Dresden 2017 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 90: Inhomogeneous Materials for Solar Cells

HL 90.3: Talk

Friday, March 24, 2017, 12:00–12:15, POT 81

Band gap changes in Cu₂ZnSn(S,Se)₄ solar cell absorbers with varying Cu concentration — •Mario Lang¹, Tobias Renz¹, Niklas Mathes¹, Markus Neuwirth¹, Thomas Schnabel², Simon Woska¹, Heinz Kalt¹, and Michael Hetterich^1,3 — ¹Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany — ²Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg, 70565 Stuttgart, Germany — ³Light Technology Institute, KIT, 76131 Karlsruhe, Germany

The efficiency of Cu₂ZnSn(S,Se)₄ solar cells highly depends on the composition of the absorber layer. A Cu-poor and Zn-rich composition is crucial for highly efficient devices. This is due to the fact that unwanted and harmful secondary phases and defects are reduced in this case. The effect of the Cu content is not only relevant for the efficiency but also for certain optical device parameters as, e.g., the band gap. In this contribution we analyse the influence of the Cu content of Cu-poor Cu₂ZnSn(S,Se)₄ solar cell absorbers on several optical properties and device parameters. We find an increase in band gap with decreasing Cu content whereas the band tailing does not change. Furthermore, the defect luminescence shifts in parallel to the band gap but does also not change its nature.