Three-Dimensional TCAD Modeling of Grain Boundaries in High-Efficiency Silicon Solar Cells

Grain boundaries degrade the performance of solar cells based on polycrystalline materials; yet, device models rarely accurately account for all their effects or their spatially localized nature. Here, we use 3-D technology computer-aided design (TCAD) simulations to determine the effect of grain boundaries on the performance of silicon solar cells. We find that grain boundary-limited performance of multicrystalline silicon can approach that of monocrystalline silicon in high-efficiency devices. We identify higher carrier injection as a design feature that improves defect tolerance by reducing grain boundary charging, shrinking the depletion region surrounding the grain boundary.