Radiaton effects on high-efficiency InGaP/InGaAs/Ge triple-junction solar cells developed for terrestrial use

Radiation hardness of terrestrial InGaP/InGaAs/Ge high-efficiency triple-junction solar cells has been studied to clarify the potential of these cells for space use. Comparison of irradiation effects by 1MeV electrons and 3MeV and 10MeV protons on I-V performance parameters of the terrestrial cell and of a space triple-junction cell has exhibited that the radiation tolerance of the terrestrial cell is about one order of magnitude in fluence lower than the space cell, but it is almost equivalent of that of GaAs single junction cells. Results of irradiation tests with various energies of protons (0.03-10MeV) on the terrestrial triple junction cell indicate that a few hundreds keV protons cause the greatest damage to the cell among the energy region. The terrestrial cell is shown to be applicable to gentle environment space missions without any modification.