Capability of photoluminescence for characterization of multi-crystalline silicon

Application of various characterization methods for the investigation of photovoltaic materials allows fast progress in perfection of their quality. However, capabilities of the methods should be clearly understood and the methods should be applied in the correct manner to avoid false and/or unreliable interpretation of the results. We applied photoluminescence (PL) for characterization of multi-crystalline silicon (mc-Si) samples and compared the obtained results with carrier lifetime measurement data for the same samples. The analyses revealed strong influence of surface recombination and optical shadowing from grain boundaries on the interpretation of the PL results. Proper surface passivation allows application of defect-related luminescence for the characterization of mc-Si along with traditionally used band-to-band luminescence.