Displacement damage analysis of single-junction and triple-junction GaAs solar cells induced by electron irradiation

Space-graded single-junction (SJ) and triple-junction (TJ) GaAs solar cells, produced by MOCVD, are evaluated through electron-irradiation at the energy of 1MeV, 1.5MeV and 2MeV to compare radiation effects of electrons on these solar cells, and also to provide experimental data for predictions of the cell performances in space. Mean degradations of the short circuit current, open circuit voltage and maximum power are presented and analyzed. Compared to the radiation data of the single-junction GaAs cell, the triple-junction GaAs cell has a superior radiation-hardness performance at the same electron energy and fluence. Degradations at different electron energies have been correlated with displacement damage dose. A good linearity are obtained between the effective electron displacement damage dose and the degradation parameters. The performance prediction of both solar cells in space can be readily predicted by the approach.