Grain boundary modeling and characterization of thin-film silicon solar cells

An analytical model is developed to describe recombination currents arising from recombination at grain boundaries (GBs) in the depletion region of a p-n junction solar cell. Grain boundaries are modeled as having a single energy level in the energy gap, and partial occupancy of these states gives rise to a charge on the GB. The analytical model is compared to a complete numerical simulation package (DESSIS) and found to be in good agreement. Additionally, cross sectional EBIC images of a multilayer device containing vertical GBs are presented. Results derived from an analytical model are compared qualitatively to the experimental data and found to give good agreement.