Engineering Silicon Interfaces with Transparent Al_yTiO_x/ZnO/TiO_2 Stack Exhibiting Exceptional Passivating Contact Performance

摘要

Passivating contact technologies are essential for fabricating high-efficiencycrystalline silicon (c-Si) solar cells, and their application and incorporation intomanufacturing lines has ranked as a hot topic of research. Generally, idealpassivating contacts should combine excellent electrical contact, outstandingsurface passivation, and high optical transparency. However, addressing allthese criteria concurrently is challenging since it is unlikely for any singlematerial to exhibit both efficient carrier transport and surface-defect passivationwhile demonstrating negligible parasitic absorption. In this work, severalearth-abundant, wide-bandgap materials are combined to engineer highqualitytransparent electron-selective passivating contact structures capableof overcoming these obstacles. A highly transparent Al_yTiO_x/ZnO/TiO_2 stackwith a total thickness of 3 nm, prepared by atomic layer deposition, is shownto provide a close-to-ideal passivating contact to Si surfaces by enabling dualfunctions of remarkable silicon surface passivation (with an effective minoritycarrier lifetime of 12.3 ms, an implied open-circuit voltage of 730 mV, and asurface recombination current density prefactor of 2.6 fA cm~(?2)), combined withefficient carrier transport with a very low contact resistivity of 3.4 mΩ cm~2.These results demonstrate that low-cost silicon interface-engineering strategiesbasedon transition metal oxides can push c-Si solar cell performance toits theoretical limits.