Bulg. J. Phys. vol.36 no.2 (2009), pp. 131-138

Surface and Interface Polaritons of the Optical Phonons in Mg2Si Nanolayers with Rough Surfaces

G. Zlateva1, M. Baleva2
1University of Sofia, Faculty of Medicine, Koziak Str., 1407 Sofia, Bulgaria
2University of Sofia, Faculty of Physics, 5 J. Boucher Blvd., 1164 Sofia, Bulgaria
Abstract. Nanolayers of Mg2Si, embedded into $Si$ matrix by ion-beam synthesis are studied. The layers are prepared with the same dose of the implanted $Mg$ ions but with different energies of implantation and thus they are formed at different depth in the matrix. The surface of the samples is studied by atomic force microscopy (AFM) and the roughness height is determined. Raman scattering spectra of the samples are obtained and along with the characteristic Mg2Si phonon modes additional features are observed. These features are assigned to generation of surface and interface phonon-polariton modes. The samples are considered as a four-layered structure. The dispersion relations of the polariton modes are calculated from the boundary condition for a continuity of the polariton electric field. The features in the spectra are interpreted on the base of the calculated dispersion relations and the role of the surface roughness is evaluated.

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