A pressure measurement method based on silicon carbide Raman signal

Abstract

The present invention relates to the field of pressure measurement technology, and discloses a pressure measurement method based on silicon carbide Raman signals, comprising the following steps: providing silicon carbide, and placing the silicon carbide at a pressure position to be measured; laser irradiating the silicon carbide at the pressure position to be measured to form a Raman signal; and calculating the pressure value at the pressure position to be measured according to the Raman shift at the peak of the TO mode or LO mode in the Raman signal. The pressure measurement method of the present invention, which calculates the pressure value at the pressure position to be measured based on the Raman shift at the peak of the TO mode or LO mode, has high measurement accuracy and is more practical; and under variable temperature conditions, the very high thermal conductivity of silicon carbide can reduce errors, no special X-ray protection is required, and there is no peak overlap, so the pressure calculation is more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure measurement, and in particular to a pressure measurement method based on silicon carbide Raman signals. Background Art

[0002] At present, the methods for measuring pressure (0-50GPa) in geological or deep-sea exploration research mainly use the relationship between the fluorescence peak position of ruby ​​and pressure or the state equation of minerals such as magnesium oxide. Ruby has very strong and sharp fluorescence peaks R1 and R2. The peak positions of R1 and R2 are sensitive to pressure, but corrections need to be made under high pressure or temperature changes, which leads to uncertainty in pressure measurement.

[0003] The R1 and R2 fluorescence peaks of ruby ​​under high pressure will gradually overlap, making it difficult to obtain the accurate peak position, resulting in a high calibration error; the equation of state of materials such as magnesium oxide needs to be determined by X-ray diffraction, which is more complicated in experiment and data processing and is radioactive; these two methods need to use knowledge of temperature and material thermal expansion coefficient to simplify the measurement results when the temperature changes rapidly, so these two methods have uncertainty and error in pressure measurement. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems of uncertainty and error in existing pressure measurement methods, and to provide a pressure measurement method based on silicon carbide Raman signals.

[0005] In order to achieve the above object, the present invention provides a pressure measurement method based on silicon carbide Raman signal, comprising the following steps:

[0006] Providing silicon carbide, and placing the silicon carbide at a pressure position to be measured;

[0007] irradiating the silicon carbide at the pressure position to be measured with laser to form a Raman signal;

[0008] The pressure value at the pressure position to be measured is calculated according to the Raman shift at the peak position of the TO mode or the LO mode in the Raman signal.

[0009] As an implementable embodiment, the step of calculating the pressure value at the pressure position to be measured based on the Oman shift at the peak of the TO mode or LO mode in the Raman signal specifically includes: calculating the pressure value at the pressure position to be measured based on the Raman shift at the highest peak of the TO mode or LO mode in the Raman signal.

[0010] As an implementation method, the silicon carbide is any one of 3C silicon carbide, 4H silicon carbide, and 6H silicon carbide.

[0011] As an implementation method, when the silicon carbide is 4H silicon carbide, the calculation formula for calculating the pressure value at the pressure position to be measured according to the peak value of the TO mode in the Raman signal is: ω TO (cm -1 )=778.24(48)+3.41(5)*P-0.014(1)*P 2 , where P represents the pressure value at the pressure position to be measured, ω TO (cm -1 ) represents the Raman shift at the highest peak of the peak position of the TO mode at the pressure position to be measured.

[0012] As an implementation method, when the silicon carbide is 4H silicon carbide, the calculation formula for calculating the pressure value at the pressure position to be measured according to the peak value of the LO mode in the Raman signal is: ω LO (cm -1 )=961.28(108)+4.69(12)*P-0.026(2)*P 2 , where P represents the pressure value at the pressure position to be measured, ω LO (cm -1 ) represents the Raman shift at the highest peak of the peak position of the LO mode at the pressure position to be measured.

[0013] As an implementable embodiment, the Raman signal formed after the silicon carbide located at the pressure position to be measured is irradiated with laser by a spectrometer is collected.

[0014] Beneficial effects of the present invention: The pressure measurement method based on silicon carbide Raman signals provided by the present invention calculates the pressure value at the pressure position to be measured according to the Raman shift at the peak of the TO mode or LO mode in the Raman signal, has high measurement accuracy and is more practical; and under variable temperature conditions, the very high thermal conductivity of silicon carbide can reduce errors, no special X-ray protection is required, and there is no peak overlap, so the pressure calculation is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the steps of a pressure measurement method based on silicon carbide Raman signals according to an embodiment of the present invention.

[0016] Figure 2 Schematic diagram of the peak positions of TO mode and LO mode of Raman signal formed by laser irradiation of 4H silicon carbide in the pressure measurement method based on silicon carbide Raman signal in an embodiment of the present invention.

[0017] Figure 3This is a schematic diagram of the change of the Raman shift at the highest peak of the TO mode and LO mode peaks obtained by testing 4H silicon carbide at different pressure values ​​in the pressure measurement method based on silicon carbide Raman signal in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] See also Figure 1 This embodiment provides a technical solution, a pressure measurement method based on silicon carbide Raman signals, comprising the following steps:

[0020] Step S100, providing silicon carbide, and placing the silicon carbide at a pressure position to be measured;

[0021] Step S200, irradiating the silicon carbide at the pressure position to be measured with laser to form a Raman signal;

[0022] Step S300: Calculate the pressure value at the pressure position to be measured according to the Raman shift at the peak position of the TO mode or the LO mode in the Raman signal.

[0023] The step of calculating the pressure value at the pressure position to be measured according to the Raman shift at the peak position of the TO mode or LO mode in the Raman signal specifically includes: calculating the pressure value at the pressure position to be measured according to the Raman shift at the highest peak value of the peak position of the TO mode or LO mode in the Raman signal.

[0024] The silicon carbide may be 3C silicon carbide, 4H silicon carbide, 6H silicon carbide, etc., which has TO mode and LO mode in the Raman signal generated when subjected to laser irradiation. This embodiment does not impose any limitation, and this embodiment also has no limitation on the shape of the silicon carbide.

[0025] When the silicon carbide is 4H silicon carbide, the calculation formula for calculating the pressure value at the pressure position to be measured according to the peak value of the TO mode in the Raman signal is: ω TO (cm -1 )=778.24(48)+3.41(5)*P-0.014(1)*P 2 , where P represents the pressure value at the pressure position to be measured, ω TO (cm -1) represents the Raman shift at the highest peak of the peak position of the TO mode at the pressure position to be measured.

[0026] When the silicon carbide is 4H silicon carbide, the calculation formula for calculating the pressure value at the pressure position to be measured according to the peak value of the LO mode in the Raman signal is: ω LO (cm -1 )=961.28(108)+4.69(12)*P-0.026(2)*P 2 , where P represents the pressure value at the pressure position to be measured, ω LO (cm -1 ) represents the Raman shift at the highest peak of the peak position of the LO mode at the pressure position to be measured.

[0027] Wherein, the Raman signal formed after the silicon carbide located at the pressure position to be measured is irradiated with laser by a spectrometer is collected.

[0028] Specifically, Figure 2 The figure shows the change in the signal intensity of the Raman signal at a certain pressure value when 4H silicon carbide is used. The horizontal coordinate Raman shift (cm -1 ) represents the Raman shift, and the vertical axis Intensity (Counts) represents the signal intensity. It can be seen that the peaks of the TO mode and the LO mode are the most obvious, that is, the TO mode and the LO mode are most sensitive to pressure. Therefore, in order to verify the relationship between the pressure value and the Raman shift at the highest peak of the TO mode or LO mode in the Raman signal, as shown in Figure 3 The following are the pressure test data based on 4H silicon carbide and the pressure relief test data based on 4H silicon carbide, respectively. The horizontal axis Pressure (GPa) represents the pressure value, and the vertical axis Raman shift (cm -1 ) represents Raman shift; by measuring the Raman spectrum of the 0001 crystal plane of 4H silicon carbide, it can be seen that, whether pressurized or unpressurized, the Raman shift at the highest peak of the TO mode or the LO mode respectively shows a certain regular rise and fall. Therefore, through the experimental parameters, this embodiment obtains a calculation method for calculating the pressure value based on the Raman shift at the highest peak of the TO mode and the LO mode when using 4H silicon carbide for pressure testing. In the process of each actual need to calculate the pressure value at the pressure position to be measured, it is only necessary to read the x value at the highest point of the TO mode or LO peak, that is, the Raman shift and record it, and substitute it into the formula to calculate the pressure value. Of course, in other embodiments, other crystal forms of silicon carbide can also be used to conduct experiments to obtain the calculation formula and ultimately use it for pressure calculation, which will not be repeated in this embodiment.

[0029] Compared with the prior art, the technical solution provided in this embodiment has better effects and more practical significance. Moreover, under variable temperature conditions, the very high thermal conductivity of silicon carbide can reduce errors, no special X-ray protection is required, and there is no peak overlap. The pressure calculation is more accurate and better results are achieved.

[0030] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A pressure measurement method based on silicon carbide Raman signals, characterized in that: The following steps are involved: Providing silicon carbide, and placing the silicon carbide at a pressure position to be measured; irradiating the silicon carbide at the pressure position to be measured with laser to form a Raman signal; Calculating the pressure value at the pressure position to be measured according to the Raman shift at the peak position of the TO mode or the LO mode in the Raman signal; When the silicon carbide is 4H silicon carbide, the calculation formula for calculating the pressure value at the pressure position to be measured according to the Raman shift at the highest peak of the peak position of the TO mode in the Raman signal is: , where P represents the pressure value at the pressure position to be measured, represents the Raman shift at the highest peak of the peak position of the TO mode at the pressure position to be measured; When the silicon carbide is 4H silicon carbide, the calculation formula for calculating the pressure value at the pressure position to be measured according to the Raman shift at the highest peak of the LO mode peak in the Raman signal is: , where P represents the pressure value at the pressure position to be measured, It represents the Raman shift at the highest peak of the peak position of the LO mode at the pressure position to be measured.

2. The pressure measurement method based on silicon carbide Raman signal according to claim 1 is characterized in that: The step of calculating the pressure value at the pressure position to be measured according to the Raman shift at the peak position of the TO mode or LO mode in the Raman signal specifically includes: calculating the pressure value at the pressure position to be measured according to the Raman shift at the highest peak value of the peak position of the TO mode or LO mode in the Raman signal.

3. The pressure measurement method based on silicon carbide Raman signal according to claim 1 is characterized in that: The silicon carbide is any one of 3C silicon carbide, 4H silicon carbide and 6H silicon carbide.

4. The pressure measurement method based on silicon carbide Raman signal according to claim 1 is characterized in that: The Raman signal formed after the silicon carbide located at the pressure position to be measured is irradiated with laser is collected by a spectrometer.

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