Enhancement of radiation tolerance with the use of a doping superlattice solar cell

摘要

Solar cells utilizing doping superlattices in the active region of the device have been proposed as an alternative design to increase radiation hardness. Multiple diodes are connected together in parallel, where each diode can be as thin or thick as the design requires. Thinning the doped layers reduces the diffusion length requirements ensuring efficient carrier collection and maintenance of short circuit current. Experimental comparisons between nipi and a conventional pin solar cells that were irradiated with 1 MeV electrons at fluences from 4×10~(14) to 2×10~(15) e~-/cm~2 show much more efficient maintenance of efficiency for the nipi design, maintaining nearly 100% efficiency up to a final dose of 2×10~(15) e~-/cm~2. Further simulations have indicated that the efficient maintenance of voltage and fill factor are likely due to traps created in the nipi solar cell during the fabrication process. Beginning of life voltage and efficiency values can be improved significantly by limiting the trap density, while this has a minor impact on the efficiency comparison between a nipi and conventional device with respect to radiation.