Design, preparation and performance of Cu(In, Ga)(S, Se)2/Zn(O, S)/ZnO:Al solar cells

Junction formation by chemical bath deposition of CdS is a well established and robust process. To avoid the well known drawbacks of this approach, we propose to omit the CdS buffer layer and to directly sputter a modified window layer where Zn(O, S) is used instead of ZnO to improve the band line-up. This could result in completely dry in-line manufacturing of Cd-free modules using only proven deposition technologies. Key requisites for a new module structure are that the efficiency is not adversely affected and that the process is stable with a wide process window. For a first assessment, tests were carried out using absorbers from industrial production.