Based On Irradiation Damage Modle Of GaAs Solar Cell Researches Carrier Transport Mechanism

The degradation and damage mechanisms caused by irradiation of space charged particles are investigated for the domestic GaAs/Ge solar cells, based on equivalent ground simulation experiments. Nonlinearity of the short-circuit current and the open circuit voltage degradation curves of the solar cells is analyzed by its mathematical model. The change laws of minority carriers’ diffusion length damage coefficient and majority carriers’ removal damage coefficient of space solar cells with the incident electrons energy are established.Electrical performance test results show that the electron fluence is determined, the degradation in electrical characteristics of GaAs/Ge solar cell increases with the increasing of electron energy. After <200 keV proton irradiation GaAs/Ge solar cell, the open-circuit voltage degradation and the maximum power degradation of GaAs/Ge solar cell are largest under 70 keV proton irradiation. The short circuit current degradation is largest when 40 keV proton irradiation. And the short circuit current degradation decreases with increasing of the proton energy. Under the 4 MeV and 10 MeV proton irradiation, the degradation of the electrical characteristics of GaAs/Ge solar cell increases with increasing of the proton energy.Simulation results of the open-circuit voltage degradation model show that under irradiation of the different energy protons, the majority carriers’ removal rate damage coefficient first increases and then decreases with increasing the proton energy reaches a maximum at 100 keV. Under irradiation of the different energy electrons, the majority carriers’ removal rate damage coefficient increases with increasing electron energy. The research results also show that the open-circuit voltage degradation of GaAs/Ge associated with the majority carriers’ removal rate. One of the open-circuit voltage degradable reasons is the carriers’ removal effect in space charged partical irradiation GaAs/Ge solar cell.Simulation results of the short-circuit current degradation model show that under irradiation of the different energy protons, the minority carriers’ diffusion length damage coefficient of GaAs/Ge solar cell decreases with the increase of proton energy. Under irradiation of the different energy electron, the minority carriers’ diffusion length damage coefficient of GaAs/Ge solar cell increases with increasing electron energy. The research results also show that the short circuit current degradation of GaAs/Ge solar cell associated with diffusion length damage coefficient.The equivalent relative damage coefficient results show that the majority carriers’ removal rate damage coefficient of GaAs/Ge solar cell increases first and then decreases with the proton energy increase under the proton radiate, and the change trend of the open-circuit voltage relative damage coefficient of GaAs/Ge solar cell at home and abroad are basically identical. Under the proton irradiation, the minority carriers’ diffusion length damage coefficient of GaAs/Ge solar cell decreases with the proton energy increase, and the change trend of the short-circuit current relative damage coefficient of GaAs/Ge solar cell at home and abroad are basically identical. Under the electron irradiation, the minority carriers’ diffusion length damage coefficient and the majority carrier removal rate damage coefficient of GaAs/Ge solar cell increase with the electron energy increase, and the change trend of the test dates are basically identical.From two aspects of experiments and theoretical analysis, the electrical performance degradation regularity and mechanism of proton and electron irradiation GaAs/Ge solar cell are studied by this paper. The irradiation damage effect is analyzed in solar call from the angle of carriers’ transport mechanism. The results have important significance to reveal the irradiation damage mechanism of the space solar cells.