Monolithic Cu2ZnSnS4-on-Silicon Tandem Solar Cells Enabled by a Diffusion Barrier (original) (raw)

Recently, Si-based tandem solar cells have been the most compelling strategy to improve the efficiency of the existing photovoltaic technology beyond its practical and theoretical limits. Thin-film chalcogenides have shown performance, reliability, stability and costs comparable to the Si technology, and could be suitable top-cell partners for Si. However, limited work has been done to evaluate the compatibility of these two technologies. The synthesis process of chalcogenides generally includes high temperature annealing (> 500 oC) of the precursors in a reactive atmosphere, which could lead to in-diffusion of the detrimental metallic species into the Si cell. In this work, we investigated monolithic integration of Cu2ZnSnS4 (CZTS), a promising representative from the chalcogenides family, on top of a thermally resilient silicon structure featuring polysilicon-based electron and hole selective passivating contacts. We used different Ti-based barrier layers, namely TiN, Ti(OxNy),...