In-situ observation of radiation degradation of GaAs solar cells with InGaAs quantum dot layers

Oshima, Takeshi; Nakamura, Tetsuya*; Sugaya, Takeyoshi*; Sumita, Taishi*; Imaizumi, Mitsuru*; Sato, Shinichiro; Matsubara, Koji*; Niki, Shigeru*; Mochizuki, Toru*; Takeda, Akihiro*; Okano, Yoshinobu*

In this study, GaAs PiN solar cells of which i-layer contains or does not contain InAs QD layers are fabricated. The degradation behaviors for the QD solar cells due to proton irradiation are compared to that for the non QD solar cells using an in-situ measurement technique. The maximum power for QD (50 layers) and non-QD GaAs solar cells decreased with increasing fluence of protons with an energy of 150 keV. No significant difference in the degradation behavior between QD and non-QD solar cells is observed. This can be concluded that QD solar cells have an enough potential for space applications because the initial efficiency for QD solar cells is expected to be higher than non-QD solar cells. In addition, annealing of the degraded characteristics of both the QD and the non-QD solar cells was observed under AM0 illumination even at RT.