Ionization effects on Cu(In, Ga)Se₂ thin-film solar cells

Cu (In, Ga) Se₂ (CIGS) solar cells were irradiated with 60, 100, and 250 keV electrons to reveal the characteristics of radiation induced defects. Electrons with less than 200 keV energy cannot generate any displacement defects in CIGS materials. In addition, a low amount of the electrons can improve the roll-over behavior in current-voltage characteristics of CIGS solar cells. However, the deterioration of the electrical performance in CIGS solar cells irradiated with a high amount of electrons was observed. The deterioration rate on the cells irradiated with lower-energy electrons was higher than that induced by electrons with higher-energy. The degradation curve of J_SC based on the ionizing dose estimated from the ionizing energy loss model does not depend on the energy of electrons. Therefore, it implies that the electrons can degrade CIGS solar cells due to the ionization effect. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)