Degradation Behavior of Flexible a-Si/a-SiGe/a-SiGe Triple-Junction Solar Cells Irradiated With Protons

Electrical performance degradation of a-Si/a-SiGe/a-SiGe triple-junction solar cells due to irradiation of protons with different energies and their performance recovery at room temperature (RT) just after irradiation are reported. The current-voltage characteristics are measured in situ, and the results show that all the parameters recover with time after proton irradiation is stopped. The degradation is scaled by a unit of displacement damage dose independent of proton energy, indicating that the proton-induced degradation is mainly caused by the displacement damage effects. By analyzing the quantum efficiency variations due to irradiation, it is clarified that the top subcell recovers more markedly at RT than the other subcells, and the recovery of the middle cell is less pronounced.