Delta-Doping for Enhanced III-V Tunnel Junction Performance

Abstract

We show that delta-doping boosts the performance of tunnel junctions (TJs) used as interconnects in III-V multijunction solar cells by orders of magnitude. The peak current of our baseline TJ design consisting of p-GaAs/n-GaAs surrounded by $\text{Ga}_{0.51} \text{In}_{0.49}\text{P}$ clads is improved by a factor of similar to 5 x $10<^>5$. The relative benefits of delta-doping are even stronger in TJs based on wider-bandgap materials with reduced optical absorption. Importantly, we find that delta-doped TJs can survive the thermal loads that would be encountered during growth of additional subcells. Delta doping is a simple and versatile method to improve TJ performance that can be implemented by virtually any epitaxial growth method.