TY - JOUR A1 - Beck, Uwe A1 - Hertwig, Andreas A1 - Kormunda, M. A1 - Krause, Andreas A1 - Krüger, Hannes A1 - Lohse, Volkmar A1 - Nooke, Alida A1 - Pavlik, J. A1 - Steinbach, J. T1 - SPR enhanced ellipsometric gas monitoring on thin iron doped tin oxide layers JF - Sensors and actuators B: Chemical N2 - In this work, thin iron doped tin oxide layers (3–6 nm) were investigated with regard to gas sensitivity by means of surface plasmon resonance (SPR) effect with ellipsometric readout. The experimental set-up was a Kretschmann configuration with gold as metal layer. The sensor system was exposed to different concentrations of methane in the low ppm range and the sensor response of an uncoated gold layer compared to a gold layer coated with iron doped tin oxide. The additional layer effects stability with regard to drift behavior of the sensor and an increase in sensitivity. Furthermore, the sensor is able to detect the toxic gas carbon monoxide in low concentration range (down to 0.5 ppm). The thin layers were investigated by X-ray photoelectron spectroscopy, secondary electron microscopy and spectroscopic ellipsometry. The possible mechanisms taking place on the surface are discussed. KW - Gas sensing KW - SPR effect KW - Iron doped tin oxide KW - Ellipsometry PY - 2011 DO - https://doi.org/10.1016/j.snb.2011.08.036 SN - 0925-4005 SN - 1873-3077 VL - 160 IS - 1 SP - 609 EP - 615 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-24826 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nooke, Alida A1 - Beck, Uwe A1 - Hertwig, Andreas A1 - Krause, Andreas A1 - Krüger, Hannes A1 - Lohse, Volkmar A1 - Negendank, Detlef A1 - Steinbach, J. T1 - On the application of gold based SPR sensors for the detection of hazardous gases JF - Sensors and actuators B: Chemical N2 - A gas sensor system based on the surface plasmon resonance (SPR) effect in a 44 nm Au layer was studied. The usability of this sensor system was investigated for several analyte gases and gas mixtures which are interesting due to their flammability, toxicity or greenhouse effect. The SPR effect of gold was measured in nitrogen and compared with the gaseous alkane series which caused a shift of the position of the SPR effect. For in situ measurements, the phase shift Δ at the SPR angle (ψ minimum) in the analyte gas mixtures was measured for investigated gases in comparison with nitrogen. With this method, detection limits of different gases could be determined, which lie in a range interesting for safety engineering. Furthermore the aging effect of the gold layers which leads to loss in sensitivity of the sensor was investigated. KW - Ellipsometry KW - SPR effect KW - Gas sensing KW - Gold layer PY - 2010 DO - https://doi.org/10.1016/j.snb.2010.05.061 SN - 0925-4005 SN - 1873-3077 VL - 149 IS - 1 SP - 194 EP - 198 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-21673 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nooke, Alida A1 - Beck, Uwe A1 - Hertwig, Andreas A1 - Krause, Andreas A1 - Krüger, Hannes A1 - Lohse, Volkmar A1 - Negendank, Detlef A1 - Steinbach, J. T1 - Ellipsometric detection of gases with the surface plasmon resonance effect on gold top-coated with sensitive layers JF - Thin solid films N2 - An ellipsometric gas sensor based on the surface Plasmon resonance (SPR) effect of ~ 43 nm thick gold layers was investigated. To protect the gold layer from contamination and to improve the detection limits, the gold layers were top-coated with 5–6 nm thick layers of organic a-C:H or with inorganic metal oxides TiO2 or ZrO2. The additional layers increased the long-term stability, whereas the metal oxide layers protect better than a-C:H. Furthermore, the additional layers decreased the detection limits by one order of magnitude in case of a-C:H and two orders of magnitude in case of the oxides. It could be shown that the detection limits also depend on the kind of preparation (sol–gel process or physical vapour deposition) of the additional layers. KW - Gas sensor KW - SPR KW - Ellipsometry KW - Sensitive layer KW - TiO2 KW - ZrO2 KW - a-C:H PY - 2011 DO - https://doi.org/10.1016/j.tsf.2010.11.091 SN - 0040-6090 VL - 519 IS - 9 SP - 2659 EP - 2663 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-23353 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -