A high-efficiency and high-resolution device for realizing reflective electron spectroscopy

Abstract

The present invention provides a highly efficient and high-resolution device for realizing a reflected photoelectron energy spectrum, characterized in that it comprises a vacuum chamber, a vacuum pumping device, an electron generating and emitting device, a sample fixing device, a photon collecting and transmitting device, and a high-resolution grating spectrometer; one end of the electron generating and emitting device is inserted into the vacuum chamber; the vacuum pumping device is connected to the vacuum chamber; one end of the sample fixing device is in the vacuum chamber; the high-resolution grating spectrometer is arranged on the photon collecting and transmitting device. A highly efficient and high-resolution device for realizing a reflected photoelectron energy spectrum, wherein the high-resolution grating spectrometer is replaced with a deep ultraviolet narrow-band filter and a photon energy detector; the deep ultraviolet narrow-band filter and the photon energy detector are connected. The beneficial effects of the present invention are that it can more efficiently collect photons generated by the reflected photoelectron effect, and effectively improve the resolution of the system.

Description

Technical Field

[0001] The invention relates to the field of material physics energy spectrum analysis instruments, and in particular to a high-efficiency and high-resolution reflective electron energy spectrum realization device. Background Art

[0002] The electronic structure of materials directly determines the thermal, optical, electrical transport and other physical properties of materials. It is the key research object of materials science, condensed matter physics and other disciplines. It is also crucial to the application of materials. In particular, the performance of a large number of electronic devices is closely related to the conduction band and valence band structure of their materials. Therefore, it is very important to accurately measure the electronic structure of materials. Suitable materials can greatly improve the performance of electronic devices and broaden the application range of instruments.

[0003] Photoelectron spectroscopy is a widely used method for accurately measuring the electronic structure of materials, and has achieved remarkable results. Using the principle of the photoelectric effect, the kinetic energy, photoelectron intensity and angular distribution of photoelectrons emitted from a sample by monochromatic light radiation are measured, and this information is used to study the electronic structure of atoms, molecules, condensed phases, and especially solid surfaces. A large amount of work has focused on the use of X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy to study the valence band electronic band structure and work function information. However, since the electrons of the material itself are generally in the valence band, photoelectron spectroscopy cannot directly study the energy level structure of the conduction band, and the energy level structure information of the conduction band is crucial to the performance of the entire electronic device. There is an urgent need for a way to directly measure the conduction band structure in real time.

[0004] The inverse photoelectron spectroscopy technique can make up for the shortcomings of the photoelectron spectroscopy and can be directly used to measure the electronic structure of the conduction band of the material. The basic physical process of the inverse photoelectron spectroscopy is opposite to the photoelectric effect. Free electrons with a specific kinetic energy are incident on the surface of the material, compounded into the energy level of the conduction band of the material, and then transitioned downward to the energy level of another conduction band. This transition process satisfies the principles of dipole transition, conservation of energy, and conservation of momentum at the same time. Therefore, by measuring the photon spectrum excited by the electrons, the electronic structure of the unoccupied conduction band of the solid can be obtained.

[0005] According to different experimental methods of reflected photoelectron emission, reflected photoelectron spectroscopy is mainly divided into angle-resolved reflected photoelectron spectroscopy and spin-resolved reflected photoelectron spectroscopy, etc. Angle-resolved reflected photoelectron spectroscopy determines the band dispersion relation curve of the material by changing the angle between the incident electron beam and the sample normal; spin-resolved reflected photoelectron spectroscopy polarizes the incident electrons and can directly measure the spin information of holes in the conduction band electronic energy level. According to the type of photon detector, it can be divided into two working modes: spectral spectrometry and monochromatic measurement mode. Spectral spectrometry fixes the kinetic energy of the incident electron, analyzes the energy spectrum of the emitted photons through the grating, and then uses an electron multiplier tube to count photons; the monochromatic measurement mode changes the kinetic energy of the incident electron and uses a very narrow energy bandwidth ultraviolet photon Geiger detector to measure the photons excited by the electron.

[0006] Taking the development of organic solar cells as an example, a comprehensive and accurate understanding of the interface energy level structure of the heterojunction will enable the adjustment of the interface energy level of organic molecules and inorganic electrode materials, thereby optimizing the carrier transmission and the transport process at the electrode interface, optimizing the electron-hole separation process in the photovoltaic effect, and thus greatly improving its energy conversion efficiency. The reflected electron energy spectrum is an effective means to study the conduction band energy level structure.

[0007] However, the effective cross section of the reflected photoelectron energy spectrum is much smaller than that of the photoelectron energy spectrum, so its development and application are more difficult and far behind the photoelectron energy spectrum. For example, in the energy range of vacuum ultraviolet light, the effective cross section of the reflected photoelectron energy spectrum is nearly 10 times that of the photoelectron energy spectrum. -5 The energy resolution of commercial photoelectron spectrometers is generally greater than 0.5 eV, and the resolution achieved in foreign laboratories is still higher than 0.12 eV. A change in the conduction band electronic structure of 0.1 eV may lead to an order of magnitude difference in energy transfer efficiency.

[0008] Therefore, the market is in urgent need of a device for realizing a reflective photoelectron energy spectrum that can more efficiently collect photons generated by the reflective photoelectron effect and effectively improve the resolution of the system. Summary of the invention

[0009] In order to solve the above technical problems, the present invention discloses a highly efficient and high-resolution reflective electron energy spectrum realization device, and the technical solution of the present invention is implemented as follows:

[0010] A highly efficient and high-resolution reflective electron energy spectrum realization device, characterized in that it includes a vacuum cavity, a vacuum pumping device, an electron generating and emitting device, a sample fixing device, a photon collecting and transmitting device and a high-resolution grating spectrometer; one end of the electron generating and emitting device is inserted into the vacuum cavity; the vacuum pumping device is connected to the vacuum cavity; one end of the sample fixing device is in the vacuum cavity; and the high-resolution grating spectrometer is arranged on the photon collecting and transmitting device.

[0011] Preferably, the photon collection and transmission device is elliptical; the inner surface of the photon collection and transmission device is polished.

[0012] Preferably, the material of the photon collection and transmission device is selected from one of gold, silver and copper.

[0013] Preferably, the photon collection and transmission device has a major axis of 200-700 mm and a minor axis of 4-20 mm.

[0014] Preferably, it also includes a length adjustment device and an angle adjustment device; the length adjustment device and the angle adjustment device are located at the connection between the high-resolution grating spectrometer and the photon collection and transmission device; one end of the angle adjustment device is fixed to the photon collection and transmission device, and the other end of the angle adjustment device is fixed to one end of the length adjustment device; the other end of the length adjustment device is fixed to the high-resolution grating spectrometer.

[0015] Preferably, the high-resolution grating spectrometer is replaced by a deep ultraviolet narrow-band filter and a photon energy detector; the deep ultraviolet narrow-band filter and the photon energy detector are connected.

[0016] Preferably, the deep ultraviolet narrow-band filter comprises an upper reflection film system and a lower reflection film system; the lower reflection film system comprises a substrate, a lower type of film layer and a lower second type of film layer; the lower type of film layer and the lower second type of film layer are alternately plated on the substrate; the number of the lower type of film layer and the lower second type of film layer is 20-25 layers in total; the upper reflection film system comprises a resonant cavity layer, an upper type of film layer and an upper second type of film layer; the upper type of film layer and film layers are alternately plated on the resonant cavity layer; the number of the film layers and the upper type of film layers is 20-25 layers in total; the thickness of the upper type of film layer and the lower type of film layer is one quarter of the quotient obtained by dividing the required wavelength by the refractive index of the materials of the upper type of film layer and the lower type of film layer at the wavelength; the thickness of the upper second type of film layer and the lower second type of film layer is one quarter of the quotient obtained by dividing the required wavelength by the refractive index of the materials of the upper type of film layer and the lower type of film layer at the wavelength.

[0017] Preferably, the material of the substrate and the resonant cavity layer is magnesium fluoride.

[0018] Preferably, the upper film layer and the lower film layer are magnesium fluoride; the upper second film layer and the lower second film layer are calcium fluoride.

[0019] Preferably, the structure of the photon energy detector is selected from one of a Geiger-Muller counter tube and a photomultiplier tube.

[0020] The implementation of the technical solution of the present invention can solve the technical problems of inefficient collection of photons generated by the reflective electron effect and insufficient system resolution in the prior art; the implementation of the technical solution of the present invention can achieve the technical effect of more efficient collection of photons generated by the reflective electron effect and effectively improve the resolution of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a spectrum spectroscopic state diagram of a highly efficient and high-resolution reflective electron energy spectrum realization device;

[0023] Figure 2 A state diagram of a monochromatic measurement mode of a device for realizing high-efficiency and high-resolution reflected photoelectron energy spectrum;

[0024] Figure 3 This is an enlarged view of a deep ultraviolet narrow-band filter of a device for realizing a high-efficiency and high-resolution reflective electron energy spectrum;

[0025] Figure 4 The transmission curve of a deep ultraviolet narrow-band filter for a high-efficiency and high-resolution reflective electron spectrum realization device;

[0026] Figure 5 A state diagram of a removal length adjustment device for a high-efficiency and high-resolution reflective electron energy spectrum realization device;

[0027] Figure 6 The present invention is a state diagram of a removal length adjustment device and an angle adjustment device for a high-efficiency and high-resolution reflective electron energy spectrum realization device.

[0028] In the above drawings, the figure numbers represent:

[0029] 1-vacuum cavity, 2-vacuum pumping device, 3-electron generation and emission device, 4-sample fixing device, 5-photon collection and transmission device, 6-length adjustment device, 7-angle adjustment device, 8-high-resolution grating spectrometer, 9-deep ultraviolet narrow-band filter, 10-photon energy detector, 11-upper reflection film system, 12-resonance cavity layer, 13-lower reflection film system, 14-substrate. DETAILED DESCRIPTION

[0030] 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.

[0031] In a specific embodiment, Figure 1-Figure 6 As shown, a high-efficiency and high-resolution reflective electron energy spectrum realization device is characterized in that it includes a vacuum cavity 1, a vacuum pumping device 2, an electron generating and emitting device 3, a sample fixing device 4, a photon collecting and transmitting device 5 and a high-resolution grating spectrometer 8; one end of the electron generating and emitting device 3 is inserted into the vacuum cavity 1; the vacuum pumping device 2 is connected to the vacuum cavity 1; one end of the sample fixing device 4 is in the vacuum cavity 1; the high-resolution grating spectrometer 8 is arranged on the photon collecting and transmitting device 5.

[0032] In this specific embodiment, when in use, the target sample is placed on the sample fixing device 4 and then the sample fixing device 4 is installed inside the vacuum chamber 1, and then the vacuum pumping device 2 is used to pump the vacuum chamber 1 to a vacuum state above 1e-6mbar, and then the electron generating emission device 3 is used to hit the free electron beam on the surface of the target sample, and the photon collection and transmission device 5 is used to collect the photons generated on the sample, and finally the collected photons are separated and detected by a high-resolution grating spectrometer 8, so as to accurately obtain the frequency and energy distribution of the photons, and finally achieve the design goal of obtaining the electronic structure energy level of the sample; through the interaction between the above modules, it is possible to more efficiently collect photons generated by the anti-photoelectron effect, and effectively improve the resolution of the photon collection process.

[0033] In a preferred embodiment, Figure 1-Figure 6 As shown, the photon collecting and transmitting device 5 is elliptical; the inner surface of the photon collecting and transmitting device 5 is polished.

[0034] In this preferred embodiment, the device is set to an elliptical shape so that photons passing through one focus of the ellipse can reach another focus after being reflected by the inner wall, thereby greatly improving the transmission efficiency of photons over long distances; the polishing treatment makes the inner surface as smooth as possible to improve the controllability of the direction of photon movement.

[0035] In a preferred embodiment, Figure 1-Figure 6 As shown, the material of the photon collection and transmission device 5 is selected from one of gold, silver and copper.

[0036] In this preferred embodiment, the material of the photon collection and transmission device 5 is selected according to the reflectivity of the selected photon frequency, and generally gold, silver, copper, or other materials with high reflectivity may be selected.

[0037] In a preferred embodiment, Figure 1-Figure 6 As shown, the long axis of the photon collection and transmission device 5 is 200-700 mm, and the short axis length is 4-20 mm.

[0038] In this preferred embodiment, a corresponding combination of long and short axes is selected according to actual needs to meet corresponding requirements.

[0039] In a preferred embodiment, Figure 1-Figure 6 As shown, it also includes a length adjustment device 6 and an angle adjustment device 7; the length adjustment device 6 and the angle adjustment device 7 are located at the connection between the high-resolution grating spectrometer 8 and the photon collecting and transmitting device 5; one end of the angle adjustment device 7 is fixed to the photon collecting and transmitting device 5, and the other end of the angle adjustment device 7 is fixed to one end of the length adjustment device 6; the other end of the length adjustment device 6 is fixed to the high-resolution grating spectrometer 8.

[0040] In this preferred embodiment, the photons are transmitted to the high-resolution grating spectrometer 8 through the length adjustment device 6 and the angle adjustment device 7; the length adjustment device 6 and the angle adjustment device 7 change the length and angle to achieve the distance and angle between the photon collection and transmission device 5 and the sample, so as to further improve the photon collection efficiency.

[0041] In a specific embodiment, Figure 1-Figure 6 As shown, the high-resolution grating spectrometer 8 is replaced by a deep ultraviolet narrow-band filter 9 and a photon energy detector 10; the deep ultraviolet narrow-band filter 9 and the photon energy detector 10 are connected.

[0042] In this specific embodiment, its function is to perform monochromatic measurement. The deep ultraviolet narrow-band filter 9 is used to decompose photons, so that photons of a specific wavelength can pass through, but photons of other wavelengths cannot pass through. The overall bandwidth of the deep ultraviolet narrow-band filter 9 is less than or equal to 50 meV. The photons filtered by the deep ultraviolet narrow-band filter 9 enter the photon energy detector 10, and then the photon energy detector 10 analyzes the photons to obtain corresponding results. Figure 4 It can be seen from the transmission curve that the photons generated by the reflective electron effect can be collected more efficiently, effectively improving the resolution of the photon collection process.

[0043] In a preferred embodiment, Figure 1-Figure 6 As shown, the deep ultraviolet narrow-band filter 9 includes an upper reflection film system 11 and a lower reflection film system 13; the lower reflection film system 13 includes a substrate 14, a lower type of film layer and a lower second type of film layer; the lower type of film layer and the lower second type of film layer are alternately plated on the substrate 14; the number of the lower type of film layer and the lower second type of film layer is 20-25 layers in total; the upper reflection film system 11 includes a resonant cavity layer 12, an upper type of film layer and an upper second type of film layer; the upper type of film layer and film layers are alternately plated on the resonant cavity layer 12; the number of the film layers and the upper type of film layers is 20-25 layers in total.

[0044] In this preferred embodiment, the substrate 14, the resonant cavity layer 12, the upper film layer, the lower film layer, the upper second film layer and the lower second film layer are formed by deposition through a vacuum coating method; the lower film layer and the upper film layer are high refractive index film layers, and the lower second film layer and the upper second film layer are low refractive index film layers. Through this arrangement, the variation in spectral shift caused by photons at different incident angles incident on the deep ultraviolet narrow-band filter 9 can be reduced, thereby improving the transmission efficiency of photons. Generally, the transmission efficiency of photons is best when the number of layers is between 20 and 25; after passing through the lower reflective film, the power of the photons will face a certain attenuation, and then pass through the resonant cavity layer 12, where the power is enhanced by the resonant cavity layer 12, thereby enhancing the recognition efficiency of the photon energy detector 10.

[0045] In a preferred embodiment, Figure 1-Figure 6 As shown, the thickness of the upper film layer and the lower film layer is one-fourth of the quotient obtained by dividing the required wavelength by the refractive index of the material of the upper film layer and the lower film layer at the wavelength; the thickness of the upper two film layers and the lower two film layers is one-fourth of the quotient obtained by dividing the required wavelength by the refractive index of the material of the upper film layer and the lower film layer at the wavelength.

[0046] In this preferred embodiment, the high refractive index film layer and the low refractive index film layer are deposited by a vacuum coating method, and the incident light is reflected at the upper and lower interfaces of the film layer with the same phase change. If the optical thickness of the film layer is selected to be equal to one-fourth of the wavelength of the incident light, the phase difference between two adjacent reflected light beams is exactly 2. The result of superposition of all reflected lights can achieve reflection cancellation, thereby forming transmission enhancement. Therefore, the thickness of the upper type of film layer and the lower type of film layer is one-fourth of the quotient obtained by dividing the required wavelength by the refractive index of the material of the upper type of film layer and the lower type of film layer at the wavelength, and the thickness of the upper two types of film layers and the lower two types of film layers is one-fourth of the quotient obtained by dividing the required wavelength by the refractive index of the material of the upper type of film layer and the lower type of film layer at the wavelength, thereby enhancing the transmission effect.

[0047] In a preferred embodiment, Figure 1-Figure 6 As shown, the material of the substrate 14 and the resonant cavity layer 12 is magnesium fluoride; the upper type of film layer and the lower type of film layer are magnesium fluoride; the upper second type of film layer and the lower second type of film layer are calcium fluoride.

[0048] In this preferred embodiment, the extinction coefficients of calcium fluoride and magnesium fluoride in the ultraviolet band enable magnesium fluoride and calcium fluoride to be used as optical film materials in the deep ultraviolet band. At the same time, the refractive index of calcium fluoride is higher than that of magnesium fluoride, so they are used as products of high refractive index layer and low refractive index layer respectively.

[0049] In a preferred embodiment, Figure 1-Figure 6 As shown, the structure of the photon energy detector 10 is selected from one of a Geiger-Muller counter tube and a photomultiplier tube.

[0050] It should be pointed out that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A highly efficient and high-resolution reflective electron spectrum realization device, characterized in that: It includes a vacuum chamber, a vacuum pumping device, an electron generating and emitting device, a sample fixing device, a photon collecting and transmitting device, a high-resolution grating spectrum analysis instrument, a length adjusting device and an angle adjusting device; One end of the electron generating and emitting device is inserted into the vacuum chamber; The vacuum pumping device is connected to the vacuum chamber; One end of the sample fixing device is in the vacuum chamber; the high-resolution grating spectrum analysis instrument is arranged on the photon collection and transmission device; The photon collection and transmission device is elliptical; The length adjustment device and the angle adjustment device are located at the connection between the high-resolution grating spectrum analysis instrument and the photon collection and transmission device; One end of the angle adjustment device is fixed on the photon collection and transmission device, and the other end of the angle adjustment device is fixed on one end of the length adjustment device; the other end of the length adjustment device is fixed on the vacuum cavity.

2. The device for realizing high-efficiency and high-resolution reflected photoelectron energy spectrum according to claim 1, characterized in that: The inner surface of the photon collection and transmission device is polished.

3. The device for realizing high-efficiency and high-resolution reflected photoelectron energy spectrum according to claim 2, characterized in that: The material of the photon collection and transmission device is selected from one of gold, silver and copper.

4. The device for realizing high-efficiency and high-resolution reflected photoelectron energy spectrum according to claim 3, characterized in that: The photon collection and transmission device has a major axis of 200-700 mm and a minor axis of 4-20 mm.

5. A highly efficient and high-resolution reflective electron energy spectrum realization device according to any one of claims 1 to 4, characterized in that: The high-resolution grating spectrum analysis instrument is replaced by a deep ultraviolet narrow-band filter and a photon energy detector; the deep ultraviolet narrow-band filter and the photon energy detector are connected.

6. The device for realizing high-efficiency and high-resolution reflected photoelectron energy spectrum according to claim 5, characterized in that: The deep ultraviolet narrow-band filter comprises an upper reflection film system and a lower reflection film system; The lower reflective film system comprises a substrate, a lower type of film layer and a lower second type of film layer; the lower type of film layer and the lower second type of film layer are alternately plated on the substrate; the number of the lower type of film layer and the lower second type of film layer is 20-25 layers in total; The upper reflective film system includes a resonant cavity layer, an upper type of film layer and an upper second type of film layer; the upper type of film layer and the film layer are alternately plated on the resonant cavity layer; the number of the film layer and the upper type of film layer is 20-25 layers in total; The thickness of the upper type of film layer and the lower type of film layer is one quarter of the quotient obtained by dividing the required wavelength by the refractive index of the materials of the upper type of film layer and the lower type of film layer at the wavelength; The thickness of the upper two types of film layers and the lower two types of film layers is one quarter of the quotient obtained by dividing the required wavelength by the refractive index of the materials of the upper type of film layers and the lower type of film layers at the wavelength.

7. The device for realizing high-efficiency and high-resolution reflected photoelectron energy spectrum according to claim 6, characterized in that: The substrate and the resonant cavity layer are made of magnesium fluoride.

8. The device for realizing high-efficiency and high-resolution reflected photoelectron energy spectrum according to claim 7, characterized in that: The upper film layer and the lower film layer are magnesium fluoride; the upper second film layer and the lower second film layer are calcium fluoride.

9. The device for realizing high-efficiency and high-resolution reflected photoelectron energy spectrum according to claim 8, characterized in that: The structure of the photon energy detector is selected from one of a Geiger-Muller counter tube and a photomultiplier tube.

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