Influence of Na on the properties of Cu-rich prepared CuInS2 thin films and the performance of corresponding CuInS2/CdS/ZnO solar cells

Using different glass substrate types the Na content in sequentially and Cu -rich prepared CuInS2 films and corresponding CuInS2/CdS/ZnO thin-film sola r cells is varied. The purpose was to investigate the influence of differen t Na concentrations on absorbers and devices. While the morphology of the a bsorbers seems not to be affected by this variation, corresponding PL spect ra differ significantly. The properties of the solar cells, however, show n o dependence on the Na concentration. This implies that even though the def ect chemistry of CuInS2, sequentially prepared under Cu excess, is changed by the presence of Na this influence has no impact on properties of corresp onding solar cells. (C) 2001 Elsevier Science B.V. All rights reserved.