It was pointed out that Cu(In,Ga)Se2/CdS/ZnO solar cells required at least 1018/cm2 of 1MeV electrons to degrade their power-conversion efficiency by more than 25%. Even after such irradiation, annealing at 130 to 160C led to a full performance recovery. Isochronal annealing experiments here revealed that annealing of the irradiation-induced defects involved an activation energy of 1.05eV.

Defect Annealing in Cu(In,Ga)Se2 Heterojunction Solar Cells after High-Energy Electron Irradiation. A.Jasenek, H.W.Schock, J.H.Werner, U.Rau: Applied Physics Letters, 2001, 79[18], 2922-4