Thin film sensors: The role of defects and impurity sites in controlling sensor response and selectivity
| Autor: | C. Arbour, C. Oden, J. P. Dodelet, Rossella. Brina, Neal R. Armstrong, J. W. Pankow, G. E. Collins |
|---|---|
| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films. 11:1383-1391 |
| ISSN: | 1520-8559 0734-2101 |
| DOI: | 10.1116/1.578558 |
| Popis: | Thin film gas sensors are discussed which are produced from polycrystalline organic dyes, such as the phthalocyanines, perylenes, etc. or from metal oxides, such as SnO2, ZnO, etc. Both types of materials are typically used to detect gas phase analytes by virtue of the surface conductance changes which accompany chemisorption of the analyte. In the case of the thin film oxides this process is understood in terms of the change in surface charge density and band bending which accompanies chemisorption of electron donors or acceptors. Defects in the oxide structure, or intentionally added impurities in the near surface region, can enhance the charge density at the surface and provide specific chemisorption sites for various analytes, which are the main means of introducing selectivity to these sensors. In the case of the organic dye thin films, hopping processes, rather than movement of charge through valence and conduction bands, control the flow of charge. Significantly higher defect and impurity densities... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|