Regensburg 2019 – wissenschaftliches Programm
HL 45.16: Poster
Donnerstag, 4. April 2019, 18:30–21:00, Poster E
Electroreflectance studies of CdS buffers in CIGS solar cells: Influence of Ga content and thermal annealing on the CdS bandgap — •Nico Weber1, Jasmin Seeger1, Jonas Grutke1, Wolfram Witte2, Dimitrios Hariskos2, Oliver Kiowski2, Heinz Kalt1, and Michael Hetterich1,3 — 1Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany — 2Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), 70563 Stuttgart, Germany — 3Light Technology Institute, KIT, 76131 Karlsruhe, Germany
Cu(In,Ga)Se2 (CIGS) has proven to be ideally suited as absorber material for high efficiency thin-film solar cells due to its excellent optical and electrical properties. In order to further improve the CIGS solar cells, a detailed understanding of the absorber–buffer interface is required. For this purpose, CIGS solar cells with the commonly used CdS buffer layer are investigated utilizing angle-resolved electroreflectance (ARER) spectroscopy. This new approach enables an accurate and destruction-free bandgap energy determination of the buffer layer despite the occurring interference effects caused by the layer stack. Therefore, ARER can provide information about possible interdiffusion processes between buffer and absorber layers. In this contribution, we employ ARER to study the impact of different gallium contents of the absorber on the bandgap energy of the buffer layer. In addition, the influence of thermal annealing on the bandgap energy of the buffer layer is investigated.