Sputtered Zn(O,S): a promising approach to dry inline fabrication of Cdfree CIGS modules

Sputtering of Zn(O,S) has emerged as an alternative technology for establishing the pn-junction for Cd-free chalcopyrite-based solar cells. Compared to the chemical bath deposition of CdS, this technology promises dry in-line fabrication of Cd-free modules with reduced complexity and cost. We will review the milestones of its development from fundamental investigations to scaling-up on large area sputter coaters. Reactive sputtering from ZnS targets has been used to initially assess basic film properties over the whole range of compositions from ZnO to ZnS. Subsequently, the process has been simplified and brought closer to industrial application by switching to mixed ZnO/ZnS targets.