1 Ev Gaassbn-Based Solar Cells For Efficient Multi-Junction Design: Enhanced Solar Cell Performance Upon Annealing

In this work, we demonstrate the beneficial effect of post-growth rapid thermal annealing (RTA) on the performance of -1 eV GaAsSbN-based solar cells. Different configurations of the dilute nitride material are studied: a bulk quaternary GaAsSbN layer and type-II GaAsSb/GaAsN superlattices (SL) with different period thickness. The RTA treatment leads in both types of structures to an enhanced external quantum efficiency (EQE) and reduced values of the dark saturation current and series resistance. The origin of these improvements is attributed to reduced densities of N and Sb-rich clusters and point defects. Remarkably, all solar cell parameters are substantially improved, this being particularly significant for the short circuit current density (JSC) and power conversion efficiency (PCE), the latter with a relative enhancement as high as 500%. The large increment of JSC is an important step towards current-matching in multi-junction solar cells containing GaAsSbN structures.