RAMAN-SCATTERING OF INTERFACE MODES IN ZNTE-CDSE SUPERLATTICES

Raman spectra have been measured for ZnTe/CdSe superlattices grown by hot wall epitaxy, A mechanical vibrational interface phonon (MVIF) mod e localized at the Zn-Se interface is distinctly observed in addition to quasiconfined longitudinal optic (LO) modes, The relative intensity of the MVIF mode is increased as the period of the superlattice becom es short. Raman spectral profiles calculated by use of a linear chain model and a bond polarizability model explain this behavior qualitativ ely. The quasiconfined LO modes show resonant enhancement for excitati ons at the band gap energies of ZnTe and CdSe. The effect of atomic di ffusion on the interfacial structure has been examined in thermally an nealed superlattices by Raman measurement. It is shown that Raman scat tering of the interface mode provides information about the interdiffu sion of atoms and the sharpness of the heterointerfaces. (C) 1996 Amer ican Institute of Physics.