A Comparison of CdS and Zn(O,S) Buffer Layers in (Ag,Cu)(In,Ga)Se2 Solar Cells |
Michael F. Miller1, Ana Kanevce2, Marzieh Baan3, Rico Gutzler2, Darius Kuciauskas4, Theresa Magorian Friedlmeier2, Tyler J Grassman1,3, Aaron R Arehart1 1The Ohio State University, Department of Electrical and Computer Engineering, Columbus, OH, United States /2Zentrum fuer Sonnenenergie-und Wasserstoff-Forschung , Stuttgart, --, Germany /3The Ohio State University, Department of Materials Science and Engineering, Columbus, OH, United States /4National Renewable Energy Laboratory, Golden, CO, United States |
Cu(In,Ga)Se2-based solar cells typically use a CdS buffer layer, even though its relatively low bandgap causes parasitic absorption. While alternatives to CdS have been explored in other studies, limited results have been shown for Ag‑alloyed CIGS (ACIGS). In this study, ACIGS solar cells with both CdS and Zn(O,S) buffer layers were fabricated and compared for solar cell performance. The Zn(O,S) buffer slightly improved JSC through reduced absorption, although surface optimization is necessary. The Zn(O,S) ACIGS also had improved FF through reduced series resistance and ideality factor, which could be improved further through optimization. However, the VOC in the Zn(O,S) samples was reduced, likely due to increased bulk and front interface recombination. This study shows the promise of Zn(O,S) as a buffer layer in ACIGS solar cells and suggests pathways for further improvement. |