Tuning the (Zn,Mg)O Layer Thickness for Improved Efficiency in CIGS Solar Cells with Zn(O,S) Buffer: A Numerical Investigation |
Giovanna Sozzi1, Lorenzo Perini1, Wolfram Witte2, Dimitrios Hariskos2 1Department of Engineering and Architecture, University of Parma, Parma, --, Italy /2Zentrum für Sonnenenergie -und Wasserstoff-Forschung Baden-Württemberg (ZSW), Stuttgard, --, Germany |
We investigate the behavior of the solar cell with layer sequence ZnO:Al/Zn0.75Mg0.25O/Zn(O,S)/CIGS for various Zn0.75Mg0.25O (ZMO) thicknesses by comparing the measured cell parameters with the ones obtained by numerical simulations. The combined effects of different conduction band alignments at heterointerfaces, carrier lifetime in the CIGS bulk, and ZMO layer thickness are analyzed. The impact on the cell performance of acceptor defects at the CIGS/Zn(O,S) interface is also studied. The optimal ZMO thickness corresponding to the highest conversion efficiency is then calculated for all the different conditions. |