The gas reponse of tin oxide sensors strongly depends on the preparation process and especially on depositioon parameters. For this reason, sensor elements have been prepared by depositing nanocrystalline tiun oxide at room temperature and at 250 deg C on polcrystalline alumina substrates by a reactive sputtering technique. It is seen that the response to gases is depednent on the tin oxide deposition temperature due to the structure change undergone by the oxide. The best resonse to low concentrations of carbon monoside and propanal is given by tin oxide sensors deposited at 250 deg C. Microstructural examination of these devices has been carried out using transmission electron mcroscopy. THe main difference observed in the tin oxide microstructure is the porosity. Sensors prepared at 250 deg C has a more compact microstructure.
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