Formation of transparent and ohmic ZnO:Al/MoSe2 contacts for bifacial Cu(In,Ga)Se2 solar cells and tandem structures

Cu(In,Ga)Se-2 layers are fabricated by thermal coevaporation on transparent ZnO:Al films. A thin opaque Mo interlayer inserted between the ZnO:Al and the Cu(In,Ga)Se-2 film transforms the rectifying ZnO:Al/CIGS interface into an ohmic contact. Transparency of the ZnO:Al/Mo backcontact is achieved by depositing an additional NaF precursor, which catalyses the redox selenisation of the opaque Mo to transparent MoSe2 during the Cu(In,Ga)Se-2 evaporation process. Cu(In,Ga)Se-2 solar cells with efficiencies up to 13.4% are fabricated on transparent ZnO:Al/MoSe2 backcontacts. (c) 2004 Published by Elsevier B.V.