Radiation damage effects on double-junction GaInP2/GaAs solar cells

The radiation effects on a double-junction GaInP2/GaAs solar cell were studied under exposures of 100 keV protons, 10 MeV protons and 1 MeV electrons, in terms of changes on electrical properties and spectral response. The results indicate that the electrical property degradation of the double-junction GaInP2/GaAs solar cell under irradiation occurs mainly due to the damage in the GaAs sub-cell. The GaAs sub-cell damage is primarily attributed to the decrease in collection efficiency of the minority carriers coming from its base bottom. It is revealed from the cell behavior under exposure to 100 keV protons irradiation that under the AM0 illumination, there is no obvious damage defected in the tunnel junction between the GaInP2 and the GaAs sub cells. In addition, the tunnel junction between the GaInP2 and the GaAs sub-cells is stable and no boundary traps are formed.