Lattice vibration in alternating monolayers of ZnSe and ZnTe is studie
d. Optical vibrational modes observed from (ZnSe)n-(ZnTe)n (n = 2, 3,
4) short-period superlattice are evaluated by a theoretical analysis u
sing the linear-chain model. A method of the calculation which can tak
e into account lattice strain is proposed. It is found that the zeroth
- and the first-order folded phonons in the ZnSe layer are observed in
Raman scattering. By investing the displacement of the atoms, it is a
lso found that the ZnSe-like LO mode is localized in the ZnSe layer, w
hereas no mode is localized in the ZnTe layer. This characterization i
s attributed to an overlap of the dispersion curves for ZnSe- and ZnTe
-LO modes in the strained layer.