Adjusting the Ga grading during fast atmospheric processing of Cu(In,Ga)Se2solar cell absorber layers using elemental selenium vapor

We study the Cu(In,Ga)Se2 absorber fabrication by fast atmospheric pressure selenization of metal precursor films utilizing elemental selenium vapor from independent sources. We find that a high Se supply during selenization leads to the generally observed Ga accumulation at the back contact, while a reduced Se supply leads to a more homogeneous Ga distribution within the absorber. By optimizing the precursor as well as the Ga in‐depth distribution in the CIGSe layer, a conversion efficiency of 15.5% was achieved.