Electron irradiation test method for the evaluation of space solar cells

Miyamoto, Haruki; Sato, Shinichiro; Oshima, Takeshi; Imaizumi, Mitsuru*; Morioka, Chiharu*; Ito, Hisayoshi; Kawano, Katsuyasu*

InGaP/GaAs/Ge triple-junction (3J) and Si single junction solar cells designed for space application were irradiated with 1.0 MeV- and 0.8 MeV-electrons at 110510/cm in the atmosphere. The distance between the irradiation window and samples was changed from 20 to 50 cm. The accelerated electron energy changed from 1.0 to 0.93 MeV at the surface of samples with 20 cm below the irradiation window. This energy change caused by the energy attenuation of the Ti irradiation window and atmosphere. The electrical properties of solar cells were measured and compared before irradiation to after irradiation. No significant difference in the degradation of 3J solar cells due to electron irradiation was observed in energies range between 0.93 and 0.71 MeV. For Si solar cells, the value of degradation is the same in energies range between 0.93 and 0.87 MeV, however, the decrease in degradation was observed below 0.73 MeV.