Zn(O, S) layers for chalcoyprite solar cells sputtered from a single targetA. Grimm, D. Kieven, I. Lauermann, M.Ch. Lux-Steiner, F. Hergert, R. Schwieger and R. KlenkEPJ Photovolt., 3 (2012) 30302DOI: https://doi.org/10.1051/epjpv/2012011