A critical evaluation of the effective diffusion length determination in crystalline silicon solar cells from an extended spectral analysis

This note draws attention to possible errors when characterizing silicon solar cells by means of the effective minority carrier diffusion length L_b as defined in the paper on “Numerical modeling of textured silicon solar cells using PC1D” by Basore (1990). The approximations underlying the analytical expression for L _eff are critically reviewed. Their impact on the determination of the minority carrier bulk diffusion length L_b from L_eff is discussed for a 250-μm thick Si solar cell. It is found that considerable errors occur in the case of diffusion lengths larger than the cell thickness even when neglecting any measurement uncertainty