Crystal-Field Effects at the TiO2−SiO2 Interface As Observed by X-ray Absorption Spectroscopy
| Autor: | José Sanz, and J. F. Trigo, Agustín R. González-Elipe, P. R. Bressler, Leonardo Soriano, C. Quirós, Gonzalo García Fuentes |
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| Rok vydání: | 2000 |
| Předmět: |
X-ray absorption spectroscopy
Materials science Absorption spectroscopy Analytical chemistry Surfaces and Interfaces Electronic structure Condensed Matter Physics Evaporation (deposition) Overlayer Amorphous solid Crystal Highly oriented pyrolytic graphite Electrochemistry General Materials Science Spectroscopy |
| Zdroj: | Langmuir. 16:7066-7069 |
| ISSN: | 1520-5827 0743-7463 |
| DOI: | 10.1021/la000330x |
| Popis: | The electronic structure of the TiO2−SiO2 interface has been investigated using X-ray absorption spectroscopy (XAS). TiO2 overlayers have been grown on two substrates, amorphous SiO2 and highly oriented pyrolytic graphite (for comparison), by evaporation of Ti in an oxygen atmosphere at room temperature. The evaporation rate was low enough to allow a detailed study of the early stages of growth, i.e., the submonolayer regime (θ < 1). The Ti 2p XAS spectra of the TiO2 overlayers have been measured for different coverages. The spectra corresponding to the submonolayer regime show an unusual shape not reported up to now. A comparison with existing atomic multiplet calculations indicates a significant decrease of the crystal field (≈0.7 eV) as compared with bulk TiO2 (≈1.7 eV) due to strong electronic interactions at the interface. The presence of the SiO2 substrate and the covalent character of the Si−O bonds lowers the crystal field of the TiO2 overlayer at the interface. In contrast, the graphite substrate... |
| Databáze: | OpenAIRE |
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