Gettering in PolySi/SiO Passivating Contacts Enables Si-Based Tandem Solar Cells with High Thermal and Contamination Resilience.

Multijunction solar cells in a tandem configuration could further lower the costs of electricity if crystalline Si (c-Si) is used as the bottom cell. However, for direct monolithic integration on c-Si, only a restricted number of top and bottom cell architectures are compatible, due to either epitaxy or high-temperature constraints, where the interface between subcells is subject to a trade-off between transmittance, electrical interconnection, and bottom cell degradation. Using polySi/SiO passivating contacts for Si, this degradation can be largely circumvented by tuning the polySi/SiO stacks to promote gettering of contaminants admitted into the Si bottom cell during the top cell synthesis.