Raman spectroscopy method for detecting vanadium-doped transition metal chalcogenide based on characteristic peaks caused by vanadium doping

Abstract

The application provides a Raman spectrum detection method for vanadium-doped transition metal chalcogenide compounds based on characteristic peaks caused by vanadium doping, Raman detection is performed on a sample to be detected, Raman spectrum is obtained and processed, and characteristic peaks of the vanadium-doped transition metal chalcogenide compounds are determined; a polarized Raman detection method is used, a polarized optical component is added to a test light path of a Raman spectrometer and a rotation angle θ of a 1 / 2 glass sheet in the polarized optical component is adjusted, polarized Raman detection is performed on the sample to be detected, and a doping concentration distribution is determined. According to the technical scheme of the application, based on the characteristic that doping of vanadium atoms can cause Raman characteristic peaks related to vanadium doping in Raman spectrum of two-dimensional transition metal chalcogenide compounds, the accuracy of analysis of the concentration of the doping elements is further improved through polarized Raman detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of two-dimensional transition metal chalcogenide detection technology, in particular to a Raman spectrum detection method for vanadium-doped transition metal chalcogenide based on characteristic peaks caused by vanadium doping. BACKGROUND

[0002] Two-dimensional transition metal chalcogenides have great application prospects in the fields of future electronics, optoelectronics, energy valley spin devices, etc. due to their excellent physical properties and atomic-level thickness. Substitutional doping can adjust the physical properties of two-dimensional transition metal chalcogenides or endow them with functional properties, further expanding the application range of two-dimensional transition metal chalcogenides. As a doping atom, vanadium can not only p-dope two-dimensional transition metal chalcogenides, expand the selection range of p-type two-dimensional semiconductor materials, and solve the problem of too few p-type two-dimensional semiconductors, but also endow various two-dimensional transition metal chalcogenides with room-temperature ferromagnetism, provide material support for spintronics research, and promote the development of high-performance, low-power micro-nano devices based on spintronics.

[0003] In the prior art, two-dimensional transition metal chalcogenides can be characterized by Raman spectrum. The existing Raman spectrum characterization mainly relies on the Raman characteristic peaks of transition metal chalcogenides themselves, mainly including E 2g and A 1g peaks to determine the following characterization targets. The characterization targets include determining the doping concentration, charge transfer and stress conditions, electron-phonon coupling strength, etc. in vanadium-doped two-dimensional transition metal chalcogenides. For example, Chinese invention patent CN110155959A discloses a method for preparing two-dimensional transition metal alloy chalcogenide by confined chemical vapor deposition. The technical solution is to prepare single-layer large-size transition metal alloy chalcogenide from precursor source materials molybdenum oxide and tungsten oxide. Raman spectrum is used in combination with optical microscope, field emission scanning electron microscope, transmission electron microscope and atomic force microscope. The results show that the product is two-dimensional transition metal alloy chalcogenide. In the aspect of chemical vapor deposition method for preparing vanadium atom-doped two-dimensional tungsten disulfide atomic crystal and performance research, Yun Zhiqiang, Yanshan University, Master's thesis, May 2020, discloses a method for growing vanadium-doped WS2 two-dimensional crystal by two-step method, and it is found by Raman spectrum characterization that there are sulfur-vanadium bond vibration peaks at the edge, and there are also characteristic Raman peaks E 2g and A 1g of WS2. However, compared with the central region, the E 2g peak of the edge region shifts slightly to low wave number, confirming that the peripheral epitaxial growth of WS2 is vanadium-doped WS2, i.e. the vanadium atom concentration gradient changes in the grown vanadium-doped single-layer WS2 two-dimensional crystal. However, vanadium doping can cause the Raman E 2g and A 1gThe peaks split and produce many new Raman peaks with E 2g and A 1g peaks mixed together. The prior art determines the charge transfer and stress by the shift of the Raman peak position when analyzing the doping effect of the E 2g and A 1g peaks, and determines the electron-phonon coupling strength by the change of the half-height width of the Raman peak. The prior art does not consider the influence of the splitting of the E 2g and A 1g peaks caused by vanadium doping on the analysis of the doping concentration, so that the doping concentration obtained by analyzing the Raman E 2g and A 1g peaks has a large error.

[0004] Further, the paper Doping Concentration Modulation in Vanadium-Doped Monolayer Molybdenum Disulfide for Synaptic Transistors (ACS Nano, 2021, 15, 7340-7347) points out that low-concentration vanadium-doped MoS2 has a typical Raman spectrum of MoS2, only the characteristic E 2g and A 1g peaks of molybdenum disulfide are observed, but the charge transfer and lattice strain induced by vanadium doping will make the E 2g and A 1g peaks move to low wavenumbers. When heavily doped, the Raman spectrum changes significantly. First, the E 2g and A 1g peaks split, and a new peak appears at 391.8 cm -1 . Second, several additional peaks appear in the range of 100-300 cm -1 , which is caused by the lattice distortion induced by vanadium atoms. Third, a special peak appears at 323 cm -1 , the intensity of which is positively correlated with the concentration of vanadium atoms, which can be used as a characteristic peak of high-concentration vanadium-doped molybdenum disulfide. At the same time, vanadium doping induces the generation of charge transfer and lattice strain in MoS2, making the E 2g and A 1g peaks move to lower wavenumbers. Peak position statistics show that the A 1g and E 2g peaks of low-concentration MoS2 have a slight shift, indicating that weak charge transfer effect and small lattice strain are generated in lightly doped molybdenum disulfide. However, the technical solution does not further process the characteristic peak of high-concentration vanadium-doped molybdenum disulfide, that is, the doping concentration obtained by the technical solution does not consider the error caused by the splitting of the peak caused by high-concentration vanadium doping.

[0005] In summary, the prior art has the following problems in characterizing vanadium-doped transition metal chalcogenides by Raman spectroscopy: (1) When analyzing the doping effect by E 2g and A 1g peaks, the charge transfer and stress are determined by the shift of the Raman peak position, and the electron-phonon coupling strength is determined by the half-height width of the Raman peak. However, vanadium doping can split the E 2g and A 1g peaks of transition metal chalcogenides, resulting in many new Raman peaks mixed with E 2g and A 1g peaks. The E 2g and A 1g peaks need to be extracted by peak separation, which is affected by peak separation methods, software, and human factors, and is prone to errors, affecting the analysis results. (2) When analyzing the doping concentration by E 2g and A 1g peaks, the charge transfer and stress need to be considered and analyzed to determine the doping concentration, which cannot directly reflect the doping concentration and cannot intuitively display the doping concentration distribution through Raman Mapping spectrum. SUMMARY

[0006] Therefore, to solve the above problems, the present application discloses a Raman spectroscopy detection method for vanadium-doped transition metal chalcogenides based on characteristic peaks caused by vanadium doping. Based on the new Raman characteristic peaks induced by vanadium doping in the Raman spectrum of two-dimensional transition metal chalcogenides, the accuracy of analyzing the doping element concentration is further improved through polarized Raman detection.

[0007] To achieve the above purpose, the present application provides the following technical solutions.

[0008] A Raman spectroscopy detection method for vanadium-doped transition metal chalcogenides based on characteristic peaks caused by vanadium doping, characterized by: performing Raman detection on the sample to be detected, obtaining the Raman spectrum and processing it to determine the Raman characteristic peaks of the vanadium-doped transition metal chalcogenides; using a polarized Raman detection method, adding a polarized optical component in the test optical path of the Raman spectrometer, and adjusting the rotation angle θ of the 1 / 2 glass in the polarized optical component to perform polarized Raman detection on the sample to be detected and determine the doping concentration distribution.

[0009] Further, the polarized Raman detection method specifically includes the following steps:

[0010] (1) Multiple rotation angle θ detection: adjust the rotation angle θ of the 1 / 2 glass multiple times, and record the intensity of the characteristic peaks of the vanadium-doped transition metal chalcogenides at different rotation angles θ each time;

[0011] (2) plot a polar coordinate graph of intensity of the characteristic peak as a function of 1 / 2-plate rotation angle θ;

[0012] (3) fitting of the polar coordinate graph: fitting the polar coordinate graph with formula I = I0 x sin 2 (θ + θ0); wherein, I is the measured intensity of the characteristic peak; I0 and θ0 are fitting constants;

[0013] determining the angle θ max corresponding to the maximum intensity of the characteristic peak and the angle θ min corresponding to the minimum intensity of the characteristic peak through the fitting;

[0014] (4) setting the 1 / 2-plate at the angle θ max and the angle θ min for mapping scanning and processing of the Raman mapping to obtain the polarized Raman mapping of the vanadium-doped two-dimensional transition metal chalcogenide at the two polarization angles and determine the distribution of the vanadium doping concentration.

[0015] Further, in step 1, the 1 / 2-plate rotation angle θ is adjusted from 0-180°, and adjusted every 5-20 degrees for polarized Raman detection.

[0016] Further, in step 4, the rotation angle of the 1 / 2-plate is set to θ max , mapping scanning is performed and processed to obtain the polarized Raman mapping of the vanadium-doped two-dimensional transition metal chalcogenide at the angle θ max ;

[0017] The 1 / 2-plate rotation angle is set to θ min , mapping scanning is performed and processed to obtain the polarized Raman mapping at the angle θ min ;

[0018] According to the color distribution in the polarized Raman mapping at the angle θ max and the polarized Raman mapping at the angle θ min , the distribution of the doping concentration is determined.

[0019] Further, the following steps are included:

[0020] S1, detection of Raman spectrum: placing a growth substrate loaded with a chemical vapor deposition vanadium-doped transition metal chalcogenide on a Raman spectrometer test platform, focusing the sample to be detected by an optical microscope, and detecting a laser confocal Raman spectrum to obtain a Raman spectrum;

[0021] S2, processing of the Raman spectrum: processing the Raman spectrum, setting a baseline, calibrating the peak position of the vanadium-doped transition metal sulfide according to the Raman peak of the growth substrate material, determining the characteristic peak of the vanadium-doped transition metal chalcogenide, performing fitting analysis on the characteristic peak, determining the peak position, peak intensity and half-width of the characteristic peak; calculating the charge transfer and stress according to the peak position shift, determining the electron-phonon coupling strength according to the half-width, and determining the concentration distribution of vanadium doping;

[0022] S3, Mapping scanning: performing Mapping scanning on the vanadium-doped transition metal sulfide sheet to be detected, and setting the Mapping scanning range to be 50-100 cm -1 around the characteristic peak in S2, to obtain a Mapping spectrum;

[0023] S4, Mapping graph processing: processing the Mapping spectrum obtained in S3, removing noise points, setting the spectrum intensity range according to the baseline and the highest peak intensity obtained by testing, setting the spectrum display color, analyzing the color uniformity in the Raman Mapping spectrum, and determining the uniformity of the doping vanadium atomic concentration distribution;

[0024] S5, polarized Raman detection: adding a polarized optical component in the test light path of the Raman spectrometer, adjusting the rotation angle θ of the 1 / 2 glass in the polarized optical component, and performing the polarized Raman detection on the sample to be detected to determine the uniformity of the vanadium doping concentration distribution.

[0025] Further, in S1, the optical microscope magnification range is 50-1500 times;

[0026] The detection conditions of the laser confocal Raman spectrum are: laser wavelength 266nm-1064nm, laser intensity attenuation 0.1%-100%, test integration time 0.1-100s, integration times 1-10 times, and Raman spectrum test range 100cm -1 -1000cm -1 .

[0027] Further, in S2, the charge transfer and stress are calculated according to the peak position shift, the doping concentration is calculated according to the peak intensity, and the electron-phonon coupling strength is determined and a database is established according to the half-width;

[0028] Further, in S3, the excitation laser wavelength is consistent with the above Raman test wavelength, the laser intensity attenuation is 0.1%-100%, the scanning time integration time is 0.1-1s, the integration times are 1-5 times, and the scanning test moving step is 0.1μm-5μm.

[0029] Further, in S1, the growth substrate material loaded with the chemical vapor grown vanadium-doped transition metal chalcogenide is a silicon wafer with a silicon oxide layer, quartz or mica.

[0030] Further, the vanadium-doped transition metal chalcogenide includes, but is not limited to, any one of vanadium-doped molybdenum disulfide, vanadium-doped tungsten disulfide, vanadium-doped molybdenum diselenide, vanadium-doped tungsten diselenide, vanadium-doped tin disulfide, vanadium-doped tin diselenide, vanadium-doped niobium disulfide, vanadium-doped niobium diselenide, vanadium-doped tantalum disulfide, or vanadium-doped tantalum diselenide.

[0031] The characteristics of the new Raman characteristic peak induced by the doped vanadium atoms in the Raman spectrum of the two-dimensional transition metal chalcogenide are analyzed, the characteristic peak exists alone without other peaks mixed with it, without complex peak separation processing, and the peak position and half-height width are sensitive to the doping charge and stress, so that the changes of the charge transfer, stress and electron-phonon coupling strength caused by vanadium doping can be more accurately determined. Meanwhile, the intensity of the characteristic peak is proportional to the doping concentration, which can directly reflect the doping concentration. Through Raman Mapping characterization, the distribution state of the vanadium element concentration in the two-dimensional transition metal chalcogenide sheet layer can be directly displayed. Based on the above characteristics, by using the technical solution of the present application, the accuracy of the analysis of the doping element concentration is further improved through polarized Raman detection.

[0032] The beneficial technical effects obtained by the present application are as follows:

[0033] 1. The technical solution adopted by the present application is based on the new Raman characteristic peak induced by the doped vanadium atoms in the Raman spectrum of the two-dimensional transition metal chalcogenide, which further improves the accuracy of the analysis of the doping element concentration through polarized Raman detection.

[0034] 2. By using the technical solution of the present application, the charge transfer, stress, electron-phonon coupling strength and doping concentration distribution in the vanadium-doped transition metal chalcogenide can be quickly and non-destructively determined through Raman spectrum characterization, and the results are more accurate.

[0035] 3. By using the technical solution of the present application, the characteristic peak of the vanadium-doped two-dimensional transition metal chalcogenide is determined through Raman spectrum, which exists alone without other peaks mixed with it, without complex peak separation processing, and through the characterization of the characteristic peak intensity, half-height width and peak position, the doping concentration, charge transfer, stress and electron-phonon coupling strength can be more accurately determined, and the characterization effect is intuitive.

[0036] 4. The technical solution of the present application uses existing detection means, optimizes the detection method through polarized Raman detection means, draws the polar coordinate graph of the characteristic peak intensity changing with 1 / 2 glass rotation angle θ, and determines the rotation angle θ corresponding to the maximum and minimum of the Raman characteristic peak intensity of the vanadium-doped two-dimensional transition metal chalcogenide.max with θ min , finally set the 1 / 2 glass rotation angle to θ max with θ min , the polarization Raman Mapping test is carried out, the polarization Raman spectrum is obtained, and more accurate doping concentration and doping element distribution results are obtained, and the operation is convenient. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The polarization Raman detection of the embodiments 1 and 2 of the application and the principle diagram of the Raman detection without polarization.

[0038] Figure 2 The Raman spectrum of the vanadium-doped tungsten disulfide in the embodiment 1 of the application.

[0039] Figure 3 The peak position analysis diagram of the Raman characteristic peak of the vanadium-doped tungsten disulfide in the embodiment 1 of the application.

[0040] Figure 4 The column chart of the Raman characteristic peak intensity analysis of the vanadium-doped tungsten disulfide in the embodiment 1 of the application.

[0041] Figure 5 The column chart of the Raman characteristic peak half-width analysis of the vanadium-doped tungsten disulfide in the embodiment 1 of the application.

[0042] Figure 6 The diagram of the relationship between the Raman characteristic peak intensity caused by vanadium doping and the 1 / 2 glass rotation angle θ in the embodiment 1 of the application.

[0043] Figure 7a The non-polarized Raman Mapping diagram of the vanadium-doped tungsten disulfide measured based on the Raman characteristic peak caused by vanadium doping in the embodiment 1 of the application.

[0044] Figure 7b The 1 / 2 glass rotation angle of the vanadium-doped tungsten disulfide measured based on the Raman characteristic peak caused by vanadium doping in the embodiment 1 of the application is θ max under the condition.

[0045] Figure 7c The 1 / 2 glass rotation angle of the vanadium-doped tungsten disulfide measured based on the Raman characteristic peak caused by vanadium doping in the embodiment 1 of the application is θ min under the condition.

[0046] Figure 8 The Raman spectrum of the vanadium-doped molybdenum disulfide in the embodiment 2 of the application.

[0047] Figure 9 The diagram of the relationship between the Raman characteristic peak intensity caused by vanadium doping and the 1 / 2 glass rotation angle θ in the embodiment 2 of the application.

[0048] Figure 10a The non-polarized Raman Mapping diagram of the vanadium-doped molybdenum disulfide measured based on the Raman characteristic peak caused by vanadium doping in the embodiment 2 of the present application.

[0049] Figure 10b The 1 / 2 glass sheet rotation angle of the vanadium-doped molybdenum disulfide measured based on the Raman characteristic peak caused by vanadium doping in the embodiment 2 of the present application is θ max under the condition of Raman Mapping diagram.

[0050] Figure 10c The 1 / 2 glass sheet rotation angle of the vanadium-doped molybdenum disulfide measured based on the Raman characteristic peak caused by vanadium doping in the embodiment 2 of the present application is θ min under the condition of Raman Mapping diagram. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments of the present application.

[0052] The technical scheme of the present application optimizes the Raman spectrum characterization technical scheme of the vanadium doping concentration, charge transfer, stress, electron-phonon coupling strength and the like in the vanadium-doped transition metal chalcogenide. The vanadium-doped transition metal chalcogenide includes but is not limited to vanadium-doped molybdenum disulfide, vanadium-doped tungsten disulfide, vanadium-doped molybdenum diselenide, vanadium-doped tungsten diselenide, vanadium-doped tin disulfide, vanadium-doped tin diselenide, vanadium-doped niobium disulfide, vanadium-doped niobium diselenide, vanadium-doped tantalum disulfide, vanadium-doped tantalum diselenide and the like.

[0053] Further, the growth substrate material loaded with the chemical vapor grown vanadium-doped transition metal chalcogenide can be a silicon wafer with a silicon oxide layer, quartz, mica and other substrate materials.

[0054] The Raman spectrum characterization of the vanadium-doped single-layer tungsten disulfide and the vanadium-doped single-layer molybdenum disulfide will be further described below.

[0055] Embodiment 1: Raman spectrum detection of vanadium-doped single-layer tungsten disulfide sheet

[0056] The laser confocal Raman spectrometer used in the Raman detection in the embodiments of the present application is LabRAB HREvolution of Japan. When the Raman spectrum detection is performed, the doping vanadium atom concentration and its distribution can be obtained more intuitively and accurately through the correction of the polarization optical assembly thereof. See Figure 1For the present embodiment, the principle of polarized Raman and non-polarized Raman detection is shown in the schematic diagram. Among them, the polarized Raman detection is realized by adding a polarized optical component on the basis of laser confocal Raman detection. The polarized optical component includes a polarizer, a 1 / 2 glass and an analyzer. The rotation angle of the 1 / 2 glass is adjusted from 0 to 180° in steps. The laser passes through the polarizer and the 1 / 2 glass, and is focused on the sample to be detected through the optical microscope. The polarization state of the Raman scattered light emitted from the surface of the sample to be detected is detected again through the analyzer, and the polarized Raman Mapping diagram is obtained. Compared with the non-polarized Raman Mapping diagram, the distribution of the vanadium doping concentration in the sample to be detected is determined.

[0057] By adjusting the rotation angle θ of the 1 / 2 glass from 0 to 180°, the polarized Raman detection is performed every 10°.

[0058] The test parameters include: (1) point measurement: laser intensity 1-100%, laser spot size: 1-10 microns, integration time 1-50s, integration times 1-10 times; (2) Mapping measurement: laser intensity 0.1-50%, laser spot size: 1-10 microns, integration time 0.1-2s, integration times 1 time; (3) polarization measurement parameters: polarization angle adjustment, i.e. 1 / 2 glass rotation angle adjustment step size is 5-20°.

[0059] In the specific operation process, the excitation laser wavelength can be selected as 266nm, 488nm, 532nm.

[0060] The selectable laser attenuation amplitude can be 0.1%, 1%, 3.2%, 5%, 10%, 25%, 50%, 100%.

[0061] The selectable optical microscope magnification can be 50, 100, 200, 500, 1000, 1500 times.

[0062] The selectable Raman test integration time can be 0.1s, 0.2s, 0.5s, 1s, 2s, 5s, 10s.

[0063] The selectable Raman integration times can be 1, 2, 3, 4, 5 times.

[0064] The selectable Mapping scanning test moving step can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.75, 1, 2, 3, 4, 5 microns.

[0065] The selectable 1 / 2 glass rotation angle step of the polarized Raman test can be 5°, 10°, 15° or 20°, and the 1 / 2 glass rotation angle range is 0-180°.

[0066] The aforementioned laser confocal Raman spectrometer was used to perform Raman spectroscopy on vanadium-doped tungsten disulfide to more accurately analyze and determine the uniformity of vanadium doping concentration distribution. Specific operational steps included:

[0067] (1) A silicon wafer loaded with vanadium-doped tungsten disulfide grown by chemical vapor deposition was placed on the Raman spectrometer testing platform. The sample to be tested was focused using an optical microscope, and laser confocal Raman spectroscopy was performed. The optical microscope magnification was 1000x, the excitation laser wavelength was 532nm, the laser intensity attenuation was 5%, the test integration time was 10s, the integration was performed twice, and the Raman test range was 100cm. -1 -600cm -1 .

[0068] (2) Process the measured Raman spectrum, set a baseline, calibrate the peak position of vanadium-doped tungsten disulfide according to the Raman peak of the growth substrate material, and calibrate the peak position. Figure 1 ).pass Figure 1 As can be seen from the Raman spectra of undoped tungsten disulfide and vanadium-doped tungsten disulfide, the Raman characteristic peak caused by vanadium doping is at 212 cm⁻¹. -1 The peak intensity is sensitive to the doping concentration, and the doping concentration achieved by VCl3 is higher than that of NH4VO3, which can be determined by the peak intensity.

[0069] Further fitting analysis was performed on this characteristic peak to determine its peak position. Figure 3 Peak strength () Figure 4 ) and half-height width ( Figure 5 ). Figure 3 The Raman characteristic peaks of vanadium-doped tungsten disulfide shown shift to lower wavenumbers, indicating that vanadium atoms inject holes into tungsten disulfide, causing tensile lattice strain. The amount of charge injection and the magnitude of strain can be calculated by the wavenumber shift of the peak position. Figure 4 The Raman characteristic peak intensity of vanadium-doped tungsten disulfide is shown to be higher than that of tungsten disulfide A. 1g The peak is more sensitive to the doping concentration; while Figure 5 The increased full width at half maximum (FWHM) of the Raman characteristic peak in vanadium-doped tungsten disulfide indicates an increased electron-phonon coupling strength, and its ratio to E0.05 is also higher. 2g and A 1g The peak is more sensitive.

[0070] Obviously, through Figures 3-5 Analysis revealed that vanadium doping caused p-type doping of tungsten disulfide and produced lattice tensile strain based on peak position shift. Different dopants could lead to different doping concentrations based on peak intensity changes. Vanadium doping could enhance the electron-phonon coupling strength in tungsten disulfide based on full width at half maximum (FWHM).

[0071] (3) A mapping scan was performed on the vanadium-doped tungsten disulfide sheet to be tested, with the scan range set to 175 cm⁻¹.-1 -250 cm -1 The excitation laser wavelength is 532 nm, the laser intensity attenuation is 1%, the scanning time integral time is 0.2 s, the integral number is 1, and the scanning test moving step is 0.2 μm. The mapping diagram of vanadium-doped tungsten disulfide is obtained, as shown in FIG. 6-a.

[0072] (4) The Raman mapping diagram is processed, the baseline is set, the noise points are removed, the intensity range of the diagram is set according to the baseline and the highest peak intensity obtained by testing, the color display of the diagram is set, and the color uniformity in the mapping diagram is analyzed.

[0073] (5) A polarization optical assembly is added to the test light path of the Raman spectrometer, including a polarizer, an analyzer and a 1 / 2 plate, the rotation angle θ of the 1 / 2 plate is adjusted from 0-180°, and the adjustment is made every 10 degrees. After each adjustment, step (2) is repeated to perform polarization Raman detection on the sample to be tested.

[0074] (6) Step (5) is repeated, the Raman characteristic peak intensity of vanadium-doped tungsten disulfide under different rotation angles of the 1 / 2 plate is recorded, and a polar coordinate diagram of the characteristic peak intensity changing with the rotation angle θ of the 1 / 2 plate is drawn. The polar coordinate diagram is fitted by the formula I=I0× sin 2 (θ+θ0), I is the measured characteristic peak intensity, I0 and θ0 are fitting constants. Through fitting, it is determined that the angles corresponding to the highest and lowest characteristic peak intensities are θ max and θ min , respectively (see Figure 6 ). It can be seen from Figure 6 that the relationship between the Raman characteristic peak intensity of vanadium-doped tungsten disulfide and the rotation angle of the 1 / 2 plate is θ max and θ min are 15° and 55°, respectively.

[0075] (7) The rotation angle of the 1 / 2 plate is set to θ max , step (3) is repeated, the obtained Raman mapping diagram is processed, the noise points are removed, the intensity range of the diagram is set according to the baseline and the highest peak intensity obtained by testing, the color display of the diagram is set, and the Raman mapping diagram under this polarization angle is obtained (see FIG. 7-b). It can be seen from FIG. 7-b that the polarization Raman mapping diagram of vanadium-doped tungsten disulfide, and the rotation angle θ of the 1 / 2 plate is 15°.

[0076] The rotation angle of the 1 / 2 plate is set to θ minRepeat step (3) to process the obtained Raman mapping spectrum, remove noise, set the spectrum intensity range according to the baseline and peak intensity obtained from the test, set the spectrum display color scheme, and obtain the Raman mapping image under this polarization angle (see Figure 7-c). As can be seen from Figure 7-c, the polarization Raman mapping image of vanadium-doped tungsten disulfide has a 1 / 2 glass slide rotation angle θ of 55°.

[0077] Figures 7-a, 7-b, and 7-c show that the Raman mapping diagrams based on the characteristic peaks of vanadium-doped tungsten disulfide exhibit inconsistent brightness (different characteristic peak intensities) without polarization. Even after polarization, the brightness inconsistency persists. However, comparing the results measured at different polarization angles reveals that some points with lower brightness are in the same location (indicated by the arrows in the figures). This confirms the presence of points with lower doping concentrations in the sample, while the other parts are likely due to testing system errors. This demonstrates that the test results at different polarization angles can be mutually verified, eliminating the influence of testing errors. It confirms that the doping concentration is consistent at most locations in the sample, with only a few locations exhibiting uneven doping due to impurity adsorption.

[0078] pass Figures 1-6 The results show that the Raman characteristic peaks induced by vanadium doping can more sensitively and accurately determine the doping concentration, charge transfer, stress, and electron-phonon coupling strength in vanadium-doped two-dimensional transition metal chalcogenides. Adding a polarization component for polarized Raman testing can further eliminate testing errors, thereby correcting the results of unpolarized laser confocal Raman spectroscopy. This results in more accurate information on the concentration and distribution of doping elements in vanadium-doped tungsten disulfide, providing technical support for high-precision applications in actual production processes.

[0079] Example 2: Detection of vanadium-doped monolayer molybdenum disulfide sheets

[0080] (1) A vanadium-doped molybdenum disulfide growth substrate loaded with chemical vapor deposition was placed on a Raman spectrometer testing platform. The sample to be tested was focused using an optical microscope, and laser confocal Raman spectroscopy was performed. The optical microscope magnification was 1000x, the excitation laser wavelength was 532nm, the laser intensity attenuation was 10%, the integration time was 10s, the integration was performed twice, and the Raman test range was 100cm. -1 -600cm -1 .

[0081] (2) Process the measured Raman spectrum, set a baseline, calibrate the peak position of vanadium-doped molybdenum disulfide based on the Raman peak of the growth substrate material, and calibrate the peak position (see [reference]). Figure 8 ),pass Figure 8 It can be determined that the characteristic peak caused by vanadium doping is at 323 cm⁻¹. -1 .

[0082] (3) A mapping scan was performed on the vanadium-doped molybdenum disulfide sheet to be tested to obtain the mapping image under non-polarization conditions, as shown in Figure 10-a. The scanning range was set to 300 cm. -1 -350cm -1 Range. The excitation laser wavelength is 532nm, the laser intensity attenuation is 1%, the scanning time integration time is 0.5s, the number of integrations is 1, and the scanning test movement step size is 0.1μm.

[0083] (4) Add polarization optical components, including polarizer, analyzer and 1 / 2 glass slide, to the test optical path of Raman spectrometer. Adjust the rotation angle θ of 1 / 2 glass slide from 0 to 180°, adjusting once every 10 degrees. Repeat step (2) after each adjustment to perform polarization Raman detection on the sample to be tested.

[0084] (5) Repeat step (4) and record the Raman characteristic peak intensity of vanadium-doped transition metal sulfides at different angles on the half-glass slide. Plot a polar graph of the characteristic peak intensity as a function of the rotation angle θ. The polar graph is plotted using the formula I = I0 × sin 2 The equation (θ + θ0) is fitted, where I is the measured characteristic peak intensity, and I0 and θ0 are fitting constants. The angles corresponding to the highest and lowest characteristic peak intensities are determined by the fitting process, θ0 and θ0, respectively. max With θ min (See also) Figure 9 ),pass Figure 9 It can be seen that the Raman characteristic peak intensity of vanadium-doped molybdenum disulfide is related to the rotation angle of the half-glass slide, θ. max With θ min The angles are 15° and 60° respectively.

[0085] (6) Set the rotation angle of the half-glass slide to θ. max Repeat step (3) to process the obtained Raman Mapping spectrum, remove noise, set the spectrum intensity range according to the baseline and peak intensity obtained from the test, set the spectrum display color, and obtain the Raman Mapping image under this polarization angle (see Figure 10-b). As can be seen from Figure 10-b, the polarization Raman Mapping image of vanadium-doped molybdenum disulfide has a 1 / 2 glass slide rotation angle θ of 15°, and the uniform color confirms the uniformity of the doping concentration.

[0086] Set the rotation angle of the half-glass slide to θ. min, repeat step (3), process the obtained Raman Mapping spectrum, remove noise points, set the spectrum intensity range according to the test baseline and the highest peak intensity, set the spectrum display color, and obtain the Raman Mapping spectrum under the polarization angle (see FIG. 10-c). As can be seen from FIG. 10-c, the polarization Raman Mapping spectrum of vanadium-doped molybdenum disulfide, with a 1 / 2 glass sheet rotation angle θ of 60°, shows that all Raman peaks disappear, confirming the uniformity of the doping concentration.

[0087] According to the above Figure 10a 、 10b and the color distribution in the three Mapping spectra in FIGS. 10a, 10b and 10c, the polarization Raman detection can further eliminate test errors and further more accurately determine the doping concentration distribution, thereby providing technical support for the detection of the uniformity of the doping concentration distribution in vanadium-doped molybdenum disulfide.

[0088] The detection results of Example 1 and Example 2 show that by polarization Raman characterization, the charge transfer, stress, electron-phonon coupling strength and doping concentration distribution in vanadium-doped transition metal chalcogenide compounds can be quickly and non-destructively determined, and the effect is more accurate and intuitive. Obviously, the technical solution of the present application can be used to detect the charge transfer, stress, electron-phonon coupling strength and doping concentration distribution in vanadium-doped transition metal chalcogenide compounds, and the technical solution is obtained by optimizing the detection process based on the prior art, which provides more accurate detection technical support for the practical application of vanadium-doped transition metal sulfide.

[0089] The above is only a preferred embodiment of the present application, which does not limit the protection scope of the present application. For those skilled in the art, the present application can have various changes and variations. Any changes, modifications, replacements, integrations and parameter changes to these embodiments within the spirit and principles of the present application, which can realize the same functions without departing from the principles and spirit of the present application, fall within the protection scope of the present application.

Claims

1. A Raman spectroscopic detection method for vanadium-doped transition metal chalcogenides based on characteristic peaks induced by vanadium doping, characterized in that, Raman detection was performed on the sample to be tested to obtain the Raman spectrum, which was then processed to determine the Raman characteristic peaks of vanadium-doped transition metal chalcogenides. Polarized Raman detection was then performed on the sample to be tested by adding a polarization optical component to the test optical path of the Raman spectrometer and adjusting the rotation angle θ of the half glass slide in the polarization optical component to determine the vanadium doping concentration distribution. The vanadium-doped transition metal chalcogenide is any one of vanadium-doped molybdenum disulfide, vanadium-doped tungsten disulfide, vanadium-doped molybdenum diselenide, vanadium-doped tungsten diselenide, vanadium-doped tin disulfide, vanadium-doped tin diselenide, vanadium-doped niobium disulfide, vanadium-doped niobium diselenide, vanadium-doped tantalum disulfide, or vanadium-doped tantalum diselenide.

2. The Raman spectroscopy detection method for vanadium-doped transition metal chalcogenides based on characteristic peaks induced by vanadium doping as described in claim 1, characterized in that, The polarization Raman detection method specifically includes the following steps: (1) Raman detection at multiple rotation angles θ: The rotation angle θ of the 1 / 2 glass slide is adjusted multiple times, and the intensity of the characteristic peak of the vanadium-doped transition metal chalcogenide is recorded at each different rotation angle θ. (2) Plot the polar coordinates of the intensity of the characteristic peak as a function of the rotation angle θ of the half-slide; (3) Fitting the polar coordinate graph: The polar coordinate graph is fitted using the formula I = I0 × sin 2 The fit is performed using (θ+θ0); where I is the measured intensity of the characteristic peak; I0 and θ0 are fitting constants; after fitting, the angle θ corresponding to the maximum intensity of the characteristic peak is determined. max and the angle θ corresponding to the lowest intensity min ; (4) Set the 1 / 2 glass slide at θ step by step. max and θ min Under the given conditions, mapping scans and Raman mapping spectrum processing were performed to obtain polarized Raman mapping images of vanadium-doped two-dimensional transition metal chalcogenides, thereby determining the doping concentration distribution.

3. The Raman spectroscopy detection method for vanadium-doped transition metal chalcogenides based on characteristic peaks induced by vanadium doping as described in claim 2, characterized in that, In step 1, the rotation angle θ of the half-glass slide is adjusted from 0 to 180°, and adjusted every 5 to 20 degrees, to perform polarized Raman detection.

4. The Raman spectroscopy detection method for vanadium-doped transition metal chalcogenides based on characteristic peaks induced by vanadium doping as described in claim 3, characterized in that, In step 4, the rotation angle of the half-glass slide is set to θ. max A mapping scan was performed and processed to obtain the polarization mapping spectrum of vanadium-doped two-dimensional transition metal chalcogenides at the angle θmax; a mapping scan was performed with the half-slide rotation angle set to θmin, and the spectrum was processed to obtain θ min Polarized Raman mapping spectra of vanadium-doped two-dimensional transition metal chalcogenides at an angle; based on the aforementioned θ max Angular polarization Raman mapping and the θ min The distribution of colors in two spectra from the angular polarization Raman mapping is used to determine the doping concentration distribution.

5. The Raman spectroscopic detection method for vanadium-doped transition metal chalcogenides based on characteristic peaks induced by vanadium doping as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Raman spectroscopy detection: The growth substrate loaded with vanadium-doped transition metal chalcogenide grown by chemical vapor deposition is placed on the Raman spectrometer test platform. The sample to be tested is focused by an optical microscope and the Raman spectrum is obtained by laser confocal Raman spectroscopy detection. S2. Raman Spectrum Processing: The Raman spectrum is processed, a baseline is set, and the peak positions of the vanadium-doped transition metal chalcogenides are calibrated based on the Raman peaks of the growth substrate material. The characteristic peaks of the vanadium-doped transition metal chalcogenides are determined, and the characteristic peaks are fitted and analyzed to determine their peak positions, peak intensities, and full width at half maximum (FWHM). Charge transfer and stress are calculated based on peak position shifts, and the electron-phonon coupling strength is determined based on the FWHM to determine the concentration distribution of vanadium doping. S3. Mapping Scan: Perform a mapping scan on the vanadium-doped transition metal sulfide sheets to be detected. The mapping scan range is set to be within 50 cm of the characteristic peak described in S2. -1 -100cm -1 The range is used to obtain the mapping map; S4. Mapping image processing: The mapping image obtained in S3 is processed to remove noise, the intensity range of the image is set according to the baseline and peak intensity obtained from the test, the color scheme of the image display is set, the color uniformity in the Raman mapping image is analyzed, and the uniformity of the vanadium doping concentration distribution is determined. S5. Polarization Raman Detection: A polarization optical component is added to the test optical path of the Raman spectrometer. By adjusting the rotation angle θ of the 1 / 2 glass slide in the polarization optical component, polarization Raman detection is performed on the sample to be tested to determine the uniformity of the vanadium doping concentration distribution.

6. The Raman spectroscopy detection method for vanadium-doped transition metal chalcogenides based on characteristic peaks induced by vanadium doping as described in claim 5, characterized in that, In S1, the magnification range of the optical microscope is 50-1500x; the detection conditions for the laser confocal Raman spectroscopy are: laser wavelength 266nm-1064nm, laser intensity attenuation 0.1%-100%, integration time 0.1s-100s, integration times 1-10, and Raman spectroscopy testing range 100cm. -1 -1000cm -1 .

7. The Raman spectroscopy detection method for vanadium-doped transition metal chalcogenides based on characteristic peaks induced by vanadium doping as described in claim 5, characterized in that, In S2, charge transfer and stress are calculated based on peak position shift, doping concentration is calculated based on peak intensity, and electron-phonon coupling strength is determined based on full width at half maximum (FWHM) and a database is established.

8. The Raman spectroscopy detection method for vanadium-doped transition metal chalcogenides based on characteristic peaks induced by vanadium doping as described in claim 5, characterized in that, In S3, the excitation laser wavelength is consistent with the Raman test wavelength described above, the laser intensity attenuation is 0.1%-100%, and the scan time integration time is 0.1%. -1 The number of integrations is 1-5, and the scanning test step size is 0.1μm-5μm.

9. The Raman spectroscopy detection method for vanadium-doped transition metal chalcogenides based on characteristic peaks induced by vanadium doping as described in claim 5, characterized in that, In S1, the growth substrate material is a silicon wafer, quartz, or mica with a silicon oxide layer.

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