Microstructural analysis of crystal defects leading to potential-induced degradation (PID) of Si solar cells

A monocrystalline Si solar cell with a low corrugation front side texture was processed to a mini module and has been stressed under potential-induced degradation (PID) conditions. Subsequently, a sample delaminated from PID- affected area has been prepared and investigated down to the microscale employing SEM/EBIC, ToF-SIMS depth profiles and TEM at defect structures. The electrical shunts resulting from PID are confirmed to be locally distinct and coincide with Na aggregations in the antireflective coating (ARC). Moreover, by means of EBIC and TEM measurements these shunts are found to be spatially associated to structural defects within the silicon crystal.