In an effort to reduce the complexity and associated production costs of
Cu(In,Ga)Se2 (CIGSe)-based solar cells, the commonly used sputtered undoped
ZnO layer has been modified to eliminate the requirement for a dedicated
buffer layer. After replacing the ZnO target with a mixed ZnO/ZnS target,
efficient solar cells could be prepared by sputtering directly onto the as-
grown CIGSe surface. This approach has now been tested with high-quality lab-
scale glass/Mo/CIGSe substrates. An efficiency of 18.3% has been independently
confirmed without any post-deposition annealing or light soaking.