A simplified Cu(In, Ga)(S, Se)2/Zn(O, S)/ZnO:Al stack for chalcopyrite thin-
film solar cells is proposed. In this stack the Zn(O, S) layer combines the
roles of the traditional CdS buffer and undoped ZnO layers. It will be shown
that Zn(O, S) films can be sputtered in argon atmosphere from a single mixed
target without substrate heating. The photovoltaic performance of the
simplified stack matches that of the conventional approach. Replacing the ZnO
target with a ZnO/ZnS target may therefore be sufficient to omit the CdS
buffer layer and avoid the associated complexity, safety and recycling issues,
and to lower production cost