Dr Christian A. KAUFMANN

Dr Christian A. KAUFMANN

Group Leader
PVcomB / Helmholtz-Zentrum Berlin für Materialien und Energie, Germany

Fast Atmospheric Chalcogenization of Metallic Cu-In-Ga Precursors

Sequential processing of Cu(In,Ga)(S,Se)2 (CIGS) absorber layers is a viable industrial process for CIGS solar module fabrication. Large-scale state of the art technology still relies on the use of toxic gases such as H2Se/H2S for chalcogenization, driving up production costs. Here we present a sequential process routine, which employs fast atmospheric in-line chalcogenization of sputtered Cu-In-Ga precursors on Mo-coated glass using elemental Se and S as chalcogen sources. Ga aggregation at the back contact - as generally seen in sequentially processed CIGS thin films – and sulfurization of a partially selenized precursor seems to give good control over the in-depth Eg grading of the complete absorber. We find that type and amount of Na supply have considerable impact on the S in-depth profile. In addition sulfur implementation can result in evolution of different device defects such as e.g. the development of a barrier at the front (CIGSSe/CdS) or back interface


Dr. Christian A. Kaufmann has completed his first degree in physics at the Free University of Berlin, Germany, and spent the years working on his PhD in Engineering Science at the University of Oxford, Great Britain, working on a Cd-free buffer layer technology for CuInS2 thin film solar cell devices. Back in Berlin he joined the HZB to work on the transfer of the CIGSe solar cell thin film technology to flexible substrates such as titanium, steel or polyimide foil. One main focus of this work has been to develop a flexible CIGSe technology for space applications. Since 2014 he is group leader for the CIGSSe development at the PVcomB (co-evaporation and sequential growth) with a focus on technology transfer for industrially relevant processes for CIGSSe absorber fabrication.