Implications of grain boundaries on quasi-steady-state photoconductance measurements in multicrystalline and cast-mono silicon

Quasi-steady-state photoconductance is commonly used for measuring the effective lifetime of excess carriers in silicon wafers. A known artifact, unrelated to the sample's lifetime in eddy current based photoconductance measurements, is a strong increase in lifetime at low carrier densities. It is commonly observed in multicrystalline and cast-mono crystalline silicon. This artifact is often attributed to bulk defects changing their charge state and is referred to as trapping.