Influence of substrate resistivity on the degradation of silicon solar cell performance due to crystal defects

The dependencies of minority carrier diffusion length and solar cell parameters on dislocation density were experimentally determined for silicon substrates of different resistivities. These data show that an increase in the substrate carrier concentration reduces the influence of dislocations on the carrier recombination and the cell parameters. Furthermore, the increase in V_oc and the decrease in J_sc that accompany a decrease in the substrate resistivity depend on the substrate dislocation density. This effect makes the optimum substrate resistivity a function of the average dislocation density of the substrate. These results dictate the choice of the substrate resistivity for obtaining optimum performance of solar cells fabricated on single-crystal or large-grain polycrystalline silicon of known average dislocation density.