Abstract
The surface structure of ultra-thin Al2O3 films on NiAl(110) and Ru(0001) was investigated by using high-resolution electron energy loss spectroscopy (HREELS). On a semi-empirical basis, the three phonon loss features, v(1) (380 similar to 430 cm(-1)), v(2) (620 similar to 660 cm(-1)), and v(3) (850 similar to 900 cm(-1)), of crystalline Al2O3 films were assigned to collective excitations of the microscopic vertical stretching motion of in-phase O-Al layers and to the stretching motions of the tetrahedrally and octahedrally coordinated Al-O species, respectively. To a good approximation, the distinct observation of the v(1) mode in the HREEL spectra of Al2O3 films can be a sign for the synthesis of a vertically well-defined Al2O3 phase. The relative intensity between the v(2) and the v(3) loss features has been used to determine the most probable oxide structure, amorphous, transition, or alpha-like, by using the relative site occupation ratio of Al3+ cations to hexagonal closely packed O2- anions. (C) 2000 Published by Elsevier Science B.V. All rights reserved.
Original language | English |
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Number of pages | 6 |
Journal | Surface Science |
Volume | 448 |
Publication status | Published - 10 Mar 2000 |
Keywords
- aluminum oxide
- crystallization
- electron energy loss spectroscopy (EELS)
- oxidation
- ruthenium
- surface structure, morphology, roughness and topography
- ENERGY-LOSS-SPECTROSCOPY
- ALUMINUM-OXIDE FILMS
- OXIDATION
- SYSTEM
- HREELS