Fabrication of Cu(In,Ga)Se2 solar cells by a novel single-stage route based on Pulsed Electron Deposition (PED)

A novel route for fabricating Cu(In,Ga)Se2 (CIGS) thin films solar cells, based upon the Pulsed Electron Deposition (PED) technique is presented. Unlike other well-known deposition techniques, PED process allows the stoichiometric deposition of CIGS layers in a single stage, without requiring any further treatments for Cu/(In+Ga) ratio adjustment. Moreover controlling of Na doping in CIGS films can be easily achieved by introducing Na2Se in the target. PED technique can also be utilized to deposit the remaining layers of solar cell: the subsequent deposition of buffer and TCO layers can be easily realized by using a multi-target carousel, without removing the sample from the PED vacuum system. In this way a faster, safer and cheaper fabrication process can be attained. The preliminary results on performances of solar devices based on these films (? > 8%) confirm the great potentiality of PED technique in CIGS-based solar cell fabrication.