Behavior of Solar Cells Under 1 MeV Electrons Irradiation: Impact of Diffusion Length Reduction, Majority Carrier Removal and SCR Widening

Abstract

When solar cells are used for space applications, there are exposed to different types of energetic particles such as protons and electrons. Those energetic particles create defects in the base of the solar cell and lead to the degradation of the performances of the solar cell. Three mainly phenomenon observed in silicon solar cells exposed to 1 MeV electron irradiation are decrease in diffusion length, removal of majority charge careers and enlargement of Space Charge Region (SCR). These three phenomenon lead to the type conversion of the base of solar cell and an anomalous behavior of the short-circuit current for a certain value of the fluences. In the present study, theoretical approach is used to investigate the impact of decrease in diffusion length, removal of majority charge careers and enlargement of SCR on the anomalous behavior of the short-circuit current and type conversion of the base. The electric parameters are studied under AM 1.5 for different fluences of 1 MeV electrons. It was found that, defects responsible for the anomalous behavior of the short-circuit current could appear for different values of the fluences and that, the type conversion of the base is caused by the removal of the majority charged carriers and decrease in diffusion length while the anomaly observed in the evolution of the short-circuit current is caused by the widening of the SCR.