Extracting Surface Saturation Current Density from Lifetime Measurements of Samples with Metallized Surfaces

The surface recombination at metallized surfaces of a solar cell is of significant interest to process developers, considering the limiting effect such recombination has on cell efficiency. This recombination is difficult to measure accurately because the higher recombination at metallized surfaces compared to other passivated surfaces causes an inhomogeneous minority carrier profile. In this study, a novel photoluminescence-based system is used to measure the injection dependent effective lifetime of metallized samples, and several techniques to extract surface recombination parameters are compared. A simulation-based approach is shown to be superior to the simplified analyses that are more commonly applied to data of this type, in the case where the minority carrier profile is non-uniform.