Comparison of spatially resolved carrier lifetimes in mc-Si with solar cell and material characteristics
We introduce a novel application of modulated free carrier absorption (MFCA) for measuring minority carrier lifetimes in multicrystalline silicon with high spatial resolution. The improved lateral resolution compared to other contactless techniques allows the correlation between these lifetime maps and solar cell characteristics as well as microscopic properties, like dislocations, precipitates, oxygen concentration, etc. Comparisons of the lifetime maps measured on the starting material and light beam induced current (LBIC) maps exhibit a very good qualitative correlation of the structures observed in both cases. In addition, correlations to microscopic characteristics like high dislocation density in regions with low lifetimes are investigated and a comparison with spatially resolved FT-IR measurements of the interstitial oxygen concentration is performed.