Method and system for constructing proton and electron comprehensive irradiation damage model of GaAs triple-junction battery

Abstract

The invention relates to a method and a system for constructing a proton and electron comprehensive irradiation damage model of a GaAs triple-junction battery. According to the model, data are obtained through rigorous single and comprehensive irradiation tests, and the model is repeatedly verified and iteratively optimized on the basis of the data until the model with relatively high precision is obtained. And the accurate model is utilized to predict damage conditions under other irradiation fluence conditions, so that the damage model of the GaAs triple-junction cell under proton and electron comprehensive irradiation is accurately constructed. Through simulation analysis of the electrical properties and internal parameters of the battery, the irradiation damage condition borne by the battery in the operation process of the full-electric push rail can be more accurately grasped, and a solid theoretical basis is provided for deep research of comprehensive irradiation damage rules and mechanism research. In addition, the comprehensive irradiation simulation model can predict the performance degradation trend of the battery on the full-electric propulsion track, the time of a ground evaluation test is shortened, and the economic cost of a ground simulation test can be greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, specifically to a method and system for constructing a comprehensive irradiation damage model for GaAs triple-junction solar cells. Background Technology

[0002] All-electric propulsion satellites, with their significant advantages such as high specific impulse, low launch weight, long lifespan, and high control precision, have become an important trend in the development of aerospace technology. Among numerous solar cells, GaInP / GaAs / Ge triple-junction solar cells stand out. They possess many advantages, including structural stability, high reliability, small size and light weight, and high photoelectric conversion efficiency, and are therefore widely used in space power systems.

[0003] From both domestic and international research perspectives, researchers have conducted in-depth experimental studies on the combined proton and electron irradiation damage of solar cells such as Si and InGaAs. However, for GaAs triple-junction solar cells, only experimental and simulation studies on proton and electron single-irradiation damage have been carried out. Regrettably, research on the combined high-energy proton and electron irradiation damage of GaAs triple-junction solar cells in the orbital environment of all-electric propulsion satellites remains a blank.

[0004] Current research has explored simulation models of proton and electron irradiation in batteries, but these models have limitations, only providing electrical parameters of the battery under a single irradiation source. Furthermore, existing research has largely neglected the crucial area of ​​the spatial distribution characteristics of internal physical parameters within the battery.

[0005] Furthermore, when the battery is used in all-electric propulsion orbital motion, it will inevitably traverse the Earth's internal and external radiation belts repeatedly. During this process, the battery will be subjected to alternating proton and electron radiation multiple times. Since ground-based simulation experiments face significant difficulties in conducting the same number of alternating radiation events, modeling and simulation analysis are urgently needed to more accurately understand the battery's performance under such complex conditions. Summary of the Invention

[0006] To effectively address the performance degradation of GaAs triple-junction solar cells under high-energy proton and electron combined irradiation in an all-electric propulsion orbit environment, this invention proposes a method and system for constructing a proton and electron combined irradiation damage model for GaAs triple-junction solar cells. Through simulation, the distribution of various parameters inside the cell is accurately calculated, and combined with experimental results, the method for evaluating radiation damage of solar cells in all-electric propulsion application scenarios is analyzed and improved, providing theoretical support for its space application.

[0007] To achieve the above objectives, the technical solution of this invention is as follows: A method for constructing a proton and electron combined irradiation damage model for GaAs triple-junction solar cells includes the following steps: S1. Construct a simulation structural model of the GaAs triple-junction battery using TCAD; S2. Combining the physical model and the simulation structure model, a simulation model of the electrical characteristics of the GaAs triple-junction battery is constructed using the NEWTON iterative method; S3. Compare the electrical parameters obtained in step S1 with the electrical characteristic curves obtained in step S2, calibrate and optimize the battery electrical parameters, and construct an electrical simulation model of the GaAs triple junction battery without irradiation. S4. Using a single irradiation, by adjusting the defect information to match the experimental degradation data, a single irradiation simulation model of GaAs triple junction solar cell under different irradiation conditions is obtained. S5. Defects of different irradiation types are superimposed in irradiation order, and the composite defect parameters are verified and optimized through experimental data to obtain a comprehensive irradiation damage model for GaAs triple-junction solar cells.

[0008] The steps also include: S6. Analyzing the specific distribution of internal parameters of GaAs triple-junction cells based on the comprehensive irradiation damage model; S7. Combining the experimental results with the simulation results obtained from the comprehensive irradiation damage model, conduct research on the laws and mechanisms of irradiation damage.

[0009] Specifically, in step S1, the two-dimensional model of the GaAs triple junction cell includes the thickness of the cell layers, the doping concentration, and the doping method. The bottom electrode of the cell is the cathode, and the top electrode of the cell is the anode.

[0010] Specifically, the fourth, fifth, ninth, and tenth layers of the battery are all tunneling layers with a doping concentration of 10. 19 cm -3 The doping concentration of the remaining layers is on the order of magnitude of 10. 18 cm -3 Magnitude.

[0011] Specifically, the physical models in step S2 include the SRH recombination model, the Poisson equation, the continuity equation, the Auger recombination model, the Fermi-Dirac carrier statistical model, the Conmob concentration-dependent mobility model, the Optr optical recombination model, and the Bgn carrier statistical model. The numerical calculation method includes the NEWTON iterative method.

[0012] Specifically, the calibration optimization in step S3 includes changing the material composition, thickness, and doping concentration of the battery to change the electrical parameters, so that the electrical parameters match the electrical characteristic curve results with a deviation of less than 1%.

[0013] Specifically, the defect information in step S4 includes: defect type, defect energy level, defect concentration, defect capture cross section, and defect degradation factor.

[0014] Specifically, the method for adjusting defect information includes: If the experimental degradation data and defect information correspond to the same defect type or defect energy level, then the defect concentration is changed. If the types or energy levels of defects in the experimental degradation data and defect information are different, then the defect concentration and defect capture cross section are changed.

[0015] Furthermore, the present invention also proposes an electronic system comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the steps of the method described in the present invention.

[0016] Finally, the present invention provides a computer-readable storage medium storing computer instructions for causing the computer to perform the steps of the method described in the present invention.

[0017] The beneficial effects of this invention are: This invention proposes a comprehensive irradiation damage model for GaAs triple-junction solar cells. Through matching and optimization with experimental results, the model exhibits high accuracy. Simulation analysis of its electrical properties and internal parameters allows for a more accurate determination of the irradiation damage suffered by GaAs triple-junction solar cells in an all-electric propulsion orbit, providing theoretical support for elucidating the comprehensive irradiation damage patterns and mechanisms. Furthermore, the comprehensive irradiation simulation model can predict the irradiation degradation trend of the cells in an all-electric propulsion orbit, reducing the time required for ground evaluation tests and significantly lowering the economic cost of ground simulation experiments. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation of the present invention. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the process of the present invention; Figure 2 This is a schematic diagram of the GaAs triple-junction battery structure of the present invention; Figure 3 This is a modeling diagram of the GaAs triple-junction battery of the present invention; Figure 4 This is a comparison of the IV curve experimental and simulation results for the GaAs triple-junction battery of this invention. Figure 5 This is a diagram showing the internal electric field distribution of the GaAs triple-junction battery of the present invention. Figure 6 This is a diagram showing the carrier concentration distribution inside the GaAs triple-junction cell of the present invention. Figure 7 The IV characteristic curves of the GaAs triple-junction battery under different irradiation conditions of the present invention are shown. Figure 8 This invention relates to the hole concentration distribution inside a GaAs triple-junction battery. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1: As Figure 1 As shown, this invention proposes a simulation model for alternating irradiation of a GaAs triple-junction solar cell, comprising the following steps: S1. Constructing a simulation structure model of the GaAs triple-junction solar cell; Based on the battery structure, a two-dimensional TCAD (Technology Computer Aided Design) model is constructed, defining the thickness, doping concentration, doping type, and tunnel junction location of each layer, and adding material parameters for each layer. Material parameters not available in the TCAD software are defined to construct a two-dimensional structural model of a triple-junction GaAs battery.

[0022] Specifically, according to Figure 2 The structure diagram of the GaAs triple-junction solar cell is shown. A two-dimensional model of the cell is constructed using TCAD. The fourth, fifth, ninth, and tenth layers are the tunneling layers of the cell. These band-to-band tunnels are defined, and the doping concentration of the tunneling layers is 10. 19 cm -3 The doping concentration of the remaining layers is on the order of magnitude of 10. 18 cm -3 The order of magnitude is similar, with each layer uniformly doped. A simulation model of the GaAs triple-junction cell is obtained by setting the top electrode as the cathode and the bottom electrode as the anode.

[0023] S2. Construct a simulation model of the battery's electrical characteristics. like Figure 3As shown, the physical models required for the battery are added, and a bias voltage is applied to the battery anode. The electrical characteristic curves of the battery are obtained through numerical calculations. The physical models include the Shockley-Read-Hall (SRH) recombination model, the Poisson equation, the continuity equation, the Standard Auger Model (Auger) recombination model, the Fermi-Dirac carrier statistical model, the Conmob concentration-dependent mobility model, the Optical Recombination Model (Optr), the Bandgap Narrowing (Bgn) carrier statistical model, and the Band-to-band Tunneling (Bbt) model. The NEWTON iterative method is used for numerical calculations.

[0024] To calculate the relevant parameters of a triple-junction solar cell, the theoretical calculations involve the Poisson equation and the carrier continuity equation, as shown below: (1) (2) (3) (4) (5) Equation (1) is the Poisson equation, where ψ is the electrostatic potential, ε is the local dielectric constant, and ρ is the local space charge density. Equations (2) and (3) are carrier continuity equations, where R... p and R n J represents the recombination rate of holes and electrons, respectively. p and J n μ is the current density of holes and electrons, and q is the elementary charge. Equations (4) and (5) are the drift-diffusion transport equations, where μ p and μ n These are the mobilities of holes and electrons, E, respectively. p and E n It is a quasi-Fermi level.

[0025] By calculating the Poisson equation and the continuity equations for electrons and holes, the relevant parameters of a triple-junction solar cell can be solved. In the non-equilibrium state, the continuity equations for electrons and holes are: (6) (7) Where, τ n and τ p D represents the average lifetime of minority carriers (electrons) in the p-region and the average lifetime of minority carriers (holes) in the n-region, respectively.n and D p G is the diffusion coefficient of electrons and holes. n (x) and G p (x) is the generation rate of electrons and holes.

[0026] To simulate nonradiative recombination in the semiconductor bandgap caused by irradiation, the Shockley-Reed-Hall (SRH) recombination model is used, and its expression is as follows: (8) (9) (10) Among them, R SRH It is the SRH recombination rate, R A and R D , where are the recombination rates of acceptor defects and donor defects, respectively, and m and n are the number of acceptor defects and donor defects, respectively. i Where is the intrinsic carrier concentration, k is the Boltzmann constant, T is the absolute temperature (K), g is the degradation factor, and E is the intrinsic carrier concentration. i and E t These are the Fermi level and defect level of intrinsic charge carriers, respectively.

[0027] S3. Electrical simulation model of GaAs triple-junction cell without irradiation The electrical parameters obtained from the TCAD simulation in step S1 are compared with the electrical characteristic curves obtained from the experiment in step S2. By changing the battery's material composition using `x.comp` and `y.comp`, or by changing the thickness of each material layer using the `bot thick` statement and the material doping concentration using the `doping conc` statement, the battery's electrical parameters (such as open-circuit voltage and short-circuit current) can be altered. This further optimizes the model structure, obtaining battery electrical parameters that match the experimental results, with a deviation of less than 1%. The electrical parameters include typical electrical parameters such as the battery's open-circuit voltage and short-circuit current. Figure 4 As shown, an electrical simulation model of a GaAs triple-junction cell without irradiation is obtained.

[0028] S4. Construct a single-irradiation simulation model of GaAs triple-junction solar cells under different irradiation conditions. Irradiation damage simulation was performed on the battery model. To construct the defect model, energy level defects were introduced into the corresponding material for material defect simulation. Information such as the material's energy levels, density, and trapping cross-section were defined to alter the battery's electrical performance and internal parameters. Referring to experimentally obtained electrical parameters, the defect concentration and other defect information in the material were changed to obtain values ​​that matched the experiments, thus deriving the battery's irradiation damage model.

[0029] The lifetimes of electrons and holes are related to the carrier trapping cross-section by the following equation, as shown below: (11) (12) TAUN and These represent electron lifetime and hole lifetime, respectively; SIGN and SIGP represent electron trapping cross-section and hole trapping cross-section, respectively. and These are the electron thermal velocity and the hole thermal velocity, respectively. Let be the defect concentration. As can be seen from the above equation, increasing the defect concentration and carrier capture cross section will lead to a decrease in carrier lifetime, making it more difficult for carriers to be collected by the electrode, thus causing a decline in battery electrical performance. In addition, as can be seen from equations (9) and (10), the closer the defect energy level is to the Fermi level, the higher the SRH recombination rate, the more recombinated carriers, and the more difficult it is for carriers to be collected by the electrode, which will also lead to a decline in battery electrical performance.

[0030] Specifically, based on the electrical simulation model obtained in step S3, a battery irradiation simulation model is constructed using TCAD. First, a relatively simple single-electron (or proton) irradiation simulation model is constructed: Since batteries generate various defect types during irradiation, the most severe defect types of each layer of battery material after irradiation are identified through literature review. Defect information such as material defect types, defect energy levels, and defect trapping cross-sections is added to simulate irradiation damage to the battery. Based on the degradation amplitude of the battery under various irradiation conditions, the defect information is changed to obtain electron (or proton) irradiation simulation models under different irradiation conditions that closely match experimental results. The steps for determining and adjusting the defect information are as follows: 1) Determine whether the most serious defect in each material is a donor defect or an acceptor defect. This step, based on research, shows that the most serious defect in GaInP material is a donor defect, while the most serious defect in GaAs material is an acceptor defect. 2) Determine the energy level positions of the defects, where the energy level positions of defects in GaInP material are approximately 0.55 eV, and the energy level positions of defects in GaAs material are approximately 0.96 eV; 3) The concentration of the defect was determined to be on the order of approximately 10. 14 cm -3 Magnitude; 4) The magnitude of the defect's capture section is determined to be approximately 10. -12 cm 2 Magnitude; 5) The degradation factor of the defect is determined to be approximately 2; 6) Adjust the defect concentration and the capture cross-section value based on the irradiation experiment results. The adjustment method is as follows: If the defect type in the experimental degradation data is the same as the defect type in the defect information, and the defect energy level in the experimental degradation data is the same as the defect energy level in the defect information, then only the defect concentration needs to be changed. If the defect type in the experimental degradation data is different from the defect type in the defect information and / or the defect energy level in the experimental degradation data is different from the defect energy level in the defect information, then change the defect concentration and the defect capture cross section.

[0031] The above process can be used to obtain a single irradiation simulation model of the battery under different irradiation conditions.

[0032] S5. Construct a comprehensive irradiation damage model for GaAs triple-junction solar cells.

[0033] Next, the defect information obtained from single irradiation is substituted into the comprehensive irradiation simulation. The model is verified and iteratively optimized using single and comprehensive irradiation test data. After obtaining a more accurate model, damage prediction is performed under other irradiation flux conditions to obtain an accurate comprehensive irradiation damage model for GaAs triple junction cells.

[0034] For example, in the simulation of combined electron-proton irradiation, the defect information from electron irradiation is first incorporated into the model, followed by the defect information from proton irradiation. Parameters such as defect concentration and trapping cross-section in the proton irradiation defect information are modified. A higher defect concentration results in lower open-circuit voltage and short-circuit current. Specifically, modifying the defect concentration of the top and bottom cells significantly affects the Voc (Open Circuit Voltage) of a triple-junction cell; changing the defect concentration of the middle cell significantly affects the Isc (Short-Circuit Current) of a triple-junction cell; and a smaller trapping cross-section has a greater impact on the electrical performance of the triple-junction cell due to changes in defect concentration. By modifying the parameters, the electrical parameters obtained from the combined electron-proton irradiation simulation are made consistent with those obtained from experimental testing, thus obtaining the combined electron-proton irradiation damage model. The construction of combined irradiation damage models for other different irradiation sequences is similar. The calibration model was validated through several typical integrated irradiation experiments. The input parameters for defect information, such as defect concentration and capture cross-section, were calibrated and optimized to obtain an accurate integrated irradiation defect model. This model was then used to model and simulate the performance damage of solar cells under different doses / fluxes of protons and electrons. This integrated radiation damage model is applicable to a wide energy spectrum, specifically protons: 10 keV–100 GeV; electrons: 1 keV–100 MeV. By inputting particle data under different energy parameters, the corresponding quantitative assessment results of energy deposition damage can be accurately calculated and output.

[0035] The comprehensive irradiation damage model yields the specific distribution of internal parameters in GaAs triple-junction cells. For example, the electric field intensity distribution shows that the electric field intensity in the tunnel junction of a GaAs triple-junction cell is 16 times that of the electric field intensity in the junction regions of each sub-cell. Figure 5 As shown. The carrier concentration distribution indicates that the electron concentration in the emitter region is around 10. 18 cm -3 The electron concentration in the base region is on the order of magnitude of 10. 10 cm -3 The magnitude is such that the hole concentration in the base region is in the range of 10. 17 cm -3 Magnitude, such as Figure 6 As shown.

[0036] By combining experimental and simulation results, we can determine, at the macroscopic level (IV characteristic curve), which irradiation conditions cause more severe battery damage. Furthermore, at the microscopic level, we can use simulated damage models to obtain changes in various parameters within the battery after irradiation. Combined with macroscopic conclusions, we can then study the patterns and mechanisms of irradiation damage.

[0037] like Figure 7 As shown, the V characteristic curve of proton irradiation shows the smallest decrease. oc (Open Circuit Voltage) dropped to 2.439V, I sc (Short-Circuit Curent) drops to 231 mA, followed by electron irradiation, V oc (Open Circuit Voltage) dropped to 2.328V, I sc (Short-Circuit Curent) drops to 218 mA. Under combined irradiation, the battery's electrical parameters decrease the fastest, with its VA... oc (Open Circuit Voltage) drops to 2.3V, I sc (Short-Circuit Curent) dropped to 215mA.

[0038] like Figure 8 As shown, the hole concentration inside the battery decreased to 1.25 × 10⁻⁶ under combined irradiation. 10 cm -3 Significantly lower than 7 × 10⁻⁶ for proton irradiation 10 cm -3 With electron irradiation of 3×10 10 cm -3This indicates that combined irradiation introduces more deep-level defects, causing charge carriers inside the battery to be trapped before reaching the space charge region. This results in a reduced carrier diffusion length, leading to a greater decrease in short-circuit current and open-circuit voltage under combined irradiation, approximately 92% and 86.5%, respectively. The simulation results are consistent with... Figure 7 The experimental results matched, demonstrating the reliability of the irradiation damage model.

[0039] Example 2: This example proposes an electronic system, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the steps of the method described in this invention.

[0040] Example 3: This example proposes a computer-readable storage medium storing computer instructions, which are used to cause the computer to perform the steps of the method described in this invention.

[0041] It should be noted that the processing flows of Embodiments 2 and 3 correspond to the specific steps of the method provided in the embodiments of the present invention, and have the corresponding functional modules and beneficial effects of the method. Technical details not described in detail in this embodiment can be found in the method provided in the embodiments of the present invention.

[0042] This application focuses on the radiation damage effects on space solar cells. Given that protons and electrons account for over 90% of the flux in the space radiation environment, and that the damage dose they induce plays a dominant role in the performance degradation of solar cells, this application primarily constructs a damage model for protons and electrons. It should be noted that although the flux of other high-energy particles such as alpha particles and heavy ions accounts for only about 5%, and their non-ionization energy loss coefficients are generally lower than those of protons and electrons, this application still retains the scalability of the model: by introducing a particle type parameterization module, the applicability of the model in extreme radiation environments such as deep space exploration is enhanced.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for constructing a proton and electron combined irradiation damage model for GaAs triple-junction solar cells, characterized in that, Includes the following steps: S1. Construct a simulation structural model of the GaAs triple-junction battery using TCAD; S2. Combining the physical model and the simulation structure model, a simulation model of the electrical characteristics of the GaAs triple-junction battery is constructed using the NEWTON iterative method. S3. Compare the electrical parameters obtained in step S1 with the electrical characteristic curves obtained in step S2, calibrate and optimize the battery electrical parameters, and construct an electrical simulation model of the GaAs triple junction battery without irradiation. S4. Using a single irradiation, by adjusting the defect information to match the experimental degradation data, a single irradiation simulation model of GaAs triple junction solar cell under different irradiation conditions is obtained. S5. Defects of different irradiation types are superimposed in irradiation order, and the composite defect parameters are verified and optimized through experimental data to obtain a comprehensive irradiation damage model for GaAs triple-junction cells.

2. The proton and electron combined irradiation damage model according to claim 1, characterized in that, The steps also include: S6. Analyze the specific distribution of internal parameters of GaAs triple-junction cells based on the comprehensive irradiation damage model. S7. Combining the experimental results with the simulation results derived from the comprehensive irradiation damage model, conduct research on the laws and mechanisms of irradiation damage.

3. The proton and electron combined irradiation damage model according to claim 1, characterized in that, The simulation structure model of the GaAs triple junction cell in step S1 includes the thickness of the cell layers, the doping concentration, the doping method, the bottom electrode of the cell as the cathode, and the top electrode of the cell as the anode.

4. The proton and electron combined irradiation damage model according to claim 3, characterized in that, The fourth, fifth, ninth, and tenth layers of the battery are all tunneling layers with a doping concentration of 10. 19 cm -3 The doping concentration of the remaining layers is on the order of magnitude of 10. 18 cm -3 Magnitude.

5. The proton and electron combined irradiation damage model according to claim 1, characterized in that, The physical models in step S2 include the SRH recombination model, Poisson equation, continuity equation, Auger recombination model, Fermi-Dirac carrier statistical model, Conmob concentration-dependent mobility model, Optr optical recombination model, and Bgn carrier statistical model.

6. The proton and electron combined irradiation damage model according to claim 1, characterized in that, The calibration and optimization in step S3 includes changing the material composition, thickness, and doping concentration of the battery to match the electrical parameters with the electrical characteristic curve results, with a deviation value of less than 1%.

7. The proton and electron combined irradiation damage model according to claim 1, characterized in that, The defect information in step S4 includes: defect type, defect energy level, defect concentration, defect capture cross section, and defect degradation factor.

8. The proton and electron combined irradiation damage model according to claim 7, characterized in that, The method for adjusting defect information includes: If the experimental degradation data and defect information correspond to the same defect type or defect energy level, then the defect concentration is changed. If the types or energy levels of defects in the experimental degradation data and defect information are different, then the defect concentration and defect capture cross section are changed.

9. A computer-readable storage medium storing computer instructions, characterized in that, The computer instructions are used to cause the computer to perform the method according to any one of claims 1-8.

10. An electronic system comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1-8.

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