Proton radiation analysis of multi junction space solar cells

We report experimental results of proton irradiations with various energies on InGaP/GaAs/Ge triple-junction (3J) solar cells. The 3J solar cells consisting of stacked three different sub-cells (InGaP top cell, GaAs middle cell and Ge bottom cell) were irradiated with various energies of protons. Proton penetration depth was calculated by the TRIM program. Current voltage characteristic under AM0 simulated light and the spectral response under color bias light of the 3J cells were measured before and after the irradiations. Relative damage coefficients were obtained based on the irradiated cell performance. The results have revealed that protons with energy of a few hundred keV cause the most severe damage on 3J cells because the GaAs middle cell has the least radiation tolerance among the three sub-cells. (C) 2003 Elsevier Science B.V. All rights reserved.