E8.2 - Nanostructured WO3 Semiconductor Gas Sensor for Selective Detection of Naphthalene
- AMA Conferences 2015
2015-05-19 - 2015-05-21
- Proceedings SENSOR 2015
- E8 - Gas Sensors IV
- M. Leidinger, T. Sauerwald, A. Schütze - Saarland University, Saarbrücken (Germany), J. Huotari, J. Lappalainen - University of Oulu, Oulu (Finland)
- 723 - 728
Pulsed laser deposition at room temperature was used to prepare WO3 layers on MEMS micro heater platforms obtaining porous layers of nanoparticles and nanoparticle agglomerates. The layer structure and the related gas sensing properties were shown to be highly dependent on the deposition parameters, especially the oxygen pressure. At an oxygen pressure of 0.2 mbar the formation of Ɛ- phase WO3 was found resulting in an increased sensitivity of the sensor material. The gas sensing performance was determined by exposing the WO3 sensor devices to volatile organic compounds (benzene, formaldehyde, naphthalene) at ppb level concentrations and ethanol background at ppm level concentrations. The sensors were operated in temperature cycled operation; the signal processing was performed using linear discriminant analysis based on shape features extracted from the conductance signals. Both tested sensor layers showed high sensitivity and selectivity to naphthalene compared to the other test gases. The sensor layer deposited at higher oxygen partial pressure performed better for discriminating the gases and naphthalene concentrations. With this sensor, 1 ppb of naphthalene could be detected in a 1 ppm ethanol background with very high reliability. Furthermore a discrimination of 5 ppb of naphthalene from lower concentrations for quantification purposes was possible.