Si-doped epsilon-Ga2O3 material with high conductivity and deep ultraviolet light absorption performance and preparation method of Si-doped epsilon-Ga2O3 material

Abstract

The invention relates to the technical field of semiconductor materials, and discloses a Si-doped epsilon-Ga2O3 material with high conductivity and deep ultraviolet light absorption performance and a preparation method, the doping concentration of Si in the Si-doped epsilon-Ga2O3 material is 0.83 at%-2.5 at%, and Si atoms replace tetrahedral coordinated Ga (1) atoms in epsilon-Ga2O3. By accurately controlling the Si doping concentration to be 0.83-2.5 at% and enabling Si atoms to replace tetrahedral coordinated Ga (1) atoms in epsilon-Ga2O3, the electronic structure of the material is effectively improved, the Fermi level moves upwards to enter a conduction band after Si doping, and Si3s orbital electrons occupy the conduction band bottom (CBM), so that the carrier concentration is increased, the effective mass of the electrons is reduced, and the conductivity of the material is remarkably improved; tests show that compared with an intrinsic epsilon-Ga2O3 material, the conductivity of the doped material is improved by 1-3 orders of magnitude, strict requirements of high-power electronic components and the like on the conductivity of the material are met, heat loss of the electronic components due to resistance is reduced, and the working efficiency and stability of the components are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor materials, and particularly relates to an Si-doped ε-Ga2O3 material with high electrical conductivity and deep ultraviolet light absorption performance and a preparation method thereof. Background Art

[0002] In the development process of semiconductor materials, the third-generation semiconductors have become a hot research field due to their unique physical and chemical properties. As a metastable phase in the gallium oxide family with stability second only to β-Ga2O3, ε-Ga2O3 shows great potential in many application scenarios.

[0003] In terms of high-power electronic components, with the development of modern power systems towards higher voltage and higher power, higher requirements are put forward for the breakdown electric field strength, thermal conductivity and other properties of semiconductor materials. ε-Ga2O3 has a relatively wide bandgap and theoretically can withstand higher voltages, promising to greatly improve the performance and reliability of high-power electronic components. In the field of fifth-generation communication (5G) radio frequency components, the rapid development of 5G technology requires high-performance radio frequency materials to achieve high-speed and large-capacity data transmission. The high-frequency characteristics of ε-Ga2O3 make it one of the potential candidate materials for 5G radio frequency components. In the aspect of deep ultraviolet photodetection devices, deep ultraviolet light has wide applications in biomedical detection, environmental monitoring, security and other fields. The bandgap structure of ε-Ga2O3 makes it sensitive to deep ultraviolet light, making it possible to develop high-performance deep ultraviolet photodetectors.

[0004] However, the intrinsic ε-Ga2O3 material has a key defect, that is, its electrical conductivity is relatively low. In practical applications, low electrical conductivity will lead to an increase in the resistance of electronic devices, resulting in excessive heat loss, which limits the working efficiency and performance improvement of the devices. For example, in high-power electronic components, if the heat generated by the resistance cannot be dissipated in time, it will cause the temperature of the components to rise, affecting their stability and service life; in 5G radio frequency components, the existence of resistance will reduce the signal transmission efficiency and increase signal loss.

[0005] To solve this problem, element doping technology has become a key focus of researchers. In previous studies, many researchers have explored the doping of ε-Ga2O3 with different elements. The Bardeleben research group used electron paramagnetic resonance technology to analyze the Si-doped epitaxial layer and confirmed that Si can be used as an efficient shallow-level donor dopant, laying the foundation for the study of Si-doped ε-Ga2O3. The Bosio team used oxygen-poor SnO2 sputtering coating combined with thermal diffusion process to dope ε-Ga2O3 with Sn, and successfully controlled the film resistivity to the order of 1Ω·cm, demonstrating the significant effect of doping on the electrical properties of the material. Liu et al. prepared Mg-doped ε-Ga2O3 modified films by magnetron sputtering and metal organic chemical vapor deposition, which showed application value in the field of deep ultraviolet photoelectric sensing.

[0006] Despite the above research results, there are still many problems. On the one hand, there is a lack of systematic and in-depth research on the effects of different Si doping concentrations on the electronic structure, optical properties and other aspects of ε-Ga2O3. Different Si doping concentrations may cause complex changes in the electron distribution and band structure inside the material, which in turn affects the electrical and optical properties of the material, but there is no comprehensive research to reveal these internal connections. On the other hand, there is no mature, stable and precise control of Si doping concentration method for preparing Si-doped ε-Ga2O3 materials with high conductivity and deep ultraviolet light absorption performance. The existing preparation process has deficiencies in the accuracy of doping concentration control and the consistency of material properties, and it is difficult to meet the strict requirements of modern electronic devices for high-performance semiconductor materials. Therefore, the development of a method for preparing ε-Ga2O3 materials that can accurately control the Si doping concentration and prepare ε-Ga2O3 materials with both high conductivity and excellent deep ultraviolet light absorption performance has become an important issue that needs to be solved in the current field of semiconductor materials. Therefore, in view of this, the existing structure and defects are studied and improved, and a Si-doped ε-Ga2O3 material and preparation method with high conductivity and deep ultraviolet light absorption performance is provided, in order to achieve a more practical purpose. Summary of the invention

[0007] To solve the above problems, the present invention provides a Si-doped ε-Ga2O3 material with high electrical conductivity and deep ultraviolet light absorption performance and a preparation method to solve the problems existing in the above background technology.

[0008] The present invention provides the following technical solution: a Si-doped ε-Ga2O3 material with high electrical conductivity and deep ultraviolet light absorption performance, wherein the Si doping concentration in the Si-doped ε-Ga2O3 material is 0.83at%-2.5at%, and Si atoms replace tetrahedrally coordinated Ga(1) atoms in ε-Ga2O3.

[0009] Furthermore, after the material is doped with Si, the Fermi level moves upward into the conduction band, and the electrons in the Si 3s orbital occupy the bottom of the conduction band (CBM).

[0010] Furthermore, the optical band gap of the material increases with the increase of the Si doping concentration, and the average optical absorption edge gradually becomes larger.

[0011] Furthermore, the band gap of the doped material gradually decreases with the increase of the Si doping concentration.

[0012] Furthermore, a preparation method of Si-doped ε-Ga2O3 material with high electrical conductivity and deep ultraviolet light absorption performance is provided, which is characterized by the following steps:

[0013] S1. Construct a calculation model: Determine the initial lattice parameters of ε-Ga2O3 with reference to the experimental values, use the 2×1×1 supercell of ε-Ga2O3, consider four doping structures of Si substituting Ga(1), Ga(2), Ga(3) and Ga(4), and determine that Si tends to substitute Ga(1) atoms to achieve doping by calculating the total energy of different doping structures, so as to construct ε-Ga2O3 models with different Si doping concentrations;

[0014] S2. Optimize parameters by first-principles calculation: Use the CASTEP module of the Materialstudio platform to perform calculations based on the first-principles plane wave pseudopotential method of density functional theory (DFT); adopt periodic boundary conditions, and use the generalized gradient approximation (GGA) and Perdew-Burke-Ernzerhof (PBE) to deal with the exchange-correlation energy; select ultrasoft pseudopotentials to describe the interaction potential between the ion core and valence electrons, and set the valence electron configurations as [Ga]3d 10 4s 2 4p 1 、[O]2s 2 2p 4 、[Si]3s 2 3p 2 ; Adopt the GGA+U method, and set the parameters of Ud,Ga and Up,O to 13.6 eV and 8.3 eV respectively; determine the plane wave cut-off energy to be 450 eV, and set the corresponding Monkhorst-Pack type K-point grid for different unit cells. The 1×1×1 supercell uses a 3×2×2 grid, the 2×1×1 supercell uses a 3×3×3 grid, and the 3×1×1 supercell uses a 2×4×4 grid;

[0015] S3. Material Preparation: According to the optimized parameters above, use molecular beam epitaxy or chemical vapor deposition to prepare Si-doped ε-Ga2O3 material. During the preparation process, strictly control the reaction temperature, gas flow rate, and doping source concentration to ensure that Si atoms uniformly replace the tetrahedrally coordinated Ga(1) atoms in ε-Ga2O3, and the doping concentration is controlled within the range of 0.83 at%-2.5 at%.

[0016] Further, in the step of constructing the calculation model, the calculation formula used for calculating the total energy is: E f = E T (Si x Ga 1-x O3) - E T (Ga2O3) - μ Si + μ Ga , where E T (Si x Ga 1-x O3) is the total energy of the ε-Ga2O3 supercell with different concentrations of Si substitution doping, E T (Ga2O3) is the total energy of the intrinsic ε-Ga2O3 of the same supercell, μ Si is the chemical potential of the Si atoms added to the supercell, and μ Ga is the chemical potential of Ga atoms.

[0017] Further, in the step of optimizing the parameters by first-principles calculation, the LBFGS algorithm is used for structure optimization. Before calculation, full relaxation structure optimization is performed on the atomic coordinates and unit cell volume of the model. The self-consistent optimization parameters include: the energy accuracy is set to 5.0×10 -6 eV / atom; the accuracy of the interatomic interaction force is set to The accuracy of the internal stress in the crystal is set to 0.02 GPa; the accuracy of the maximum atomic displacement is set to When the above four parameters reach or exceed the set accuracy, the structure optimization is completed.

[0018] Further, when using molecular beam epitaxy for preparation, it is carried out in an ultra-high vacuum environment. The substrate is heated to a specific temperature, and Ga, O, and Si sources are evaporated respectively. The target doping concentration is achieved by precisely controlling the evaporation rate of the Si source.

[0019] Further, when using chemical vapor deposition for preparation, by precisely controlling parameters such as the flow rate of the Si-containing compound in the reaction gas, the reaction temperature, and the reaction time, uniform substitution of Si atoms at the positions of tetrahedrally coordinated Ga(1) atoms in ε-Ga2O3 and control of the target doping concentration are achieved.

[0020] The technical effects and advantages of the present invention:

[0021] 1. In the present invention, by precisely controlling the Si doping concentration within 0.83 at% - 2.5 at% and replacing the tetrahedrally coordinated Ga(1) atoms in ε-Ga2O3 with Si atoms, the electronic structure of the material is effectively improved. After Si doping, the Fermi level moves upward into the conduction band, and the electrons in the Si 3s orbitals occupy the conduction band minimum (CBM), increasing the carrier concentration and reducing the effective mass of electrons, thus significantly improving the electrical conductivity of the material. Through testing, compared with the intrinsic ε-Ga2O3 material, the electrical conductivity of the doped material has increased by 1 - 3 orders of magnitude, meeting the strict requirements for the electrical conductivity of high-power electronic components, etc., reducing the heat loss caused by resistance in electronic devices, and improving the working efficiency and stability of the devices.

[0022] 2. The optical bandgap of the material in the present invention increases with the increase of the Si doping concentration, and the average optical absorption edge gradually becomes larger, enhancing the absorption ability of the material for deep ultraviolet light. In the application scenario of deep ultraviolet photodetection devices, when tested with a common deep ultraviolet light source (such as a wavelength of 254 nm), compared with the undoped ε-Ga2O3 material, the light absorption efficiency of the doped material in the present invention has increased by 30% - 50%, showing better application prospects in fields such as deep ultraviolet photodetection devices, and can effectively improve the sensitivity and accuracy of deep ultraviolet light detection.

[0023] 3. The present invention provides theoretical guidance for material preparation by constructing a calculation model and using first-principles calculations to optimize parameters, and determines the optimal preparation conditions. At the same time, during the preparation process, parameters such as reaction temperature, gas flow rate, and doping source concentration are strictly controlled. Whether using molecular beam epitaxy or chemical vapor deposition, it can ensure that Si atoms are uniformly replaced and the doping concentration is accurately controlled within the target range, guaranteeing the stability and consistency of the material properties. Through repeated preparation experiments for verification, the performance differences of materials prepared in different batches are less than 5%, which is conducive to large-scale industrial production.

[0024] 4. The present invention has systematically studied the effects of different Si doping concentrations on the electronic structure, optical properties, etc. of ε-Ga2O3, revealing the internal relationship between the doping concentration and the material properties, filling the relevant research gaps, and providing a theoretical basis for further optimizing the material properties and expanding applications in the future. Based on the research results of the present invention, the synergistic effects of co-doping other elements with Si on the properties of ε-Ga2O3 materials can be further explored in the future, and it is expected to develop semiconductor materials with better performance. Description of the Drawings

[0025] Figure 1 It is a flow chart of the preparation method in the present invention;

[0026] Figure 2In the present invention, the 2×1×1 supercell of ε-Ga2O3 has 4 different Ga positions: tetrahedral Ga(1), pentahedral Ga(2), and two octahedral Ga(3) and Ga(4); Detailed implementation mode

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] It can be understood that the terms "first", "second", etc. used in the present application may be used herein to describe various elements, but unless otherwise specified, these elements are not limited by these terms. These terms are only used to distinguish the first element from another element.

[0029] Example 1: Preparation of ε-Ga2O3 material with Si doping concentration of 0.83 at%

[0030] Construct a calculation model: Refer to the existing accurate experimental data to determine the initial lattice parameters of ε-Ga2O3. Use the 2×1×1 supercell of ε-Ga2O3 and carefully consider the four doping structures of Si substituting Ga(1), Ga(2), Ga(3) and Ga(4). Use professional calculation software to calculate the total energy of different doping structures through complex algorithms. After multiple accurate calculations and comparative analyses, it is determined that Si tends to substitute Ga(1) atoms to achieve doping, thereby constructing an ε-Ga2O3 model with a Si doping concentration of 0.83 at%.

[0031] First-principles calculation to optimize parameters: Open the CASTEP module of the Materialstudio platform and carry out calculation work based on the first-principles plane-wave pseudopotential method of density functional theory (DFT). Set the use of periodic boundary conditions, and use the generalized gradient approximation (GGA) and Perdew-Burke-Ernzerhof (PBE) to deal with the exchange-correlation energy. Select appropriate ultrasoft pseudopotentials to describe the interaction potential between the ion core and valence electrons, and clearly set the valence electron configuration as [Ga]3d 10 4s 2 4p 1 、[O]2s 2 2p 4 、[Si]3s 2 3p 2To accurately obtain the bandgap of ε-Ga2O3, the GGA+U method is adopted, and the parameters of Ud,Ga and Up,O are set to 13.6 eV and 8.3 eV respectively. The plane wave cutoff energy is determined to be 450 eV, and a 3×2×2 Monkhorst-Pack type k-point mesh is set for the 1×1×1 supercell. Before the calculation, the LBFGS algorithm is used to perform full relaxation structural optimization on the atomic coordinates and unit cell volume of the model, and the self-consistent optimization parameters are strictly set: the energy accuracy is set to 5.0×10 -6 eV / atom; the accuracy of the interatomic interaction force is set to The accuracy of the internal stress in the crystal is set to 0.02 GPa; the accuracy of the maximum atomic displacement is set to When all these four parameters reach or exceed the set accuracy, the structural optimization is completed.

[0032] Material preparation (molecular beam epitaxy method): Prepare the ultra-high vacuum equipment, evacuate its internal environment to the ultra-high vacuum state to reduce the interference of external impurities on material preparation. Place the specially treated substrate into the equipment and slowly heat it to 500 °C. Place the high-purity Ga, O, and Si sources in their respective evaporation devices. Turn on the evaporation devices, precisely control the evaporation rate of the Si source through a high-precision flow control system, and at the same time stably control the evaporation amounts of the Ga and O sources to make the doping concentration of Si in ε-Ga2O3 reach 0.83 at%. During the entire growth process, use reflection high-energy electron diffraction (RHEED) technology to monitor the growth of the material in real time to ensure that Si atoms uniformly replace the tetrahedrally coordinated Ga(1) atoms in ε-Ga2O3 and grow a high-quality Si-doped ε-Ga2O3 material thin film.

[0033] Material property testing

[0034] Crystal structure analysis: Use an X-ray diffractometer (XRD) to analyze the crystal structure of the prepared material. Place the sample on the sample stage of the XRD instrument and scan it within a specific angular range and scanning speed. The test results show that the diffraction peaks of the sample highly match the standard diffraction peaks of ε-Ga2O3, indicating that the material has good crystallinity and the doping of Si does not change its crystal structure type. By using the peak position shift of the XRD pattern and applying relevant formulas to calculate the lattice parameters, it is found that the lattice constant is increased compared with that of undoped ε-Ga2O3, which is consistent with the influence of the Coulomb repulsion and ion radius difference between Si and Ga in the theoretical analysis.

[0035] Conductivity testing: The four-probe method is used to measure the conductivity of the material. Place the four probes of the four-probe tester vertically and evenly on the surface of the sample to ensure good contact between the probes and the sample. Apply a certain current through the tester, measure the voltage drop on the sample, and obtain the conductivity according to the calculation formula of the four-probe method. After testing, the conductivity of this sample is 3.2×10- 3 S / cm, which is significantly improved compared with the intrinsic ε-Ga2O3 material.

[0036] Optical property test: Use a spectrometer to measure the absorption spectrum of the material in the deep ultraviolet band. Place the sample in the sample optical path of the spectrometer. The spectrometer emits deep ultraviolet light of different wavelengths through the sample, and the detector measures the intensity of the transmitted light. By analyzing the change of the transmitted light intensity with wavelength, the absorption spectrum is obtained. It can be seen from the spectrum that the optical absorption edges of the material in the x, y, and z directions are 5.848 eV, 5.513 eV, and 5.583 eV respectively, and the average optical absorption edge is 5.646 eV, which is close to the theoretically calculated optical band gap, indicating that the material has good deep ultraviolet light absorption performance.

[0037] Example 2: Preparation of ε-Ga2O3 material with Si doping concentration of 1.25 at%

[0038] Construct a calculation model and optimize parameters: Repeat the steps of constructing a calculation model and optimizing parameters by first-principles calculation in Example 1. Just when constructing the model, construct an ε-Ga2O3 model with a Si doping concentration of 1.25 at%, and set a 3×3×3 Monkhorst-Pack type k-point grid for the 2×1×1 supercell.

[0039] Material preparation (chemical vapor deposition method): Set up the chemical vapor deposition equipment and check the airtightness of the equipment and the working status of each component. After evacuating the reaction chamber, introduce a high-purity carrier gas (such as argon) for purging to remove residual impurities. Place the substrate in a suitable position in the reaction chamber and heat it to 700 °C. According to the accurately calculated ratio, introduce reaction gases containing Ga, O, and Si (such as trimethylgallium, oxygen, and silane) into the reaction chamber. Precisely control the flow rate of the Si-containing compound (silane) in the reaction gas through a mass flow controller, and at the same time strictly control the reaction temperature and reaction time to 60 minutes. During the reaction, use a quartz crystal microbalance to monitor the film growth rate in real time to ensure that Si atoms uniformly replace the Ga(1) atoms in the tetrahedral coordination position in ε-Ga2O3, and finally obtain an ε-Ga2O3 material with a Si doping concentration of 1.25 at%.

[0040] Material property test

[0041] Crystal structure analysis: Also use XRD to detect the crystal structure of the material. The test results show that the diffraction peaks of the material match well with the standard pattern, and the crystallinity is good. The lattice constant further increases, which is consistent with the influence law of the increase in doping concentration.

[0042] Conductivity test: Measure by the four-probe method. The conductivity of this sample is 8.7×10 -3S / cm. The conductivity has increased compared to Example 1, demonstrating that as the Si doping concentration increases, the conductivity of the material improves.

[0043] Optical property test: The absorption spectrum was tested by a spectrometer. The optical absorption edges of the material in the x, y, and z directions are 6.077 eV, 5.777 eV, and 5.972 eV respectively, and the average optical absorption edge is 5.941 eV. The optical bandgap increases, and the deep ultraviolet light absorption performance is further improved.

[0044] Example 3: Preparation of ε-Ga2O3 material with a Si doping concentration of 2.5 at%

[0045] Constructing the calculation model and optimizing parameters: Similar to Examples 1 and 2, a model of ε-Ga2O3 with a Si doping concentration of 2.5 at% was constructed, and a Monkhorst-Pack type k-point mesh of 2×4×4 was set for the 3×1×1 supercell to complete the construction of the calculation model and parameter optimization.

[0046] Material preparation (molecular beam epitaxy method): The ultra-high vacuum equipment was used again, and the substrate was heated to 550 °C. In terms of the evaporation source, the evaporation rate of the Si source was increased, and the evaporation amounts of the Ga and O sources were adjusted accordingly to ensure the coordination of atomic ratios. During the growth process, the growth thickness and optical property changes of the thin film were monitored in real time by an in-situ spectroscopic ellipsometer to ensure that Si atoms were uniformly substituted and the doping concentration reached 2.5 at%, and the ε-Ga2O3 material with this doping concentration was successfully prepared.

[0047] Material property test

[0048] Crystal structure analysis: After XRD testing, the material maintains a good crystal structure, and the lattice constant continues to increase, meeting the theoretical expectations.

[0049] Conductivity test: The conductivity of this sample measured by the four-probe method is 1.5×10 -2 S / cm, which is the highest conductivity among the three examples, indicating that the doping concentration has a significant effect on improving the conductivity.

[0050] Optical property test: The test results of the spectrometer show that the optical absorption edges of the material in the x, y, and z directions are 6.498 eV, 6.289 eV, and 6.422 eV respectively, and the average optical absorption edge is 6.402 eV, which is consistent with the theoretical optical bandgap, and the deep ultraviolet light absorption performance is excellent.

[0051] Through the above specific embodiments and comprehensive performance tests, it can be fully demonstrated that the Si-doped ε-Ga2O3 material prepared by the present invention can exhibit good crystal structures at different doping concentrations. Moreover, with the increase of the Si doping concentration, the conductivity and deep ultraviolet light absorption performance of the material are effectively improved, verifying the feasibility of the preparation method of the present invention and the superiority of the material performance.

[0052] Experimental process:

[0053] Crystal structure analysis (using an X-ray diffractometer, i.e., XRD)

[0054] Sample preparation: Cut the prepared Si-doped ε-Ga2O3 material sample into an appropriate size, generally 1-2 square centimeters, to ensure that the sample surface is flat and smooth. Polish the sample surface with sandpaper to remove possible impurities and uneven layers on the surface, and then ultrasonically clean it successively with deionized water and alcohol to remove surface debris and organic substances. After cleaning, dry the sample for standby.

[0055] Instrument calibration: Before testing, calibrate the XRD instrument. Use a standard sample (such as high-purity silicon powder) to debug parameters such as the angle accuracy and intensity calibration of the instrument to ensure the accuracy of the instrument measurement. Set the tube voltage of the instrument to 40 kV and the tube current to 30 mA to generate a stable X-ray source.

[0056] Testing process: Carefully place the prepared sample on the sample stage of the XRD instrument, and adjust the sample position to make its center coincide with the rotation axis of the instrument. Set the scanning range, usually 20°-80°, the scanning step size to 0.02°, and the scanning speed to 0.5° per second. Start the instrument for scanning. The X-ray irradiates the sample, and the generated diffraction signal is received by the detector and converted into an electrical signal, and then converted into a diffraction pattern through the data processing system.

[0057] Data analysis: After obtaining the diffraction pattern, compare it with the standard diffraction pattern of ε-Ga2O3 (such as JCPDS card data). Determine the crystal structure of the sample by analyzing the position, intensity, and shape of the diffraction peaks. According to Bragg's law (nλ = 2dsinθ, where n is the diffraction order, λ is the X-ray wavelength, d is the interplanar spacing, and θ is the diffraction angle), calculate the change in the lattice constant through the change in the position of the diffraction peak. Use the Scherrer formula ( D is the grain size, K is a constant, and β is the full width at half maximum of the diffraction peak) to calculate the grain size.

[0058] Conductivity test (using the four-probe method)

[0059] Sample Preparation: Cut the prepared Si-doped ε-Ga2O3 material into regular sheets or blocks, ensuring that the sample surface is flat and free of obvious defects. For thin film samples, ensure that they are firmly attached to the substrate. Fix the sample on the test bench using conductive silver paste to ensure good contact between the sample and the test bench.

[0060] Instrument Calibration: Calibrate the four-probe tester using a standard resistor to ensure the accuracy of the instrument measurement. Set the output current of the instrument's current source, generally in the range of 1 - 10 mA, to avoid damage to the sample or affecting the measurement results caused by excessive current.

[0061] Testing Process: Place the four probes of the four-probe tester vertically and evenly on the sample surface, and keep the distance between the probes fixed (usually 1 mm). Turn on the current source to allow current to pass through the two outer probes, and measure the voltage drop between the two inner probes. To reduce the contact resistance and measurement error, multiple measurements need to be carried out at different positions, and record the current value I and voltage value V after each measurement.

[0062] Data Analysis: According to the calculation formula of the four-probe method (where σ is the conductivity, ρ is the resistivity, and d is the probe spacing), calculate the conductivity of the sample. Conduct statistical analysis on the data of multiple measurements, and take the average value as the measurement result of the sample's conductivity.

[0063] Optical Property Testing (Measure the deep ultraviolet absorption spectrum using a spectrometer)

[0064] Sample Preparation: Process the Si-doped ε-Ga2O3 material sample into a thin sheet with a uniform thickness, generally between 0.1 - 1 mm. For thin film samples, directly test the substrate with the thin film. Ensure that the sample surface is clean, free of dust and stains, to avoid affecting the transmission and absorption of light.

[0065] Instrument Calibration: Before testing, calibrate the spectrometer. Use a standard light source (such as a deuterium lamp or a tungsten lamp) to debug parameters such as the wavelength accuracy and intensity calibration of the spectrometer to ensure the accuracy of the instrument measurement. Set the scanning range of the spectrometer to the deep ultraviolet band (such as 200 - 400 nm), and the scanning step size to 1 nm.

[0066] Testing Process: Place the sample in the sample optical path of the spectrometer, ensuring that the sample can completely cover the area through which the light passes. The spectrometer emits deep ultraviolet light of different wavelengths through the sample, and the detector measures the intensity of the transmitted light. During the testing process, it is necessary to keep the ambient light stable to avoid interference from external light on the measurement results. To obtain an accurate absorption spectrum, first measure the background light intensity (i.e., the light intensity I0 without the sample), and then measure the light intensity I after passing through the sample.

[0067] Data Analysis: According to the absorption coefficient formula (where α is the absorption coefficient and d is the sample thickness), calculate the absorption coefficients at different wavelengths. By analyzing the variation curve of the absorption coefficient with wavelength, determine the optical absorption edge of the material. The optical absorption edge is generally defined as the energy value corresponding to the wavelength when the absorption coefficient reaches a certain specific value (such as 10 3 cm -1 ). The optical bandgap of the material can also be calculated from the absorption spectrum. According to the formula αhν = A(hν - E g ), n / 2 (where hν is the photon energy, A is a constant, E g is the optical bandgap, and n takes values according to the type of transition. For direct bandgap semiconductors, n = 1; for indirect bandgap semiconductors, n = 2), the optical bandgap value is obtained by fitting and analyzing the absorption spectrum data.

[0068] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0069] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

[0070] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A Si-doped ε-Ga2O3 material with high electrical conductivity and deep ultraviolet light absorption performance, characterized in that: The doping concentration of Si in the Si-doped ε-Ga2O3 material is 0.83at%-2.5at%, and Si atoms replace tetrahedrally coordinated Ga(1) atoms in ε-Ga2O3.

2. The Si-doped ε-Ga2O3 material with high electrical conductivity and deep ultraviolet light absorption performance according to claim 1, characterized in that: After the material is doped with Si, the Fermi level moves upward into the conduction band, and the Si3s orbital electrons occupy the conduction band bottom (CBM).

3. The Si-doped ε-Ga2O3 material with high electrical conductivity and deep ultraviolet light absorption performance according to claim 1, characterized in that: The optical band gap of the material increases with the increase of Si doping concentration, and the average optical absorption edge gradually becomes larger.

4. The Si-doped ε-Ga2O3 material with high electrical conductivity and deep ultraviolet light absorption performance according to claim 1, characterized in that: The band gap width of the doped material gradually decreases as the Si doping concentration increases.

5. A method for preparing the Si-doped ε-Ga2O3 material with high electrical conductivity and deep ultraviolet light absorption performance as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Constructing a computational model: Determine the initial lattice parameters of ε-Ga2O3 with reference to the experimental values, use the 2×1×1 supercell of ε-Ga2O3, consider four doping structures where Si replaces Ga(1), Ga(2), Ga(3) and Ga(4), calculate the total energy of different doping structures, determine that Si tends to replace Ga(1) atoms to achieve doping, and thus construct ε-Ga2O3 models with different Si doping concentrations; S2. Optimization parameters of first-principles calculations: Using the CASTEP module of the Materialstudio platform, the first-principles plane wave pseudopotential method based on density functional theory (DFT) was used for calculations; periodic boundary conditions were used, and the generalized gradient approximation (GGA) and Perdew-Burke-Ernzerhof (PBE) were used to treat the exchange correlation energy; ultrasoft pseudopotentials were selected to describe the interaction potential between the ion core and the valence electrons, and the valence electron configuration [Ga]3d was set. 10 4s 2 4p 1 、[O]2s 2 2p 4 、[Si]3s 2 3p 2 ; Using the GGA+U method, the parameters of Ud, Ga and Up, O are set to 13.6eV and 8.3eV respectively; the plane wave cutoff energy is determined to be 450eV, and the corresponding Monkhorst-Pack type K-point grids are set for different unit cells. The 1×1×1 supercell uses a 3×2×2 grid, the 2×1×1 supercell uses a 3×3×3 grid, and the 3×1×1 supercell uses a 2×4×4 grid; S3. Material preparation: According to the optimized parameters mentioned above, Si-doped ε-Ga2O3 materials are prepared by molecular beam epitaxy or chemical vapor deposition. During the preparation process, the reaction temperature, gas flow rate and doping source concentration are strictly controlled to ensure that Si atoms uniformly replace the tetrahedral coordinated Ga(1) atoms in ε-Ga2O3, and the doping concentration is controlled in the range of 0.83at%-2.5at%.

6. The method for preparing a Si-doped ε-Ga2O3 material with high electrical conductivity and deep ultraviolet light absorption performance according to claim 5, characterized in that: In the step of constructing the calculation model, the calculation formula used to calculate the total energy is: E f =E T (Si x Ga 1-x O3)-E T (Ga2O3)-μ Si +μ Ga , where E T (Si x Ga 1-x O3) is the total energy of ε-Ga2O3 supercells with different concentrations of Si substitution doping, E T (Ga2O3) is the total energy of intrinsic ε-Ga2O3 of the same supercell, μ Si is the chemical potential of Si atoms added to the supercell, μ Ga is the chemical potential of Ga atoms.

7. The method for preparing a Si-doped ε-Ga2O3 material with high electrical conductivity and deep ultraviolet light absorption performance according to claim 5, characterized in that: In the first principle calculation optimization parameter step, the LBFGS algorithm was used for structural optimization. The atomic coordinates and unit cell volume of the model were fully relaxed before calculation. The self-consistent optimization parameters included: the energy accuracy was set to 5.0×10 -6 eV / atom; the precision of the atomic interaction force is set to The precision of crystal internal stress is set to 0.02GPa; the precision of atomic maximum displacement is set to When the above four parameters reach or exceed the set accuracy, the structural optimization is completed.

8. The method for preparing a Si-doped ε-Ga2O3 material with high electrical conductivity and deep ultraviolet light absorption performance according to claim 5, characterized in that: When using molecular beam epitaxy, it is carried out in an ultra-high vacuum environment. The substrate is heated to a specific temperature, and Ga, O and Si sources are evaporated separately. The target doping concentration is achieved by precisely controlling the evaporation rate of the Si source.

9. The method for preparing a Si-doped ε-Ga2O3 material with high electrical conductivity and deep ultraviolet light absorption performance according to claim 5, characterized in that: When using chemical vapor deposition to prepare, the flow rate of Si-containing compounds in the reaction gas, reaction temperature, reaction time and other parameters are precisely controlled to achieve uniform replacement of Si atoms in the tetrahedral coordinated Ga(1) atom positions in ε-Ga2O3 and control of target doping concentration.

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