Abstract
The mode behaviors of the zone-edge phonons in the pseudo-binary layer-type semiconductor GaSxSe1−x (0≤x≤1) have been analyzed in terms of the inelastic electron tunneling (IET) spectra in Pb-GaSxSe1−x-Pb junctions. The IET spectral peaks correspond to those phonon energies with their extrema in the density of states at the zone-edges. The x-dependence of the phonon energy thus determined indicates that most of these phonons exhibit two-mode behaviors.