Separation of bulk diffusion length and rear surface recombination velocity in SR-LBIC mappings

SR-LBIC measurements are an important tool for mapping effective diffusion lengths of processed solar cells. This paper investigates the extraction of bulk diffusion length and back surface recombination velocities from SR-LBIC data. Two models for fitting data are studied, one of which takes account for a physical model proposed by Basore (1993), the other one, Spiegel et al. (2000), is a simplification thereof. Simulations with varying noise levels show, that noise is a more severe problem for L_bulk and S_back mappings as compared to L_eff mappings, though it should be possible to generate L_bulk and S_back mappings, if the noise level is below approximately 3%. First results of SR-LBIC data analysed with this tool are presented showing the necessity of having at least one measurement at a wavelength that corresponds to a penetration depth around half of the cell thickness.