Recombination activity enhancement by stress in silicon

The recombination activity of grain boundaries and precipitate colonies is analyzed with submicron spatial resolution and compared to the surrounding stress field. This analysis reveals a positive correlation between tensile stress and recombination activity and a negative correlation between compressive stress and recombination activity. This correlation can be explained by the stress induced mobility enhancement due to the strong piezoresistance of silicon. This observation could lead to a significant improvement of multicrystalline silicon solar cells by engineering the incorporated stress fields during the block casting and the solar cell processing.