Influence of different transition metal contaminations on degradation and regeneration in mc-Si

Light and elevated temperature induced degradation (LeTID) affects significantly the performance of multicrystalline Silicon (mc-Si) solar cells. The underlying mechanisms of LeTID and following regeneration are still unknown and might depend on contaminations. To investigate the influence of different transition metals on the degradation and regeneration behavior, mc-Si ingots were intentionally contaminated in the Si melt with either 20 ppma Fe, Cu, Cr or a combination of Fe and Cu. Minority charge carrier lifetime (eff) samples were processed and the degradation and regeneration behavior under illumination (0.9 ± 0.1 sun) and elevated temperature (75°C) is measured repetitively by time-resolved photoluminescence imaging (TR-PLI) at room temperature. The resulting minority charge carrier lifetime maps are analyzed and the effective defect concentration within one sample and also for differently contaminated samples were calculated. This approach leads to different defect generation rates for the differently contaminated samples, which might hint to an influence of different transition metals on the LeTID causing defect.publishe