Radiation testing of Si PERC and diffused-junction GaAs solar cells for space applications

We report the performance of Si PERC and diffused-junction GaAs solar cells following irradiation by 1 MeV electrons at a fluence range of ~2 × 10¹⁴ to 2 × 10¹⁵ cm⁻². The study supports our analysis of flight results obtained in 2023, in which research samples of these and other types of low-cost solar cells were characterized during an ~11-month mission in low-earth orbit (LEO). Cells that were flown with little or no radiation shielding were damaged by radiation in the space environment. We present the results of our radiation testing to better correlate the observed degradation with that predicted by commonly available modelling tools, and to assist others in designing appropriate shielding for such cells in future space missions.