Simulation Analysis And Electron Irradiation Effect Research Of High Efficiency Multi-junction GaAs Solar Cell

In order to ensure the long-term and stable operation of the spacecraft,GaAs-based multi-junction solar cell with high efficiency,stability,and radiation resistance have become hot research topics in space solar cells.Therefore,in this theis,the theoretical design and fitting verification of the IMM4J solar cell and its key sub-cells were carried out and the effect of electron irradiation and damage mechanism were also studied.At the same time,the theoretical design and comparative analysis of the Bragg reflector suitable for the UMM3J solar cell were carried out,and the research on the effect of electron irradiation was conducted to verify the anti-irradiation feasibility of the Bragg reflector.The main conclusions were as follows:By using APSYS semiconductor device simulation software,the structure parameters of the IMM4J solar cell and its key sub-cells were designed and opimized,The results show that,the the theoretically designed IMM4J solar cell V_oc was 3.49V,J_sc was 16.24mA/cm²,and the In_0.3Ga_0.7As sub-cell current was consistent with the IMM4J solar cell.At the same time,with the increase of irradiation fluence,the internal defects growth rate of In_0.3Ga_0.7As was becoming larger than those of In_0.58Ga_0.42As.Before irradiation,the simulation errors of the V_oc and J_sc of IMM4J were 1.2%and 0.17%,respectively.The defect inside the IMM4J solar cell was related to the capture cross section and the trap concentration of In_0.3Ga_0.7As sub-cell,revealing that the In_0.3Ga_0.7As sub-cell was the current-limiting junction.By performing 1MeV high-energy electron irradiation experiments on the IMM4J solar cell and its key sub-cells.The results show that,with the increase of the irradiation fluence,the electrical performance of solar cells degradation becomes more serious,and the degradation of the spectral response curve in the long-wavelength direction was more serious,revealing that the electron irradiation has a greater damage to the base region of solar cells.The V_oc and I_sc of the IMM4J solar cell simulation and experimental errors were 6.16%and 1.53%,among which the electrical parameters V_oc,I_sc,and P_max degrading linearly with the electron fluence log_?,and the degradation rate C_p in I_sc was larger than V_oc.From a process point of view,the buffer layer and tunnel junction preparation process affect the electrical performance of IMM4J solar cell.The use of superlattice structure can improve the electrical performance,and the tunnel junction with low doping concentration has an impact onthe ability of anti-radiation.By using Macleod optical film software,the theoretical design and comparative analysis of the Bragg reflector structure suitable for UMM3J cells were carried out,and performed 1MeV electron irradiation experiments on the solar cell.The results show that,the simulated and experimental Bragg reflector has a center wavelength error of 0.44%and a maximum reflectance error of 0.3%.With the increase of the irradiation fluence,the electrical performance degradation more severely,and V_oc,I_sc,P_max in UMM3J solar cell degrading linearly with the electron fluence log_?,and the degradation rate C_p in I_sc was larger than V_oc.The more serious of the spectral response curve degradation in long-wave direction,the degradation rate C_p in I_sc of the Ge were larger than those of other sub-cells,and the current of the GaInP sub-cell is consistent with that of the UMM3J solar cell.In the Bragg reflector structure region,the center wavelength of the Bragg reflector region does not change significantly at910 nm,and the reflectance in maximum reflectance slightly degradaded.The Bragg reflector was still able to respond to and increase the I_sc when the fluence was below2×10¹⁵e/cm²,revealing that the Bragg reflector has a certain positive effect on anti-irradiation.