Properties of Co-Evaporated RbInSe2 Thin Films

The formation of an Rb-containing In-Se compound at the surface of Cu(In,Ga)Se-2 (CIGS) thin films is assumed to be part of the mechanism of RbF post-deposition treatments (PDTs) performed on these absorber layers. Alkali-PDTs have acquired attention lately as they significantly enhance the efficiency of CIGS solar cells. In this contribution the formation of various phases during the RbF-PDT has been investigated. The results indicate that RbInSe2 is the most probable phase to form. Combining theoretical and experimental investigations, fundamental properties of a thermally co-evaporated RbInSe2 thin film are reported in order to serve as reference values in further studies.