Irradiation of thin films and solar cells with 1.00 MeV protons has been investigated for a fluence of 5.0E14 cm−2. We have used photothermal deflection spectroscopy and light conductivity to characterize the effect of irradiation on thin films; current-voltage and quantum efficiency measurements have been used to determine the effects of irradiation on solar cells.
Irradiation introduces increases in the sub-band-gap optical absorption and decreases in the photoconductivity of thin films. The major effect on solar cells is to reduce the short-circuit current. The spectral dependence of the quantum efficiency is reduced in a somewhat uniform manner with irradiation and also recovers in a uniform manner with annealing. Investigations of the annealing behavior of both thin films and solar cells show similar behaviors in the measured properties. The properties of both the films and cells are essentially restored with a one-hour anneal at 200 °C. Attempts have been made to use simple models to calculate defect densities and carrier transport.