Delta-doping for enhanced tunnel junction performance and thermal stability

In this work, we show that delta-doping can dramatically improve the performance of tunnel junctions. As an example, one of our delta-doped tunnel junctions achieved a peak current of 3.59 kA/cm
²
, while its structurally identical counterpart without delta-doping reached a peak current of just 7.32 mA/cm
²
. Several different tunnel junction designs were explored with differing amounts of optical absorption, and all showed significant improvement from delta-doping. With the benefit of delta doping, all tunnel junctions investigated here are able to survive top cell growth conditions and additional rapid thermal annealing.