Light-induced lifetime degradation in high-performance multicrystalline silicon: Detailed kinetics of the defect activation

We examine the defect activation kinetics in block-cast high-performance multicrystalline silicon (HP mc-Si) under illumination at elevated temperature. Our lifetime analysis shows that the observed light-induced lifetime degradation consists of two separate stages: a fast stage followed by a slow stage. Our experiments reveal that both degradation stages can be fitted using a sum of two exponential decay functions. The resulting degradation rate constants depend both on the temperature and the light intensity applied during degradation. For the fast component, we determine an activation energy of (0.89 ± 0.04)eV from an Arrhenius plot of the degradation rate and for the slow component we determine a value of (0.94 ± 0.06)eV. The activation energies are relatively large, leading to a very pronounced dependence of the degradation rates on temperature. We also observe that both degradation rates show a linear dependence on the applied light intensity during degradation in the examined intensity range between 0.25 and 1.5 suns. •Two-stage degradation in multicrystalline silicon: a slow and a fast one.•Temperature dependence of degradation rates described by an Arrhenius law.•Linear dependence of degradation rates on applied light intensity.•Discussion of a possible defect model to describe our experimental findings.