Ingot solar cells were found to be predominantly influenced by an homogeneous distribution of recombination centers. However, if the dislocation density exceeded a certain limit, the internal quantum efficiency was reduced by recombination at dislocations. This limit varied in different parts of the wafer. Thus, edge-defined film-fed cells exhibited only lifetime reduction by dislocations whereas cells made from ribbon-growth-on-substrate material were dominated by recombination at grain boundaries. Transmission electron microscopy showed that the extended defects were highly decorated with SiO2 and SiC precipitates.

LBIC investigations of lifetime degradation by extended defects in multicrystalline solar silicon M.Rinio, H.J.Möller, M.Werner: Solid State Phenomena, 1998, 63-64, 115-22