Surface structure of ultra-thin Al2O3 films on metal substrates

M B Lee, J H Lee, B G Frederick, N V Richardson

Research output: Contribution to journalLetterpeer-review

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 languageEnglish
Number of pages6
JournalSurface Science
Volume448
Publication statusPublished - 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

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