Electron and proton radiation effects on GaAs and CuInSe2 thin film solar cells

The effects of proton and electron radiation on the performances of GaAs and CuInSe₂/CdZnS (CIS) thin-film solar cells are evaluated. Bare cells (i.e. with no coverglass) were exposed to several energies of electron and proton radiation, and their performances were monitored by illuminated I-V curves, dark I-V curves, and spectral response measurements at different fluence levels. These experiments reconfirm that no measurable damage occurs to CIS solar cells when exposed to 1 and 2 MeV electrons to a total fluence of 5.0*10¹⁵ cm^-2. For proton irradiations, the results indicate that CIS cells are more radiation resistant than GaAs cells, by a factor of ten, when compared at the same energy levels. Comparison of the electron and proton irradiation results to those reported in the literature shows that the thin-film GaAs solar cells are as radiation resistant as other GaAs bulk cells at 1.0 MeV protons and are more radiation resistant at both the 1.0 MeV electron and 200 keV proton energies.