Recent measurements performed on epitaxial layers clearly demonstrate the capability of HREELS to observe interface optical phonons in dielectric layered materials. Two examples are presented: First, the case of epitaxial CaF on Si(111) where the CaF interface phonon is detected for a whole range of CaF layer thicknesses. Discrepancies with theoretical predictions are interpreted as resulting from the residual strain in the CaF layers. The second example is a III-V semiconductor superlattice GaAs-AlGaAs in which an Al-As type interface mode is clearly identified and quantitatively interpreted by the dielectric theory.
|Number of pages||6|
|Publication status||Published - 2 Oct 1987|