P2.4.2 Molybdenum Oxide Nanorods Based Thin Films: Effect of Electrode Metallization on Hydrogen and Ethanol Sensing

14th International Meeting on Chemical Sensors - IMCS 2012
2012-05-20 - 2012-05-23
Nürnberg/Nuremberg, Germany
P2.4 Nanostructured Sensors
N. Illyaskutty, H. Kohler, T. Trautmann - Institute for Sensorics and Information Systems, Karlsruhe University of Applied Sciences (Germany), V. Pillai - Department of Optoelectronics, University of Kerala, Kariavattom (India), M. Schwotzer - Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT) (Germany)
1500 - 1503


Nanostructured molybdenum oxide (MoO3) gas sensitive layers were deposited on Au and Pt interdigitated electrodes (IDE) integrated to alumina substrates by RF magnetron sputtering and controlled post deposition annealing. Sensitivity test measurements towards hydrogen and ethanol vapour under non-humid and humid ambience at isothermal (200°C a nd 300°C) operation are presented. Extremely different response behaviour to the analytes depending on operating temperature, background humidity and electrode material was observed. The humid ambience does not significantly change the sensitivity to H2 whereas it diminishes the sensitivity to ethanol. Non-dissociative and dissociative adsorption of analytes on the sensing layer and diffusion effects due to different layer morphologies were taken into account in order to interpret the diverse sensing behaviour. Influence of the electrode material on the sensor performance of the MoO3 layers towards H2 and ethanol is demonstrated. The catalytic effect of the Pt-IDE on the sensitivity is identified at higher temperature (300°C).