Investigation of temperature and illumination dependencies of carrier-induced degradation in p-type multi-crystalline silicon

Carrier-induced degradation (CID) in multi-crystalline silicon (mc-Si) solar cells, often also referred to as Light- and elevated Temperature-Induced Degradation (LeTID), significantly affects the performance of mc-Si PERC cells when they are subjected to light or carrier injection. However, the root cause for this degradation has not yet been determined. Previous work has demonstrated that an increase in illumination and temperature can accelerate the defect formation and enable rapid recovery, with variations in degradation and regeneration rates suggesting that competing reactions are likely involved. In this work, we provide further insight into the kinetics of the carrier lifetime evolution of mc-Si wafers using an accelerated high intensity laser technique. The illumination and temperature range investigated is between 14.6 kW/m² to 74.5 kW/m² and 100 °C to 300 °C respectively. The resulting degradation (R_deg) and regeneration (R_reg) rate constants show that both illumination and temperature can substantially alter the reaction rates. For temperatures higher than 250 °C, samples do not show any degradation in lifetime regardless of the illumination intensity applied to the wafer. The activation energies for degradation and regeneration have also been extracted by applying an Arrhenius plot for different illumination intensities.