Published online by Cambridge University Press: 21 February 2011
The efficiency of solar cells fabricated from low-oxygen, high-carbon, EFG silicon ribbon can be improved by pre-annealing the ribbon at 1200°C prior to processing. TEM analysis shows that the increased efficiency is not related to a relaxation of the defect structure. Rather, EBIC investigations demonstrate a continuous reduction of the recombination activity of in-grown crystal defects (dislocations, grain boundaries) with increasing duration of the anneal. Since C is the only element in supersaturation at the annealing temperature, a model is suggested in which metallic contaminants are gettered at small carbon clusters.