Injection Dependent Lifetime Spectroscopy for Two-Level Defects in Silicon

Injection dependent lifetime spectroscopy is widely used in the silicon photovoltaic research community for defect parameterization and defect identification. In most cases, the measured injection dependent lifetime cannot be modeled by the presence of a single level defect. It is often assumed that two independent single-level defects are coexisting in the sample. The possibility of a single defect with two energy levels is seldom considered. In this work, we first investigate the possible error when a two-level defect is analyzed as two single-level defects, highlighting the importance of considering the possibility of a two-level defect. We then propose a procedure for fitting the measured injection dependent lifetime using a two-level defect recombination statistic.