Two types of MOx sensor structures, SnO₂ and WO₃, of different thicknesses were synthesized on top of the interdigitated Au electrodes and used for the measurements of the ethylene gas. The SEM micrographs revealed inhomogeneities of the WO₃ layer and the presence of cracks on the edges of Au electrodes which correlates with the lack of reproducibility of the WO₃ sensors. Both sensor structures showed a significant sensitivity to ethylene gas: the sensitivities of both MOx-types were higher at higher temperatures which was more evident in the case of SnO₂ structure. The SnO₂ layer had approximately 5-times higher sensitivity than the WO₃ sensor of the same thickness. The saturation (T10) and desaturation (T90) times were shorter for WO₃ sensors at lower temperatures while SnO₂ was saturated and desaturated faster at higher temperatures. Sensors with thinner active layer possessed higher sensitivities and shorter T10 and T90 times.

Date Published: 21 May 2015
PDF: 8 pages
Proc. SPIE 9517, Smart Sensors, Actuators, and MEMS VII; and Cyber Physical Systems, 951713 (21 May 2015); doi: 10.1117/12.2179235

Published in SPIE Proceedings Vol. 9517:
Smart Sensors, Actuators, and MEMS VII; and Cyber Physical Systems
José Luis Sánchez-Rojas; Riccardo Brama, Editor(s)