Junction formation by Zn(O,S) sputtering yields CIGSe-based cells with efficiencies exceeding 18

ABSTRACT 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. Copyright © 2013 John Wiley & Sons, Ltd. A CIGSe/Zn(O,S)/ZnO:Al solar cell with a confirmed efficiency of 18.3% demonstrates the feasibility of junction formation by sputtering. This result was achieved without any surface treatments, annealing, or light soaking. This opens up a very attractive route to Cd‐free chalcopyrite‐based modules without a dedicated buffer layer.