Method for measuring potential based on Kelvin probe force microscope and related device

Abstract

The invention provides a Kelvin probe force microscope-based potential measurement method and a related device. A laser output light path of a laser and an original illumination light path of an AFM main body are physically coaxial through a switching interface of a light path coupling assembly; a collimating mirror is additionally arranged at the tail end of an AFM illumination light path to ensure that laser is collimated light and covers a probe-sample contact area, then a photosensitive material sample is fixed to a sample table after being cleaned and dried, then a laser excitation module and a KPFM control unit are started, laser parameters are adjusted in real time, surface potential data are synchronously collected, and the surface potential data are obtained. And generating a time-potential curve or a space potential distribution diagram. Accurate focusing of laser beams, precise in-situ detection of a sample microcell and standardized parameter regulation and control can be realized through optical path physical coaxiality and the collimating mirror, and the problems that a traditional KPFM can only measure the dark-state surface potential of a photosensitive material and no in-situ measurement professional equipment is provided for the photo-generated surface potential under laser irradiation are solved. And meanwhile, the problem of difficulty in externally introducing a light source is solved.

Description

Technical Field

[0001] This application relates to the field of Kelvin probe force microscope measurement technology, specifically to a method and related apparatus for measuring electric potential based on a Kelvin probe force microscope. Background Technology

[0002] Kelvin probe force microscopy (KPFM) is an important working mode of atomic force microscopy (AFM). It measures the surface potential (or work function) of a sample by detecting the electrostatic force between the tip of a conductive probe and the sample surface. With its high spatial resolution at the nanometer or even atomic level, KPFM has become an indispensable tool for studying the electronic properties of material surfaces, interfacial charge transfer, and work function distribution of devices. It is widely used in semiconductor device characterization, materials science, and biological interface research. Traditional KPFM techniques primarily measure the surface potential of samples under dark conditions or constant ambient light conditions.

[0003] Currently, methods for studying the influence of illumination on the photogenerated potential of material surfaces have significant limitations: First, the separation of independent light sources from AFM leads to difficulties in spatial alignment and resolution loss, poor temporal synchronization, and poor light intensity control and uniformity. Second, there is a lack of in-situ dynamic measurement capabilities; separate methods struggle to achieve true in-situ, real-time synchronization of illumination conditions and potential measurements, and some opaque samples cannot be measured. Third, commercial AFM systems have functional limitations: standard commercial AFM / KPFM systems typically lack a highly integrated and controllable built-in laser excitation module specifically designed for precise nanoscale photostimulation and synchronized potential measurement. Therefore, existing technologies are significantly insufficient in achieving high spatial resolution, high temporal accuracy, and low-noise in-situ dynamic measurement of nanoscale surface potential under illumination. Summary of the Invention

[0004] This application provides a method and related apparatus for measuring electric potential based on Kelvin probe force microscope. It can achieve precise focusing of laser beam, precise in-situ detection of sample micro-area and standardized parameter control through optical path physical coaxiality and collimating lens. It solves the problem that traditional KPFM can only measure the surface potential of photosensitive materials in the dark state, while lacking professional equipment for in-situ measurement of photogenerated surface potential under laser irradiation. At the same time, it overcomes the problem of difficulty in introducing external light source.

[0005] A first aspect of this application provides a method for measuring electric potential based on a Kelvin probe force microscope, the method comprising: S1. The laser output optical path of the laser is physically coaxial with the original illumination optical path of the AFM body through the adapter interface of the optical path coupling component. A collimating lens is added at the end of the AFM illumination optical path to ensure that the laser is collimated and covers the probe-sample contact area. S2. After cleaning the surface of the photosensitive material sample to be tested, place it in a drying oven to dry, and then fix the dried sample on the sample stage of the AFM body using conductive silver paste. S3. Simultaneously start the laser excitation module and KPFM control unit through the software control interface of the synchronous control unit, so that the laser irradiates the sample according to the set parameters. At the same time, the KPFM control unit adopts AC (Alternating Current) mode and measures the sample surface potential through the probe. S4. Adjust the laser power, wavelength or modulation mode in real time through the software control interface, and simultaneously collect the surface potential data detected by KPFM to generate time-potential curves or spatial potential distribution maps.

[0006] In one possible implementation, in step S3, before formally starting KPFM detection, the sample is first scanned at a frequency of 2 Hz to predict the quantity at different locations. After determining the appropriate measurement area, the scanning frequency is then adjusted to 0.1 Hz for fine measurement.

[0007] In one possible implementation, in step S4, the laser setting parameters include a wavelength of 660 nm and power adjustment gradients of 0 mW, 9 mW, 18 mW, and 27 mW.

[0008] In one possible implementation, in step S3, the surface potential is calculated using the following formula: in, The surface potential between the material and the probe. Let be the work function of the probe. Let be the work function of the sample.

[0009] A second aspect of this application provides a Kelvin probe force microscope system, comprising: The AFM body includes a probe, a piezoelectric scanner, and an optical detection unit, wherein the optical detection unit is used to monitor the deflection of the probe cantilever beam in real time. The KPFM control unit, which is electrically connected to the AFM body, is used to provide AC modulation voltage and DC (Direct Current) bias feedback control to measure the sample surface potential; The laser excitation module includes a laser source and an optical path coupling component. The optical path coupling component is connected to the original illumination optical path of the AFM body to couple the laser into the AFM illumination optical path, so that the laser optical path and the original illumination optical path of the AFM are physically coaxial, and the laser irradiation area and the KPFM scanning area spatially overlap. A synchronization control unit is electrically connected to the KPFM control unit and the laser excitation module, and includes a hardware synchronization circuit and a software control interface. The hardware synchronization circuit is used to synchronize the laser modulation signal with the AC voltage signal of the KPFM and the feedback loop clock, with a synchronization accuracy of μs. The software control interface is used to adjust the laser parameters in real time and synchronously acquire the surface potential data detected by the KPFM.

[0010] In one possible implementation, the laser optical path first undergoes optical path adaptation and transmission via an optical fiber coupler in the optical path coupling assembly, then the laser beam is introduced into the original illumination optical path of the AFM body, and finally the laser beam is calibrated into a parallel beam by a collimating lens at the end of the original illumination optical path of the AFM body.

[0011] In one possible implementation, the laser spot diameter output by the laser excitation module is ≤1μm, and the KPFM measurement spatial resolution of the AFM body is <1 nm.

[0012] In one possible implementation, the optical path coupling component is detachably connected to the illumination optical path of the AFM body via an adapter interface.

[0013] In one possible implementation, the probe is a conductive probe, and the sample is a photosensitive material, including solar cell materials, photocatalysts, photodetector materials, novel semiconductors, or two-dimensional transition metal chalcogenides, specifically 1T'-MoTe2-2H lateral homojunctions.

[0014] In this example, the laser output path of the laser is first physically coaxial with the original illumination path of the AFM main body through the adapter interface of the optical path coupling component. A collimating lens is added at the end of the AFM illumination path to ensure that the laser is collimated and covers the probe-sample contact area. After cleaning the photosensitive material sample, it is dried at 100 °C for 60 minutes and fixed on the sample stage. Then, the laser excitation module and the KPFM control unit are simultaneously activated through the synchronous control unit to adjust the laser parameters in real time and synchronously collect surface potential data to generate time-potential curves or spatial potential distribution maps. This device and method can achieve precise laser beam focusing, precise in-situ detection of sample micro-areas, and standardized parameter control through physical coaxiality of the optical path and collimating lens. It solves the problem that traditional KPFM can only measure the surface potential of photosensitive materials in the dark state, while lacking professional equipment for in-situ measurement of photogenerated surface potential under laser irradiation. At the same time, it overcomes the difficulty of introducing an external light source.

[0015] A third aspect of this application provides a terminal including a processor, an input device, an output device, and a memory, wherein the processor, input device, output device, and memory are interconnected, wherein the memory is used to store a computer program, the computer program including program instructions, and the processor is configured to invoke the program instructions to execute the steps of the method for measuring electric potential based on a Kelvin probe force microscope as described in the first aspect of this application. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This application provides a schematic flowchart of a method for measuring electric potential using a Kelvin probe force microscope. Figure 2 An optical schematic diagram of a eutectic 1T'-MoTe2-2H lateral homogeneous-heterogeneous junction under laser power irradiation gradually increased from 0 mW to 27 mW is provided for embodiments of this application. Figure 3 This application provides a schematic diagram of the surface potential of a two-dimensional eutectic 1T'-MoTe2-2H lateral homogeneous-heterogeneous junction as the laser power is gradually increased from 0 mW to 27 mW, based on a Kelvin probe force microscope method for measuring potential. Figure 4This application provides a schematic diagram of the overall structure of a Kelvin probe force microscope system. Figure 5 This application provides a schematic diagram of the structure of a terminal. Figure label: AFM main body-1, KPFM control unit-2, laser excitation module-3, synchronization control unit-4. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0020] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0021] To better understand the method and related apparatus for measuring potential based on Kelvin probe force microscopy provided in this application, a brief introduction to the application scenarios of this method and apparatus is given below. Currently, methods for studying the influence of illumination on the photogenerated potential of material surfaces have significant limitations: First, the separation of the independent light source from the AFM leads to difficulties in spatial alignment and resolution loss, poor temporal synchronization, and poor light intensity control and uniformity. Second, there is a lack of in-situ dynamic measurement capabilities; separate methods struggle to achieve true in-situ, real-time synchronization of illumination conditions and potential measurement, and some opaque samples cannot be measured. Third, commercial AFM systems have functional limitations: standard commercial AFM / KPFM systems typically lack a highly integrated and controllable built-in laser excitation module specifically designed for precise nanoscale photostimulation and synchronous potential measurement. Therefore, existing technologies are significantly insufficient in achieving high spatial resolution, high temporal accuracy, and low noise in-situ dynamic measurement of nanoscale surface potential under illumination.

[0022] The method for measuring electric potential based on Kelvin probe force microscopy is applied to the Kelvin probe force microscopy system. Figure 1 A schematic diagram of the overall process for measuring electric potential using a Kelvin probe force microscope is shown. Figure 1 As shown, it includes: S1. The laser output optical path of the laser is physically coaxial with the original illumination optical path of the AFM body through the adapter interface of the optical path coupling component. A collimating lens is added at the end of the AFM illumination optical path to ensure that the laser is collimated and covers the probe-sample contact area, so as to achieve physical coaxiality between the output laser optical path of the laser and the original illumination optical path of the AFM body through the adapter interface of the optical path coupling component.

[0023] The laser source can be an FC-51 laser, with its output connected to the fiber optic coupler in the optical path coupling assembly via an SMA905 interface to achieve initial optical path adaptation. The optical path coupling assembly can be detachably connected to the existing illumination optical path of the AFM main body via the SMA905 interface. After transmission through the fiber optic coupler, the laser beam is incident into the AFM illumination optical path. A collimating lens with a focal length of 10 mm is added to the end of the AFM illumination optical path. By adjusting the axial position of the collimating lens, the diverging laser beam is calibrated into a parallel beam with a diameter of 2 mm. The real-time imaging of the AFM can be observed to confirm that the laser spot completely coincides with the probe-sample contact area.

[0024] S2. After cleaning the surface of the photosensitive material sample to be tested, place it in a drying oven to dry, and then fix the dried sample onto the sample stage of the AFM body using conductive silver paste.

[0025] Among them, the photosensitive material sample is selected as the 1T'-MoTe2-2H lateral heterojunction. First, use tweezers to hold the sample and place it in a beaker filled with anhydrous ethanol, clean it in an ultrasonic cleaning tank for 15 minutes, and then blow it clean with a nitrogen gun to remove the dust and organic impurities adsorbed on the surface. Subsequently, place the sample in an electrothermal constant-temperature drying oven, set the temperature to 100 °C and the heating time to 60 minutes to remove the residual ethanol and moisture on the surface. After drying, wait for the sample to cool naturally to room temperature, paste and fix the sample to the sample carrier with conductive silver paste, and then vacuum-adsorb the carrier with the sample on the AFM sample stage to ensure that the parallelism error between the sample surface and the substrate plane is ≤0.5°, avoiding measurement errors caused by sample tilt.

[0026] S3. Simultaneously start the laser excitation module and the KPFM control unit through the software control interface of the synchronization control unit, make the laser irradiate the sample according to the set parameters, and at the same time the KPFM control unit adopts the AC mode to measure the surface potential of the sample through the probe.

[0027] Among them, the software of the synchronization control unit can be selected as LabVIEW or MATLAB for control. Through the software control interface of the synchronization control unit, the signal generator supporting the laser excitation module can be called to output a modulation signal to regulate the laser parameters. At the same time, with the help of the time acquisition device of the data acquisition card, the feedback can be synchronously collected to realize the real-time adjustment of the laser power, wavelength or modulation mode.

[0028] Among them, before officially starting the KPFM detection, first perform a pre-measurement on different positions of the sample at a scanning frequency of 2 Hz. After determining a suitable measurement area, then adjust the scanning frequency to 0.1 Hz for fine measurement. Specifically, open the control software of the synchronization control unit, select the KPFM control unit and the laser excitation module respectively in the device connection module of the software interface, establish a communication connection through the USB 3.0 interface, and the hardware synchronization circuit automatically locks the laser modulation signal with the AC voltage signal and the feedback loop clock of the KPFM. The synchronization accuracy is detected and confirmed by an oscilloscope to reach ±50 μs. Specifically, first set the scanning frequency to 2 Hz and the scanning range to 5×5 μm in the software, perform a rapid pre-measurement on the sample surface, and determine a 1×1μm area without obvious defects as the target measurement area through the real-time displayed surface topography map; subsequently, adjust the scanning frequency to 0.1 Hz, the KPFM control unit switches to the AC mode, select a conductive probe of the ASYELEC-01-R2 model, and start measuring the surface potential of the sample.

[0029] KPFM's AC mode is a technique that measures potential difference by vibrating a probe at a certain frequency above the sample surface. Its core principle is to calculate the potential difference by analyzing changes in the amplitude and phase of the probe's vibration, making it suitable for measuring the surface potential of conductors and semiconductors. KPFM's DC mode is a technique that characterizes the surface potential distribution of a material by measuring the contact potential difference between the probe and the sample. The formula for calculating the surface potential is as follows: in, The surface potential between the material and the probe. Let be the work function of the probe. Let be the work function of the sample.

[0030] S4. Adjust the laser power, wavelength or modulation mode in real time through the software control interface, and simultaneously collect the surface potential data detected by KPFM to generate time-potential curves or spatial potential distribution maps.

[0031] The laser's settings include a wavelength of 660 nm and power adjustment gradients of 0 mW, 9 mW, 18 mW, and 27 mW. A preheating time of 300 seconds is set for each power level to ensure laser quality. The software sends parameter adjustment commands to the laser excitation module via an RS232 interface, simultaneously triggering the KPFM control unit to synchronously acquire surface potential data at a sampling rate of 1 kHz. The data is stored in real-time in CSV format (containing three fields: timestamp, laser power, and surface potential value). At each power level, the system automatically generates a time-potential curve (horizontal axis: time, vertical axis: surface potential, unit: mV), and after scanning, plots a spatial potential distribution map of a 1×1 μm area (using pseudo-color encoding, potential range: -100 mV to +100 mV). All charts can be viewed in real-time through the software's data visualization module or exported as PNG format for viewing.

[0032] Figure 2 This diagram illustrates the optical properties of a eutectic 1T'-MoTe2-2H lateral homogeneous junction under laser power irradiation gradually increased from 0 mW to 27 mW. Figure 3 This is a schematic diagram of the surface potential of a two-dimensional eutectic 1T'-MoTe2-2H transverse homogeneous heterojunction under laser power gradually increased from 0 mW to 27 mW.

[0033] The formula for calculating electric potential can be modified to obtain the following formula: in, for electric potential, for The potential difference between 2H-MoTe2 and 1T'-MoTe2 can be calculated using this transformation formula. This example compares the surface potential distribution of the 1T'-MoTe2-2H homojunction under four conditions: white light irradiation and laser irradiation of different powers. Figure 3 As shown, the surface potential of the 1T'-MoTe2 region is approximately 25 mV, significantly higher than that of the 2H-MoTe2 region (approximately 0 mV), with a potential difference of approximately 25 mV between them. When the optical power increases to 9 mW, 18 mW, and 27 mW, respectively, the surface potential of the 1T'-MoTe2-2H film decreases significantly due to the generation of a large amount of photogenerated charge. Compared to the state without laser irradiation, the surface potentials of these two regions decrease by 15 mV, 25 mV, and 35 mV, respectively. However, the potential difference between 1T'-MoTe2 and 2H-MoTe2 remains at approximately 25 mV. Figure 2 As shown, the applied light field can effectively modulate the photogenerated charge on the surface of the 1T'-MoTe2-2H transverse homogeneous-heterogeneous junction, thereby leading to a significant reduction in the overall surface potential of the material. Since photogenerated electrons can easily transfer and do not accumulate near the interface, the potential difference between the two phase interfaces remains essentially stable, revealing an ultrafast cross-interface charge transfer process at the material interface. Under laser irradiation, the 1T'-MoTe2-2H sample exhibits extremely significant photoresponse characteristics.

[0034] In this example, the laser output path of the laser is first physically coaxial with the original illumination path of the AFM main body through the adapter interface of the optical path coupling component. A collimating lens is added at the end of the AFM illumination path to ensure that the laser is collimated and covers the probe-sample contact area. The photosensitive material sample is then cleaned, dried at 100 °C for 60 minutes, and fixed on the sample stage. Subsequently, the laser excitation module and the KPFM control unit are simultaneously activated through the synchronous control unit to adjust the laser parameters in real time and synchronously collect surface potential data, generating a time-potential curve or spatial potential distribution map. This device and method can achieve precise laser beam focusing, precise in-situ detection of sample micro-areas, and standardized parameter control through physical coaxiality of the optical path and the collimating lens. It solves the problem that traditional KPFM can only measure the surface potential of photosensitive materials in the dark state, while lacking professional equipment for in-situ measurement of photogenerated surface potential under laser irradiation. It also overcomes the difficulty of introducing an external light source. For similar results, please refer to [link to relevant documentation]. Figure 4 , Figure 4 This application provides a schematic diagram of the structure of a Kelvin probe force microscope system. For example... Figure 4 As shown, the structure of the Kelvin probe force microscope system includes: The AFM body includes a probe, a piezoelectric scanner, and an optical detection unit, which is used to monitor the deflection of the probe cantilever beam in real time.

[0035] The AFM body can be a commercial atomic force microscope, which includes a conductive probe, a piezoelectric scanner and an optical detection unit. The probe is an ASYELEC-01-R2 conductive probe with a spring constant of 2.8 N / m and a resonant frequency of 75 kHz.

[0036] The KPFM control unit, which is electrically connected to the AFM body, is used to provide AC modulation voltage and DC bias feedback control to measure the sample surface potential.

[0037] The KPFM control unit uses the same brand of KPFM module as the AFM main unit, and is electrically connected to the piezoelectric scanner and optical detection unit of the AFM main unit through the BNC interface.

[0038] The laser excitation module includes a laser source and an optical path coupling component. The optical path coupling component is connected to the original illumination optical path of the AFM body to couple the laser into the AFM illumination optical path, so that the laser optical path and the original illumination optical path of the AFM are physically coaxial, and the laser irradiation area and the KPFM scanning area spatially overlap.

[0039] The FC-51 laser serves as the laser source, and its output end connects to the fiber optic coupler in the optical path coupling assembly via an SMA905 interface, achieving initial optical path adaptation. The optical path coupling assembly can be detachably connected to the existing illumination optical path of the AFM main body via the SMA905 interface. After transmission through the fiber optic coupler, the laser beam is incident into the AFM illumination optical path. A collimating lens with a focal length of 10 mm is added to the end of the AFM illumination optical path. By adjusting the axial position of the collimating lens, the diverging laser beam is calibrated into a parallel beam with a diameter of 2 mm. The complete overlap of the laser spot and the probe-sample contact area can be confirmed by observing the real-time imaging of the AFM.

[0040] The laser excitation module can use an FC-51 laser as the laser source, paired with an optical path coupling assembly consisting of a fiber coupler, collimating lens, and other devices. First, the laser output is connected to the fiber coupler via an SMA905 interface to achieve initial optical path adaptation and low-loss transmission. Then, the output of the fiber coupler is detachably connected to the existing illumination optical path of the AFM main body via an SMA905 interface. The laser beam is transmitted through the fiber coupler and then incident into the AFM illumination optical path. A collimating lens with a focal length of 10 mm is added at the end of the AFM illumination optical path. By adjusting the axial position of the collimating lens, the diverging laser beam is calibrated into a parallel beam with a diameter of 2 mm. Real-time imaging of the AFM can be observed to confirm that the laser spot completely overlaps with the probe-sample contact area. Meanwhile, the optical path coupling component is detachably connected to the illumination optical path of the AFM main body through an adapter interface. Therefore, during installation, it is only necessary to disconnect the original illumination source of the AFM and connect it to the adapter interface to complete the laser coupling. There is no need to make structural modifications to the AFM main body, which is convenient for later maintenance and can be adapted to different models of commercial AFM systems, significantly improving the commercial compatibility of the system.

[0041] A synchronization control unit is electrically connected to the KPFM control unit and the laser excitation module, and includes a hardware synchronization circuit and a software control interface. The hardware synchronization circuit is used to synchronize the laser modulation signal with the AC voltage signal of the KPFM and the feedback loop clock, with a synchronization accuracy of μs. The software control interface is used to adjust the laser parameters in real time and synchronously acquire the surface potential data detected by the KPFM.

[0042] The synchronization control unit, based on an FPGA hardware circuit module, communicates with the KPFM control unit via a USB 3.0 interface and connects to the laser excitation module via an RS232 interface. Its hardware synchronization circuit locks the laser modulation signal with the AC voltage signal and feedback loop clock signal of the KPFM control unit. The synchronization accuracy, as measured by an oscilloscope, reaches the μs level, avoiding the problem of transient response loss caused by asynchrony between illumination and potential measurement. The synchronization control unit is also equipped with a LabVIEW-based software control interface, which can display the laser parameters and the surface potential data detected by the KPFM in real time, and automatically store the collected potential data in CSV format for easy subsequent analysis.

[0043] The following steps can be performed using a Kelvin probe force microscope system: S1. The laser output optical path of the laser is physically coaxial with the original illumination optical path of the AFM body through the adapter interface of the optical path coupling component. A collimating lens is added at the end of the AFM illumination optical path to ensure that the laser is collimated and covers the probe-sample contact area. S2. After cleaning the surface of the photosensitive material sample to be tested, place it in a drying oven to dry, and then fix the dried sample on the sample stage of the AFM body using conductive silver paste. S3. Simultaneously start the laser excitation module and KPFM control unit through the software control interface of the synchronous control unit, so that the laser irradiates the sample according to the set parameters. At the same time, the KPFM control unit adopts AC mode and measures the surface potential of the sample through the probe. S4. Adjust the laser power, wavelength or modulation mode in real time through the software control interface, and simultaneously collect the surface potential data detected by KPFM to generate time-potential curves or spatial potential distribution maps.

[0044] For examples consistent with the above embodiments, please refer to... Figure 5 , Figure 5 A schematic diagram of a terminal structure provided in an embodiment of this application is shown in the figure. It includes a processor, an input device, an output device, and a memory. The processor, input device, output device, and memory are interconnected. The memory is used to store a computer program, which includes program instructions. The processor is configured to call the program instructions. The program includes instructions for performing the following steps. S1. The laser output optical path of the laser is physically coaxial with the original illumination optical path of the AFM body through the adapter interface of the optical path coupling component. A collimating lens is added at the end of the AFM illumination optical path to ensure that the laser is collimated and covers the probe-sample contact area. S2. After cleaning the surface of the photosensitive material sample to be tested, place it in a drying oven to dry, and then fix the dried sample on the sample stage of the AFM body using conductive silver paste. S3. Simultaneously start the laser excitation module and KPFM control unit through the software control interface of the synchronous control unit, so that the laser irradiates the sample according to the set parameters. At the same time, the KPFM control unit adopts AC mode and measures the surface potential of the sample through the probe. S4. Adjust the laser power, wavelength or modulation mode in real time through the software control interface, and simultaneously collect the surface potential data detected by KPFM to generate time-potential curves or spatial potential distribution maps.

[0045] In this example, the laser output path of the laser is first physically coaxial with the original illumination path of the AFM main body through the adapter interface of the optical path coupling component. A collimating lens is added at the end of the AFM illumination path to ensure that the laser is collimated and covers the probe-sample contact area. After cleaning the photosensitive material sample, it is dried at 100 °C for 60 minutes and fixed on the sample stage. Then, the laser excitation module and the KPFM control unit are simultaneously activated through the synchronous control unit to adjust the laser parameters in real time and synchronously collect surface potential data to generate time-potential curves or spatial potential distribution maps. This device and method can achieve precise laser beam focusing, precise in-situ detection of sample micro-areas, and standardized parameter control through physical coaxiality of the optical path and collimating lens. It solves the problem that traditional KPFM can only measure the surface potential of photosensitive materials in the dark state, while lacking professional equipment for in-situ measurement of photogenerated surface potential under laser irradiation. At the same time, it overcomes the difficulty of introducing an external light source.

[0046] The above mainly describes the solutions of the embodiments of this application from the perspective of the method execution process. It is understood that, in order to achieve the above functions, the terminal includes the corresponding hardware structure and / or software modules for executing each function. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments provided herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0047] This application embodiment can divide the terminal into functional units according to the above method example. For example, each function can be divided into a separate functional unit, or two or more functions can be integrated into one processing unit. The integrated unit can be implemented in hardware or as a software functional unit. It should be noted that the unit division in this application embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0048] This application also provides a computer storage medium storing a computer program for electronic data interchange, which causes a computer to perform some or all of the steps of any of the methods described in the above method embodiments for measuring potential using a Kelvin probe force microscope.

[0049] This application also provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program that causes a computer to perform some or all of the steps of any of the methods for measuring potential based on a Kelvin probe force microscope as described in the above method embodiments.

[0050] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0051] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0052] In the several embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical or other forms.

[0053] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0054] Furthermore, the functional units in the various embodiments of the application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software program module.

[0055] If the integrated unit is implemented as a software program module and sold or used as an independent product, it can be stored in a computer-readable storage device (CMD). Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned memory includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0056] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage device, which may include: a flash drive, a read-only memory, a random access memory, a magnetic disk, or an optical disk, etc.

[0057] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for measuring electric potential based on a Kelvin probe force microscope, characterized in that, include: S1. The laser output optical path of the laser is physically coaxial with the original illumination optical path of the AFM body through the adapter interface of the optical path coupling component. A collimating lens is added at the end of the AFM illumination optical path to ensure that the laser is collimated and covers the probe-sample contact area. S2. After cleaning the surface of the photosensitive material sample to be tested, place it in a drying oven to dry, and then fix the dried sample on the sample stage of the AFM body using conductive silver paste. S3. Simultaneously start the laser excitation module and KPFM control unit through the software control interface of the synchronous control unit, so that the laser irradiates the sample according to the set parameters. At the same time, the KPFM control unit adopts AC mode and measures the surface potential of the sample through the probe. S4. Adjust the laser power, wavelength or modulation mode in real time through the software control interface, and simultaneously collect the surface potential data detected by KPFM to generate time-potential curves or spatial potential distribution maps.

2. The method for measuring electric potential based on a Kelvin probe force microscope according to claim 1, characterized in that, In step S3, before officially starting the KPFM detection, the sample is first scanned at a frequency of 2 Hz to predict the amount of the sample at different locations. After determining the appropriate measurement area, the scanning frequency is then adjusted to 0.1 Hz for fine measurement.

3. The method for measuring electric potential based on a Kelvin probe force microscope according to claim 1, characterized in that, In step S4, the laser setting parameters include a wavelength of 660 nm and power adjustment gradients of 0 mW, 9 mW, 18 mW, and 27 mW.

4. The method for measuring electric potential based on a Kelvin probe force microscope according to claim 1, characterized in that, In step S3, the formula for calculating the surface potential is as follows: in, The surface potential between the material and the probe. Let be the work function of the probe. Let be the work function of the sample.

5. A Kelvin probe force microscope system for implementing the method for measuring electric potential based on a Kelvin probe force microscope as described in any one of claims 1 to 4, characterized in that, include: The AFM body includes a probe, a piezoelectric scanner, and an optical detection unit, wherein the optical detection unit is used to monitor the deflection of the probe cantilever beam in real time. The KPFM control unit, which is electrically connected to the AFM body, is used to provide AC modulation voltage and DC bias feedback control to measure the sample surface potential. The laser excitation module includes a laser source and an optical path coupling component. The optical path coupling component is connected to the original illumination optical path of the AFM body to couple the laser into the AFM illumination optical path, so that the laser optical path and the original illumination optical path of the AFM are physically coaxial, and the laser irradiation area and the KPFM scanning area spatially overlap. A synchronization control unit is electrically connected to the KPFM control unit and the laser excitation module, and includes a hardware synchronization circuit and a software control interface. The hardware synchronization circuit is used to synchronize the laser modulation signal with the AC voltage signal of the KPFM and the feedback loop clock, with a synchronization accuracy of μs. The software control interface is used to adjust the laser parameters in real time and synchronously acquire the surface potential data detected by the KPFM.

6. The Kelvin probe force microscope system according to claim 5, characterized in that, The laser optical path first undergoes optical path adaptation and transmission via the fiber optic coupler in the optical path coupling component, then the laser beam is introduced into the original illumination optical path of the AFM body, and finally the laser beam is calibrated into a parallel beam by the collimating lens at the end of the original illumination optical path of the AFM body.

7. The Kelvin probe force microscope system according to claim 5, characterized in that, The laser spot diameter output by the laser excitation module is ≤1 μm, and the KPFM measurement spatial resolution of the AFM body is <1 nm.

8. The Kelvin probe force microscope system according to claim 5, characterized in that, The optical path coupling component is detachably connected to the illumination optical path of the AFM body via an adapter interface.

9. The Kelvin probe force microscope system according to claim 5, characterized in that, The probe is a conductive probe, and the sample is a photosensitive material, including solar cell materials, photocatalysts, photodetector materials, novel semiconductors, or two-dimensional transition metal chalcogenides. Specifically, the two-dimensional transition metal chalcogenide is a 1T'-MoTe2-2H lateral homogeneous heterojunction.

10. A terminal, characterized in that, The device includes a processor, an input device, an output device, and a memory, which are interconnected. The memory stores a computer program, which includes program instructions. The processor is configured to invoke the program instructions to execute the method for measuring electric potential based on a Kelvin probe force microscope as described in any one of claims 1-4.

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