Filip Vysloužil

The response of tin acetylacetonate and tin dioxide-based gas sensors to hydrogen and alcohol vapours

The aim of this work is to investigate the properties of gas sensors with active layers prepared by pulsed laser deposition (PLD) technology. The active layers were deposited on planar sensor chips with interdigital platinum electrodes. The deposition was carried out from tin dioxide and tin acetylacetonate (SnAcAc) targets by KrF excimer laser. In some cases Pd catalyst was sputtered on the surface of the active layer. The ‘as-deposited’ sensors were submitted to heat treatment. The chemical composition of heat treated active layers was studied by XPS method. This method revealed the oxidation state of palladium and the distribution between organic and inorganic phase during the deposition of SnAcAc. The DC responses of the sensors to a reducing atmosphere containing 1000 ppm of hydrogen, methanol, ethanol, n-propanol and n-butanol were also measured. The maximum sensitivity S (ratio of sensor resistances SaRair/Rgas) achieved 67 for hydrogen, 21 for methanol, 50 for ethanol, 71 for n-propanol and 44 for n-butanol. The temperature of maximum sensitivity (Tmax )t o distinct gases, the influence of molecular weight of detected gas on Tmax and the influence of molecular weight on the sensor response speed are also discussed. # 2000 Elsevier Science B.V. All rights reserved.

Conductive Gas Sensors Prepared Using PLD

This contribution deals with conductive thin film gas sensors fabricated using laser technology. The principles of the pulsed laser deposition (PLD) technology is explained. Hybrid PLD systems, based on a combination of PLD and magnetron sputtering, PLD and RF discharges, and PLD with two laser targets are also presented. The growing layers can be modified by an ion beam. Organic films can be grown using the cryogenic MAPLE technology. Nanocrystalline and nanocomposite thin films for gas sensors can be deposited. Examples of layer fabrication and testing of layer properties for gas sensors are given.