Regensburg 2016 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 90: Poster III

HL 90.3: Poster

Thursday, March 10, 2016, 16:00–19:00, Poster A

Kelvin Probe Force Microscopy Studies of CIGS Solar Cells — •Jasmin Seeger¹, Zhenhao Zhang^2,4, Wolfram Witte³, Michael Powalla^2,3, Heinz Kalt¹, and Michael Hetterich¹ — ¹Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany — ²Light Technology Institute, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany — ³Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), 70565 Stuttgart, Germany — ⁴Present address: Singulus Technologies AG, 63796 Kahl am Main, Germany

Cu(In,Ga)Se₂ (CIGS) is a well-established absorber material for thin-film solar cells, achieving conversion efficiencies of up to 21.7%. In order to further improve this performance, a detailed understanding of the potential distribution (width of the space charge region etc.) in these devices is essential. Of particular interest are the impact of alternative buffer materials or a variation of the gallium content of the absorber on the device performance. To study this impact we investigate the surface as well as the cleaved edge of CIGS solar cells utilizing Kelvin Probe Force Microscopy (KPFM). The contact potential difference (CPD) is studied through the complete structure, partly even on illuminated operating devices. The results are correlated with complementary data such as I-V characteristics and give insights into loss mechanisms in CIGS solar cells.