Study of radiation response on single-junction component sub-cells in triple-junction solar cells

The radiation responses of InGaP, (In)GaAs and Ge single-junction sub-cells in a triple-junction space solar cell are studied in order to develop a device simulator which predicts the EOL performance of space solar cells. InGaP top-cells exhibit no significant difference in radiation degradation trends between AM0 light and dark conditions during irradiation. The radiation tolerance of (In)GaAs middle-cells degrades with increasing indium content. However, the absolute value of lsc for a higher In content cell still exceeds that of a GaAs (In=0%) cell after irradiation. Ge bottom-cells exhibit good radiation tolerance as expected. This study is the first to reveal precise radiation response of the sub-cells.