Hall effect measurements are one of the most powerful techniques for obtaining information about the conduction mechanism in polycrystalline semiconductor materials, which is the basis for understanding semiconductor gas sensors. In order to investigate the correlation between the microscopic characteristics and the macroscopic performances exhibited by undoped tin oxide gas sensors deposited by spray pyrolysis, Hall effect measurements were performed at different temperatures, from room temperature up to 500 K, and in the presence of two different atmospheres, air and methane. From these measurements, it was possible to infer the potential barrier and its dependence with the used atmosphere. The obtained results were analysed in terms of the oxygen mechanism at grain boundaries on the basis of the grain boundary-trapping model. In the presence of methane gas, the electrical resistivity decreases due to the lowering of the inter-grain boundary barrier height.
|Title of host publication||Key Engineering Materials|
|Number of pages||4|
|Publication status||Published - 1 Jan 2002|
|Event||1st International Materials Symposium (Materials 2001) - Universidade de Coimbra, Coimbra, Portugal|
Duration: 9 Apr 2001 → 11 Apr 2001
|Conference||1st International Materials Symposium (Materials 2001)|
|Period||9/04/01 → 11/04/01|