Lattice Phonon Spectra of Aluminum Oxide Anodic Films

Techniques have been developed for obtaining reproducible lattice phonon spectra of barrier aluminum oxide anodic films. Changes in the lattice phonon spectrum as a result of 15-keV proton bombardment are interpreted in terms of the formation of Al-OH bonds. Polarization spectra of stripped and unstripped aluminum oxide films confirm the findings of Vedder and Vermilyea, particularly with respect to the origin of the 960 cm −1 band. The close similarity in the observed and calculated band shapes (using the theory of Berreman) leave little doubt that the 960 cm −1 absorption is due to a longitudinal optic mode of the aluminum oxide lattice.