Passivating and low-resistive poly-Si tunneling junction enabling high-efficiency monolithic perovskite/silicon tandem solar cells

We present a p+/n+ poly-Si tunneling junction (TJ) based on a tunnel oxide passivated contact (TOPCon) that enables both low contact resistivity ρc and high implied open-circuit voltages iVoc. It will be shown that the charge carrier profile of the TJ and the junction resistance are strongly affected by the applied thermal budget, consisting of a furnace anneal and/or a rapid thermal processing treatment, and the deposition parameters of the a-Si layers. A minimum combined junction resistance of the p+/n+ poly-Si/SiOx stack of less than 10 mΩ cm2 and iVoc of up to 726 mV at 1 sun illumination is reported. This work aims for incorporation of our p+/n+ poly-Si TJ into an industrially feasible tandem solar cell featuring a Si bottom cell with a TOPCon front emitter and the industrial standard technology of a passivated emitter and rear cell rear structure.