback loop with amplitude as the set parameter is in a closed state;

Finally, after completing the test task in the contact mode, when the atomic force microscope switches to the non-contact mode, the piezoelectric scanning tube 4 will produce a reverse displacement, causing the cantilever beam to return to position 1 away from the sample 3 and back to its original position, thereby maintaining the non-contact mode operation. At this time, the negative feedback loop will be reopened to maintain the dynamic non-contact state between the probe and the sample.

The signal timing of the time-sharing excitation control system is the same as that of FIG1 . The atomic force microscope operates in non-contact mode before time t ₀ , and the excitation sensor excitation signal is turned off at time t _0. At the same time, the position sensor sends a driving signal to the piezoelectric scanning tube 4 to make the probe move downward and be in contact with the sample. The excitation sensor is used to apply an additional excitation signal to the probe and/or the sample to start the detection of specific parameters. After completing the relevant detection instructions of the contact mode, the excitation sensor excitation signal is turned on again at time t ₁ , and the driving signal of the position sensor is adjusted to make the probe leave the sample surface and return to its original position, and the excitation sensor excitation signal in the contact mode is turned off. That is, the atomic force microscope completes the switch from non-contact mode to contact mode at time t ₀ , maintains the contact state during the period from t ₀ to t ₁ , and then returns to non-contact mode at time t _1. Specific embodiments are given below:

Embodiment 1:

The atomic force microscope performs a design scheme of switching between non-contact mode, contact mode, and non-contact mode at a test position on the HOPG sample. The morphology of the sample is characterized in the non-contact mode, and the conductivity of the sample is characterized in the contact mode.

As shown in FIG3 , signal 1 is the real-time position signal of the cantilever beam when the position sensor is controlled by the time-sharing excitation control system to send a driving signal, and signal 2 is the current signal of the conductive contact between the probe and the sample.

The front end of signal 1 corresponds to the vibration signal of the cantilever beam maintaining the resonant state in the non-contact mode. At t=0, the piezoelectric scanning tube drives the cantilever beam to press down the sample surface. At this time, the amplitude of signal 1 is greatly reduced, that is, the resonance actively excited by the probe in the contact mode stops. In addition, the horizontal position of signal 1 shifts upward and the voltage increases, reflecting the change in the Z-axis position of the piezoelectric scanning tube. At t=0, an obvious contact current is generated between the probe and the sample, and the signal strength is 40 millivolts.

After collecting the contact current between the probe and the sample for about 3 milliseconds, the system executes the switch command from contact mode to non-contact mode. At this time, the initial position of the voltage drop in the Z axis of the piezoelectric scanning tube makes the probe away from the surface of the HOPG sample, and the excitation signal of the excitation sensor starts to maintain the resonant state of the cantilever beam again. At the same time, the contact current signal disappears.

At this point, the command for measuring the contact current at a test position by switching between the non-contact mode-contact mode-non-contact mode has been executed, which takes about 4 milliseconds.

Embodiment 2:

The atomic force microscope performs a design scheme of switching between non-contact mode, contact mode, and non-contact mode at a test position on the HOPG sample. The morphology of the sample is characterized in the non-contact mode, and the stress-strain properties of the sample are characterized in the contact mode.

The switching steps of non-contact mode-contact mode-non-contact mode are basically the same as those in the above-mentioned embodiment 1, except that when switching to the contact mode, the performance characterization function turned on is the stress-strain test.

As shown in Figure 4, the curve composed of square data points is the contact stress curve when the probe and sample switch from non-contact state to contact state, and the curve composed of circular data points is the desorption stress curve when the probe and sample switch from contact state to non-contact state. According to international practice, the contact stress curve is symmetrically processed about the Y axis at zero point in the figure to facilitate the observation and comparison of the two stress-strain curves in the figure at the same time.

After the system switches to contact mode, the piezoelectric scanning tube pushes the sample and the probe closer and closer. As shown in the contact stress curve in Figure 4, when the distance between the sample and the probe moves within 3 nanometers, a maximum attraction of about 8 Newtons will be generated between the two. When the distance between the sample and the probe is less than 2.5 nanometers, the repulsive force begins to increase significantly. When the distance is 2 nanometers, the repulsive force and attractive force between the probe and the sample reach a balanced state. After that, as the probe continues to approach the sample, a maximum repulsive force of about 50 Newtons can be generated between the two.

When the system switches to non-contact mode, the piezoelectric scanning tube drives the sample away from the probe. At this time, the repulsive force between the probe and the sample gradually decreases. Observing the desorption stress curve, it can be seen that since the probe presses into the sample, a maximum attraction of 18 Newtons is generated during desorption, which is significantly greater than the maximum attraction during contact. In addition, during the desorption stage, the gravitational repulsion balance point and gravitational starting point between the sample and the probe move backward by about 2 nanometers and 7 nanometers, respectively.

Embodiment 3:

The atomic force microscope performs a design scheme of switching between non-contact mode, contact mode, and non-contact mode on a 1 micron by 1 micron area on the HOPG sample. The morphology of the sample is characterized in the non-contact mode, and the conductivity of the sample is characterized in the contact mode.

This embodiment is a collection of the single test position point operations in Embodiment 1 performed at the X-axis 512 by Y-axis 512 points in the scanning area, and the control commands at each test position point are the same as the commands in Embodiment 1. In addition, it is necessary to set the basic parameters of the scanning probe microscope, namely, the scanning position, the number of scanning points, the scanning speed, the scanning slope, etc.

Figure 5 is a morphology image of a specific area of the HOPG sample scanned by an atomic force microscope, and Figure 6 is a contact current image of the same area of the HOPG sample scanned by an atomic force microscope. Comparing the two images, it can be seen that the morphology image of the sample and the contact current image have an accurate correspondence, and the size of the contact current between the sample and the probe corresponding to the ups and downs of the morphology also has size changes that conform to the morphology law.

This proves that the collaborative working technology of the non-contact mode and contact mode of the present application can indeed realize the multi-field coupled in-situ characterization of materials, solving the problem that the morphology image and the current image cannot accurately correspond due to the intrinsic defects of the mechanical equipment in the traditional secondary scanning technology.

Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims (9)

1. The atomic force microscope control method for cooperative work of a non-contact mode and a contact mode is characterized in that a cantilever beam of the atomic force microscope drives a probe to be above a sample, and the method comprises the following steps:

S1, a cantilever beam of an atomic force microscope drives a probe to be at a set distance above a sample, an excitation sensor excites the cantilever beam to drive the probe to resonate, and long-range performance is tested; the testing long range performance includes: imaging the appearance of the sample, magnetic field force imaging and electrostatic force imaging;

S2, the excitation sensor stops excitation, the sample is driven to move upwards or the probe is driven to move downwards so that the surface of the sample is closely attached to the probe above the sample, the excitation sensor generates an excitation signal to act on the sample and/or the probe, and the physicochemical characteristics of the sample are tested;

S3, the excitation sensor stops generating an excitation signal, and simultaneously the sample or the probe returns to the original position, and the sample or the probe is driven to move so that the cantilever beam of the atomic force microscope drives the probe to move to the next test position point, and the S1 is shifted.

2. The method according to claim 1, wherein S1 further comprises switching from one non-contact mode to another non-contact mode, and exciting the other non-contact mode sensor to test long-range performance.

3. The method for controlling an atomic force microscope according to claim 1 or 2, wherein the step S2 further comprises switching from one contact mode to another contact mode, and the excitation sensor of the other contact mode generates an excitation signal to test the physicochemical properties of the sample.

4. The atomic force microscope control method for cooperative work of a non-contact mode and a contact mode is characterized in that a cantilever beam of the atomic force microscope drives a probe to be above a sample, and the method comprises the following steps:

S1, a cantilever beam of an atomic force microscope drives a probe to be at a set distance above a sample, the sample is driven to move upwards or the probe is driven to move downwards so as to enable the surface of the sample to be closely attached to the probe above, an excitation sensor generates an excitation signal to act on the sample and/or the probe, and the physicochemical characteristics of the sample are tested;

S2, the excitation sensor stops generating excitation signals, and simultaneously the sample or the probe returns to the original position, the excitation sensor excites the cantilever beam to drive the probe to resonate, and the long-range performance is tested; the testing long range performance includes: imaging the appearance of the sample, magnetic field force imaging and electrostatic force imaging;

S3, the excitation sensor stops excitation, the sample or the probe is driven to move, so that the cantilever beam of the atomic force microscope drives the probe to move to the next test position point, and S1 is carried out.

5. The method according to claim 4, wherein S1 further comprises switching from one contact mode to another contact mode, and wherein the excitation sensor of the other contact mode generates an excitation signal to test the physicochemical property of the sample.

6. The method according to claim 4 or 5, wherein S2 further comprises switching from one non-contact mode to another non-contact mode, exciting another non-contact mode sensor, and imaging the surface of the sample.

7. The method for controlling an atomic force microscope according to claim 1 or 4, wherein the step S2 and the step S3 are performed by driving the sample motion or the probe motion by using a piezoelectric ceramic device.

8. The method of claim 1 or 4, wherein the physicochemical properties include morphology, mechanical properties, thermal properties, electrical properties, optical properties, magnetic properties, piezoelectric properties, and electrochemical properties of the sample.

9. The method of claim 1 or 4, wherein the excitation signal comprises an electrical signal, a magnetic signal, a thermal signal, an optical signal, and a mechanical signal.