Simultaneous stress and defect luminescence study on silicon

Internal stress is strongly correlated with the mechanical stability of silicon wafers and with the distribution of defects and thus the minority carrier lifetime, which is often the limiting parameter for multicrystalline (me) silicon solar cells. Therefore, internal stress is a highly relevant parameter for me silicon. In this paper, a qualitative internal stress measurement technique by photoluminescence spectroscopy for me silicon is presented. This technique is based on the stress-induced-bandgap energy shift. Stress measurements are compared to defect luminescence images, which are gathered in the same measurement. The method is evaluated by stress measurements with micro-Raman spectroscopy.