The Effect of Electron Irradiation on Cesium Fluoride‐Free and Cesium Fluoride‐Treated Cu(In1−x,Gax)Se2 Solar Cells

Herein, the effects of electron irradiation on cesium fluoride (CsF)‐free and CsF‐treated Cu(In_1−x,Ga_x)Se₂ (CIGS) solar cells with fluence from 1 × 10¹³ to 1 × 10¹⁷ cm⁻² are investigated. Both CsF‐free and CsF‐treated CIGS solar cells exposed to fluence up to 3 × 10¹⁵ cm⁻² show self‐healing properties, due to the soaking effect from electron bombardment. This feature indicates the robustness of CIGS solar cells for long‐term space explorations. On the other hand, electron irradiation with fluence above 1 × 10¹⁶ cm⁻² suppresses the solar cell performance of both CsF‐free and CsF‐treated samples, which is expected to be due to the formation of irradiation‐induced defects on the CIGS thin film. This result suggests that the formation of irradiation‐induced defects is independent of the incorporation of heavier alkali metals into the CIGS thin films. The defect passivation and/or introduction rates at different fluences are investigated.