Radiation hardness and post irradiation regeneration behavior of GaInAsP solar cells

Recent developments have renewed the demand for solar cells with increased tolerance to radiation damage. To investigate the specific irradiation damage of 1 MeV electron irradiation in GaInAsP lattice matched to InP for varying In and P contents, a simulation based analysis is employed: by fitting the quantum efficiency and open-circuit voltage simultaneously before and after irradiation, the induced changes in lifetime are detected. Furthermore, the reduction of irradiation damage during regeneration under typical satellite operating conditions for GEO missions (60 degrees C and AMO illumination) is investigated. A clear decrease of the radiation damage is observed after post irradiation regeneration. This regeneration effect is stronger for increasing InP-fraction. It is demonstrated that the irradiation induced defect recombination coefficient for irradiation with 1 MeV electrons after regeneration for 216 h can be described with a linear function of InP-fraction between 1.10(-5) cm(2)/s for GaAs and 7.10(-7) cm(2)/s for InP. The results show that GaInAsP is a promising material for radiation hard space solar cells.