On the effect of KInSe2 (KIS) layer on Cu(In,Ga)Se2 solar cell performance: a numerical study

In this work we use numerical simulations to investigate the potential impact of the presence of a KInSe
₂
(KIS) layer on the CIGS surface due to KF post-deposition treatment (PDT). Although we focus on a KIS layer, due to the generality of the approach our results can be extended to other Alk-InSe
₂
of similar energy gap (larger than the CIGS bandgap), since no hypotheses have been made on the layer composition except for the energy gap being large enough to make it transparent to the AM1.5G spectrum. We consider different values for the KIS electron affinity, resulting in a range of conduction band offsets with CIGS and CdS, in the case of trap-free KIS or KIS with acceptor traps. We also evaluate the effect of the KIS layer on the cell current-voltage characteristics at low temperature.