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DS: Fachverband Dünne Schichten

DS 12: Postersession DS

DS 12.55: Poster

Montag, 7. März 2016, 17:00–19:00, Poster A

Ellipsometric characterization of doped SnO_x layers for novel SPR-based gas sensors — •Daniel Fischer¹, Andreas Hertwig¹, Uwe Beck¹, Martin Kormunda², and Norbert Esser³ — ¹BAM Federal Institute for Materials Research and Testing, Division 6.7 — ²J.E. Purkyne University, Faculty of Science, Department of Physics — ³Leibniz-Institut für Analytische Wissenschaften ISAS e.V.

In the present research a surface based gas detection technique is investigated using the SPR effect with ellipsometric readout. The sensor consists of a gold layer (∼40 nm) top-coated with a doped metal-oxide (M:SnO_x,∼5 nm). The coating was added by magnetron sputtering with doped targets and different doping concentration. In the past, it could be shown that these type of sensors can detect various gases, e.g. CO, H₂, O₂, O₃, He, N₂ with sensitivities down to the ppm range. The goal of the present study is to characterize the doped metal-oxide top-coating material in dependence of the coating conditions. Changing the properties of the plasma coating process and the doping gives access to a variety of different layer properties and enables us to find the best conditions for the determined gas in selectivity and sensitivity. The resulting layers are analyzed mainly by using spectroscopic ellipsometry to extract the optical constants n and k to find a correlation between the doping properties and the sensing ability for specific gas species. Further methods like TEM, XRD and TOF-SIMS are used to identify the structure of the surface and to extract the doping concentration of the coating.