Trapping of minority carriers in multicrystalline silicon

Photoconductance measurements have shown anomalously high effective carrier lifetimes on cast multicrystalline silicon wafers. This anomaly is demonstrated as the result of minority carrier trapping, and is explained both quantitatively and qualitatively using a simple model based on trapping centers. Fitted to quasi-steady-state photoconductance data, the model reveals the trap density, trap energy and the mean-trapping time to mean-escape time ratio. Trap density correlates to dislocation density in the material.