CN113640299B - Microscopic imaging detection method and device for point defect density of two-dimensional material - Google Patents

Abstract

The invention provides a microscopic imaging detection method and a microscopic imaging detection device for the point defect density of a two-dimensional material, wherein the method comprises the following steps: acquiring a differential reflection spectrum of a two-dimensional material to be detected; determining the target wavelength of the monochromatic light according to the differential reflection spectrum; calibrating the defect density of the two-dimensional material to be detected to obtain at least one point defect density; measuring differential reflected light intensity corresponding to the defect density of each point at the target wavelength, and obtaining an empirical formula of the point defect density of the two-dimensional material to be detected according to the differential reflected light intensity and the defect density of each point; calculating to obtain the differential reflection peak intensity of each pixel; and mapping to obtain a point defect density image of the two-dimensional material to be detected based on an empirical formula of the point defect density and the differential reflection peak intensity of each pixel. The invention can effectively avoid the defect of low speed of the traditional scanning imaging method, effectively improves the accuracy of microscopic imaging of the point defect density, and can be used for the large-scale rapid detection of two-dimensional materials.

Description

Microscopic imaging detection method and device for point defect density of two-dimensional materials

technical field

The invention relates to the field of optical technology, in particular to a method and device for microscopic imaging detection of point defect density of two-dimensional materials.

Background technique

Defect density has a significant impact on the physical and chemical properties of two-dimensional materials. Through defect engineering, the properties of two-dimensional materials can be regulated and used for the manufacture of special functional devices. Therefore, defect density detection is an important quality in two-dimensional materials. detection task.

In the related art, the electron microscope imaging method or the property inversion method is used to realize the detection of the defect density. Among them, the electron microscope imaging method uses the electron microscope to directly perform nano-scale high-resolution atomic structure imaging of the two-dimensional material, and selects several representative regions in the atomic structure imaging to count the number of defects. The electron microscope equipment using this method is expensive. High vacuum test conditions are required, and the characterization area is small, so it is not suitable for defect analysis of large-area two-dimensional materials.

The property inversion method is based on the regulation effect of defects on the properties of two-dimensional materials, and the defect density is inversely inferred by measuring the changes in the optical or electrical properties of two-dimensional materials, such as Raman spectroscopy, fluorescence spectroscopy or transient absorption and reflection spectroscopy, etc. In the process of point defect density imaging, the point-by-point scanning method is used to collect the spectrum, and then the spectral features are used to map the point defect density imaging. Rapid detection of 2D materials.

Therefore, the defect density calibration process of two-dimensional materials in the related art is complicated, the imaging cost is high, and the imaging speed is slow, and the problems that it is not suitable for the rapid detection of large-scale two-dimensional materials needs to be solved urgently.

SUMMARY OF THE INVENTION

The invention provides a microscopic imaging detection method and device for point defect density of two-dimensional materials, which is used to solve the problem that the defect density calibration process of two-dimensional materials in the related art is complicated, the imaging cost is high, and the imaging speed is slow, which is not suitable for large The problem of rapid detection of two-dimensional materials at scale.

In a first aspect, the present invention provides a microscopic imaging detection method for point defect density of two-dimensional materials, comprising:

Obtain the differential reflection spectrum of the two-dimensional material to be detected;

determining a target wavelength of monochromatic light for quantifying point defect density according to the differential reflectance spectrum;

Calibrating the defect density of the to-be-detected two-dimensional material to obtain at least one point defect density;

Measure the differential reflected light intensity corresponding to each point defect density at the target wavelength, and perform function fitting according to the differential reflected light intensity and each point defect density to obtain the experience of the point defect density of the two-dimensional material to be detected. formula;

The monochromatic light with the wavelength of the target wavelength is used to illuminate the two-dimensional material to be detected, and the monochromatic light photo of the blank substrate and the monochromatic light photo of the two-dimensional material to be detected are respectively obtained. The color photo and the monochromatic photo of the two-dimensional material to be detected are calculated to obtain the differential reflection peak intensity of each pixel;

Based on the empirical formula of the point defect density and the differential reflection peak intensity of each pixel, a point defect density image of the two-dimensional material to be detected is obtained by mapping.

Optionally, determining the target wavelength of monochromatic light for quantifying point defect density according to the differential reflection spectrum includes:

acquiring the complex refractive index curve of the two-dimensional material to be detected;

determining the peaks and/or troughs of the differential reflectance spectrum;

In the case where the peaks and/or troughs of the differential reflection spectrum correspond to the non-absorbing peak positions of the complex refractive index curve, obtain the wavelengths corresponding to the peaks and/or troughs of the differential reflection spectrum, The wavelength corresponding to the peak and/or trough of the reflection spectrum is taken as the target wavelength.

Optionally, determining the target wavelength of monochromatic light for quantifying point defect density according to the differential reflection spectrum includes:

determining the peaks and/or troughs of the differential reflectance spectrum;

The wavelength corresponding to any peak or trough of the differential reflection spectrum is used as the target wavelength.

Optionally, determining the target wavelength of monochromatic light for quantifying point defect density according to the differential reflection spectrum includes:

The wavelengths corresponding to multiple peaks or valleys of the differential reflection spectrum are selected as the target wavelength.

Optionally, the acquiring the differential reflection spectrum of the two-dimensional material to be detected includes:

respectively acquiring the first reflectivity of the blank substrate and the second reflectivity of the two-dimensional material to be detected;

Based on the first reflectivity and the second reflectivity, formula (1) is used to obtain the differential reflectance spectrum of the two-dimensional material to be detected:

DR=(R _2D -R ₀ )/R ₀ (1)

Wherein, DR represents the differential reflection spectrum of the two-dimensional material to be detected, R _2D represents the second reflectivity, and R ₀ represents the first reflectivity.

Optionally, the measuring the differential reflected light intensity corresponding to each point defect density at the target wavelength includes:

respectively acquiring the third reflectivity of the blank substrate and the fourth reflectivity corresponding to each point defect density of the two-dimensional material to be detected based on the target wavelength;

The differential reflected light intensity corresponding to each point defect density is calculated based on the third reflectivity and the fourth reflectivity.

Optionally, according to the monochromatic light photo of the blank substrate and the monochromatic light photo of the two-dimensional material to be detected, the differential reflection peak intensity of each pixel is calculated and obtained, including:

respectively acquiring the grayscale value of each pixel of the monochromatic light photo of the blank substrate and the grayscale value of each pixel of the monochromatic light photo of the two-dimensional material to be detected;

According to the gray value of each pixel of the monochromatic light photo of the blank substrate and the gray value of each pixel of the monochromatic photo of the two-dimensional material to be detected, each pixel is calculated by using formula (2) The differential reflection peak intensity of :

DR _i =(Img _i '-Img _i )/Img _i (2)

Wherein, DR _i represents the differential reflection peak intensity of the ith pixel, Img _i ′ represents the gray value of the ith pixel of the monochromatic light photo of the two-dimensional material to be detected, and Img _i represents the monochromatic value of the blank substrate. The gray value of the ith pixel of the color photo.

In a second aspect, the present invention provides a microscopic imaging detection device for point defect density of two-dimensional materials, including:

an acquisition unit for acquiring the differential reflection spectrum of the two-dimensional material to be detected;

a determining unit for determining the target wavelength of the monochromatic light for quantifying the density of point defects according to the differential reflection spectrum;

a calibration unit for calibrating the defect density of the two-dimensional material to be detected to obtain at least one point defect density;

The measuring unit is used to measure the differential reflected light intensity corresponding to each point defect density at the target wavelength, and perform function fitting according to the differential reflected light intensity and each point defect density to obtain the two-dimensional material to be detected. Empirical formula for point defect density;

The calculation unit is used for irradiating the two-dimensional material to be detected with the monochromatic light whose wavelength is the target wavelength, and obtains the monochromatic light photo of the blank substrate and the monochromatic light photo of the two-dimensional material to be detected, respectively. The monochromatic light photo of the blank substrate and the monochromatic light photo of the two-dimensional material to be detected are calculated to obtain the differential reflection peak intensity of each pixel;

A mapping unit, configured to map the point defect density image of the two-dimensional material to be detected based on the empirical formula of the point defect density and the differential reflection peak intensity of each pixel.

In a third aspect, the present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, when the processor executes the program, the first aspect or the first aspect is implemented. The second aspect includes the steps of the microscopic imaging detection method for the point defect density of the two-dimensional material.

In a fourth aspect, the present invention also provides a non-transitory computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, realizes the point defect density of the two-dimensional material according to the first aspect or the second aspect The steps of the microscopic imaging detection method.

The microscopic imaging detection method and device for the point defect density of a two-dimensional material provided by the present invention obtains the differential reflection spectrum of the two-dimensional material to be detected, and determines the target wavelength of the monochromatic light for quantifying the point defect density according to the differential reflection spectrum, Calibrate at least one point defect density of the two-dimensional material to be detected, measure the differential reflected light intensity corresponding to each point defect density at the target wavelength, and perform function fitting according to the differential reflected light intensity and each point defect density to obtain the to-be-detected The empirical formula for the point defect density of two-dimensional materials is to use monochromatic light with a wavelength of the target wavelength to illuminate the two-dimensional material to be inspected, and obtain the monochromatic photo of the blank substrate and the monochromatic photo of the two-dimensional material to be inspected, respectively. The monochromatic light photo of the substrate and the monochromatic light photo of the two-dimensional material to be tested are calculated to obtain the differential reflection peak intensity of each pixel. Based on the empirical formula of the point defect density and the differential reflection peak intensity of each pixel, the mapping to obtain the to-be-detected peak intensity The point defect density image of two-dimensional materials, using the target wavelength to quantify the point defect density, the method is simple and effective, and the defect density can be visually imaged under an optical microscope, which can effectively avoid the traditional scanning imaging method. The accuracy of microscopic imaging of point defect density is improved, which can be used for rapid detection of large-scale two-dimensional materials.

Description of drawings

In order to explain the present invention or the technical solutions in the prior art more clearly, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are the For some embodiments of the invention, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

1 is a schematic flowchart of a microscopic imaging detection method for point defect density of two-dimensional materials provided by the present invention;

Fig. 2 is the structural representation of MoS ₂ and base material provided by the present invention;

3 is a schematic diagram of obtaining an optimal wavelength for quantifying MoS ₂ point defect density provided by the present invention;

4 is a schematic diagram of an empirical _formula for calculating the defect density of MoS provided by the present invention;

Fig. 5 is the contrast schematic diagram of the point defect density image of detecting MoS ₂ provided by the present invention;

6 is a schematic structural diagram of a microscopic imaging detection device for point defect density of two-dimensional materials provided by the present invention;

FIG. 7 is a schematic structural diagram of an electronic device provided by the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention. , not all examples. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In order to solve the problem of how to characterize the defect density of a two-dimensional material and visualize the defect density under an optical microscope, an embodiment of the present invention provides a microscopic imaging detection method for the point defect density of a two-dimensional material. A schematic flowchart of a method for microscopic imaging detection of point defect density of a two-dimensional material provided by an embodiment of the present invention. As shown in Figure 1, the method includes the following steps:

Step 100: Obtain a differential reflection spectrum of the two-dimensional material to be detected.

The two-dimensional material to be detected is a two-dimensional material with dielectric properties, such as MoS ₂ , wherein the dielectric properties include complex refractive index.

It should be noted that the embodiment of the present invention is applied to a multilayer structure formed by stacking a two-dimensional material to be detected and a blank substrate, and the differential reflectance spectrum uses the reflectivity of the blank substrate as a reference to calculate the dielectric properties of the two-dimensional material to be detected. The influence on the reflectivity reflects the comprehensive effect of the coherent reflection of incident light by the stack structure of the two-dimensional material to be detected and the blank substrate and the absorption of the incident light by the two-dimensional material to be detected.

The differential reflection spectrum represents a waveform diagram formed between a plurality of wavelengths of the monochromatic light and the differential reflected light intensity corresponding to each wavelength of the monochromatic light.

In one embodiment, the incident light irradiates the two-dimensional material to be detected, and then the differential reflection spectrum of the two-dimensional material to be detected is acquired.

Step 101: Determine the target wavelength of monochromatic light for quantifying the density of point defects according to the differential reflection spectrum.

It should be noted that the change of the dielectric properties of the two-dimensional material to be detected is closely related to the density of point defects, and the differential reflection spectrum can reflect the change process of the dielectric properties. Therefore, the target wavelength of the monochromatic light can be determined according to the differential reflection spectrum, where , the target wavelength of monochromatic light is used to quantify the point defect density.

Optionally, the target wavelength may be one wavelength, or may be multiple different wavelengths.

Step 102 , calibrating the defect density of the two-dimensional material to be detected, to obtain at least one point defect density.

It should be noted that, before calibrating the defect density of the two-dimensional material to be inspected, defects of different densities can be prepared on the surface of the two-dimensional material to be inspected, for example, using a focused ion beam device to bombard the surface of the two-dimensional material to be inspected, Different densities of defects can be obtained.

The defect density represents the number of defects per unit area.

Optionally, the method for calibrating the defect density of the two-dimensional material to be inspected includes a statistical method of electron microscopy.

In one embodiment, different point defects are prepared on the surface of the two-dimensional material to be inspected, and the defect density of the two-dimensional material to be inspected is calibrated by means of electron microscopy statistics to obtain at least one point defect density.

Step 103: Measure the differential reflected light intensity corresponding to each point defect density at the target wavelength, and perform function fitting according to the differential reflected light intensity and each point defect density to obtain the point defects of the two-dimensional material to be detected Empirical formula for density.

The empirical formula for point defect density is used to express the functional relationship between the point defect density of the two-dimensional material and the differential reflected light intensity corresponding to each point defect density at the target wavelength.

In one embodiment, if the target wavelength is one wavelength, the differential reflected light intensity corresponding to each point defect density at one wavelength is measured, and if the target wavelength is multiple wavelengths, the corresponding point defect density at each wavelength is measured. The differential reflected light intensity.

Further, a multivariate function fitting operation is performed according to multiple sets of differential reflected light intensities and point defect densities to obtain an empirical formula for the point defect density of the two-dimensional material to be detected.

Step 104, irradiating the two-dimensional material to be detected with monochromatic light with a wavelength of the target wavelength, respectively obtaining a monochromatic light photo of a blank substrate and a monochromatic light photo of the two-dimensional material to be detected, according to the blank The monochromatic light photo of the substrate and the monochromatic light photo of the two-dimensional material to be detected are calculated to obtain the differential reflection peak intensity of each pixel.

In one embodiment, if the target wavelength is one wavelength, the monochromatic light of the wavelength is used to irradiate the two-dimensional material to be detected, and a set of monochromatic light photos of the blank substrate and the monochromatic light photos of the two-dimensional material to be detected are obtained, According to the monochromatic light photos of the blank substrate and the monochromatic light photos of the two-dimensional material to be detected, the differential reflection peak intensity of each pixel of the two-dimensional material to be detected is calculated.

In one embodiment, if the target wavelength is multiple wavelengths, the monochromatic light of each wavelength is used to irradiate the two-dimensional material to be detected, and multiple sets of monochromatic light photos of the blank substrate and the monochromatic light of the two-dimensional material to be detected are obtained. According to the monochromatic light photo of each group of blank substrates and the monochromatic light photo of the two-dimensional material to be detected, the differential reflection peak intensity of each pixel of the two-dimensional material to be detected is calculated.

Step 105 , based on the empirical formula of the point defect density and the differential reflection peak intensity of each pixel, map to obtain a point defect density image of the two-dimensional material to be detected.

It should be noted that the point defect density image can intuitively reflect the point defect density of each region of the two-dimensional material.

In one embodiment, according to the empirical formula of the point defect density of the two-dimensional material to be detected and the differential reflection peak intensity of each pixel of the two-dimensional material to be detected, the point defect density of each pixel of the two-dimensional material to be detected can be obtained. , according to the point defect density of each pixel of the two-dimensional material to be inspected, a point defect density image of the two-dimensional material to be inspected can be obtained by mapping.

The microscopic imaging detection method of the point defect density of a two-dimensional material provided by the embodiment of the present invention obtains the differential reflection spectrum of the two-dimensional material to be detected, and determines the target wavelength of the monochromatic light for quantifying the point defect density according to the differential reflection spectrum, Calibrate at least one point defect density of the two-dimensional material to be detected, measure the differential reflected light intensity corresponding to each point defect density at the target wavelength, and perform function fitting according to the differential reflected light intensity and each point defect density to obtain the to-be-detected The empirical formula for the point defect density of two-dimensional materials is to use monochromatic light with a wavelength of the target wavelength to illuminate the two-dimensional material to be inspected, and obtain the monochromatic photo of the blank substrate and the monochromatic photo of the two-dimensional material to be inspected, respectively. The monochromatic light photo of the substrate and the monochromatic light photo of the two-dimensional material to be tested are calculated to obtain the differential reflection peak intensity of each pixel. Based on the empirical formula of the point defect density and the differential reflection peak intensity of each pixel, the mapping to obtain the to-be-detected peak intensity The point defect density image of two-dimensional materials, using the target wavelength to quantify the point defect density, the method is simple and effective, and the defect density can be visually imaged under an optical microscope, which can effectively avoid the traditional scanning imaging method. The accuracy of microscopic imaging of point defect density is improved, which can be used for rapid detection of large-scale two-dimensional materials.

Based on the contents of the foregoing embodiments, the determining, according to the differential reflection spectrum, the target wavelength of the monochromatic light for quantifying the density of point defects includes:

acquiring the complex refractive index curve of the two-dimensional material to be detected;

determining the peaks and/or troughs of the differential reflectance spectrum;

In the case where the peaks and/or troughs of the differential reflection spectrum correspond to the non-absorbing peak positions of the complex refractive index curve, obtain the wavelengths corresponding to the peaks and/or troughs of the differential reflection spectrum, The wavelength corresponding to the peak and/or trough of the reflection spectrum is taken as the target wavelength.

其中曲线n表示复折射率实部，曲线k表示复折射率虚部，λ表示波长。The complex refractive index curve is

The curve n represents the real part of the complex refractive index, the curve k represents the imaginary part of the complex refractive index, and λ represents the wavelength.

In one embodiment, the complex refractive index curve of the two-dimensional material to be detected is obtained by measuring with an ellipsometer, or the complex refractive index curve of the two-dimensional material to be detected is obtained by querying a database.

It should be noted that the differential reflectance spectrum reflects the change process of the dielectric properties of the two-dimensional material to be tested, and the change of the dielectric properties of the two-dimensional material to be tested is closely related to the density of point defects. Therefore, it needs to be selected from the differential reflectance spectrum. The peaks and/or valleys that can best reflect the overall dielectric properties of the two-dimensional material to be tested.

Further, the peak of the imaginary part of the complex refractive index curve is an absorption peak. Since the absorption peak of the imaginary part of the complex refractive index is close to the energy band edge, it is easily affected by environmental factors and cannot stably reflect the overall dielectric properties of the two-dimensional material to be detected. Therefore, it is necessary to select the non-absorbing peak position of the imaginary complex refractive index curve corresponding to the peaks and/or troughs of the differential reflection spectrum to effectively reflect the overall dielectric properties of the two-dimensional material to be detected.

In one embodiment, the complex refractive index curve of the two-dimensional material to be detected is obtained by measuring or querying the database by an ellipsometer, the peaks and/or troughs of the differential reflection spectrum are obtained, and the complex refractive index curve of the two-dimensional material to be detected and the differential The peaks and/or troughs of the reflection spectrum, determine that the peaks and/or troughs of the differential reflection spectrum correspond to the non-absorbing peak positions of the imaginary part of the complex refractive index curve, and the peaks and/or troughs of the differential reflection spectrum correspond to the imaginary part of the complex refractive index In the case of the non-absorption peak position of the curve, the wavelength corresponding to the peak and/or the trough of the differential reflection spectrum is obtained, and the wavelength corresponding to the peak and/or the trough of the differential reflection spectrum is used as the target wavelength.

The microscopic imaging detection method of the point defect density of a two-dimensional material provided by the embodiment of the present invention acquires the peaks and/or troughs of the differential reflection spectrum, according to the complex refractive index curve of the two-dimensional material to be detected and the peaks and/or peaks of the differential reflection spectrum The trough, the peak and/or trough of the differential reflection spectrum is determined to correspond to the position of the non-absorption peak of the imaginary part of the complex refractive index curve, and the peak and/or trough of the differential reflection spectrum corresponds to the position of the non-absorption peak of the imaginary part of the complex refractive index curve. In this case, the wavelengths corresponding to the peaks and/or troughs of the differential reflection spectrum are obtained, and the wavelengths corresponding to the peaks and/or troughs of the differential reflection spectrum are used as the target wavelengths, which can reflect the overall dielectric properties of the two-dimensional material to the greatest extent. Furthermore, the point defect density of the two-dimensional material can be quantified to the greatest extent, thereby effectively improving the accuracy of the microscopic imaging of the point defect density.

The process of obtaining the preferred wavelength of MoS ₂ point defect density will be specifically described with reference to FIG. 2 and FIG. 3 . FIG. 2 is a schematic structural diagram of MoS ₂ and a base material provided by an embodiment of the present invention. 3 is a schematic diagram of obtaining an optimal wavelength for quantifying MoS ₂ point defect density according to an embodiment of the present invention.

As shown in FIG. 2 , a single-layer MoS ₂ with a thickness d ₁ is disposed on the upper surface of the silicon oxide wafer substrate, wherein the structure of the silicon oxide wafer substrate includes a single-crystal silicon surface with a thickness d ₃ of 1 mm provided with a thickness d ₂ of 300nm _SiO2 layer, which in turn constitutes a multi-layer thin film stack structure of air-single-layer MoS2 _- silicon oxide wafer substrate.

_In the case where the incident light irradiates the surface of MoS2, the incident light undergoes refraction and reflection process _at the multilayer interface in the multilayer thin film stack structure, and the reflectivity R0 and MoS of the silicon oxide substrate are caused by the interference of the reflected light. The reflectivity R _2D of ₂ fluctuates with the wavelength of the incident light.

In addition, when the incident light irradiates the surface of MoS ₂ , MoS ₂ absorbs the incident light, resulting in partial troughs of R ₀ and R _2D in certain wavelength regions of the incident light.

The differential reflectance spectrum is based on the reflectance R ₀ of the silicon oxide substrate as a reference to calculate the influence of the dielectric properties of the monolayer MoS ₂ on the reflectivity. The combined effect of the coherent reflection of the layer _- thin film stack structure and the absorption of incident light by MoS.

As shown in FIG. 3 , based on the graphs of R ₀ and R _2D , a graph of the differential reflection spectrum DR is obtained. The wavelengths corresponding to the peaks of the DR curve are 500 nm, and the wavelengths corresponding to the troughs of the DR curve are 610 nm and 660 nm, respectively.

其中曲线n表示复折射率实部，曲线k表示复折射率虚部。As shown in Fig. ₃ , the complex refractive index curve of MoS2 is

The curve n represents the real part of the complex refractive index, and the curve k represents the imaginary part of the complex refractive index.

As shown in Figure 3, comparing the curve of the differential reflection spectrum with the complex refractive index curve, it can be concluded that the trough of the differential reflection spectrum corresponds to the two absorption peaks of the imaginary part of the complex refractive index curve, where the The wavelength 610nm corresponding to the trough corresponds to the peak B of the imaginary part of the complex refractive index curve, and the wavelength 660nm corresponding to the trough of the differential reflection spectrum corresponds to the peak A of the imaginary part curve of the complex refractive index. Since these two wavelengths are close to the energy band edge, It is easily affected by environmental factors and cannot stably reflect the dielectric properties of MoS ₂ , while the wavelength of 500 nm corresponding to the peak of the differential reflection spectrum corresponds to the position of the non-absorption peak of the complex refractive index curve, which can effectively reflect the overall dielectric properties of MoS ₂ . electrical properties. Therefore, the wavelength of 500 nm was taken as the optimal wavelength for quantifying the MoS ₂ point defect density in the multilayer thin film stack structure.

Based on the contents of the foregoing embodiments, the determining, according to the differential reflection spectrum, the target wavelength of the monochromatic light for quantifying the density of point defects includes:

determining the peaks and/or troughs of the differential reflectance spectrum;

The wavelength corresponding to any peak or trough of the differential reflection spectrum is used as the target wavelength.

It should be noted that the differential reflection spectrum reflects the change process of the dielectric properties of the two-dimensional material to be detected, and the change of the dielectric properties of the two-dimensional material to be detected is closely related to the density of point defects. Therefore, in the embodiment of the present invention, differential The wavelength corresponding to any peak or trough of the reflection spectrum is used as the target wavelength, and the target wavelength is used to quantify the point defect density of the two-dimensional material to be detected.

In one embodiment, the peaks and/or troughs of the differential reflection spectrum are determined, and the wavelength corresponding to any peak or trough of the differential reflection spectrum is used as a target wavelength, and the target wavelength is used to quantify the point defect density.

The microscopic imaging detection method of the point defect density of a two-dimensional material provided by the embodiment of the present invention determines the peak and/or trough of the differential reflection spectrum, and uses the wavelength corresponding to any peak or trough of the differential reflection spectrum as the target wavelength. The wavelength can reflect the dielectric properties of two-dimensional materials, quantify the point defect density of two-dimensional materials, and then realize the microscopic imaging of point defect density.

Based on the contents of the foregoing embodiments, the determining, according to the differential reflection spectrum, the target wavelength of the monochromatic light for quantifying the density of point defects includes:

The wavelengths corresponding to multiple peaks or valleys of the differential reflection spectrum are selected as the target wavelength.

It should be noted that the differential reflection spectrum reflects the change process of the dielectric properties of the two-dimensional material to be detected, and the change of the dielectric properties of the two-dimensional material to be detected is closely related to the density of point defects. Therefore, in the embodiment of the present invention, differential The wavelengths corresponding to multiple peaks or troughs of the reflection spectrum are used as target wavelengths, and the target wavelengths are used to quantify the point defect density of the two-dimensional material to be detected.

In one embodiment, peaks and/or troughs of the differential reflection spectrum are determined, and wavelengths corresponding to multiple peaks or troughs of the differential reflection spectrum are used as target wavelengths, and each target wavelength is used to quantify the point defect density.

The microscopic imaging detection method of the point defect density of a two-dimensional material provided by the embodiment of the present invention determines the peaks and/or troughs of the differential reflection spectrum, and uses the wavelengths corresponding to the multiple peaks or troughs of the differential reflection spectrum as the target wavelength. The wavelength can reflect the dielectric properties of two-dimensional materials and quantify the point defect density of two-dimensional materials, thereby improving the accuracy of microscopic imaging of point defect density.

Based on the contents of the foregoing embodiments, the acquiring the differential reflection spectrum of the two-dimensional material to be detected includes:

respectively acquiring the first reflectivity of the blank substrate and the second reflectivity of the two-dimensional material to be detected;

Based on the first reflectivity and the second reflectivity, formula (1) is used to obtain the differential reflectance spectrum of the two-dimensional material to be detected:

DR=(R _2D -R ₀ )/R ₀ (1)

Wherein, DR represents the differential reflection spectrum of the two-dimensional material to be detected, R _2D represents the second reflectivity, and R ₀ represents the first reflectivity.

The first reflectivity is the ratio of the reflected light intensity of the blank substrate to the incident light intensity.

The second reflectivity is the ratio of the reflected light intensity of the two-dimensional material to be detected to the incident light intensity.

In one embodiment, the incident light irradiates the blank substrate and the two-dimensional material to be detected, respectively, and the first reflectance of the blank substrate and the second reflectance of the two-dimensional material to be detected at each wavelength of the incident light are measured. The first reflectance and the second reflectance at each wavelength of light are used to obtain the differential reflectance spectrum of the two-dimensional material to be measured.

The microscopic imaging detection method of the point defect density of a two-dimensional material provided by the embodiment of the present invention obtains the first reflectivity of the blank substrate and the second reflectivity of the two-dimensional material to be detected, respectively, based on the first reflectivity and the second reflectivity , the differential reflection spectrum of the two-dimensional material to be detected is calculated, and then the target wavelength that can be used for quantitative defect density detection can be directly selected according to the differential reflection spectrum. The method is simple and effective, and further effectively avoids the traditional scanning imaging method. , which effectively improves the accuracy of microscopic imaging of point defect density and can be used for rapid detection of large-scale two-dimensional materials.

Based on the contents of the foregoing embodiments, the measuring the differential reflected light intensity corresponding to each point defect density at the target wavelength includes:

respectively acquiring the third reflectivity of the blank substrate and the fourth reflectivity corresponding to each point defect density of the two-dimensional material to be detected based on the target wavelength;

The differential reflected light intensity corresponding to each point defect density is calculated based on the third reflectivity and the fourth reflectivity.

The third reflectivity is the ratio of the reflected light intensity of the blank substrate to the incident light intensity.

The fourth reflectivity is the ratio of the reflected light intensity corresponding to each point defect density of the two-dimensional material to be detected to the incident light intensity.

In one embodiment, calculating the differential reflected light intensity corresponding to each point defect density based on the third reflectivity and the fourth reflectivity specifically includes:

Based on the third reflectivity and the fourth reflectivity, formula (3) is used to calculate the differential reflected light intensity corresponding to each point defect density:

DR' _j =(R' _j -R' ₀ )/R' ₀ (3)

Among them, _DR'j represents the differential reflected light intensity corresponding to the jth point defect density, R'j represents the fourth reflectivity corresponding to the _jth point defect density of the two-dimensional material to be tested, and R' ₀ represents the th Three reflectivity.

In one embodiment, the blank substrate and the two-dimensional material to be detected are respectively irradiated with monochromatic light of the target wavelength, and the third reflectivity of the blank substrate and the fourth reflectance corresponding to each point defect density of the two-dimensional material to be detected are measured. Based on the third reflectivity and the fourth reflectivity, the differential reflected light intensity corresponding to each point defect density is calculated.

The microscopic imaging detection method of the point defect density of a two-dimensional material provided by the embodiment of the present invention obtains the third reflectivity of the blank substrate and the fourth reflectivity corresponding to each point defect density of the two-dimensional material to be detected, and based on the third reflectance The differential reflected light intensity corresponding to each point defect density is calculated, and the empirical formula of the defect density of the two-dimensional material can be obtained based on the differential reflected light intensity corresponding to each point defect density.

Based on the content of the above-mentioned embodiment, according to the monochromatic light photo of the blank substrate and the monochromatic light photo of the two-dimensional material to be detected, the differential reflection peak intensity of each pixel is calculated and obtained, including:

respectively acquiring the grayscale value of each pixel of the monochromatic light photo of the blank substrate and the grayscale value of each pixel of the monochromatic light photo of the two-dimensional material to be detected;

According to the gray value of each pixel of the monochromatic light photo of the blank substrate and the gray value of each pixel of the monochromatic photo of the two-dimensional material to be detected, each pixel is calculated by using formula (2) The differential reflection peak intensity of :

DR _i =(Img _i '-Img _i )/Img _i (2)

Wherein, DR _i represents the differential reflection peak intensity of the ith pixel, Img _i ′ represents the gray value of the ith pixel of the monochromatic light photo of the two-dimensional material to be detected, and Img _i represents the monochromatic value of the blank substrate. The gray value of the ith pixel of the color photo.

In one embodiment, according to the monochromatic light photo of the blank substrate and the monochromatic light photo of the two-dimensional material to be detected, the gray value of each pixel of the monochromatic light photo of the blank substrate and the gray value of the two-dimensional material to be detected are obtained respectively. The gray value of each pixel of the monochromatic light photo, and then based on the gray value of each pixel of the monochromatic photo of the blank substrate and the gray value of each pixel of the monochromatic photo of the two-dimensional material to be detected, The differential reflection peak intensity of each pixel is calculated using the formula.

According to the microscopic imaging detection method of the point defect density of a two-dimensional material provided by the embodiment of the present invention, according to the monochromatic light photo of the blank substrate and the monochromatic light photo of the two-dimensional material to be detected, each of the monochromatic light photos of the blank substrate is obtained respectively. The gray value of each pixel and the gray value of each pixel of the monochromatic light photo of the two-dimensional material to be detected are based on the gray value of each pixel of the monochromatic light photo of the blank substrate and the gray value of the two-dimensional material to be detected. The gray value of each pixel of the monochrome photo is calculated by using the formula to obtain the differential reflection peak intensity of each pixel. Based on the empirical formula of the differential reflection peak intensity and point defect density of each pixel, the two to be detected can be quickly mapped. The point defect density image of the dimensional material can realize the intuitive imaging of the defect density under the optical microscope, which can effectively avoid the defects of low rate of the traditional scanning imaging method, and effectively improve the accuracy of the microscopic imaging of the point defect density. For rapid detection of large-scale two-dimensional materials.

The process of mapping to obtain the point defect density image of MoS ₂ is described in detail with reference to FIG. 4 and FIG. 5 . FIG. 4 is a schematic diagram of a curve of an empirical formula for calculating the defect density of MoS ₂ provided by an embodiment of the present invention. FIG. 5 is a schematic diagram of comparison of point defect density images for detecting MoS ₂ provided by an embodiment of the present invention.

As shown in Figure 4, the defect density of MoS ₂ is calibrated to obtain at least one point defect density.

Taking monochromatic light with a wavelength of 500 nm as the incident light of MoS ₂ and the base material, the differential reflected light intensity corresponding to each point defect density of MoS ₂ was measured.

As shown in Figure 4, a two-dimensional rectangular coordinate system is constructed. The abscissa is the differential reflected light intensity, and the ordinate is the defect density. In the two-dimensional rectangular coordinate system, at least one point defect density corresponding to each point defect density is marked respectively. The coordinate point of the differential reflected light intensity, and then the curve of the defect density and the differential reflected light intensity is obtained.

The empirical formula for calculating the defect density of MoS ₂ based on multiple coordinate points is:

where ρ represents the defect density of _MoS2 , and DR represents the differential reflected light intensity corresponding to each point defect density.

As shown in Figure 5, Figure (a) represents the optical micrograph of MoS ₂ , including the area of single-layer MoS ₂ , the area of double-layer MoS ₂ and the area of three-layer MoS ₂ , and the gray value of different areas represents different Layers of MoS ₂ .

Figure (b) shows that the defect density of MoS ₂ is calibrated using the differential reflected light intensity of the Raman spectrum, and the defect density image of MoS 2 is obtained. The region of monolayer MoS2 is divided into ₆ regions, representing 6 regions with different defect densities.

Figure (c) shows a defect density image of MoS ₂ calculated by an embodiment of the present invention using monochromatic light with a wavelength of 500 nm. The region of monolayer MoS2 is divided into ₆ regions, representing 6 regions with different defect densities.

Comparing Figure (c) with Figure (b), it can be seen that the defect densities of the same numbered regions of the region of the monolayer MoS ₂ in Figure (c) and Figure (b) are basically the same. The defect density image of MoS ₂ can be calculated and obtained in the embodiment of the present invention, and the accuracy of the embodiment of the present invention is high.

The microscopic imaging detection device for the point defect density of two-dimensional materials provided by the present invention is described below, the microscopic imaging detection device for the point defect density of two-dimensional materials described below and the microscopic imaging of the point defect density of two-dimensional materials described above are described below. The detection methods can be referred to each other correspondingly.

6 is a schematic structural diagram of a microscopic imaging detection device for point defect density of a two-dimensional material provided by an embodiment of the present invention. As shown in FIG. 6 , the microscopic imaging detection device for point defect density of two-dimensional materials includes: an acquisition unit 600 , a determination unit 610 , a calibration unit 620 , a measurement unit 630 , a calculation unit 640 and a mapping unit 650 , wherein,

an acquisition unit 600, configured to acquire the differential reflection spectrum of the two-dimensional material to be detected;

a determining unit 610, configured to determine the target wavelength of the monochromatic light for quantifying the density of point defects according to the differential reflection spectrum;

A calibration unit 620, configured to calibrate the defect density of the two-dimensional material to be detected to obtain at least one point defect density;

The measuring unit 630 is configured to measure the differential reflected light intensity corresponding to each point defect density at the target wavelength, and perform function fitting according to the differential reflected light intensity and each point defect density to obtain the two-dimensional material to be detected The empirical formula for the point defect density of ;

The computing unit 640 is configured to irradiate the two-dimensional material to be detected with the monochromatic light whose wavelength is the target wavelength, and obtain the monochromatic light photo of the blank substrate and the monochromatic light photo of the two-dimensional material to be detected, respectively, according to the The monochromatic light photo of the blank substrate and the monochromatic light photo of the two-dimensional material to be detected are calculated to obtain the differential reflection peak intensity of each pixel;

The mapping unit 650 is configured to map the point defect density image of the two-dimensional material to be detected based on the empirical formula of the point defect density and the differential reflection peak intensity of each pixel.

The microscopic imaging detection device for the point defect density of a two-dimensional material provided by the embodiment of the present invention obtains the differential reflection spectrum of the two-dimensional material to be detected, and determines the target wavelength of the monochromatic light used for quantifying the point defect density according to the differential reflection spectrum, Calibrate at least one point defect density of the two-dimensional material to be detected, measure the differential reflected light intensity corresponding to each point defect density at the target wavelength, and perform function fitting according to the differential reflected light intensity and each point defect density to obtain the to-be-detected The empirical formula for the point defect density of two-dimensional materials is to use monochromatic light with a wavelength of the target wavelength to illuminate the two-dimensional material to be inspected, and obtain the monochromatic photo of the blank substrate and the monochromatic photo of the two-dimensional material to be inspected, respectively. The monochromatic light photo of the substrate and the monochromatic light photo of the two-dimensional material to be tested are calculated, and the differential reflection peak intensity of each pixel is calculated. Based on the empirical formula of point defect density and the differential reflection peak intensity of each pixel, the map to be tested is obtained. The point defect density image of two-dimensional materials, using the target wavelength to quantify the point defect density, the method is simple and effective, and the defect density can be visually imaged under an optical microscope, which can effectively avoid the low rate defects of the traditional scanning imaging method, effectively The accuracy of microscopic imaging of point defect density is improved, which can be used for rapid detection of large-scale two-dimensional materials.

Optionally, the determining unit 610 is configured to:

acquiring the complex refractive index curve of the two-dimensional material to be detected;

determining the peaks and/or troughs of the differential reflectance spectrum;

In the case where the peaks and/or troughs of the differential reflection spectrum correspond to the non-absorbing peak positions of the complex refractive index curve, obtain the wavelengths corresponding to the peaks and/or troughs of the differential reflection spectrum, The wavelength corresponding to the peak and/or trough of the reflection spectrum is taken as the target wavelength.

Optionally, the determining unit 610 is configured to:

determining the peaks and/or troughs of the differential reflectance spectrum;

The wavelength corresponding to any peak or trough of the differential reflection spectrum is used as the target wavelength.

Optionally, the determining unit 610 is configured to:

The wavelengths corresponding to multiple peaks or valleys of the differential reflection spectrum are selected as the target wavelength.

Optionally, the obtaining unit 600 is specifically configured to:

respectively acquiring the first reflectivity of the blank substrate and the second reflectivity of the two-dimensional material to be detected;

Based on the first reflectivity and the second reflectivity, formula (1) is used to obtain the differential reflectance spectrum of the two-dimensional material to be detected:

DR=(R _2D -R ₀ )/R ₀ (1)

Wherein, DR represents the differential reflection spectrum of the two-dimensional material to be detected, R _2D represents the second reflectivity, and R ₀ represents the first reflectivity.

Optionally, the measuring unit 630 is further configured to:

respectively acquiring the third reflectivity of the blank substrate and the fourth reflectivity corresponding to each point defect density of the two-dimensional material to be detected based on the target wavelength;

The differential reflected light intensity corresponding to each point defect density is calculated based on the third reflectivity and the fourth reflectivity.

Optionally, the computing unit 640 is used for:

respectively acquiring the grayscale value of each pixel of the monochromatic light photo of the blank substrate and the grayscale value of each pixel of the monochromatic light photo of the two-dimensional material to be detected;

According to the gray value of each pixel of the monochromatic light photo of the blank substrate and the gray value of each pixel of the monochromatic photo of the two-dimensional material to be detected, each pixel is calculated by using formula (2) The differential reflection peak intensity of :

DR _i =(Img' _i -Img _i )/Img _i (2)

Wherein, DR _i represents the differential reflection peak intensity of the ith pixel, Img' _i represents the gray value of the ith pixel of the monochromatic light photo of the two-dimensional material to be detected, and Img _i represents the monochromatic value of the blank substrate. The gray value of the ith pixel of the color photo.

The microscopic imaging detection device for the point defect density of two-dimensional materials provided by the present invention can realize the various processes realized by the method embodiments in FIGS. 1 to 5, and achieve the same technical effect.

FIG. 7 is a schematic structural diagram of an electronic device provided by the present invention. As shown in FIG. 7 , the electronic device may include: a processor (processor) 710, a communication interface (Communications Interface) 720, a memory (memory) 730 and a communication bus 740, wherein , the processor 710 , the communication interface 720 , and the memory 730 communicate with each other through the communication bus 740 . The processor 710 can invoke the logic instructions in the memory 730 to perform a method for microscopic imaging detection of point defect density of a two-dimensional material, the method comprising:

Obtain the differential reflection spectrum of the two-dimensional material to be detected;

determining a target wavelength of monochromatic light for quantifying point defect density according to the differential reflectance spectrum;

Calibrating the defect density of the to-be-detected two-dimensional material to obtain at least one point defect density;

Measure the differential reflected light intensity corresponding to each point defect density at the target wavelength, and perform function fitting according to the differential reflected light intensity and each point defect density to obtain the experience of the point defect density of the two-dimensional material to be detected. formula;

The monochromatic light with the wavelength of the target wavelength is used to illuminate the two-dimensional material to be detected, and the monochromatic light photo of the blank substrate and the monochromatic light photo of the two-dimensional material to be detected are respectively obtained. The color photo and the monochromatic photo of the two-dimensional material to be detected are calculated to obtain the differential reflection peak intensity of each pixel;

Based on the empirical formula of the point defect density and the differential reflection peak intensity of each pixel, a point defect density image of the two-dimensional material to be detected is obtained by mapping.

In addition, the above-mentioned logic instructions in the memory 730 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes: U disk, removable hard disk, Read-Only Memory (ROM, Read-Only Memory), Random Access Memory (RAM, Random Access Memory), magnetic disk or optical disk and other media that can store program codes.

In another aspect, the present invention also provides a computer program product, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, when the program instructions are executed by a computer When executed, the computer can execute the microscopic imaging detection method of the point defect density of the two-dimensional material provided by the above methods, and the method includes:

Obtain the differential reflection spectrum of the two-dimensional material to be detected;

determining a target wavelength of monochromatic light for quantifying point defect density according to the differential reflectance spectrum;

Calibrating the defect density of the to-be-detected two-dimensional material to obtain at least one point defect density;

Measure the differential reflected light intensity corresponding to each point defect density at the target wavelength, and perform function fitting according to the differential reflected light intensity and each point defect density to obtain the experience of the point defect density of the two-dimensional material to be detected. formula;

The monochromatic light with the wavelength of the target wavelength is used to illuminate the two-dimensional material to be detected, and the monochromatic light photo of the blank substrate and the monochromatic light photo of the two-dimensional material to be detected are respectively obtained. The color photo and the monochromatic photo of the two-dimensional material to be detected are calculated to obtain the differential reflection peak intensity of each pixel;

Based on the empirical formula of the point defect density and the differential reflection peak intensity of each pixel, a point defect density image of the two-dimensional material to be detected is obtained by mapping.

In yet another aspect, the present invention also provides a non-transitory computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, is implemented to perform the calculation of the point defect density of the two-dimensional material provided by the above embodiments. Microscopic imaging detection method, the method includes:

Obtain the differential reflection spectrum of the two-dimensional material to be detected;

determining a target wavelength of monochromatic light for quantifying point defect density according to the differential reflectance spectrum;

Calibrating the defect density of the to-be-detected two-dimensional material to obtain at least one point defect density;

Measure the differential reflected light intensity corresponding to each point defect density at the target wavelength, and perform function fitting according to the differential reflected light intensity and each point defect density to obtain the experience of the point defect density of the two-dimensional material to be detected. formula;

The monochromatic light with the wavelength of the target wavelength is used to illuminate the two-dimensional material to be detected, and the monochromatic light photo of the blank substrate and the monochromatic light photo of the two-dimensional material to be detected are respectively obtained. The color photo and the monochromatic photo of the two-dimensional material to be detected are calculated to obtain the differential reflection peak intensity of each pixel;

Based on the empirical formula of the point defect density and the differential reflection peak intensity of each pixel, a point defect density image of the two-dimensional material to be detected is obtained by mapping.

The device embodiments described above are only illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in One place, or it can be distributed over multiple network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution in this embodiment. Those of ordinary skill in the art can understand and implement it without creative effort.

From the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and certainly can also be implemented by hardware. Based on this understanding, the above-mentioned technical solutions can be embodied in the form of software products in essence or the parts that make contributions to the prior art, and the computer software products can be stored in computer-readable storage media, such as ROM/RAM, magnetic A disc, an optical disc, etc., includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform the methods described in various embodiments or some parts of the embodiments.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be The technical solutions described in the foregoing embodiments are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A microscopic imaging detection method for the point defect density of a two-dimensional material is characterized by comprising the following steps:

acquiring a differential reflection spectrum of a two-dimensional material to be detected; the differential reflection spectrum reflects the dielectric property change process of the two-dimensional material to be detected, which is closely related to the point defect density of the two-dimensional material to be detected;

determining the target wavelength of monochromatic light for quantifying the point defect density according to the differential reflection spectrum; the target wavelength is a wavelength which is selected from the differential reflection spectrum and corresponds to a wave crest and/or a wave trough capable of reflecting the overall dielectric property of the two-dimensional material to be detected to the greatest extent;

calibrating the defect density of the two-dimensional material to be detected to obtain at least one point defect density;

measuring the differential reflected light intensity corresponding to the defect density of each point at the target wavelength, and performing function fitting according to the differential reflected light intensity and the defect density of each point to obtain an empirical formula of the defect density of the point of the two-dimensional material to be detected;

the monochromatic light with the wavelength being the target wavelength is used for irradiating the two-dimensional material to be detected, a monochromatic light photo of a blank substrate and a monochromatic light photo of the two-dimensional material to be detected are respectively obtained, and the differential reflection peak intensity of each pixel is obtained through calculation according to the monochromatic light photo of the blank substrate and the monochromatic light photo of the two-dimensional material to be detected;

and mapping to obtain a point defect density image of the two-dimensional material to be detected based on the empirical formula of the point defect density and the differential reflection peak intensity of each pixel.

2. The method for microscopic imaging detection of point defect density in two-dimensional materials according to claim 1, wherein said determining the target wavelength of monochromatic light for quantifying the point defect density from said differential reflectance spectrum comprises:

acquiring a complex refractive index curve of the two-dimensional material to be detected;

determining peaks and/or troughs of the differential reflection spectrum;

and under the condition that the peak and/or the trough of the differential reflection spectrum correspond to the non-absorption peak position of the complex refractive index curve, acquiring the corresponding wavelength at the peak and/or the trough of the differential reflection spectrum, and taking the corresponding wavelength at the peak and/or the trough of the differential reflection spectrum as the target wavelength.

3. The microscopic imaging detection method of point defect density of two-dimensional material according to claim 1, wherein said determining a target wavelength of monochromatic light for quantifying point defect density from said differential reflectance spectrum comprises:

determining peaks and/or troughs of the differential reflection spectrum;

and taking the wavelength corresponding to any peak or trough of the differential reflection spectrum as the target wavelength.

4. The microscopic imaging detection method of point defect density of two-dimensional material according to claim 1, wherein said determining a target wavelength of monochromatic light for quantifying point defect density from said differential reflectance spectrum comprises:

and selecting wavelengths corresponding to a plurality of wave crests or wave troughs of the differential reflection spectrum as the target wavelengths.

5. The microscopic imaging detection method for the point defect density of the two-dimensional material according to claim 1, wherein the obtaining of the differential reflection spectrum of the two-dimensional material to be detected comprises:

respectively obtaining a first reflectivity of a blank substrate and a second reflectivity of a two-dimensional material to be detected;

based on the first reflectivity and the second reflectivity, calculating to obtain a differential reflection spectrum of the to-be-detected two-dimensional material by using a formula (1):

（1）

wherein,

representing a differential reflection spectrum of the two-dimensional material to be detected,

which is indicative of the second reflectivity is,

representing the first reflectivity.

6. The microscopic imaging detection method of the two-dimensional material point defect density according to claim 1, wherein the measuring the differential reflected light intensity corresponding to each point defect density at the target wavelength comprises:

respectively obtaining a third reflectivity of a blank substrate and a fourth reflectivity corresponding to each point defect density of the two-dimensional material to be detected based on the target wavelength;

and calculating differential reflected light intensity corresponding to each point defect density based on the third reflectivity and the fourth reflectivity.

7. The microscopic imaging detection method of the point defect density of the two-dimensional material according to claim 1, wherein the calculating of the differential reflection peak intensity of each pixel according to the monochromatic photo of the blank substrate and the monochromatic photo of the two-dimensional material to be detected comprises:

respectively obtaining the gray value of each pixel of the monochrome photo of the blank substrate and the gray value of each pixel of the monochrome photo of the two-dimensional material to be detected;

calculating to obtain the differential reflection peak intensity of each pixel by using a formula (2) according to the gray value of each pixel of the monochrome photo of the blank substrate and the gray value of each pixel of the monochrome photo of the two-dimensional material to be detected:

（2）

wherein,

is shown as

The differential reflection peak intensity of each pixel,

second of a monochromatic photo representing the two-dimensional material to be inspected

The gray-scale value of each pixel,

(ii) a monochromatic photomicrograph representing the blank substrate

The gray value of each pixel.

8. A microscopic imaging detection device for point defect density of two-dimensional material is characterized by comprising:

the acquisition unit is used for acquiring a differential reflection spectrum of the two-dimensional material to be detected; the differential reflection spectrum reflects the dielectric property change process of the two-dimensional material to be detected, which is closely related to the point defect density of the two-dimensional material to be detected;

the determining unit is used for determining the target wavelength of the monochromatic light for quantifying the point defect density according to the differential reflection spectrum; the target wavelength is a wavelength corresponding to a peak and/or a trough which is selected from the differential reflection spectrum and can reflect the overall dielectric property of the two-dimensional material to be detected to the greatest extent;

the calibration unit is used for calibrating the defect density of the two-dimensional material to be detected to obtain at least one point defect density;

the measuring unit is used for measuring the differential reflected light intensity corresponding to the defect density of each point at the target wavelength, and performing function fitting according to the differential reflected light intensity and the defect density of each point to obtain an empirical formula of the point defect density of the two-dimensional material to be detected;

the calculating unit is used for irradiating the two-dimensional material to be detected by using monochromatic light with the wavelength of the target wavelength to respectively obtain a monochromatic photo of a blank substrate and a monochromatic photo of the two-dimensional material to be detected, and calculating to obtain the differential reflection peak intensity of each pixel according to the monochromatic photo of the blank substrate and the monochromatic photo of the two-dimensional material to be detected;

and the mapping unit is used for mapping to obtain a point defect density image of the two-dimensional material to be detected based on the empirical formula of the point defect density and the differential reflection peak intensity of each pixel.

9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor when executing the computer program performs the steps of the method for microscopic imaging detection of two-dimensional material point defect density according to any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium, on which a computer program is stored, wherein the computer program, when executed by a processor, implements the steps of the method for microscopic imaging detection of two-dimensional material point defect density according to any one of claims 1 to 7.

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