Quantitative lifetime measurements with photoluminescence imaging

The measurement of the effective carrier lifetime in silicon has a high importance for the material characterization in the field of photovoltaics since carrier lifetime represents a central quality factor in solar cell production. Photoluminescence has recently evolved as a fast measurement technique for the determination of the minority carrier lifetime in silicon wafers. While PL images of relative values are already available, up to now suitable calibration methods for absolute lifetime values have been developed only for measurements with low spatial resolution. In this paper we propose two different calibration methods for Photoluminescence Imaging measurements with a high spatial resolution: (i) A self consistent calibration procedure is applied to PLI measurements. (ii) We demonstrate a method calibrating relative values of PLI by comparison with a CDI lifetime measurement. The second calibration method accounts for the non-linearity of the PLI signal with lifetime as well as for reabsorption effects.